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// Copyright 2019 The Chromium 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 THIRD_PARTY_BLINK_RENDERER_MODULES_WEBSOCKETS_WEBSOCKET_MESSAGE_CHUNK_ACCUMULATOR_H_
#define THIRD_PARTY_BLINK_RENDERER_MODULES_WEBSOCKETS_WEBSOCKET_MESSAGE_CHUNK_ACCUMULATOR_H_
#include <memory>
#include "base/containers/span.h"
#include "base/memory/scoped_refptr.h"
#include "base/time/time.h"
#include "third_party/blink/renderer/modules/modules_export.h"
#include "third_party/blink/renderer/platform/timer.h"
#include "third_party/blink/renderer/platform/wtf/allocator/allocator.h"
#include "third_party/blink/renderer/platform/wtf/vector.h"
#include "third_party/blink/renderer/platform/wtf/wtf_size_t.h"
namespace blink {
class SingleThreadTaskRunner;
// WebSocketMessageChunkAccumulator stores chunks for one WebSocket message. A
// user can call Append() to append bytes, and call GetView() to get a list of
// base::spans of data previously stored.
// We don't use SharedBuffer due to an observed performance problem of FastFree.
// TODO(yhirano): Remove this once the performance problem is fixed in a general
// manner.
class MODULES_EXPORT WebSocketMessageChunkAccumulator final {
DISALLOW_NEW();
public:
explicit WebSocketMessageChunkAccumulator(
scoped_refptr<base::SingleThreadTaskRunner> task_runner);
~WebSocketMessageChunkAccumulator();
// Appends |data| to this instance.
void Append(base::span<const char> data);
// Returns the number of bytes stored in this instance.
size_t GetSize() const { return size_; }
// Clears the stored data. Memory regions for chunks may be kept for future
// uses for certain amount of time.
void Clear();
// The regions will be available until Clear() is called.
Vector<base::span<const char>> GetView() const;
wtf_size_t GetPoolSizeForTesting() const { return pool_.size(); }
bool IsTimerActiveForTesting() const { return timer_.IsActive(); }
static constexpr size_t kSegmentSize = 16 * 1024;
static constexpr base::TimeDelta kFreeDelay =
base::TimeDelta::FromMilliseconds(100);
private:
struct SegmentDeleter {
void operator()(char* p) const { WTF::Partitions::FastFree(p); }
};
using SegmentPtr = std::unique_ptr<char[], SegmentDeleter>;
static SegmentPtr CreateSegment() {
return SegmentPtr(static_cast<char*>(WTF::Partitions::FastMalloc(
kSegmentSize, "blink::WebSocketMessageChunkAccumulator::Segment")));
}
void OnTimerFired(TimerBase*);
size_t GetLastSegmentSize() const {
DCHECK(!segments_.IsEmpty());
return size_ % kSegmentSize > 0 ? size_ % kSegmentSize : kSegmentSize;
}
Vector<SegmentPtr> segments_;
Vector<SegmentPtr> pool_;
size_t size_ = 0;
wtf_size_t num_pooled_segments_to_be_removed_ = 0;
TaskRunnerTimer<WebSocketMessageChunkAccumulator> timer_;
};
} // namespace blink
#endif // THIRD_PARTY_BLINK_RENDERER_MODULES_WEBSOCKETS_WEBSOCKET_MESSAGE_CHUNK_ACCUMULATOR_H_