Stream scripts to V8 as they load - Blink side.

Source/bindings/core/v8/V8ScriptStreamer.h

+/*
+ * Copyright (C) 2014 Google Inc. All rights reserved.

[haraken, 2014/08/17 16:05:27]

Nit: Use the 3-line copyright.

// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

[marja, 2014/08/20 11:45:55]

Done.

+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
+ * THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef V8ScriptStreamer_h
+#define V8ScriptStreamer_h
+
+#include "wtf/RefCounted.h"
+
+#include <v8.h>
+
+namespace blink {
+
+class HTMLScriptRunner;
+class PendingScript;
+class ScriptResource;
+class SourceStream;
+
+// V8ScriptStreamer streams incomplete script data to V8 so that it can be
+// parsed while it's loaded. PendingScript holds a reference to
+// V8ScriptStreamer. At the moment, V8ScriptStreamer is only used for parser
+// blocking scripts; this means that the Document stays stable and no other
+// scripts are executing while we're streaming. It is possible, though, that
+// Document and the PendingScript are destroyed while the streaming is in
+// progress, and V8ScriptStreamer handles it gracefully.
+class V8ScriptStreamer : public RefCounted<V8ScriptStreamer> {

[haraken, 2014/08/17 16:05:27]

(We might want to move V8ScriptStreamer to oilpan's heap, but it's OK for now to
use a RefPtr. As far as I see, it looks like that there are a couple of
non-trivial issues in moving V8ScriptStreamer to oilpan's heap.)

[haraken, 2014/08/17 16:05:27]

V8ScriptStreamer => ScriptStreamer

We're planning to drop a "V8" prefix from V8-binding classes, so let's not add
the prefix to newly introduced classes.

[marja, 2014/08/20 11:45:55]

Acknowledged.

[marja, 2014/08/20 11:45:56]

Done.

+public:
+    static bool startStreaming(PendingScript*, HTMLScriptRunner*);

[haraken, 2014/08/17 16:05:27]

Add a comment about what startStreaming() does.

[marja, 2014/08/20 11:45:55]

Done.

+
+    bool streamingInProgress() const { return !m_loadingDone || !m_v8Done; }
+
+    v8::ScriptCompiler::StreamedSource* source() { return &m_source; }
+
+    // Called when data arrives from the network.
+    void notifyAppendData();
+    void notifyFinished();
+
+    // Called when we have streamed all data to V8 and it has processed it.
+    void streamingComplete();
+
+    // Cancel is called if the PendingScript is deleted and we don't need to
+    // stream the script any more. After calling cancel, PendingScript will drop
+    // its reference, and V8ScriptStreamer takes care of deleting itself.
+    void cancel();
+
+    unsigned cachedDataDataType() const { return m_cachedDataDataType; }
+
+private:
+    V8ScriptStreamer(PendingScript*, HTMLScriptRunner*);

[haraken, 2014/08/17 16:05:27]

Why do both V8ScriptStreamer's constructor and startStreaming() need to take the
same parameters? Can't the startStreaming() use the PendingScript and
HTMLScriptRunner that are passed to V8ScriptStreamer's constructor?

[marja, 2014/08/20 11:45:55]

startStreaming is a static function which constructs a V8ScriptStreamer
internally and attaches it to the PendingScript. So it's not supposed to be used
like "first create a V8ScriptStreamer and then call start on it".

+
+    // This pointer is weak, and the PendingScript can be deleted before
+    // V8ScriptStreamer. However, it'll notify V8ScriptStreamer of its deletion
+    // by calling cancel().
+    PendingScript* m_script;
+    HTMLScriptRunner* m_runner;
+    SourceStream* m_stream;
+    v8::ScriptCompiler::StreamedSource m_source;
+    bool m_loadingDone; // Whether loading from the network is done.
+    bool m_v8Done; // Whether the V8 side processing is done.
+    unsigned m_cachedDataDataType;
+};
+
+} // namespace blink
+
+#endif // V8ScriptStreamer_h