Move more Mojo bindings helpers out of internal namespace

mojo/public/cpp/bindings/lib/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_LIB_CONNECTOR_H_
-#define MOJO_PUBLIC_CPP_BINDINGS_LIB_CONNECTOR_H_
-
-#include <memory>
-
-#include "base/callback.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/lib/sync_handle_watcher.h"
-#include "mojo/public/cpp/bindings/message.h"
-#include "mojo/public/cpp/system/core.h"
-#include "mojo/public/cpp/system/watcher.h"
-
-namespace base {
-class Lock;
-}
-
-namespace mojo {
-namespace internal {
-
-// 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
-// MessageReceiver interface assigned as its incoming receiver.
-//
-// NOTE:
-//   - MessagePipe I/O is non-blocking.
-//   - Sending messages can be configured to be thread safe (please see comments
-//     of the constructor). Other than that, the object should only be accessed
-//     on the creating thread.
-class Connector : public MessageReceiver {
- public:
-  enum ConnectorConfig {
-    // Connector::Accept() is only called from a single thread.
-    SINGLE_THREADED_SEND,
-    // Connector::Accept() is allowed to be called from multiple threads.
-    MULTI_THREADED_SEND
-  };
-
-  // The Connector takes ownership of |message_pipe|.
-  Connector(ScopedMessagePipeHandle message_pipe,
-            ConnectorConfig config,
-            scoped_refptr<base::SingleThreadTaskRunner> runner);
-  ~Connector() override;
-
-  // Sets the receiver to handle messages read from the message pipe.  The
-  // Connector will read messages from the pipe regardless of whether or not an
-  // incoming receiver has been set.
-  void set_incoming_receiver(MessageReceiver* receiver) {
-    DCHECK(thread_checker_.CalledOnValidThread());
-    incoming_receiver_ = receiver;
-  }
-
-  // Errors from incoming receivers will force the connector into an error
-  // state, where no more messages will be processed. This method is used
-  // during testing to prevent that from happening.
-  void set_enforce_errors_from_incoming_receiver(bool enforce) {
-    DCHECK(thread_checker_.CalledOnValidThread());
-    enforce_errors_from_incoming_receiver_ = enforce;
-  }
-
-  // Sets the error handler to receive notifications when an error is
-  // encountered while reading from the pipe or waiting to read from the pipe.
-  void set_connection_error_handler(const base::Closure& error_handler) {
-    DCHECK(thread_checker_.CalledOnValidThread());
-    connection_error_handler_ = error_handler;
-  }
-
-  // Returns true if an error was encountered while reading from the pipe or
-  // waiting to read from the pipe.
-  bool encountered_error() const {
-    DCHECK(thread_checker_.CalledOnValidThread());
-    return error_;
-  }
-
-  // Closes the pipe. The connector is put into a quiescent state.
-  //
-  // Please note that this method shouldn't be called unless it results from an
-  // explicit request of the user of bindings (e.g., the user sets an
-  // InterfacePtr to null or closes a Binding).
-  void CloseMessagePipe();
-
-  // Releases the pipe. Connector is put into a quiescent state.
-  ScopedMessagePipeHandle PassMessagePipe();
-
-  // Enters the error state. The upper layer may do this for unrecoverable
-  // issues such as invalid messages are received. If a connection error handler
-  // has been set, it will be called asynchronously.
-  //
-  // It is a no-op if the connector is already in the error state or there isn't
-  // a bound message pipe. Otherwise, it closes the message pipe, which notifies
-  // the other end and also prevents potential danger (say, the caller raises
-  // an error because it believes the other end is malicious). In order to
-  // appear to the user that the connector still binds to a message pipe, it
-  // creates a new message pipe, closes one end and binds to the other.
-  void RaiseError();
-
-  // Is the connector bound to a MessagePipe handle?
-  bool is_valid() const {
-    DCHECK(thread_checker_.CalledOnValidThread());
-    return message_pipe_.is_valid();
-  }
-
-  // Waits for the next message on the pipe, blocking until one arrives,
-  // |deadline| elapses, or an error happens. Returns |true| if a message has
-  // been delivered, |false| otherwise.
-  bool WaitForIncomingMessage(MojoDeadline deadline);
-
-  // See Binding for details of pause/resume.
-  void PauseIncomingMethodCallProcessing();
-  void ResumeIncomingMethodCallProcessing();
-
-  // MessageReceiver implementation:
-  bool Accept(Message* message) override;
-
-  MessagePipeHandle handle() const {
-    DCHECK(thread_checker_.CalledOnValidThread());
-    return message_pipe_.get();
-  }
-
-  // Allows |message_pipe_| to be watched while others perform sync handle
-  // watching on the same thread. Please see comments of
-  // SyncHandleWatcher::AllowWokenUpBySyncWatchOnSameThread().
-  void AllowWokenUpBySyncWatchOnSameThread();
-
-  // Watches |message_pipe_| (as well as other handles registered to be watched
-  // together) synchronously.
-  // This method:
-  //   - returns true when |should_stop| is set to true;
-  //   - return false when any error occurs, including |message_pipe_| being
-  //     closed.
-  bool SyncWatch(const bool* should_stop);
-
-  // Whether currently the control flow is inside the sync handle watcher
-  // callback.
-  bool during_sync_handle_watcher_callback() const {
-    return sync_handle_watcher_callback_count_ > 0;
-  }
-
-  base::SingleThreadTaskRunner* task_runner() const {
-    return task_runner_.get();
-  }
-
- private:
-  // Callback of mojo::Watcher.
-  void OnWatcherHandleReady(MojoResult result);
-  // Callback of SyncHandleWatcher.
-  void OnSyncHandleWatcherHandleReady(MojoResult result);
-  void OnHandleReadyInternal(MojoResult result);
-
-  void WaitToReadMore();
-
-  // Returns false if |this| was destroyed during message dispatch.
-  WARN_UNUSED_RESULT bool ReadSingleMessage(MojoResult* read_result);
-
-  // |this| can be destroyed during message dispatch.
-  void ReadAllAvailableMessages();
-
-  // If |force_pipe_reset| is true, this method replaces the existing
-  // |message_pipe_| with a dummy message pipe handle (whose peer is closed).
-  // If |force_async_handler| is true, |connection_error_handler_| is called
-  // asynchronously.
-  void HandleError(bool force_pipe_reset, bool force_async_handler);
-
-  // Cancels any calls made to |waiter_|.
-  void CancelWait();
-
-  void EnsureSyncWatcherExists();
-
-  base::Closure connection_error_handler_;
-
-  ScopedMessagePipeHandle message_pipe_;
-  MessageReceiver* incoming_receiver_;
-
-  scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
-  Watcher handle_watcher_;
-
-  bool error_;
-  bool drop_writes_;
-  bool enforce_errors_from_incoming_receiver_;
-
-  bool paused_;
-
-  // If sending messages is allowed from multiple threads, |lock_| is used to
-  // protect modifications to |message_pipe_| and |drop_writes_|.
-  std::unique_ptr<base::Lock> lock_;
-
-  std::unique_ptr<SyncHandleWatcher> sync_watcher_;
-  bool allow_woken_up_by_others_;
-  // If non-zero, currently the control flow is inside the sync handle watcher
-  // callback.
-  size_t sync_handle_watcher_callback_count_;
-
-  base::ThreadChecker thread_checker_;
-
-  // Create a single weak ptr and use it everywhere, to avoid the malloc/free
-  // cost of creating a new weak ptr whenever it is needed.
-  base::WeakPtr<Connector> weak_self_;
-  base::WeakPtrFactory<Connector> weak_factory_;
-
-  DISALLOW_COPY_AND_ASSIGN(Connector);
-};
-
-}  // namespace internal
-}  // namespace mojo
-
-#endif  // MOJO_PUBLIC_CPP_BINDINGS_LIB_CONNECTOR_H_