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

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• Author : Solti Ho
  Date : 2023-12-13 18:28:53
  Hash : df4d9667
  Message : Revert "Optimize HandleAllocator for fast ID churning." This reverts commit b25ffe5a9775cc912a304c8552dd9c097a93420a. Reason for revert: b/316162914 Original change's description: > Optimize HandleAllocator for fast ID churning. > > Instead of calculating ranges of IDs and the overhead with updating > them every allocation/release, store a released ID list in a small > FastVector. > > Optimize the allocate path for the "good case" of no reserved IDs so > that it either pops the last released ID or incriments a next value and > returns it. Release has a similar cost of just a push_back when there > are no reserved IDs. > > This adds a small fixed memory cost due to the FastVector and a dynamic > memory cost of mReleasedList having up to N elements where N is the > maxmimum total handles allocated at one time. > > Bug: angleproject:8434 > Change-Id: I7c5aa126b5303c105cd2464d0d0933b922cc2b8f > Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5101509 > Reviewed-by: Charlie Lao <cclao@google.com> > Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org> Bug: angleproject:8434 Change-Id: Ide43d787b6942cc6b622e3b5d938bfbbbf3b3ebb No-Presubmit: true No-Tree-Checks: true No-Try: true Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5120277 Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>

• src/libANGLE/HandleAllocator.h

• //
  // Copyright 2002 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.
  //
  
  // HandleAllocator.h: Defines the gl::HandleAllocator class, which is used to
  // allocate GL handles.
  
  #ifndef LIBANGLE_HANDLEALLOCATOR_H_
  #define LIBANGLE_HANDLEALLOCATOR_H_
  
  #include "common/angleutils.h"
  
  #include "angle_gl.h"
  
  namespace gl
  {
  
  class HandleAllocator final : angle::NonCopyable
  {
    public:
      // Maximum handle = MAX_UINT-1
      HandleAllocator();
      // Specify maximum handle value. Used for testing.
      HandleAllocator(GLuint maximumHandleValue);
  
      ~HandleAllocator();
  
      void setBaseHandle(GLuint value);
  
      GLuint allocate();
      void release(GLuint handle);
      void reserve(GLuint handle);
      void reset();
      bool anyHandleAvailableForAllocation() const;
  
      void enableLogging(bool enabled);
  
    private:
      GLuint mBaseValue;
      GLuint mNextValue;
      const GLuint mMaxValue;
  
      // Represents an inclusive range [begin, end]
      struct HandleRange
      {
          HandleRange(GLuint beginIn, GLuint endIn) : begin(beginIn), end(endIn) {}
  
          GLuint begin;
          GLuint end;
      };
  
      struct HandleRangeComparator;
  
      // The freelist consists of never-allocated handles, stored
      // as ranges, and handles that were previously allocated and
      // released, stored in a heap.
      std::vector<HandleRange> mUnallocatedList;
      std::vector<GLuint> mReleasedList;
  
      bool mLoggingEnabled;
  };
  
  }  // namespace gl
  
  #endif  // LIBANGLE_HANDLEALLOCATOR_H_