Stream scripts to V8 as they load - Blink side.

Source/bindings/core/v8/ScriptStreamerThread.cpp

+// 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.
+
+#include "config.h"
+#include "bindings/core/v8/ScriptStreamerThread.h"
+
+#include "bindings/core/v8/ScriptStreamer.h"
+#include "platform/Task.h"
+#include "public/platform/Platform.h"
+#include "wtf/MainThread.h"
+#include "wtf/PassOwnPtr.h"
+
+namespace blink {
+
+static ScriptStreamerThread* s_sharedThread = 0;
+
+void ScriptStreamerThread::init()
+{
+    ASSERT(!s_sharedThread);
+    ASSERT(isMainThread());
+    s_sharedThread = new ScriptStreamerThread();
+}
+
+void ScriptStreamerThread::shutdown()
+{
+    ASSERT(s_sharedThread);
+    // currentThread will always be non-null in production, but can be null in
+    // Chromium unit tests.
+    if (blink::Platform::current()->currentThread() && s_sharedThread->isRunning()) {
+        // The streaming task should exit soon, because the corresponding
+        // PendingScript should already be destroyed, and it has cancelled the
+        // streaming. However, the V8 side operations might still be ongoing.
+        // When V8 asks for more data the next time, the cancelling will take
+        // effect.
+        TaskSynchronizer taskSynchronizer;
+        s_sharedThread->postTask(new Task(WTF::bind(&ScriptStreamerThread::markAsCompleted, s_sharedThread, &taskSynchronizer)));

[haraken, 2014/09/10 05:57:51]

It's not nice to block the shutdown sequence by waiting for V8 to complete the
remaining parsing task, but I'm OK with this because the situation will rarely
happen.

[marja, 2014/09/11 09:15:37]

It doesn't make the situation worse than now: previously the main thread used to
call Parse and while that is happening, nothing else is.

+        taskSynchronizer.waitForTaskCompletion();
+    }
+    delete s_sharedThread;
+    s_sharedThread = 0;
+}
+
+ScriptStreamerThread* ScriptStreamerThread::shared()
+{
+    return s_sharedThread;
+}
+
+void ScriptStreamerThread::postTask(WebThread::Task* task)
+{
+    ASSERT(isMainThread());
+    m_runningTask = true;

[haraken, 2014/09/10 05:57:51]

Shall we add ASSERT(!m_runningTask) before this line?

[marja, 2014/09/11 09:15:37]

Done.

+    platformThread().postTask(task);
+}
+
+blink::WebThread& ScriptStreamerThread::platformThread()
+{
+    if (!isRunning()) {
+        m_thread = adoptPtr(blink::Platform::current()->createThread("ScriptStreamerThread"));
+    }
+    return *m_thread;
+}
+
+ScriptStreamingTask::ScriptStreamingTask(v8::ScriptCompiler::ScriptStreamingTask* task, ScriptStreamer* streamer)
+    : m_v8Task(adoptPtr(task)), m_streamer(streamer) { }
+
+void ScriptStreamingTask::run()
+{
+    // Running the task can and will block: SourceStream::GetSomeData will get
+    // called and it will block and wait for data from the network.
+    m_v8Task->Run();
+    // Post a task to the main thread to signal that V8 has completed the
+    // streaming.
+    callOnMainThread(&ScriptStreamerThread::taskDone, 0);
+    callOnMainThread(WTF::bind(&ScriptStreamer::streamingComplete, m_streamer));
+}
+
+} // namespace blink