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

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• Hash : cf9383ed
  Author :
  Date : 2019-01-31T19:52:49
  

  Optimize VertexArray::bindVertexBufferImpl.
  
  Reduces the buffer nullptr checks to a single location. Also optimizes
  how the transform feedback binding counter is changed.
  
  Improves the score of the draw call vertex array change test.
  
  Bug: angleproject:3014
  Change-Id: I08ff341e08194a407c24143965a3d568e92b97b7
  Reviewed-on: https://chromium-review.googlesource.com/c/1406891
  Commit-Queue: Jamie Madill <jmadill@chromium.org>
  Reviewed-by: Geoff Lang <geofflang@chromium.org>
  

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• src/libANGLE/Observer.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.
  //
  // 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/
  
  #ifndef LIBANGLE_OBSERVER_H_
  #define LIBANGLE_OBSERVER_H_
  
  #include "common/FastVector.h"
  #include "common/angleutils.h"
  
  namespace gl
  {
  class Context;
  }  // namespace gl
  
  namespace angle
  {
  template <typename HaystackT, typename NeedleT>
  bool IsInContainer(const HaystackT &haystack, const NeedleT &needle)
  {
      return std::find(haystack.begin(), haystack.end(), needle) != haystack.end();
  }
  
  using SubjectIndex = size_t;
  
  enum class SubjectMessage
  {
      CONTENTS_CHANGED,
      STORAGE_CHANGED,
      BINDING_CHANGED,
      DEPENDENT_DIRTY_BITS,
      RESOURCE_MAPPED,
      RESOURCE_UNMAPPED,
  };
  
  // The observing class inherits from this interface class.
  class ObserverInterface
  {
    public:
      virtual ~ObserverInterface();
      virtual void onSubjectStateChange(const gl::Context *context,
                                        SubjectIndex index,
                                        SubjectMessage message) = 0;
  };
  
  class ObserverBindingBase
  {
    public:
      ObserverBindingBase(ObserverInterface *observer, SubjectIndex subjectIndex)
          : mObserver(observer), mIndex(subjectIndex)
      {}
      virtual ~ObserverBindingBase() {}
  
      ObserverInterface *getObserver() const { return mObserver; }
      SubjectIndex getSubjectIndex() const { return mIndex; }
  
      virtual void onSubjectReset() {}
  
    private:
      ObserverInterface *mObserver;
      SubjectIndex mIndex;
  };
  
  // Maintains a list of observer bindings. Sends update messages to the observer.
  class Subject : NonCopyable
  {
    public:
      Subject();
      virtual ~Subject();
  
      void onStateChange(const gl::Context *context, SubjectMessage message) const;
      bool hasObservers() const;
      void resetObservers();
  
      ANGLE_INLINE void addObserver(ObserverBindingBase *observer)
      {
          ASSERT(!IsInContainer(mObservers, observer));
          mObservers.push_back(observer);
      }
  
      ANGLE_INLINE void removeObserver(ObserverBindingBase *observer)
      {
          ASSERT(IsInContainer(mObservers, observer));
          mObservers.remove_and_permute(observer);
      }
  
    private:
      // Keep a short list of observers so we can allocate/free them quickly. But since we support
      // unlimited bindings, have a spill-over list of that uses dynamic allocation.
      static constexpr size_t kMaxFixedObservers = 8;
      angle::FastVector<ObserverBindingBase *, kMaxFixedObservers> mObservers;
  };
  
  // Keeps a binding between a Subject and Observer, with a specific subject index.
  class ObserverBinding final : public ObserverBindingBase
  {
    public:
      ObserverBinding(ObserverInterface *observer, SubjectIndex index);
      ~ObserverBinding() override;
      ObserverBinding(const ObserverBinding &other);
      ObserverBinding &operator=(const ObserverBinding &other);
  
      void bind(Subject *subject);
  
      ANGLE_INLINE void reset() { bind(nullptr); }
  
      void onStateChange(const gl::Context *context, SubjectMessage message) const;
      void onSubjectReset() override;
  
      ANGLE_INLINE const Subject *getSubject() const { return mSubject; }
  
      ANGLE_INLINE void assignSubject(Subject *subject) { mSubject = subject; }
  
    private:
      Subject *mSubject;
  };
  
  }  // namespace angle
  
  #endif  // LIBANGLE_OBSERVER_H_
  

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