Move MTPDeviceDelegateImplLinux worker classes to its own files.

chrome/browser/media_gallery/linux/mtp_open_storage_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.
+
+// This class opens the media transfer protocol (MTP) storage device for
+// communication. This class is created, destroyed and operated on the blocking
+// thread. It may take a while to open the device for communication.
+
+#ifndef CHROME_BROWSER_MEDIA_GALLERY_LINUX_MTP_OPEN_STORAGE_WORKER_H_
+#define CHROME_BROWSER_MEDIA_GALLERY_LINUX_MTP_OPEN_STORAGE_WORKER_H_
+
+#include <string>
+
+#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 MTPOpenStorageWorker>
+    MTPOpenStorageWorkerDeleter;
+
+// Worker class to open a MTP device for communication. This class is
+// instantiated and destructed on |media_task_runner_|. In order to post a
+// request on Dbus thread, the caller should run on UI thread. Therefore, this
+// class posts the open device request on UI thread and receives the response
+// on UI thread.
+class MTPOpenStorageWorker
+    : public base::RefCountedThreadSafe<MTPOpenStorageWorker,
+                                        MTPOpenStorageWorkerDeleter> {
+ public:
+  // Constructed on |media_task_runner_| thread.
+  MTPOpenStorageWorker(const std::string& name,
+                       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();
+
+  // Returns a device handle string if the OpenStorage() request was
+  // successfully completed or an empty string otherwise.
+  const std::string& device_handle() const { return device_handle_; }
+
+  // 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<MTPOpenStorageWorker>;
+  friend class base::DeleteHelper<MTPOpenStorageWorker>;
+  friend class base::RefCountedThreadSafe<MTPOpenStorageWorker,
+                                          MTPOpenStorageWorkerDeleter>;
+
+  // Destructed via MTPOpenStorageWorkerDeleter struct.
+  virtual ~MTPOpenStorageWorker();
+
+  // Dispatches a request to MediaTransferProtocolManager to open the MTP
+  // storage for communication. This is called on UI thread.
+  void DoWorkOnUIThread();
+
+  // Query callback for DoWorkOnUIThread(). |error| is set to true if the device
+  // did not open successfully. This function signals to unblock
+  // |media_task_runner_|.
+  void OnDidWorkOnUIThread(const std::string& device_handle, bool error);
+
+  // The MTP device storage name.
+  const std::string storage_name_;
+
+  // Stores 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_;
+
+  // Stores the result of OpenStorage() request.
+  std::string device_handle_;
+
+  // 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(MTPOpenStorageWorker);
+};
+
+}  // namespace chrome
+
+#endif  // CHROME_BROWSER_MEDIA_GALLERY_LINUX_MTP_OPEN_STORAGE_WORKER_H_