Updates to skimage tool to use it for testing.

src/images/SkImageDecoder.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 "SkImageDecoder.h"
 #include "SkBitmap.h"
 #include "SkImagePriv.h"
 #include "SkPixelRef.h"
 #include "SkStream.h"
 #include "SkTemplates.h"
 #include "SkCanvas.h"
 
 SK_DEFINE_INST_COUNT(SkImageDecoder::Peeker)
 SK_DEFINE_INST_COUNT(SkImageDecoder::Chooser)
 SK_DEFINE_INST_COUNT(SkImageDecoderFactory)
 
 const char *SkImageDecoder::sFormatName[] = {

[epoger, 2013/04/19 21:35:16]

Rather than using an array to hold this lookup table, I think a switch statement
is better, for two reasons:

1. If we forget to list any of the Format enum values in the switch statement,
the compiler will issue a warning.

2. It will be easier to make sure they are listed in the same order.

[scroggo, 2013/04/19 22:12:01]

Done.

     "Unknown Format",
     "BMP",
     "GIF",
     "ICO",
     "JPEG",
     "PNG",
     "WBMP",
     "WEBP",
 };
 
@@ skipping 21 matching lines @@
     SkSafeUnref(fPeeker);
     SkSafeUnref(fChooser);
     SkSafeUnref(fAllocator);
 }
 
 SkImageDecoder::Format SkImageDecoder::getFormat() const {
     return kUnknown_Format;
 }
 
 const char* SkImageDecoder::getFormatName() const {
-    SkASSERT(SK_ARRAY_COUNT(sFormatName) == kLastKnownFormat);
+    SkASSERT(SK_ARRAY_COUNT(sFormatName) == kLastKnownFormat + 1);

[epoger, 2013/04/19 21:35:16]

It scares me that the previous error wasn't caught by a unit test.  Are there
some unit tests that can be beefed up?

[scroggo, 2013/04/19 22:12:01]

Lucky for us, no one was calling it...

Using the switch statement, this assert has been removed.

[epoger, 2013/04/23 16:03:40]

Regarding unit tests: Regardless of whether code is run as part of the Skia
library, or used as a tool to test the Skia library, I think it's good (in the
absence of counter-argument) to make sure it's tested.  Broken tools can cause
all sorts of problems.

     return sFormatName[this->getFormat()];
 }
 
 SkImageDecoder::Peeker* SkImageDecoder::setPeeker(Peeker* peeker) {
     SkRefCnt_SafeAssign(fPeeker, peeker);
     return peeker;
 }
 
 SkImageDecoder::Chooser* SkImageDecoder::setChooser(Chooser* chooser) {
     SkRefCnt_SafeAssign(fChooser, chooser);
@@ skipping 245 matching lines @@
 
     if (NULL != codec) {
         success = codec->decode(stream, bm, pref, mode);
         if (success && format) {
             *format = codec->getFormat();
         }
         delete codec;
     }
     return success;
 }