chromium/third_party/skia/src/text/gpu/SubRunAllocator.h

/*
 * Copyright 2021 Google LLC
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#ifndef sktext_gpu_SubRunAllocator_DEFINED
#define sktext_gpu_SubRunAllocator_DEFINED

#include "include/core/SkSpan.h"
#include "include/private/base/SkAssert.h"
#include "include/private/base/SkMath.h"
#include "include/private/base/SkTLogic.h"
#include "include/private/base/SkTemplates.h"
#include "include/private/base/SkTo.h"
#include "src/base/SkArenaAlloc.h"

#include <algorithm>
#include <array>
#include <climits>
#include <cstddef>
#include <cstdint>
#include <cstring>
#include <limits>
#include <memory>
#include <new>
#include <tuple>
#include <utility>

namespace sktext::gpu {

// BagOfBytes parcels out bytes with a given size and alignment.
class BagOfBytes { … };

template <typename T>
class SubRunInitializer { … };

// GrSubRunAllocator provides fast allocation where the user takes care of calling the destructors
// of the returned pointers, and GrSubRunAllocator takes care of deleting the storage. The
// unique_ptrs returned, are to assist in assuring the object's destructor is called.
// A note on zero length arrays: according to the standard a pointer must be returned, and it
// can't be a nullptr. In such a case, SkArena allocates one byte, but does not initialize it.
class SubRunAllocator { … };

// Helper for defining allocators with inline/reserved storage.
// For argument declarations, stick to the base type (SubRunAllocator).
// Note: Inheriting from the storage first means the storage will outlive the
// SubRunAllocator, letting ~SubRunAllocator read it as it calls destructors.
// (This is mostly only relevant for strict tools like MSAN.)
template <size_t InlineStorageSize, size_t InlineStorageAlignment>
class STSubRunAllocator : private std::array<char,
                                             BagOfBytes::PlatformMinimumSizeWithOverhead(
                                                     InlineStorageSize, InlineStorageAlignment)>,
                          public SubRunAllocator { … };
}  // namespace sktext::gpu

#endif // sktext_gpu_SubRunAllocator_DEFINED