| |
| /* |
| * 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 SkBitmapHeap_DEFINED |
| #define SkBitmapHeap_DEFINED |
| |
| #include "SkBitmap.h" |
| #include "SkFlattenable.h" |
| #include "SkRefCnt.h" |
| #include "SkTDArray.h" |
| #include "SkThread.h" |
| #include "SkTRefArray.h" |
| |
| /** |
| * SkBitmapHeapEntry provides users of SkBitmapHeap (using internal storage) with a means to... |
| * (1) get access a bitmap in the heap |
| * (2) indicate they are done with bitmap by releasing their reference (if they were an owner). |
| */ |
| class SkBitmapHeapEntry : SkNoncopyable { |
| public: |
| ~SkBitmapHeapEntry(); |
| |
| int32_t getSlot() { return fSlot; } |
| |
| SkBitmap* getBitmap() { return &fBitmap; } |
| |
| void releaseRef() { |
| sk_atomic_dec(&fRefCount); |
| } |
| |
| private: |
| SkBitmapHeapEntry(); |
| |
| void addReferences(int count); |
| |
| int32_t fSlot; |
| int32_t fRefCount; |
| |
| SkBitmap fBitmap; |
| // Keep track of the bytes allocated for this bitmap. When replacing the |
| // bitmap or removing this HeapEntry we know how much memory has been |
| // reclaimed. |
| size_t fBytesAllocated; |
| |
| friend class SkBitmapHeap; |
| friend class SkBitmapHeapTester; |
| }; |
| |
| |
| class SkBitmapHeapReader : public SkRefCnt { |
| public: |
| SK_DECLARE_INST_COUNT(SkBitmapHeapReader) |
| |
| SkBitmapHeapReader() : INHERITED() {} |
| virtual SkBitmap* getBitmap(int32_t slot) const = 0; |
| virtual void releaseRef(int32_t slot) = 0; |
| private: |
| typedef SkRefCnt INHERITED; |
| }; |
| |
| |
| /** |
| * TODO: stores immutable bitmaps into a heap |
| */ |
| class SkBitmapHeap : public SkBitmapHeapReader { |
| public: |
| class ExternalStorage : public SkRefCnt { |
| public: |
| SK_DECLARE_INST_COUNT(ExternalStorage) |
| |
| virtual bool insert(const SkBitmap& bitmap, int32_t slot) = 0; |
| |
| private: |
| typedef SkRefCnt INHERITED; |
| }; |
| |
| static const int32_t UNLIMITED_SIZE = -1; |
| static const int32_t IGNORE_OWNERS = -1; |
| static const int32_t INVALID_SLOT = -1; |
| |
| /** |
| * Constructs a heap that is responsible for allocating and managing its own storage. In the |
| * case where we choose to allow the heap to grow indefinitely (i.e. UNLIMITED_SIZE) we |
| * guarantee that once allocated in the heap a bitmap's index in the heap is immutable. |
| * Otherwise we guarantee the bitmaps placement in the heap until its owner count goes to zero. |
| * |
| * @param preferredSize Specifies the preferred maximum number of bitmaps to store. This is |
| * not a hard limit as it can grow larger if the number of bitmaps in the heap with active |
| * owners exceeds this limit. |
| * @param ownerCount The number of owners to assign to each inserted bitmap. NOTE: while a |
| * bitmap in the heap has a least one owner it can't be removed. |
| */ |
| SkBitmapHeap(int32_t preferredSize = UNLIMITED_SIZE, int32_t ownerCount = IGNORE_OWNERS); |
| |
| /** |
| * Constructs a heap that defers the responsibility of storing the bitmaps to an external |
| * function. This is especially useful if the bitmaps will be used in a separate process as the |
| * external storage can ensure the data is properly shuttled to the appropriate processes. |
| * |
| * Our LRU implementation assumes that inserts into the external storage are consumed in the |
| * order that they are inserted (i.e. SkPipe). This ensures that we don't need to query the |
| * external storage to see if a slot in the heap is eligible to be overwritten. |
| * |
| * @param externalStorage The class responsible for storing the bitmaps inserted into the heap |
| * @param heapSize The maximum size of the heap. Because of the sequential limitation imposed |
| * by our LRU implementation we can guarantee that the heap will never grow beyond this size. |
| */ |
| SkBitmapHeap(ExternalStorage* externalStorage, int32_t heapSize = UNLIMITED_SIZE); |
| |
| ~SkBitmapHeap(); |
| |
| /** |
| * Makes a shallow copy of all bitmaps currently in the heap and returns them as an array. The |
| * array indices match their position in the heap. |
| * |
| * @return a ptr to an array of bitmaps or NULL if external storage is being used. |
| */ |
| SkTRefArray<SkBitmap>* extractBitmaps() const; |
| |
| /** |
| * Retrieves the bitmap from the specified slot in the heap |
| * |
| * @return The bitmap located at that slot or NULL if external storage is being used. |
| */ |
| virtual SkBitmap* getBitmap(int32_t slot) const SK_OVERRIDE { |
| SkASSERT(fExternalStorage == NULL); |
| SkBitmapHeapEntry* entry = getEntry(slot); |
| if (entry) { |
| return &entry->fBitmap; |
| } |
| return NULL; |
| } |
| |
| /** |
| * Retrieves the bitmap from the specified slot in the heap |
| * |
| * @return The bitmap located at that slot or NULL if external storage is being used. |
| */ |
| virtual void releaseRef(int32_t slot) SK_OVERRIDE { |
| SkASSERT(fExternalStorage == NULL); |
| if (fOwnerCount != IGNORE_OWNERS) { |
| SkBitmapHeapEntry* entry = getEntry(slot); |
| if (entry) { |
| entry->releaseRef(); |
| } |
| } |
| } |
| |
| /** |
| * Inserts a bitmap into the heap. The stored version of bitmap is guaranteed to be immutable |
| * and is not dependent on the lifecycle of the provided bitmap. |
| * |
| * @param bitmap the bitmap to be inserted into the heap |
| * @return the slot in the heap where the bitmap is stored or INVALID_SLOT if the bitmap could |
| * not be added to the heap. If it was added the slot will remain valid... |
| * (1) indefinitely if no owner count has been specified. |
| * (2) until all owners have called releaseRef on the appropriate SkBitmapHeapEntry* |
| */ |
| int32_t insert(const SkBitmap& bitmap); |
| |
| /** |
| * Retrieves an entry from the heap at a given slot. |
| * |
| * @param slot the slot in the heap where a bitmap was stored. |
| * @return a SkBitmapHeapEntry that wraps the bitmap or NULL if external storage is used. |
| */ |
| SkBitmapHeapEntry* getEntry(int32_t slot) const { |
| SkASSERT(slot <= fStorage.count()); |
| if (fExternalStorage != NULL) { |
| return NULL; |
| } |
| return fStorage[slot]; |
| } |
| |
| /** |
| * Returns a count of the number of items currently in the heap |
| */ |
| int count() const { |
| SkASSERT(fExternalStorage != NULL || |
| fStorage.count() - fUnusedSlots.count() == fLookupTable.count()); |
| return fLookupTable.count(); |
| } |
| |
| /** |
| * Returns the total number of bytes allocated by the bitmaps in the heap |
| */ |
| size_t bytesAllocated() const { |
| return fBytesAllocated; |
| } |
| |
| /** |
| * Attempt to reduce the storage allocated. |
| * @param bytesToFree minimum number of bytes that should be attempted to |
| * be freed. |
| * @return number of bytes actually freed. |
| */ |
| size_t freeMemoryIfPossible(size_t bytesToFree); |
| |
| /** |
| * Defer any increments of owner counts until endAddingOwnersDeferral is called. So if an |
| * existing SkBitmap is inserted into the SkBitmapHeap, its corresponding SkBitmapHeapEntry will |
| * not have addReferences called on it, and the client does not need to make a corresponding |
| * call to releaseRef. Only meaningful if this SkBitmapHeap was created with an owner count not |
| * equal to IGNORE_OWNERS. |
| */ |
| void deferAddingOwners(); |
| |
| /** |
| * Resume adding references when duplicate SkBitmaps are inserted. |
| * @param add If true, add references to the SkBitmapHeapEntrys whose SkBitmaps were re-inserted |
| * while deferring. |
| */ |
| void endAddingOwnersDeferral(bool add); |
| |
| private: |
| struct LookupEntry { |
| LookupEntry(const SkBitmap& bm) |
| : fGenerationId(bm.getGenerationID()) |
| , fPixelOrigin(bm.pixelRefOrigin()) |
| , fWidth(bm.width()) |
| , fHeight(bm.height()) |
| , fMoreRecentlyUsed(NULL) |
| , fLessRecentlyUsed(NULL){} |
| |
| const uint32_t fGenerationId; // SkPixelRef GenerationID. |
| const SkIPoint fPixelOrigin; |
| const uint32_t fWidth; |
| const uint32_t fHeight; |
| |
| // TODO: Generalize the LRU caching mechanism |
| LookupEntry* fMoreRecentlyUsed; |
| LookupEntry* fLessRecentlyUsed; |
| |
| uint32_t fStorageSlot; // slot of corresponding bitmap in fStorage. |
| |
| /** |
| * Compare two LookupEntry pointers for sorting and searching. |
| */ |
| static bool Less(const LookupEntry& a, const LookupEntry& b); |
| }; |
| |
| /** |
| * Remove the entry from the lookup table. Also deletes the entry pointed |
| * to by the table. Therefore, if a pointer to that one was passed in, the |
| * pointer should no longer be used, since the object to which it points has |
| * been deleted. |
| * @return The index in the lookup table of the entry before removal. |
| */ |
| int removeEntryFromLookupTable(LookupEntry*); |
| |
| /** |
| * Searches for the bitmap in the lookup table and returns the bitmaps index within the table. |
| * If the bitmap was not already in the table it is added. |
| * |
| * @param key The key to search the lookup table, created from a bitmap. |
| * @param entry A pointer to a SkBitmapHeapEntry* that if non-null AND the bitmap is found |
| * in the lookup table is populated with the entry from the heap storage. |
| */ |
| int findInLookupTable(const LookupEntry& key, SkBitmapHeapEntry** entry); |
| |
| LookupEntry* findEntryToReplace(const SkBitmap& replacement); |
| bool copyBitmap(const SkBitmap& originalBitmap, SkBitmap& copiedBitmap); |
| |
| /** |
| * Remove a LookupEntry from the LRU, in preparation for either deleting or appending as most |
| * recent. Points the LookupEntry's old neighbors at each other, and sets fLeastRecentlyUsed |
| * (if there is still an entry left). Sets LookupEntry's fMoreRecentlyUsed to NULL and leaves |
| * its fLessRecentlyUsed unmodified. |
| */ |
| void removeFromLRU(LookupEntry* entry); |
| |
| /** |
| * Append a LookupEntry to the end of the LRU cache, marking it as the most |
| * recently used. Assumes that the LookupEntry is already in fLookupTable, |
| * but is not in the LRU cache. If it is in the cache, removeFromLRU should |
| * be called first. |
| */ |
| void appendToLRU(LookupEntry*); |
| |
| // searchable index that maps to entries in the heap |
| SkTDArray<LookupEntry*> fLookupTable; |
| |
| // heap storage |
| SkTDArray<SkBitmapHeapEntry*> fStorage; |
| // Used to mark slots in fStorage as deleted without actually deleting |
| // the slot so as not to mess up the numbering. |
| SkTDArray<int> fUnusedSlots; |
| ExternalStorage* fExternalStorage; |
| |
| LookupEntry* fMostRecentlyUsed; |
| LookupEntry* fLeastRecentlyUsed; |
| |
| const int32_t fPreferredCount; |
| const int32_t fOwnerCount; |
| size_t fBytesAllocated; |
| |
| bool fDeferAddingOwners; |
| SkTDArray<int> fDeferredEntries; |
| |
| typedef SkBitmapHeapReader INHERITED; |
| }; |
| |
| #endif // SkBitmapHeap_DEFINED |