src/gpu/GrLayerCache.cpp - platform/external/skqp - Gitiles

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */

 #include "GrLayerAtlas.h"
 #include "GrContext.h"
 #include "GrDrawContext.h"
 #include "GrGpu.h"
 #include "GrLayerCache.h"
 #include "GrSurfacePriv.h"

 #ifdef SK_DEBUG
 void GrCachedLayer::validate(const GrTexture* backingTexture) const {
     SkASSERT(SK_InvalidGenID != fKey.pictureID());

     if (fTexture) {
         // If the layer is in some texture then it must occupy some rectangle
         SkASSERT(!fRect.isEmpty());
         if (!this->isAtlased()) {
             // If it isn't atlased then the rectangle should start at the origin
             SkASSERT(0.0f == fRect.fLeft && 0.0f == fRect.fTop);
         }
     } else {
         SkASSERT(fRect.isEmpty());
         SkASSERT(nullptr == fPlot);
         SkASSERT(!fLocked);     // layers without a texture cannot be locked
         SkASSERT(!fAtlased);    // can't be atlased if it doesn't have a texture
     }

     if (fPlot) {
         SkASSERT(fAtlased);
         // If a layer has a plot (i.e., is atlased) then it must point to
         // the backing texture. Additionally, its rect should be non-empty.
         SkASSERT(fTexture && backingTexture == fTexture);
         SkASSERT(!fRect.isEmpty());
     }

     if (fLocked) {
         // If a layer is locked it must have a texture (though it need not be
         // the atlas-backing texture) and occupy some space.
         SkASSERT(fTexture);
         SkASSERT(!fRect.isEmpty());
     }

     // Unfortunately there is a brief time where a layer can be locked
     // but not used, so we can only check the "used implies locked"
     // invariant.
     if (fUses > 0) {
         SkASSERT(fLocked);
     } else {
         SkASSERT(0 == fUses);
     }
 }

 class GrAutoValidateLayer : ::SkNoncopyable {
 public:
     GrAutoValidateLayer(GrTexture* backingTexture, const GrCachedLayer* layer)
         : fBackingTexture(backingTexture)
         , fLayer(layer) {
         if (fLayer) {
             fLayer->validate(backingTexture);
         }
     }
     ~GrAutoValidateLayer() {
         if (fLayer) {
             fLayer->validate(fBackingTexture);
         }
     }
     void setBackingTexture(GrTexture* backingTexture) {
         SkASSERT(nullptr == fBackingTexture || fBackingTexture == backingTexture);
         fBackingTexture = backingTexture;
     }

 private:
     const GrTexture* fBackingTexture;
     const GrCachedLayer* fLayer;
 };
 #endif

 GrLayerCache::GrLayerCache(GrContext* context)
     : fContext(context) {
     memset(fPlotLocks, 0, sizeof(fPlotLocks));
 }

 GrLayerCache::~GrLayerCache() {

     SkTDynamicHash<GrCachedLayer, GrCachedLayer::Key>::Iter iter(&fLayerHash);
     for (; !iter.done(); ++iter) {
         GrCachedLayer* layer = &(*iter);
         SkASSERT(0 == layer->uses());
         this->unlock(layer);
         delete layer;
     }

     SkASSERT(0 == fPictureHash.count());

     // The atlas only lets go of its texture when the atlas is deleted.
     fAtlas.free();
 }

 void GrLayerCache::initAtlas() {
     SkASSERT(nullptr == fAtlas.get());
     GR_STATIC_ASSERT(kNumPlotsX*kNumPlotsX == GrPictureInfo::kNumPlots);

     SkISize textureSize = SkISize::Make(kAtlasTextureWidth, kAtlasTextureHeight);
     fAtlas.reset(new GrLayerAtlas(fContext->textureProvider(), kSkia8888_GrPixelConfig,
                                   kRenderTarget_GrSurfaceFlag, textureSize,
                                   kNumPlotsX, kNumPlotsY));
 }

 void GrLayerCache::freeAll() {

     SkTDynamicHash<GrCachedLayer, GrCachedLayer::Key>::Iter iter(&fLayerHash);
     for (; !iter.done(); ++iter) {
         GrCachedLayer* layer = &(*iter);
         this->unlock(layer);
         delete layer;
     }
     fLayerHash.rewind();

     if (fAtlas) {
         fAtlas->resetPlots();
         fAtlas->detachBackingTexture();
     }
 }

 GrCachedLayer* GrLayerCache::createLayer(uint32_t pictureID,
                                          int start, int stop,
                                          const SkIRect& srcIR,
                                          const SkIRect& dstIR,
                                          const SkMatrix& initialMat,
                                          const int* key,
                                          int keySize,
                                          const SkPaint* paint) {
     SkASSERT(pictureID != SK_InvalidGenID && start >= 0 && stop > 0);

     GrCachedLayer* layer = new GrCachedLayer(pictureID, start, stop, srcIR, dstIR, initialMat, key,
                                              keySize, paint);
     fLayerHash.add(layer);
     return layer;
 }

 GrCachedLayer* GrLayerCache::findLayer(uint32_t pictureID, const SkMatrix& initialMat,
                                        const int* key, int keySize) {
     SkASSERT(pictureID != SK_InvalidGenID);
     return fLayerHash.find(GrCachedLayer::Key(pictureID, initialMat, key, keySize));
 }

 GrCachedLayer* GrLayerCache::findLayerOrCreate(uint32_t pictureID,
                                                int start, int stop,
                                                const SkIRect& srcIR,
                                                const SkIRect& dstIR,
                                                const SkMatrix& initialMat,
                                                const int* key,
                                                int keySize,
                                                const SkPaint* paint) {
     SkASSERT(pictureID != SK_InvalidGenID && start >= 0 && stop > 0);
     GrCachedLayer* layer = fLayerHash.find(GrCachedLayer::Key(pictureID, initialMat, key, keySize));
     if (nullptr == layer) {
         layer = this->createLayer(pictureID, start, stop,
                                   srcIR, dstIR, initialMat,
                                   key, keySize, paint);
     }

     return layer;
 }

 bool GrLayerCache::tryToAtlas(GrCachedLayer* layer,
                               const GrSurfaceDesc& desc,
                               bool* needsRendering) {
     SkDEBUGCODE(GrAutoValidateLayer avl(fAtlas ? fAtlas->getTextureOrNull() : nullptr, layer);)

     SkASSERT(PlausiblyAtlasable(desc.fWidth, desc.fHeight));
     SkASSERT(0 == desc.fSampleCnt);

     if (layer->locked()) {
         // This layer is already locked
         SkASSERT(fAtlas);
         SkASSERT(layer->isAtlased());
         SkASSERT(layer->rect().width() == desc.fWidth);
         SkASSERT(layer->rect().height() == desc.fHeight);
         *needsRendering = false;
         return true;
     }

     if (layer->isAtlased()) {
         SkASSERT(fAtlas);
         // Hooray it is still in the atlas - make sure it stays there
         layer->setLocked(true);
         this->incPlotLock(layer->plot()->id());
         *needsRendering = false;
         return true;
     } else {
         if (!fAtlas) {
             this->initAtlas();
             if (!fAtlas) {
                 return false;
             }
         }
         // Not in the atlas - will it fit?
         GrPictureInfo* pictInfo = fPictureHash.find(layer->pictureID());
         if (nullptr == pictInfo) {
             pictInfo = new GrPictureInfo(layer->pictureID());
             fPictureHash.add(pictInfo);
         }

         SkIPoint16 loc;
         for (int i = 0; i < 2; ++i) { // extra pass in case we fail to add but are able to purge
             GrLayerAtlas::Plot* plot = fAtlas->addToAtlas(&pictInfo->fPlotUsage,
                                                           desc.fWidth, desc.fHeight,
                                                           &loc);
             // addToAtlas can allocate the backing texture
             SkDEBUGCODE(avl.setBackingTexture(fAtlas->getTexture()));
             if (plot) {
 #if !GR_CACHE_HOISTED_LAYERS
                 pictInfo->incPlotUsage(plot->id());
 #endif
                 // The layer was successfully added to the atlas
                 const SkIRect bounds = SkIRect::MakeXYWH(loc.fX, loc.fY,
                                                          desc.fWidth, desc.fHeight);
                 layer->setTexture(fAtlas->getTexture(), bounds, true);
                 layer->setPlot(plot);
                 layer->setLocked(true);
                 this->incPlotLock(layer->plot()->id());
                 *needsRendering = true;
                 return true;
             }

             // The layer was rejected by the atlas (even though we know it is
             // plausibly atlas-able). See if a plot can be purged and try again.
             if (!this->purgePlots(true)) {
                 break;  // We weren't able to purge any plots
             }
         }

         if (pictInfo->fPlotUsage.isEmpty()) {
             fPictureHash.remove(pictInfo->fPictureID);
             delete pictInfo;
         }
     }

     return false;
 }

 bool GrLayerCache::lock(GrCachedLayer* layer, const GrSurfaceDesc& desc, bool* needsRendering) {
     if (layer->locked()) {
         // This layer is already locked
         *needsRendering = false;
         return true;
     }

     // TODO: make the test for exact match depend on the image filters themselves
     SkAutoTUnref<GrTexture> tex;
     if (layer->fFilter) {
         tex.reset(fContext->textureProvider()->createTexture(desc, true));
     } else {
         tex.reset(fContext->textureProvider()->createApproxTexture(desc));
     }

     if (!tex) {
         return false;
     }

     layer->setTexture(tex, SkIRect::MakeWH(desc.fWidth, desc.fHeight), false);
     layer->setLocked(true);
     *needsRendering = true;
     return true;
 }

 void GrLayerCache::unlock(GrCachedLayer* layer) {
     SkDEBUGCODE(GrAutoValidateLayer avl(fAtlas ? fAtlas->getTextureOrNull() : nullptr, layer);)

     if (nullptr == layer || !layer->locked()) {
         // invalid or not locked
         return;
     }

     if (layer->isAtlased()) {
         const int plotID = layer->plot()->id();

         this->decPlotLock(plotID);
         // At this point we could aggressively clear out un-locked plots but
         // by delaying we may be able to reuse some of the atlased layers later.
 #if !GR_CACHE_HOISTED_LAYERS
         // This testing code aggressively removes the atlased layers. This
         // can be used to separate the performance contribution of less
         // render target pingponging from that due to the re-use of cached layers
         GrPictureInfo* pictInfo = fPictureHash.find(layer->pictureID());
         SkASSERT(pictInfo);

         pictInfo->decPlotUsage(plotID);

         if (0 == pictInfo->plotUsage(plotID)) {
             pictInfo->fPlotUsage.removePlot(layer->plot());

             if (pictInfo->fPlotUsage.isEmpty()) {
                 fPictureHash.remove(pictInfo->fPictureID);
                 delete pictInfo;
             }
         }

         layer->setPlot(nullptr);
         layer->setTexture(nullptr, SkIRect::MakeEmpty(), false);
 #endif

     } else {
         layer->setTexture(nullptr, SkIRect::MakeEmpty(), false);
     }

     layer->setLocked(false);
 }

 #ifdef SK_DEBUG
 void GrLayerCache::validate() const {
     int plotLocks[kNumPlotsX * kNumPlotsY];
     memset(plotLocks, 0, sizeof(plotLocks));

     SkTDynamicHash<GrCachedLayer, GrCachedLayer::Key>::ConstIter iter(&fLayerHash);
     for (; !iter.done(); ++iter) {
         const GrCachedLayer* layer = &(*iter);

         layer->validate(fAtlas.get() ? fAtlas->getTextureOrNull() : nullptr);

         const GrPictureInfo* pictInfo = fPictureHash.find(layer->pictureID());
         if (!pictInfo) {
             // If there is no picture info for this picture then all of its
             // layers should be non-atlased.
             SkASSERT(!layer->isAtlased());
         }

         if (layer->plot()) {
             SkASSERT(pictInfo);
             SkASSERT(pictInfo->fPictureID == layer->pictureID());

             SkASSERT(pictInfo->fPlotUsage.contains(layer->plot()));
 #if !GR_CACHE_HOISTED_LAYERS
             SkASSERT(pictInfo->plotUsage(layer->plot()->id()) > 0);
 #endif

             if (layer->locked()) {
                 plotLocks[layer->plot()->id()]++;
             }
         }
     }

     for (int i = 0; i < kNumPlotsX*kNumPlotsY; ++i) {
         SkASSERT(plotLocks[i] == fPlotLocks[i]);
     }
 }

 class GrAutoValidateCache : ::SkNoncopyable {
 public:
     explicit GrAutoValidateCache(GrLayerCache* cache)
         : fCache(cache) {
         fCache->validate();
     }
     ~GrAutoValidateCache() {
         fCache->validate();
     }
 private:
     GrLayerCache* fCache;
 };
 #endif

 void GrLayerCache::purge(uint32_t pictureID) {

     SkDEBUGCODE(GrAutoValidateCache avc(this);)

     // We need to find all the layers associated with 'picture' and remove them.
     SkTDArray<GrCachedLayer*> toBeRemoved;

     SkTDynamicHash<GrCachedLayer, GrCachedLayer::Key>::Iter iter(&fLayerHash);
     for (; !iter.done(); ++iter) {
         if (pictureID == (*iter).pictureID()) {
             *toBeRemoved.append() = &(*iter);
         }
     }

     for (int i = 0; i < toBeRemoved.count(); ++i) {
         SkASSERT(0 == toBeRemoved[i]->uses());
         this->unlock(toBeRemoved[i]);
         fLayerHash.remove(GrCachedLayer::GetKey(*toBeRemoved[i]));
         delete toBeRemoved[i];
     }

     GrPictureInfo* pictInfo = fPictureHash.find(pictureID);
     if (pictInfo) {
         fPictureHash.remove(pictureID);
         delete pictInfo;
     }
 }

 bool GrLayerCache::purgePlots(bool justOne) {
     SkDEBUGCODE(GrAutoValidateCache avc(this);)
     SkASSERT(fAtlas);

     bool anyPurged = false;
     GrLayerAtlas::PlotIter iter;
     GrLayerAtlas::Plot* plot;
     for (plot = fAtlas->iterInit(&iter, GrLayerAtlas::kLRUFirst_IterOrder);
          plot;
          plot = iter.prev()) {
         if (fPlotLocks[plot->id()] > 0) {
             continue;
         }

         anyPurged = true;
         this->purgePlot(plot);
         if (justOne) {
             break;
         }
     }

     return anyPurged;
 }

 void GrLayerCache::purgePlot(GrLayerAtlas::Plot* plot) {
     SkASSERT(0 == fPlotLocks[plot->id()]);

     // We need to find all the layers in 'plot' and remove them.
     SkTDArray<GrCachedLayer*> toBeRemoved;

     SkTDynamicHash<GrCachedLayer, GrCachedLayer::Key>::Iter iter(&fLayerHash);
     for (; !iter.done(); ++iter) {
         if (plot == (*iter).plot()) {
             *toBeRemoved.append() = &(*iter);
         }
     }

     for (int i = 0; i < toBeRemoved.count(); ++i) {
         SkASSERT(0 == toBeRemoved[i]->uses());
         SkASSERT(!toBeRemoved[i]->locked());

         uint32_t pictureIDToRemove = toBeRemoved[i]->pictureID();

         // Aggressively remove layers and, if it becomes totally uncached, delete the picture info
         fLayerHash.remove(GrCachedLayer::GetKey(*toBeRemoved[i]));
         delete toBeRemoved[i];

         GrPictureInfo* pictInfo = fPictureHash.find(pictureIDToRemove);
         if (pictInfo) {
 #if !GR_CACHE_HOISTED_LAYERS
             SkASSERT(0 == pictInfo->plotUsage(plot->id()));
 #endif
             pictInfo->fPlotUsage.removePlot(plot);

             if (pictInfo->fPlotUsage.isEmpty()) {
                 fPictureHash.remove(pictInfo->fPictureID);
                 delete pictInfo;
             }
         }
     }

     plot->reset();
 }

 #if !GR_CACHE_HOISTED_LAYERS
 void GrLayerCache::purgeAll() {
     if (!fAtlas) {
         return;
     }

     this->purgePlots(false); // clear them all out

     SkASSERT(0 == fPictureHash.count());

     if (fAtlas->getTextureOrNull()) {
         SkAutoTUnref<GrDrawContext> drawContext(
                                     fContext->drawContext(fAtlas->getTexture()->asRenderTarget()));

         if (drawContext) {
             drawContext->discard();
         }
     }
 }
 #endif

 void GrLayerCache::begin() {
     if (!fAtlas) {
         return;
     }

     if (!fAtlas->reattachBackingTexture()) {
         // We weren't able to re-attach. Clear out all the atlased layers.
         this->purgePlots(false);
         SkASSERT(0 == fPictureHash.count());
     }
 #ifdef SK_DEBUG
     else {
         // we've reattached - everything had better make sense
         SkTDynamicHash<GrCachedLayer, GrCachedLayer::Key>::Iter iter(&fLayerHash);
         for (; !iter.done(); ++iter) {
             GrCachedLayer* layer = &(*iter);

             if (layer->isAtlased()) {
                 SkASSERT(fAtlas->getTexture() == layer->texture());
             }
         }
     }
 #endif
 }

 void GrLayerCache::end() {
     if (!fAtlas) {
         return;
     }

     // Adding this call will clear out all the layers in the atlas
     //this->purgePlots(false);

     fAtlas->detachBackingTexture();
 }

 void GrLayerCache::processDeletedPictures() {
     SkTArray<SkPicture::DeletionMessage> deletedPictures;
     fPictDeletionInbox.poll(&deletedPictures);

     for (int i = 0; i < deletedPictures.count(); i++) {
         this->purge(deletedPictures[i].fUniqueID);
     }
 }

 #ifdef SK_DEVELOPER
 void GrLayerCache::writeLayersToDisk(const SkString& dirName) {

     if (fAtlas) {
         GrTexture* atlasTexture = fAtlas->getTextureOrNull();
         if (nullptr != atlasTexture) {
             SkString fileName(dirName);
             fileName.append("\\atlas.png");

             atlasTexture->surfacePriv().savePixels(fileName.c_str());
         }
     }

     SkTDynamicHash<GrCachedLayer, GrCachedLayer::Key>::Iter iter(&fLayerHash);
     for (; !iter.done(); ++iter) {
         GrCachedLayer* layer = &(*iter);

         if (layer->isAtlased() || !layer->texture()) {
             continue;
         }

         SkString fileName(dirName);
         fileName.appendf("\\%d", layer->fKey.pictureID());
         for (int i = 0; i < layer->fKey.keySize(); ++i) {
             fileName.appendf("-%d", layer->fKey.key()[i]);
         }
         fileName.appendf(".png");

         layer->texture()->surfacePriv().savePixels(fileName.c_str());
     }
 }
 #endif
	/*
	* Copyright 2014 Google Inc.
	*
	* Use of this source code is governed by a BSD-style license that can be
	* found in the LICENSE file.
	*/

	#include "GrLayerAtlas.h"
	#include "GrContext.h"
	#include "GrDrawContext.h"
	#include "GrGpu.h"
	#include "GrLayerCache.h"
	#include "GrSurfacePriv.h"

	#ifdef SK_DEBUG
	void GrCachedLayer::validate(const GrTexture* backingTexture) const {
	SkASSERT(SK_InvalidGenID != fKey.pictureID());

	if (fTexture) {
	// If the layer is in some texture then it must occupy some rectangle
	SkASSERT(!fRect.isEmpty());
	if (!this->isAtlased()) {
	// If it isn't atlased then the rectangle should start at the origin
	SkASSERT(0.0f == fRect.fLeft && 0.0f == fRect.fTop);
	}
	} else {
	SkASSERT(fRect.isEmpty());
	SkASSERT(nullptr == fPlot);
	SkASSERT(!fLocked); // layers without a texture cannot be locked
	SkASSERT(!fAtlased); // can't be atlased if it doesn't have a texture
	}

	if (fPlot) {
	SkASSERT(fAtlased);
	// If a layer has a plot (i.e., is atlased) then it must point to
	// the backing texture. Additionally, its rect should be non-empty.
	SkASSERT(fTexture && backingTexture == fTexture);
	SkASSERT(!fRect.isEmpty());
	}

	if (fLocked) {
	// If a layer is locked it must have a texture (though it need not be
	// the atlas-backing texture) and occupy some space.
	SkASSERT(fTexture);
	SkASSERT(!fRect.isEmpty());
	}

	// Unfortunately there is a brief time where a layer can be locked
	// but not used, so we can only check the "used implies locked"
	// invariant.
	if (fUses > 0) {
	SkASSERT(fLocked);
	} else {
	SkASSERT(0 == fUses);
	}
	}

	class GrAutoValidateLayer : ::SkNoncopyable {
	public:
	GrAutoValidateLayer(GrTexture* backingTexture, const GrCachedLayer* layer)
	: fBackingTexture(backingTexture)
	, fLayer(layer) {
	if (fLayer) {
	fLayer->validate(backingTexture);
	}
	}
	~GrAutoValidateLayer() {
	if (fLayer) {
	fLayer->validate(fBackingTexture);
	}
	}
	void setBackingTexture(GrTexture* backingTexture) {
	SkASSERT(nullptr == fBackingTexture \|\| fBackingTexture == backingTexture);
	fBackingTexture = backingTexture;
	}

	private:
	const GrTexture* fBackingTexture;
	const GrCachedLayer* fLayer;
	};
	#endif

	GrLayerCache::GrLayerCache(GrContext* context)
	: fContext(context) {
	memset(fPlotLocks, 0, sizeof(fPlotLocks));
	}

	GrLayerCache::~GrLayerCache() {

	SkTDynamicHash<GrCachedLayer, GrCachedLayer::Key>::Iter iter(&fLayerHash);
	for (; !iter.done(); ++iter) {
	GrCachedLayer* layer = &(*iter);
	SkASSERT(0 == layer->uses());
	this->unlock(layer);
	delete layer;
	}

	SkASSERT(0 == fPictureHash.count());

	// The atlas only lets go of its texture when the atlas is deleted.
	fAtlas.free();
	}

	void GrLayerCache::initAtlas() {
	SkASSERT(nullptr == fAtlas.get());
	GR_STATIC_ASSERT(kNumPlotsX*kNumPlotsX == GrPictureInfo::kNumPlots);

	SkISize textureSize = SkISize::Make(kAtlasTextureWidth, kAtlasTextureHeight);
	fAtlas.reset(new GrLayerAtlas(fContext->textureProvider(), kSkia8888_GrPixelConfig,
	kRenderTarget_GrSurfaceFlag, textureSize,
	kNumPlotsX, kNumPlotsY));
	}

	void GrLayerCache::freeAll() {

	SkTDynamicHash<GrCachedLayer, GrCachedLayer::Key>::Iter iter(&fLayerHash);
	for (; !iter.done(); ++iter) {
	GrCachedLayer* layer = &(*iter);
	this->unlock(layer);
	delete layer;
	}
	fLayerHash.rewind();

	if (fAtlas) {
	fAtlas->resetPlots();
	fAtlas->detachBackingTexture();
	}
	}

	GrCachedLayer* GrLayerCache::createLayer(uint32_t pictureID,
	int start, int stop,
	const SkIRect& srcIR,
	const SkIRect& dstIR,
	const SkMatrix& initialMat,
	const int* key,
	int keySize,
	const SkPaint* paint) {
	SkASSERT(pictureID != SK_InvalidGenID && start >= 0 && stop > 0);

	GrCachedLayer* layer = new GrCachedLayer(pictureID, start, stop, srcIR, dstIR, initialMat, key,
	keySize, paint);
	fLayerHash.add(layer);
	return layer;
	}

	GrCachedLayer* GrLayerCache::findLayer(uint32_t pictureID, const SkMatrix& initialMat,
	const int* key, int keySize) {
	SkASSERT(pictureID != SK_InvalidGenID);
	return fLayerHash.find(GrCachedLayer::Key(pictureID, initialMat, key, keySize));
	}

	GrCachedLayer* GrLayerCache::findLayerOrCreate(uint32_t pictureID,
	int start, int stop,
	const SkIRect& srcIR,
	const SkIRect& dstIR,
	const SkMatrix& initialMat,
	const int* key,
	int keySize,
	const SkPaint* paint) {
	SkASSERT(pictureID != SK_InvalidGenID && start >= 0 && stop > 0);
	GrCachedLayer* layer = fLayerHash.find(GrCachedLayer::Key(pictureID, initialMat, key, keySize));
	if (nullptr == layer) {
	layer = this->createLayer(pictureID, start, stop,
	srcIR, dstIR, initialMat,
	key, keySize, paint);
	}

	return layer;
	}

	bool GrLayerCache::tryToAtlas(GrCachedLayer* layer,
	const GrSurfaceDesc& desc,
	bool* needsRendering) {
	SkDEBUGCODE(GrAutoValidateLayer avl(fAtlas ? fAtlas->getTextureOrNull() : nullptr, layer);)

	SkASSERT(PlausiblyAtlasable(desc.fWidth, desc.fHeight));
	SkASSERT(0 == desc.fSampleCnt);

	if (layer->locked()) {
	// This layer is already locked
	SkASSERT(fAtlas);
	SkASSERT(layer->isAtlased());
	SkASSERT(layer->rect().width() == desc.fWidth);
	SkASSERT(layer->rect().height() == desc.fHeight);
	*needsRendering = false;
	return true;
	}

	if (layer->isAtlased()) {
	SkASSERT(fAtlas);
	// Hooray it is still in the atlas - make sure it stays there
	layer->setLocked(true);
	this->incPlotLock(layer->plot()->id());
	*needsRendering = false;
	return true;
	} else {
	if (!fAtlas) {
	this->initAtlas();
	if (!fAtlas) {
	return false;
	}
	}
	// Not in the atlas - will it fit?
	GrPictureInfo* pictInfo = fPictureHash.find(layer->pictureID());
	if (nullptr == pictInfo) {
	pictInfo = new GrPictureInfo(layer->pictureID());
	fPictureHash.add(pictInfo);
	}

	SkIPoint16 loc;
	for (int i = 0; i < 2; ++i) { // extra pass in case we fail to add but are able to purge
	GrLayerAtlas::Plot* plot = fAtlas->addToAtlas(&pictInfo->fPlotUsage,
	desc.fWidth, desc.fHeight,
	&loc);
	// addToAtlas can allocate the backing texture
	SkDEBUGCODE(avl.setBackingTexture(fAtlas->getTexture()));
	if (plot) {
	#if !GR_CACHE_HOISTED_LAYERS
	pictInfo->incPlotUsage(plot->id());
	#endif
	// The layer was successfully added to the atlas
	const SkIRect bounds = SkIRect::MakeXYWH(loc.fX, loc.fY,
	desc.fWidth, desc.fHeight);
	layer->setTexture(fAtlas->getTexture(), bounds, true);
	layer->setPlot(plot);
	layer->setLocked(true);
	this->incPlotLock(layer->plot()->id());
	*needsRendering = true;
	return true;
	}

	// The layer was rejected by the atlas (even though we know it is
	// plausibly atlas-able). See if a plot can be purged and try again.
	if (!this->purgePlots(true)) {
	break; // We weren't able to purge any plots
	}
	}

	if (pictInfo->fPlotUsage.isEmpty()) {
	fPictureHash.remove(pictInfo->fPictureID);
	delete pictInfo;
	}
	}

	return false;
	}

	bool GrLayerCache::lock(GrCachedLayer* layer, const GrSurfaceDesc& desc, bool* needsRendering) {
	if (layer->locked()) {
	// This layer is already locked
	*needsRendering = false;
	return true;
	}

	// TODO: make the test for exact match depend on the image filters themselves
	SkAutoTUnref<GrTexture> tex;
	if (layer->fFilter) {
	tex.reset(fContext->textureProvider()->createTexture(desc, true));
	} else {
	tex.reset(fContext->textureProvider()->createApproxTexture(desc));
	}

	if (!tex) {
	return false;
	}

	layer->setTexture(tex, SkIRect::MakeWH(desc.fWidth, desc.fHeight), false);
	layer->setLocked(true);
	*needsRendering = true;
	return true;
	}

	void GrLayerCache::unlock(GrCachedLayer* layer) {
	SkDEBUGCODE(GrAutoValidateLayer avl(fAtlas ? fAtlas->getTextureOrNull() : nullptr, layer);)

	if (nullptr == layer \|\| !layer->locked()) {
	// invalid or not locked
	return;
	}

	if (layer->isAtlased()) {
	const int plotID = layer->plot()->id();

	this->decPlotLock(plotID);
	// At this point we could aggressively clear out un-locked plots but
	// by delaying we may be able to reuse some of the atlased layers later.
	#if !GR_CACHE_HOISTED_LAYERS
	// This testing code aggressively removes the atlased layers. This
	// can be used to separate the performance contribution of less
	// render target pingponging from that due to the re-use of cached layers
	GrPictureInfo* pictInfo = fPictureHash.find(layer->pictureID());
	SkASSERT(pictInfo);

	pictInfo->decPlotUsage(plotID);

	if (0 == pictInfo->plotUsage(plotID)) {
	pictInfo->fPlotUsage.removePlot(layer->plot());

	if (pictInfo->fPlotUsage.isEmpty()) {
	fPictureHash.remove(pictInfo->fPictureID);
	delete pictInfo;
	}
	}

	layer->setPlot(nullptr);
	layer->setTexture(nullptr, SkIRect::MakeEmpty(), false);
	#endif

	} else {
	layer->setTexture(nullptr, SkIRect::MakeEmpty(), false);
	}

	layer->setLocked(false);
	}

	#ifdef SK_DEBUG
	void GrLayerCache::validate() const {
	int plotLocks[kNumPlotsX * kNumPlotsY];
	memset(plotLocks, 0, sizeof(plotLocks));

	SkTDynamicHash<GrCachedLayer, GrCachedLayer::Key>::ConstIter iter(&fLayerHash);
	for (; !iter.done(); ++iter) {
	const GrCachedLayer* layer = &(*iter);

	layer->validate(fAtlas.get() ? fAtlas->getTextureOrNull() : nullptr);

	const GrPictureInfo* pictInfo = fPictureHash.find(layer->pictureID());
	if (!pictInfo) {
	// If there is no picture info for this picture then all of its
	// layers should be non-atlased.
	SkASSERT(!layer->isAtlased());
	}

	if (layer->plot()) {
	SkASSERT(pictInfo);
	SkASSERT(pictInfo->fPictureID == layer->pictureID());

	SkASSERT(pictInfo->fPlotUsage.contains(layer->plot()));
	#if !GR_CACHE_HOISTED_LAYERS
	SkASSERT(pictInfo->plotUsage(layer->plot()->id()) > 0);
	#endif

	if (layer->locked()) {
	plotLocks[layer->plot()->id()]++;
	}
	}
	}

	for (int i = 0; i < kNumPlotsX*kNumPlotsY; ++i) {
	SkASSERT(plotLocks[i] == fPlotLocks[i]);
	}
	}

	class GrAutoValidateCache : ::SkNoncopyable {
	public:
	explicit GrAutoValidateCache(GrLayerCache* cache)
	: fCache(cache) {
	fCache->validate();
	}
	~GrAutoValidateCache() {
	fCache->validate();
	}
	private:
	GrLayerCache* fCache;
	};
	#endif

	void GrLayerCache::purge(uint32_t pictureID) {

	SkDEBUGCODE(GrAutoValidateCache avc(this);)

	// We need to find all the layers associated with 'picture' and remove them.
	SkTDArray<GrCachedLayer*> toBeRemoved;

	SkTDynamicHash<GrCachedLayer, GrCachedLayer::Key>::Iter iter(&fLayerHash);
	for (; !iter.done(); ++iter) {
	if (pictureID == (*iter).pictureID()) {
	toBeRemoved.append() = &(iter);
	}
	}

	for (int i = 0; i < toBeRemoved.count(); ++i) {
	SkASSERT(0 == toBeRemoved[i]->uses());
	this->unlock(toBeRemoved[i]);
	fLayerHash.remove(GrCachedLayer::GetKey(*toBeRemoved[i]));
	delete toBeRemoved[i];
	}

	GrPictureInfo* pictInfo = fPictureHash.find(pictureID);
	if (pictInfo) {
	fPictureHash.remove(pictureID);
	delete pictInfo;
	}
	}

	bool GrLayerCache::purgePlots(bool justOne) {
	SkDEBUGCODE(GrAutoValidateCache avc(this);)
	SkASSERT(fAtlas);

	bool anyPurged = false;
	GrLayerAtlas::PlotIter iter;
	GrLayerAtlas::Plot* plot;
	for (plot = fAtlas->iterInit(&iter, GrLayerAtlas::kLRUFirst_IterOrder);
	plot;
	plot = iter.prev()) {
	if (fPlotLocks[plot->id()] > 0) {
	continue;
	}

	anyPurged = true;
	this->purgePlot(plot);
	if (justOne) {
	break;
	}
	}

	return anyPurged;
	}

	void GrLayerCache::purgePlot(GrLayerAtlas::Plot* plot) {
	SkASSERT(0 == fPlotLocks[plot->id()]);

	// We need to find all the layers in 'plot' and remove them.
	SkTDArray<GrCachedLayer*> toBeRemoved;

	SkTDynamicHash<GrCachedLayer, GrCachedLayer::Key>::Iter iter(&fLayerHash);
	for (; !iter.done(); ++iter) {
	if (plot == (*iter).plot()) {
	toBeRemoved.append() = &(iter);
	}
	}

	for (int i = 0; i < toBeRemoved.count(); ++i) {
	SkASSERT(0 == toBeRemoved[i]->uses());
	SkASSERT(!toBeRemoved[i]->locked());

	uint32_t pictureIDToRemove = toBeRemoved[i]->pictureID();

	// Aggressively remove layers and, if it becomes totally uncached, delete the picture info
	fLayerHash.remove(GrCachedLayer::GetKey(*toBeRemoved[i]));
	delete toBeRemoved[i];

	GrPictureInfo* pictInfo = fPictureHash.find(pictureIDToRemove);
	if (pictInfo) {
	#if !GR_CACHE_HOISTED_LAYERS
	SkASSERT(0 == pictInfo->plotUsage(plot->id()));
	#endif
	pictInfo->fPlotUsage.removePlot(plot);

	if (pictInfo->fPlotUsage.isEmpty()) {
	fPictureHash.remove(pictInfo->fPictureID);
	delete pictInfo;
	}
	}
	}

	plot->reset();
	}

	#if !GR_CACHE_HOISTED_LAYERS
	void GrLayerCache::purgeAll() {
	if (!fAtlas) {
	return;
	}

	this->purgePlots(false); // clear them all out

	SkASSERT(0 == fPictureHash.count());

	if (fAtlas->getTextureOrNull()) {
	SkAutoTUnref<GrDrawContext> drawContext(
	fContext->drawContext(fAtlas->getTexture()->asRenderTarget()));

	if (drawContext) {
	drawContext->discard();
	}
	}
	}
	#endif

	void GrLayerCache::begin() {
	if (!fAtlas) {
	return;
	}

	if (!fAtlas->reattachBackingTexture()) {
	// We weren't able to re-attach. Clear out all the atlased layers.
	this->purgePlots(false);
	SkASSERT(0 == fPictureHash.count());
	}
	#ifdef SK_DEBUG
	else {
	// we've reattached - everything had better make sense
	SkTDynamicHash<GrCachedLayer, GrCachedLayer::Key>::Iter iter(&fLayerHash);
	for (; !iter.done(); ++iter) {
	GrCachedLayer* layer = &(*iter);

	if (layer->isAtlased()) {
	SkASSERT(fAtlas->getTexture() == layer->texture());
	}
	}
	}
	#endif
	}

	void GrLayerCache::end() {
	if (!fAtlas) {
	return;
	}

	// Adding this call will clear out all the layers in the atlas
	//this->purgePlots(false);

	fAtlas->detachBackingTexture();
	}

	void GrLayerCache::processDeletedPictures() {
	SkTArray<SkPicture::DeletionMessage> deletedPictures;
	fPictDeletionInbox.poll(&deletedPictures);

	for (int i = 0; i < deletedPictures.count(); i++) {
	this->purge(deletedPictures[i].fUniqueID);
	}
	}

	#ifdef SK_DEVELOPER
	void GrLayerCache::writeLayersToDisk(const SkString& dirName) {

	if (fAtlas) {
	GrTexture* atlasTexture = fAtlas->getTextureOrNull();
	if (nullptr != atlasTexture) {
	SkString fileName(dirName);
	fileName.append("\\atlas.png");

	atlasTexture->surfacePriv().savePixels(fileName.c_str());
	}
	}

	SkTDynamicHash<GrCachedLayer, GrCachedLayer::Key>::Iter iter(&fLayerHash);
	for (; !iter.done(); ++iter) {
	GrCachedLayer* layer = &(*iter);

	if (layer->isAtlased() \|\| !layer->texture()) {
	continue;
	}

	SkString fileName(dirName);
	fileName.appendf("\\%d", layer->fKey.pictureID());
	for (int i = 0; i < layer->fKey.keySize(); ++i) {
	fileName.appendf("-%d", layer->fKey.key()[i]);
	}
	fileName.appendf(".png");

	layer->texture()->surfacePriv().savePixels(fileName.c_str());
	}
	}
	#endif