src/chrome/browser/extensions/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 "chrome/browser/extensions/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 api {
  25
  26 DocumentScanScanFunction::DocumentScanScanFunction()
  27     : document_scan_interface_(DocumentScanInterface::CreateInstance()) {}
  28
  29 DocumentScanScanFunction::~DocumentScanScanFunction() {}
  30
  31 bool DocumentScanScanFunction::Prepare() {
  32   set_work_thread_id(BrowserThread::FILE);
  33   params_ = document_scan::Scan::Params::Create(*args_);
  34   EXTENSION_FUNCTION_VALIDATE(params_.get());
  35   return true;
  36 }
  37
  38 void DocumentScanScanFunction::AsyncWorkStart() {
  39   if (!user_gesture()) {
  40     error_ = kUserGestureRequiredError;
  41     AsyncWorkCompleted();
  42     return;
  43   }
  44
  45   // Add a reference, which is balanced in OnScannerListReceived to keep the
  46   // object around and allow the callback to be invoked.
  47   AddRef();
  48
  49   document_scan_interface_->ListScanners(
  50       base::Bind(&DocumentScanScanFunction::OnScannerListReceived,
  51                  base::Unretained(this)));
  52 }
  53
  54 void DocumentScanScanFunction::OnScannerListReceived(
  55     const std::vector<DocumentScanInterface::ScannerDescription>&
  56         scanner_descriptions,
  57     const std::string& error) {
  58   std::vector<DocumentScanInterface::ScannerDescription>::const_iterator
  59       scanner_i = scanner_descriptions.begin();
  60
  61   // If no |scanner_descriptions| is empty, this is an error.  If no
  62   // MIME types are specified, the first scanner is chosen.  If MIME
  63   // types are specified, the first scanner that supports one of these
  64   // MIME types is selected.
  65   if (params_->options.mime_types) {
  66     std::vector<std::string>& mime_types = *params_->options.mime_types.get();
  67     for (; scanner_i != scanner_descriptions.end(); ++scanner_i) {
  68       if (std::find(mime_types.begin(), mime_types.end(),
  69                     scanner_i->image_mime_type) != mime_types.end()) {
  70         break;
  71       }
  72     }
  73   }
  74
  75   if (scanner_i == scanner_descriptions.end()) {
  76     error_ = kScannerNotAvailable;
  77     AsyncWorkCompleted();
  78
  79     // Balance the AddRef in AsyncWorkStart().
  80     Release();
  81     return;
  82   }
  83
  84   // TODO(pstew): Call a delegate method here to select a scanner and options.
  85
  86   document_scan_interface_->Scan(
  87       scanner_i->name,
  88       DocumentScanInterface::kScanModeColor,
  89       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
  99   // TODO(pstew): Enlist a delegate to display received scan in the UI
 100   //  and confirm that this scan should be sent to the caller.  If this
 101   // is a multi-page scan, provide a means for adding additional scanned
 102   // images up to the requested limit.
 103
 104   if (error.empty()) {
 105     document_scan::ScanResults scan_results;
 106     if (!scanned_image.empty()) {
 107       scan_results.data_urls.push_back(scanned_image);
 108     }
 109     scan_results.mime_type = mime_type;
 110     results_ = document_scan::Scan::Results::Create(scan_results);
 111   }
 112   error_ = error;
 113   AsyncWorkCompleted();
 114
 115   // Balance the AddRef in AsyncWorkStart().
 116   Release();
 117 }
 118
 119 bool DocumentScanScanFunction::Respond() {
 120   return error_.empty();
 121 }
 122
 123 }  // namespace api
 124
 125 }  // namespace extensions