[Media Galleries] Filesystem interface for Mac PTP/MTP devices using ImageCaptureCore (part 3)

chrome/browser/media_gallery/mac/mtp_device_delegate_impl_mac.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.
+
+#include "chrome/browser/media_gallery/mac/mtp_device_delegate_impl_mac.h"
+
+#include "base/memory/scoped_nsobject.h"
+#include "base/sequenced_task_runner.h"
+#include "base/sequenced_task_runner_helpers.h"
+#include "base/threading/sequenced_worker_pool.h"
+#include "chrome/browser/media_gallery/mtp_device_delegate_impl.h"
+#include "chrome/browser/system_monitor/image_capture_device.h"
+#include "chrome/browser/system_monitor/image_capture_device_manager.h"
+#include "chrome/browser/system_monitor/media_storage_util.h"
+#include "content/public/browser/browser_thread.h"
+
+namespace chrome {
+
+// This class handles the UI-thread hand-offs needed to interface
+// with the ImageCapture library. It will forward callbacks to
+// its delegate on the task runner with which it is created. All
+// interactions with it are done on the UI thread, but it may be
+// created/destroyed on another thread.
+class CameraDeviceInterface
+    : public ImageCaptureDeviceListener,
+      public base::SupportsWeakPtr<CameraDeviceInterface> {
+ public:
+  CameraDeviceInterface(MTPDeviceDelegateImplMac* delegate,
+                        base::SequencedTaskRunner* task_runner)
+      : delegate_(delegate),
+        task_runner_(task_runner) {}
+  virtual ~CameraDeviceInterface() {}

[Lei Zhang, 2012/12/22 02:44:35]

Should this be private since CloseCameraSessionAndDelete() is the intended way
to delete this?

[Greg Billock, 2012/12/22 03:11:41]

I had it like that, but then TaskRunner::DeleteSoon won't work. It's convenient
for unit tests to leave it like this, but perhaps that's misleading...

[Lei Zhang, 2013/01/02 23:46:54]

You just need to add: friend class base::DeleteHelper<T>

[Greg Billock, 2013/01/03 22:41:32]

I think I must have switched this around. It's in a scoped ptr in the delegate
class now.

+
+  void OpenCameraSession(const std::string& device_id);
+  void CloseCameraSessionAndDelete();
+
+  void DownloadFile(const std::string& name, const FilePath& local_path);
+
+  // ImageCaptureDeviceListener
+  virtual void ItemAdded(const std::string& name,
+                         const base::PlatformFileInfo& info) OVERRIDE;
+  virtual void NoMoreItems() OVERRIDE;
+  virtual void DownloadedFile(const std::string& name,
+                              base::PlatformFileError error) OVERRIDE;
+  virtual void DeviceRemoved() OVERRIDE;
+
+ private:
+  scoped_nsobject<ImageCaptureDevice> camera_device_;
+
+  // Weak pointer
+  MTPDeviceDelegateImplMac* delegate_;
+
+  // Weak pointer
+  base::SequencedTaskRunner* task_runner_;
+};
+
+void CameraDeviceInterface::OpenCameraSession(const std::string& device_id) {
+  camera_device_.reset(
+      [ImageCaptureDeviceManager::deviceForUUID(device_id) retain]);
+  [camera_device_ setListener:AsWeakPtr()];
+  [camera_device_ open];
+}
+
+void CameraDeviceInterface::CloseCameraSessionAndDelete() {
+  if (camera_device_.get()) {
+    [camera_device_ close];
+    [camera_device_ setListener:base::WeakPtr<CameraDeviceInterface>()];
+  }
+
+  delete this;
+}
+
+void CameraDeviceInterface::DownloadFile(const std::string& name,
+                                         const FilePath& local_path) {
+  [camera_device_ downloadFile:name localPath:local_path];
+}
+
+void CameraDeviceInterface::ItemAdded(const std::string& name,
+                                      const base::PlatformFileInfo& info) {
+  task_runner_->PostTask(FROM_HERE,
+      base::Bind(&MTPDeviceDelegateImplMac::ItemAdded,
+                 base::Unretained(delegate_), name, info));
+}
+
+void CameraDeviceInterface::NoMoreItems() {
+  task_runner_->PostTask(FROM_HERE,
+      base::Bind(&MTPDeviceDelegateImplMac::NoMoreItems,
+                 base::Unretained(delegate_)));
+}
+
+void CameraDeviceInterface::DownloadedFile(const std::string& name,
+                                           base::PlatformFileError error) {
+  task_runner_->PostTask(FROM_HERE,
+      base::Bind(&MTPDeviceDelegateImplMac::DownloadedFile,
+                 base::Unretained(delegate_), name, error));
+}
+
+void CameraDeviceInterface::DeviceRemoved() {
+  [camera_device_ close];
+  camera_device_.reset();
+}
+
+MTPDeviceDelegateImplMac::MTPDeviceDelegateImplMac(
+    const FilePath::StringType& location,
+    base::SequencedTaskRunner* media_task_runner)
+    : root_path_(location),
+      media_task_runner_(media_task_runner),
+      received_all_files_(false) {
+  std::string device_id = FilePath(location).BaseName().value();
+  MediaStorageUtil::Type type;
+// !!! Parse this manually
+  DCHECK(MediaStorageUtil::CrackDeviceId(device_id, &type, &device_id_));
+  DCHECK_EQ(MediaStorageUtil::MAC_IMAGE_CAPTURE, type);
+
+  // Make a synthetic entry for the root of the filesystem.
+  base::PlatformFileInfo info;
+  info.is_directory = true;
+  file_info_[root_path_.value()] = info;
+
+  camera_interface_.reset(new CameraDeviceInterface(this, media_task_runner));
+  content::BrowserThread::PostTask(content::BrowserThread::UI, FROM_HERE,
+      base::Bind(&CameraDeviceInterface::OpenCameraSession,
+                 base::Unretained(camera_interface_.get()),
+                 device_id_));
+}
+
+MTPDeviceDelegateImplMac::~MTPDeviceDelegateImplMac() {
+  DCHECK(media_task_runner_->RunsTasksOnCurrentThread());
+  DCHECK(enumerators_.size() == 0);
+}
+
+base::PlatformFileError MTPDeviceDelegateImplMac::GetFileInfo(
+    const FilePath& file_path,
+    base::PlatformFileInfo* file_info) {
+  base::hash_map<FilePath::StringType,
+                 base::PlatformFileInfo>::const_iterator i =
+      file_info_.find(file_path.value());
+  if (i != file_info_.end()) {
+    file_info->size = i->second.size;
+    file_info->is_directory = i->second.is_directory;
+    file_info->is_symbolic_link = i->second.is_symbolic_link;
+    file_info->last_modified = i->second.last_modified;
+    file_info->last_accessed = i->second.last_accessed;
+    file_info->creation_time = i->second.creation_time;
+    return base::PLATFORM_FILE_OK;
+  } else {
+    return base::PLATFORM_FILE_ERROR_NOT_FOUND;
+  }
+}
+
+scoped_ptr<fileapi::FileSystemFileUtil::AbstractFileEnumerator>
+MTPDeviceDelegateImplMac::CreateFileEnumerator(const FilePath& root,
+                                               bool recursive) {
+  Enumerator* enumerator = new Enumerator(this);
+  enumerators_.push_back(enumerator);
+  return make_scoped_ptr(enumerator)
+      .PassAs<fileapi::FileSystemFileUtil::AbstractFileEnumerator>();
+}
+
+base::PlatformFileError MTPDeviceDelegateImplMac::CreateSnapshotFile(
+    const FilePath& device_file_path,
+    const FilePath& local_path,
+    base::PlatformFileInfo* file_info) {
+  std::string name = device_file_path.BaseName().value();
+  base::PlatformFileError error = GetFileInfo(device_file_path, file_info);
+  if (error != base::PLATFORM_FILE_OK)
+    return error;
+
+  // Set up to wait for download.
+  base::WaitableEvent waiter(true, false);
+  download_events_[name] = &waiter;

[Lei Zhang, 2012/12/22 02:44:35]

You got |download_events_| here, but can there ever be more than 1 download at a
time?

[Greg Billock, 2012/12/22 03:11:41]

I meant to ask you this. Is this always called in the sequenced runner? If not,
I need some mutex gear around these structures. If so, I can simplify it a bit.

[Lei Zhang, 2013/01/02 23:46:54]

I believe that to be the case.

[Greg Billock, 2013/01/03 22:41:32]

OK. Sweetened this a bit.

+  // Start the download in the UI thread.
+  content::BrowserThread::PostTask(content::BrowserThread::UI, FROM_HERE,
+      base::Bind(&CameraDeviceInterface::DownloadFile,
+                 base::Unretained(camera_interface_.get()),
+                 name, local_path));
+  waiter.Wait();
+  download_events_.erase(download_events_.find(name));
+  base::hash_map<std::string, base::PlatformFileError>::iterator iter =
+      download_errors_.find(name);
+  error = iter->second;
+  download_errors_.erase(iter);
+
+  // Modify the last modified time to null. This prevents the time stamp
+  // verification in LocalFileStreamReader.
+  file_info->last_modified = base::Time();
+
+  return error;
+}
+
+void MTPDeviceDelegateImplMac::CancelPendingTasksAndDeleteDelegate() {
+  // Artificially pretend that we have already gotten all items we're going
+  // to get.
+  NoMoreItems();
+
+  // Artificially wake up any downloads pending with an error code.
+  for (base::hash_map<std::string, base::WaitableEvent*>::const_iterator iter =
+           download_events_.begin(); iter != download_events_.end(); ++iter) {
+    download_errors_[iter->first] = base::PLATFORM_FILE_ERROR_FAILED;
+    iter->second->Signal();
+  }
+
+  // Schedule the camera session to be closed and the interface deleted.
+  content::BrowserThread::PostTask(content::BrowserThread::UI, FROM_HERE,
+      base::Bind(&CameraDeviceInterface::CloseCameraSessionAndDelete,
+                 base::Unretained(camera_interface_.release())));
+
+  media_task_runner_->DeleteSoon(FROM_HERE, this);
+}
+
+void MTPDeviceDelegateImplMac::ItemAdded(
+    const std::string& name, const base::PlatformFileInfo& info) {
+  // Make sure if we're canceled and enumerators are awake, that
+  // they will stay consistent. May need to revisit this if we need
+  // notifications of files added after we think we're done.
+  if (received_all_files_)
+    return;
+
+  if (info.is_directory)
+    return;
+  FilePath fp = root_path_.Append(name);
+  file_info_[fp.value()] = info;
+  file_paths_.push_back(fp.value());
+
+  for (std::vector<Enumerator*>::const_iterator iter = enumerators_.begin();
+       iter != enumerators_.end();
+       ++iter) {
+    (*iter)->ItemsChanged();
+  }
+}
+
+void MTPDeviceDelegateImplMac::NoMoreItems() {
+  received_all_files_ = true;
+
+  for (std::vector<Enumerator*>::const_iterator iter = enumerators_.begin();
+       iter != enumerators_.end();
+       ++iter) {
+    (*iter)->ItemsChanged();
+  }
+}
+
+void MTPDeviceDelegateImplMac::DownloadedFile(
+    const std::string& name, base::PlatformFileError error) {
+  // If we're cancelled and deleting, we have already signaled all enumerators.
+  if (!camera_interface_.get())
+    return;
+
+  download_errors_[name] = error;
+  download_events_[name]->Signal();
+}
+
+FilePath MTPDeviceDelegateImplMac::GetFile(size_t index) {
+  if (index >= file_paths_.size())
+    return FilePath();
+  else
+    return FilePath(file_paths_[index]);
+}
+
+bool MTPDeviceDelegateImplMac::HasAllFiles() {
+  return received_all_files_;
+}
+
+void MTPDeviceDelegateImplMac::RemoveEnumerator(Enumerator* enumerator) {
+  for (std::vector<Enumerator*>::iterator iter = enumerators_.begin();
+       iter != enumerators_.end();
+       ++iter) {
+    if (*iter == enumerator) {
+      enumerators_.erase(iter);
+      break;
+    }
+  }
+}
+
+MTPDeviceDelegateImplMac::Enumerator::Enumerator(
+    MTPDeviceDelegateImplMac* delegate)
+    : delegate_(delegate),
+      position_(0),
+      wait_for_items_(false, false) {}
+
+MTPDeviceDelegateImplMac::Enumerator::~Enumerator() {
+  delegate_->RemoveEnumerator(this);
+}
+
+FilePath MTPDeviceDelegateImplMac::Enumerator::Next() {
+  FilePath fp = delegate_->GetFile(position_);
+  while (fp.empty() && !delegate_->HasAllFiles()) {
+    wait_for_items_.Wait();
+    fp = delegate_->GetFile(position_);
+  }
+
+  position_++;
+  return fp;
+}
+
+int64 MTPDeviceDelegateImplMac::Enumerator::Size() {
+  FilePath fp = delegate_->GetFile(position_ - 1);
+  base::PlatformFileInfo info;
+  delegate_->GetFileInfo(fp, &info);
+  return info.size;
+  return 0;
+}
+
+base::Time MTPDeviceDelegateImplMac::Enumerator::LastModifiedTime() {
+  FilePath fp = delegate_->GetFile(position_ - 1);
+  base::PlatformFileInfo info;
+  delegate_->GetFileInfo(fp, &info);
+  return info.last_modified;
+}
+
+bool MTPDeviceDelegateImplMac::Enumerator::IsDirectory() {
+  FilePath fp = delegate_->GetFile(position_ - 1);
+  base::PlatformFileInfo info;
+  delegate_->GetFileInfo(fp, &info);
+  return info.is_directory;
+}
+
+void MTPDeviceDelegateImplMac::Enumerator::ItemsChanged() {
+  wait_for_items_.Signal();
+}
+
+void CreateMTPDeviceDelegate(const std::string& device_location,
+                             base::SequencedTaskRunner* media_task_runner,
+                             const CreateMTPDeviceDelegateCallback& cb) {
+  cb.Run(new MTPDeviceDelegateImplMac(device_location, media_task_runner));
+}
+
+}  // namespace chrome
+