Limit lifetime of GrDrawContext objects

src/effects/SkGpuBlurUtils.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkGpuBlurUtils.h"
 
 #include "SkRect.h"
@@ skipping 178 matching lines @@
         tempTexture = srcTexture;
     } else {
         temp2.reset(context->textureProvider()->createApproxTexture(desc));
         tempTexture = temp2.get();
     }
 
     if (nullptr == dstTexture || nullptr == tempTexture) {
         return nullptr;
     }
 
-    GrDrawContext* srcDrawContext = nullptr;
+    SkAutoTUnref<GrDrawContext> srcDrawContext;
 
     for (int i = 1; i < scaleFactorX || i < scaleFactorY; i *= 2) {
         GrPaint paint;
         SkMatrix matrix;
         matrix.setIDiv(srcTexture->width(), srcTexture->height());
         SkRect dstRect(srcRect);
         if (cropToRect && i == 1) {
             dstRect.offset(-dstRect.fLeft, -dstRect.fTop);
             SkRect domain;
             matrix.mapRect(&domain, rect);
             domain.inset(i < scaleFactorX ? SK_ScalarHalf / srcTexture->width() : 0.0f,
                          i < scaleFactorY ? SK_ScalarHalf / srcTexture->height() : 0.0f);
             SkAutoTUnref<GrFragmentProcessor> fp(   GrTextureDomainEffect::Create(
                 paint.getProcessorDataManager(),
                 srcTexture,
                 matrix,
                 domain,
                 GrTextureDomain::kDecal_Mode,
                 GrTextureParams::kBilerp_FilterMode));
             paint.addColorFragmentProcessor(fp);
         } else {
             GrTextureParams params(SkShader::kClamp_TileMode, GrTextureParams::kBilerp_FilterMode);
             paint.addColorTextureProcessor(srcTexture, matrix, params);
         }
         scale_rect(&dstRect, i < scaleFactorX ? 0.5f : 1.0f,
                              i < scaleFactorY ? 0.5f : 1.0f);
 
-        GrDrawContext* dstDrawContext = context->drawContext();
+        SkAutoTUnref<GrDrawContext> dstDrawContext(context->drawContext());
         if (!dstDrawContext) {
             return nullptr;
         }
         dstDrawContext->drawNonAARectToRect(dstTexture->asRenderTarget(), clip, paint,
                                             SkMatrix::I(), dstRect, srcRect);
 
-        srcDrawContext = dstDrawContext;
+        srcDrawContext.swap(&dstDrawContext);
         srcRect = dstRect;
         srcTexture = dstTexture;
         SkTSwap(dstTexture, tempTexture);
     }
 
     const SkIRect srcIRect = srcRect.roundOut();
 
     // For really small blurs (certainly no wider than 5x5 on desktop gpus) it is faster to just
     // launch a single non separable kernel vs two launches
     if (sigmaX > 0.0f && sigmaY > 0.0f &&
             (2 * radiusX + 1) * (2 * radiusY + 1) <= MAX_KERNEL_SIZE) {
         // We shouldn't be scaling because this is a small size blur
         SkASSERT((1 == scaleFactorX) && (1 == scaleFactorY));
         SkRect dstRect = SkRect::MakeWH(srcRect.width(), srcRect.height());
 
-        GrDrawContext* dstDrawContext = context->drawContext();
+        SkAutoTUnref<GrDrawContext> dstDrawContext(context->drawContext());
         if (!dstDrawContext) {
             return nullptr;
         }
         convolve_gaussian_2d(dstDrawContext, dstTexture->asRenderTarget(), clip, srcRect, dstRect,
                              srcTexture, radiusX, radiusY, sigmaX, sigmaY, cropToRect, srcIRect);
 
-        srcDrawContext = dstDrawContext;
+        srcDrawContext.swap(&dstDrawContext);
         srcRect = dstRect;
         srcTexture = dstTexture;
         SkTSwap(dstTexture, tempTexture);
 
     } else {
         if (sigmaX > 0.0f) {
             if (scaleFactorX > 1) {
                 // TODO: if we pass in the source draw context we don't need this here
                 if (!srcDrawContext) {
-                    srcDrawContext = context->drawContext();
+                    srcDrawContext.reset(context->drawContext());
                     if (!srcDrawContext) {
                         return nullptr;
                     }        
                 }
 
                 // Clear out a radius to the right of the srcRect to prevent the
                 // X convolution from reading garbage.
                 clearRect = SkIRect::MakeXYWH(srcIRect.fRight, srcIRect.fTop,
                                               radiusX, srcIRect.height());
                 srcDrawContext->clear(srcTexture->asRenderTarget(), &clearRect, 0x0, false);
             }
             SkRect dstRect = SkRect::MakeWH(srcRect.width(), srcRect.height());
 
-            GrDrawContext* dstDrawContext = context->drawContext();
+            SkAutoTUnref<GrDrawContext> dstDrawContext(context->drawContext());
             if (!dstDrawContext) {
                 return nullptr;
             }
             convolve_gaussian(dstDrawContext, dstTexture->asRenderTarget(), clip, srcRect, dstRect,
                               srcTexture, Gr1DKernelEffect::kX_Direction, radiusX, sigmaX,
                               cropToRect);
 
-            srcDrawContext = dstDrawContext;
+            srcDrawContext.swap(&dstDrawContext);
             srcTexture = dstTexture;
             srcRect = dstRect;
             SkTSwap(dstTexture, tempTexture);
         }
 
         if (sigmaY > 0.0f) {
             if (scaleFactorY > 1 || sigmaX > 0.0f) {
                 // TODO: if we pass in the source draw context we don't need this here
                 if (!srcDrawContext) {
-                    srcDrawContext = context->drawContext();
+                    srcDrawContext.reset(context->drawContext());
                     if (!srcDrawContext) {
                         return nullptr;
                     }        
                 }
 
                 // Clear out a radius below the srcRect to prevent the Y
                 // convolution from reading garbage.
                 clearRect = SkIRect::MakeXYWH(srcIRect.fLeft, srcIRect.fBottom,
                                               srcIRect.width(), radiusY);
                 srcDrawContext->clear(srcTexture->asRenderTarget(), &clearRect, 0x0, false);
             }
 
             SkRect dstRect = SkRect::MakeWH(srcRect.width(), srcRect.height());
 
-            GrDrawContext* dstDrawContext = context->drawContext();
+            SkAutoTUnref<GrDrawContext> dstDrawContext(context->drawContext());
             if (!dstDrawContext) {
                 return nullptr;
             }
             convolve_gaussian(dstDrawContext, dstTexture->asRenderTarget(), clip, srcRect,
                               dstRect, srcTexture, Gr1DKernelEffect::kY_Direction, radiusY, sigmaY,
                               cropToRect);
 
-            srcDrawContext = dstDrawContext;
+            srcDrawContext.swap(&dstDrawContext);
             srcTexture = dstTexture;
             srcRect = dstRect;
             SkTSwap(dstTexture, tempTexture);
         }
     }
 
     if (scaleFactorX > 1 || scaleFactorY > 1) {
         SkASSERT(srcDrawContext);
 
         // Clear one pixel to the right and below, to accommodate bilinear
         // upsampling.
         clearRect = SkIRect::MakeXYWH(srcIRect.fLeft, srcIRect.fBottom,
                                       srcIRect.width() + 1, 1);
         srcDrawContext->clear(srcTexture->asRenderTarget(), &clearRect, 0x0, false);
         clearRect = SkIRect::MakeXYWH(srcIRect.fRight, srcIRect.fTop,
                                       1, srcIRect.height());
         srcDrawContext->clear(srcTexture->asRenderTarget(), &clearRect, 0x0, false);
         SkMatrix matrix;
         matrix.setIDiv(srcTexture->width(), srcTexture->height());
 
         GrPaint paint;
         // FIXME:  this should be mitchell, not bilinear.
         GrTextureParams params(SkShader::kClamp_TileMode, GrTextureParams::kBilerp_FilterMode);
         paint.addColorTextureProcessor(srcTexture, matrix, params);
 
         SkRect dstRect(srcRect);
         scale_rect(&dstRect, (float) scaleFactorX, (float) scaleFactorY);
 
-        GrDrawContext* dstDrawContext = context->drawContext();
+        SkAutoTUnref<GrDrawContext> dstDrawContext(context->drawContext());
         if (!dstDrawContext) {
             return nullptr;
         }
         dstDrawContext->drawNonAARectToRect(dstTexture->asRenderTarget(), clip, paint,
                                             SkMatrix::I(), dstRect, srcRect);
 
-        srcDrawContext = dstDrawContext;
+        srcDrawContext.swap(&dstDrawContext);
         srcRect = dstRect;
         srcTexture = dstTexture;
         SkTSwap(dstTexture, tempTexture);
     }
 
     return SkRef(srcTexture);
 }
 #endif
 
 }