[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) 2013 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/thread_restrictions.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),
+      curr_object_entries_(entries),
+      object_entry_iter_(curr_object_entries_.begin()) {
+  base::ThreadRestrictions::AssertIOAllowed();
+  current_enumerator_.reset(new MTPDeviceObjectEnumerator(entries));
+}
+
+RecursiveMTPDeviceObjectEnumerator::~RecursiveMTPDeviceObjectEnumerator() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+}
+
+FilePath RecursiveMTPDeviceObjectEnumerator::Next() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  MaybeUpdateCurrentObjectList();
+  if (curr_object_entries_.empty())
+    return FilePath();
+
+  DCHECK(object_entry_iter_ != curr_object_entries_.end());
+  const MTPDeviceObjectEntry& current_object_entry = *(object_entry_iter_++);
+  if (current_object_entry.is_directory) {
+    // If |current_object_entry| is a directory, add it to
+    // |unparsed_directory_object_ids_| to scan after scanning this directory.
+    unparsed_directory_object_ids_.push(current_object_entry.object_id);
+  }
+  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();
+}
+
+void RecursiveMTPDeviceObjectEnumerator::MaybeUpdateCurrentObjectList() {
+  if (object_entry_iter_ != curr_object_entries_.end())
+    return;
+
+  curr_object_entries_.clear();
+  while (curr_object_entries_.empty() &&
+         !unparsed_directory_object_ids_.empty()) {
+    DirectoryObjectId object_id = unparsed_directory_object_ids_.front();
+    unparsed_directory_object_ids_.pop();
+    if (media_transfer_protocol::GetDirectoryEntries(device_.get(), object_id,
+                                                     &curr_object_entries_) &&
+        !curr_object_entries_.empty()) {
+      current_enumerator_.reset(
+          new MTPDeviceObjectEnumerator(curr_object_entries_));
+      break;
+    }
+  }
+
+  if (curr_object_entries_.empty()) {
+    // Parsed all the objects.
+    current_enumerator_.reset(
+        new fileapi::FileSystemFileUtil::EmptyFileEnumerator());
+  }
+  object_entry_iter_ = curr_object_entries_.begin();
+}
+
+}  // namespace chrome