| /* |
| * Copyright 2012 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #ifndef GrMemoryPool_DEFINED |
| #define GrMemoryPool_DEFINED |
| |
| #include "src/base/SkBlockAllocator.h" |
| |
| #include <cstddef> |
| #include <cstdint> |
| #include <memory> |
| #include <type_traits> |
| |
| #ifdef SK_DEBUG |
| #include "src/core/SkTHash.h" |
| #endif |
| |
| /** |
| * Allocates memory in blocks and parcels out space in the blocks for allocation requests. It is |
| * optimized for allocate / release speed over memory efficiency. The interface is designed to be |
| * used to implement operator new and delete overrides. All allocations are expected to be released |
| * before the pool's destructor is called. Allocations will be aligned to sizeof(std::max_align_t). |
| * |
| * All allocated objects must be released back to the memory pool before it can be destroyed. |
| */ |
| class GrMemoryPool { |
| public: |
| #ifdef SK_FORCE_8_BYTE_ALIGNMENT |
| // https://github.com/emscripten-core/emscripten/issues/10072 |
| // Since Skia does not use "long double" (16 bytes), we should be ok to force it back to 8 bytes |
| // until emscripten is fixed. |
| inline static constexpr size_t kAlignment = 8; |
| #else |
| // Guaranteed alignment of pointer returned by allocate(). |
| inline static constexpr size_t kAlignment = alignof(std::max_align_t); |
| #endif |
| |
| // Smallest block size allocated on the heap (not the smallest reservation via allocate()). |
| inline static constexpr size_t kMinAllocationSize = 1 << 10; |
| |
| /** |
| * Prealloc size is the amount of space to allocate at pool creation |
| * time and keep around until pool destruction. The min alloc size is |
| * the smallest allowed size of additional allocations. Both sizes are |
| * adjusted to ensure that they are at least as large as kMinAllocationSize |
| * and less than SkBlockAllocator::kMaxAllocationSize. |
| * |
| * Both sizes are what the pool will end up allocating from the system, and |
| * portions of the allocated memory is used for internal bookkeeping. |
| */ |
| static std::unique_ptr<GrMemoryPool> Make(size_t preallocSize, size_t minAllocSize); |
| |
| ~GrMemoryPool(); |
| void operator delete(void* p) { ::operator delete(p); } |
| |
| /** |
| * Allocates memory. The memory must be freed with release() before the GrMemoryPool is deleted. |
| */ |
| void* allocate(size_t size); |
| /** |
| * p must have been returned by allocate(). |
| */ |
| void release(void* p); |
| |
| /** |
| * Returns true if there are no unreleased allocations. |
| */ |
| bool isEmpty() const { |
| // If size is the same as preallocSize, there aren't any heap blocks, so currentBlock() |
| // is the inline head block. |
| return fAllocator.currentBlock() == fAllocator.headBlock() && |
| fAllocator.currentBlock()->metadata() == 0; |
| } |
| |
| /** |
| * In debug mode, this reports the IDs of unfreed nodes via `SkDebugf`. This reporting is also |
| * performed automatically whenever a GrMemoryPool is destroyed. |
| * In release mode, this method is a no-op. |
| */ |
| void reportLeaks() const; |
| |
| /** |
| * Returns the total allocated size of the GrMemoryPool minus any preallocated amount |
| */ |
| size_t size() const { return fAllocator.totalSize() - fAllocator.preallocSize(); } |
| |
| /** |
| * Returns the preallocated size of the GrMemoryPool |
| */ |
| size_t preallocSize() const { |
| // Account for the debug-only fields in this count, the offset is 0 for release builds |
| static_assert(std::is_standard_layout<GrMemoryPool>::value, ""); |
| return offsetof(GrMemoryPool, fAllocator) + fAllocator.preallocSize(); |
| } |
| |
| /** |
| * Frees any scratch blocks that are no longer being used. |
| */ |
| void resetScratchSpace() { |
| fAllocator.resetScratchSpace(); |
| } |
| |
| #ifdef SK_DEBUG |
| void validate() const; |
| #endif |
| |
| private: |
| // Per-allocation overhead so that GrMemoryPool can always identify the block owning each and |
| // release all occupied bytes, including any resulting from alignment padding. |
| struct Header { |
| int fStart; |
| int fEnd; |
| #if defined(SK_DEBUG) |
| int fID; // ID that can be used to track down leaks by clients. |
| #endif |
| #if defined(SK_DEBUG) || defined(SK_SANITIZE_ADDRESS) |
| uint32_t fSentinel; // set to a known value to check for memory stomping; poisoned in ASAN mode |
| #endif |
| }; |
| |
| GrMemoryPool(size_t preallocSize, size_t minAllocSize); |
| |
| #ifdef SK_DEBUG |
| // Because this exists preallocSize wants to use offsetof, so keep GrMemoryPool standard layout |
| // without depending on SkTHashSet being standard layout. Note that std::unique_ptr may not be |
| // standard layout. |
| struct Debug{ |
| SkTHashSet<int> fAllocatedIDs; |
| int fAllocationCount; |
| }; |
| Debug* fDebug{nullptr}; |
| #endif |
| |
| SkBlockAllocator fAllocator; // Must be the last field, in order to use extra allocated space |
| }; |
| #endif |