[Media Galleries] Add an ImageCaptureCore listener for Mac. (part 2)

chrome/browser/system_monitor/image_capture_device.mm

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#import "chrome/browser/system_monitor/image_capture_device.h"
+
+#include "base/file_util.h"
+#include "base/system_monitor/system_monitor.h"
+#include "chrome/browser/system_monitor/media_storage_util.h"
+#include "content/public/browser/browser_thread.h"
+
+namespace {
+
+void RenameFile(const FilePath& downloaded_filename,
+                const FilePath& desired_filename,
+                base::PlatformFileError* result) {
+  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::FILE));
+  bool success = file_util::ReplaceFile(downloaded_filename, desired_filename);
+  *result = success ? base::PLATFORM_FILE_OK
+                    : base::PLATFORM_FILE_ERROR_NOT_FOUND;
+}
+
+void ReturnRenameResultToListener(
+    base::WeakPtr<ImageCaptureDeviceListener> listener,
+    const std::string& name,
+    base::PlatformFileError* result) {
+  scoped_ptr<base::PlatformFileError> result_deleter(result);

[sail, 2012/12/20 01:08:24]

I think there's a memory leak here.
If the listener is deleted then this function will never get called and the
result will be leaked.

[Greg Billock, 2012/12/20 16:31:52]

My understanding from docs and looking at the implementation is that
PostTaskAndReply will call this reply closure unconditionally (and on the
calling thread), as soon as the task closure returns.
(base/threading/post_task_and_reply_impl.cc is what eventually ends up handling
this)

[sail, 2012/12/20 18:34:54]

Ahh, you're right.

+  if (listener)
+    listener->DownloadedFile(name, *result);
+}
+
+base::Time NSDateToBaseTime(NSDate* date) {
+  return base::Time::FromDoubleT([date timeIntervalSince1970]);
+}
+
+}  // namespace
+
+@implementation ImageCaptureDevice
+
+- (id)initWithCameraDevice:(ICCameraDevice*)cameraDevice {
+  if ((self = [super init])) {
+    camera_.reset([cameraDevice retain]);
+    [camera_ setDelegate:self];
+  }
+  return self;
+}
+
+- (void)dealloc {
+  // Make sure the session was closed and listener set to null
+  // before destruction.
+  DCHECK(![camera_ delegate]);
+  DCHECK(!listener_);
+  [super dealloc];
+}
+
+- (void)setListener:(base::WeakPtr<ImageCaptureDeviceListener>)listener {
+  listener_ = listener;
+}
+
+- (void)open {
+  DCHECK(listener_);
+  [camera_ requestOpenSession];
+}
+
+- (void)close {
+  [camera_ requestCloseSession];
+  [camera_ setDelegate:nil];
+  listener_.reset();
+}
+
+- (void)downloadFile:(const std::string&)name
+           localPath:(const FilePath&)localPath {
+  // Find the file with that name and start download.
+  for (ICCameraItem* item in [camera_ mediaFiles]) {
+    std::string itemName = base::SysNSStringToUTF8([item name]);
+    if (itemName == name) {
+      // To create save options for ImageCapture, we need to
+      // split the target filename into directory/name
+      // and encode the directory as a URL.
+      NSString* saveDirectory =
+          base::mac::FilePathToNSString(localPath.DirName());
+      NSString* saveFilename =
+          base::mac::FilePathToNSString(localPath.BaseName());
+
+      NSMutableDictionary* options =
+          [NSMutableDictionary dictionaryWithCapacity:3];
+      [options setObject:[NSURL fileURLWithPath:saveDirectory isDirectory:YES]
+                  forKey:ICDownloadsDirectoryURL];
+      [options setObject:saveFilename forKey:ICSaveAsFilename];
+      [options setObject:[NSNumber numberWithBool:YES] forKey:ICOverwrite];
+
+      [camera_ requestDownloadFile:base::mac::ObjCCastStrict<ICCameraFile>(item)
+                           options:options
+                  downloadDelegate:self
+               didDownloadSelector:
+                   @selector(didDownloadFile:error:options:contextInfo:)
+                       contextInfo:NULL];
+      return;
+    }
+  }
+
+  if (listener_)
+    listener_->DownloadedFile(name, base::PLATFORM_FILE_ERROR_NOT_FOUND);
+}
+
+- (void)cameraDevice:(ICCameraDevice*)camera didAddItem:(ICCameraItem*)item {
+  std::string name = base::SysNSStringToUTF8([item name]);
+  base::PlatformFileInfo info;
+  if ([[item UTI] isEqualToString:base::mac::CFToNSCast(kUTTypeFolder)])
+    info.is_directory = true;
+  else
+    info.size = [base::mac::ObjCCastStrict<ICCameraFile>(item) fileSize];
+  info.last_modified = NSDateToBaseTime([item modificationDate]);
+  info.creation_time = NSDateToBaseTime([item creationDate]);
+  info.last_accessed = info.last_modified;
+
+  if (listener_)
+    listener_->ItemAdded(name, info);
+}
+
+- (void)cameraDevice:(ICCameraDevice*)camera didAddItems:(NSArray*)items {
+  for (ICCameraItem* item in items)
+    [self cameraDevice:camera didAddItem:item];
+}
+
+- (void)didRemoveDevice:(ICDevice*)device {
+  device.delegate = NULL;
+  if (listener_)
+    listener_->DeviceRemoved();
+}
+
+// Notifies that a session was opened with the given device; potentially
+// with an error.
+- (void)device:(ICDevice*)device didOpenSessionWithError:(NSError*)error {
+  if (error)
+    [self didRemoveDevice:camera_];
+}
+
+- (void)device:(ICDevice*)device didEncounterError:(NSError*)error {
+  if (error && listener_)
+    listener_->DeviceRemoved();
+}
+
+// When this message is received, all media metadata is now loaded.
+- (void)deviceDidBecomeReadyWithCompleteContentCatalog:(ICDevice*)device {
+  if (listener_)
+    listener_->NoMoreItems();
+}
+
+- (void)didDownloadFile:(ICCameraFile*)file

[sail, 2012/12/20 18:34:54]

now that this code is working could you add a test for this? Either by making
this method public or by calling downloadFile:.

[Greg Billock, 2012/12/20 23:35:26]

Definitely. Now added, along with UI thread checks in this class to make sure
the contracts get followed correctly by clients.

+                  error:(NSError*)error
+                options:(NSDictionary*)options
+            contextInfo:(void*)contextInfo {
+  std::string name = base::SysNSStringToUTF8([file name]);
+
+  if (error) {
+    if (listener_)
+      listener_->DownloadedFile(name, base::PLATFORM_FILE_ERROR_FAILED);
+    return;
+  }
+
+  std::string savedFilename =
+      base::SysNSStringToUTF8([options objectForKey:ICSavedFilename]);
+  std::string saveAsFilename =
+      base::SysNSStringToUTF8([options objectForKey:ICSaveAsFilename]);
+  if (savedFilename == saveAsFilename) {
+    if (listener_)
+      listener_->DownloadedFile(name, base::PLATFORM_FILE_OK);
+    return;
+  }
+
+  // ImageCapture did not save the file into the name we give it in the
+  // options. It picks a new name according to its best lights, so we need
+  // to rename the file.
+  FilePath save_dir(base::SysNSStringToUTF8(
+      [[options objectForKey:ICDownloadsDirectoryURL] path]));
+  FilePath saveAsPath = save_dir.Append(saveAsFilename);
+  FilePath savedPath = save_dir.Append(savedFilename);
+
+  // Shared result value from file-copy closure to tell-listener closure.
+  base::PlatformFileError* copyResult = new base::PlatformFileError();
+  content::BrowserThread::PostTaskAndReply(
+      content::BrowserThread::FILE,
+      FROM_HERE,
+      base::Bind(&RenameFile, savedPath, saveAsPath, copyResult),
+      base::Bind(&ReturnRenameResultToListener, listener_, name, copyResult));
+}
+
+@end  // ImageCaptureDevice