Optimize CSS box-shadow performance by caching the SkMask of the blur effect.

src/effects/SkBlurMask.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 "SkBlurMask.h"
@@ skipping 523 matching lines @@
 
     if (src.fImage) {
         size_t dstSize = dst->computeImageSize();
         if (0 == dstSize) {
             return false;   // too big to allocate, abort
         }
 
         int             sw = src.fBounds.width();
         int             sh = src.fBounds.height();
         const uint8_t*  sp = src.fImage;
-        uint8_t*        dp = SkMask::AllocImage(dstSize);
-        SkAutoTCallVProc<uint8_t, SkMask_FreeImage> autoCall(dp);
+        uint8_t* dp = NULL;
+        SkDiscardableMemory* dm = NULL;
+        if (dst->fUseDiscardableMemory && (dm = SkDiscardableMemory::Create(dstSize))) {
+            dp = static_cast<uint8_t*>(dm->data());
+            dst->fDiscardableMemory = dm;
+        } else
+            dp = SkMask::AllocImage(dstSize);
 
         // build the blurry destination
         SkAutoTMalloc<uint8_t>  tmpBuffer(dstSize);
         uint8_t*                tp = tmpBuffer.get();
         int w = sw, h = sh;
 
         if (outerWeight == 255) {
             int loRadius, hiRadius;
             get_adjusted_radii(passRadius, &loRadius, &hiRadius);
             if (kHigh_SkBlurQuality == quality) {
@@ skipping 25 matching lines @@
             }
         }
 
         dst->fImage = dp;
         // if need be, alloc the "real" dst (same size as src) and copy/merge
         // the blur into it (applying the src)
         if (style == kInner_SkBlurStyle) {
             // now we allocate the "real" dst, mirror the size of src
             size_t srcSize = src.computeImageSize();
             if (0 == srcSize) {
+                if (dm) {
+                    dm->unlock();
+                    SkDELETE(dm);
+                } else if (dp) {
+                    SkMask::FreeImage(dp);
+                }
                 return false;   // too big to allocate, abort
             }
             dst->fImage = SkMask::AllocImage(srcSize);
             merge_src_with_blur(dst->fImage, src.fRowBytes,
                                 sp, src.fRowBytes,
                                 dp + passCount * (rx + ry * dst->fRowBytes),
                                 dst->fRowBytes, sw, sh);
-            SkMask::FreeImage(dp);
+            if (dm) {
+                dm->unlock();
+                SkDELETE(dm);
+            } else if (dp) {
+                SkMask::FreeImage(dp);
+            }
         } else if (style != kNormal_SkBlurStyle) {
             clamp_with_orig(dp + passCount * (rx + ry * dst->fRowBytes),
                             dst->fRowBytes, sp, src.fRowBytes, sw, sh, style);
         }
-        (void)autoCall.detach();
     }
 
     if (style == kInner_SkBlurStyle) {
         dst->fBounds = src.fBounds; // restore trimmed bounds
         dst->fRowBytes = src.fRowBytes;
     }
 
     return true;
 }
 
@@ skipping 373 matching lines @@
         (void)autoCall.detach();
     }
 
     if (style == kInner_SkBlurStyle) {
         dst->fBounds = src.fBounds; // restore trimmed bounds
         dst->fRowBytes = src.fRowBytes;
     }
 
     return true;
 }