Create a broker interface for the new Mojo EDK so that the browser can create and duplicate messa...

mojo/edk/system/child_token_serializer_win.h

+// Copyright 2015 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 MOJO_EDK_SYSTEM_CHILD_TOKEN_SERIALIZER_WIN_H_
+#define MOJO_EDK_SYSTEM_CHILD_TOKEN_SERIALIZER_WIN_H_
+
+#include "base/memory/singleton.h"
+#include "base/synchronization/lock_impl.h"
+#include "mojo/edk/embedder/scoped_platform_handle.h"
+#include "mojo/edk/system/system_impl_export.h"
+#include "mojo/edk/system/token_serializer_win.h"
+
+namespace mojo {
+namespace edk {
+struct TokenSerializerMessage;
+
+// An implementation of TokenSerializer used in (sandboxed) child processes. It
+// talks over sync IPCs to the (unsandboxed) parent process (specifically,
+// ParentTokenSerializer) to convert handles to tokens and vice versa.
+class MOJO_SYSTEM_IMPL_EXPORT ChildTokenSerializer : public TokenSerializer {
+ public:
+  static ChildTokenSerializer* GetInstance();
+
+  // Passes the platform handle that is used to talk to ParentTokenSerializer.
+  void SetParentTokenSerializerHandle(ScopedPlatformHandle handle);
+
+  // TokenSerializer implementation:
+  void CreatePlatformChannelPair(ScopedPlatformHandle* server,
+                                 ScopedPlatformHandle* client) override;
+  void HandleToToken(const PlatformHandle* platform_handles,
+                     size_t count,
+                     uint64_t* tokens) override;
+  void TokenToHandle(const uint64_t* tokens,
+                     size_t count,
+                     PlatformHandle* handles) override;
+
+ private:
+  friend struct base::DefaultSingletonTraits<ChildTokenSerializer>;
+
+  ChildTokenSerializer();
+  ~ChildTokenSerializer() override;
+
+  // Helper method to write the given message and read back the result.
+  bool WriteAndReadResponse(TokenSerializerMessage* message,
+                            void* response,
+                            uint32_t response_size);
+
+  // Guards access to below.
+  // We use LockImpl instead of Lock because the latter adds thread checking
+  // that we don't want (since we lock in the constructor and unlock on another
+  // thread.
+  base::internal::LockImpl lock_;

[rickyz (no longer on Chrome), 2015/11/24 00:30:43]

Unlocking this on a different thread looks like it should work fine on Windows
(which I guess is all that matters here), but the API doesn't appear to
guarantee supporting it - the Linux version would error, I think.

+  ScopedPlatformHandle handle_;
+};
+
+}  // namespace edk
+}  // namespace mojo
+
+#endif  // MOJO_EDK_SYSTEM_CHILD_TOKEN_SERIALIZER_WIN_H_