commit 313c4635e3f1005e6807f5b0ad52805f30902d66
author Matt Sarett <msarett@google.com> Thu Oct 20 12:35:23 2016 -0400
committer Skia Commit-Bot <skia-commit-bot@chromium.org> Thu Oct 20 17:31:35 2016 +0000
tree 4e1580f7246f70fa7235982e6d17ec0461f8ad6a
parent ff6a07f4dedc67237cb26500d3617194a1ae5a9c

Safely handle unsupported color xforms in SkCodec

(1) The transformation code *should* support any src SkColorSpace
that we successfully parse.  This is agreed upon internally and
by clients.  The fact that we currently don't is just a bug...
(2) We cannot and will not support all SkColorSpaces as dsts.

So if we fail to make a SkColorSpaceXform, we should assume that
it was caused by a bad dst color space.  The correct response in
this case is to return kInvalidConversion.  I've rewritten the CL
to do this.

The fact that weird src spaces will sometimes trigger a
kInvalidConversion is just a bug that is being actively worked on.

TBR=reed@google.com

BUG=skia:

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=3661

Change-Id: Iac2b45120507ec71b1b3d555c61931f7348dad9e
Reviewed-on: https://skia-review.googlesource.com/3661
Commit-Queue: Matt Sarett <msarett@google.com>
Reviewed-by: Leon Scroggins <scroggo@google.com>
Reviewed-by: Robert Aftias <raftias@google.com>

src/codec/SkWebpCodec.cpp

diff --git a/src/codec/SkWebpCodec.cpp b/src/codec/SkWebpCodec.cpp
index 443a4a0..746e9b7 100644
--- a/src/codec/SkWebpCodec.cpp
+++ b/src/codec/SkWebpCodec.cpp
@@ -197,10 +197,8 @@
         return kInvalidConversion;
     }
 
-    std::unique_ptr<SkColorSpaceXform> colorXform = nullptr;
-    if (needs_color_xform(dstInfo, this->getInfo())) {
-        colorXform = SkColorSpaceXform::New(this->getInfo().colorSpace(), dstInfo.colorSpace());
-        SkASSERT(colorXform);
+    if (!this->initializeColorXform(dstInfo)) {
+        return kInvalidConversion;
     }
 
     WebPDecoderConfig config;
@@ -262,7 +260,7 @@
     // color transform swizzle if necessary.
     // Lossy webp is encoded as YUV (so RGBA and BGRA are the same cost).  Lossless webp is
     // encoded as BGRA. This means decoding to BGRA is either faster or the same cost as RGBA.
-    config.output.colorspace = colorXform ? MODE_BGRA :
+    config.output.colorspace = this->colorXform() ? MODE_BGRA :
             webp_decode_mode(dstInfo.colorType(), dstInfo.alphaType() == kPremul_SkAlphaType);
     config.output.is_external_memory = 1;
 
@@ -307,7 +305,7 @@
             return kInvalidInput;
     }
 
-    if (colorXform) {
+    if (this->colorXform()) {
         SkColorSpaceXform::ColorFormat dstColorFormat = select_xform_format(dstInfo.colorType());
         SkAlphaType xformAlphaType = select_xform_alpha(dstInfo.alphaType(),
                                                         this->getInfo().alphaType());
@@ -315,9 +313,9 @@
         uint32_t* src = (uint32_t*) config.output.u.RGBA.rgba;
         size_t srcRowBytes = config.output.u.RGBA.stride;
         for (int y = 0; y < rowsDecoded; y++) {
-            SkAssertResult(colorXform->apply(dstColorFormat, dst,
-                                             SkColorSpaceXform::kBGRA_8888_ColorFormat, src,
-                                             dstInfo.width(), xformAlphaType));
+            SkAssertResult(this->colorXform()->apply(dstColorFormat, dst,
+                    SkColorSpaceXform::kBGRA_8888_ColorFormat, src, dstInfo.width(),
+                    xformAlphaType));
             dst = SkTAddOffset<void>(dst, rowBytes);
             src = SkTAddOffset<uint32_t>(src, srcRowBytes);
         }