DevTools: Support asynchronous call stacks on backend.

Source/core/inspector/AsyncCallStackTracker.cpp

+/*
+ * Copyright (C) 2013 Google Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * 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.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 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 THE COPYRIGHT
+ * OWNER OR 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.
+ */
+
+#include "config.h"
+#include "core/inspector/AsyncCallStackTracker.h"
+
+#define DUMP_ASYNC_CALLS_TRACKER_STATS 0
+#if DUMP_ASYNC_CALLS_TRACKER_STATS
+#include "wtf/DataLog.h"
+#endif
+
+namespace WebCore {
+
+#if DUMP_ASYNC_CALLS_TRACKER_STATS
+namespace {
+unsigned totalAsyncCallStacks = 0;
+}
+#endif
+
+AsyncCallStackTracker::AsyncCallStack::AsyncCallStack(const ScriptValue& callFrames)
+    : m_callFrames(callFrames)
+{
+#if DUMP_ASYNC_CALLS_TRACKER_STATS
+    dataLogF("AsyncCallStack::AsyncCallStack() %u\n", ++totalAsyncCallStacks);

[yurys, 2013/12/04 15:25:52]

What's the point in this dataLogF, why not printf?

[aandrey, 2013/12/04 15:57:26]

it's the same essentially. plus there is a way to change stdout/stderr to a file

[yurys, 2013/12/05 11:37:48]

Then printf should be preferred, I don't see dataLogF to be used outside of some
basic classes in WTF.

[aandrey, 2013/12/05 13:03:40]

Done.

+#endif
+}
+
+AsyncCallStackTracker::AsyncCallStack::~AsyncCallStack()
+{
+#if DUMP_ASYNC_CALLS_TRACKER_STATS
+    dataLogF("AsyncCallStack::~AsyncCallStack() %u\n", --totalAsyncCallStacks);
+#endif
+}
+
+AsyncCallStackTracker::AsyncCallStackTracker()
+    : m_maxAsyncCallStackDepth(DUMP_ASYNC_CALLS_TRACKER_STATS ? 4 : 0)
+{
+}
+
+void AsyncCallStackTracker::setAsyncCallStackDepth(int depth)
+{
+    if (depth <= 0) {
+        m_maxAsyncCallStackDepth = 0;
+        clear();
+    } else {
+        m_maxAsyncCallStackDepth = depth;
+    }
+}
+
+const AsyncCallStackTracker::AsyncCallChain* AsyncCallStackTracker::currentAsyncCallChain() const
+{
+    if (m_currentAsyncCallChain)
+        ensureMaxAsyncCallChainDepth(m_currentAsyncCallChain.get(), m_maxAsyncCallStackDepth);
+    return m_currentAsyncCallChain.get();
+}
+
+void AsyncCallStackTracker::didInstallTimer(int timerId, bool singleShot, ScriptValue callFrames)
+{
+    if (!isEnabled() || !validateCallFrames(callFrames))

[yurys, 2013/12/04 15:25:52]

ASSERT(isEnabled()) as you already check it on the caller's side.

[aandrey, 2013/12/04 15:57:26]

Done.

+        return;
+    ASSERT(timerId > 0);
+    m_timerCallChains.set(timerId, createAsyncCallChain(callFrames));
+    if (!singleShot)
+        m_intervalTimerIds.add(timerId);
+}
+
+void AsyncCallStackTracker::didRemoveTimer(int timerId)
+{
+    if (!isEnabled() || timerId <= 0)

[yurys, 2013/12/04 15:25:52]

How can timerId be <= 0 ? Maybe ASSERT as in didInstallTimer?

[aandrey, 2013/12/04 15:57:26]

Easy:
  window.clearTimeout(-5);

But we do want to pass the invalid ids to agents, for example to
DOMDebuggerAgent, to stop on clearTimeout, thus we can't filter this out in
DOMTimer.cpp

Timer ID in didInstallTimer comes from DOMTimer.cpp, thus should always be
valid.

[yurys, 2013/12/05 11:37:48]

Got it, thanks for explaining.

+        return;
+    m_intervalTimerIds.remove(timerId);
+    m_timerCallChains.remove(timerId);
+}
+
+void AsyncCallStackTracker::willFireTimer(int timerId)
+{
+    if (!isEnabled())
+        return;
+    ASSERT(timerId > 0);
+    ASSERT(!m_currentAsyncCallChain);
+    if (m_intervalTimerIds.contains(timerId))
+        m_currentAsyncCallChain = m_timerCallChains.get(timerId);
+    else
+        m_currentAsyncCallChain = m_timerCallChains.take(timerId);
+}
+
+void AsyncCallStackTracker::didRequestAnimationFrame(int callbackId, ScriptValue callFrames)
+{
+    if (!isEnabled() || !validateCallFrames(callFrames))
+        return;
+    ASSERT(callbackId > 0);
+    m_animationFrameCallChains.set(callbackId, createAsyncCallChain(callFrames));
+}
+
+void AsyncCallStackTracker::didCancelAnimationFrame(int callbackId)
+{
+    if (!isEnabled() || callbackId <= 0)
+        return;
+    m_animationFrameCallChains.remove(callbackId);
+}
+
+void AsyncCallStackTracker::willFireAnimationFrame(int callbackId)
+{
+    if (!isEnabled())
+        return;
+    ASSERT(callbackId > 0);
+    ASSERT(!m_currentAsyncCallChain);
+    m_currentAsyncCallChain = m_animationFrameCallChains.take(callbackId);
+}
+
+void AsyncCallStackTracker::didFireAsyncCall()
+{
+    m_currentAsyncCallChain = 0;
+}
+
+PassRefPtr<AsyncCallStackTracker::AsyncCallChain> AsyncCallStackTracker::createAsyncCallChain(ScriptValue& callFrames)
+{
+    ASSERT(isEnabled());
+    RefPtr<AsyncCallChain> chain = adoptRef(m_currentAsyncCallChain ? new AsyncCallStackTracker::AsyncCallChain(*m_currentAsyncCallChain) : new AsyncCallStackTracker::AsyncCallChain());
+    ensureMaxAsyncCallChainDepth(chain.get(), m_maxAsyncCallStackDepth - 1);
+    chain->m_callStacks.prepend(adoptRef(new AsyncCallStackTracker::AsyncCallStack(callFrames)));
+    return chain.release();
+}
+
+void AsyncCallStackTracker::ensureMaxAsyncCallChainDepth(AsyncCallChain* chain, unsigned maxDepth)
+{
+    while (chain->m_callStacks.size() > maxDepth)
+        chain->m_callStacks.removeLast();
+}
+
+bool AsyncCallStackTracker::validateCallFrames(ScriptValue& callFrames)
+{
+    return !callFrames.hasNoValue() && callFrames.isObject();
+}
+
+void AsyncCallStackTracker::clear()
+{
+    m_currentAsyncCallChain = 0;
+    m_intervalTimerIds.clear();
+    m_timerCallChains.clear();
+    m_animationFrameCallChains.clear();
+}
+
+} // namespace WebCore