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//
// Copyright 2016 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//
// signal_utils:
// Helper classes for tracking dependent state changes between objects.
// These changes are signaled to the dependent class via channels.
#ifndef LIBANGLE_SIGNAL_UTILS_H_
#define LIBANGLE_SIGNAL_UTILS_H_
#include <set>
#include "common/angleutils.h"
namespace angle
{
// Message token passed to the receiver;
using SignalToken = uint32_t;
// Interface that the depending class inherits from.
class SignalReceiver
{
public:
virtual ~SignalReceiver() = default;
virtual void signal(SignalToken token) = 0;
};
class ChannelBinding;
// The host class owns the channel. It uses the channel to fire signals to the receiver.
class BroadcastChannel final : NonCopyable
{
public:
BroadcastChannel();
~BroadcastChannel();
void signal() const;
void reset();
private:
// Only the ChannelBinding class should add or remove receivers.
friend class ChannelBinding;
void addReceiver(ChannelBinding *receiver);
void removeReceiver(ChannelBinding *receiver);
std::vector<ChannelBinding *> mReceivers;
};
// The dependent class keeps bindings to the host's BroadcastChannel.
class ChannelBinding final
{
public:
ChannelBinding(SignalReceiver *receiver, SignalToken token);
~ChannelBinding();
ChannelBinding(const ChannelBinding &other) = default;
ChannelBinding &operator=(const ChannelBinding &other) = default;
void bind(BroadcastChannel *channel);
void reset();
void signal() const;
void onChannelClosed();
private:
BroadcastChannel *mChannel;
SignalReceiver *mReceiver;
SignalToken mToken;
};
} // namespace angle
#endif // LIBANGLE_SIGNAL_UTILS_H_
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