Move SkPDFStream back to SkStream to save memory.

src/core/SkStream.cpp

Index: src/core/SkStream.cpp
diff --git a/src/core/SkStream.cpp b/src/core/SkStream.cpp
index 1022d183d93cc4bb36526f437c04f89f520ff856..2c27c5b1da72a3d44129d1ba9b0d8b59fa43cc54 100644
--- a/src/core/SkStream.cpp
+++ b/src/core/SkStream.cpp
@@ -907,3 +907,34 @@ SkData* SkCopyStreamToData(SkStream* stream) {
     } while (!stream->isAtEnd());
     return tempStream.copyToData();
 }
+
+SkStreamRewindable* SkStreamToStreamRewindable(SkStream* stream) {

[bungeman-skia, 2014/07/11 21:43:38]

I would prefer this to be SkStreamRewindableFromSkStream so that 1) it looks
more like a constructor call and 2) the parts of the name are closer to the
values they refer to. On the other hand, the other functions here use the
backward 'To' form, so I can't be too ornery.

[hal.canary, 2014/07/12 00:58:49]

Done.

+    if (!stream) {
+        return NULL;
+    }
+    SkAutoTUnref<SkStreamRewindable> dupStream(stream->duplicate());
+    if (dupStream) {
+        return dupStream.detach();
+    }
+    if (stream->hasLength()) {
+        size_t length = stream->getLength();
+        SkAutoMalloc allocMemory(length);
+        SkAssertResult(stream->rewind());

[bungeman-skia, 2014/07/11 21:43:38]

I wouldn't assert this, just because a stream has a length doesn't imply that
it's rewindable (though I must admit that it seems unlikely). I think I would
just 'stream->rewind()' before this 'if' block and remove the
'SkAssertResult(stream->rewind());' below (line 929).

Then, if 'hasPosition' you can subtract that from the length.

[hal.canary, 2014/07/12 00:58:49]

Done.

+        SkAssertResult(length == stream->read(allocMemory.get(), length));
+        SkAssertResult(stream->rewind());

[bungeman-skia, 2014/07/11 21:43:38]

I see no reason to try to leave this in a known state, since other paths do not.
I wouldn't bother with this and just comment that the passed stream is left at
an unknown position.

[hal.canary, 2014/07/12 00:58:49]

Done.

+        SkAutoTUnref<SkData> data(
+                SkData::NewFromMalloc(allocMemory.get(), length));
+        return SkNEW_ARGS(SkMemoryStream, (data.get()));
+    }
+    SkAssertResult(stream->rewind());
+    SkDynamicMemoryWStream tempStream;
+    const size_t bufferSize = 4096;
+    char buffer[bufferSize];
+    do {
+        size_t bytesRead = stream->read(buffer, bufferSize);
+        tempStream.write(buffer, bytesRead);
+    } while (!stream->isAtEnd());
+    SkAssertResult(stream->rewind());

[bungeman-skia, 2014/07/11 21:43:38]

Same as above (line 924), I see no reason to try to rewind anything just to
leave the stream in a known state.

[hal.canary, 2014/07/12 00:58:49]

Done.

+    return tempStream.detachAsStream();  // returns a SkBlockMemoryStream,
+                                         // cheaper than copying to SkData
+}