SkPDF: SkPDFStream takes only SkStreamAsset

src/pdf/SkPDFStream.cpp

 /*
  * Copyright 2010 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #include "SkData.h"
 #include "SkDeflate.h"
 #include "SkPDFStream.h"
 #include "SkStream.h"
 #include "SkStreamPriv.h"
 
 SkPDFStream::~SkPDFStream() {}
 
 void SkPDFStream::drop() {
     fCompressedData.reset(nullptr);
     this->SkPDFDict::drop();
 }
 
 void SkPDFStream::emitObject(SkWStream* stream,
                              const SkPDFObjNumMap& objNumMap,
                              const SkPDFSubstituteMap& substitutes) const {
     SkASSERT(fCompressedData);
     this->INHERITED::emitObject(stream, objNumMap, substitutes);
     // duplicate (a cheap operation) preserves const on fCompressedData.
-    std::unique_ptr<SkStreamRewindable> dup(fCompressedData->duplicate());
+    std::unique_ptr<SkStreamAsset> dup(fCompressedData->duplicate());
     SkASSERT(dup);
     SkASSERT(dup->hasLength());
     stream->writeText(" stream\n");
     stream->writeStream(dup.get(), dup->getLength());
     stream->writeText("\nendstream");
 }
 
 
-void SkPDFStream::setData(SkStream* stream) {
+void SkPDFStream::setData(SkStreamAsset* stream) {
     SkASSERT(!fCompressedData);  // Only call this function once.
     SkASSERT(stream);
     // Code assumes that the stream starts at the beginning.
 
     #ifdef SK_PDF_LESS_COMPRESSION
-    std::unique_ptr<SkStreamRewindable> duplicate(stream->duplicate());
+    std::unique_ptr<SkStreamAsset> duplicate(stream->duplicate());
+    SkASSERT(duplicate && duplicate->hasLength());
     if (duplicate && duplicate->hasLength()) {
         this->insertInt("Length", duplicate->getLength());
         fCompressedData.reset(duplicate.release());
         return;
     }
     #endif
 
     SkDynamicMemoryWStream compressedData;
     SkDeflateWStream deflateWStream(&compressedData);
     SkStreamCopy(&deflateWStream, stream);
     deflateWStream.finalize();
     size_t length = compressedData.bytesWritten();
 
+    SkASSERT(stream->hasLength());
     if (stream->hasLength()) {
-        std::unique_ptr<SkStreamRewindable> dup(stream->duplicate());
+        std::unique_ptr<SkStreamAsset> dup(stream->duplicate());
+        SkASSERT(stream->hasLength());
+        SkASSERT(stream->getLength() == dup->getLength());
+        SkASSERT(dup && dup->hasLength());
         if (dup && dup->hasLength() &&
             dup->getLength() <= length + strlen("/Filter_/FlateDecode_")) {
             this->insertInt("Length", dup->getLength());
             fCompressedData.reset(dup.release());
             return;
         }
     }
     fCompressedData.reset(compressedData.detachAsStream());
     this->insertName("Filter", "FlateDecode");
     this->insertInt("Length", length);
 }