Fixing memory leak in ico decoder

src/codec/SkCodec_libico.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_libbmp.h"
 #include "SkCodec_libico.h"
 #include "SkCodec_libpng.h"
@@ skipping 15 matching lines @@
             (!memcmp(buffer, icoSig, sizeof(icoSig)) ||
             !memcmp(buffer, curSig, sizeof(curSig)));
 }
 
 /*
  * Assumes IsIco was called and returned true
  * Creates an Ico decoder
  * Reads enough of the stream to determine the image format
  */
 SkCodec* SkIcoCodec::NewFromStream(SkStream* stream) {
+    // Ensure that we do not leak the input stream
+    SkAutoTDelete<SkStream> inputStream(stream);
+
     // Header size constants
     static const uint32_t kIcoDirectoryBytes = 6;
     static const uint32_t kIcoDirEntryBytes = 16;
 
     // Read the directory header
     SkAutoTDeleteArray<uint8_t> dirBuffer(
             SkNEW_ARRAY(uint8_t, kIcoDirectoryBytes));
-    if (stream->read(dirBuffer.get(), kIcoDirectoryBytes) !=
+    if (inputStream.get()->read(dirBuffer.get(), kIcoDirectoryBytes) !=
             kIcoDirectoryBytes) {
         SkDebugf("Error: unable to read ico directory header.\n");
         return NULL;
     }
 
     // Process the directory header
     const uint16_t numImages = get_short(dirBuffer.get(), 4);
     if (0 == numImages) {
         SkDebugf("Error: No images embedded in ico.\n");
         return NULL;
     }
 
     // Ensure that we can read all of indicated directory entries
     SkAutoTDeleteArray<uint8_t> entryBuffer(
             SkNEW_ARRAY(uint8_t, numImages*kIcoDirEntryBytes));
-    if (stream->read(entryBuffer.get(), numImages*kIcoDirEntryBytes) !=
+    if (inputStream.get()->read(entryBuffer.get(), numImages*kIcoDirEntryBytes) !=
             numImages*kIcoDirEntryBytes) {
         SkDebugf("Error: unable to read ico directory entries.\n");
         return NULL;
     }
 
     // This structure is used to represent the vital information about entries
     // in the directory header.  We will obtain this information for each
     // directory entry.
     struct Entry {
         uint32_t offset;
@@ skipping 44 matching lines @@
         uint32_t size = directoryEntries.get()[i].size;
         
         // Ensure that the offset is valid
         if (offset < bytesRead) {
             SkDebugf("Warning: invalid ico offset.\n");
             continue;
         }
 
         // If we cannot skip, assume we have reached the end of the stream and
         // stop trying to make codecs
-        if (stream->skip(offset - bytesRead) != offset - bytesRead) {
+        if (inputStream.get()->skip(offset - bytesRead) != offset - bytesRead) {
             SkDebugf("Warning: could not skip to ico offset.\n");
             break;
         }
         bytesRead = offset;
 
         // Create a new stream for the embedded codec
-        SkAutoTUnref<SkData> data(SkData::NewFromStream(stream, size));
+        SkAutoTUnref<SkData> data(
+                SkData::NewFromStream(inputStream.get(), size));
         if (NULL == data.get()) {
             SkDebugf("Warning: could not create embedded stream.\n");
             break;
         }
         SkAutoTDelete<SkMemoryStream>
                 embeddedStream(SkNEW_ARGS(SkMemoryStream, (data.get())));
         bytesRead += size;
 
         // Check if the embedded codec is bmp or png and create the codec
         const bool isPng = SkPngCodec::IsPng(embeddedStream);
@@ skipping 103 matching lines @@
             }
 
             // On success or partial success, return the result
             return result;
         }
     }
 
     SkDebugf("Error: No matching candidate image in ico.\n");
     return result;
 }