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// 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_COMMON_HANDLE_WATCHER_H_
#define MOJO_COMMON_HANDLE_WATCHER_H_
#include "base/basictypes.h"
#include "base/callback_forward.h"
#include "base/memory/scoped_ptr.h"
#include "mojo/common/mojo_common_export.h"
#include "mojo/public/system/core.h"
namespace base {
class Thread;
class TickClock;
class TimeTicks;
}
namespace mojo {
namespace common {
namespace test {
class HandleWatcherTest;
}
// HandleWatcher is used to asynchronously wait on a handle and notify a Closure
// when the handle is ready, or the deadline has expired.
class MOJO_COMMON_EXPORT HandleWatcher {
public:
HandleWatcher();
~HandleWatcher();
// Starts listening for |handle|. This implicitly invokes Stop(). In other
// words, Start() performs one asynchronous watch at a time. It is ok to call
// Start() multiple times, but it cancels any existing watches. |callback| is
// notified when the handle is ready, invalid or deadline has passed and is
// notified on the thread Start() was invoked on.
void Start(MojoHandle handle,
MojoWaitFlags wait_flags,
MojoDeadline deadline,
const base::Callback<void(MojoResult)>& callback);
// Stops listening. Does nothing if not in the process of listening.
void Stop();
// Returns now. Used internally; generally not useful.
static base::TimeTicks NowTicks();
// Converts a MojoDeadline into a TimeTicks.
static base::TimeTicks MojoDeadlineToTimeTicks(MojoDeadline deadline);
private:
friend class test::HandleWatcherTest;
struct StartState;
// See description of |StartState::weak_factory| for details.
void OnHandleReady(MojoResult result);
// If non-NULL Start() has been invoked.
scoped_ptr<StartState> start_state_;
// Used for getting the time. Only set by tests.
static base::TickClock* tick_clock_;
DISALLOW_COPY_AND_ASSIGN(HandleWatcher);
};
} // namespace common
} // namespace mojo
#endif // MOJO_COMMON_HANDLE_WATCHER_H_