text: /*
   * 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 "GrAtlas.h"
  #include "GrGpu.h"
  #include "GrLayerCache.h"
  
  DECLARE_SKMESSAGEBUS_MESSAGE(GrPictureDeletedMessage);
  
  #ifdef SK_DEBUG
  void GrCachedLayer::validate(const GrTexture* backingTexture) const {
      SkASSERT(SK_InvalidGenID != fKey.pictureID());
      SkASSERT(fKey.start() > 0 && fKey.stop() > 0);
  
  
      if (NULL != 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(NULL == fPlot);
          SkASSERT(!fLocked);     // layers without a texture cannot be locked
      }
  
      if (NULL != fPlot) {
          // 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(NULL != 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(NULL != fTexture);
          SkASSERT(!fRect.isEmpty());
      }
  }
  
  class GrAutoValidateLayer : ::SkNoncopyable {
  public:
      GrAutoValidateLayer(GrTexture* backingTexture, const GrCachedLayer* layer) 
          : fBackingTexture(backingTexture)
          , fLayer(layer) {
          if (NULL != fLayer) {
              fLayer->validate(backingTexture);
          }
      }
      ~GrAutoValidateLayer() {
          if (NULL != fLayer) {
              fLayer->validate(fBackingTexture);
          }
      }
      void setBackingTexture(GrTexture* backingTexture) {
          SkASSERT(NULL == fBackingTexture || fBackingTexture == backingTexture);
          fBackingTexture = backingTexture;
      }
  
  private:
      const GrTexture* fBackingTexture;
      const GrCachedLayer* fLayer;
  };
  #endif
  
  GrLayerCache::GrLayerCache(GrContext* context)
      : fContext(context) {
      this->initAtlas();
      memset(fPlotLocks, 0, sizeof(fPlotLocks));
  }
  
  GrLayerCache::~GrLayerCache() {
  
      SkTDynamicHash<GrCachedLayer, GrCachedLayer::Key>::Iter iter(&fLayerHash);
      for (; !iter.done(); ++iter) {
          GrCachedLayer* layer = &(*iter);
          this->unlock(layer);
          SkDELETE(layer);
      }
  
      // The atlas only lets go of its texture when the atlas is deleted. 
      fAtlas.free();    
  }
  
  void GrLayerCache::initAtlas() {
      SkASSERT(NULL == fAtlas.get());
  
      SkISize textureSize = SkISize::Make(kAtlasTextureWidth, kAtlasTextureHeight);
      fAtlas.reset(SkNEW_ARGS(GrAtlas, (fContext->getGpu(), kSkia8888_GrPixelConfig,
                                        kRenderTarget_GrTextureFlagBit,
                                        textureSize, kNumPlotsX, kNumPlotsY, false)));
  }
  
  void GrLayerCache::freeAll() {
  
      SkTDynamicHash<GrCachedLayer, GrCachedLayer::Key>::Iter iter(&fLayerHash);
      for (; !iter.done(); ++iter) {
          GrCachedLayer* layer = &(*iter);
          this->unlock(layer);
          SkDELETE(layer);
      }
      fLayerHash.rewind();
  
      // The atlas only lets go of its texture when the atlas is deleted. 
      fAtlas.free();
      // GrLayerCache always assumes an atlas exists so recreate it. The atlas 
      // lazily allocates a replacement texture so reallocating a new 
      // atlas here won't disrupt a GrContext::abandonContext or freeGpuResources.
      // TODO: Make GrLayerCache lazily allocate the atlas manager?
      this->initAtlas();
  }
  
  GrCachedLayer* GrLayerCache::createLayer(uint32_t pictureID, 
                                           int start, int stop, 
                                           const SkMatrix& ctm) {
      SkASSERT(pictureID != SK_InvalidGenID && start > 0 && stop > 0);
  
      GrCachedLayer* layer = SkNEW_ARGS(GrCachedLayer, (pictureID, start, stop, ctm));
      fLayerHash.add(layer);
      return layer;
  }
  
  GrCachedLayer* GrLayerCache::findLayer(uint32_t pictureID,
                                         int start, int stop, 
                                         const SkMatrix& ctm) {
      SkASSERT(pictureID != SK_InvalidGenID && start > 0 && stop > 0);
      return fLayerHash.find(GrCachedLayer::Key(pictureID, start, stop, ctm));
  }
  
  GrCachedLayer* GrLayerCache::findLayerOrCreate(uint32_t pictureID,
                                                 int start, int stop,
                                                 const SkMatrix& ctm) {
      SkASSERT(pictureID != SK_InvalidGenID && start > 0 && stop > 0);
      GrCachedLayer* layer = fLayerHash.find(GrCachedLayer::Key(pictureID, start, stop, ctm));
      if (NULL == layer) {
          layer = this->createLayer(pictureID, start, stop, ctm);
      }
  
      return layer;
  }
  
  bool GrLayerCache::lock(GrCachedLayer* layer, const GrTextureDesc& desc, bool dontAtlas) {
      SkDEBUGCODE(GrAutoValidateLayer avl(fAtlas->getTexture(), layer);)
  
      if (layer->locked()) {
          // This layer is already locked
  #ifdef SK_DEBUG
          if (layer->isAtlased()) {
              // It claims to be atlased
              SkASSERT(!dontAtlas);
              SkASSERT(layer->rect().width() == desc.fWidth);
              SkASSERT(layer->rect().height() == desc.fHeight);
          }
  #endif
          return false;
      }
  
      if (layer->isAtlased()) {
          // Hooray it is still in the atlas - make sure it stays there
          SkASSERT(!dontAtlas);
          layer->setLocked(true);
          fPlotLocks[layer->plot()->id()]++;
          return false;
      } else if (!dontAtlas && PlausiblyAtlasable(desc.fWidth, desc.fHeight)) {
          // Not in the atlas - will it fit?
          GrPictureInfo* pictInfo = fPictureHash.find(layer->pictureID());
          if (NULL == pictInfo) {
              pictInfo = SkNEW_ARGS(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
              GrPlot* plot = fAtlas->addToAtlas(&pictInfo->fPlotUsage,
                                                desc.fWidth, desc.fHeight,
                                                NULL, &loc);
              // addToAtlas can allocate the backing texture
              SkDEBUGCODE(avl.setBackingTexture(fAtlas->getTexture()));
              if (NULL != plot) {
                  // The layer was successfully added to the atlas
                  GrIRect16 bounds = GrIRect16::MakeXYWH(loc.fX, loc.fY,
                                                         SkToS16(desc.fWidth),
                                                         SkToS16(desc.fHeight));
                  layer->setTexture(fAtlas->getTexture(), bounds);
                  layer->setPlot(plot);
                  layer->setLocked(true);
                  fPlotLocks[layer->plot()->id()]++;
                  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->purgePlot()) {
                  break;  // We weren't able to purge any plots
              }
          }
      }
  
      // The texture wouldn't fit in the cache - give it it's own texture.
      // This path always uses a new scratch texture and (thus) doesn't cache anything.
      // This can yield a lot of re-rendering
      SkAutoTUnref<GrTexture> tex(fContext->lockAndRefScratchTexture(desc,
                                                          GrContext::kApprox_ScratchTexMatch));
  
      layer->setTexture(tex, GrIRect16::MakeWH(SkToS16(desc.fWidth), SkToS16(desc.fHeight)));
      layer->setLocked(true);
      return true;
  }
  
  void GrLayerCache::unlock(GrCachedLayer* layer) {
      SkDEBUGCODE(GrAutoValidateLayer avl(fAtlas->getTexture(), layer);)
  
      if (NULL == layer || !layer->locked()) {
          // invalid or not locked
          return;
      }
  
      if (layer->isAtlased()) {
          const int plotID = layer->plot()->id();
  
          SkASSERT(fPlotLocks[plotID] > 0);
          fPlotLocks[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 DISABLE_CACHING
          // 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(NULL != pictInfo);
          
          GrAtlas::RemovePlot(&pictInfo->fPlotUsage, layer->plot());
          
          layer->setPlot(NULL);
          layer->setTexture(NULL, GrIRect16::MakeEmpty());
  #endif
  
      } else {
          fContext->unlockScratchTexture(layer->texture());
          layer->setTexture(NULL, GrIRect16::MakeEmpty());
      }
  
      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->getTexture());
  
          const GrPictureInfo* pictInfo = fPictureHash.find(layer->pictureID());
          if (NULL != pictInfo) {
              // In aggressive cleanup mode a picture info should only exist if
              // it has some atlased layers
  #if !DISABLE_CACHING
              SkASSERT(!pictInfo->fPlotUsage.isEmpty());
  #endif
          } else {
              // If there is no picture info for this layer then all of its
              // layers should be non-atlased.
              SkASSERT(!layer->isAtlased());
          }
  
          if (NULL != layer->plot()) {
              SkASSERT(NULL != pictInfo);
              SkASSERT(pictInfo->fPictureID == layer->pictureID());
  
              SkASSERT(pictInfo->fPlotUsage.contains(layer->plot()));
  
              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) {
          this->unlock(toBeRemoved[i]);
          fLayerHash.remove(GrCachedLayer::GetKey(*toBeRemoved[i]));
          SkDELETE(toBeRemoved[i]);
      }
  
      GrPictureInfo* pictInfo = fPictureHash.find(pictureID);
      if (NULL != pictInfo) {
          fPictureHash.remove(pictureID);
          SkDELETE(pictInfo);
      }
  }
  
  bool GrLayerCache::purgePlot() {
      SkDEBUGCODE(GrAutoValidateCache avc(this);)
  
      GrAtlas::PlotIter iter;
      GrPlot* plot;
      for (plot = fAtlas->iterInit(&iter, GrAtlas::kLRUFirst_IterOrder);
           NULL != plot;
           plot = iter.prev()) {
          if (fPlotLocks[plot->id()] > 0) {
              continue;
          }
  
          this->purgePlot(plot);
          return true;
      }
  
      return false;
  }
  
  void GrLayerCache::purgePlot(GrPlot* 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(!toBeRemoved[i]->locked());
  
          GrPictureInfo* pictInfo = fPictureHash.find(toBeRemoved[i]->pictureID());
          SkASSERT(NULL != pictInfo);
  
          GrAtlas::RemovePlot(&pictInfo->fPlotUsage, plot);
  
          // Aggressively remove layers and, if now totally uncached, picture info
          fLayerHash.remove(GrCachedLayer::GetKey(*toBeRemoved[i]));
          SkDELETE(toBeRemoved[i]);
  
          if (pictInfo->fPlotUsage.isEmpty()) {
              fPictureHash.remove(pictInfo->fPictureID);
              SkDELETE(pictInfo);
          }
      }
  
      plot->resetRects();
  }
  
  void GrLayerCache::purgeAll() {
      GrAtlas::PlotIter iter;
      GrPlot* plot;
      for (plot = fAtlas->iterInit(&iter, GrAtlas::kLRUFirst_IterOrder);
           NULL != plot;
           plot = iter.prev()) {
          SkASSERT(0 == fPlotLocks[plot->id()]);
  
          this->purgePlot(plot);
      }
  }
  
  class GrPictureDeletionListener : public SkPicture::DeletionListener {
      virtual void onDeletion(uint32_t pictureID) SK_OVERRIDE{
          const GrPictureDeletedMessage message = { pictureID };
          SkMessageBus<GrPictureDeletedMessage>::Post(message);
      }
  };
  
  void GrLayerCache::trackPicture(const SkPicture* picture) {
      if (NULL == fDeletionListener) {
          fDeletionListener.reset(SkNEW(GrPictureDeletionListener));
      }
  
      picture->addDeletionListener(fDeletionListener);
  }
  
  void GrLayerCache::processDeletedPictures() {
      SkTDArray<GrPictureDeletedMessage> deletedPictures;
      fPictDeletionInbox.poll(&deletedPictures);
  
      for (int i = 0; i < deletedPictures.count(); i++) {
          this->purge(deletedPictures[i].pictureID);
      }
  }
  
  