Create a scanline decoder without creating a codec

dm/DMSrcSink.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 "DMSrcSink.h"
 #include "SamplePipeControllers.h"
 #include "SkCodec.h"
@@ skipping 141 matching lines @@
                 case SkCodec::kInvalidConversion:
                     return Error::Nonfatal("Incompatible colortype conversion");
                 default:
                     // Everything else is considered a failure.
                     return SkStringPrintf("Couldn't getPixels %s.", fPath.c_str());
             }
             canvas->drawBitmap(bitmap, 0, 0);
             break;
         }
         case kScanline_Mode: {
-            SkAutoTDelete<SkScanlineDecoder> scanlineDecoder(codec->getScanlineDecoder(
-                    decodeInfo, NULL, colorPtr, colorCountPtr));
-            if (NULL == scanlineDecoder) {
+            SkAutoTDelete<SkScanlineDecoder> scanlineDecoder(
+                    SkScanlineDecoder::NewFromData(encoded));
+            if (NULL == scanlineDecoder || SkCodec::kSuccess !=
+                    scanlineDecoder->start(decodeInfo, NULL, colorPtr, colorCountPtr)) {
                 return Error::Nonfatal("Cannot use scanline decoder for all images");
             }
+
             const SkCodec::Result result = scanlineDecoder->getScanlines(
                     bitmap.getAddr(0, 0), decodeInfo.height(), bitmap.rowBytes());
             switch (result) {
                 case SkCodec::kSuccess:
                 case SkCodec::kIncompleteInput:
                     break;
                 default:
                     return SkStringPrintf("%s failed with error message %d",
                                           fPath.c_str(), (int) result);
             }
@@ skipping 38 matching lines @@
                 const int currentSubsetWidth = (col + 1 == divisor) ?
                         subsetWidth + extraX : subsetWidth;
                 const int x = col * subsetWidth;
                 for (int row = 0; row < divisor; row++) {
                     //currentSubsetHeight may be larger than subsetHeight for bottom subsets
                     const int currentSubsetHeight = (row + 1 == divisor) ?
                             subsetHeight + extraY : subsetHeight;
                     const int y = row * subsetHeight;
                     //create scanline decoder for each subset
                     SkAutoTDelete<SkScanlineDecoder> subsetScanlineDecoder(
-                            codec->getScanlineDecoder(decodeInfo, NULL, colorPtr, colorCountPtr));
-                    if (NULL == subsetScanlineDecoder) {
+                            SkScanlineDecoder::NewFromData(encoded));
+                    if (NULL == subsetScanlineDecoder || SkCodec::kSuccess !=
+                            subsetScanlineDecoder->start(
+                            decodeInfo, NULL, colorPtr, colorCountPtr))
+                    {
                         if (x == 0 && y == 0) {
                             //first try, image may not be compatible
                             return Error::Nonfatal("Cannot use scanline decoder for all images");
                         } else {
                             return "Error scanline decoder is NULL";
                         }
                     }
                     //skip to first line of subset
                     const SkCodec::Result skipResult =
                             subsetScanlineDecoder->skipScanlines(y);
@@ skipping 45 matching lines @@
             break;
         }
         case kStripe_Mode: {
             const int height = decodeInfo.height();
             // This value is chosen arbitrarily.  We exercise more cases by choosing a value that
             // does not align with image blocks.
             const int stripeHeight = 37;
             const int numStripes = (height + stripeHeight - 1) / stripeHeight;
 
             // Decode odd stripes
-            SkAutoTDelete<SkScanlineDecoder> decoder(
-                    codec->getScanlineDecoder(decodeInfo, NULL, colorPtr, colorCountPtr));
-            if (NULL == decoder) {
+            SkAutoTDelete<SkScanlineDecoder> decoder(SkScanlineDecoder::NewFromData(encoded));
+            if (NULL == decoder || SkCodec::kSuccess !=
+                    decoder->start(decodeInfo, NULL, colorPtr, colorCountPtr)) {
                 return Error::Nonfatal("Cannot use scanline decoder for all images");
             }
             for (int i = 0; i < numStripes; i += 2) {
                 // Skip a stripe
                 const int linesToSkip = SkTMin(stripeHeight, height - i * stripeHeight);
                 SkCodec::Result result = decoder->skipScanlines(linesToSkip);
                 switch (result) {
                     case SkCodec::kSuccess:
                     case SkCodec::kIncompleteInput:
                         break;
@@ skipping 11 matching lines @@
                         case SkCodec::kSuccess:
                         case SkCodec::kIncompleteInput:
                             break;
                         default:
                             return SkStringPrintf("Cannot get scanlines for %s.", fPath.c_str());
                     }
                 }
             }
 
             // Decode even stripes
-            decoder.reset(codec->getScanlineDecoder(decodeInfo, NULL, colorPtr, colorCountPtr));
-            if (NULL == decoder) {
-                return "Failed to create second scanline decoder.";
+            const SkCodec::Result startResult = decoder->start(decodeInfo, NULL, colorPtr,
+                                                               colorCountPtr);
+            if (SkCodec::kSuccess != startResult) {
+                return "Failed to restart scanline decoder with same parameters.";
             }
             for (int i = 0; i < numStripes; i += 2) {
                 // Read a stripe
                 const int startY = i * stripeHeight;
                 const int linesToRead = SkTMin(stripeHeight, height - startY);
                 SkCodec::Result result = decoder->getScanlines(bitmap.getAddr(0, startY),
                         linesToRead, bitmap.rowBytes());
                 switch (result) {
                     case SkCodec::kSuccess:
                     case SkCodec::kIncompleteInput:
@@ skipping 730 matching lines @@
             skr.visit<void>(i, drawsAsSingletonPictures);
         }
         SkAutoTUnref<SkPicture> macroPic(macroRec.endRecordingAsPicture());
 
         canvas->drawPicture(macroPic);
         return "";
     });
 }
 
 }  // namespace DM