extensions/browser/api/document_scan/document_scan_api.cc

   1 // Copyright 2014 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 "extensions/browser/api/document_scan/document_scan_api.h"
   6
   7 #include <algorithm>
   8
   9 #include "content/public/browser/browser_thread.h"
  10 #include "extensions/browser/extension_system.h"
  11
  12 using content::BrowserThread;
  13
  14 namespace {
  15
  16 const char kScannerNotAvailable[] = "Scanner not available";
  17 const char kUserGestureRequiredError[] =
  18     "User gesture required to perform scan";
  19
  20 }  // namespace
  21
  22 namespace extensions {
  23
  24 namespace core_api {
  25
  26 DocumentScanScanFunction::DocumentScanScanFunction()
  27     : document_scan_interface_(DocumentScanInterface::CreateInstance()) {
  28 }
  29
  30 DocumentScanScanFunction::~DocumentScanScanFunction() {
  31 }
  32
  33 bool DocumentScanScanFunction::Prepare() {
  34   set_work_thread_id(BrowserThread::FILE);
  35   params_ = document_scan::Scan::Params::Create(*args_);
  36   EXTENSION_FUNCTION_VALIDATE(params_.get());
  37   return true;
  38 }
  39
  40 void DocumentScanScanFunction::AsyncWorkStart() {
  41   if (!user_gesture()) {
  42     error_ = kUserGestureRequiredError;
  43     AsyncWorkCompleted();
  44     return;
  45   }
  46
  47   // Add a reference, which is balanced in OnScannerListReceived to keep the
  48   // object around and allow the callback to be invoked.
  49   AddRef();
  50
  51   document_scan_interface_->ListScanners(
  52       base::Bind(&DocumentScanScanFunction::OnScannerListReceived,
  53                  base::Unretained(this)));
  54 }
  55
  56 void DocumentScanScanFunction::OnScannerListReceived(
  57     const std::vector<DocumentScanInterface::ScannerDescription>&
  58         scanner_descriptions,
  59     const std::string& error) {
  60   std::vector<DocumentScanInterface::ScannerDescription>::const_iterator
  61       scanner_i = scanner_descriptions.begin();
  62
  63   // If no |scanner_descriptions| is empty, this is an error.  If no
  64   // MIME types are specified, the first scanner is chosen.  If MIME
  65   // types are specified, the first scanner that supports one of these
  66   // MIME types is selected.
  67   if (params_->options.mime_types) {
  68     std::vector<std::string>& mime_types = *params_->options.mime_types.get();
  69     for (; scanner_i != scanner_descriptions.end(); ++scanner_i) {
  70       if (std::find(mime_types.begin(), mime_types.end(),
  71                     scanner_i->image_mime_type) != mime_types.end()) {
  72         break;
  73       }
  74     }
  75   }
  76
  77   if (scanner_i == scanner_descriptions.end()) {
  78     error_ = kScannerNotAvailable;
  79     AsyncWorkCompleted();
  80
  81     // Balance the AddRef in AsyncWorkStart().
  82     Release();
  83     return;
  84   }
  85
  86   // TODO(pstew): Call a delegate method here to select a scanner and options.
  87
  88   document_scan_interface_->Scan(
  89       scanner_i->name, DocumentScanInterface::kScanModeColor, 0,
  90       base::Bind(&DocumentScanScanFunction::OnResultsReceived,
  91                  base::Unretained(this)));
  92 }
  93
  94 void DocumentScanScanFunction::OnResultsReceived(
  95     const std::string& scanned_image,
  96     const std::string& mime_type,
  97     const std::string& error) {
  98   // TODO(pstew): Enlist a delegate to display received scan in the UI
  99   //  and confirm that this scan should be sent to the caller.  If this
 100   // is a multi-page scan, provide a means for adding additional scanned
 101   // images up to the requested limit.
 102
 103   if (error.empty()) {
 104     document_scan::ScanResults scan_results;
 105     if (!scanned_image.empty()) {
 106       scan_results.data_urls.push_back(scanned_image);
 107     }
 108     scan_results.mime_type = mime_type;
 109     results_ = document_scan::Scan::Results::Create(scan_results);
 110   }
 111   error_ = error;
 112   AsyncWorkCompleted();
 113
 114   // Balance the AddRef in AsyncWorkStart().
 115   Release();
 116 }
 117
 118 bool DocumentScanScanFunction::Respond() {
 119   return error_.empty();
 120 }
 121
 122 }  // namespace core_api
 123
 124 }  // namespace extensions