Return NULL when building empty LayerRasterizer.

src/effects/SkLayerRasterizer.cpp

 
 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #include "SkLayerRasterizer.h"
@@ skipping 196 matching lines @@
 void SkLayerRasterizer::Builder::addLayer(const SkPaint& paint, SkScalar dx,
                                           SkScalar dy) {
     SkASSERT(fLayers);
     SkLayerRasterizer_Rec* rec = (SkLayerRasterizer_Rec*)fLayers->push_back();
 
     SkNEW_PLACEMENT_ARGS(&rec->fPaint, SkPaint, (paint));
     rec->fOffset.set(dx, dy);
 }
 
 SkLayerRasterizer* SkLayerRasterizer::Builder::detachRasterizer() {
-    SkLayerRasterizer* rasterizer = SkNEW_ARGS(SkLayerRasterizer, (fLayers));
+    SkLayerRasterizer* rasterizer;
+    if (0 == fLayers->count()) {
+        rasterizer = NULL;
+        SkDELETE(fLayers);
+    } else {
+        rasterizer = SkNEW_ARGS(SkLayerRasterizer, (fLayers));
+    }
     fLayers = NULL;
     return rasterizer;
 }
 
 SkLayerRasterizer* SkLayerRasterizer::Builder::snapshotRasterizer() const {
+    if (0 == fLayers->count()) {
+        return NULL;
+    }
     SkDeque* layers = SkNEW_ARGS(SkDeque, (sizeof(SkLayerRasterizer_Rec), fLayers->count()));
     SkDeque::F2BIter                iter(*fLayers);
     const SkLayerRasterizer_Rec*    recOrig;
     SkDEBUGCODE(int                 count = 0;)
     while ((recOrig = static_cast<SkLayerRasterizer_Rec*>(iter.next())) != NULL) {
         SkDEBUGCODE(count++);
         SkLayerRasterizer_Rec* recCopy = static_cast<SkLayerRasterizer_Rec*>(layers->push_back());
         SkNEW_PLACEMENT_ARGS(&recCopy->fPaint, SkPaint, (recOrig->fPaint));
         recCopy->fOffset = recOrig->fOffset;
     }
     SkASSERT(fLayers->count() == count);
     SkASSERT(layers->count() == count);
     SkLayerRasterizer* rasterizer = SkNEW_ARGS(SkLayerRasterizer, (layers));
     return rasterizer;
 }