kc3-lang/angle/src/common/MemoryBuffer.cpp

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• Hash : 25390156
  Author :
  Date : 2025-08-21T00:13:19
  

  Suppress unsafe buffers on a file-by-file basis in src/ [1 of N]
  
  In this CL, we suppress many files but stop short of actually
  enabling the warning by not removing the line from the
  unsafe_buffers_paths.txt file. That will happen in a follow-on
  CL, along with resolving any stragglers missed here.
  
  This is mostly a manual change so as to familiarize myself with
  the kinds of issues faced by the Angle codebase when applying buffer
  safety warnings.
  
  -- Re-generate affected hashes.
  -- Clang-format applied to all changed files.
  -- Add a few missing .reserve() calls to vectors as noticed.
  -- Fix some mismatches between file names and header comments.
  -- Be more consistent with header comment format (blank lines and
     trailing //-only lines when a filename comment adjoins license
     boilerplate).
  
  Bug: b/436880895
  Change-Id: I3bde5cc2059acbe8345057289214f1a26f1c34aa
  Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/6869022
  Reviewed-by: Geoff Lang <geofflang@chromium.org>
  Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
  Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>
  

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• src/common/MemoryBuffer.cpp

• //
  // Copyright 2014 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.
  //
  
  #ifdef UNSAFE_BUFFERS_BUILD
  #    pragma allow_unsafe_buffers
  #endif
  
  #include "common/MemoryBuffer.h"
  
  #include <algorithm>
  #include <cstdlib>
  #include <cstring>
  
  #include "common/debug.h"
  
  namespace angle
  {
  
  // MemoryBuffer implementation.
  MemoryBuffer::~MemoryBuffer()
  {
      destroy();
  }
  
  void MemoryBuffer::destroy()
  {
      if (mData)
      {
          free(mData);
          mData = nullptr;
      }
  
      mSize     = 0;
      mCapacity = 0;
  #if defined(ANGLE_ENABLE_ASSERTS)
      mTotalAllocatedBytes = 0;
      mTotalCopiedBytes    = 0;
  #endif  // ANGLE_ENABLE_ASSERTS
  }
  
  bool MemoryBuffer::resize(size_t newSize)
  {
      // If new size is within mCapacity, update mSize and early-return
      if (newSize <= mCapacity)
      {
          mSize = newSize;
          return true;
      }
  
      // New size exceeds mCapacity, need to reallocate and copy over previous content.
      uint8_t *newMemory = static_cast<uint8_t *>(malloc(sizeof(uint8_t) * newSize));
      if (newMemory == nullptr)
      {
          return false;
      }
  
  // Book keeping
  #if defined(ANGLE_ENABLE_ASSERTS)
      mTotalAllocatedBytes += newSize;
  #endif  // ANGLE_ENABLE_ASSERTS
  
      if (mData)
      {
          if (mSize > 0)
          {
              // Copy the intersection of the old data and the new data
              std::copy(mData, mData + mSize, newMemory);
  
  // Book keeping
  #if defined(ANGLE_ENABLE_ASSERTS)
              mTotalCopiedBytes += mSize;
  #endif  // ANGLE_ENABLE_ASSERTS
          }
          free(mData);
      }
  
      mData     = newMemory;
      mSize     = newSize;
      mCapacity = newSize;
  
      return true;
  }
  
  bool MemoryBuffer::clearAndReserve(size_t newSize)
  {
      clear();
      return reserve(newSize);
  }
  
  bool MemoryBuffer::reserve(size_t newSize)
  {
      if (newSize <= mCapacity)
      {
          // Can already accommodate newSize, nothing to do.
          return true;
      }
  
      // Cache original size
      size_t originalSize = mSize;
  
      if (!resize(newSize))
      {
          return false;
      }
  
      // reserve(...) won't affect mSize, reset to original value.
      mSize = originalSize;
  
      return true;
  }
  
  bool MemoryBuffer::append(const MemoryBuffer &other)
  {
      uint8_t *srcBuffer         = other.mData;
      const size_t srcBufferSize = other.mSize;
  
      // Handle the corner case where we are appending to self
      if (this == &other)
      {
          if (!reserve(mSize * 2))
          {
              return false;
          }
          srcBuffer = other.mData;
      }
  
      return appendRaw(srcBuffer, srcBufferSize);
  }
  
  bool MemoryBuffer::appendRaw(const uint8_t *buffer, const size_t bufferSize)
  {
      ASSERT(buffer && bufferSize > 0);
  
      if (!reserve(mSize + bufferSize))
      {
          return false;
      }
  
      std::memcpy(mData + mSize, buffer, bufferSize);
      mSize += bufferSize;
  
      return true;
  }
  
  void MemoryBuffer::fill(uint8_t datum)
  {
      if (!empty())
      {
          std::fill(mData, mData + mSize, datum);
      }
  }
  
  MemoryBuffer::MemoryBuffer(MemoryBuffer &&other) : MemoryBuffer()
  {
      *this = std::move(other);
  }
  
  MemoryBuffer &MemoryBuffer::operator=(MemoryBuffer &&other)
  {
      std::swap(mSize, other.mSize);
      std::swap(mCapacity, other.mCapacity);
      std::swap(mData, other.mData);
      return *this;
  }
  
  namespace
  {
  static constexpr uint32_t kDefaultScratchBufferLifetime = 1000u;
  
  }  // anonymous namespace
  
  // ScratchBuffer implementation.
  ScratchBuffer::ScratchBuffer() : ScratchBuffer(kDefaultScratchBufferLifetime) {}
  
  ScratchBuffer::ScratchBuffer(uint32_t lifetime) : mLifetime(lifetime), mResetCounter(lifetime) {}
  
  ScratchBuffer::~ScratchBuffer() {}
  
  ScratchBuffer::ScratchBuffer(ScratchBuffer &&other)
  {
      *this = std::move(other);
  }
  
  ScratchBuffer &ScratchBuffer::operator=(ScratchBuffer &&other)
  {
      std::swap(mLifetime, other.mLifetime);
      std::swap(mResetCounter, other.mResetCounter);
      std::swap(mScratchMemory, other.mScratchMemory);
      return *this;
  }
  
  bool ScratchBuffer::get(size_t requestedSize, MemoryBuffer **memoryBufferOut)
  {
      return getImpl(requestedSize, memoryBufferOut, Optional<uint8_t>::Invalid());
  }
  
  bool ScratchBuffer::getInitialized(size_t requestedSize,
                                     MemoryBuffer **memoryBufferOut,
                                     uint8_t initValue)
  {
      return getImpl(requestedSize, memoryBufferOut, Optional<uint8_t>(initValue));
  }
  
  bool ScratchBuffer::getImpl(size_t requestedSize,
                              MemoryBuffer **memoryBufferOut,
                              Optional<uint8_t> initValue)
  {
      mScratchMemory.setSizeToCapacity();
  
      if (mScratchMemory.size() == requestedSize)
      {
          mResetCounter    = mLifetime;
          *memoryBufferOut = &mScratchMemory;
          return true;
      }
  
      if (mScratchMemory.size() > requestedSize)
      {
          tick();
      }
  
      if (mScratchMemory.size() < requestedSize)
      {
          if (!mScratchMemory.resize(requestedSize))
          {
              return false;
          }
          mResetCounter = mLifetime;
          if (initValue.valid())
          {
              mScratchMemory.fill(initValue.value());
          }
      }
  
      ASSERT(mScratchMemory.size() >= requestedSize);
  
      *memoryBufferOut = &mScratchMemory;
      return true;
  }
  
  void ScratchBuffer::tick()
  {
      if (mResetCounter > 0)
      {
          --mResetCounter;
          if (mResetCounter == 0)
          {
              clear();
          }
      }
  }
  
  void ScratchBuffer::clear()
  {
      mResetCounter = mLifetime;
      if (mScratchMemory.size() > 0)
      {
          mScratchMemory.clear();
      }
  }
  
  }  // namespace angle
  

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