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#ifndef CHROME_BROWSER_MEDIA_GALLERIES_FILEAPI_SAFE_MEDIA_METADATA_PARSER_H_
6#define CHROME_BROWSER_MEDIA_GALLERIES_FILEAPI_SAFE_MEDIA_METADATA_PARSER_H_
7
8#include <string>
9#include <vector>
10
11#include "base/callback.h"
12#include "base/compiler_specific.h"
13#include "base/memory/scoped_ptr.h"
14#include "base/memory/weak_ptr.h"
15#include "chrome/common/extensions/api/media_galleries.h"
16#include "chrome/common/media_galleries/metadata_types.h"
17#include "content/public/browser/utility_process_host.h"
18#include "content/public/browser/utility_process_host_client.h"
19
20namespace IPC {
21class Message;
22}
23
24class Profile;
25
26namespace metadata {
27
28// Parses the media metadata of a Blob safely in a utility process. This class
29// expects the MIME type of the Blob to be already determined. It spawns a
30// utility process to do further MIME-type specific metadata extraction.
31// All public methods and callbacks of this class run on the UI thread.
32class SafeMediaMetadataParser : public content::UtilityProcessHostClient {
33 public:
34  // |metadata_dictionary| is owned by the callback.
35  typedef base::Callback<
36      void(bool parse_success,
37           scoped_ptr<base::DictionaryValue> metadata_dictionary,
38           scoped_ptr<std::vector<AttachedImage> > attached_images)>
39      DoneCallback;
40
41  SafeMediaMetadataParser(Profile* profile, const std::string& blob_uuid,
42                          int64 blob_size, const std::string& mime_type,
43                          bool get_attached_images);
44
45  // Should be called on the UI thread. |callback| also runs on the UI thread.
46  void Start(const DoneCallback& callback);
47
48 private:
49  enum ParserState {
50    INITIAL_STATE,
51    STARTED_PARSING_STATE,
52    FINISHED_PARSING_STATE,
53  };
54
55  // Private because content::UtilityProcessHostClient is ref-counted.
56  virtual ~SafeMediaMetadataParser();
57
58  // Launches the utility process.  Must run on the IO thread.
59  void StartWorkOnIOThread(const DoneCallback& callback);
60
61  // Notification from the utility process when it finishes parsing metadata.
62  // Runs on the IO thread.
63  void OnParseMediaMetadataFinished(
64      bool parse_success, const base::DictionaryValue& metadata_dictionary,
65      const std::vector<AttachedImage>& attached_images);
66
67  // Sequence of functions that bounces from the IO thread to the UI thread to
68  // read the blob data, then sends the data back to the utility process.
69  void OnUtilityProcessRequestBlobBytes(int64 request_id, int64 byte_start,
70                                        int64 length);
71  void StartBlobReaderOnUIThread(int64 request_id, int64 byte_start,
72                                 int64 length);
73  void OnBlobReaderDoneOnUIThread(int64 request_id,
74                                  scoped_ptr<std::string> data,
75                                  int64 /* blob_total_size */);
76  void FinishRequestBlobBytes(int64 request_id, scoped_ptr<std::string> data);
77
78  // UtilityProcessHostClient implementation.
79  // Runs on the IO thread.
80  virtual void OnProcessCrashed(int exit_code) OVERRIDE;
81  virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
82
83  // All member variables are only accessed on the IO thread.
84  Profile* const profile_;
85  const std::string blob_uuid_;
86  const int64 blob_size_;
87  const std::string mime_type_;
88  bool get_attached_images_;
89
90  DoneCallback callback_;
91
92  base::WeakPtr<content::UtilityProcessHost> utility_process_host_;
93
94  // Verifies the messages from the utility process came at the right time.
95  // Initialized on the UI thread, but only accessed on the IO thread.
96  ParserState parser_state_;
97
98  DISALLOW_COPY_AND_ASSIGN(SafeMediaMetadataParser);
99};
100
101}  // namespace metadata
102
103#endif  // CHROME_BROWSER_MEDIA_GALLERIES_FILEAPI_SAFE_MEDIA_METADATA_PARSER_H_
104