Stream scripts to V8 as they load - Blink side.

Source/bindings/core/v8/ScriptSourceCode.h

Index: Source/bindings/core/v8/ScriptSourceCode.h
diff --git a/Source/bindings/core/v8/ScriptSourceCode.h b/Source/bindings/core/v8/ScriptSourceCode.h
index 8cd98fb185be29c814c3ef005bdff0e81a58ad77..035fa34590d31caa4543839ffd3df29fc143f934 100644
--- a/Source/bindings/core/v8/ScriptSourceCode.h
+++ b/Source/bindings/core/v8/ScriptSourceCode.h
@@ -31,6 +31,7 @@
 #ifndef ScriptSourceCode_h
 #define ScriptSourceCode_h
 
+#include "bindings/core/v8/V8ScriptStreamer.h"
 #include "core/fetch/ResourcePtr.h"
 #include "core/fetch/ScriptResource.h"
 #include "platform/weborigin/KURL.h"
@@ -61,6 +62,14 @@ public:
     {
     }
 
+    ScriptSourceCode(PassRefPtr<V8ScriptStreamer> streamer, ScriptResource* cs)
+        : m_source(cs->script())
+        , m_resource(cs)
+        , m_streamer(streamer)
+        , m_startPosition(TextPosition::minimumPosition())
+    {
+    }
+
     bool isEmpty() const { return m_source.isEmpty(); }
 
     const String& source() const { return m_source; }
@@ -77,9 +86,12 @@ public:
     int startLine() const { return m_startPosition.m_line.oneBasedInt(); }
     const TextPosition& startPosition() const { return m_startPosition; }
 
+    V8ScriptStreamer* streamer() const { return m_streamer.get(); }
+
 private:
     String m_source;
     ResourcePtr<ScriptResource> m_resource;
+    RefPtr<V8ScriptStreamer> m_streamer;

[haraken, 2014/08/17 16:05:25]

In my understanding, V8ScriptStreamer is owned by either PendingScript (if the
script is still pending) or ScriptSourceCode (if the script is going to be
compiled). If so, can we just use an OwnPtr for V8ScriptStreamer? Do we need to
use RefPtrs?

[marja, 2014/08/20 11:45:54]

I don't think we can get away without RefPtrs; the main reason is the situation
when we're streaming.

So we have a PendingScript and then we're also streaming the script to V8.
PendingScript can go away any time, but as the V8 side is still accessing the
V8Streamer (or rather, the SourceStream it holds), it must be kept alive. So
PendingScript cannot own it. Actually, nothing on the Blink side can own it at
that point, since basically everything on the Blink side can ramp down and we
still need to give the V8 background thread some time to realize that.

Then again, when the V8 side operations have stopped, the PendingScript can own
the V8Streamer again (if the PendingScript goes away, it can be destructed).

So it's logical that at this is handled with references; both PendingScript and
the V8 side hold a reference to V8ScriptStreamer. (The V8 side reference is now
tracked with explicit ref / deref.)

However, I simplified this so that we don't have
PendingScript::releaseStreamer(), so that PendingScript will also hold a
reference until it's deleted (or set to track a different resource) - it's
simpler that way.

[haraken, 2014/08/20 15:00:18]

Makes sense, thanks for the clarification!

     mutable KURL m_url;
     TextPosition m_startPosition;
 };