diff -r 000000000000 -r 6474c204b198 gfx/skia/trunk/src/core/SkTObjectPool.h --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/gfx/skia/trunk/src/core/SkTObjectPool.h Wed Dec 31 06:09:35 2014 +0100 @@ -0,0 +1,104 @@ +/* + * Copyright 2014 Google Inc. + * + * Use of this source code is governed by a BSD-style license that can be + * found in the LICENSE file. + */ + +#ifndef SkFreeList_DEFINED +#define SkFreeList_DEFINED + +#include "SkTInternalSList.h" + +/** + * An implementation of a self growing pool of objects. + * It maintains a pool of fully initialized objects. If an attempt is made to + * acquire one, and there are none left, it makes some more. + * It does not automatically reclaim them, they have to be given back to it. + * Constructors will be called on objects allocated by the pool at allocation + * time. + * All allocated objects will be destroyed and memory will be reclaimed when + * the pool is destroyed, so the pool must survive longer than you are using + * any item taken from it. + */ +template class SkTObjectPool { +public: + SkTObjectPool() {} + ~SkTObjectPool() { + while (!fBlocks.isEmpty()) { + SkDELETE(fBlocks.pop()); + } + } + + /** + * Get an item from the pool. + * If the pool has no free items, it will allocate and construct some more. + * The returned item is only valid as long as the pool has not been + * destroyed, at that point all memory allocated by grow will have been + * reclaimed. + * This method is *not* thread safe. + */ + T* acquire() { + if (fAvailable.isEmpty()) { + grow(); + } + return fAvailable.pop(); + } + + /** + * Release an item into the pool. + * The item does not have to have come from the pool, but if it did not + * it must have a lifetime greater than the pool does. + * This method is *not* thread safe. + */ + void release(T* entry) { + fAvailable.push(entry); + } + + /** + * Takes all the items from an SkTInternalSList and adds them back to this + * pool. The other list will be left empty. + */ + void releaseAll(SkTInternalSList* other) { + fAvailable.pushAll(other); + } + + /** + * Returns the number of items immediately available without having to + * construct any new ones. + */ + int available() const { return fAvailable.getCount(); } + + /** + * Returns the number of blocks of items the pool has allocated so far. + */ + int blocks() const { return fBlocks.getCount(); } + +private: + /** + * The type for a new block of entries for the list. + */ + struct Block { + T entries[numItemsPerBlock]; + SK_DECLARE_INTERNAL_SLIST_INTERFACE(Block); + }; + SkTInternalSList fBlocks; + SkTInternalSList fAvailable; + + /** + * When the free list runs out of items, this method is called to allocate + * a new block of them. + * It calls the constructors and then pushes the nodes into the available + * list. + */ + void grow() { + Block* block = SkNEW(Block); + fBlocks.push(block); + for(int index = 0; index < numItemsPerBlock; ++index) { + fAvailable.push(&block->entries[index]); + } + } + +}; + +#endif