mojo/system/waiter_list.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_SYSTEM_WAITER_LIST_H_
#define MOJO_SYSTEM_WAITER_LIST_H_

#include <stdint.h>

#include <list>

#include "base/macros.h"
#include "mojo/public/c/system/types.h"
#include "mojo/system/system_impl_export.h"

namespace mojo {
namespace system {

class Waiter;
struct HandleSignalsState;

// |WaiterList| tracks all the |Waiter|s that are waiting on a given
// handle/|Dispatcher|. There should be a |WaiterList| for each handle that can
// be waited on (in any way). In the simple case, the |WaiterList| is owned by
// the |Dispatcher|, whereas in more complex cases it is owned by the secondary
// object (see simple_dispatcher.* and the explanatory comment in core.cc). This
// class is thread-unsafe (all concurrent access must be protected by some
// lock).
class MOJO_SYSTEM_IMPL_EXPORT WaiterList {
 public:
  WaiterList();
  ~WaiterList();

  void AwakeWaitersForStateChange(const HandleSignalsState& state);
  void CancelAllWaiters();
  void AddWaiter(Waiter* waiter, MojoHandleSignals signals, uint32_t context);
  void RemoveWaiter(Waiter* waiter);

 private:
  struct WaiterInfo {
    WaiterInfo(Waiter* waiter, MojoHandleSignals signals, uint32_t context)
        : waiter(waiter), signals(signals), context(context) {}

    Waiter* waiter;
    MojoHandleSignals signals;
    uint32_t context;
  };
  typedef std::list<WaiterInfo> WaiterInfoList;

  WaiterInfoList waiters_;

  DISALLOW_COPY_AND_ASSIGN(WaiterList);
};

}  // namespace system
}  // namespace mojo

#endif  // MOJO_SYSTEM_WAITER_LIST_H_