kc3-lang/angle/src/libANGLE/Observer.cpp

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• Hash : d511948b
  Author :
  Date : 2018-09-18T11:32:42
  

  Use FastVector in angle::Subject.
  
  This improves object binding performance. We no longer need to check
  two containers when manipulating the bound subjects/observers.
  
  Bug: angleproject:2763
  Change-Id: I0ccb2e76be47bd8a28fba5a0c3eff857aa166bb7
  Reviewed-on: https://chromium-review.googlesource.com/1227795
  Commit-Queue: Jamie Madill <jmadill@chromium.org>
  Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
  Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
  

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• src/libANGLE/Observer.cpp

• //
  // Copyright 2018 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.
  //
  // Observer:
  //   Implements the Observer pattern for sending state change notifications
  //   from Subject objects to dependent Observer objects.
  //
  //   See design document:
  //   https://docs.google.com/document/d/15Edfotqg6_l1skTEL8ADQudF_oIdNa7i8Po43k6jMd4/
  
  #include "libANGLE/Observer.h"
  
  #include <algorithm>
  
  #include "common/debug.h"
  
  namespace angle
  {
  namespace
  {
  template <typename HaystackT, typename NeedleT>
  bool IsInContainer(const HaystackT &haystack, const NeedleT &needle)
  {
      return std::find(haystack.begin(), haystack.end(), needle) != haystack.end();
  }
  }  // anonymous namespace
  
  // Observer implementation.
  ObserverInterface::~ObserverInterface() = default;
  
  // Subject implementation.
  Subject::Subject()
  {
  }
  
  Subject::~Subject()
  {
      resetObservers();
  }
  
  bool Subject::hasObservers() const
  {
      return !mObservers.empty();
  }
  
  ANGLE_INLINE void Subject::addObserver(ObserverBinding *observer)
  {
      ASSERT(!IsInContainer(mObservers, observer));
      mObservers.push_back(observer);
  }
  
  ANGLE_INLINE void Subject::removeObserver(ObserverBinding *observer)
  {
      ASSERT(IsInContainer(mObservers, observer));
      size_t len = mObservers.size() - 1;
      for (size_t index = 0; index < len; ++index)
      {
          if (mObservers[index] == observer)
          {
              mObservers[index] = mObservers[len];
              break;
          }
      }
      mObservers.pop_back();
  }
  
  void Subject::onStateChange(const gl::Context *context, SubjectMessage message) const
  {
      if (mObservers.empty())
          return;
  
      for (const angle::ObserverBinding *receiver : mObservers)
      {
          receiver->onStateChange(context, message);
      }
  }
  
  void Subject::resetObservers()
  {
      for (angle::ObserverBinding *observer : mObservers)
      {
          observer->onSubjectReset();
      }
      mObservers.clear();
  }
  
  // ObserverBinding implementation.
  ObserverBinding::ObserverBinding(ObserverInterface *observer, SubjectIndex index)
      : mSubject(nullptr), mObserver(observer), mIndex(index)
  {
      ASSERT(observer);
  }
  
  ObserverBinding::~ObserverBinding()
  {
      reset();
  }
  
  ObserverBinding::ObserverBinding(const ObserverBinding &other) = default;
  
  ObserverBinding &ObserverBinding::operator=(const ObserverBinding &other) = default;
  
  void ObserverBinding::bind(Subject *subject)
  {
      ASSERT(mObserver);
      if (mSubject)
      {
          mSubject->removeObserver(this);
      }
  
      mSubject = subject;
  
      if (mSubject)
      {
          mSubject->addObserver(this);
      }
  }
  
  void ObserverBinding::reset()
  {
      bind(nullptr);
  }
  
  void ObserverBinding::onStateChange(const gl::Context *context, SubjectMessage message) const
  {
      mObserver->onSubjectStateChange(context, mIndex, message);
  }
  
  void ObserverBinding::onSubjectReset()
  {
      mSubject = nullptr;
  }
  
  const Subject *ObserverBinding::getSubject() const
  {
      return mSubject;
  }
  }  // namespace angle
  

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