Mojo C++ bindings: introduce MultiplexRouter and related classes.

mojo/public/cpp/bindings/lib/interface_endpoint_client.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_PUBLIC_CPP_BINDINGS_LIB_INTERFACE_ENDPOINT_CLIENT_H_
+#define MOJO_PUBLIC_CPP_BINDINGS_LIB_INTERFACE_ENDPOINT_CLIENT_H_
+
+#include <map>
+
+#include "base/logging.h"
+#include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
+#include "base/threading/thread_checker.h"
+#include "mojo/public/cpp/bindings/callback.h"
+#include "mojo/public/cpp/bindings/lib/scoped_interface_endpoint_handle.h"
+#include "mojo/public/cpp/bindings/message.h"
+#include "mojo/public/cpp/bindings/message_filter.h"
+
+namespace mojo {
+namespace internal {
+
+// InterfaceEndpointClient handles message sending and receiving of an interface
+// endpoint, either the implementation side or the client side.
+// It should only be accessed and destructed on the creating thread.
+class InterfaceEndpointClient : public MessageReceiverWithResponder {
+ public:
+  // |receiver| is okay to be null. If it is not null, it must outlive this
+  // object.
+  InterfaceEndpointClient(ScopedInterfaceEndpointHandle handle,
+                          MessageReceiverWithResponderStatus* receiver,
+                          scoped_ptr<MessageFilter> payload_validator);
+  ~InterfaceEndpointClient() override;
+
+  // Sets the error handler to receive notifications when an error is
+  // encountered.
+  void set_connection_error_handler(const Closure& error_handler) {
+    DCHECK(thread_checker_.CalledOnValidThread());
+    error_handler_ = error_handler;
+  }
+
+  // Returns true if an error was encountered.
+  bool encountered_error() const {
+    DCHECK(thread_checker_.CalledOnValidThread());
+    return encountered_error_;
+  }
+
+  // Returns true if this endpoint has any pending callbacks.
+  bool has_pending_responders() const {
+    DCHECK(thread_checker_.CalledOnValidThread());
+    return !responders_.empty();
+  }
+
+  MultiplexRouter* router() const { return handle_.router(); }
+
+  // After this call the object is in an invalid state and shouldn't be reused.
+  ScopedInterfaceEndpointHandle PassHandle();
+
+  // Raises an error on the underlying message pipe. It disconnects the pipe
+  // and notifies all interfaces running on this pipe.
+  void RaiseError();
+
+  // MessageReceiverWithResponder implementation:
+  bool Accept(Message* message) override;
+  bool AcceptWithResponder(Message* message,
+                           MessageReceiver* responder) override;
+
+  // The following methods are called by the router. They must be called
+  // outside of the router's lock.
+
+  // NOTE: |message| must have passed message header validation.
+  bool HandleIncomingMessage(Message* message);
+  void NotifyError();
+
+ private:
+  using ResponderMap = std::map<uint64_t, MessageReceiver*>;
+
+  // Used as the sink for |payload_validator_| and forwards messages to
+  // HandleValidatedMessage().
+  class HandleIncomingMessageThunk : public MessageReceiver {
+   public:
+    explicit HandleIncomingMessageThunk(InterfaceEndpointClient* owner);
+    ~HandleIncomingMessageThunk() override;
+
+    // MessageReceiver implementation:
+    bool Accept(Message* message) override;
+
+   private:
+    InterfaceEndpointClient* const owner_;
+
+    DISALLOW_COPY_AND_ASSIGN(HandleIncomingMessageThunk);
+  };
+
+  bool HandleValidatedMessage(Message* message);
+
+  ScopedInterfaceEndpointHandle handle_;
+
+  MessageReceiverWithResponderStatus* const incoming_receiver_;
+  scoped_ptr<MessageFilter> payload_validator_;
+  HandleIncomingMessageThunk thunk_;
+
+  // Maps from the ID of a response to the MessageReceiver that handles the
+  // response.
+  ResponderMap responders_;
+  uint64_t next_request_id_;
+
+  Closure error_handler_;
+  bool encountered_error_;
+
+  base::ThreadChecker thread_checker_;
+
+  base::WeakPtrFactory<InterfaceEndpointClient> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(InterfaceEndpointClient);
+};
+
+}  // namespace internal
+}  // namespace mojo
+
+#endif  // MOJO_PUBLIC_CPP_BINDINGS_LIB_INTERFACE_ENDPOINT_CLIENT_H_