SkPDF: Memory improvements for PDF Streams

src/pdf/SkPDFTypes.cpp

Index: src/pdf/SkPDFTypes.cpp
diff --git a/src/pdf/SkPDFTypes.cpp b/src/pdf/SkPDFTypes.cpp
index 2fe408b1cc879abd910aba5af4e56355a3acb70e..9bb9dee49760840924cee3b022ee90db5d7dcf73 100644
--- a/src/pdf/SkPDFTypes.cpp
+++ b/src/pdf/SkPDFTypes.cpp
@@ -6,15 +6,10 @@
  * found in the LICENSE file.
  */
 
+#include "SkDeflate.h"
 #include "SkPDFTypes.h"
 #include "SkPDFUtils.h"
-#include "SkStream.h"
-
-#ifdef SK_BUILD_FOR_WIN
-    #define SNPRINTF    _snprintf
-#else
-    #define SNPRINTF    snprintf
-#endif
+#include "SkStreamPriv.h"
 
 ////////////////////////////////////////////////////////////////////////////////
 
@@ -355,6 +350,13 @@ void SkPDFDict::emitObject(SkWStream* stream,
                            const SkPDFObjNumMap& objNumMap,
                            const SkPDFSubstituteMap& substitutes) const {
     stream->writeText("<<");
+    this->emitAll(stream, objNumMap, substitutes);
+    stream->writeText(">>");
+}
+
+void SkPDFDict::emitAll(SkWStream* stream,
+                        const SkPDFObjNumMap& objNumMap,
+                        const SkPDFSubstituteMap& substitutes) const {
     for (int i = 0; i < fRecords.count(); i++) {
         fRecords[i].fKey.emitObject(stream, objNumMap, substitutes);
         stream->writeText(" ");
@@ -363,7 +365,6 @@ void SkPDFDict::emitObject(SkWStream* stream,
             stream->writeText("\n");
         }
     }
-    stream->writeText(">>");
 }
 
 void SkPDFDict::addResources(SkPDFObjNumMap* catalog,
@@ -439,6 +440,41 @@ void SkPDFDict::clear() {
 
 ////////////////////////////////////////////////////////////////////////////////
 
+void SkPDFSharedStream::emitObject(
+        SkWStream* stream,
+        const SkPDFObjNumMap& objNumMap,
+        const SkPDFSubstituteMap& substitutes) const {
+    SkDynamicMemoryWStream buffer;
+    SkDeflateWStream deflateWStream(&buffer);
+    // Since emitObject is const, this function doesn't change the dictionary.
+    SkAutoTDelete<SkStreamAsset> dup(fAsset->duplicate());  // Cheap copy
+    SkASSERT(dup);
+    SkStreamCopy(&deflateWStream, dup.get());
+    deflateWStream.finalize();
+    size_t length = buffer.bytesWritten();
+    stream->writeText("<<");
+    fDict->emitAll(stream, objNumMap, substitutes);
+    stream->writeText("\n");
+    SkPDFUnion::Name("Length").emitObject(stream, objNumMap, substitutes);
+    stream->writeText(" ");
+    SkPDFUnion::Int(length).emitObject(stream, objNumMap, substitutes);
+    stream->writeText("\n");
+    SkPDFUnion::Name("Filter").emitObject(stream, objNumMap, substitutes);
+    stream->writeText(" ");
+    SkPDFUnion::Name("FlateDecode").emitObject(stream, objNumMap, substitutes);
+    stream->writeText(">>");
+    stream->writeText(" stream\n");
+    buffer.writeToStream(stream);
+    stream->writeText("\nendstream");
+}
+
+void SkPDFSharedStream::addResources(
+        SkPDFObjNumMap* catalog, const SkPDFSubstituteMap& substitutes) const {
+    fDict->addResources(catalog, substitutes);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
 SkPDFSubstituteMap::~SkPDFSubstituteMap() {
     fSubstituteMap.foreach(
             [](SkPDFObject*, SkPDFObject** v) { (*v)->unref(); });