kc3-lang/angle/src/libANGLE/signal_utils.h

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• Hash : 1e5499db
  Author :
  Date : 2017-04-05T11:22:16
  

  Refactor Signal utils into template classes.
  
  This will allow us to pass on extra information to the receiving end,
  such as the specific texture levels that are dirty.
  
  BUG=angleproject:1635
  
  Change-Id: Idb7ca1d625499e50e7712c458b694f6e9bfc0595
  Reviewed-on: https://chromium-review.googlesource.com/453382
  Commit-Queue: Jamie Madill <jmadill@chromium.org>
  Reviewed-by: Geoff Lang <geofflang@chromium.org>
  

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• src/libANGLE/signal_utils.h

• //
  // 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"
  #include "common/debug.h"
  
  namespace angle
  {
  
  // Interface that the depending class inherits from.
  template <typename ChannelID = uint32_t, typename... MessageT>
  class SignalReceiver
  {
    public:
      virtual ~SignalReceiver() = default;
      virtual void signal(ChannelID channelID, MessageT... message) = 0;
  };
  
  template <typename ChannelID, typename... MessageT>
  class ChannelBinding;
  
  // The host class owns the channel. It uses the channel to fire signals to the receiver.
  template <typename ChannelID = uint32_t, typename... MessageT>
  class BroadcastChannel final : NonCopyable
  {
    public:
      BroadcastChannel();
      ~BroadcastChannel();
  
      void signal(MessageT... message) const;
  
      void reset();
  
    private:
      // Only the ChannelBinding class should add or remove receivers.
      friend class ChannelBinding<ChannelID, MessageT...>;
      void addReceiver(ChannelBinding<ChannelID, MessageT...> *receiver);
      void removeReceiver(ChannelBinding<ChannelID, MessageT...> *receiver);
  
      std::vector<ChannelBinding<ChannelID, MessageT...> *> mReceivers;
  };
  
  template <typename ChannelID, typename... MessageT>
  BroadcastChannel<ChannelID, MessageT...>::BroadcastChannel()
  {
  }
  
  template <typename ChannelID, typename... MessageT>
  BroadcastChannel<ChannelID, MessageT...>::~BroadcastChannel()
  {
      reset();
  }
  
  template <typename ChannelID, typename... MessageT>
  void BroadcastChannel<ChannelID, MessageT...>::addReceiver(
      ChannelBinding<ChannelID, MessageT...> *receiver)
  {
      ASSERT(std::find(mReceivers.begin(), mReceivers.end(), receiver) == mReceivers.end());
      mReceivers.push_back(receiver);
  }
  
  template <typename ChannelID, typename... MessageT>
  void BroadcastChannel<ChannelID, MessageT...>::removeReceiver(
      ChannelBinding<ChannelID, MessageT...> *receiver)
  {
      auto iter = std::find(mReceivers.begin(), mReceivers.end(), receiver);
      ASSERT(iter != mReceivers.end());
      mReceivers.erase(iter);
  }
  
  template <typename ChannelID, typename... MessageT>
  void BroadcastChannel<ChannelID, MessageT...>::signal(MessageT... message) const
  {
      if (mReceivers.empty())
          return;
  
      for (const auto *receiver : mReceivers)
      {
          receiver->signal(message...);
      }
  }
  
  template <typename ChannelID, typename... MessageT>
  void BroadcastChannel<ChannelID, MessageT...>::reset()
  {
      for (auto receiver : mReceivers)
      {
          receiver->onChannelClosed();
      }
      mReceivers.clear();
  }
  
  // The dependent class keeps bindings to the host's BroadcastChannel.
  template <typename ChannelID = uint32_t, typename... MessageT>
  class ChannelBinding final
  {
    public:
      ChannelBinding(SignalReceiver<ChannelID, MessageT...> *receiver, ChannelID channelID);
      ~ChannelBinding();
      ChannelBinding(const ChannelBinding &other) = default;
      ChannelBinding &operator=(const ChannelBinding &other) = default;
  
      void bind(BroadcastChannel<ChannelID, MessageT...> *channel);
      void reset();
      void signal(MessageT... message) const;
      void onChannelClosed();
  
    private:
      BroadcastChannel<ChannelID, MessageT...> *mChannel;
      SignalReceiver<ChannelID, MessageT...> *mReceiver;
      ChannelID mChannelID;
  };
  
  template <typename ChannelID, typename... MessageT>
  ChannelBinding<ChannelID, MessageT...>::ChannelBinding(
      SignalReceiver<ChannelID, MessageT...> *receiver,
      ChannelID channelID)
      : mChannel(nullptr), mReceiver(receiver), mChannelID(channelID)
  {
      ASSERT(receiver);
  }
  
  template <typename ChannelID, typename... MessageT>
  ChannelBinding<ChannelID, MessageT...>::~ChannelBinding()
  {
      reset();
  }
  
  template <typename ChannelID, typename... MessageT>
  void ChannelBinding<ChannelID, MessageT...>::bind(BroadcastChannel<ChannelID, MessageT...> *channel)
  {
      ASSERT(mReceiver);
      if (mChannel)
      {
          mChannel->removeReceiver(this);
      }
  
      mChannel = channel;
  
      if (mChannel)
      {
          mChannel->addReceiver(this);
      }
  }
  
  template <typename ChannelID, typename... MessageT>
  void ChannelBinding<ChannelID, MessageT...>::reset()
  {
      bind(nullptr);
  }
  
  template <typename ChannelID, typename... MessageT>
  void ChannelBinding<ChannelID, MessageT...>::signal(MessageT... message) const
  {
      mReceiver->signal(mChannelID, message...);
  }
  
  template <typename ChannelID, typename... MessageT>
  void ChannelBinding<ChannelID, MessageT...>::onChannelClosed()
  {
      mChannel = nullptr;
  }
  
  }  // namespace angle
  
  #endif  // LIBANGLE_SIGNAL_UTILS_H_
  

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