Creating a new wrapper for gif decoder

src/codec/SkCodec.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkCodec.h"
 #include "SkData.h"
 #include "SkCodec_libbmp.h"
+#include "SkCodec_libgif.h"
 #include "SkCodec_libico.h"
 #include "SkCodec_libpng.h"
 #include "SkCodec_wbmp.h"
+#include "SkCodecPriv.h"
 #include "SkStream.h"
 
 struct DecoderProc {
     bool (*IsFormat)(SkStream*);
     SkCodec* (*NewFromStream)(SkStream*);
 };
 
 static const DecoderProc gDecoderProcs[] = {
     { SkPngCodec::IsPng, SkPngCodec::NewFromStream },
+    { SkGifCodec::IsGif, SkGifCodec::NewFromStream },
     { SkIcoCodec::IsIco, SkIcoCodec::NewFromStream },
     { SkBmpCodec::IsBmp, SkBmpCodec::NewFromStream },
     { SkWbmpCodec::IsWbmp, SkWbmpCodec::NewFromStream }
 };
 
 SkCodec* SkCodec::NewFromStream(SkStream* stream) {
     if (!stream) {
         return NULL;
     }
+    
+    SkCodec* codec = NULL;
     for (uint32_t i = 0; i < SK_ARRAY_COUNT(gDecoderProcs); i++) {
         DecoderProc proc = gDecoderProcs[i];
         const bool correctFormat = proc.IsFormat(stream);
         if (!stream->rewind()) {
             return NULL;
         }
         if (correctFormat) {
-            return proc.NewFromStream(stream);
+            codec = proc.NewFromStream(stream);
+            break;
         }
     }
-    return NULL;
+
+    // Set the max size at 128 megapixels (512 MB for kN32).
+    // This is about 4x smaller than a test image that takes a few minutes for
+    // dm to decode and draw.
+    const int32_t maxSize = 1 << 27;
+    if (codec != NULL &&
+            codec->getInfo().width() * codec->getInfo().height() > maxSize) {
+        SkCodecPrintf("Error: Image size too large, cannot decode.\n");
+        return NULL;
+    } else {
+        return codec;
+    }
 }
 
 SkCodec* SkCodec::NewFromData(SkData* data) {
     if (!data) {
         return NULL;
     }
     return NewFromStream(SkNEW_ARGS(SkMemoryStream, (data)));
 }
 
 SkCodec::SkCodec(const SkImageInfo& info, SkStream* stream)
@@ skipping 18 matching lines @@
 }
 
 SkScanlineDecoder* SkCodec::getScanlineDecoder(const SkImageInfo& dstInfo) {
     fScanlineDecoder.reset(NULL);
     if (!rewindIfNeeded()) {
         return NULL;
     }
     fScanlineDecoder.reset(this->onGetScanlineDecoder(dstInfo));
     return fScanlineDecoder.get();
 }