Media Galleries API Metadata: SafeMediaMetadataParser and IPCTunnelDataReader.

chrome/utility/media_galleries/ipc_tunnel_data_reader.cc

Index: chrome/utility/media_galleries/ipc_tunnel_data_reader.cc
diff --git a/chrome/utility/media_galleries/ipc_tunnel_data_reader.cc b/chrome/utility/media_galleries/ipc_tunnel_data_reader.cc
new file mode 100644
index 0000000000000000000000000000000000000000..c5417ca5b777c258cd2f0a7669e52416f1f8d295
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+++ b/chrome/utility/media_galleries/ipc_tunnel_data_reader.cc
@@ -0,0 +1,38 @@
+// Copyright 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.
+
+#include "chrome/utility/media_galleries/ipc_tunnel_data_reader.h"
+
+#include "chrome/common/chrome_utility_messages.h"
+#include "content/public/utility/utility_thread.h"
+
+namespace metadata {
+
+IPCTunnelDataReader::IPCTunnelDataReader() : next_request_id_(0) {}
+
+IPCTunnelDataReader::~IPCTunnelDataReader() {}
+
+void IPCTunnelDataReader::ReadBytes(int64 offset, int64 length,
+                                    const ReadBytesCallback& callback) {
+  int64 request_id = ++next_request_id_;
+  pending_callbacks_[request_id] = callback;
+  content::UtilityThread::Get()->Send(
+      new ChromeUtilityHostMsg_ParseMediaMetadata_RequestBlobBytes(
+          request_id, offset, length));
+}
+
+void IPCTunnelDataReader::ReceiveBytes(int64 request_id,
+                                       const std::string& bytes) {
+  std::map<int64, ReadBytesCallback>::iterator it =
+      pending_callbacks_.find(request_id);
+
+  if (it == pending_callbacks_.end())
+    return;
+
+  it->second.Run(bytes);
+
+  pending_callbacks_.erase(it);
+}
+
+}  // namespace metadata