chromium/mojo/public/cpp/system/wait_set.h

// Copyright 2017 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef MOJO_PUBLIC_CPP_SYSTEM_WAIT_SET_H_
#define MOJO_PUBLIC_CPP_SYSTEM_WAIT_SET_H_

#include <stddef.h>
#include <stdint.h>

#include "base/memory/scoped_refptr.h"
#include "mojo/public/c/system/trap.h"
#include "mojo/public/c/system/types.h"
#include "mojo/public/cpp/system/handle.h"
#include "mojo/public/cpp/system/system_export.h"

namespace base {
class WaitableEvent;
}

namespace mojo {

// WaitSet provides an efficient means of blocking a sequence on any number of
// events and Mojo handle state changes.
//
// Unlike WaitMany(), which incurs some extra setup cost for every call, a
// WaitSet maintains some persistent accounting of the handles added or removed
// from the set. A blocking wait operation (see  the Wait() method  below) can
// then be performed multiple times for the same set of events and handles with
// minimal additional setup per call.
//
// WaitSet is NOT thread-safe, so naturally handles and events may not be added
// to or removed from the set while waiting.
class MOJO_CPP_SYSTEM_EXPORT WaitSet { … };

}  // namespace mojo

#endif  // MOJO_PUBLIC_CPP_SYSTEM_WAIT_SET_H_