Destroy SkScanlineDecoder in the SkCodec subclass destructors

src/codec/SkJpegCodec.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 "SkJpegCodec.h"
 #include "SkJpegDecoderMgr.h"
@@ skipping 279 matching lines @@
     fSrcRowBytes = SkSwizzler::BytesPerPixel(srcConfig) * dstInfo.width();
 }
 
 /*
  * Performs the jpeg decode
  */
 SkCodec::Result SkJpegCodec::onGetPixels(const SkImageInfo& dstInfo,
                                          void* dst, size_t dstRowBytes,
                                          const Options& options, SkPMColor*, int*) {
 
+    // Do not allow a regular decode if the caller has asked for a scanline decoder
+    if (NULL != this->scanlineDecoder()) {
+        return fDecoderMgr->returnFailure("cannot getPixels() if a scanline decoder has been"
+                "created", kInvalidInput);
+    }
+
     // Rewind the stream if needed
     if (!this->handleRewind()) {
-        fDecoderMgr->returnFailure("could not rewind stream", kCouldNotRewind);
+        return fDecoderMgr->returnFailure("could not rewind stream", kCouldNotRewind);
     }
 
     // Get a pointer to the decompress info since we will use it quite frequently
     jpeg_decompress_struct* dinfo = fDecoderMgr->dinfo();
 
     // Set the jump location for libjpeg errors
     if (setjmp(fDecoderMgr->getJmpBuf())) {
         return fDecoderMgr->returnFailure("setjmp", kInvalidInput);
     }
 
@@ skipping 129 matching lines @@
 
         return SkImageGenerator::kSuccess;
     }
 
     void onFinish() override {
         if (setjmp(fCodec->fDecoderMgr->getJmpBuf())) {
             SkCodecPrintf("setjmp: Error in libjpeg finish_decompress\n");
             return;
         }
 
+        // We may not have decoded the entire image.  Prevent libjpeg-turbo from failing on a
+        // partial decode.
+        fCodec->fDecoderMgr->dinfo()->output_scanline = dstInfo().height();
         jpeg_finish_decompress(fCodec->fDecoderMgr->dinfo());
     }
 
 private:
     SkJpegCodec*        fCodec;     // unowned
     SkAutoMalloc        fStorage;
     uint8_t*            fSrcRow;    // ptr into fStorage
 
     typedef SkScanlineDecoder INHERITED;
 };
@@ skipping 34 matching lines @@
     // Create the swizzler
     this->initializeSwizzler(dstInfo, NULL, dstInfo.minRowBytes(), options);
     if (NULL == fSwizzler) {
         SkCodecPrintf("Could not create swizzler\n");
         return NULL;
     }
 
     // Return the new scanline decoder
     return SkNEW_ARGS(SkJpegScanlineDecoder, (dstInfo, this));
 }