commit 2a1208017dd676f94a53bbb228197c3978dbdd8a
author scroggo <scroggo@google.com> Wed Oct 22 12:07:00 2014 -0700
committer Commit bot <commit-bot@chromium.org> Wed Oct 22 12:07:00 2014 -0700
tree c19f32da3e4187f459e526f13aab58cc24d8aa7d
parent 7a2df0c672d05301362b5ad13e01bfc62871200a

Qualify the return value of SkImageDecoder::decode

Add a new enum to differentiate between a complete decode and a
partial decode (with the third value being failure). Return this
value from SkImageDecoder::onDecode (in all subclasses, plus
SkImageDecoder_empty) and ::decode.

For convenience, if the enum is treated as a boolean, success and
partial success are both considered true.

Note that the static helper functions (DecodeFile etc) still return
true and false (for one thing, this allows us to continue to use
SkImageDecoder::DecodeMemory as an SkPicture::InstallPixelRefProc in
SkPicture::CreateFromStream).

Also correctly report failure in SkASTCImageDecoder::onDecode when
SkTextureCompressor::DecompressBufferFromFormat fails.

BUG=skia:3037
BUG:b/17419670

Review URL: https://codereview.chromium.org/647023006

src/images/SkImageDecoder_libbmp.cpp

diff --git a/src/images/SkImageDecoder_libbmp.cpp b/src/images/SkImageDecoder_libbmp.cpp
index 7b87e40..af868e3 100644
--- a/src/images/SkImageDecoder_libbmp.cpp
+++ b/src/images/SkImageDecoder_libbmp.cpp
@@ -24,7 +24,7 @@
     }
 
 protected:
-    virtual bool onDecode(SkStream* stream, SkBitmap* bm, Mode mode) SK_OVERRIDE;
+    virtual Result onDecode(SkStream* stream, SkBitmap* bm, Mode mode) SK_OVERRIDE;
 
 private:
     typedef SkImageDecoder INHERITED;
@@ -92,7 +92,7 @@
     bool fJustBounds;
 };
 
-bool SkBMPImageDecoder::onDecode(SkStream* stream, SkBitmap* bm, Mode mode) {
+SkImageDecoder::Result SkBMPImageDecoder::onDecode(SkStream* stream, SkBitmap* bm, Mode mode) {
     // First read the entire stream, so that all of the data can be passed to
     // the BmpDecoderHelper.
 
@@ -101,7 +101,7 @@
     // Byte length of all of the data.
     const size_t length = SkCopyStreamToStorage(&storage, stream);
     if (0 == length) {
-        return 0;
+        return kFailure;
     }
 
     const bool justBounds = SkImageDecoder::kDecodeBounds_Mode == mode;
@@ -113,7 +113,7 @@
         const int max_pixels = 16383*16383; // max width*height
         if (!helper.DecodeImage((const char*)storage.get(), length,
                                 max_pixels, &callback)) {
-            return false;
+            return kFailure;
         }
     }
 
@@ -136,17 +136,17 @@
                                   colorType, kOpaque_SkAlphaType));
 
     if (justBounds) {
-        return true;
+        return kSuccess;
     }
 
     if (!this->allocPixelRef(bm, NULL)) {
-        return false;
+        return kFailure;
     }
 
     SkAutoLockPixels alp(*bm);
 
     if (!sampler.begin(bm, SkScaledBitmapSampler::kRGB, *this)) {
-        return false;
+        return kFailure;
     }
 
     const int srcRowBytes = width * 3;
@@ -158,5 +158,5 @@
         sampler.next(srcRow);
         srcRow += sampler.srcDY() * srcRowBytes;
     }
-    return true;
+    return kSuccess;
 }