ui/surface/transport_dib_win.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "ui/surface/transport_dib.h"
   6
   7 #include <windows.h>
   8
   9 #include <limits>
  10
  11 #include "base/logging.h"
  12 #include "base/memory/scoped_ptr.h"
  13 #include "base/sys_info.h"
  14 #include "skia/ext/platform_canvas.h"
  15
  16 TransportDIB::TransportDIB()
  17     : size_(0) {
  18 }
  19
  20 TransportDIB::~TransportDIB() {
  21 }
  22
  23 TransportDIB::TransportDIB(HANDLE handle)
  24     : shared_memory_(handle, false /* read write */),
  25       size_(0) {
  26 }
  27
  28 // static
  29 TransportDIB* TransportDIB::Create(size_t size, uint32 sequence_num) {
  30   TransportDIB* dib = new TransportDIB;
  31
  32   if (!dib->shared_memory_.CreateAnonymous(size)) {
  33     delete dib;
  34     return NULL;
  35   }
  36
  37   dib->size_ = size;
  38   dib->sequence_num_ = sequence_num;
  39
  40   return dib;
  41 }
  42
  43 // static
  44 TransportDIB* TransportDIB::Map(Handle handle) {
  45   scoped_ptr<TransportDIB> dib(CreateWithHandle(handle));
  46   if (!dib->Map())
  47     return NULL;
  48   return dib.release();
  49 }
  50
  51 // static
  52 TransportDIB* TransportDIB::CreateWithHandle(Handle handle) {
  53   return new TransportDIB(handle);
  54 }
  55
  56 // static
  57 bool TransportDIB::is_valid_handle(Handle dib) {
  58   return dib != NULL;
  59 }
  60
  61 // static
  62 bool TransportDIB::is_valid_id(TransportDIB::Id id) {
  63   return is_valid_handle(id.handle);
  64 }
  65
  66 skia::PlatformCanvas* TransportDIB::GetPlatformCanvas(int w, int h) {
  67   // This DIB already mapped the file into this process, but PlatformCanvas
  68   // will map it again.
  69   DCHECK(!memory()) << "Mapped file twice in the same process.";
  70
  71   // We can't check the canvas size before mapping, but it's safe because
  72   // Windows will fail to map the section if the dimensions of the canvas
  73   // are too large.
  74   skia::PlatformCanvas* canvas =
  75       skia::CreatePlatformCanvas(w, h, true, handle(),
  76                                  skia::RETURN_NULL_ON_FAILURE);
  77
  78   // Calculate the size for the memory region backing the canvas.
  79   if (canvas)
  80     size_ = skia::PlatformCanvasStrideForWidth(w) * h;
  81
  82   return canvas;
  83 }
  84
  85 bool TransportDIB::Map() {
  86   if (!is_valid_handle(handle()))
  87     return false;
  88   if (memory())
  89     return true;
  90
  91   if (!shared_memory_.Map(0 /* map whole shared memory segment */)) {
  92     LOG(ERROR) << "Failed to map transport DIB"
  93                << " handle:" << shared_memory_.handle()
  94                << " error:" << ::GetLastError();
  95     return false;
  96   }
  97
  98   size_ = shared_memory_.mapped_size();
  99   return true;
 100 }
 101
 102 void* TransportDIB::memory() const {
 103   return shared_memory_.memory();
 104 }
 105
 106 TransportDIB::Handle TransportDIB::handle() const {
 107   return shared_memory_.handle();
 108 }
 109
 110 TransportDIB::Id TransportDIB::id() const {
 111   return Id(handle(), sequence_num_);
 112 }