Support custom message filtering on Mojo binding objects

mojo/public/cpp/bindings/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_INTERFACE_ENDPOINT_CLIENT_H_
 #define MOJO_PUBLIC_CPP_BINDINGS_INTERFACE_ENDPOINT_CLIENT_H_
 
 #include <stdint.h>
 
 #include <map>
 #include <memory>
 
 #include "base/callback.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "base/single_thread_task_runner.h"
 #include "base/threading/thread_checker.h"
+#include "mojo/public/cpp/bindings/filter_chain.h"
 #include "mojo/public/cpp/bindings/message.h"
-#include "mojo/public/cpp/bindings/message_filter.h"
 #include "mojo/public/cpp/bindings/scoped_interface_endpoint_handle.h"
 
 namespace mojo {
 
 class AssociatedGroup;
 class AssociatedGroupController;
 class InterfaceEndpointController;
 
 // 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,
-                          std::unique_ptr<MessageFilter> payload_validator,
+                          std::unique_ptr<MessageReceiver> payload_validator,
                           bool expect_sync_requests,
                           scoped_refptr<base::SingleThreadTaskRunner> runner);
   ~InterfaceEndpointClient() override;
 
   // Sets the error handler to receive notifications when an error is
   // encountered.
   void set_connection_error_handler(const base::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 !async_responders_.empty() || !sync_responses_.empty();
   }
 
   AssociatedGroupController* group_controller() const {
     return handle_.group_controller();
   }
   AssociatedGroup* associated_group();
   uint32_t interface_id() const;
 
+  // Adds a MessageReceiver which can filter a message after validation but
+  // before dispatch.
+  void AddFilter(std::unique_ptr<MessageReceiver> filter);
+
   // 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,
@@ skipping 44 matching lines @@
     DISALLOW_COPY_AND_ASSIGN(HandleIncomingMessageThunk);
   };
 
   bool HandleValidatedMessage(Message* message);
 
   ScopedInterfaceEndpointHandle handle_;
   std::unique_ptr<AssociatedGroup> associated_group_;
   InterfaceEndpointController* controller_;
 
   MessageReceiverWithResponderStatus* const incoming_receiver_;
-  std::unique_ptr<MessageFilter> payload_validator_;
   HandleIncomingMessageThunk thunk_;
+  FilterChain filters_;
 
   AsyncResponderMap async_responders_;
   SyncResponseMap sync_responses_;
 
   uint64_t next_request_id_;
 
   base::Closure error_handler_;
   bool encountered_error_;
 
   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
 
   base::ThreadChecker thread_checker_;
 
   base::WeakPtrFactory<InterfaceEndpointClient> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(InterfaceEndpointClient);
 };
 
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_INTERFACE_ENDPOINT_CLIENT_H_