| /* |
| * Copyright 2013 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #ifndef SkImageCache_DEFINED |
| #define SkImageCache_DEFINED |
| |
| #include "SkRefCnt.h" |
| #include "SkTypes.h" |
| |
| /** |
| * Interface for a cache that manages pixel memory. |
| */ |
| class SkImageCache : public SkRefCnt { |
| |
| public: |
| /** |
| * Allocate memory whose lifetime is managed by the cache. On success, MUST be balanced with a |
| * call to releaseCache and a call to throwAwayCache. |
| * @param bytes Number of bytes needed. |
| * @param ID Output parameter which must not be NULL. On success, ID will be set to a value |
| * associated with that memory which can be used as a parameter to the other functions |
| * in SkImageCache. On failure, ID is unchanged. |
| * @return Pointer to the newly allocated memory, or NULL. This memory is safe to use until |
| * releaseCache is called with ID. |
| */ |
| virtual void* allocAndPinCache(size_t bytes, intptr_t* ID) = 0; |
| |
| /** |
| * Re-request the memory associated with ID. |
| * @param ID Unique ID for the memory block. |
| * @return Pointer: If non-NULL, points to the previously allocated memory, in which case |
| * this call must be balanced with a call to releaseCache. If NULL, the memory |
| * has been reclaimed, so allocAndPinCache must be called again, and ID is no |
| * longer valid (thus throwAwayCache need not be called). |
| */ |
| virtual void* pinCache(intptr_t ID) = 0; |
| |
| /** |
| * Inform the cache that it is safe to free the block of memory corresponding to ID. After |
| * calling this function, the pointer returnted by allocAndPinCache or pinCache must not be |
| * used again. In order to access the same memory after this, pinCache must be called. |
| * @param ID Unique ID for the memory block which is now safe to age out of the cache. |
| */ |
| virtual void releaseCache(intptr_t ID) = 0; |
| |
| /** |
| * Inform the cache that the block of memory associated with ID will not be asked for again. |
| * After this call, ID is no longer valid. Must not be called while the associated memory is |
| * pinned. Must be called to balance a successful allocAndPinCache, unless a later pinCache |
| * returns NULL. |
| */ |
| virtual void throwAwayCache(intptr_t ID) = 0; |
| |
| /** |
| * ID which does not correspond to any valid cache. |
| */ |
| static const intptr_t UNINITIALIZED_ID = 0; |
| |
| #ifdef SK_DEBUG |
| enum CacheStatus { |
| kPinned_CacheStatus, |
| kUnpinned_CacheStatus, |
| kThrownAway_CacheStatus, |
| }; |
| |
| /** |
| * Debug only function to get the status of a particular block of memory. |
| */ |
| virtual CacheStatus getCacheStatus(intptr_t ID) const = 0; |
| #endif |
| }; |
| #endif // SkImageCache_DEFINED |