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// Copyright 2020 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef COMPONENTS_VIZ_COMMON_SURFACES_SUBTREE_CAPTURE_ID_ALLOCATOR_H_
#define COMPONENTS_VIZ_COMMON_SURFACES_SUBTREE_CAPTURE_ID_ALLOCATOR_H_
#include <cstdint>
#include "base/sequence_checker.h"
#include "components/viz/common/surfaces/subtree_capture_id.h"
namespace viz {
// Generates `SubtreeCaptureId`s by incrementally increasing the
// `next_subtree_id_`. This method of ID allocation is used for
// aura::Window capture, where IDs need to be process-unique due to the
// potential for Ash layers to move between FrameSinkIds. All IDs allocated by
// this method have zero as the `high` value.
class VIZ_COMMON_EXPORT SubtreeCaptureIdAllocator {
public:
SubtreeCaptureIdAllocator() = default;
SubtreeCaptureIdAllocator(const SubtreeCaptureIdAllocator&) = delete;
SubtreeCaptureIdAllocator& operator=(const SubtreeCaptureIdAllocator&) =
delete;
~SubtreeCaptureIdAllocator() {
DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
}
SubtreeCaptureId NextSubtreeCaptureId() {
DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
return SubtreeCaptureId(base::Token(0u, next_subtree_id_++));
}
private:
uint64_t next_subtree_id_ GUARDED_BY_CONTEXT(sequence_checker_) = 1u;
SEQUENCE_CHECKER(sequence_checker_);
};
} // namespace viz
#endif // COMPONENTS_VIZ_COMMON_SURFACES_SUBTREE_CAPTURE_ID_ALLOCATOR_H_
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