Updating trunk VERSION from 2139.0 to 2140.0

[chromium-blink-merge.git] / pdf / pdfium / pdfium_engine.cc

// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "pdf/pdfium/pdfium_engine.h"

#include <math.h>

#include "base/json/json_writer.h"
#include "base/logging.h"
#include "base/memory/scoped_ptr.h"
#include "base/stl_util.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/string_piece.h"
#include "base/strings/string_util.h"
#include "base/strings/utf_string_conversions.h"
#include "base/values.h"
#include "pdf/draw_utils.h"
#include "pdf/pdfium/pdfium_mem_buffer_file_read.h"
#include "pdf/pdfium/pdfium_mem_buffer_file_write.h"
#include "ppapi/c/pp_errors.h"
#include "ppapi/c/pp_input_event.h"
#include "ppapi/c/ppb_core.h"
#include "ppapi/c/private/ppb_pdf.h"
#include "ppapi/cpp/dev/memory_dev.h"
#include "ppapi/cpp/input_event.h"
#include "ppapi/cpp/instance.h"
#include "ppapi/cpp/module.h"
#include "ppapi/cpp/private/pdf.h"
#include "ppapi/cpp/trusted/browser_font_trusted.h"
#include "ppapi/cpp/url_response_info.h"
#include "ppapi/cpp/var.h"
#include "third_party/pdfium/fpdfsdk/include/fpdf_ext.h"
#include "third_party/pdfium/fpdfsdk/include/fpdf_flatten.h"
#include "third_party/pdfium/fpdfsdk/include/fpdf_searchex.h"
#include "third_party/pdfium/fpdfsdk/include/fpdf_sysfontinfo.h"
#include "third_party/pdfium/fpdfsdk/include/fpdf_transformpage.h"
#include "third_party/pdfium/fpdfsdk/include/fpdfedit.h"
#include "third_party/pdfium/fpdfsdk/include/fpdfoom.h"
#include "third_party/pdfium/fpdfsdk/include/fpdfppo.h"
#include "third_party/pdfium/fpdfsdk/include/fpdfsave.h"
#include "third_party/pdfium/fpdfsdk/include/pdfwindow/PDFWindow.h"
#include "third_party/pdfium/fpdfsdk/include/pdfwindow/PWL_FontMap.h"
#include "ui/events/keycodes/keyboard_codes.h"

namespace chrome_pdf {

#define kPageShadowTop    3
#define kPageShadowBottom 7
#define kPageShadowLeft   5
#define kPageShadowRight  5

#define kPageSeparatorThickness 4
#define kHighlightColorR 153
#define kHighlightColorG 193
#define kHighlightColorB 218

const uint32 kPendingPageColor = 0xFFEEEEEE;

#define kFormHighlightColor 0xFFE4DD
#define kFormHighlightAlpha 100

#define kMaxPasswordTries 3

// See Table 3.20 in
// http://www.adobe.com/devnet/acrobat/pdfs/pdf_reference_1-7.pdf
#define kPDFPermissionPrintLowQualityMask  1 << 2
#define kPDFPermissionPrintHighQualityMask 1 << 11
#define kPDFPermissionCopyMask             1 << 4
#define kPDFPermissionCopyAccessibleMask   1 << 9

#define kLoadingTextVerticalOffset 50

// The maximum amount of time we'll spend doing a paint before we give back
// control of the thread.
#define kMaxProgressivePaintTimeMs 50

// The maximum amount of time we'll spend doing the first paint. This is less
// than the above to keep things smooth if the user is scrolling quickly. We
// try painting a little because with accelerated compositing, we get flushes
// only every 16 ms. If we were to wait until the next flush to paint the rest
// of the pdf, we would never get to draw the pdf and would only draw the
// scrollbars. This value is picked to give enough time for gpu related code to
// do its thing and still fit within the timelimit for 60Hz. For the
// non-composited case, this doesn't make things worse since we're still
// painting the scrollbars > 60 Hz.
#define kMaxInitialProgressivePaintTimeMs 10

// Copied from printing/units.cc because we don't want to depend on printing
// since it brings in libpng which causes duplicate symbols with PDFium.
const int kPointsPerInch = 72;
const int kPixelsPerInch = 96;

struct ClipBox {
  float left;
  float right;
  float top;
  float bottom;
};

int ConvertUnit(int value, int old_unit, int new_unit) {
  // With integer arithmetic, to divide a value with correct rounding, you need
  // to add half of the divisor value to the dividend value. You need to do the
  // reverse with negative number.
  if (value >= 0) {
    return ((value * new_unit) + (old_unit / 2)) / old_unit;
  } else {
    return ((value * new_unit) - (old_unit / 2)) / old_unit;
  }
}

std::vector<uint32_t> GetPageNumbersFromPrintPageNumberRange(
    const PP_PrintPageNumberRange_Dev* page_ranges,
    uint32_t page_range_count) {
  std::vector<uint32_t> page_numbers;
  for (uint32_t index = 0; index < page_range_count; ++index) {
    for (uint32_t page_number = page_ranges[index].first_page_number;
         page_number <= page_ranges[index].last_page_number; ++page_number) {
      page_numbers.push_back(page_number);
    }
  }
  return page_numbers;
}

#if defined(OS_LINUX)

PP_Instance g_last_instance_id;

struct PDFFontSubstitution {
  const char* pdf_name;
  const char* face;
  bool bold;
  bool italic;
};

PP_BrowserFont_Trusted_Weight WeightToBrowserFontTrustedWeight(int weight) {
  COMPILE_ASSERT(PP_BROWSERFONT_TRUSTED_WEIGHT_100 == 0,
                 PP_BrowserFont_Trusted_Weight_Min);
  COMPILE_ASSERT(PP_BROWSERFONT_TRUSTED_WEIGHT_900 == 8,
                 PP_BrowserFont_Trusted_Weight_Max);
  const int kMinimumWeight = 100;
  const int kMaximumWeight = 900;
  int normalized_weight =
      std::min(std::max(weight, kMinimumWeight), kMaximumWeight);
  normalized_weight = (normalized_weight / 100) - 1;
  return static_cast<PP_BrowserFont_Trusted_Weight>(normalized_weight);
}

// This list is for CPWL_FontMap::GetDefaultFontByCharset().
// We pretend to have these font natively and let the browser (or underlying
// fontconfig) to pick the proper font on the system.
void EnumFonts(struct _FPDF_SYSFONTINFO* sysfontinfo, void* mapper) {
  FPDF_AddInstalledFont(mapper, "Arial", FXFONT_DEFAULT_CHARSET);

  int i = 0;
  while (CPWL_FontMap::defaultTTFMap[i].charset != -1) {
    FPDF_AddInstalledFont(mapper,
                          CPWL_FontMap::defaultTTFMap[i].fontname,
                          CPWL_FontMap::defaultTTFMap[i].charset);
    ++i;
  }
}

const PDFFontSubstitution PDFFontSubstitutions[] = {
    {"Courier", "Courier New", false, false},
    {"Courier-Bold", "Courier New", true, false},
    {"Courier-BoldOblique", "Courier New", true, true},
    {"Courier-Oblique", "Courier New", false, true},
    {"Helvetica", "Arial", false, false},
    {"Helvetica-Bold", "Arial", true, false},
    {"Helvetica-BoldOblique", "Arial", true, true},
    {"Helvetica-Oblique", "Arial", false, true},
    {"Times-Roman", "Times New Roman", false, false},
    {"Times-Bold", "Times New Roman", true, false},
    {"Times-BoldItalic", "Times New Roman", true, true},
    {"Times-Italic", "Times New Roman", false, true},

    // MS P?(Mincho|Gothic) are the most notable fonts in Japanese PDF files
    // without embedding the glyphs. Sometimes the font names are encoded
    // in Japanese Windows's locale (CP932/Shift_JIS) without space.
    // Most Linux systems don't have the exact font, but for outsourcing
    // fontconfig to find substitutable font in the system, we pass ASCII
    // font names to it.
    {"MS-PGothic", "MS PGothic", false, false},
    {"MS-Gothic", "MS Gothic", false, false},
    {"MS-PMincho", "MS PMincho", false, false},
    {"MS-Mincho", "MS Mincho", false, false},
    // MS PGothic in Shift_JIS encoding.
    {"\x82\x6C\x82\x72\x82\x6F\x83\x53\x83\x56\x83\x62\x83\x4E",
     "MS PGothic", false, false},
    // MS Gothic in Shift_JIS encoding.
    {"\x82\x6C\x82\x72\x83\x53\x83\x56\x83\x62\x83\x4E",
     "MS Gothic", false, false},
    // MS PMincho in Shift_JIS encoding.
    {"\x82\x6C\x82\x72\x82\x6F\x96\xBE\x92\xA9",
     "MS PMincho", false, false},
    // MS Mincho in Shift_JIS encoding.
    {"\x82\x6C\x82\x72\x96\xBE\x92\xA9",
     "MS Mincho", false, false},
};

void* MapFont(struct _FPDF_SYSFONTINFO*, int weight, int italic,
              int charset, int pitch_family, const char* face, int* exact) {
  // Do not attempt to map fonts if pepper is not initialized (for privet local
  // printing).
  // TODO(noamsml): Real font substitution (http://crbug.com/391978)
  if (!pp::Module::Get())
    return NULL;

  pp::BrowserFontDescription description;

  // Pretend the system does not have the Symbol font to force a fallback to
  // the built in Symbol font in CFX_FontMapper::FindSubstFont().
  if (strcmp(face, "Symbol") == 0)
    return NULL;

  if (pitch_family & FXFONT_FF_FIXEDPITCH) {
    description.set_family(PP_BROWSERFONT_TRUSTED_FAMILY_MONOSPACE);
  } else if (pitch_family & FXFONT_FF_ROMAN) {
    description.set_family(PP_BROWSERFONT_TRUSTED_FAMILY_SERIF);
  }

  // Map from the standard PDF fonts to TrueType font names.
  size_t i;
  for (i = 0; i < arraysize(PDFFontSubstitutions); ++i) {
    if (strcmp(face, PDFFontSubstitutions[i].pdf_name) == 0) {
      description.set_face(PDFFontSubstitutions[i].face);
      if (PDFFontSubstitutions[i].bold)
        description.set_weight(PP_BROWSERFONT_TRUSTED_WEIGHT_BOLD);
      if (PDFFontSubstitutions[i].italic)
        description.set_italic(true);
      break;
    }
  }

  if (i == arraysize(PDFFontSubstitutions)) {
    // TODO(kochi): Pass the face in UTF-8. If face is not encoded in UTF-8,
    // convert to UTF-8 before passing.
    description.set_face(face);

    description.set_weight(WeightToBrowserFontTrustedWeight(weight));
    description.set_italic(italic > 0);
  }

  if (!pp::PDF::IsAvailable()) {
    NOTREACHED();
    return NULL;
  }

  PP_Resource font_resource = pp::PDF::GetFontFileWithFallback(
      pp::InstanceHandle(g_last_instance_id),
      &description.pp_font_description(),
      static_cast<PP_PrivateFontCharset>(charset));
  long res_id = font_resource;
  return reinterpret_cast<void*>(res_id);
}

unsigned long GetFontData(struct _FPDF_SYSFONTINFO*, void* font_id,
                          unsigned int table, unsigned char* buffer,
                          unsigned long buf_size) {
  if (!pp::PDF::IsAvailable()) {
    NOTREACHED();
    return 0;
  }

  uint32_t size = buf_size;
  long res_id = reinterpret_cast<long>(font_id);
  if (!pp::PDF::GetFontTableForPrivateFontFile(res_id, table, buffer, &size))
    return 0;
  return size;
}

void DeleteFont(struct _FPDF_SYSFONTINFO*, void* font_id) {
  long res_id = reinterpret_cast<long>(font_id);
  pp::Module::Get()->core()->ReleaseResource(res_id);
}

FPDF_SYSFONTINFO g_font_info = {
  1,
  0,
  EnumFonts,
  MapFont,
  0,
  GetFontData,
  0,
  0,
  DeleteFont
};
#endif  // defined(OS_LINUX)

void OOM_Handler(_OOM_INFO*) {
  // Kill the process.  This is important for security, since the code doesn't
  // NULL-check many memory allocations.  If a malloc fails, returns NULL, and
  // the buffer is then used, it provides a handy mapping of memory starting at
  // address 0 for an attacker to utilize.
  abort();
}

OOM_INFO g_oom_info = {
  1,
  OOM_Handler
};

PDFiumEngine* g_engine_for_unsupported;

void Unsupported_Handler(UNSUPPORT_INFO*, int type) {
  if (!g_engine_for_unsupported) {
    NOTREACHED();
    return;
  }

  g_engine_for_unsupported->UnsupportedFeature(type);
}

UNSUPPORT_INFO g_unsuppored_info = {
  1,
  Unsupported_Handler
};

// Set the destination page size and content area in points based on source
// page rotation and orientation.
//
// |rotated| True if source page is rotated 90 degree or 270 degree.
// |is_src_page_landscape| is true if the source page orientation is landscape.
// |page_size| has the actual destination page size in points.
// |content_rect| has the actual destination page printable area values in
// points.
void SetPageSizeAndContentRect(bool rotated,
                               bool is_src_page_landscape,
                               pp::Size* page_size,
                               pp::Rect* content_rect) {
  bool is_dst_page_landscape = page_size->width() > page_size->height();
  bool page_orientation_mismatched = is_src_page_landscape !=
                                     is_dst_page_landscape;
  bool rotate_dst_page = rotated ^ page_orientation_mismatched;
  if (rotate_dst_page) {
    page_size->SetSize(page_size->height(), page_size->width());
    content_rect->SetRect(content_rect->y(), content_rect->x(),
                          content_rect->height(), content_rect->width());
  }
}

// Calculate the scale factor between |content_rect| and a page of size
// |src_width| x |src_height|.
//
// |scale_to_fit| is true, if we need to calculate the scale factor.
// |content_rect| specifies the printable area of the destination page, with
// origin at left-bottom. Values are in points.
// |src_width| specifies the source page width in points.
// |src_height| specifies the source page height in points.
// |rotated| True if source page is rotated 90 degree or 270 degree.
double CalculateScaleFactor(bool scale_to_fit,
                            const pp::Rect& content_rect,
                            double src_width, double src_height, bool rotated) {
  if (!scale_to_fit || src_width == 0 || src_height == 0)
    return 1.0;

  double actual_source_page_width = rotated ? src_height : src_width;
  double actual_source_page_height = rotated ? src_width : src_height;
  double ratio_x = static_cast<double>(content_rect.width()) /
                   actual_source_page_width;
  double ratio_y = static_cast<double>(content_rect.height()) /
                   actual_source_page_height;
  return std::min(ratio_x, ratio_y);
}

// Compute source clip box boundaries based on the crop box / media box of
// source page and scale factor.
//
// |page| Handle to the source page. Returned by FPDF_LoadPage function.
// |scale_factor| specifies the scale factor that should be applied to source
// clip box boundaries.
// |rotated| True if source page is rotated 90 degree or 270 degree.
// |clip_box| out param to hold the computed source clip box values.
void CalculateClipBoxBoundary(FPDF_PAGE page, double scale_factor, bool rotated,
                              ClipBox* clip_box) {
  if (!FPDFPage_GetCropBox(page, &clip_box->left, &clip_box->bottom,
                           &clip_box->right, &clip_box->top)) {
    if (!FPDFPage_GetMediaBox(page, &clip_box->left, &clip_box->bottom,
                              &clip_box->right, &clip_box->top)) {
      // Make the default size to be letter size (8.5" X 11"). We are just
      // following the PDFium way of handling these corner cases. PDFium always
      // consider US-Letter as the default page size.
      float paper_width = 612;
      float paper_height = 792;
      clip_box->left = 0;
      clip_box->bottom = 0;
      clip_box->right = rotated ? paper_height : paper_width;
      clip_box->top = rotated ? paper_width : paper_height;
    }
  }
  clip_box->left *= scale_factor;
  clip_box->right *= scale_factor;
  clip_box->bottom *= scale_factor;
  clip_box->top *= scale_factor;
}

// Calculate the clip box translation offset for a page that does need to be
// scaled. All parameters are in points.
//
// |content_rect| specifies the printable area of the destination page, with
// origin at left-bottom.
// |source_clip_box| specifies the source clip box positions, relative to
// origin at left-bottom.
// |offset_x| and |offset_y| will contain the final translation offsets for the
// source clip box, relative to origin at left-bottom.
void CalculateScaledClipBoxOffset(const pp::Rect& content_rect,
                                  const ClipBox& source_clip_box,
                                  double* offset_x, double* offset_y) {
  const float clip_box_width = source_clip_box.right - source_clip_box.left;
  const float clip_box_height = source_clip_box.top - source_clip_box.bottom;

  // Center the intended clip region to real clip region.
  *offset_x = (content_rect.width() - clip_box_width) / 2 + content_rect.x() -
              source_clip_box.left;
  *offset_y = (content_rect.height() - clip_box_height) / 2 + content_rect.y() -
              source_clip_box.bottom;
}

// Calculate the clip box offset for a page that does not need to be scaled.
// All parameters are in points.
//
// |content_rect| specifies the printable area of the destination page, with
// origin at left-bottom.
// |rotation| specifies the source page rotation values which are N / 90
// degrees.
// |page_width| specifies the screen destination page width.
// |page_height| specifies the screen destination page height.
// |source_clip_box| specifies the source clip box positions, relative to origin
// at left-bottom.
// |offset_x| and |offset_y| will contain the final translation offsets for the
// source clip box, relative to origin at left-bottom.
void CalculateNonScaledClipBoxOffset(const pp::Rect& content_rect, int rotation,
                                     int page_width, int page_height,
                                     const ClipBox& source_clip_box,
                                     double* offset_x, double* offset_y) {
  // Align the intended clip region to left-top corner of real clip region.
  switch (rotation) {
    case 0:
      *offset_x = -1 * source_clip_box.left;
      *offset_y = page_height - source_clip_box.top;
      break;
    case 1:
      *offset_x = 0;
      *offset_y = -1 * source_clip_box.bottom;
      break;
    case 2:
      *offset_x = page_width - source_clip_box.right;
      *offset_y = 0;
      break;
    case 3:
      *offset_x = page_height - source_clip_box.right;
      *offset_y = page_width - source_clip_box.top;
      break;
    default:
      NOTREACHED();
      break;
  }
}

// Do an in-place transformation of objects on |page|. Translate all objects on
// |page| in |source_clip_box| by (|offset_x|, |offset_y|) and scale them by
// |scale_factor|.
//
// |page| Handle to the page. Returned by FPDF_LoadPage function.
// |source_clip_box| specifies the source clip box positions, relative to
// origin at left-bottom.
// |scale_factor| specifies the scale factor that should be applied to page
// objects.
// |offset_x| and |offset_y| specifies the translation offsets for the page
// objects, relative to origin at left-bottom.

void TransformPageObjects(FPDF_PAGE page, const ClipBox& source_clip_box,
                          const double scale_factor, double offset_x,
                          double offset_y) {
  const int obj_count = FPDFPage_CountObject(page);

  // Create a new clip path.
  FPDF_CLIPPATH clip_path = FPDF_CreateClipPath(
      source_clip_box.left + offset_x, source_clip_box.bottom + offset_y,
      source_clip_box.right + offset_x, source_clip_box.top + offset_y);

  for (int obj_idx = 0; obj_idx < obj_count; ++obj_idx) {
    FPDF_PAGEOBJECT page_obj = FPDFPage_GetObject(page, obj_idx);
    FPDFPageObj_Transform(page_obj, scale_factor, 0, 0, scale_factor,
                          offset_x, offset_y);
    FPDFPageObj_TransformClipPath(page_obj, scale_factor, 0, 0, scale_factor,
                                  offset_x, offset_y);
  }
  FPDFPage_TransformAnnots(page, scale_factor, 0, 0, scale_factor,
                           offset_x, offset_y);
  FPDFPage_GenerateContent(page);

  // Add a extra clip path to the new pdf page here.
  FPDFPage_InsertClipPath(page, clip_path);

  // Destroy the clip path.
  FPDF_DestroyClipPath(clip_path);
}

bool InitializeSDK(void* data) {
  FPDF_InitLibrary(data);

#if defined(OS_LINUX)
  // Font loading doesn't work in the renderer sandbox in Linux.
  FPDF_SetSystemFontInfo(&g_font_info);
#endif

  FSDK_SetOOMHandler(&g_oom_info);
  FSDK_SetUnSpObjProcessHandler(&g_unsuppored_info);

  return true;
}

void ShutdownSDK() {
  FPDF_DestroyLibrary();
}

PDFEngine* PDFEngine::Create(PDFEngine::Client* client) {
  return new PDFiumEngine(client);
}

PDFiumEngine::PDFiumEngine(PDFEngine::Client* client)
    : client_(client),
      current_zoom_(1.0),
      current_rotation_(0),
      doc_loader_(this),
      password_tries_remaining_(0),
      doc_(NULL),
      form_(NULL),
      defer_page_unload_(false),
      selecting_(false),
      next_page_to_search_(-1),
      last_page_to_search_(-1),
      last_character_index_to_search_(-1),
      current_find_index_(-1),
      permissions_(0),
      fpdf_availability_(NULL),
      next_timer_id_(0),
      last_page_mouse_down_(-1),
      first_visible_page_(-1),
      most_visible_page_(-1),
      called_do_document_action_(false),
      render_grayscale_(false),
      progressive_paint_timeout_(0),
      getting_password_(false) {
  find_factory_.Initialize(this);
  password_factory_.Initialize(this);

  file_access_.m_FileLen = 0;
  file_access_.m_GetBlock = &GetBlock;
  file_access_.m_Param = &doc_loader_;

  file_availability_.version = 1;
  file_availability_.IsDataAvail = &IsDataAvail;
  file_availability_.loader = &doc_loader_;

  download_hints_.version = 1;
  download_hints_.AddSegment = &AddSegment;
  download_hints_.loader = &doc_loader_;

  // Initialize FPDF_FORMFILLINFO member variables.  Deriving from this struct
  // allows the static callbacks to be able to cast the FPDF_FORMFILLINFO in
  // callbacks to ourself instead of maintaining a map of them to
  // PDFiumEngine.
  FPDF_FORMFILLINFO::version = 1;
  FPDF_FORMFILLINFO::m_pJsPlatform = this;
  FPDF_FORMFILLINFO::Release = NULL;
  FPDF_FORMFILLINFO::FFI_Invalidate = Form_Invalidate;
  FPDF_FORMFILLINFO::FFI_OutputSelectedRect = Form_OutputSelectedRect;
  FPDF_FORMFILLINFO::FFI_SetCursor = Form_SetCursor;
  FPDF_FORMFILLINFO::FFI_SetTimer = Form_SetTimer;
  FPDF_FORMFILLINFO::FFI_KillTimer = Form_KillTimer;
  FPDF_FORMFILLINFO::FFI_GetLocalTime = Form_GetLocalTime;
  FPDF_FORMFILLINFO::FFI_OnChange = Form_OnChange;
  FPDF_FORMFILLINFO::FFI_GetPage = Form_GetPage;
  FPDF_FORMFILLINFO::FFI_GetCurrentPage = Form_GetCurrentPage;
  FPDF_FORMFILLINFO::FFI_GetRotation = Form_GetRotation;
  FPDF_FORMFILLINFO::FFI_ExecuteNamedAction = Form_ExecuteNamedAction;
  FPDF_FORMFILLINFO::FFI_SetTextFieldFocus = Form_SetTextFieldFocus;
  FPDF_FORMFILLINFO::FFI_DoURIAction = Form_DoURIAction;
  FPDF_FORMFILLINFO::FFI_DoGoToAction = Form_DoGoToAction;

  IPDF_JSPLATFORM::version = 1;
  IPDF_JSPLATFORM::app_alert = Form_Alert;
  IPDF_JSPLATFORM::app_beep = Form_Beep;
  IPDF_JSPLATFORM::app_response = Form_Response;
  IPDF_JSPLATFORM::Doc_getFilePath = Form_GetFilePath;
  IPDF_JSPLATFORM::Doc_mail = Form_Mail;
  IPDF_JSPLATFORM::Doc_print = Form_Print;
  IPDF_JSPLATFORM::Doc_submitForm = Form_SubmitForm;
  IPDF_JSPLATFORM::Doc_gotoPage = Form_GotoPage;
  IPDF_JSPLATFORM::Field_browse = Form_Browse;

  IFSDK_PAUSE::version = 1;
  IFSDK_PAUSE::user = NULL;
  IFSDK_PAUSE::NeedToPauseNow = Pause_NeedToPauseNow;
}

PDFiumEngine::~PDFiumEngine() {
  STLDeleteElements(&pages_);
  if (doc_) {
    if (form_) {
      FORM_DoDocumentAAction(form_, FPDFDOC_AACTION_WC);
      FPDFDOC_ExitFormFillEnviroument(form_);
    }
    FPDF_CloseDocument(doc_);
  }

  if (fpdf_availability_)
    FPDFAvail_Destroy(fpdf_availability_);
}

int PDFiumEngine::GetBlock(void* param, unsigned long position,
                           unsigned char* buffer, unsigned long size) {
  DocumentLoader* loader = static_cast<DocumentLoader*>(param);
  return loader->GetBlock(position, size, buffer);
}

bool PDFiumEngine::IsDataAvail(FX_FILEAVAIL* param,
                               size_t offset, size_t size) {
  PDFiumEngine::FileAvail* file_avail =
      static_cast<PDFiumEngine::FileAvail*>(param);
  return file_avail->loader->IsDataAvailable(offset, size);
}

void PDFiumEngine::AddSegment(FX_DOWNLOADHINTS* param,
                              size_t offset, size_t size) {
  PDFiumEngine::DownloadHints* download_hints =
      static_cast<PDFiumEngine::DownloadHints*>(param);
  return download_hints->loader->RequestData(offset, size);
}

bool PDFiumEngine::New(const char* url) {
  url_ = url;
  headers_ = std::string();
  return true;
}

bool PDFiumEngine::New(const char* url,
                       const char* headers) {
  url_ = url;
  if (!headers)
    headers_ = std::string();
  else
    headers_ = headers;
  return true;
}

void PDFiumEngine::PageOffsetUpdated(const pp::Point& page_offset) {
  page_offset_ = page_offset;
}

void PDFiumEngine::PluginSizeUpdated(const pp::Size& size) {
  CancelPaints();

  plugin_size_ = size;
  CalculateVisiblePages();
}

void PDFiumEngine::ScrolledToXPosition(int position) {
  CancelPaints();

  int old_x = position_.x();
  position_.set_x(position);
  CalculateVisiblePages();
  client_->Scroll(pp::Point(old_x - position, 0));
}

void PDFiumEngine::ScrolledToYPosition(int position) {
  CancelPaints();

  int old_y = position_.y();
  position_.set_y(position);
  CalculateVisiblePages();
  client_->Scroll(pp::Point(0, old_y - position));
}

void PDFiumEngine::PrePaint() {
  for (size_t i = 0; i < progressive_paints_.size(); ++i)
    progressive_paints_[i].painted_ = false;
}

void PDFiumEngine::Paint(const pp::Rect& rect,
                         pp::ImageData* image_data,
                         std::vector<pp::Rect>* ready,
                         std::vector<pp::Rect>* pending) {
  pp::Rect leftover = rect;
  for (size_t i = 0; i < visible_pages_.size(); ++i) {
    int index = visible_pages_[i];
    pp::Rect page_rect = pages_[index]->rect();
    // Convert the current page's rectangle to screen rectangle.  We do this
    // instead of the reverse (converting the dirty rectangle from screen to
    // page coordinates) because then we'd have to convert back to screen
    // coordinates, and the rounding errors sometime leave pixels dirty or even
    // move the text up or down a pixel when zoomed.
    pp::Rect page_rect_in_screen = GetPageScreenRect(index);
    pp::Rect dirty_in_screen = page_rect_in_screen.Intersect(leftover);
    if (dirty_in_screen.IsEmpty())
      continue;

    leftover = leftover.Subtract(dirty_in_screen);

    if (pages_[index]->available()) {
      int progressive = GetProgressiveIndex(index);
      if (progressive != -1 &&
          progressive_paints_[progressive].rect != dirty_in_screen) {
        // The PDFium code can only handle one progressive paint at a time, so
        // queue this up. Previously we used to merge the rects when this
        // happened, but it made scrolling up on complex PDFs very slow since
        // there would be a damaged rect at the top (from scroll) and at the
        // bottom (from toolbar).
        pending->push_back(dirty_in_screen);
        continue;
      }

      if (progressive == -1) {
        progressive = StartPaint(index, dirty_in_screen);
        progressive_paint_timeout_ = kMaxInitialProgressivePaintTimeMs;
      } else {
        progressive_paint_timeout_ = kMaxProgressivePaintTimeMs;
      }

      progressive_paints_[progressive].painted_ = true;
      if (ContinuePaint(progressive, image_data)) {
        FinishPaint(progressive, image_data);
        ready->push_back(dirty_in_screen);
      } else {
        pending->push_back(dirty_in_screen);
      }
    } else {
      PaintUnavailablePage(index, dirty_in_screen, image_data);
      ready->push_back(dirty_in_screen);
    }
  }
}

void PDFiumEngine::PostPaint() {
  for (size_t i = 0; i < progressive_paints_.size(); ++i) {
    if (progressive_paints_[i].painted_)
      continue;

    // This rectangle must have been merged with another one, that's why we
    // weren't asked to paint it. Remove it or otherwise we'll never finish
    // painting.
    FPDF_RenderPage_Close(
        pages_[progressive_paints_[i].page_index]->GetPage());
    FPDFBitmap_Destroy(progressive_paints_[i].bitmap);
    progressive_paints_.erase(progressive_paints_.begin() + i);
    --i;
  }
}

bool PDFiumEngine::HandleDocumentLoad(const pp::URLLoader& loader) {
  password_tries_remaining_ = kMaxPasswordTries;
  return doc_loader_.Init(loader, url_, headers_);
}

pp::Instance* PDFiumEngine::GetPluginInstance() {
  return client_->GetPluginInstance();
}

pp::URLLoader PDFiumEngine::CreateURLLoader() {
  return client_->CreateURLLoader();
}

void PDFiumEngine::AppendPage(PDFEngine* engine, int index) {
  // Unload and delete the blank page before appending.
  pages_[index]->Unload();
  pages_[index]->set_calculated_links(false);
  pp::Size curr_page_size = GetPageSize(index);
  FPDFPage_Delete(doc_, index);
  FPDF_ImportPages(doc_,
                   static_cast<PDFiumEngine*>(engine)->doc(),
                   "1",
                   index);
  pp::Size new_page_size = GetPageSize(index);
  if (curr_page_size != new_page_size)
    LoadPageInfo(true);
  client_->Invalidate(GetPageScreenRect(index));
}

pp::Point PDFiumEngine::GetScrollPosition() {
  return position_;
}

void PDFiumEngine::SetScrollPosition(const pp::Point& position) {
  position_ = position;
}

bool PDFiumEngine::IsProgressiveLoad() {
  return doc_loader_.is_partial_document();
}

void PDFiumEngine::OnPartialDocumentLoaded() {
  file_access_.m_FileLen = doc_loader_.document_size();
  fpdf_availability_ = FPDFAvail_Create(&file_availability_, &file_access_);
  DCHECK(fpdf_availability_);

  // Currently engine does not deal efficiently with some non-linearized files.
  // See http://code.google.com/p/chromium/issues/detail?id=59400
  // To improve user experience we download entire file for non-linearized PDF.
  if (!FPDFAvail_IsLinearized(fpdf_availability_)) {
    doc_loader_.RequestData(0, doc_loader_.document_size());
    return;
  }

  LoadDocument();
}

void PDFiumEngine::OnPendingRequestComplete() {
  if (!doc_ || !form_) {
    LoadDocument();
    return;
  }

  // LoadDocument() will result in |pending_pages_| being reset so there's no
  // need to run the code below in that case.
  bool update_pages = false;
  std::vector<int> still_pending;
  for (size_t i = 0; i < pending_pages_.size(); ++i) {
    if (CheckPageAvailable(pending_pages_[i], &still_pending)) {
      update_pages = true;
      if (IsPageVisible(pending_pages_[i]))
        client_->Invalidate(GetPageScreenRect(pending_pages_[i]));
    }
  }
  pending_pages_.swap(still_pending);
  if (update_pages)
    LoadPageInfo(true);
}

void PDFiumEngine::OnNewDataAvailable() {
  client_->DocumentLoadProgress(doc_loader_.GetAvailableData(),
                                doc_loader_.document_size());
}

void PDFiumEngine::OnDocumentComplete() {
  if (!doc_ || !form_) {
    file_access_.m_FileLen = doc_loader_.document_size();
    LoadDocument();
    return;
  }

  bool need_update = false;
  for (size_t i = 0; i < pages_.size(); ++i) {
    if (pages_[i]->available())
      continue;

    pages_[i]->set_available(true);
    // We still need to call IsPageAvail() even if the whole document is
    // already downloaded.
    FPDFAvail_IsPageAvail(fpdf_availability_, i, &download_hints_);
    need_update = true;
    if (IsPageVisible(i))
      client_->Invalidate(GetPageScreenRect(i));
  }
  if (need_update)
    LoadPageInfo(true);

  FinishLoadingDocument();
}

void PDFiumEngine::FinishLoadingDocument() {
  DCHECK(doc_loader_.IsDocumentComplete() && doc_);
  if (called_do_document_action_)
    return;
  called_do_document_action_ = true;

  // These can only be called now, as the JS might end up needing a page.
  FORM_DoDocumentJSAction(form_);
  FORM_DoDocumentOpenAction(form_);
  if (most_visible_page_ != -1) {
    FPDF_PAGE new_page = pages_[most_visible_page_]->GetPage();
    FORM_DoPageAAction(new_page, form_, FPDFPAGE_AACTION_OPEN);
  }

  if (doc_) // This can only happen if loading |doc_| fails.
    client_->DocumentLoadComplete(pages_.size());
}

void PDFiumEngine::UnsupportedFeature(int type) {
  std::string feature;
  switch (type) {
    case FPDF_UNSP_DOC_XFAFORM:
      feature = "XFA";
      break;
    case FPDF_UNSP_DOC_PORTABLECOLLECTION:
      feature = "Portfolios_Packages";
      break;
    case FPDF_UNSP_DOC_ATTACHMENT:
    case FPDF_UNSP_ANNOT_ATTACHMENT:
      feature = "Attachment";
      break;
    case FPDF_UNSP_DOC_SECURITY:
      feature = "Rights_Management";
      break;
    case FPDF_UNSP_DOC_SHAREDREVIEW:
      feature = "Shared_Review";
      break;
    case FPDF_UNSP_DOC_SHAREDFORM_ACROBAT:
    case FPDF_UNSP_DOC_SHAREDFORM_FILESYSTEM:
    case FPDF_UNSP_DOC_SHAREDFORM_EMAIL:
      feature = "Shared_Form";
      break;
    case FPDF_UNSP_ANNOT_3DANNOT:
      feature = "3D";
      break;
    case FPDF_UNSP_ANNOT_MOVIE:
      feature = "Movie";
      break;
    case FPDF_UNSP_ANNOT_SOUND:
      feature = "Sound";
      break;
    case FPDF_UNSP_ANNOT_SCREEN_MEDIA:
    case FPDF_UNSP_ANNOT_SCREEN_RICHMEDIA:
      feature = "Screen";
      break;
    case FPDF_UNSP_ANNOT_SIG:
      feature = "Digital_Signature";
      break;
  }
  client_->DocumentHasUnsupportedFeature(feature);
}

void PDFiumEngine::ContinueFind(int32_t result) {
  StartFind(current_find_text_.c_str(), !!result);
}

bool PDFiumEngine::HandleEvent(const pp::InputEvent& event) {
  DCHECK(!defer_page_unload_);
  defer_page_unload_ = true;
  bool rv = false;
  switch (event.GetType()) {
    case PP_INPUTEVENT_TYPE_MOUSEDOWN:
      rv = OnMouseDown(pp::MouseInputEvent(event));
      break;
    case PP_INPUTEVENT_TYPE_MOUSEUP:
      rv = OnMouseUp(pp::MouseInputEvent(event));
      break;
    case PP_INPUTEVENT_TYPE_MOUSEMOVE:
      rv = OnMouseMove(pp::MouseInputEvent(event));
      break;
    case PP_INPUTEVENT_TYPE_KEYDOWN:
      rv = OnKeyDown(pp::KeyboardInputEvent(event));
      break;
    case PP_INPUTEVENT_TYPE_KEYUP:
      rv = OnKeyUp(pp::KeyboardInputEvent(event));
      break;
    case PP_INPUTEVENT_TYPE_CHAR:
      rv = OnChar(pp::KeyboardInputEvent(event));
      break;
    default:
      break;
  }

  DCHECK(defer_page_unload_);
  defer_page_unload_ = false;
  for (size_t i = 0; i < deferred_page_unloads_.size(); ++i)
    pages_[deferred_page_unloads_[i]]->Unload();
  deferred_page_unloads_.clear();
  return rv;
}

uint32_t PDFiumEngine::QuerySupportedPrintOutputFormats() {
  if (!HasPermission(PDFEngine::PERMISSION_PRINT_LOW_QUALITY))
    return 0;
  return PP_PRINTOUTPUTFORMAT_PDF;
}

void PDFiumEngine::PrintBegin() {
  FORM_DoDocumentAAction(form_, FPDFDOC_AACTION_WP);
}

pp::Resource PDFiumEngine::PrintPages(
    const PP_PrintPageNumberRange_Dev* page_ranges, uint32_t page_range_count,
    const PP_PrintSettings_Dev& print_settings) {
  if (HasPermission(PDFEngine::PERMISSION_PRINT_HIGH_QUALITY))
    return PrintPagesAsPDF(page_ranges, page_range_count, print_settings);
  else if (HasPermission(PDFEngine::PERMISSION_PRINT_LOW_QUALITY))
    return PrintPagesAsRasterPDF(page_ranges, page_range_count, print_settings);
  return pp::Resource();
}

FPDF_DOCUMENT PDFiumEngine::CreateSinglePageRasterPdf(
    double source_page_width,
    double source_page_height,
    const PP_PrintSettings_Dev& print_settings,
    PDFiumPage* page_to_print) {
  FPDF_DOCUMENT temp_doc = FPDF_CreateNewDocument();
  if (!temp_doc)
    return temp_doc;

  const pp::Size& bitmap_size(page_to_print->rect().size());

  FPDF_PAGE temp_page =
      FPDFPage_New(temp_doc, 0, source_page_width, source_page_height);

  pp::ImageData image = pp::ImageData(client_->GetPluginInstance(),
                                      PP_IMAGEDATAFORMAT_BGRA_PREMUL,
                                      bitmap_size,
                                      false);

  FPDF_BITMAP bitmap = FPDFBitmap_CreateEx(bitmap_size.width(),
                                           bitmap_size.height(),
                                           FPDFBitmap_BGRx,
                                           image.data(),
                                           image.stride());

  // Clear the bitmap
  FPDFBitmap_FillRect(
      bitmap, 0, 0, bitmap_size.width(), bitmap_size.height(), 0xFFFFFFFF);

  pp::Rect page_rect = page_to_print->rect();
  FPDF_RenderPageBitmap(bitmap,
                        page_to_print->GetPrintPage(),
                        page_rect.x(),
                        page_rect.y(),
                        page_rect.width(),
                        page_rect.height(),
                        print_settings.orientation,
                        FPDF_ANNOT | FPDF_PRINTING | FPDF_NO_CATCH);

  double ratio_x = (static_cast<double>(bitmap_size.width()) * kPointsPerInch) /
                   print_settings.dpi;
  double ratio_y =
      (static_cast<double>(bitmap_size.height()) * kPointsPerInch) /
      print_settings.dpi;

  // Add the bitmap to an image object and add the image object to the output
  // page.
  FPDF_PAGEOBJECT temp_img = FPDFPageObj_NewImgeObj(temp_doc);
  FPDFImageObj_SetBitmap(&temp_page, 1, temp_img, bitmap);
  FPDFImageObj_SetMatrix(temp_img, ratio_x, 0, 0, ratio_y, 0, 0);
  FPDFPage_InsertObject(temp_page, temp_img);
  FPDFPage_GenerateContent(temp_page);
  FPDF_ClosePage(temp_page);

  page_to_print->ClosePrintPage();
  FPDFBitmap_Destroy(bitmap);

  return temp_doc;
}

pp::Buffer_Dev PDFiumEngine::PrintPagesAsRasterPDF(
    const PP_PrintPageNumberRange_Dev* page_ranges, uint32_t page_range_count,
    const PP_PrintSettings_Dev& print_settings) {
  if (!page_range_count)
    return pp::Buffer_Dev();

  // If document is not downloaded yet, disable printing.
  if (doc_ && !doc_loader_.IsDocumentComplete())
    return pp::Buffer_Dev();

  FPDF_DOCUMENT output_doc = FPDF_CreateNewDocument();
  if (!output_doc)
    return pp::Buffer_Dev();

  SaveSelectedFormForPrint();

  std::vector<PDFiumPage> pages_to_print;
  // width and height of source PDF pages.
  std::vector<std::pair<double, double> > source_page_sizes;
  // Collect pages to print and sizes of source pages.
  std::vector<uint32_t> page_numbers =
      GetPageNumbersFromPrintPageNumberRange(page_ranges, page_range_count);
  for (size_t i = 0; i < page_numbers.size(); ++i) {
    uint32_t page_number = page_numbers[i];
    FPDF_PAGE pdf_page = FPDF_LoadPage(doc_, page_number);
    double source_page_width = FPDF_GetPageWidth(pdf_page);
    double source_page_height = FPDF_GetPageHeight(pdf_page);
    source_page_sizes.push_back(std::make_pair(source_page_width,
                                               source_page_height));

    int width_in_pixels = ConvertUnit(source_page_width,
                                      static_cast<int>(kPointsPerInch),
                                      print_settings.dpi);
    int height_in_pixels = ConvertUnit(source_page_height,
                                       static_cast<int>(kPointsPerInch),
                                       print_settings.dpi);

    pp::Rect rect(width_in_pixels, height_in_pixels);
    pages_to_print.push_back(PDFiumPage(this, page_number, rect, true));
    FPDF_ClosePage(pdf_page);
  }

#if defined(OS_LINUX)
  g_last_instance_id = client_->GetPluginInstance()->pp_instance();
#endif

  size_t i = 0;
  for (; i < pages_to_print.size(); ++i) {
    double source_page_width = source_page_sizes[i].first;
    double source_page_height = source_page_sizes[i].second;

    // Use temp_doc to compress image by saving PDF to buffer.
    FPDF_DOCUMENT temp_doc = CreateSinglePageRasterPdf(source_page_width,
                                                       source_page_height,
                                                       print_settings,
                                                       &pages_to_print[i]);

    if (!temp_doc)
      break;

    pp::Buffer_Dev buffer = GetFlattenedPrintData(temp_doc);
    FPDF_CloseDocument(temp_doc);

    PDFiumMemBufferFileRead file_read(buffer.data(), buffer.size());
    temp_doc = FPDF_LoadCustomDocument(&file_read, NULL);

    FPDF_BOOL imported = FPDF_ImportPages(output_doc, temp_doc, "1", i);
    FPDF_CloseDocument(temp_doc);
    if (!imported)
      break;
  }

  pp::Buffer_Dev buffer;
  if (i == pages_to_print.size()) {
    FPDF_CopyViewerPreferences(output_doc, doc_);
    FitContentsToPrintableAreaIfRequired(output_doc, print_settings);
    // Now flatten all the output pages.
    buffer = GetFlattenedPrintData(output_doc);
  }
  FPDF_CloseDocument(output_doc);
  return buffer;
}

pp::Buffer_Dev PDFiumEngine::GetFlattenedPrintData(const FPDF_DOCUMENT& doc) {
  int page_count = FPDF_GetPageCount(doc);
  bool flatten_succeeded = true;
  for (int i = 0; i < page_count; ++i) {
    FPDF_PAGE page = FPDF_LoadPage(doc, i);
    DCHECK(page);
    if (page) {
      int flatten_ret = FPDFPage_Flatten(page, FLAT_PRINT);
      FPDF_ClosePage(page);
      if (flatten_ret == FLATTEN_FAIL) {
        flatten_succeeded = false;
        break;
      }
    } else {
      flatten_succeeded = false;
      break;
    }
  }
  if (!flatten_succeeded) {
    FPDF_CloseDocument(doc);
    return pp::Buffer_Dev();
  }

  pp::Buffer_Dev buffer;
  PDFiumMemBufferFileWrite output_file_write;
  if (FPDF_SaveAsCopy(doc, &output_file_write, 0)) {
    buffer = pp::Buffer_Dev(
        client_->GetPluginInstance(), output_file_write.size());
    if (!buffer.is_null()) {
      memcpy(buffer.data(), output_file_write.buffer().c_str(),
             output_file_write.size());
    }
  }
  return buffer;
}

pp::Buffer_Dev PDFiumEngine::PrintPagesAsPDF(
    const PP_PrintPageNumberRange_Dev* page_ranges, uint32_t page_range_count,
    const PP_PrintSettings_Dev& print_settings) {
  if (!page_range_count)
    return pp::Buffer_Dev();

  DCHECK(doc_);
  FPDF_DOCUMENT output_doc = FPDF_CreateNewDocument();
  if (!output_doc)
    return pp::Buffer_Dev();

  SaveSelectedFormForPrint();

  std::string page_number_str;
  for (uint32_t index = 0; index < page_range_count; ++index) {
    if (!page_number_str.empty())
      page_number_str.append(",");
    page_number_str.append(
        base::IntToString(page_ranges[index].first_page_number + 1));
    if (page_ranges[index].first_page_number !=
            page_ranges[index].last_page_number) {
      page_number_str.append("-");
      page_number_str.append(
          base::IntToString(page_ranges[index].last_page_number + 1));
    }
  }

  std::vector<uint32_t> page_numbers =
      GetPageNumbersFromPrintPageNumberRange(page_ranges, page_range_count);
  for (size_t i = 0; i < page_numbers.size(); ++i) {
    uint32_t page_number = page_numbers[i];
    pages_[page_number]->GetPage();
    if (!IsPageVisible(page_numbers[i]))
      pages_[page_number]->Unload();
  }

  FPDF_CopyViewerPreferences(output_doc, doc_);
  if (!FPDF_ImportPages(output_doc, doc_, page_number_str.c_str(), 0)) {
    FPDF_CloseDocument(output_doc);
    return pp::Buffer_Dev();
  }

  FitContentsToPrintableAreaIfRequired(output_doc, print_settings);

  // Now flatten all the output pages.
  pp::Buffer_Dev buffer = GetFlattenedPrintData(output_doc);
  FPDF_CloseDocument(output_doc);
  return buffer;
}

void PDFiumEngine::FitContentsToPrintableAreaIfRequired(
    const FPDF_DOCUMENT& doc, const PP_PrintSettings_Dev& print_settings) {
  // Check to see if we need to fit pdf contents to printer paper size.
  if (print_settings.print_scaling_option !=
          PP_PRINTSCALINGOPTION_SOURCE_SIZE) {
    int num_pages = FPDF_GetPageCount(doc);
    // In-place transformation is more efficient than creating a new
    // transformed document from the source document. Therefore, transform
    // every page to fit the contents in the selected printer paper.
    for (int i = 0; i < num_pages; ++i) {
      FPDF_PAGE page = FPDF_LoadPage(doc, i);
      TransformPDFPageForPrinting(page, print_settings);
      FPDF_ClosePage(page);
    }
  }
}

void PDFiumEngine::SaveSelectedFormForPrint() {
  FORM_ForceToKillFocus(form_);
  client_->FormTextFieldFocusChange(false);
}

void PDFiumEngine::PrintEnd() {
  FORM_DoDocumentAAction(form_, FPDFDOC_AACTION_DP);
}

PDFiumPage::Area PDFiumEngine::GetCharIndex(
    const pp::MouseInputEvent& event, int* page_index,
    int* char_index, PDFiumPage::LinkTarget* target) {
  // First figure out which page this is in.
  pp::Point mouse_point = event.GetPosition();
  pp::Point point(
      static_cast<int>((mouse_point.x() + position_.x()) / current_zoom_),
      static_cast<int>((mouse_point.y() + position_.y()) / current_zoom_));
  return GetCharIndex(point, page_index, char_index, target);
}

PDFiumPage::Area PDFiumEngine::GetCharIndex(
    const pp::Point& point,
    int* page_index,
    int* char_index,
    PDFiumPage::LinkTarget* target) {
  int page = -1;
  for (size_t i = 0; i < visible_pages_.size(); ++i) {
    if (pages_[visible_pages_[i]]->rect().Contains(point)) {
      page = visible_pages_[i];
      break;
    }
  }
  if (page == -1)
    return PDFiumPage::NONSELECTABLE_AREA;

  // If the page hasn't finished rendering, calling into the page sometimes
  // leads to hangs.
  for (size_t i = 0; i < progressive_paints_.size(); ++i) {
    if (progressive_paints_[i].page_index == page)
      return PDFiumPage::NONSELECTABLE_AREA;
  }

  *page_index = page;
  return pages_[page]->GetCharIndex(point, current_rotation_, char_index,
                                    target);
}

bool PDFiumEngine::OnMouseDown(const pp::MouseInputEvent& event) {
  if (event.GetButton() != PP_INPUTEVENT_MOUSEBUTTON_LEFT)
    return false;

  SelectionChangeInvalidator selection_invalidator(this);
  selection_.clear();

  int page_index = -1;
  int char_index = -1;
  PDFiumPage::LinkTarget target;
  PDFiumPage::Area area = GetCharIndex(event, &page_index,
                                       &char_index, &target);
  if (area == PDFiumPage::WEBLINK_AREA) {
    bool open_in_new_tab = !!(event.GetModifiers() & kDefaultKeyModifier);
    client_->NavigateTo(target.url, open_in_new_tab);
    client_->FormTextFieldFocusChange(false);
    return true;
  }

  if (area == PDFiumPage::DOCLINK_AREA) {
    client_->ScrollToPage(target.page);
    client_->FormTextFieldFocusChange(false);
    return true;
  }

  if (page_index != -1) {
    last_page_mouse_down_ = page_index;
    double page_x, page_y;
    pp::Point point = event.GetPosition();
    DeviceToPage(page_index, point.x(), point.y(), &page_x, &page_y);

    FORM_OnLButtonDown(form_, pages_[page_index]->GetPage(), 0, page_x, page_y);
    int control = FPDPage_HasFormFieldAtPoint(
        form_, pages_[page_index]->GetPage(), page_x, page_y);
    if (control > FPDF_FORMFIELD_UNKNOWN) {  // returns -1 sometimes...
      client_->FormTextFieldFocusChange(control == FPDF_FORMFIELD_TEXTFIELD ||
          control == FPDF_FORMFIELD_COMBOBOX);
      return true;  // Return now before we get into the selection code.
    }
  }

  client_->FormTextFieldFocusChange(false);

  if (area != PDFiumPage::TEXT_AREA)
    return true;  // Return true so WebKit doesn't do its own highlighting.

  if (event.GetClickCount() == 1) {
    OnSingleClick(page_index, char_index);
  } else if (event.GetClickCount() == 2 ||
             event.GetClickCount() == 3) {
    OnMultipleClick(event.GetClickCount(), page_index, char_index);
  }

  return true;
}

void PDFiumEngine::OnSingleClick(int page_index, int char_index) {
  selecting_ = true;
  selection_.push_back(PDFiumRange(pages_[page_index], char_index, 0));
}

void PDFiumEngine::OnMultipleClick(int click_count,
                                   int page_index,
                                   int char_index) {
  // It would be more efficient if the SDK could support finding a space, but
  // now it doesn't.
  int start_index = char_index;
  do {
    base::char16 cur = pages_[page_index]->GetCharAtIndex(start_index);
    // For double click, we want to select one word so we look for whitespace
    // boundaries.  For triple click, we want the whole line.
    if (cur == '\n' || (click_count == 2 && (cur == ' ' || cur == '\t')))
      break;
  } while (--start_index >= 0);
  if (start_index)
    start_index++;

  int end_index = char_index;
  int total = pages_[page_index]->GetCharCount();
  while (end_index++ <= total) {
    base::char16 cur = pages_[page_index]->GetCharAtIndex(end_index);
    if (cur == '\n' || (click_count == 2 && (cur == ' ' || cur == '\t')))
      break;
  }

  selection_.push_back(PDFiumRange(
      pages_[page_index], start_index, end_index - start_index));
}

bool PDFiumEngine::OnMouseUp(const pp::MouseInputEvent& event) {
  if (event.GetButton() != PP_INPUTEVENT_MOUSEBUTTON_LEFT)
    return false;

  int page_index = -1;
  int char_index = -1;
  GetCharIndex(event, &page_index, &char_index, NULL);
  if (page_index != -1) {
    double page_x, page_y;
    pp::Point point = event.GetPosition();
    DeviceToPage(page_index, point.x(), point.y(), &page_x, &page_y);
    FORM_OnLButtonUp(
        form_, pages_[page_index]->GetPage(), 0, page_x, page_y);
  }

  if (!selecting_)
    return false;

  selecting_ = false;
  return true;
}

bool PDFiumEngine::OnMouseMove(const pp::MouseInputEvent& event) {
  int page_index = -1;
  int char_index = -1;
  PDFiumPage::Area area = GetCharIndex(event, &page_index, &char_index, NULL);
  if (!selecting_) {
    PP_CursorType_Dev cursor;
    switch (area) {
      case PDFiumPage::TEXT_AREA:
        cursor = PP_CURSORTYPE_IBEAM;
        break;
      case PDFiumPage::WEBLINK_AREA:
      case PDFiumPage::DOCLINK_AREA:
        cursor = PP_CURSORTYPE_HAND;
        break;
      case PDFiumPage::NONSELECTABLE_AREA:
      default:
        cursor = PP_CURSORTYPE_POINTER;
        break;
    }

    if (page_index != -1) {
      double page_x, page_y;
      pp::Point point = event.GetPosition();
      DeviceToPage(page_index, point.x(), point.y(), &page_x, &page_y);

      FORM_OnMouseMove(form_, pages_[page_index]->GetPage(), 0, page_x, page_y);
      int control = FPDPage_HasFormFieldAtPoint(
          form_, pages_[page_index]->GetPage(), page_x, page_y);
      switch (control) {
        case FPDF_FORMFIELD_PUSHBUTTON:
        case FPDF_FORMFIELD_CHECKBOX:
        case FPDF_FORMFIELD_RADIOBUTTON:
        case FPDF_FORMFIELD_COMBOBOX:
        case FPDF_FORMFIELD_LISTBOX:
          cursor = PP_CURSORTYPE_HAND;
          break;
        case FPDF_FORMFIELD_TEXTFIELD:
          cursor = PP_CURSORTYPE_IBEAM;
          break;
        default:
          break;
      }
    }

    client_->UpdateCursor(cursor);
    pp::Point point = event.GetPosition();
    std::string url = GetLinkAtPosition(event.GetPosition());
    if (url != link_under_cursor_) {
      link_under_cursor_ = url;
      pp::PDF::SetLinkUnderCursor(GetPluginInstance(), url.c_str());
    }
    // No need to swallow the event, since this might interfere with the
    // scrollbars if the user is dragging them.
    return false;
  }

  // We're selecting but right now we're not over text, so don't change the
  // current selection.
  if (area != PDFiumPage::TEXT_AREA && area != PDFiumPage::WEBLINK_AREA &&
      area != PDFiumPage::DOCLINK_AREA) {
    return false;
  }

  SelectionChangeInvalidator selection_invalidator(this);

  // Check if the user has descreased their selection area and we need to remove
  // pages from selection_.
  for (size_t i = 0; i < selection_.size(); ++i) {
    if (selection_[i].page_index() == page_index) {
      // There should be no other pages after this.
      selection_.erase(selection_.begin() + i + 1, selection_.end());
      break;
    }
  }

  if (selection_.size() == 0)
    return false;

  int last = selection_.size() - 1;
  if (selection_[last].page_index() == page_index) {
    // Selecting within a page.
    int count;
    if (char_index >= selection_[last].char_index()) {
      // Selecting forward.
      count = char_index - selection_[last].char_index() + 1;
    } else {
      count = char_index - selection_[last].char_index() - 1;
    }
    selection_[last].SetCharCount(count);
  } else if (selection_[last].page_index() < page_index) {
    // Selecting into the next page.

    // First make sure that there are no gaps in selection, i.e. if mousedown on
    // page one but we only get mousemove over page three, we want page two.
    for (int i = selection_[last].page_index() + 1; i < page_index; ++i) {
      selection_.push_back(PDFiumRange(pages_[i], 0,
                           pages_[i]->GetCharCount()));
    }

    int count = pages_[selection_[last].page_index()]->GetCharCount();
    selection_[last].SetCharCount(count - selection_[last].char_index());
    selection_.push_back(PDFiumRange(pages_[page_index], 0, char_index));
  } else {
    // Selecting into the previous page.
    selection_[last].SetCharCount(-selection_[last].char_index());

    // First make sure that there are no gaps in selection, i.e. if mousedown on
    // page three but we only get mousemove over page one, we want page two.
    for (int i = selection_[last].page_index() - 1; i > page_index; --i) {
      selection_.push_back(PDFiumRange(pages_[i], 0,
                           pages_[i]->GetCharCount()));
    }

    int count = pages_[page_index]->GetCharCount();
    selection_.push_back(
        PDFiumRange(pages_[page_index], count, count - char_index));
  }

  return true;
}

bool PDFiumEngine::OnKeyDown(const pp::KeyboardInputEvent& event) {
  if (last_page_mouse_down_ == -1)
    return false;

  bool rv = !!FORM_OnKeyDown(
      form_, pages_[last_page_mouse_down_]->GetPage(),
      event.GetKeyCode(), event.GetModifiers());

  if (event.GetKeyCode() == ui::VKEY_BACK ||
      event.GetKeyCode() == ui::VKEY_ESCAPE) {
    // Chrome doesn't send char events for backspace or escape keys, see
    // PlatformKeyboardEventBuilder::isCharacterKey() and
    // http://chrome-corpsvn.mtv.corp.google.com/viewvc?view=rev&root=chrome&revision=31805
    // for more information.  So just fake one since PDFium uses it.
    std::string str;
    str.push_back(event.GetKeyCode());
    pp::KeyboardInputEvent synthesized(pp::KeyboardInputEvent(
        client_->GetPluginInstance(),
        PP_INPUTEVENT_TYPE_CHAR,
        event.GetTimeStamp(),
        event.GetModifiers(),
        event.GetKeyCode(),
        str));
    OnChar(synthesized);
  }

  return rv;
}

bool PDFiumEngine::OnKeyUp(const pp::KeyboardInputEvent& event) {
  if (last_page_mouse_down_ == -1)
    return false;

  return !!FORM_OnKeyUp(
      form_, pages_[last_page_mouse_down_]->GetPage(),
      event.GetKeyCode(), event.GetModifiers());
}

bool PDFiumEngine::OnChar(const pp::KeyboardInputEvent& event) {
  if (last_page_mouse_down_ == -1)
    return false;

  base::string16 str = base::UTF8ToUTF16(event.GetCharacterText().AsString());
  return !!FORM_OnChar(
      form_, pages_[last_page_mouse_down_]->GetPage(),
      str[0],
      event.GetModifiers());
}

void PDFiumEngine::StartFind(const char* text, bool case_sensitive) {
  // We can get a call to StartFind before we have any page information (i.e.
  // before the first call to LoadDocument has happened). Handle this case.
  if (pages_.empty())
    return;

  bool first_search = false;
  int character_to_start_searching_from = 0;
  if (current_find_text_ != text) {  // First time we search for this text.
    first_search = true;
    std::vector<PDFiumRange> old_selection = selection_;
    StopFind();
    current_find_text_ = text;

    if (old_selection.empty()) {
      // Start searching from the beginning of the document.
      next_page_to_search_ = 0;
      last_page_to_search_ = pages_.size() - 1;
      last_character_index_to_search_ = -1;
    } else {
      // There's a current selection, so start from it.
      next_page_to_search_ = old_selection[0].page_index();
      last_character_index_to_search_ = old_selection[0].char_index();
      character_to_start_searching_from = old_selection[0].char_index();
      last_page_to_search_ = next_page_to_search_;
    }
  }

  int current_page = next_page_to_search_;

  if (pages_[current_page]->available()) {
    base::string16 str = base::UTF8ToUTF16(text);
    // Don't use PDFium to search for now, since it doesn't support unicode text.
    // Leave the code for now to avoid bit-rot, in case it's fixed later.
    if (0) {
      SearchUsingPDFium(
          str, case_sensitive, first_search, character_to_start_searching_from,
          current_page);
    } else {
      SearchUsingICU(
          str, case_sensitive, first_search, character_to_start_searching_from,
          current_page);
    }

    if (!IsPageVisible(current_page))
      pages_[current_page]->Unload();
  }

  if (next_page_to_search_ != last_page_to_search_ ||
      (first_search && last_character_index_to_search_ != -1)) {
    ++next_page_to_search_;
  }

  if (next_page_to_search_ == static_cast<int>(pages_.size()))
    next_page_to_search_ = 0;
  // If there's only one page in the document and we start searching midway,
  // then we'll want to search the page one more time.
  bool end_of_search =
      next_page_to_search_ == last_page_to_search_ &&
      // Only one page but didn't start midway.
      ((pages_.size() == 1 && last_character_index_to_search_ == -1) ||
       // Started midway, but only 1 page and we already looped around.
       (pages_.size() == 1 && !first_search) ||
       // Started midway, and we've just looped around.
       (pages_.size() > 1 && current_page == next_page_to_search_));

  if (end_of_search) {
    // Send the final notification.
    client_->NotifyNumberOfFindResultsChanged(find_results_.size(), true);
  } else {
    pp::CompletionCallback callback =
        find_factory_.NewCallback(&PDFiumEngine::ContinueFind);
    pp::Module::Get()->core()->CallOnMainThread(
        0, callback, case_sensitive ? 1 : 0);
  }
}

void PDFiumEngine::SearchUsingPDFium(const base::string16& term,
                                     bool case_sensitive,
                                     bool first_search,
                                     int character_to_start_searching_from,
                                     int current_page) {
  // Find all the matches in the current page.
  unsigned long flags = case_sensitive ? FPDF_MATCHCASE : 0;
  FPDF_SCHHANDLE find = FPDFText_FindStart(
      pages_[current_page]->GetTextPage(),
      reinterpret_cast<const unsigned short*>(term.c_str()),
      flags, character_to_start_searching_from);

  // Note: since we search one page at a time, we don't find matches across
  // page boundaries.  We could do this manually ourself, but it seems low
  // priority since Reader itself doesn't do it.
  while (FPDFText_FindNext(find)) {
    PDFiumRange result(pages_[current_page],
                       FPDFText_GetSchResultIndex(find),
                       FPDFText_GetSchCount(find));

    if (!first_search &&
        last_character_index_to_search_ != -1 &&
        result.page_index() == last_page_to_search_ &&
        result.char_index() >= last_character_index_to_search_) {
      break;
    }

    AddFindResult(result);
  }

  FPDFText_FindClose(find);
}

void PDFiumEngine::SearchUsingICU(const base::string16& term,
                                  bool case_sensitive,
                                  bool first_search,
                                  int character_to_start_searching_from,
                                  int current_page) {
  base::string16 page_text;
  int text_length = pages_[current_page]->GetCharCount();
  if (character_to_start_searching_from) {
    text_length -= character_to_start_searching_from;
  } else if (!first_search &&
             last_character_index_to_search_ != -1 &&
             current_page == last_page_to_search_) {
    text_length = last_character_index_to_search_;
  }
  if (text_length <= 0)
    return;
  unsigned short* data =
      reinterpret_cast<unsigned short*>(WriteInto(&page_text, text_length + 1));
  FPDFText_GetText(pages_[current_page]->GetTextPage(),
                   character_to_start_searching_from,
                   text_length,
                   data);
  std::vector<PDFEngine::Client::SearchStringResult> results;
  client_->SearchString(
      page_text.c_str(), term.c_str(), case_sensitive, &results);
  for (size_t i = 0; i < results.size(); ++i) {
    // Need to map the indexes from the page text, which may have generated
    // characters like space etc, to character indices from the page.
    int temp_start = results[i].start_index + character_to_start_searching_from;
    int start = FPDFText_GetCharIndexFromTextIndex(
        pages_[current_page]->GetTextPage(), temp_start);
    int end = FPDFText_GetCharIndexFromTextIndex(
        pages_[current_page]->GetTextPage(),
        temp_start + results[i].length);
    AddFindResult(PDFiumRange(pages_[current_page], start, end - start));
  }
}

void PDFiumEngine::AddFindResult(const PDFiumRange& result) {
  // Figure out where to insert the new location, since we could have
  // started searching midway and now we wrapped.
  size_t i;
  int page_index = result.page_index();
  int char_index = result.char_index();
  for (i = 0; i < find_results_.size(); ++i) {
    if (find_results_[i].page_index() > page_index ||
        (find_results_[i].page_index() == page_index &&
         find_results_[i].char_index() > char_index)) {
      break;
    }
  }
  find_results_.insert(find_results_.begin() + i, result);
  UpdateTickMarks();

  if (current_find_index_ == -1) {
    // Select the first match.
    SelectFindResult(true);
  } else if (static_cast<int>(i) <= current_find_index_) {
    // Update the current match index
    current_find_index_++;
    client_->NotifySelectedFindResultChanged(current_find_index_);
  }
  client_->NotifyNumberOfFindResultsChanged(find_results_.size(), false);
}

bool PDFiumEngine::SelectFindResult(bool forward) {
  if (find_results_.empty()) {
    NOTREACHED();
    return false;
  }

  SelectionChangeInvalidator selection_invalidator(this);

  // Move back/forward through the search locations we previously found.
  if (forward) {
    if (++current_find_index_ == static_cast<int>(find_results_.size()))
      current_find_index_ = 0;
  } else {
    if (--current_find_index_ < 0) {
      current_find_index_ = find_results_.size() - 1;
    }
  }

  // Update the selection before telling the client to scroll, since it could
  // paint then.
  selection_.clear();
  selection_.push_back(find_results_[current_find_index_]);

  // If the result is not in view, scroll to it.
  size_t i;
  pp::Rect bounding_rect;
  pp::Rect visible_rect = GetVisibleRect();
  // Use zoom of 1.0 since visible_rect is without zoom.
  std::vector<pp::Rect> rects = find_results_[current_find_index_].
      GetScreenRects(pp::Point(), 1.0, current_rotation_);
  for (i = 0; i < rects.size(); ++i)
    bounding_rect = bounding_rect.Union(rects[i]);
  if (!visible_rect.Contains(bounding_rect)) {
    pp::Point center = bounding_rect.CenterPoint();
    // Make the page centered.
    int new_y = static_cast<int>(center.y() * current_zoom_) -
                static_cast<int>(visible_rect.height() * current_zoom_ / 2);
    if (new_y < 0)
      new_y = 0;
    client_->ScrollToY(new_y);

    // Only move horizontally if it's not visible.
    if (center.x() < visible_rect.x() || center.x() > visible_rect.right()) {
      int new_x = static_cast<int>(center.x()  * current_zoom_) -
                  static_cast<int>(visible_rect.width() * current_zoom_ / 2);
      if (new_x < 0)
        new_x = 0;
      client_->ScrollToX(new_x);
    }
  }

  client_->NotifySelectedFindResultChanged(current_find_index_);

  return true;
}

void PDFiumEngine::StopFind() {
  SelectionChangeInvalidator selection_invalidator(this);

  selection_.clear();
  selecting_ = false;
  find_results_.clear();
  next_page_to_search_ = -1;
  last_page_to_search_ = -1;
  last_character_index_to_search_ = -1;
  current_find_index_ = -1;
  current_find_text_.clear();
  UpdateTickMarks();
  find_factory_.CancelAll();
}

void PDFiumEngine::UpdateTickMarks() {
  std::vector<pp::Rect> tickmarks;
  for (size_t i = 0; i < find_results_.size(); ++i) {
    pp::Rect rect;
    // Always use an origin of 0,0 since scroll positions don't affect tickmark.
    std::vector<pp::Rect> rects = find_results_[i].GetScreenRects(
      pp::Point(0, 0), current_zoom_, current_rotation_);
    for (size_t j = 0; j < rects.size(); ++j)
      rect = rect.Union(rects[j]);
    tickmarks.push_back(rect);
  }

  client_->UpdateTickMarks(tickmarks);
}

void PDFiumEngine::ZoomUpdated(double new_zoom_level) {
  CancelPaints();

  current_zoom_ = new_zoom_level;

  CalculateVisiblePages();
  UpdateTickMarks();
}

void PDFiumEngine::RotateClockwise() {
  current_rotation_ = (current_rotation_ + 1) % 4;
  InvalidateAllPages();
}

void PDFiumEngine::RotateCounterclockwise() {
  current_rotation_ = (current_rotation_ - 1) % 4;
  InvalidateAllPages();
}

void PDFiumEngine::InvalidateAllPages() {
  selection_.clear();
  find_results_.clear();

  CancelPaints();
  LoadPageInfo(true);
  UpdateTickMarks();
  client_->Invalidate(pp::Rect(plugin_size_));
}

std::string PDFiumEngine::GetSelectedText() {
  base::string16 result;
  for (size_t i = 0; i < selection_.size(); ++i) {
    if (i > 0 &&
        selection_[i - 1].page_index() > selection_[i].page_index()) {
      result = selection_[i].GetText() + result;
    } else {
      result.append(selection_[i].GetText());
    }
  }

  return base::UTF16ToUTF8(result);
}

std::string PDFiumEngine::GetLinkAtPosition(const pp::Point& point) {
  int temp;
  PDFiumPage::LinkTarget target;
  PDFiumPage::Area area = GetCharIndex(point, &temp, &temp, &target);
  if (area == PDFiumPage::WEBLINK_AREA)
    return target.url;
  return std::string();
}

bool PDFiumEngine::IsSelecting() {
  return selecting_;
}

bool PDFiumEngine::HasPermission(DocumentPermission permission) const {
  switch (permission) {
    case PERMISSION_COPY:
      return (permissions_ & kPDFPermissionCopyMask) != 0;
    case PERMISSION_COPY_ACCESSIBLE:
      return (permissions_ & kPDFPermissionCopyAccessibleMask) != 0;
    case PERMISSION_PRINT_LOW_QUALITY:
      return (permissions_ & kPDFPermissionPrintLowQualityMask) != 0;
    case PERMISSION_PRINT_HIGH_QUALITY:
      return (permissions_ & kPDFPermissionPrintLowQualityMask) != 0 &&
             (permissions_ & kPDFPermissionPrintHighQualityMask) != 0;
    default:
      return true;
  };
}

void PDFiumEngine::SelectAll() {
  SelectionChangeInvalidator selection_invalidator(this);

  selection_.clear();
  for (size_t i = 0; i < pages_.size(); ++i)
    if (pages_[i]->available()) {
      selection_.push_back(PDFiumRange(pages_[i], 0,
                           pages_[i]->GetCharCount()));
    }
}

int PDFiumEngine::GetNumberOfPages() {
  return pages_.size();
}

int PDFiumEngine::GetNamedDestinationPage(const std::string& destination) {
  // Look for the destination.
  FPDF_DEST dest = FPDF_GetNamedDestByName(doc_, destination.c_str());
  if (!dest) {
    // Look for a bookmark with the same name.
    base::string16 destination_wide = base::UTF8ToUTF16(destination);
    FPDF_WIDESTRING destination_pdf_wide =
        reinterpret_cast<FPDF_WIDESTRING>(destination_wide.c_str());
    FPDF_BOOKMARK bookmark = FPDFBookmark_Find(doc_, destination_pdf_wide);
    if (!bookmark)
      return -1;
    dest = FPDFBookmark_GetDest(doc_, bookmark);
  }
  return dest ? FPDFDest_GetPageIndex(doc_, dest) : -1;
}

int PDFiumEngine::GetFirstVisiblePage() {
  CalculateVisiblePages();
  return first_visible_page_;
}

int PDFiumEngine::GetMostVisiblePage() {
  CalculateVisiblePages();
  return most_visible_page_;
}

pp::Rect PDFiumEngine::GetPageRect(int index) {
  pp::Rect rc(pages_[index]->rect());
  rc.Inset(-kPageShadowLeft, -kPageShadowTop,
           -kPageShadowRight, -kPageShadowBottom);
  return rc;
}

pp::Rect PDFiumEngine::GetPageContentsRect(int index) {
  return GetScreenRect(pages_[index]->rect());
}

void PDFiumEngine::PaintThumbnail(pp::ImageData* image_data, int index) {
  FPDF_BITMAP bitmap = FPDFBitmap_CreateEx(
      image_data->size().width(), image_data->size().height(),
      FPDFBitmap_BGRx, image_data->data(), image_data->stride());

  if (pages_[index]->available()) {
    FPDFBitmap_FillRect(bitmap, 0, 0, image_data->size().width(),
                        image_data->size().height(), 0xFFFFFFFF);

    FPDF_RenderPageBitmap(
        bitmap, pages_[index]->GetPage(), 0, 0, image_data->size().width(),
        image_data->size().height(), 0, GetRenderingFlags());
  } else {
    FPDFBitmap_FillRect(bitmap, 0, 0, image_data->size().width(),
                        image_data->size().height(), kPendingPageColor);
  }

  FPDFBitmap_Destroy(bitmap);
}

void PDFiumEngine::SetGrayscale(bool grayscale) {
  render_grayscale_ = grayscale;
}

void PDFiumEngine::OnCallback(int id) {
  if (!timers_.count(id))
    return;

  timers_[id].second(id);
  if (timers_.count(id))  // The callback might delete the timer.
    client_->ScheduleCallback(id, timers_[id].first);
}

std::string PDFiumEngine::GetPageAsJSON(int index) {
  if (!(HasPermission(PERMISSION_COPY) ||
        HasPermission(PERMISSION_COPY_ACCESSIBLE))) {
    return "{}";
  }

  if (index < 0 || static_cast<size_t>(index) > pages_.size() - 1)
    return "{}";

  // TODO(thestig) Remove after debugging http://crbug.com/402035
  CHECK(pages_[index]);
  scoped_ptr<base::Value> node(
      pages_[index]->GetAccessibleContentAsValue(current_rotation_));
  std::string page_json;
  base::JSONWriter::Write(node.get(), &page_json);
  return page_json;
}

bool PDFiumEngine::GetPrintScaling() {
  return !!FPDF_VIEWERREF_GetPrintScaling(doc_);
}

void PDFiumEngine::AppendBlankPages(int num_pages) {
  DCHECK(num_pages != 0);

  if (!doc_)
    return;

  selection_.clear();
  pending_pages_.clear();

  // Delete all pages except the first one.
  while (pages_.size() > 1) {
    delete pages_.back();
    pages_.pop_back();
    FPDFPage_Delete(doc_, pages_.size());
  }

  // Calculate document size and all page sizes.
  std::vector<pp::Rect> page_rects;
  pp::Size page_size = GetPageSize(0);
  page_size.Enlarge(kPageShadowLeft + kPageShadowRight,
                    kPageShadowTop + kPageShadowBottom);
  pp::Size old_document_size = document_size_;
  document_size_ = pp::Size(page_size.width(), 0);
  for (int i = 0; i < num_pages; ++i) {
    if (i != 0) {
      // Add space for horizontal separator.
      document_size_.Enlarge(0, kPageSeparatorThickness);
    }

    pp::Rect rect(pp::Point(0, document_size_.height()), page_size);
    page_rects.push_back(rect);

    document_size_.Enlarge(0, page_size.height());
  }

  // Create blank pages.
  for (int i = 1; i < num_pages; ++i) {
    pp::Rect page_rect(page_rects[i]);
    page_rect.Inset(kPageShadowLeft, kPageShadowTop,
                    kPageShadowRight, kPageShadowBottom);
    double width_in_points =
        page_rect.width() * kPointsPerInch / kPixelsPerInch;
    double height_in_points =
        page_rect.height() * kPointsPerInch / kPixelsPerInch;
    FPDFPage_New(doc_, i, width_in_points, height_in_points);
    pages_.push_back(new PDFiumPage(this, i, page_rect, true));
    // TODO(thestig) Remove after debugging http://crbug.com/402035
    CHECK(pages_.back());
  }

  CalculateVisiblePages();
  if (document_size_ != old_document_size)
    client_->DocumentSizeUpdated(document_size_);
}

void PDFiumEngine::LoadDocument() {
  // Check if the document is ready for loading. If it isn't just bail for now,
  // we will call LoadDocument() again later.
  if (!doc_ && !doc_loader_.IsDocumentComplete() &&
      !FPDFAvail_IsDocAvail(fpdf_availability_, &download_hints_)) {
    return;
  }

  // If we're in the middle of getting a password, just return. We will retry
  // loading the document after we get the password anyway.
  if (getting_password_)
    return;

  ScopedUnsupportedFeature scoped_unsupported_feature(this);
  bool needs_password = false;
  if (TryLoadingDoc(false, std::string(), &needs_password)) {
    ContinueLoadingDocument(false, std::string());
    return;
  }
  if (needs_password)
    GetPasswordAndLoad();
  else
    client_->DocumentLoadFailed();
}

bool PDFiumEngine::TryLoadingDoc(bool with_password,
                                 const std::string& password,
                                 bool* needs_password) {
  *needs_password = false;
  if (doc_)
    return true;

  const char* password_cstr = NULL;
  if (with_password) {
    password_cstr = password.c_str();
    password_tries_remaining_--;
  }
  if (doc_loader_.IsDocumentComplete())
    doc_ = FPDF_LoadCustomDocument(&file_access_, password_cstr);
  else
    doc_ = FPDFAvail_GetDocument(fpdf_availability_, password_cstr);

  if (!doc_ && FPDF_GetLastError() == FPDF_ERR_PASSWORD)
    *needs_password = true;

  return doc_ != NULL;
}

void PDFiumEngine::GetPasswordAndLoad() {
  getting_password_ = true;
  DCHECK(!doc_ && FPDF_GetLastError() == FPDF_ERR_PASSWORD);
  client_->GetDocumentPassword(password_factory_.NewCallbackWithOutput(
      &PDFiumEngine::OnGetPasswordComplete));
}

void PDFiumEngine::OnGetPasswordComplete(int32_t result,
                                         const pp::Var& password) {
  getting_password_ = false;

  bool password_given = false;
  std::string password_text;
  if (result == PP_OK && password.is_string()) {
    password_text = password.AsString();
    if (!password_text.empty())
      password_given = true;
  }
  ContinueLoadingDocument(password_given, password_text);
}

void PDFiumEngine::ContinueLoadingDocument(
    bool has_password,
    const std::string& password) {
  ScopedUnsupportedFeature scoped_unsupported_feature(this);

  bool needs_password = false;
  bool loaded = TryLoadingDoc(has_password, password, &needs_password);
  bool password_incorrect = !loaded && has_password && needs_password;
  if (password_incorrect && password_tries_remaining_ > 0) {
    GetPasswordAndLoad();
    return;
  }

  if (!doc_) {
    client_->DocumentLoadFailed();
    return;
  }

  if (FPDFDoc_GetPageMode(doc_) == PAGEMODE_USEOUTLINES)
    client_->DocumentHasUnsupportedFeature("Bookmarks");

  permissions_ = FPDF_GetDocPermissions(doc_);

  if (!form_) {
    // Only returns 0 when data isn't available.  If form data is downloaded, or
    // if this isn't a form, returns positive values.
    if (!doc_loader_.IsDocumentComplete() &&
        !FPDFAvail_IsFormAvail(fpdf_availability_, &download_hints_)) {
      return;
    }

    form_ = FPDFDOC_InitFormFillEnviroument(
        doc_, static_cast<FPDF_FORMFILLINFO*>(this));
    FPDF_SetFormFieldHighlightColor(form_, 0, kFormHighlightColor);
    FPDF_SetFormFieldHighlightAlpha(form_, kFormHighlightAlpha);
  }

  if (!doc_loader_.IsDocumentComplete()) {
    // Check if the first page is available.  In a linearized PDF, that is not
    // always page 0.  Doing this gives us the default page size, since when the
    // document is available, the first page is available as well.
    CheckPageAvailable(FPDFAvail_GetFirstPageNum(doc_), &pending_pages_);
  }

  LoadPageInfo(false);

  if (doc_loader_.IsDocumentComplete())
    FinishLoadingDocument();
}

void PDFiumEngine::LoadPageInfo(bool reload) {
  pending_pages_.clear();
  pp::Size old_document_size = document_size_;
  document_size_ = pp::Size();
  std::vector<pp::Rect> page_rects;
  int page_count = FPDF_GetPageCount(doc_);
  bool doc_complete = doc_loader_.IsDocumentComplete();
  for (int i = 0; i < page_count; ++i) {
    if (i != 0) {
      // Add space for horizontal separator.
      document_size_.Enlarge(0, kPageSeparatorThickness);
    }

    // Get page availability. If reload==false, and document is not loaded yet
    // (we are using async loading) - mark all pages as unavailable.
    // If reload==true (we have document constructed already), get page
    // availability flag from already existing PDFiumPage class.
    bool page_available = reload ? pages_[i]->available() : doc_complete;

    pp::Size size = page_available ? GetPageSize(i) : default_page_size_;
    size.Enlarge(kPageShadowLeft + kPageShadowRight,
                 kPageShadowTop + kPageShadowBottom);
    pp::Rect rect(pp::Point(0, document_size_.height()), size);
    page_rects.push_back(rect);

    if (size.width() > document_size_.width())
      document_size_.set_width(size.width());

    document_size_.Enlarge(0, size.height());
  }

  for (int i = 0; i < page_count; ++i) {
    // Center pages relative to the entire document.
    page_rects[i].set_x((document_size_.width() - page_rects[i].width()) / 2);
    pp::Rect page_rect(page_rects[i]);
    page_rect.Inset(kPageShadowLeft, kPageShadowTop,
                    kPageShadowRight, kPageShadowBottom);
    if (reload) {
      pages_[i]->set_rect(page_rect);
    } else {
      pages_.push_back(new PDFiumPage(this, i, page_rect, doc_complete));
      // TODO(thestig) Remove after debugging http://crbug.com/402035
      CHECK(pages_.back());
    }
  }

  CalculateVisiblePages();
  if (document_size_ != old_document_size)
    client_->DocumentSizeUpdated(document_size_);
}

void PDFiumEngine::CalculateVisiblePages() {
  // Clear pending requests queue, since it may contain requests to the pages
  // that are already invisible (after scrolling for example).
  pending_pages_.clear();
  doc_loader_.ClearPendingRequests();

  visible_pages_.clear();
  pp::Rect visible_rect(plugin_size_);
  for (size_t i = 0; i < pages_.size(); ++i) {
    // Check an entire PageScreenRect, since we might need to repaint side
    // borders and shadows even if the page itself is not visible.
    // For example, when user use pdf with different page sizes and zoomed in
    // outside page area.
    if (visible_rect.Intersects(GetPageScreenRect(i))) {
      visible_pages_.push_back(i);
      CheckPageAvailable(i, &pending_pages_);
    } else {
      // Need to unload pages when we're not using them, since some PDFs use a
      // lot of memory.  See http://crbug.com/48791
      if (defer_page_unload_) {
        deferred_page_unloads_.push_back(i);
      } else {
        pages_[i]->Unload();
      }

      // If the last mouse down was on a page that's no longer visible, reset
      // that variable so that we don't send keyboard events to it (the focus
      // will be lost when the page is first closed anyways).
      if (static_cast<int>(i) == last_page_mouse_down_)
        last_page_mouse_down_ = -1;
    }
  }

  // Any pending highlighting of form fields will be invalid since these are in
  // screen coordinates.
  form_highlights_.clear();

  if (visible_pages_.size() == 0)
    first_visible_page_ = -1;
  else
    first_visible_page_ = visible_pages_.front();

  int most_visible_page = first_visible_page_;
  // Check if the next page is more visible than the first one.
  if (most_visible_page != -1 &&
      pages_.size() > 0 &&
      most_visible_page < static_cast<int>(pages_.size()) - 1) {
    pp::Rect rc_first =
        visible_rect.Intersect(GetPageScreenRect(most_visible_page));
    pp::Rect rc_next =
        visible_rect.Intersect(GetPageScreenRect(most_visible_page + 1));
    if (rc_next.height() > rc_first.height())
      most_visible_page++;
  }

  SetCurrentPage(most_visible_page);
}

bool PDFiumEngine::IsPageVisible(int index) const {
  for (size_t i = 0; i < visible_pages_.size(); ++i) {
    if (visible_pages_[i] == index)
      return true;
  }

  return false;
}

bool PDFiumEngine::CheckPageAvailable(int index, std::vector<int>* pending) {
  if (!doc_ || !form_)
    return false;

  if (static_cast<int>(pages_.size()) > index && pages_[index]->available())
    return true;

  if (!FPDFAvail_IsPageAvail(fpdf_availability_, index, &download_hints_)) {
    size_t j;
    for (j = 0; j < pending->size(); ++j) {
      if ((*pending)[j] == index)
        break;
    }

    if (j == pending->size())
      pending->push_back(index);
    return false;
  }

  if (static_cast<int>(pages_.size()) > index)
    pages_[index]->set_available(true);
  if (!default_page_size_.GetArea())
    default_page_size_ = GetPageSize(index);
  return true;
}

pp::Size PDFiumEngine::GetPageSize(int index) {
  pp::Size size;
  double width_in_points = 0;
  double height_in_points = 0;
  int rv = FPDF_GetPageSizeByIndex(
      doc_, index, &width_in_points, &height_in_points);

  if (rv) {
    int width_in_pixels = static_cast<int>(
        width_in_points * kPixelsPerInch / kPointsPerInch);
    int height_in_pixels = static_cast<int>(
        height_in_points * kPixelsPerInch / kPointsPerInch);
    if (current_rotation_ % 2 == 1)
      std::swap(width_in_pixels, height_in_pixels);
    size = pp::Size(width_in_pixels, height_in_pixels);
  }
  return size;
}

int PDFiumEngine::StartPaint(int page_index, const pp::Rect& dirty) {
  // For the first time we hit paint, do nothing and just record the paint for
  // the next callback.  This keeps the UI responsive in case the user is doing
  // a lot of scrolling.
  ProgressivePaint progressive;
  progressive.rect = dirty;
  progressive.page_index = page_index;
  progressive.bitmap = NULL;
  progressive.painted_ = false;
  progressive_paints_.push_back(progressive);
  return progressive_paints_.size() - 1;
}

bool PDFiumEngine::ContinuePaint(int progressive_index,
                                 pp::ImageData* image_data) {
#if defined(OS_LINUX)
  g_last_instance_id = client_->GetPluginInstance()->pp_instance();
#endif

  int rv;
  int page_index = progressive_paints_[progressive_index].page_index;
  last_progressive_start_time_ = base::Time::Now();
  if (progressive_paints_[progressive_index].bitmap) {
    rv = FPDF_RenderPage_Continue(
        pages_[page_index]->GetPage(), static_cast<IFSDK_PAUSE*>(this));
  } else {
    pp::Rect dirty = progressive_paints_[progressive_index].rect;
    progressive_paints_[progressive_index].bitmap = CreateBitmap(dirty,
                                                                 image_data);
    int start_x, start_y, size_x, size_y;
    GetPDFiumRect(
        page_index, dirty, &start_x, &start_y, &size_x, &size_y);
    FPDFBitmap_FillRect(progressive_paints_[progressive_index].bitmap, start_x,
                        start_y, size_x, size_y, 0xFFFFFFFF);
    rv = FPDF_RenderPageBitmap_Start(
        progressive_paints_[progressive_index].bitmap,
        pages_[page_index]->GetPage(), start_x, start_y, size_x, size_y,
        current_rotation_,
        GetRenderingFlags(), static_cast<IFSDK_PAUSE*>(this));
  }
  return rv != FPDF_RENDER_TOBECOUNTINUED;
}

void PDFiumEngine::FinishPaint(int progressive_index,
                               pp::ImageData* image_data) {
  int page_index = progressive_paints_[progressive_index].page_index;
  pp::Rect dirty_in_screen = progressive_paints_[progressive_index].rect;
  FPDF_BITMAP bitmap = progressive_paints_[progressive_index].bitmap;
  int start_x, start_y, size_x, size_y;
  GetPDFiumRect(
      page_index, dirty_in_screen, &start_x, &start_y, &size_x, &size_y);

  // Draw the forms.
  FPDF_FFLDraw(
      form_, bitmap, pages_[page_index]->GetPage(), start_x, start_y, size_x,
      size_y, current_rotation_, GetRenderingFlags());

  FillPageSides(progressive_index);

  // Paint the page shadows.
  PaintPageShadow(progressive_index, image_data);

  DrawSelections(progressive_index, image_data);

  FPDF_RenderPage_Close(pages_[page_index]->GetPage());
  FPDFBitmap_Destroy(bitmap);
  progressive_paints_.erase(progressive_paints_.begin() + progressive_index);

  client_->DocumentPaintOccurred();
}

void PDFiumEngine::CancelPaints() {
  for (size_t i = 0; i < progressive_paints_.size(); ++i) {
    FPDF_RenderPage_Close(pages_[progressive_paints_[i].page_index]->GetPage());
    FPDFBitmap_Destroy(progressive_paints_[i].bitmap);
  }
  progressive_paints_.clear();
}

void PDFiumEngine::FillPageSides(int progressive_index) {
  int page_index = progressive_paints_[progressive_index].page_index;
  pp::Rect dirty_in_screen = progressive_paints_[progressive_index].rect;
  FPDF_BITMAP bitmap = progressive_paints_[progressive_index].bitmap;

  pp::Rect page_rect = pages_[page_index]->rect();
  if (page_rect.x() > 0) {
    pp::Rect left(0,
                  page_rect.y() - kPageShadowTop,
                  page_rect.x() - kPageShadowLeft,
                  page_rect.height() + kPageShadowTop +
                      kPageShadowBottom + kPageSeparatorThickness);
    left = GetScreenRect(left).Intersect(dirty_in_screen);

    FPDFBitmap_FillRect(bitmap, left.x() - dirty_in_screen.x(),
                        left.y() - dirty_in_screen.y(), left.width(),
                        left.height(), kBackgroundColor);
  }

  if (page_rect.right() < document_size_.width()) {
    pp::Rect right(page_rect.right() + kPageShadowRight,
                   page_rect.y() - kPageShadowTop,
                   document_size_.width() - page_rect.right() -
                      kPageShadowRight,
                   page_rect.height() + kPageShadowTop +
                       kPageShadowBottom + kPageSeparatorThickness);
    right = GetScreenRect(right).Intersect(dirty_in_screen);

    FPDFBitmap_FillRect(bitmap, right.x() - dirty_in_screen.x(),
                        right.y() - dirty_in_screen.y(), right.width(),
                        right.height(), kBackgroundColor);
  }

  // Paint separator.
  pp::Rect bottom(page_rect.x() - kPageShadowLeft,
                  page_rect.bottom() + kPageShadowBottom,
                  page_rect.width() + kPageShadowLeft + kPageShadowRight,
                  kPageSeparatorThickness);
  bottom = GetScreenRect(bottom).Intersect(dirty_in_screen);

  FPDFBitmap_FillRect(bitmap, bottom.x() - dirty_in_screen.x(),
                      bottom.y() - dirty_in_screen.y(), bottom.width(),
                      bottom.height(), kBackgroundColor);
}

void PDFiumEngine::PaintPageShadow(int progressive_index,
                                   pp::ImageData* image_data) {
  int page_index = progressive_paints_[progressive_index].page_index;
  pp::Rect dirty_in_screen = progressive_paints_[progressive_index].rect;
  pp::Rect page_rect = pages_[page_index]->rect();
  pp::Rect shadow_rect(page_rect);
  shadow_rect.Inset(-kPageShadowLeft, -kPageShadowTop,
                    -kPageShadowRight, -kPageShadowBottom);

  // Due to the rounding errors of the GetScreenRect it is possible to get
  // different size shadows on the left and right sides even they are defined
  // the same. To fix this issue let's calculate shadow rect and then shrink
  // it by the size of the shadows.
  shadow_rect = GetScreenRect(shadow_rect);
  page_rect = shadow_rect;

  page_rect.Inset(static_cast<int>(ceil(kPageShadowLeft * current_zoom_)),
                  static_cast<int>(ceil(kPageShadowTop * current_zoom_)),
                  static_cast<int>(ceil(kPageShadowRight * current_zoom_)),
                  static_cast<int>(ceil(kPageShadowBottom * current_zoom_)));

  DrawPageShadow(page_rect, shadow_rect, dirty_in_screen, image_data);
}

void PDFiumEngine::DrawSelections(int progressive_index,
                                  pp::ImageData* image_data) {
  int page_index = progressive_paints_[progressive_index].page_index;
  pp::Rect dirty_in_screen = progressive_paints_[progressive_index].rect;

  void* region = NULL;
  int stride;
  GetRegion(dirty_in_screen.point(), image_data, &region, &stride);

  std::vector<pp::Rect> highlighted_rects;
  pp::Rect visible_rect = GetVisibleRect();
  for (size_t k = 0; k < selection_.size(); ++k) {
    if (selection_[k].page_index() != page_index)
      continue;
    std::vector<pp::Rect> rects = selection_[k].GetScreenRects(
        visible_rect.point(), current_zoom_, current_rotation_);
    for (size_t j = 0; j < rects.size(); ++j) {
      pp::Rect visible_selection = rects[j].Intersect(dirty_in_screen);
      if (visible_selection.IsEmpty())
        continue;

      visible_selection.Offset(
          -dirty_in_screen.point().x(), -dirty_in_screen.point().y());
      Highlight(region, stride, visible_selection, &highlighted_rects);
    }
  }

  for (size_t k = 0; k < form_highlights_.size(); ++k) {
    pp::Rect visible_selection = form_highlights_[k].Intersect(dirty_in_screen);
      if (visible_selection.IsEmpty())
        continue;

    visible_selection.Offset(
        -dirty_in_screen.point().x(), -dirty_in_screen.point().y());
    Highlight(region, stride, visible_selection, &highlighted_rects);
  }
  form_highlights_.clear();
}

void PDFiumEngine::PaintUnavailablePage(int page_index,
                                        const pp::Rect& dirty,
                                        pp::ImageData* image_data) {
  int start_x, start_y, size_x, size_y;
  GetPDFiumRect(page_index, dirty, &start_x, &start_y, &size_x, &size_y);
  FPDF_BITMAP bitmap = CreateBitmap(dirty, image_data);
  FPDFBitmap_FillRect(bitmap, start_x, start_y, size_x, size_y,
                      kPendingPageColor);

  pp::Rect loading_text_in_screen(
      pages_[page_index]->rect().width() / 2,
      pages_[page_index]->rect().y() + kLoadingTextVerticalOffset, 0, 0);
  loading_text_in_screen = GetScreenRect(loading_text_in_screen);
  FPDFBitmap_Destroy(bitmap);
}

int PDFiumEngine::GetProgressiveIndex(int page_index) const {
  for (size_t i = 0; i < progressive_paints_.size(); ++i) {
    if (progressive_paints_[i].page_index == page_index)
      return i;
  }
  return -1;
}

FPDF_BITMAP PDFiumEngine::CreateBitmap(const pp::Rect& rect,
                                       pp::ImageData* image_data) const {
  void* region;
  int stride;
  GetRegion(rect.point(), image_data, &region, &stride);
  if (!region)
    return NULL;
  return FPDFBitmap_CreateEx(
      rect.width(), rect.height(), FPDFBitmap_BGRx, region, stride);
}

void PDFiumEngine::GetPDFiumRect(
    int page_index, const pp::Rect& rect, int* start_x, int* start_y,
    int* size_x, int* size_y) const {
  pp::Rect page_rect = GetScreenRect(pages_[page_index]->rect());
  page_rect.Offset(-rect.x(), -rect.y());

  *start_x = page_rect.x();
  *start_y = page_rect.y();
  *size_x = page_rect.width();
  *size_y = page_rect.height();
}

int PDFiumEngine::GetRenderingFlags() const {
  int flags = FPDF_LCD_TEXT | FPDF_NO_CATCH;
  if (render_grayscale_)
    flags |= FPDF_GRAYSCALE;
  if (client_->IsPrintPreview())
    flags |= FPDF_PRINTING;
  return flags;
}

pp::Rect PDFiumEngine::GetVisibleRect() const {
  pp::Rect rv;
  rv.set_x(static_cast<int>(position_.x() / current_zoom_));
  rv.set_y(static_cast<int>(position_.y() / current_zoom_));
  rv.set_width(static_cast<int>(ceil(plugin_size_.width() / current_zoom_)));
  rv.set_height(static_cast<int>(ceil(plugin_size_.height() / current_zoom_)));
  return rv;
}

pp::Rect PDFiumEngine::GetPageScreenRect(int page_index) const {
  // Since we use this rect for creating the PDFium bitmap, also include other
  // areas around the page that we might need to update such as the page
  // separator and the sides if the page is narrower than the document.
  return GetScreenRect(pp::Rect(
      0,
      pages_[page_index]->rect().y() - kPageShadowTop,
      document_size_.width(),
      pages_[page_index]->rect().height() + kPageShadowTop +
          kPageShadowBottom + kPageSeparatorThickness));
}

pp::Rect PDFiumEngine::GetScreenRect(const pp::Rect& rect) const {
  pp::Rect rv;
  int right =
      static_cast<int>(ceil(rect.right() * current_zoom_ - position_.x()));
  int bottom =
    static_cast<int>(ceil(rect.bottom() * current_zoom_ - position_.y()));

  rv.set_x(static_cast<int>(rect.x() * current_zoom_ - position_.x()));
  rv.set_y(static_cast<int>(rect.y() * current_zoom_ - position_.y()));
  rv.set_width(right - rv.x());
  rv.set_height(bottom - rv.y());
  return rv;
}

void PDFiumEngine::Highlight(void* buffer,
                             int stride,
                             const pp::Rect& rect,
                             std::vector<pp::Rect>* highlighted_rects) {
  if (!buffer)
    return;

  pp::Rect new_rect = rect;
  for (size_t i = 0; i < highlighted_rects->size(); ++i)
    new_rect = new_rect.Subtract((*highlighted_rects)[i]);

  highlighted_rects->push_back(new_rect);
  int l = new_rect.x();
  int t = new_rect.y();
  int w = new_rect.width();
  int h = new_rect.height();

  for (int y = t; y < t + h; ++y) {
    for (int x = l; x < l + w; ++x) {
      uint8* pixel = static_cast<uint8*>(buffer) + y * stride + x * 4;
      //  This is our highlight color.
      pixel[0] = static_cast<uint8>(
          pixel[0] * (kHighlightColorB / 255.0));
      pixel[1] = static_cast<uint8>(
          pixel[1] * (kHighlightColorG / 255.0));
      pixel[2] = static_cast<uint8>(
          pixel[2] * (kHighlightColorR / 255.0));
    }
  }
}

PDFiumEngine::SelectionChangeInvalidator::SelectionChangeInvalidator(
    PDFiumEngine* engine) : engine_(engine) {
  previous_origin_ = engine_->GetVisibleRect().point();
  GetVisibleSelectionsScreenRects(&old_selections_);
}

PDFiumEngine::SelectionChangeInvalidator::~SelectionChangeInvalidator() {
  // Offset the old selections if the document scrolled since we recorded them.
  pp::Point offset = previous_origin_ - engine_->GetVisibleRect().point();
  for (size_t i = 0; i < old_selections_.size(); ++i)
    old_selections_[i].Offset(offset);

  std::vector<pp::Rect> new_selections;
  GetVisibleSelectionsScreenRects(&new_selections);
  for (size_t i = 0; i < new_selections.size(); ++i) {
    for (size_t j = 0; j < old_selections_.size(); ++j) {
      if (new_selections[i] == old_selections_[j]) {
        // Rectangle was selected before and after, so no need to invalidate it.
        // Mark the rectangles by setting them to empty.
        new_selections[i] = old_selections_[j] = pp::Rect();
      }
    }
  }

  for (size_t i = 0; i < old_selections_.size(); ++i) {
    if (!old_selections_[i].IsEmpty())
      engine_->client_->Invalidate(old_selections_[i]);
  }
  for (size_t i = 0; i < new_selections.size(); ++i) {
    if (!new_selections[i].IsEmpty())
      engine_->client_->Invalidate(new_selections[i]);
  }
  engine_->OnSelectionChanged();
}

void
PDFiumEngine::SelectionChangeInvalidator::GetVisibleSelectionsScreenRects(
    std::vector<pp::Rect>* rects) {
  pp::Rect visible_rect = engine_->GetVisibleRect();
  for (size_t i = 0; i < engine_->selection_.size(); ++i) {
    int page_index = engine_->selection_[i].page_index();
    if (!engine_->IsPageVisible(page_index))
      continue;  // This selection is on a page that's not currently visible.

    std::vector<pp::Rect> selection_rects =
        engine_->selection_[i].GetScreenRects(
            visible_rect.point(),
            engine_->current_zoom_,
            engine_->current_rotation_);
    rects->insert(rects->end(), selection_rects.begin(), selection_rects.end());
  }
}

void PDFiumEngine::DeviceToPage(int page_index,
                                float device_x,
                                float device_y,
                                double* page_x,
                                double* page_y) {
  *page_x = *page_y = 0;
  int temp_x = static_cast<int>((device_x + position_.x())/ current_zoom_ -
      pages_[page_index]->rect().x());
  int temp_y = static_cast<int>((device_y + position_.y())/ current_zoom_ -
      pages_[page_index]->rect().y());
  FPDF_DeviceToPage(
      pages_[page_index]->GetPage(), 0, 0,
      pages_[page_index]->rect().width(),  pages_[page_index]->rect().height(),
      current_rotation_, temp_x, temp_y, page_x, page_y);
}

int PDFiumEngine::GetVisiblePageIndex(FPDF_PAGE page) {
  for (size_t i = 0; i < visible_pages_.size(); ++i) {
    if (pages_[visible_pages_[i]]->GetPage() == page)
      return visible_pages_[i];
  }
  return -1;
}

void PDFiumEngine::SetCurrentPage(int index) {
  if (index == most_visible_page_ || !form_)
    return;
  if (most_visible_page_ != -1 && called_do_document_action_) {
    FPDF_PAGE old_page = pages_[most_visible_page_]->GetPage();
    FORM_DoPageAAction(old_page, form_, FPDFPAGE_AACTION_CLOSE);
  }
  most_visible_page_ = index;
#if defined(OS_LINUX)
    g_last_instance_id = client_->GetPluginInstance()->pp_instance();
#endif
  if (most_visible_page_ != -1 && called_do_document_action_) {
    FPDF_PAGE new_page = pages_[most_visible_page_]->GetPage();
    FORM_DoPageAAction(new_page, form_, FPDFPAGE_AACTION_OPEN);
  }
}

void PDFiumEngine::TransformPDFPageForPrinting(
    FPDF_PAGE page,
    const PP_PrintSettings_Dev& print_settings) {
  // Get the source page width and height in points.
  const double src_page_width = FPDF_GetPageWidth(page);
  const double src_page_height = FPDF_GetPageHeight(page);

  const int src_page_rotation = FPDFPage_GetRotation(page);
  const bool fit_to_page = print_settings.print_scaling_option ==
      PP_PRINTSCALINGOPTION_FIT_TO_PRINTABLE_AREA;

  pp::Size page_size(print_settings.paper_size);
  pp::Rect content_rect(print_settings.printable_area);
  const bool rotated = (src_page_rotation % 2 == 1);
  SetPageSizeAndContentRect(rotated,
                            src_page_width > src_page_height,
                            &page_size,
                            &content_rect);

  // Compute the screen page width and height in points.
  const int actual_page_width =
      rotated ? page_size.height() : page_size.width();
  const int actual_page_height =
      rotated ? page_size.width() : page_size.height();

  const double scale_factor = CalculateScaleFactor(fit_to_page, content_rect,
                                                   src_page_width,
                                                   src_page_height, rotated);

  // Calculate positions for the clip box.
  ClipBox source_clip_box;
  CalculateClipBoxBoundary(page, scale_factor, rotated, &source_clip_box);

  // Calculate the translation offset values.
  double offset_x = 0;
  double offset_y = 0;
  if (fit_to_page) {
    CalculateScaledClipBoxOffset(content_rect, source_clip_box, &offset_x,
                                 &offset_y);
  } else {
    CalculateNonScaledClipBoxOffset(content_rect, src_page_rotation,
                                    actual_page_width, actual_page_height,
                                    source_clip_box, &offset_x, &offset_y);
  }

  // Reset the media box and crop box. When the page has crop box and media box,
  // the plugin will display the crop box contents and not the entire media box.
  // If the pages have different crop box values, the plugin will display a
  // document of multiple page sizes. To give better user experience, we
  // decided to have same crop box and media box values. Hence, the user will
  // see a list of uniform pages.
  FPDFPage_SetMediaBox(page, 0, 0, page_size.width(), page_size.height());
  FPDFPage_SetCropBox(page, 0, 0, page_size.width(), page_size.height());

  // Transformation is not required, return. Do this check only after updating
  // the media box and crop box. For more detailed information, please refer to
  // the comment block right before FPDF_SetMediaBox and FPDF_GetMediaBox calls.
  if (scale_factor == 1.0 && offset_x == 0 && offset_y == 0)
    return;


  // All the positions have been calculated, now manipulate the PDF.
  FS_MATRIX matrix = {static_cast<float>(scale_factor),
                      0,
                      0,
                      static_cast<float>(scale_factor),
                      static_cast<float>(offset_x),
                      static_cast<float>(offset_y)};
  FS_RECTF cliprect = {static_cast<float>(source_clip_box.left+offset_x),
                       static_cast<float>(source_clip_box.top+offset_y),
                       static_cast<float>(source_clip_box.right+offset_x),
                       static_cast<float>(source_clip_box.bottom+offset_y)};
  FPDFPage_TransFormWithClip(page, &matrix, &cliprect);
  FPDFPage_TransformAnnots(page, scale_factor, 0, 0, scale_factor,
                           offset_x, offset_y);
}

void PDFiumEngine::DrawPageShadow(const pp::Rect& page_rc,
                                  const pp::Rect& shadow_rc,
                                  const pp::Rect& clip_rc,
                                  pp::ImageData* image_data) {
  pp::Rect page_rect(page_rc);
  page_rect.Offset(page_offset_);

  pp::Rect shadow_rect(shadow_rc);
  shadow_rect.Offset(page_offset_);

  pp::Rect clip_rect(clip_rc);
  clip_rect.Offset(page_offset_);

  // Page drop shadow parameters.
  const double factor = 0.5;
  uint32 depth = std::max(
      std::max(page_rect.x() - shadow_rect.x(),
               page_rect.y() - shadow_rect.y()),
      std::max(shadow_rect.right() - page_rect.right(),
               shadow_rect.bottom() - page_rect.bottom()));
  depth = static_cast<uint32>(depth * 1.5) + 1;

  // We need to check depth only to verify our copy of shadow matrix is correct.
  if (!page_shadow_.get() || page_shadow_->depth() != depth)
    page_shadow_.reset(new ShadowMatrix(depth, factor, kBackgroundColor));

  DCHECK(!image_data->is_null());
  DrawShadow(image_data, shadow_rect, page_rect, clip_rect, *page_shadow_);
}

void PDFiumEngine::GetRegion(const pp::Point& location,
                             pp::ImageData* image_data,
                             void** region,
                             int* stride) const {
  if (image_data->is_null()) {
    DCHECK(plugin_size_.IsEmpty());
    *stride = 0;
    *region = NULL;
    return;
  }
  char* buffer = static_cast<char*>(image_data->data());
  *stride = image_data->stride();

  pp::Point offset_location = location + page_offset_;
  // TODO: update this when we support BIDI and scrollbars can be on the left.
  if (!buffer ||
      !pp::Rect(page_offset_, plugin_size_).Contains(offset_location)) {
    *region = NULL;
    return;
  }

  buffer += location.y() * (*stride);
  buffer += (location.x() + page_offset_.x()) * 4;
  *region = buffer;
}

void PDFiumEngine::OnSelectionChanged() {
  if (HasPermission(PDFEngine::PERMISSION_COPY))
    pp::PDF::SetSelectedText(GetPluginInstance(), GetSelectedText().c_str());
}

void PDFiumEngine::Form_Invalidate(FPDF_FORMFILLINFO* param,
                                   FPDF_PAGE page,
                                   double left,
                                   double top,
                                   double right,
                                   double bottom) {
  PDFiumEngine* engine = static_cast<PDFiumEngine*>(param);
  int page_index = engine->GetVisiblePageIndex(page);
  if (page_index == -1) {
    // This can sometime happen when the page is closed because it went off
    // screen, and PDFium invalidates the control as it's being deleted.
    return;
  }

  pp::Rect rect = engine->pages_[page_index]->PageToScreen(
      engine->GetVisibleRect().point(), engine->current_zoom_, left, top, right,
      bottom, engine->current_rotation_);
  engine->client_->Invalidate(rect);
}

void PDFiumEngine::Form_OutputSelectedRect(FPDF_FORMFILLINFO* param,
                                           FPDF_PAGE page,
                                           double left,
                                           double top,
                                           double right,
                                           double bottom) {
  PDFiumEngine* engine = static_cast<PDFiumEngine*>(param);
  int page_index = engine->GetVisiblePageIndex(page);
  if (page_index == -1) {
    NOTREACHED();
    return;
  }
  pp::Rect rect = engine->pages_[page_index]->PageToScreen(
      engine->GetVisibleRect().point(), engine->current_zoom_, left, top, right,
      bottom, engine->current_rotation_);
  engine->form_highlights_.push_back(rect);
}

void PDFiumEngine::Form_SetCursor(FPDF_FORMFILLINFO* param, int cursor_type) {
  // We don't need this since it's not enough to change the cursor in all
  // scenarios.  Instead, we check which form field we're under in OnMouseMove.
}

int PDFiumEngine::Form_SetTimer(FPDF_FORMFILLINFO* param,
                                int elapse,
                                TimerCallback timer_func) {
  PDFiumEngine* engine = static_cast<PDFiumEngine*>(param);
  engine->timers_[++engine->next_timer_id_] =
      std::pair<int, TimerCallback>(elapse, timer_func);
  engine->client_->ScheduleCallback(engine->next_timer_id_, elapse);
  return engine->next_timer_id_;
}

void PDFiumEngine::Form_KillTimer(FPDF_FORMFILLINFO* param, int timer_id) {
  PDFiumEngine* engine = static_cast<PDFiumEngine*>(param);
  engine->timers_.erase(timer_id);
}

FPDF_SYSTEMTIME PDFiumEngine::Form_GetLocalTime(FPDF_FORMFILLINFO* param) {
  base::Time time = base::Time::Now();
  base::Time::Exploded exploded;
  time.LocalExplode(&exploded);

  FPDF_SYSTEMTIME rv;
  rv.wYear = exploded.year;
  rv.wMonth = exploded.month;
  rv.wDayOfWeek = exploded.day_of_week;
  rv.wDay = exploded.day_of_month;
  rv.wHour = exploded.hour;
  rv.wMinute = exploded.minute;
  rv.wSecond = exploded.second;
  rv.wMilliseconds = exploded.millisecond;
  return rv;
}

void PDFiumEngine::Form_OnChange(FPDF_FORMFILLINFO* param) {
  // Don't care about.
}

FPDF_PAGE PDFiumEngine::Form_GetPage(FPDF_FORMFILLINFO* param,
                                     FPDF_DOCUMENT document,
                                     int page_index) {
  PDFiumEngine* engine = static_cast<PDFiumEngine*>(param);
  if (page_index < 0 || page_index >= static_cast<int>(engine->pages_.size()))
    return NULL;
  return engine->pages_[page_index]->GetPage();
}

FPDF_PAGE PDFiumEngine::Form_GetCurrentPage(FPDF_FORMFILLINFO* param,
                                            FPDF_DOCUMENT document) {
  // TODO(jam): find out what this is used for.
  PDFiumEngine* engine = static_cast<PDFiumEngine*>(param);
  int index = engine->last_page_mouse_down_;
  if (index == -1) {
    index = engine->GetMostVisiblePage();
    if (index == -1) {
      NOTREACHED();
      return NULL;
    }
  }

  return engine->pages_[index]->GetPage();
}

int PDFiumEngine::Form_GetRotation(FPDF_FORMFILLINFO* param, FPDF_PAGE page) {
  return 0;
}

void PDFiumEngine::Form_ExecuteNamedAction(FPDF_FORMFILLINFO* param,
                                           FPDF_BYTESTRING named_action) {
  PDFiumEngine* engine = static_cast<PDFiumEngine*>(param);
  std::string action(named_action);
  if (action == "Print") {
    engine->client_->Print();
    return;
  }

  int index = engine->last_page_mouse_down_;
  /* Don't try to calculate the most visible page if we don't have a left click
     before this event (this code originally copied Form_GetCurrentPage which of
     course needs to do that and which doesn't have recursion). This can end up
     causing infinite recursion. See http://crbug.com/240413 for more
     information. Either way, it's not necessary for the spec'd list of named
     actions.
  if (index == -1)
    index = engine->GetMostVisiblePage();
  */
  if (index == -1)
    return;

  // This is the only list of named actions per the spec (see 12.6.4.11). Adobe
  // Reader supports more, like FitWidth, but since they're not part of the spec
  // and we haven't got bugs about them, no need to now.
  if (action == "NextPage") {
    engine->client_->ScrollToPage(index + 1);
  } else if (action == "PrevPage") {
    engine->client_->ScrollToPage(index - 1);
  } else if (action == "FirstPage") {
    engine->client_->ScrollToPage(0);
  } else if (action == "LastPage") {
    engine->client_->ScrollToPage(engine->pages_.size() - 1);
  }
}

void PDFiumEngine::Form_SetTextFieldFocus(FPDF_FORMFILLINFO* param,
                                          FPDF_WIDESTRING value,
                                          FPDF_DWORD valueLen,
                                          FPDF_BOOL is_focus) {
  // Do nothing for now.
  // TODO(gene): use this signal to trigger OSK.
}

void PDFiumEngine::Form_DoURIAction(FPDF_FORMFILLINFO* param,
                                    FPDF_BYTESTRING uri) {
  PDFiumEngine* engine = static_cast<PDFiumEngine*>(param);
  engine->client_->NavigateTo(std::string(uri), false);
}

void PDFiumEngine::Form_DoGoToAction(FPDF_FORMFILLINFO* param,
                                     int page_index,
                                     int zoom_mode,
                                     float* position_array,
                                     int size_of_array) {
  PDFiumEngine* engine = static_cast<PDFiumEngine*>(param);
  engine->client_->ScrollToPage(page_index);
}

int PDFiumEngine::Form_Alert(IPDF_JSPLATFORM* param,
                             FPDF_WIDESTRING message,
                             FPDF_WIDESTRING title,
                             int type,
                             int icon) {
  // See fpdfformfill.h for these values.
  enum AlertType {
    ALERT_TYPE_OK = 0,
    ALERT_TYPE_OK_CANCEL,
    ALERT_TYPE_YES_ON,
    ALERT_TYPE_YES_NO_CANCEL
  };

  enum AlertResult {
    ALERT_RESULT_OK = 1,
    ALERT_RESULT_CANCEL,
    ALERT_RESULT_NO,
    ALERT_RESULT_YES
  };

  PDFiumEngine* engine = static_cast<PDFiumEngine*>(param);
  std::string message_str =
      base::UTF16ToUTF8(reinterpret_cast<const base::char16*>(message));
  if (type == ALERT_TYPE_OK) {
    engine->client_->Alert(message_str);
    return ALERT_RESULT_OK;
  }

  bool rv = engine->client_->Confirm(message_str);
  if (type == ALERT_TYPE_OK_CANCEL)
    return rv ? ALERT_RESULT_OK : ALERT_RESULT_CANCEL;
  return rv ? ALERT_RESULT_YES : ALERT_RESULT_NO;
}

void PDFiumEngine::Form_Beep(IPDF_JSPLATFORM* param, int type) {
  // Beeps are annoying, and not possible using javascript, so ignore for now.
}

int PDFiumEngine::Form_Response(IPDF_JSPLATFORM* param,
                                FPDF_WIDESTRING question,
                                FPDF_WIDESTRING title,
                                FPDF_WIDESTRING default_response,
                                FPDF_WIDESTRING label,
                                FPDF_BOOL password,
                                void* response,
                                int length) {
  std::string question_str = base::UTF16ToUTF8(
      reinterpret_cast<const base::char16*>(question));
  std::string default_str = base::UTF16ToUTF8(
      reinterpret_cast<const base::char16*>(default_response));

  PDFiumEngine* engine = static_cast<PDFiumEngine*>(param);
  std::string rv = engine->client_->Prompt(question_str, default_str);
  base::string16 rv_16 = base::UTF8ToUTF16(rv);
  int rv_bytes = rv_16.size() * sizeof(base::char16);
  if (response) {
    int bytes_to_copy = rv_bytes < length ? rv_bytes : length;
    memcpy(response, rv_16.c_str(), bytes_to_copy);
  }
  return rv_bytes;
}

int PDFiumEngine::Form_GetFilePath(IPDF_JSPLATFORM* param,
                                   void* file_path,
                                   int length) {
  PDFiumEngine* engine = static_cast<PDFiumEngine*>(param);
  std::string rv = engine->client_->GetURL();
  if (file_path && rv.size() <= static_cast<size_t>(length))
    memcpy(file_path, rv.c_str(), rv.size());
  return rv.size();
}

void PDFiumEngine::Form_Mail(IPDF_JSPLATFORM* param,
                             void* mail_data,
                             int length,
                             FPDF_BOOL ui,
                             FPDF_WIDESTRING to,
                             FPDF_WIDESTRING subject,
                             FPDF_WIDESTRING cc,
                             FPDF_WIDESTRING bcc,
                             FPDF_WIDESTRING message) {
  DCHECK(length == 0);  // Don't handle attachments; no way with mailto.
  std::string to_str =
      base::UTF16ToUTF8(reinterpret_cast<const base::char16*>(to));
  std::string cc_str =
      base::UTF16ToUTF8(reinterpret_cast<const base::char16*>(cc));
  std::string bcc_str =
      base::UTF16ToUTF8(reinterpret_cast<const base::char16*>(bcc));
  std::string subject_str =
      base::UTF16ToUTF8(reinterpret_cast<const base::char16*>(subject));
  std::string message_str =
      base::UTF16ToUTF8(reinterpret_cast<const base::char16*>(message));

  PDFiumEngine* engine = static_cast<PDFiumEngine*>(param);
  engine->client_->Email(to_str, cc_str, bcc_str, subject_str, message_str);
}

void PDFiumEngine::Form_Print(IPDF_JSPLATFORM* param,
                              FPDF_BOOL ui,
                              int start,
                              int end,
                              FPDF_BOOL silent,
                              FPDF_BOOL shrink_to_fit,
                              FPDF_BOOL print_as_image,
                              FPDF_BOOL reverse,
                              FPDF_BOOL annotations) {
  // No way to pass the extra information to the print dialog using JavaScript.
  // Just opening it is fine for now.
  PDFiumEngine* engine = static_cast<PDFiumEngine*>(param);
  engine->client_->Print();
}

void PDFiumEngine::Form_SubmitForm(IPDF_JSPLATFORM* param,
                                   void* form_data,
                                   int length,
                                   FPDF_WIDESTRING url) {
  std::string url_str =
      base::UTF16ToUTF8(reinterpret_cast<const base::char16*>(url));
  PDFiumEngine* engine = static_cast<PDFiumEngine*>(param);
  engine->client_->SubmitForm(url_str, form_data, length);
}

void PDFiumEngine::Form_GotoPage(IPDF_JSPLATFORM* param,
                                 int page_number) {
  PDFiumEngine* engine = static_cast<PDFiumEngine*>(param);
  engine->client_->ScrollToPage(page_number);
}

int PDFiumEngine::Form_Browse(IPDF_JSPLATFORM* param,
                              void* file_path,
                              int length) {
  PDFiumEngine* engine = static_cast<PDFiumEngine*>(param);
  std::string path = engine->client_->ShowFileSelectionDialog();
  if (path.size() + 1 <= static_cast<size_t>(length))
    memcpy(file_path, &path[0], path.size() + 1);
  return path.size() + 1;
}

FPDF_BOOL PDFiumEngine::Pause_NeedToPauseNow(IFSDK_PAUSE* param) {
  PDFiumEngine* engine = static_cast<PDFiumEngine*>(param);
  return (base::Time::Now() - engine->last_progressive_start_time_).
      InMilliseconds() > engine->progressive_paint_timeout_;
}

ScopedUnsupportedFeature::ScopedUnsupportedFeature(PDFiumEngine* engine)
    : engine_(engine), old_engine_(g_engine_for_unsupported) {
  g_engine_for_unsupported = engine_;
}

ScopedUnsupportedFeature::~ScopedUnsupportedFeature() {
  g_engine_for_unsupported = old_engine_;
}

PDFEngineExports* PDFEngineExports::Create() {
  return new PDFiumEngineExports;
}

namespace {

int CalculatePosition(FPDF_PAGE page,
                      const PDFiumEngineExports::RenderingSettings& settings,
                      pp::Rect* dest) {
  int page_width = static_cast<int>(
      FPDF_GetPageWidth(page) * settings.dpi_x / kPointsPerInch);
  int page_height = static_cast<int>(
      FPDF_GetPageHeight(page) * settings.dpi_y / kPointsPerInch);

  // Start by assuming that we will draw exactly to the bounds rect
  // specified.
  *dest = settings.bounds;

  int rotate = 0;  // normal orientation.

  // Auto-rotate landscape pages to print correctly.
  if (settings.autorotate &&
      (dest->width() > dest->height()) != (page_width > page_height)) {
    rotate = 3;  // 90 degrees counter-clockwise.
    std::swap(page_width, page_height);
  }

  // See if we need to scale the output
  bool scale_to_bounds = false;
  if (settings.fit_to_bounds &&
      ((page_width > dest->width()) || (page_height > dest->height()))) {
    scale_to_bounds = true;
  } else if (settings.stretch_to_bounds &&
             ((page_width < dest->width()) || (page_height < dest->height()))) {
    scale_to_bounds = true;
  }

  if (scale_to_bounds) {
    // If we need to maintain aspect ratio, calculate the actual width and
    // height.
    if (settings.keep_aspect_ratio) {
      double scale_factor_x = page_width;
      scale_factor_x /= dest->width();
      double scale_factor_y = page_height;
      scale_factor_y /= dest->height();
      if (scale_factor_x > scale_factor_y) {
        dest->set_height(page_height / scale_factor_x);
      } else {
        dest->set_width(page_width / scale_factor_y);
      }
    }
  } else {
    // We are not scaling to bounds. Draw in the actual page size. If the
    // actual page size is larger than the bounds, the output will be
    // clipped.
    dest->set_width(page_width);
    dest->set_height(page_height);
  }

  if (settings.center_in_bounds) {
    pp::Point offset((settings.bounds.width() - dest->width()) / 2,
                     (settings.bounds.height() - dest->height()) / 2);
    dest->Offset(offset);
  }
  return rotate;
}

}  // namespace

#if defined(OS_WIN)
bool PDFiumEngineExports::RenderPDFPageToDC(const void* pdf_buffer,
                                            int buffer_size,
                                            int page_number,
                                            const RenderingSettings& settings,
                                            HDC dc) {
  FPDF_DOCUMENT doc = FPDF_LoadMemDocument(pdf_buffer, buffer_size, NULL);
  if (!doc)
    return false;
  FPDF_PAGE page = FPDF_LoadPage(doc, page_number);
  if (!page) {
    FPDF_CloseDocument(doc);
    return false;
  }
  RenderingSettings new_settings = settings;
  // calculate the page size
  if (new_settings.dpi_x == -1)
    new_settings.dpi_x = GetDeviceCaps(dc, LOGPIXELSX);
  if (new_settings.dpi_y == -1)
    new_settings.dpi_y = GetDeviceCaps(dc, LOGPIXELSY);

  pp::Rect dest;
  int rotate = CalculatePosition(page, new_settings, &dest);

  int save_state = SaveDC(dc);
  // The caller wanted all drawing to happen within the bounds specified.
  // Based on scale calculations, our destination rect might be larger
  // than the bounds. Set the clip rect to the bounds.
  IntersectClipRect(dc, settings.bounds.x(), settings.bounds.y(),
                    settings.bounds.x() + settings.bounds.width(),
                    settings.bounds.y() + settings.bounds.height());

  // A temporary hack. PDFs generated by Cairo (used by Chrome OS to generate
  // a PDF output from a webpage) result in very large metafiles and the
  // rendering using FPDF_RenderPage is incorrect. In this case, render as a
  // bitmap. Note that this code does not kick in for PDFs printed from Chrome
  // because in that case we create a temp PDF first before printing and this
  // temp PDF does not have a creator string that starts with "cairo".
  base::string16 creator;
  size_t buffer_bytes = FPDF_GetMetaText(doc, "Creator", NULL, 0);
  if (buffer_bytes > 1) {
    FPDF_GetMetaText(doc, "Creator", WriteInto(&creator, buffer_bytes),
                     buffer_bytes);
  }
  bool use_bitmap = false;
  if (StartsWith(creator, L"cairo", false))
    use_bitmap = true;

  // Another temporary hack. Some PDFs seems to render very slowly if
  // FPDF_RenderPage is directly used on a printer DC. I suspect it is
  // because of the code to talk Postscript directly to the printer if
  // the printer supports this. Need to discuss this with PDFium. For now,
  // render to a bitmap and then blit the bitmap to the DC if we have been
  // supplied a printer DC.
  int device_type = GetDeviceCaps(dc, TECHNOLOGY);
  if (use_bitmap ||
      (device_type == DT_RASPRINTER) || (device_type == DT_PLOTTER)) {
    FPDF_BITMAP bitmap = FPDFBitmap_Create(dest.width(), dest.height(),
                                           FPDFBitmap_BGRx);
      // Clear the bitmap
    FPDFBitmap_FillRect(bitmap, 0, 0, dest.width(), dest.height(), 0xFFFFFFFF);
    FPDF_RenderPageBitmap(
        bitmap, page, 0, 0, dest.width(), dest.height(), rotate,
        FPDF_ANNOT | FPDF_PRINTING | FPDF_NO_CATCH);
    int stride = FPDFBitmap_GetStride(bitmap);
    BITMAPINFO bmi;
    memset(&bmi, 0, sizeof(bmi));
    bmi.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
    bmi.bmiHeader.biWidth = dest.width();
    bmi.bmiHeader.biHeight = -dest.height();  // top-down image
    bmi.bmiHeader.biPlanes = 1;
    bmi.bmiHeader.biBitCount = 32;
    bmi.bmiHeader.biCompression = BI_RGB;
    bmi.bmiHeader.biSizeImage = stride * dest.height();
    StretchDIBits(dc, dest.x(), dest.y(), dest.width(), dest.height(),
                  0, 0, dest.width(), dest.height(),
                  FPDFBitmap_GetBuffer(bitmap), &bmi, DIB_RGB_COLORS, SRCCOPY);
    FPDFBitmap_Destroy(bitmap);
  } else {
    FPDF_RenderPage(dc, page, dest.x(), dest.y(), dest.width(), dest.height(),
                    rotate, FPDF_ANNOT | FPDF_PRINTING | FPDF_NO_CATCH);
  }
  RestoreDC(dc, save_state);
  FPDF_ClosePage(page);
  FPDF_CloseDocument(doc);
  return true;
}
#endif  // OS_WIN

bool PDFiumEngineExports::RenderPDFPageToBitmap(
    const void* pdf_buffer,
    int pdf_buffer_size,
    int page_number,
    const RenderingSettings& settings,
    void* bitmap_buffer) {
  FPDF_DOCUMENT doc = FPDF_LoadMemDocument(pdf_buffer, pdf_buffer_size, NULL);
  if (!doc)
    return false;
  FPDF_PAGE page = FPDF_LoadPage(doc, page_number);
  if (!page) {
    FPDF_CloseDocument(doc);
    return false;
  }

  pp::Rect dest;
  int rotate = CalculatePosition(page, settings, &dest);

  FPDF_BITMAP bitmap =
      FPDFBitmap_CreateEx(settings.bounds.width(), settings.bounds.height(),
                          FPDFBitmap_BGRA, bitmap_buffer,
                          settings.bounds.width() * 4);
  // Clear the bitmap
  FPDFBitmap_FillRect(bitmap, 0, 0, settings.bounds.width(),
                      settings.bounds.height(), 0xFFFFFFFF);
  // Shift top-left corner of bounds to (0, 0) if it's not there.
  dest.set_point(dest.point() - settings.bounds.point());
  FPDF_RenderPageBitmap(
      bitmap, page, dest.x(), dest.y(), dest.width(), dest.height(), rotate,
      FPDF_ANNOT | FPDF_PRINTING | FPDF_NO_CATCH);
  FPDFBitmap_Destroy(bitmap);
  FPDF_ClosePage(page);
  FPDF_CloseDocument(doc);
  return true;
}

bool PDFiumEngineExports::GetPDFDocInfo(const void* pdf_buffer,
                                        int buffer_size,
                                        int* page_count,
                                        double* max_page_width) {
  FPDF_DOCUMENT doc = FPDF_LoadMemDocument(pdf_buffer, buffer_size, NULL);
  if (!doc)
    return false;
  int page_count_local = FPDF_GetPageCount(doc);
  if (page_count) {
    *page_count = page_count_local;
  }
  if (max_page_width) {
    *max_page_width = 0;
    for (int page_number = 0; page_number < page_count_local; page_number++) {
      double page_width = 0;
      double page_height = 0;
      FPDF_GetPageSizeByIndex(doc, page_number, &page_width, &page_height);
      if (page_width > *max_page_width) {
        *max_page_width = page_width;
      }
    }
  }
  FPDF_CloseDocument(doc);
  return true;
}

bool PDFiumEngineExports::GetPDFPageSizeByIndex(
    const void* pdf_buffer,
    int pdf_buffer_size,
    int page_number,
    double* width,
    double* height) {
  FPDF_DOCUMENT doc = FPDF_LoadMemDocument(pdf_buffer, pdf_buffer_size, NULL);
  if (!doc)
    return false;
  bool success = FPDF_GetPageSizeByIndex(doc, page_number, width, height) != 0;
  FPDF_CloseDocument(doc);
  return success;
}

}  // namespace chrome_pdf