text: /*
   * Copyright (C) 2017-2018 Apple Inc. All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
   * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
   * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
   * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
   * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
   * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
   * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
   * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
   */
  
  #pragma once
  
  #include "BlockDirectoryInlines.h"
  #include "HeapCellType.h"
  #include "JSCast.h"
  #include "MarkedBlock.h"
  #include "MarkedSpace.h"
  #include "Subspace.h"
  
  namespace JSC {
  
  template<typename Func>
  void Subspace::forEachDirectory(const Func& func)
  {
      for (BlockDirectory* directory = m_firstDirectory; directory; directory = directory->nextDirectoryInSubspace())
          func(*directory);
  }
  
  template<typename Func>
  void Subspace::forEachMarkedBlock(const Func& func)
  {
      forEachDirectory(
          [&] (BlockDirectory& directory) {
              directory.forEachBlock(func);
          });
  }
  
  template<typename Func>
  void Subspace::forEachNotEmptyMarkedBlock(const Func& func)
  {
      forEachDirectory(
          [&] (BlockDirectory& directory) {
              directory.forEachNotEmptyBlock(func);
          });
  }
  
  template<typename Func>
  void Subspace::forEachPreciseAllocation(const Func& func)
  {
      for (PreciseAllocation* allocation = m_preciseAllocations.begin(); allocation != m_preciseAllocations.end(); allocation = allocation->next())
          func(allocation);
  }
  
  template<typename Func>
  void Subspace::forEachMarkedCell(const Func& func)
  {
      forEachNotEmptyMarkedBlock(
          [&] (MarkedBlock::Handle* handle) {
              handle->forEachMarkedCell(
                  [&] (size_t, HeapCell* cell, HeapCell::Kind kind) -> IterationStatus {
                      func(cell, kind);
                      return IterationStatus::Continue;
                  });
          });
      CellAttributes attributes = this->attributes();
      forEachPreciseAllocation(
          [&] (PreciseAllocation* allocation) {
              if (allocation->isMarked())
                  func(allocation->cell(), attributes.cellKind);
          });
  }
  
  template<typename Func>
  Ref<SharedTask<void(SlotVisitor&)>> Subspace::forEachMarkedCellInParallel(const Func& func)
  {
      class Task final : public SharedTask<void(SlotVisitor&)> {
      public:
          Task(Subspace& subspace, const Func& func)
              : m_subspace(subspace)
              , m_blockSource(subspace.parallelNotEmptyMarkedBlockSource())
              , m_func(func)
          {
          }
          
          void run(SlotVisitor& visitor) final
          {
              while (MarkedBlock::Handle* handle = m_blockSource->run()) {
                  handle->forEachMarkedCell(
                      [&] (size_t, HeapCell* cell, HeapCell::Kind kind) -> IterationStatus {
                          m_func(visitor, cell, kind);
                          return IterationStatus::Continue;
                      });
              }
              
              {
                  auto locker = holdLock(m_lock);
                  if (!m_needToVisitPreciseAllocations)
                      return;
                  m_needToVisitPreciseAllocations = false;
              }
              
              CellAttributes attributes = m_subspace.attributes();
              m_subspace.forEachPreciseAllocation(
                  [&] (PreciseAllocation* allocation) {
                      if (allocation->isMarked())
                          m_func(visitor, allocation->cell(), attributes.cellKind);
                  });
          }
          
      private:
          Subspace& m_subspace;
          Ref<SharedTask<MarkedBlock::Handle*()>> m_blockSource;
          Func m_func;
          Lock m_lock;
          bool m_needToVisitPreciseAllocations { true };
      };
      
      return adoptRef(*new Task(*this, func));
  }
  
  template<typename Func>
  void Subspace::forEachLiveCell(const Func& func)
  {
      forEachMarkedBlock(
          [&] (MarkedBlock::Handle* handle) {
              handle->forEachLiveCell(
                  [&] (size_t, HeapCell* cell, HeapCell::Kind kind) -> IterationStatus {
                      func(cell, kind);
                      return IterationStatus::Continue;
                  });
          });
      CellAttributes attributes = this->attributes();
      forEachPreciseAllocation(
          [&] (PreciseAllocation* allocation) {
              if (allocation->isLive())
                  func(allocation->cell(), attributes.cellKind);
          });
  }
  
  inline const CellAttributes& Subspace::attributes() const
  {
      return m_heapCellType->attributes();
  }
  
  } // namespace JSC
  
  