Add multiplexing of message pipes in the new EDK.

mojo/edk/system/routed_raw_channel.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_ROUTED_RAW_CHANNEL_H_
+#define MOJO_EDK_SYSTEM_ROUTED_RAW_CHANNEL_H_
+
+#include "base/callback.h"
+#include "base/containers/hash_tables.h"
+#include "base/macros.h"
+#include "base/synchronization/lock.h"
+#include "mojo/edk/embedder/platform_handle_vector.h"
+#include "mojo/edk/embedder/scoped_platform_handle.h"
+#include "mojo/edk/system/broker.h"
+#include "mojo/edk/system/raw_channel.h"
+#include "mojo/edk/system/system_impl_export.h"
+
+namespace mojo {
+namespace edk {
+class RawChannel;
+
+// This class wraps a RawChannel and adds routing on top of it.
+// Non-transferable MessagePipeDispatchers call here, indirectly through the
+// Broker interface, to associate with their pipe_id.
+class RoutedRawChannel : public RawChannel::Delegate {
+ public:
+  RoutedRawChannel(
+      ScopedPlatformHandle handle,
+      const base::Callback<void(RoutedRawChannel*)>& destruct_callback);
+
+  // Connect the given |pipe| with the pipe_id route. Only non-transferable
+  // message pipes can call this, and they can only call it once.
+  void AddRoute(uint64_t pipe_id, MessagePipeDispatcher* pipe);
+
+  // Called when the MessagePipeDispatcher is going away.
+  void RemoveRoute(uint64_t pipe_id, MessagePipeDispatcher* pipe);
+
+  RawChannel* channel() { return channel_; }
+
+ private:
+  friend class base::DeleteHelper<RoutedRawChannel>;
+  ~RoutedRawChannel() override;
+
+  // RawChannel::Delegate implementation:
+  void OnReadMessage(
+        const MessageInTransit::View& message_view,
+        ScopedPlatformHandleVectorPtr platform_handles) override;
+  void OnError(Error error) override;
+
+  RawChannel* channel_;
+
+  base::Lock lock_;  // Guards access to below.
+  base::hash_map<uint64_t, MessagePipeDispatcher*> routes_;
+
+  // If we got messages before the route was added (due to race conditions
+  // between different channels), this is used to buffer them.
+  struct PendingMessage {
+    PendingMessage();
+    ~PendingMessage();
+    std::vector<char> message;
+    ScopedPlatformHandleVectorPtr handles;
+  };
+  std::vector<scoped_ptr<PendingMessage>> pending_messages_;
+
+  // If we got a ROUTE_CLOSED message for a route before it registered with us,
+  // we need to hold on to this information so that we can tell it that the
+  // connetion is closed when it does connect.
+  base::hash_set<uint64_t> close_routes_;
+
+  base::Callback<void(RoutedRawChannel*)> destruct_callback_;
+
+  DISALLOW_COPY_AND_ASSIGN(RoutedRawChannel);
+};
+
+}  // namespace edk
+}  // namespace mojo
+
+#endif  // MOJO_EDK_SYSTEM_ROUTED_RAW_CHANNEL_H_