[Media Gallery] Added code to support mtp device media file system on Windows.

chrome/browser/media_gallery/win/recursive_mtp_device_object_enumerator.cc

+// 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.
+//
+// RecursiveMTPDeviceObjectEnumerator implementation.
+
+#include "chrome/browser/media_gallery/win/recursive_mtp_device_object_enumerator.h"
+
+#include "base/file_path.h"
+#include "base/threading/sequenced_worker_pool.h"
+#include "chrome/browser/media_gallery/win/mtp_device_object_entry.h"
+#include "chrome/browser/media_gallery/win/mtp_device_object_enumerator.h"
+#include "chrome/browser/media_gallery/win/mtp_device_operations_util.h"
+#include "content/public/browser/browser_thread.h"
+
+namespace chrome {
+
+RecursiveMTPDeviceObjectEnumerator::RecursiveMTPDeviceObjectEnumerator(
+    IPortableDevice* device,
+    const MTPDeviceObjectEntries& entries)
+    : device_(device),
+      object_entries_(entries),
+      object_entry_iter_(object_entries_.begin()) {
+  DCHECK(content::BrowserThread::GetBlockingPool()->RunsTasksOnCurrentThread());
+  current_enumerator_.reset(new MTPDeviceObjectEnumerator(entries));
+}
+
+RecursiveMTPDeviceObjectEnumerator::~RecursiveMTPDeviceObjectEnumerator() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+}
+
+FilePath RecursiveMTPDeviceObjectEnumerator::Next() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  FilePath path = current_enumerator_->Next();
+  if (!path.empty())
+    return path;
+
+  // We reached the end.
+  if (object_entry_iter_ == object_entries_.end())
+    return FilePath();
+
+  // Enumerate subdirectories of the next media object entry.
+  MTPDeviceObjectEntry next_object_entry = *object_entry_iter_;
+  ++object_entry_iter_;
+
+  MTPDeviceObjectEntries object_entries;
+  bool success = MTPDeviceOperationsUtil::GetDirectoryEntries(
+      device_.get(), next_object_entry.object_id, &object_entries);
+
+  if (!success || object_entries.empty()) {
+    current_enumerator_.reset(
+        new fileapi::FileSystemFileUtil::EmptyFileEnumerator());
+  } else {
+    current_enumerator_.reset(
+        new MTPDeviceObjectEnumerator(object_entries));
+  }
+  return current_enumerator_->Next();
+}
+
+int64 RecursiveMTPDeviceObjectEnumerator::Size() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  return current_enumerator_->Size();
+}
+
+bool RecursiveMTPDeviceObjectEnumerator::IsDirectory() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  return current_enumerator_->IsDirectory();
+}
+
+base::Time RecursiveMTPDeviceObjectEnumerator::LastModifiedTime() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  return current_enumerator_->LastModifiedTime();
+}
+
+}  // namespace chrome