Mojo: Armed Watchers

mojo/public/cpp/bindings/connector.h

 // Copyright 2013 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_CONNECTOR_H_
 #define MOJO_PUBLIC_CPP_BINDINGS_CONNECTOR_H_
 
 #include <memory>
 
 #include "base/callback.h"
 #include "base/compiler_specific.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "base/optional.h"
 #include "base/single_thread_task_runner.h"
 #include "base/threading/thread_checker.h"
 #include "mojo/public/cpp/bindings/bindings_export.h"
 #include "mojo/public/cpp/bindings/message.h"
 #include "mojo/public/cpp/bindings/sync_handle_watcher.h"
 #include "mojo/public/cpp/system/core.h"
-#include "mojo/public/cpp/system/watcher.h"
+#include "mojo/public/cpp/system/simple_watcher.h"
 
 namespace base {
 class Lock;
 }
 
 namespace mojo {
 
 // The Connector class is responsible for performing read/write operations on a
 // MessagePipe. It writes messages it receives through the MessageReceiver
 // interface that it subclasses, and it forwards messages it reads through the
@@ skipping 116 matching lines @@
   }
 
   base::SingleThreadTaskRunner* task_runner() const {
     return task_runner_.get();
   }
 
   // Sets the tag used by the heap profiler.
   // |tag| must be a const string literal.
   void SetWatcherHeapProfilerTag(const char* tag);
 
+  // Enables support for nested message dispatch so that the Connector can
+  // continue dispatching inbound messages even if one of them spins a nested
+  // message loop. This should be enabled only when needed, as dispatch in this
+  // mode is generally less efficient.
+  void EnableNestedDispatch(bool enabled);
+
  private:
-  // Callback of mojo::Watcher.
+  // Callback of mojo::SimpleWatcher.
   void OnWatcherHandleReady(MojoResult result);
   // Callback of SyncHandleWatcher.
   void OnSyncHandleWatcherHandleReady(MojoResult result);
   void OnHandleReadyInternal(MojoResult result);
 
   void WaitToReadMore();
 
   // Returns false if it is impossible to receive more messages in the future.
   // |this| may have been destroyed in that case.
   WARN_UNUSED_RESULT bool ReadSingleMessage(MojoResult* read_result);
@@ skipping 11 matching lines @@
   void CancelWait();
 
   void EnsureSyncWatcherExists();
 
   base::Closure connection_error_handler_;
 
   ScopedMessagePipeHandle message_pipe_;
   MessageReceiver* incoming_receiver_ = nullptr;
 
   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
-  std::unique_ptr<Watcher> handle_watcher_;
+  std::unique_ptr<SimpleWatcher> handle_watcher_;
 
   bool error_ = false;
   bool drop_writes_ = false;
   bool enforce_errors_from_incoming_receiver_ = true;
 
   bool paused_ = false;
 
+  bool nested_dispatch_enabled_ = false;
+
   // If sending messages is allowed from multiple threads, |lock_| is used to
   // protect modifications to |message_pipe_| and |drop_writes_|.
   base::Optional<base::Lock> lock_;
 
   std::unique_ptr<SyncHandleWatcher> sync_watcher_;
   bool allow_woken_up_by_others_ = false;
   // If non-zero, currently the control flow is inside the sync handle watcher
   // callback.
   size_t sync_handle_watcher_callback_count_ = 0;
 
@@ skipping 12 matching lines @@
   // transferred (i.e., when |connected_| is set to false).
   base::WeakPtr<Connector> weak_self_;
   base::WeakPtrFactory<Connector> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(Connector);
 };
 
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_CONNECTOR_H_