WIP RasterCanvasLayerAllocator

src/core/SkCanvas.cpp

Index: src/core/SkCanvas.cpp
diff --git a/src/core/SkCanvas.cpp b/src/core/SkCanvas.cpp
index f7f870210d0844b6347030575ec159d210f15ea9..989903406adf4a11a832da84eeca436f64b0fc0f 100644
--- a/src/core/SkCanvas.cpp
+++ b/src/core/SkCanvas.cpp
@@ -24,6 +24,7 @@
 #include "SkPaintPriv.h"
 #include "SkPatchUtils.h"
 #include "SkPicture.h"
+#include "SkRasterCanvasLayerAllocator.h"
 #include "SkRasterClip.h"
 #include "SkReadPixelsRec.h"
 #include "SkRRect.h"
@@ -195,6 +196,8 @@ struct DeviceCM {
     SkRasterClip        fClip;
     SkPaint*            fPaint; // may be null (in the future)
     const SkMatrix*     fMatrix;
+    SkRasterCanvasLayerAllocator* fAllocator;
+    void*               fNativeContext;
     SkMatrix            fMatrixStorage;
     const bool          fDeviceIsBitmapDevice;
 
@@ -202,6 +205,8 @@ struct DeviceCM {
              bool conservativeRasterClip, bool deviceIsBitmapDevice)
         : fNext(nullptr)
         , fClip(conservativeRasterClip)
+        , fAllocator(nullptr)
+        , fNativeContext(nullptr)
         , fDeviceIsBitmapDevice(deviceIsBitmapDevice)
     {
         if (nullptr != device) {
@@ -214,6 +219,10 @@ struct DeviceCM {
 
     ~DeviceCM() {
         if (fDevice) {
+            if (fAllocator) {
+                fAllocator->free(fDevice->accessBitmap(false).getPixels(),

[reed1, 2016/05/11 18:58:24]

Do we need to pass the actual pixel addr to the free method, and not just the
nativecontext?

[tomhudson, 2016/05/26 16:36:17]

I'd assumed that allocators would have to map from buffer -> native context
(which means really I only need the actual pixel addr here); that would also
require storing the reverse mapping from native context -> buffer.

My unit test doesn't touch that; I think we won't have a well-grounded sense of
how important it is until we port Chrome to this, and we need to solve
lifecycle/construction issues first.

+                                 fNativeContext);
+            }
             fDevice->onDetachFromCanvas();
             fDevice->unref();
         }
@@ -669,6 +678,7 @@ SkBaseDevice* SkCanvas::init(SkBaseDevice* device, InitFlags flags) {
     fMCRec->fTopLayer = fMCRec->fLayer;
 
     fSurfaceBase = nullptr;
+    fAllocator = nullptr;
 
     if (device) {
         // The root device and the canvas should always have the same pixel geometry
@@ -1237,7 +1247,7 @@ void SkCanvas::internalSaveLayer(const SaveLayerRec& rec, SaveLayerStrategy stra
         const SkBaseDevice::TileUsage usage = SkBaseDevice::kNever_TileUsage;
         const SkBaseDevice::CreateInfo createInfo = SkBaseDevice::CreateInfo(info, usage, geo,
                                                                             preserveLCDText, false);
-        SkBaseDevice* newDev = device->onCreateDevice(createInfo, paint);
+        SkBaseDevice* newDev = device->onCreateDevice(createInfo, paint, fAllocator);
         if (nullptr == newDev) {
             // If onCreateDevice didn't succeed, try raster (e.g. PDF couldn't handle the paint)
             const SkSurfaceProps surfaceProps(fProps.flags(), createInfo.fPixelGeometry);
@@ -1262,6 +1272,10 @@ void SkCanvas::internalSaveLayer(const SaveLayerRec& rec, SaveLayerStrategy stra
     device->unref();
 
     layer->fNext = fMCRec->fTopLayer;
+    layer->fAllocator = fAllocator;
+    layer->fNativeContext = fAllocator
+        ? fAllocator->getNativeContext(device->accessBitmap(false).getPixels())
+        : nullptr;
     fMCRec->fLayer = layer;
     fMCRec->fTopLayer = layer;    // this field is NOT an owner of layer
 }
@@ -1286,6 +1300,7 @@ void SkCanvas::internalRestore() {
 
     // reserve our layer (if any)
     DeviceCM* layer = fMCRec->fLayer;   // may be null
+
     // now detach it from fMCRec so we can pop(). Gets freed after its drawn
     fMCRec->fLayer = nullptr;
 
@@ -1299,6 +1314,7 @@ void SkCanvas::internalRestore() {
         recorder will have already recorded the restore).
     */
     if (layer) {
+        SkASSERT(layer->fAllocator == fAllocator);
         if (layer->fNext) {
             const SkIPoint& origin = layer->fDevice->getOrigin();
             this->internalDrawDevice(layer->fDevice, origin.x(), origin.y(),
@@ -1737,6 +1753,11 @@ void SkCanvas::replayClips(ClipVisitor* visitor) const {
     }
 }
 
+void* SkCanvas::getTopLayerNative() const {
+    return fMCRec->fLayer->fNativeContext;
+}
+
+
 ///////////////////////////////////////////////////////////////////////////////
 
 bool SkCanvas::isClipEmpty() const {