Add a Mojo EDK for Chrome that uses one OS pipe per message pipe.

mojo/edk/system/message_pipe_dispatcher.h

-// Copyright 2013 The Chromium Authors. All rights reserved.
+// 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_MESSAGE_PIPE_DISPATCHER_H_
 #define MOJO_EDK_SYSTEM_MESSAGE_PIPE_DISPATCHER_H_
 
 #include "base/memory/ref_counted.h"
+#include "mojo/edk/embedder/platform_channel_pair.h"
+#include "mojo/edk/system/awakable_list.h"
 #include "mojo/edk/system/dispatcher.h"
 #include "mojo/edk/system/memory.h"
+#include "mojo/edk/system/raw_channel.h"
 #include "mojo/edk/system/system_impl_export.h"
 #include "mojo/public/cpp/system/macros.h"
 
 namespace mojo {
-namespace system {
-
-class ChannelEndpoint;
-class MessagePipe;
-class MessagePipeDispatcherTransport;
+namespace edk {
 
 // This is the |Dispatcher| implementation for message pipes (created by the
 // Mojo primitive |MojoCreateMessagePipe()|). This class is thread-safe.
-class MOJO_SYSTEM_IMPL_EXPORT MessagePipeDispatcher final : public Dispatcher {
+class MOJO_SYSTEM_IMPL_EXPORT MessagePipeDispatcher final
+    : public Dispatcher, public RawChannel::Delegate {
  public:
   // The default options to use for |MojoCreateMessagePipe()|. (Real uses
   // should obtain this via |ValidateCreateOptions()| with a null |in_options|;
   // this is exposed directly for testing convenience.)
   static const MojoCreateMessagePipeOptions kDefaultCreateOptions;
 
   static scoped_refptr<MessagePipeDispatcher> Create(
       const MojoCreateMessagePipeOptions& /*validated_options*/) {
     return make_scoped_refptr(new MessagePipeDispatcher());
   }
 
   // Validates and/or sets default options for |MojoCreateMessagePipeOptions|.
   // If non-null, |in_options| must point to a struct of at least
   // |in_options->struct_size| bytes. |out_options| must point to a (current)
   // |MojoCreateMessagePipeOptions| and will be entirely overwritten on success
   // (it may be partly overwritten on failure).
   static MojoResult ValidateCreateOptions(
       UserPointer<const MojoCreateMessagePipeOptions> in_options,
       MojoCreateMessagePipeOptions* out_options);
 
   // Must be called before any other methods. (This method is not thread-safe.)
-  void Init(scoped_refptr<MessagePipe> message_pipe,
-            unsigned port) MOJO_NOT_THREAD_SAFE;
+  void Init(ScopedPlatformHandle message_pipe);
 
   // |Dispatcher| public methods:
   Type GetType() const override;
 
-  // Creates a |MessagePipe| with a local endpoint (at port 0) and a proxy
-  // endpoint, and creates/initializes a |MessagePipeDispatcher| (attached to
-  // the message pipe, port 0).
-  // TODO(vtl): This currently uses |kDefaultCreateOptions|, which is okay since
-  // there aren't any options, but eventually options should be plumbed through.
-  static scoped_refptr<MessagePipeDispatcher> CreateRemoteMessagePipe(
-      scoped_refptr<ChannelEndpoint>* channel_endpoint);
-
   // The "opposite" of |SerializeAndClose()|. (Typically this is called by
   // |Dispatcher::Deserialize()|.)
-  static scoped_refptr<MessagePipeDispatcher> Deserialize(Channel* channel,
-                                                          const void* source,
-                                                          size_t size);
+  static scoped_refptr<MessagePipeDispatcher> Deserialize(
+      const void* source,
+      size_t size,
+      PlatformHandleVector* platform_handles);
 
  private:
-  friend class MessagePipeDispatcherTransport;
-
   MessagePipeDispatcher();
   ~MessagePipeDispatcher() override;
 
-  // Gets a dumb pointer to |message_pipe_|. This must be called under the
-  // |Dispatcher| lock (that it's a dumb pointer is okay since it's under lock).
-  // This is needed when sending handles across processes, where nontrivial,
-  // invasive work needs to be done.
-  MessagePipe* GetMessagePipeNoLock() const;
-  // Similarly for the port.
-  unsigned GetPortNoLock() const;
+  void InitWithReadBuffer(ScopedPlatformHandle message_pipe,
+                          char* data,
+                          size_t size);
+
+  void InitOnIO();
+  void CloseOnIO();
 
   // |Dispatcher| protected methods:
   void CancelAllAwakablesNoLock() override;
   void CloseImplNoLock() override;
   scoped_refptr<Dispatcher> CreateEquivalentDispatcherAndCloseImplNoLock()
       override;
   MojoResult WriteMessageImplNoLock(
       UserPointer<const void> bytes,
       uint32_t num_bytes,
       std::vector<DispatcherTransport>* transports,
       MojoWriteMessageFlags flags) override;
   MojoResult ReadMessageImplNoLock(UserPointer<void> bytes,
                                    UserPointer<uint32_t> num_bytes,
                                    DispatcherVector* dispatchers,
                                    uint32_t* num_dispatchers,
                                    MojoReadMessageFlags flags) override;
   HandleSignalsState GetHandleSignalsStateImplNoLock() const override;
   MojoResult AddAwakableImplNoLock(Awakable* awakable,
                                    MojoHandleSignals signals,
                                    uint32_t context,
                                    HandleSignalsState* signals_state) override;
   void RemoveAwakableImplNoLock(Awakable* awakable,
                                 HandleSignalsState* signals_state) override;
-  void StartSerializeImplNoLock(Channel* channel,
-                                size_t* max_size,
-                                size_t* max_platform_handles) override
-      MOJO_NOT_THREAD_SAFE;
+  void StartSerializeImplNoLock(size_t* max_size,
+                                size_t* max_platform_handles) override;
   bool EndSerializeAndCloseImplNoLock(
-      Channel* channel,
       void* destination,
       size_t* actual_size,
-      embedder::PlatformHandleVector* platform_handles) override
-      MOJO_NOT_THREAD_SAFE;
+      PlatformHandleVector* platform_handles) override;
+  void TransportStarted() override;
+  void TransportEnded() override;
 
-  // This will be null if closed.
-  scoped_refptr<MessagePipe> message_pipe_ MOJO_GUARDED_BY(mutex());
-  unsigned port_ MOJO_GUARDED_BY(mutex());
+  // |RawChannel::Delegate methods:
+  void OnReadMessage(
+    const MessageInTransit::View& message_view,
+    ScopedPlatformHandleVectorPtr platform_handles) override;
+  void OnError(Error error) override;
+
+  // Calls ReleaseHandle and serializes the raw channel. This is split into a
+  // function because it's called in two different ways:
+  // 1) When serializing "live" dispatchers that are passed to MojoWriteMessage,
+  // CreateEquivalentDispatcherAndCloseImplNoLock calls this.
+  // 2) When serializing dispatchers that are attached to deserialized messages
+  // which haven't been consumed by MojoReadMessage, StartSerializeImplNoLock
+  // calls this.
+  void SerializeInternal();
+
+  MojoResult AttachTransportsNoLock(
+      MessageInTransit* message,
+      std::vector<DispatcherTransport>* transports);
+
+  // Protected by |lock()|:
+  RawChannel* channel_;
+
+  // Queue of incoming messages that we read from RawChannel but haven't been
+  // consumed through MojoReadMessage yet.
+  MessageInTransitQueue message_queue_;
+  // When sending MP, contains serialized message_queue_.
+  bool serialized_;
+  std::vector<char> serialized_message_queue_;
+  std::vector<char> serialized_read_buffer_;
+  PlatformHandle serialized_platform_handle_;
+  // TODO(jam): stop using this and use shared memory instead since we are
+  // limited to 10K here.
+  AwakableList awakable_list_;
+
+  // if DispatcherTransport crated. must be set before lock() is called to avoid
+  // deadlocks with RawChannel calling us.
+  base::Lock started_transport_;
+
+  bool calling_init_;
+  bool error_;
 
   MOJO_DISALLOW_COPY_AND_ASSIGN(MessagePipeDispatcher);
 };
 
-class MessagePipeDispatcherTransport : public DispatcherTransport {
- public:
-  explicit MessagePipeDispatcherTransport(DispatcherTransport transport);
-
-  MessagePipe* GetMessagePipe() {
-    return message_pipe_dispatcher()->GetMessagePipeNoLock();
-  }
-  unsigned GetPort() { return message_pipe_dispatcher()->GetPortNoLock(); }
-
- private:
-  MessagePipeDispatcher* message_pipe_dispatcher() {
-    return static_cast<MessagePipeDispatcher*>(dispatcher());
-  }
-
-  // Copy and assign allowed.
-};
-
-}  // namespace system
+}  // namespace edk
 }  // namespace mojo
 
 #endif  // MOJO_EDK_SYSTEM_MESSAGE_PIPE_DISPATCHER_H_