Move MTPDeviceDelegateImplLinux worker classes to its own files.

chrome/browser/media_gallery/linux/read_mtp_file_worker.h

+// 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.
+
+#ifndef CHROME_BROWSER_MEDIA_GALLERY_LINUX_READ_MTP_FILE_WORKER_H_
+#define CHROME_BROWSER_MEDIA_GALLERY_LINUX_READ_MTP_FILE_WORKER_H_
+
+#include <string>
+
+#include "base/file_path.h"
+#include "base/memory/ref_counted.h"
+#include "base/sequenced_task_runner_helpers.h"
+#include "base/synchronization/cancellation_flag.h"
+#include "chrome/browser/media_gallery/linux/mtp_device_operations_utils.h"
+
+namespace base {
+class SequencedTaskRunner;
+class WaitableEvent;
+}
+
+namespace chrome {
+
+typedef struct WorkerDeleter<class ReadMTPFileWorker> ReadMTPFileWorkerDeleter;
+
+// Worker class to read media device file data given a file |path|.
+class ReadMTPFileWorker
+    : public base::RefCountedThreadSafe<ReadMTPFileWorker,
+                                        ReadMTPFileWorkerDeleter> {
+ public:
+  // Constructed on |media_task_runner_| thread.
+  ReadMTPFileWorker(const std::string& handle,
+                    const std::string& src_path,
+                    uint32 total_size,
+                    const FilePath& dest_path,
+                    base::SequencedTaskRunner* task_runner,
+                    base::WaitableEvent* task_completed_event,
+                    base::WaitableEvent* shutdown_event);
+
+  // This function is invoked on |media_task_runner_| to post the task on UI
+  // thread. This blocks the |media_task_runner_| until the task is complete.
+  void Run();
+
+  bool Succeeded() const;
+
+  // Returns the |media_task_runner_| associated with this worker object.
+  // This function is exposed for WorkerDeleter struct to access the
+  // |media_task_runner_|.
+  base::SequencedTaskRunner* media_task_runner() const {
+    return media_task_runner_.get();
+  }
+
+ private:
+  friend struct WorkerDeleter<ReadMTPFileWorker>;
+  friend class base::DeleteHelper<ReadMTPFileWorker>;
+  friend class base::RefCountedThreadSafe<ReadMTPFileWorker,
+                                          ReadMTPFileWorkerDeleter>;
+
+  // Destructed via ReadMTPFileWorkerDeleter.
+  virtual ~ReadMTPFileWorker();
+
+  // Dispatches a request to MediaTransferProtocolManager to get the media file
+  // contents.
+  void DoWorkOnUIThread();
+
+  // Query callback for DoWorkOnUIThread(). On success, |data| has the media
+  // file contents. On failure, |error| is set to true. This function signals
+  // to unblock |media_task_runner_|.
+  void OnDidWorkOnUIThread(const std::string& data, bool error);
+
+  uint32 BytesToRead() const;
+
+  // The device unique identifier to query the device.
+  const std::string device_handle_;
+
+  // The media device file path.
+  const std::string src_path_;
+
+  // Number of bytes to read.
+  const uint32 total_bytes_;
+
+  // Where to write the data read from the device.
+  const FilePath dest_path_;
+
+  /****************************************************************************
+   * The variables below are accessed on both |media_task_runner_| and the UI
+   * thread. However, there's no concurrent access because the UI thread is in a
+   * blocked state when access occurs on |media_task_runner_|.
+   */
+
+  // Number of bytes read from the device.
+  uint32 bytes_read_;
+
+  // Temporary data storage.
+  std::string data_;
+
+  // Whether an error occurred during file transfer.
+  bool error_occurred_;
+
+  /***************************************************************************/
+
+  // A reference to |media_task_runner_| to destruct this object on the correct
+  // thread.
+  scoped_refptr<base::SequencedTaskRunner> media_task_runner_;
+
+  // |media_task_runner_| can wait on this event until the required operation
+  // is complete.
+  // TODO(kmadhusu): Remove this WaitableEvent after modifying the
+  // DeviceMediaFileUtil functions as asynchronous functions.
+  base::WaitableEvent* on_task_completed_event_;
+
+  // Stores a reference to waitable event associated with the shut down message.
+  base::WaitableEvent* on_shutdown_event_;
+
+  // Set to ignore the request results. This will be set when
+  // MTPDeviceDelegateImplLinux object is about to be deleted.
+  // |on_task_completed_event_| and |on_shutdown_event_| should not be
+  // dereferenced when this is set.
+  base::CancellationFlag cancel_tasks_flag_;
+
+  DISALLOW_COPY_AND_ASSIGN(ReadMTPFileWorker);
+};
+
+}  // namespace chrome
+
+#endif  // CHROME_BROWSER_MEDIA_GALLERY_LINUX_READ_MTP_FILE_WORKER_H_