Update Layer Hoisting to store its atlas texture in the resource cache

src/gpu/GrLayerCache.cpp

 /*
  * 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);
@@ skipping 69 matching lines @@
 void GrLayerCache::freeAll() {
 
     SkTDynamicHash<GrCachedLayer, GrCachedLayer::Key>::Iter iter(&fLayerHash);
     for (; !iter.done(); ++iter) {
         GrCachedLayer* layer = &(*iter);
         this->unlock(layer);
         delete layer;
     }
     fLayerHash.rewind();
 
-    // The atlas only lets go of its texture when the atlas is deleted.
-    fAtlas.free();
+    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) {
@@ skipping 26 matching lines @@
                                   srcIR, dstIR, initialMat,
                                   key, keySize, paint);
     }
 
     return layer;
 }
 
 bool GrLayerCache::tryToAtlas(GrCachedLayer* layer,
                               const GrSurfaceDesc& desc,
                               bool* needsRendering) {
-    SkDEBUGCODE(GrAutoValidateLayer avl(fAtlas ? fAtlas->getTexture() : nullptr, layer);)
+    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);
@@ skipping 29 matching lines @@
                                                           &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);
+                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->purgePlot()) {
+            if (!this->purgePlots(true)) {
                 break;  // We weren't able to purge any plots
             }
         }
 
         if (pictInfo->fPlotUsage.isEmpty()) {
             fPictureHash.remove(pictInfo->fPictureID);
             delete pictInfo;
         }
     }
 
@@ skipping 12 matching lines @@
     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));
+    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->getTexture() : nullptr, 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);
@@ skipping 11 matching lines @@
         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());
+        layer->setTexture(nullptr, SkIRect::MakeEmpty(), false);
 #endif
 
     } else {
-        layer->setTexture(nullptr, SkIRect::MakeEmpty());
+        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->getTexture() : nullptr);
+        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);
@@ skipping 50 matching lines @@
         delete toBeRemoved[i];
     }
 
     GrPictureInfo* pictInfo = fPictureHash.find(pictureID);
     if (pictInfo) {
         fPictureHash.remove(pictureID);
         delete pictInfo;
     }
 }
 
-bool GrLayerCache::purgePlot() {
+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);
-        return true;
+        if (justOne) {
+            break;
+        }
     }
 
-    return false;
+    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) {
@@ skipping 28 matching lines @@
 
     plot->reset();
 }
 
 #if !GR_CACHE_HOISTED_LAYERS
 void GrLayerCache::purgeAll() {
     if (!fAtlas) {
         return;
     }
 
-    GrLayerAtlas::PlotIter iter;
-    GrLayerAtlas::Plot* plot;
-    for (plot = fAtlas->iterInit(&iter, GrLayerAtlas::kLRUFirst_IterOrder);
-         plot;
-         plot = iter.prev()) {
-        SkASSERT(0 == fPlotLocks[plot->id()]);
-
-        this->purgePlot(plot);
-    }
+    this->purgePlots(false); // clear them all out
 
     SkASSERT(0 == fPictureHash.count());
 
-    SkAutoTUnref<GrDrawContext> drawContext(
-                                fContext->drawContext(fAtlas->getTexture()->asRenderTarget()));
+    if (fAtlas->getTextureOrNull()) {
+        SkAutoTUnref<GrDrawContext> drawContext(
+                                    fContext->drawContext(fAtlas->getTexture()->asRenderTarget()));
 
-    if (drawContext) {
-        drawContext->discard();
+        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->getTexture();
+        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