Revert of Defer saves() until they're needed

src/core/SkCanvas.cpp

Index: src/core/SkCanvas.cpp
diff --git a/src/core/SkCanvas.cpp b/src/core/SkCanvas.cpp
index 294562ad92356d78e716ee44cd0c32aa66ea0956..083a8ed7e8a8cea5ccb505b1d6a3537a8ed95fd7 100644
--- a/src/core/SkCanvas.cpp
+++ b/src/core/SkCanvas.cpp
@@ -170,6 +170,8 @@
 */
 class SkCanvas::MCRec {
 public:
+    SkRasterClip    fRasterClip;
+    SkMatrix        fMatrix;
     SkDrawFilter*   fFilter;    // the current filter (or null)
     DeviceCM*       fLayer;
     /*  If there are any layers in the stack, this points to the top-most
@@ -178,26 +180,22 @@
         reference counted, since the real owner is either our fLayer field,
         or a previous one in a lower level.)
     */
-    DeviceCM*       fTopLayer;
-    SkRasterClip    fRasterClip;
-    SkMatrix        fMatrix;
-    int             fDeferredSaveCount;
+    DeviceCM*   fTopLayer;
 
     MCRec(bool conservativeRasterClip) : fRasterClip(conservativeRasterClip) {
+        fMatrix.reset();
         fFilter     = NULL;
         fLayer      = NULL;
         fTopLayer   = NULL;
-        fMatrix.reset();
-        fDeferredSaveCount = 0;
 
         // don't bother initializing fNext
         inc_rec();
     }
-    MCRec(const MCRec& prev) : fRasterClip(prev.fRasterClip), fMatrix(prev.fMatrix) {
+    MCRec(const MCRec& prev) : fRasterClip(prev.fRasterClip) {
+        fMatrix = prev.fMatrix;
         fFilter = SkSafeRef(prev.fFilter);
         fLayer = NULL;
         fTopLayer = prev.fTopLayer;
-        fDeferredSaveCount = 0;
 
         // don't bother initializing fNext
         inc_rec();
@@ -415,7 +413,6 @@
     fAllowSoftClip = true;
     fAllowSimplifyClip = false;
     fDeviceCMDirty = true;
-    fSaveCount = 1;
     fSaveLayerCount = 0;
     fCullCount = 0;
     fMetaData = NULL;
@@ -788,54 +785,21 @@
 
 ///////////////////////////////////////////////////////////////////////////////
 
-void SkCanvas::checkForDeferredSave() {
-    if (fMCRec->fDeferredSaveCount > 0) {
-        fMCRec->fDeferredSaveCount -= 1;
-        this->doSave();
-    }
-}
-
 int SkCanvas::getSaveCount() const {
-#ifdef SK_DEBUG
-    int count = 0;
-    SkDeque::Iter iter(fMCStack, SkDeque::Iter::kFront_IterStart);
-    for (;;) {
-        const MCRec* rec = (const MCRec*)iter.next();
-        if (!rec) {
-            break;
-        }
-        count += 1 + rec->fDeferredSaveCount;
-    }
-    SkASSERT(count == fSaveCount);
-#endif
-    return fSaveCount;
+    return fMCStack.count();
 }
 
 int SkCanvas::save() {
-    fSaveCount += 1;
-    fMCRec->fDeferredSaveCount += 1;
-    return this->getSaveCount() - 1;  // return our prev value
-}
-
-void SkCanvas::doSave() {
     this->willSave();
-    this->internalSave();
+    return this->internalSave();
 }
 
 void SkCanvas::restore() {
-    if (fMCRec->fDeferredSaveCount > 0) {
-        SkASSERT(fSaveCount > 1);
-        fSaveCount -= 1;
-        fMCRec->fDeferredSaveCount -= 1;
-    } else {
-        // check for underflow
-        if (fMCStack.count() > 1) {
-            this->willRestore();
-            SkASSERT(fSaveCount > 1);
-            fSaveCount -= 1;
-            this->internalRestore();
-            this->didRestore();
-        }
+    // check for underflow
+    if (fMCStack.count() > 1) {
+        this->willRestore();
+        this->internalRestore();
+        this->didRestore();
     }
 }
 
@@ -851,12 +815,16 @@
     }
 }
 
-void SkCanvas::internalSave() {
+int SkCanvas::internalSave() {
+    int saveCount = this->getSaveCount(); // record this before the actual save
+
     MCRec* newTop = (MCRec*)fMCStack.push_back();
     new (newTop) MCRec(*fMCRec);    // balanced in restore()
     fMCRec = newTop;
 
     fClipStack.save();
+
+    return saveCount;
 }
 
 static bool bounds_affects_clip(SkCanvas::SaveFlags flags) {
@@ -913,19 +881,16 @@
 
 int SkCanvas::saveLayer(const SkRect* bounds, const SkPaint* paint) {
     SaveLayerStrategy strategy = this->willSaveLayer(bounds, paint, kARGB_ClipLayer_SaveFlag);
-    fSaveCount += 1;
-    this->internalSaveLayer(bounds, paint, kARGB_ClipLayer_SaveFlag, false, strategy);
-    return this->getSaveCount() - 1;
-}
-
-int SkCanvas::saveLayer(const SkRect* bounds, const SkPaint* paint, SaveFlags flags) {
+    return this->internalSaveLayer(bounds, paint, kARGB_ClipLayer_SaveFlag, false, strategy);
+}
+
+int SkCanvas::saveLayer(const SkRect* bounds, const SkPaint* paint,
+                        SaveFlags flags) {
     SaveLayerStrategy strategy = this->willSaveLayer(bounds, paint, flags);
-    fSaveCount += 1;
-    this->internalSaveLayer(bounds, paint, flags, false, strategy);
-    return this->getSaveCount() - 1;
-}
-
-void SkCanvas::internalSaveLayer(const SkRect* bounds, const SkPaint* paint, SaveFlags flags,
+    return this->internalSaveLayer(bounds, paint, flags, false, strategy);
+}
+
+int SkCanvas::internalSaveLayer(const SkRect* bounds, const SkPaint* paint, SaveFlags flags,
                                 bool justForImageFilter, SaveLayerStrategy strategy) {
 #ifndef SK_SUPPORT_LEGACY_CLIPTOLAYERFLAG
     flags |= kClipToLayer_SaveFlag;
@@ -933,19 +898,19 @@
 
     // do this before we create the layer. We don't call the public save() since
     // that would invoke a possibly overridden virtual
-    this->internalSave();
+    int count = this->internalSave();
 
     fDeviceCMDirty = true;
 
     SkIRect ir;
     if (!this->clipRectBounds(bounds, flags, &ir, paint ? paint->getImageFilter() : NULL)) {
-        return;
+        return count;
     }
 
     // FIXME: do willSaveLayer() overriders returning kNoLayer_SaveLayerStrategy really care about
     // the clipRectBounds() call above?
     if (kNoLayer_SaveLayerStrategy == strategy) {
-        return;
+        return count;
     }
 
     // Kill the imagefilter if our device doesn't allow it
@@ -954,7 +919,7 @@
         if (!this->getTopDevice()->allowImageFilter(paint->getImageFilter())) {
             if (justForImageFilter) {
                 // early exit if the layer was just for the imageFilter
-                return;
+                return count;
             }
             SkPaint* p = lazyP.set(*paint);
             p->setImageFilter(NULL);
@@ -969,7 +934,7 @@
     SkBaseDevice* device = this->getTopDevice();
     if (NULL == device) {
         SkDebugf("Unable to find device for layer.");
-        return;
+        return count;
     }
 
     SkBaseDevice::Usage usage = SkBaseDevice::kSaveLayer_Usage;
@@ -980,7 +945,7 @@
                                                                        fProps.pixelGeometry()));
     if (NULL == device) {
         SkDebugf("Unable to create device for layer.");
-        return;
+        return count;
     }
 
     device->setOrigin(ir.fLeft, ir.fTop);
@@ -993,6 +958,7 @@
     fMCRec->fTopLayer = layer;    // this field is NOT an owner of layer
 
     fSaveLayerCount += 1;
+    return count;
 }
 
 int SkCanvas::saveLayerAlpha(const SkRect* bounds, U8CPU alpha) {
@@ -1149,7 +1115,6 @@
 #endif
 
 void SkCanvas::pushCull(const SkRect& cullRect) {
-    this->checkForDeferredSave();
     ++fCullCount;
     this->onPushCull(cullRect);
 
@@ -1321,7 +1286,6 @@
         return;
     }
 
-    this->checkForDeferredSave();
     fDeviceCMDirty = true;
     fCachedLocalClipBoundsDirty = true;
     fMCRec->fMatrix.preConcat(matrix);
@@ -1330,7 +1294,6 @@
 }
 
 void SkCanvas::setMatrix(const SkMatrix& matrix) {
-    this->checkForDeferredSave();
     fDeviceCMDirty = true;
     fCachedLocalClipBoundsDirty = true;
     fMCRec->fMatrix = matrix;
@@ -1347,7 +1310,6 @@
 //////////////////////////////////////////////////////////////////////////////
 
 void SkCanvas::clipRect(const SkRect& rect, SkRegion::Op op, bool doAA) {
-    this->checkForDeferredSave();
     ClipEdgeStyle edgeStyle = doAA ? kSoft_ClipEdgeStyle : kHard_ClipEdgeStyle;
     this->onClipRect(rect, op, edgeStyle);
 }
@@ -1405,7 +1367,6 @@
 }
 
 void SkCanvas::clipRRect(const SkRRect& rrect, SkRegion::Op op, bool doAA) {
-    this->checkForDeferredSave();
     ClipEdgeStyle edgeStyle = doAA ? kSoft_ClipEdgeStyle : kHard_ClipEdgeStyle;
     if (rrect.isRect()) {
         this->onClipRect(rrect.getBounds(), op, edgeStyle);
@@ -1441,7 +1402,6 @@
 }
 
 void SkCanvas::clipPath(const SkPath& path, SkRegion::Op op, bool doAA) {
-    this->checkForDeferredSave();
     ClipEdgeStyle edgeStyle = doAA ? kSoft_ClipEdgeStyle : kHard_ClipEdgeStyle;
     SkRect r;
     if (!path.isInverseFillType() && path.isRect(&r)) {
@@ -1524,7 +1484,6 @@
 }
 
 void SkCanvas::clipRegion(const SkRegion& rgn, SkRegion::Op op) {
-    this->checkForDeferredSave();
     this->onClipRegion(rgn, op);
 }