src/v8/src/heap/array-buffer-collector.h

// Copyright 2017 the V8 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.

#ifndef V8_HEAP_ARRAY_BUFFER_COLLECTOR_H_
#define V8_HEAP_ARRAY_BUFFER_COLLECTOR_H_

#include <vector>

#include "src/base/platform/mutex.h"
#include "src/objects/js-array-buffer.h"

namespace v8 {
namespace internal {

class Heap;

// To support background processing of array buffer backing stores, we process
// array buffers using the ArrayBufferTracker class. The ArrayBufferCollector
// keeps track of garbage backing stores so that they can be freed on a
// background thread.
class ArrayBufferCollector {
 public:
  explicit ArrayBufferCollector(Heap* heap) : heap_(heap) {}

  ~ArrayBufferCollector() { PerformFreeAllocations(); }

  // These allocations will be either
  // - freed immediately when under memory pressure, or
  // - queued for freeing in FreeAllocations() or during tear down.
  //
  // FreeAllocations() potentially triggers a background task for processing.
  void QueueOrFreeGarbageAllocations(
      std::vector<JSArrayBuffer::Allocation> allocations);

  // Calls FreeAllocations() on a background thread.
  void FreeAllocations();

 private:
  class FreeingTask;

  // Begin freeing the allocations added through QueueOrFreeGarbageAllocations.
  // Also called by TearDown.
  void PerformFreeAllocations();

  Heap* const heap_;
  base::Mutex allocations_mutex_;
  std::vector<std::vector<JSArrayBuffer::Allocation>> allocations_;
};

}  // namespace internal
}  // namespace v8

#endif  // V8_HEAP_ARRAY_BUFFER_COLLECTOR_H_