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/*
* Copyright 2015 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef GrTextBlobCache_DEFINED
#define GrTextBlobCache_DEFINED
#include "GrAtlasTextContext.h"
#include "SkTDynamicHash.h"
#include "SkTextBlob.h"
class GrTextBlobCache {
public:
typedef GrAtlasTextContext::BitmapTextBlob BitmapTextBlob;
/**
* The callback function used by the cache when it is still over budget after a purge. The
* passed in 'data' is the same 'data' handed to setOverbudgetCallback.
*/
typedef void (*PFOverBudgetCB)(void* data);
GrTextBlobCache(PFOverBudgetCB cb, void* data)
: fPool(kPreAllocSize, kMinGrowthSize)
, fCallback(cb)
, fData(data) {
SkASSERT(cb && data);
}
~GrTextBlobCache();
// creates an uncached blob
BitmapTextBlob* createBlob(int glyphCount, int runCount, size_t maxVASize);
BitmapTextBlob* createBlob(const SkTextBlob* blob, size_t maxVAStride) {
int glyphCount = 0;
int runCount = 0;
BlobGlyphCount(&glyphCount, &runCount, blob);
BitmapTextBlob* cacheBlob = this->createBlob(glyphCount, runCount, maxVAStride);
return cacheBlob;
}
BitmapTextBlob* createCachedBlob(const SkTextBlob* blob, size_t maxVAStride) {
int glyphCount = 0;
int runCount = 0;
BlobGlyphCount(&glyphCount, &runCount, blob);
BitmapTextBlob* cacheBlob = this->createBlob(glyphCount, runCount, maxVAStride);
cacheBlob->fUniqueID = blob->uniqueID();
this->add(cacheBlob);
return cacheBlob;
}
BitmapTextBlob* find(uint32_t uniqueID) {
return fCache.find(uniqueID);
}
void remove(BitmapTextBlob* blob) {
fCache.remove(blob->fUniqueID);
fBlobList.remove(blob);
blob->unref();
}
void add(BitmapTextBlob* blob) {
fCache.add(blob);
fBlobList.addToHead(blob);
// If we are overbudget, then unref until we are below budget again
if (fPool.size() > kBudget) {
BitmapBlobList::Iter iter;
iter.init(fBlobList, BitmapBlobList::Iter::kTail_IterStart);
BitmapTextBlob* lruBlob = iter.get();
SkASSERT(lruBlob);
while (fPool.size() > kBudget && (lruBlob = iter.get()) && lruBlob != blob) {
fCache.remove(lruBlob->fUniqueID);
// Backup the iterator before removing and unrefing the blob
iter.prev();
fBlobList.remove(lruBlob);
lruBlob->unref();
}
// If we break out of the loop with lruBlob == blob, then we haven't purged enough
// use the call back and try to free some more. If we are still overbudget after this,
// then this single textblob is over our budget
if (lruBlob == blob) {
(*fCallback)(fData);
}
#ifdef SK_DEBUG
if (fPool.size() > kBudget) {
SkDebugf("Single textblob is larger than our whole budget");
}
#endif
}
}
void makeMRU(BitmapTextBlob* blob) {
if (fBlobList.head() == blob) {
return;
}
fBlobList.remove(blob);
fBlobList.addToHead(blob);
}
private:
// TODO move to SkTextBlob
void BlobGlyphCount(int* glyphCount, int* runCount, const SkTextBlob* blob) {
SkTextBlob::RunIterator itCounter(blob);
for (; !itCounter.done(); itCounter.next(), (*runCount)++) {
*glyphCount += itCounter.glyphCount();
}
}
typedef SkTInternalLList<BitmapTextBlob> BitmapBlobList;
// Budget was chosen to be ~4 megabytes. The min alloc and pre alloc sizes in the pool are
// based off of the largest cached textblob I have seen in the skps(a couple of kilobytes).
static const int kPreAllocSize = 1 << 17;
static const int kMinGrowthSize = 1 << 17;
static const int kBudget = 1 << 22;
BitmapBlobList fBlobList;
SkTDynamicHash<BitmapTextBlob, uint32_t> fCache;
GrMemoryPool fPool;
PFOverBudgetCB fCallback;
void* fData;
};
#endif
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