lock special-raster while the caller's bitmap is in-scope

src/core/SkSpecialImage.cpp

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file
  */
 
 #include "SkSpecialImage.h"
 #include "SkBitmap.h"
 #include "SkImage.h"
@@ skipping 191 matching lines @@
     }
     return nullptr;
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 
 class SkSpecialImage_Raster : public SkSpecialImage_Base {
 public:
     SkSpecialImage_Raster(const SkIRect& subset, const SkBitmap& bm, const SkSurfaceProps* props)
         : INHERITED(subset, bm.getGenerationID(), props)
-        , fBitmap(bm) {
-        if (bm.pixelRef() && bm.pixelRef()->isPreLocked()) {
-            // we only preemptively lock if there is no chance of triggering something expensive
-            // like a lazy decode or imagegenerator. PreLocked means it is flat pixels already.
-            fBitmap.lockPixels();
-        }
+        , fBitmap(bm)
+    {
+        SkASSERT(bm.pixelRef());
+
+        // We have to lock now, while bm is still in scope, since it may have come from our
+        // cache, which means we need to keep it locked until we (the special) are done, since
+        // we cannot re-generate the cache entry (if bm came from a generator).
+        fBitmap.lockPixels();
+        SkASSERT(fBitmap.getPixels());
     }
 
     bool isOpaque() const override { return fBitmap.isOpaque(); }
 
     size_t getSize() const override { return fBitmap.getSize(); }
 
     void onDraw(SkCanvas* canvas, SkScalar x, SkScalar y, const SkPaint* paint) const override {
         SkRect dst = SkRect::MakeXYWH(x, y,
                                       this->subset().width(), this->subset().height());
 
@@ skipping 57 matching lines @@
     SkBitmap fBitmap;
 
     typedef SkSpecialImage_Base INHERITED;
 };
 
 sk_sp<SkSpecialImage> SkSpecialImage::MakeFromRaster(const SkIRect& subset,
                                                      const SkBitmap& bm,
                                                      const SkSurfaceProps* props) {
     SkASSERT(rect_fits(subset, bm.width(), bm.height()));
 
+    if (!bm.pixelRef()) {
+        return nullptr;
+    }
+
     const SkBitmap* srcBM = &bm;
     SkBitmap tmpStorage;
     // ImageFilters only handle N32 at the moment, so force our src to be that
     if (!valid_for_imagefilters(bm.info())) {
         if (!bm.copyTo(&tmpStorage, kN32_SkColorType)) {
             return nullptr;
         }
         srcBM = &tmpStorage;
     }
     return sk_make_sp<SkSpecialImage_Raster>(subset, *srcBM, props);
@@ skipping 140 matching lines @@
                                                   sk_sp<GrTexture> tex,
                                                   sk_sp<SkColorSpace> colorSpace,
                                                   const SkSurfaceProps* props,
                                                   SkAlphaType at) {
     SkASSERT(rect_fits(subset, tex->width(), tex->height()));
     return sk_make_sp<SkSpecialImage_Gpu>(subset, uniqueID, std::move(tex), at,
                                           std::move(colorSpace), props);
 }
 
 #endif