Support merged Dart-JS callstacks

Source/bindings/common/StackTrace.cpp

Index: Source/bindings/common/StackTrace.cpp
diff --git a/Source/bindings/common/StackTrace.cpp b/Source/bindings/common/StackTrace.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..949e7327e9075e888afd5b9678310a329b4764e9
--- /dev/null
+++ b/Source/bindings/common/StackTrace.cpp
@@ -0,0 +1,125 @@
+/*
+ * Copyright (C) 2014 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 "bindings/common/StackTrace.h"
+
+namespace WebCore {
+
+StackTrace::StackTrace() :
+    m_hasJavaScript(false),
+    m_hasDart(false),
+    m_dartStackTrace(0),
+    m_v8ScriptState(0),
+    m_dartScriptState(0)
+{
+}
+
+StackTrace::StackTrace(const StackTrace& javaScriptStackTrace, const StackTrace& dartStackTrace)
+{
+    ASSERT(!javaScriptStackTrace.hasDart() && !dartStackTrace.hasJavaScript());
+
+    if (javaScriptStackTrace.hasJavaScript()) {
+        m_hasJavaScript = true;
+        m_scriptValue = javaScriptStackTrace.asJavaScript();
+        m_v8ScriptState = javaScriptStackTrace.v8ScriptState();
+    } else {
+        m_hasJavaScript = false;
+        m_v8ScriptState = 0;
+    }
+
+    if (dartStackTrace.hasDart()) {
+        m_hasDart = true;
+        m_dartStackTrace = dartStackTrace.asDart();
+        m_dartScriptState = dartStackTrace.dartScriptState();
+    } else {
+        m_hasDart = false;
+        m_dartStackTrace = 0;
+        m_dartScriptState = 0;
+    }
+}
+
+StackTrace::StackTrace(const ScriptValue& stackTrace, V8ScriptState* v8ScriptState) :
+    m_hasJavaScript(!stackTrace.isEmpty()),
+    m_hasDart(false),
+    m_scriptValue(stackTrace),
+    m_dartStackTrace(0),
+    m_v8ScriptState(v8ScriptState),
+    m_dartScriptState(0)
+{
+}
+
+StackTrace::StackTrace(Dart_StackTrace stackTrace, DartScriptState* dartScriptState) :
+    m_hasJavaScript(false),
+    m_hasDart(!!stackTrace),
+    m_dartStackTrace(stackTrace),
+    m_v8ScriptState(0),
+    m_dartScriptState(dartScriptState)
+{
+}
+
+void StackTrace::merge(const StackTrace& other)
+{
+    if (other.hasJavaScript()) {
+        m_hasJavaScript = true;
+        m_scriptValue = other.asJavaScript();
+        m_v8ScriptState = other.v8ScriptState();

[vsm, 2014/08/29 08:42:07]

What if this StackTrace already hasJavaScript with a different m_scriptValue and
m_v8ScriptState?  Can this happen?  If so, do you really want to overwrite?

[Jacob, 2014/09/05 23:35:55]

Rolled back the changes that made StackTrace confusing and instead added a
StackTraces class
that tracks the mapping from ScriptState objects to StackTrace objects. This
could also help for the multiple DOM isolates case.

+    }
+
+    if (other.hasDart()) {
+        m_hasDart = true;
+        m_dartStackTrace = other.asDart();
+        m_dartScriptState = other.dartScriptState();

[vsm, 2014/08/29 08:42:07]

Ditto - and what happens with multiple DOM isolates?

[Jacob, 2014/09/05 23:35:55]

Fixed. See previous comment.

+    }
+}
+
+StackTraceTimestamp::StackTraceTimestamp(size_t stackDepth) : m_stackDepth(stackDepth)
+{
+    DEFINE_STATIC_LOCAL(int64_t, nextTimestamp, (0));

[vsm, 2014/08/29 08:42:08]

Maybe unsigned here?

[Jacob, 2014/09/05 23:35:55]

Removed the timestamp tracker code with the switch to tracking actual frame
pointers.

+    m_timestamp = ++nextTimestamp;

[vsm, 2014/08/29 08:42:07]

Overflow assert for good form?  Might not trigger in our lifetime. :-)

[Jacob, 2014/09/05 23:35:55]

this code was removed.

+}
+
+int64_t StackTraceTimestampTracker::getTimestamp(size_t frame)
+{
+    // The timestamp for a frame is the timestamp of the sample with the
+    // largest stack depth that does not exceed the stack depth of the frame.
+    ASSERT(!m_samples.isEmpty());
+    if (m_samples.isEmpty())
+        return 0;
+
+    // m_samples.size() will typically be less than 3 and will be at most
+    // kMaxRecursionDepth (20) so binary search isn't needed.
+    size_t i = 1;
+    while (i < m_samples.size() && m_samples[i].stackDepth() <= frame)
+        i++;
+    return m_samples[i-1].timestamp();
+}
+
+} // namespace WebCore