Mojo: introducing a thread safe interface pointer.

mojo/public/cpp/bindings/lib/interface_ptr_state.h

 // Copyright 2014 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_PTR_STATE_H_
 #define MOJO_PUBLIC_CPP_BINDINGS_LIB_INTERFACE_PTR_STATE_H_
 
 #include <stdint.h>
 
 #include <algorithm>  // For |std::swap()|.
 #include <memory>
 #include <string>
 #include <utility>
 
 #include "base/bind.h"
 #include "base/callback_forward.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "base/memory/ref_counted.h"
+#include "base/memory/weak_ptr.h"
 #include "base/single_thread_task_runner.h"
 #include "mojo/public/cpp/bindings/associated_group.h"
 #include "mojo/public/cpp/bindings/connection_error_callback.h"
 #include "mojo/public/cpp/bindings/filter_chain.h"
 #include "mojo/public/cpp/bindings/interface_endpoint_client.h"
 #include "mojo/public/cpp/bindings/interface_id.h"
 #include "mojo/public/cpp/bindings/interface_ptr_info.h"
 #include "mojo/public/cpp/bindings/lib/control_message_handler.h"
 #include "mojo/public/cpp/bindings/lib/control_message_proxy.h"
 #include "mojo/public/cpp/bindings/lib/multiplex_router.h"
 #include "mojo/public/cpp/bindings/lib/router.h"
 #include "mojo/public/cpp/bindings/message_header_validator.h"
 #include "mojo/public/cpp/bindings/scoped_interface_endpoint_handle.h"
+#include "mojo/public/cpp/bindings/thread_safe_interface_ptr.h"
 
 namespace mojo {
 namespace internal {
 
 template <typename Interface, bool use_multiplex_router>
 class InterfacePtrState;
 
 // Uses a single-threaded, dedicated router. If |Interface| doesn't have any
 // methods to pass associated interface pointers or requests, there won't be
 // multiple interfaces running on the underlying message pipe. In that case, we
@@ skipping 158 matching lines @@
   uint32_t version_;
 
   DISALLOW_COPY_AND_ASSIGN(InterfacePtrState);
 };
 
 // Uses a multiplexing router. If |Interface| has methods to pass associated
 // interface pointers or requests, this specialization should be used.
 template <typename Interface>
 class InterfacePtrState<Interface, true> {
  public:
-  InterfacePtrState() : version_(0u) {}
+  InterfacePtrState() : version_(0u), weak_ptr_factory_(this) {}
 
   ~InterfacePtrState() {
     endpoint_client_.reset();
     proxy_.reset();
     if (router_)
       router_->CloseMessagePipe();
   }
 
   Interface* instance() {
     ConfigureProxyIfNecessary();
@@ skipping 101 matching lines @@
   AssociatedGroup* associated_group() {
     ConfigureProxyIfNecessary();
     return endpoint_client_->associated_group();
   }
 
   void EnableTestingMode() {
     ConfigureProxyIfNecessary();
     router_->EnableTestingMode();
   }
 
+  scoped_refptr<ThreadSafeInterfacePtr<Interface>> GetThreadSafePtr() {

[yzshen1, 2016/11/11 22:32:10]

One thing that seems a little weird about this is that the
ThreadSafeInterfacePtr is tied to the InterfacePtrState object itself, which is
not moved around like its contents. As a result, when an InterfacePtr x is moved
to y, although it behaves exactly the same, its connection with the
ThreadSafeInterfacePtr has gone.

[Jay Civelli, 2016/11/15 05:02:30]

Per our discussion, the  ThreadSafeInterfacePtr class is still thread safe ref
counted, but it now owns the InterfacePtr.

+    ConfigureProxyIfNecessary();
+    return new ThreadSafeInterfacePtr<Interface>(
+                     base::ThreadTaskRunnerHandle::Get(),
+                     base::Bind(&InterfacePtrState::ForwardMessage,
+                                weak_ptr_factory_.GetWeakPtr()),
+                     base::Bind(&InterfacePtrState::ForwardMessageWithResponder,
+                                weak_ptr_factory_.GetWeakPtr()));
+  }
+
  private:
   using Proxy = typename Interface::Proxy_;
 
   void ConfigureProxyIfNecessary() {
     // The proxy has been configured.
     if (proxy_) {
       DCHECK(router_);
       DCHECK(endpoint_client_);
       return;
     }
@@ skipping 20 matching lines @@
     proxy_->serialization_context()->group_controller =
         endpoint_client_->group_controller();
   }
 
   void OnQueryVersion(const base::Callback<void(uint32_t)>& callback,
                       uint32_t version) {
     version_ = version;
     callback.Run(version);
   }
 
+  void ForwardMessage(Message message) {
+    endpoint_client_->Accept(&message);
+  }
+
+  void ForwardMessageWithResponder(Message message,
+                                   std::unique_ptr<MessageReceiver> responder) {
+    endpoint_client_->AcceptWithResponder(&message, responder.release());
+  }
+
   scoped_refptr<MultiplexRouter> router_;
 
   std::unique_ptr<InterfaceEndpointClient> endpoint_client_;
   std::unique_ptr<Proxy> proxy_;
 
   // |router_| (as well as other members above) is not initialized until
   // read/write with the message pipe handle is needed. |handle_| is valid
   // between the Bind() call and the initialization of |router_|.
   ScopedMessagePipeHandle handle_;
   scoped_refptr<base::SingleThreadTaskRunner> runner_;
 
   uint32_t version_;
 
+  base::WeakPtrFactory<InterfacePtrState> weak_ptr_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(InterfacePtrState);
 };
 
 }  // namespace internal
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_LIB_INTERFACE_PTR_STATE_H_