chrome/utility/media_galleries/media_metadata_parser.h

   1 // Copyright 2013 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 #ifndef CHROME_UTILITY_MEDIA_GALLERIES_MEDIA_METADATA_PARSER_H_
   6 #define CHROME_UTILITY_MEDIA_GALLERIES_MEDIA_METADATA_PARSER_H_
   7
   8 #include <string>
   9 #include <vector>
  10
  11 #include "base/callback.h"
  12 #include "base/memory/scoped_ptr.h"
  13 #include "chrome/common/extensions/api/media_galleries.h"
  14 #include "chrome/common/media_galleries/metadata_types.h"
  15
  16 namespace base {
  17 class Thread;
  18 }
  19
  20 namespace media {
  21 class DataSource;
  22 }
  23
  24 namespace metadata {
  25
  26 // This class takes a MIME type and data source and parses its metadata. It
  27 // handles audio, video, and images. It delegates its operations to FFMPEG,
  28 // libexif, etc. This class lives and operates on the utility thread of the
  29 // utility process, as we wish to sandbox potentially dangerous operations
  30 // on user-provided data.
  31 class MediaMetadataParser {
  32  public:
  33   typedef extensions::api::media_galleries::MediaMetadata MediaMetadata;
  34   typedef base::Callback<
  35       void(const MediaMetadata& metadata,
  36            const std::vector<AttachedImage>& attached_images)>
  37   MetadataCallback;
  38
  39   // Does not take ownership of |source|. Caller is responsible for ensuring
  40   // that |source| outlives this object.
  41   MediaMetadataParser(media::DataSource* source, const std::string& mime_type,
  42                       bool get_attached_images);
  43
  44   ~MediaMetadataParser();
  45
  46   // |callback| is called on same message loop.
  47   void Start(const MetadataCallback& callback);
  48
  49  private:
  50   // Only accessed on |media_thread_| from this class.
  51   media::DataSource* const source_;
  52
  53   const std::string mime_type_;
  54
  55   bool get_attached_images_;
  56
  57   // Thread that blocking media parsing operations run on while the main thread
  58   // handles messages from the browser process.
  59   // TODO(tommycli): Replace with a reference to a WorkerPool if we ever use
  60   // this class in batch mode.
  61   scoped_ptr<base::Thread> media_thread_;
  62
  63   DISALLOW_COPY_AND_ASSIGN(MediaMetadataParser);
  64 };
  65
  66 }  // namespace metadata
  67
  68 #endif  // CHROME_UTILITY_MEDIA_GALLERIES_MEDIA_METADATA_PARSER_H_