Revert of Switch SkPDFStream's internal storage from SkStream to SkData (https://codereview.chromium.org/340783013/)

Reason for revert:
Causes canary failures

Original issue's description:
> Switch SkPDFStream's internal storage from SkStream to SkData
>
> Motivation: This makes SkPDFStream thread-safe for two threads
> serializing it at once, since a SkStream has an internal position.
>
> Updated SkPDFFont, SkPDFGraphicState, and SkPDFPage's use of
> SkPDFStream to use the SkData constructor rather than the SkStream
> constructor (saving a memcpy).
>
> BUG=skia:2683
>
> Committed: https://skia.googlesource.com/skia/+/c1dfa14b645ae274780f026dd86c9b633fbdad06

R=mtklein@google.com, djsollen@google.com, halcanary@google.com
TBR=djsollen@google.com, halcanary@google.com, mtklein@google.com
NOTREECHECKS=true
NOTRY=true
BUG=skia:2683

Author: rmistry@google.com

Review URL: https://codereview.chromium.org/354043005

1 files changed, 28 insertions, 43 deletions

diff --git a/src/pdf/SkPDFFont.cpp b/src/pdf/SkPDFFont.cpp
index aa4b4b5534..014b328030 100644
--- a/src/pdf/SkPDFFont.cpp
+++ b/src/pdf/SkPDFFont.cpp
@@ -150,8 +150,8 @@ int8_t hexToBin(uint8_t c) {
     return -1;
 }
 
-static SkData* handle_type1_stream(SkStream* srcStream, size_t* headerLen,
-                                   size_t* dataLen, size_t* trailerLen) {
+SkStream* handleType1Stream(SkStream* srcStream, size_t* headerLen,
+                            size_t* dataLen, size_t* trailerLen) {
     // srcStream may be backed by a file or a unseekable fd, so we may not be
     // able to use skip(), rewind(), or getMemoryBase().  read()ing through
     // the input only once is doable, but very ugly. Furthermore, it'd be nice
@@ -199,43 +199,26 @@ static SkData* handle_type1_stream(SkStream* srcStream, size_t* headerLen,
     SkAutoDataUnref aud(data);
 
     if (parsePFB(src, srcLen, headerLen, dataLen, trailerLen)) {
-        static const int kPFBSectionHeaderLength = 6;
-        const size_t length = *headerLen + *dataLen + *trailerLen;
-        SkASSERT(length > 0);
-        SkASSERT(length + (2 * kPFBSectionHeaderLength) <= srcLen);
-
-        SkAutoTMalloc<uint8_t> buffer(length);
-
-        const uint8_t* const srcHeader = src + kPFBSectionHeaderLength;
-        // There is a six-byte section header before header and data
-        // (but not trailer) that we're not going to copy.
-        const uint8_t* const srcData
-            = srcHeader + *headerLen + kPFBSectionHeaderLength;
-        const uint8_t* const srcTrailer = srcData + *headerLen;
-
-        uint8_t* const resultHeader = buffer.get();
-        uint8_t* const resultData = resultHeader + *headerLen;
-        uint8_t* const resultTrailer = resultData + *dataLen;
-
-        SkASSERT(resultTrailer + *trailerLen == resultHeader + length);
-
-        memcpy(resultHeader,  srcHeader,  *headerLen);
-        memcpy(resultData,    srcData,    *dataLen);
-        memcpy(resultTrailer, srcTrailer, *trailerLen);
-
-        return SkData::NewFromMalloc(buffer.detach(), length);
+        SkMemoryStream* result =
+            new SkMemoryStream(*headerLen + *dataLen + *trailerLen);
+        memcpy((char*)result->getAtPos(), src + 6, *headerLen);
+        result->seek(*headerLen);
+        memcpy((char*)result->getAtPos(), src + 6 + *headerLen + 6, *dataLen);
+        result->seek(*headerLen + *dataLen);
+        memcpy((char*)result->getAtPos(), src + 6 + *headerLen + 6 + *dataLen,
+               *trailerLen);
+        result->rewind();
+        return result;
     }
 
     // A PFA has to be converted for PDF.
     size_t hexDataLen;
     if (parsePFA((const char*)src, srcLen, headerLen, &hexDataLen, dataLen,
                  trailerLen)) {
-        const size_t length = *headerLen + *dataLen + *trailerLen;
-        SkASSERT(length > 0);
-        SkAutoTMalloc<uint8_t> buffer(length);
-
-        memcpy(buffer.get(), src, *headerLen);
-        uint8_t* const resultData = &(buffer[*headerLen]);
+        SkMemoryStream* result =
+            new SkMemoryStream(*headerLen + *dataLen + *trailerLen);
+        memcpy((char*)result->getAtPos(), src, *headerLen);
+        result->seek(*headerLen);
 
         const uint8_t* hexData = src + *headerLen;
         const uint8_t* trailer = hexData + hexDataLen;
@@ -253,19 +236,21 @@ static SkData* handle_type1_stream(SkStream* srcStream, size_t* headerLen,
             } else {
                 dataByte |= curNibble;
                 highNibble = true;
-                resultData[outputOffset++] = dataByte;
+                ((char *)result->getAtPos())[outputOffset++] = dataByte;
             }
         }
         if (!highNibble) {
-            resultData[outputOffset++] = dataByte;
+            ((char *)result->getAtPos())[outputOffset++] = dataByte;
         }
         SkASSERT(outputOffset == *dataLen);
+        result->seek(*headerLen + outputOffset);
 
-        uint8_t* const resultTrailer = &(buffer[*headerLen + outputOffset]);
-        memcpy(resultTrailer, src + *headerLen + hexDataLen, *trailerLen);
-
-        return SkData::NewFromMalloc(buffer.detach(), length);
+        memcpy((char *)result->getAtPos(), src + *headerLen + hexDataLen,
+               *trailerLen);
+        result->rewind();
+        return result;
     }
+
     return NULL;
 }
 
@@ -571,8 +556,9 @@ static SkPDFStream* generate_tounicode_cmap(
     append_cmap_sections(glyphToUnicode, subset, &cmap, multiByteGlyphs,
                          firstGlyphID, lastGlyphID);
     append_cmap_footer(&cmap);
-    SkAutoTUnref<SkData> cmapData(cmap.copyToData());
-    return new SkPDFStream(cmapData.get());
+    SkAutoTUnref<SkMemoryStream> cmapStream(new SkMemoryStream());
+    cmapStream->setData(cmap.copyToData())->unref();
+    return new SkPDFStream(cmapStream.get());
 }
 
 #if defined (SK_SFNTLY_SUBSETTER)
@@ -588,7 +574,6 @@ static size_t get_subset_font_stream(const char* fontName,
                                      SkPDFStream** fontStream) {
     int ttcIndex;
     SkAutoTUnref<SkStream> fontData(typeface->openStream(&ttcIndex));
-    SkASSERT(fontData.get());
 
     size_t fontSize = fontData->getLength();
 
@@ -1310,7 +1295,7 @@ bool SkPDFType1Font::addFontDescriptor(int16_t defaultWidth) {
     size_t data SK_INIT_TO_AVOID_WARNING;
     size_t trailer SK_INIT_TO_AVOID_WARNING;
     SkAutoTUnref<SkStream> rawFontData(typeface()->openStream(&ttcIndex));
-    SkData* fontData = handle_type1_stream(rawFontData.get(), &header, &data,
+    SkStream* fontData = handleType1Stream(rawFontData.get(), &header, &data,
                                            &trailer);
     if (fontData == NULL) {
         return false;