1// Copyright (c) 2011 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/ui/webui/screenshot_source.h"
6
7#include "base/file_util.h"
8#include "base/memory/ref_counted_memory.h"
9#include "base/path_service.h"
10#include "base/synchronization/waitable_event.h"
11#include "base/task.h"
12#include "chrome/common/chrome_paths.h"
13#include "chrome/common/url_constants.h"
14#include "content/browser/browser_thread.h"
15
16static const char kCurrentScreenshot[] = "current";
17#if defined(OS_CHROMEOS)
18static const char kSavedScreenshots[] = "saved/";
19#endif
20
21static const char kScreenshotsRelativePath[] = "/Screenshots/";
22
23#if defined(OS_CHROMEOS)
24// Read the file from the screenshots directory into the read_bytes vector.
25void ReadScreenshot(const std::string& filename,
26                   std::vector<unsigned char>* read_bytes,
27                   base::WaitableEvent* read_complete) {
28  read_bytes->clear();
29
30  FilePath fileshelf_path;
31  if (!PathService::Get(chrome::DIR_DEFAULT_DOWNLOADS, &fileshelf_path)) {
32    read_complete->Signal();
33    return;
34  }
35
36  FilePath file(fileshelf_path.value() + std::string(kScreenshotsRelativePath) +
37                filename);
38
39  int64 file_size = 0;
40  if (!file_util::GetFileSize(file, &file_size)) {
41    read_complete->Signal();
42    return;
43  }
44
45  // expand vector to file size
46  read_bytes->resize(file_size);
47  // read file into the vector
48  int bytes_read = 0;
49  if (!(bytes_read = file_util::ReadFile(file,
50                                         reinterpret_cast<char*>(
51                                             &read_bytes->front()),
52                                             static_cast<int>(file_size))))
53    read_bytes->clear();
54
55  // We're done, if successful, read_bytes will have the data
56  // otherwise, it'll be empty.
57  read_complete->Signal();
58}
59
60// Get a saved screenshot - read on the FILE thread.
61std::vector<unsigned char> GetSavedScreenshot(std::string filename) {
62  base::WaitableEvent read_complete(true, false);
63  std::vector<unsigned char> bytes;
64  BrowserThread::PostTask(BrowserThread::FILE, FROM_HERE,
65                          NewRunnableFunction(&ReadScreenshot, filename,
66                                              &bytes, &read_complete));
67  read_complete.Wait();
68  return bytes;
69}
70#endif
71
72std::vector<unsigned char> ScreenshotSource::GetScreenshot(
73    const std::string& full_path) {
74  // Strip the query param value - we only use it as a hack to ensure our
75  // image gets reloaded instead of being pulled from the browser cache
76  std::string path = full_path.substr(0, full_path.find_first_of("?"));
77  if (path == kCurrentScreenshot) {
78    return current_screenshot_;
79#if defined(OS_CHROMEOS)
80  } else if (path.compare(0, strlen(kSavedScreenshots),
81                          kSavedScreenshots) == 0) {
82    // Split the saved screenshot filename from the path
83    std::string filename = path.substr(strlen(kSavedScreenshots));
84
85    return GetSavedScreenshot(filename);
86#endif
87  } else {
88    std::vector<unsigned char> ret;
89    // TODO(rkc): Weird vc bug, return std::vector<unsigned char>() causes
90    // the object assigned to the return value of this function magically
91    // change it's address 0x0; look into this eventually.
92    return ret;
93  }
94}
95
96ScreenshotSource::ScreenshotSource(
97    std::vector<unsigned char>* current_screenshot)
98    : DataSource(chrome::kChromeUIScreenshotPath, MessageLoop::current()) {
99  // Setup the last screenshot taken.
100  if (current_screenshot)
101    current_screenshot_ = *current_screenshot;
102  else
103    current_screenshot_.clear();
104}
105
106ScreenshotSource::~ScreenshotSource() {}
107
108void ScreenshotSource::StartDataRequest(const std::string& path,
109                                            bool is_incognito,
110                                            int request_id) {
111  SendResponse(request_id, new RefCountedBytes(GetScreenshot(path)));
112}
113
114std::string ScreenshotSource::GetMimeType(const std::string&) const {
115  // We need to explicitly return a mime type, otherwise if the user tries to
116  // drag the image they get no extension.
117  return "image/png";
118}
119