Dartium: do not call back into Dart code to parse or generate a stack trace.

Source/bindings/dart/DartUtilities.cpp

Index: Source/bindings/dart/DartUtilities.cpp
diff --git a/Source/bindings/dart/DartUtilities.cpp b/Source/bindings/dart/DartUtilities.cpp
index 49f7d85db026762588af6b95cd6523d86c252c63..e8498c2294b295a1a94fea5416629efa468ae259 100644
--- a/Source/bindings/dart/DartUtilities.cpp
+++ b/Source/bindings/dart/DartUtilities.cpp
@@ -953,65 +953,56 @@ PassRefPtr<ScriptArguments> DartUtilities::createScriptArguments(Dart_Handle arg
     return ScriptArguments::create(DartUtilities::currentScriptState(), arguments);
 }
 
-static PassRefPtr<ScriptCallStack> createScriptCallStackFromParsedStackTrace(Dart_Handle parsedStackTrace, Dart_Handle exception)
+static PassRefPtr<ScriptCallStack> createScriptCallStackFromStackTrace(Dart_ExceptionStackTrace stackTrace)
 {
-    Vector<Dart_Handle> callFrames;
-    DartUtilities::extractListElements(parsedStackTrace, exception, callFrames);
-    if (exception)
+    intptr_t frameCount = 0;
+    Dart_Handle result = Dart_StacktraceLength(stackTrace, &frameCount);
+    if (Dart_IsError(result))
         return 0;

[siva, 2013/11/08 18:17:17]

Why do we need this API function at all why not just go with
DartStacktraceFrameInfo(....) returning an error when frameIndex has reached the
end of the stacktrace.

The loop at the bottom can converted into a
do {
  ...
} while(!error && frameIndex < ScriptCallStack::maxCallStackSizeToCapture);

[rmacnak, 2013/11/12 00:05:43]

As discussed, now sharing with the debugging API's Dart_StackTraceLength.

 
-    size_t frameCount = callFrames.size();
     if (frameCount > ScriptCallStack::maxCallStackSizeToCapture)
         frameCount = ScriptCallStack::maxCallStackSizeToCapture;
 
     Vector<ScriptCallFrame> scriptCallStackFrames;
-    for (size_t i = 0; i < frameCount; i++) {
-        Dart_Handle callFrame = callFrames[i];
-        Vector<Dart_Handle> fields;
-        DartUtilities::extractListElements(callFrame, exception, fields);
-        if (exception)
+    for (intptr_t frameIndex = 0; frameIndex < frameCount; frameIndex++) {
+        Dart_Handle dartFunctionName;
+        Dart_Handle dartScriptUrl;
+        intptr_t lineNumber = 0;
+        intptr_t columnNumber = 0;
+        result = Dart_StacktraceFrameInfo(stackTrace, frameIndex, &dartFunctionName, &dartScriptUrl, &lineNumber, &columnNumber);
+        if (Dart_IsError(result))
             return 0;
-        ASSERT(fields.size() == 4);
-        String functionName = DartUtilities::toString(fields[0]);
-        String sourceName = DartUtilities::toString(fields[1]);
-        int lineNumber = DartUtilities::toInteger(fields[2], exception);
-        if (exception)
+
+        const char* cstr = 0;
+        result = Dart_StringToCString(dartFunctionName, &cstr);
+        if (Dart_IsError(result))
             return 0;
-        int columnNumber = DartUtilities::toInteger(fields[3], exception);
-        if (exception)
+        String functionName(cstr);

[vsm, 2013/11/07 22:51:50]

There's a DartUtilities method to go from Dart_Handle to String.

[rmacnak, 2013/11/12 00:05:43]

D'oh!

+        result = Dart_StringToCString(dartScriptUrl, &cstr);
+        if (Dart_IsError(result))
             return 0;
-        scriptCallStackFrames.append(ScriptCallFrame(functionName, "undefined", sourceName, lineNumber, columnNumber));
+        String scriptUrl(cstr);
+
+        // FIXME
+        const char* scriptName = "undefined";
+        // FIXME

[vsm, 2013/11/07 22:51:50]

Can you add some text to these fixmes?  Not clear what you intend to fix in the
latter case?

[rmacnak, 2013/11/12 00:05:43]

See the comments in earlier patch sets. Also added some discussion to the code.

+        if (columnNumber != -1)

[vsm, 2013/11/07 22:51:50]

Under what circumstance is this true?

If this check is needed, it should be earlier - no need to do all the string
conversion above to throw away the results.

+            scriptCallStackFrames.append(ScriptCallFrame(functionName, scriptName, scriptUrl, lineNumber, columnNumber));
     }
-    if (!frameCount)
+    if (scriptCallStackFrames.isEmpty())
         scriptCallStackFrames.append(ScriptCallFrame("undefined", "undefined", "undefined", 0, 0));
 
     return ScriptCallStack::create(scriptCallStackFrames);
 }
 
-static PassRefPtr<ScriptCallStack> createScriptCallStackFromStackTrace(Dart_Handle stackTrace, Dart_Handle& exception)
-{
-    Dart_Handle parsedStackTrace = DartUtilities::invokeUtilsMethod("parseStackTrace", 1, &stackTrace);
-    if (!DartUtilities::checkResult(parsedStackTrace, exception))
-        return 0;
-
-    return createScriptCallStackFromParsedStackTrace(parsedStackTrace, exception);
-}
-
 PassRefPtr<ScriptCallStack> DartUtilities::createScriptCallStack()
 {
-    Dart_ExceptionPauseInfo previousPauseInfo = Dart_GetExceptionPauseInfo();
-    if (previousPauseInfo != kNoPauseOnExceptions)
-        Dart_SetExceptionPauseInfo(kNoPauseOnExceptions);
-    Dart_Handle exception = 0;
-    Dart_Handle parsedStackTrace = DartUtilities::invokeUtilsMethod("captureParsedStackTrace", 0, 0);
-
-    if (previousPauseInfo != kNoPauseOnExceptions)
-        Dart_SetExceptionPauseInfo(previousPauseInfo);
-
-    if (!DartUtilities::checkResult(parsedStackTrace, exception))
-        return 0;
-
-    return createScriptCallStackFromParsedStackTrace(parsedStackTrace, exception);
+    Dart_ExceptionStackTrace trace = 0;
+    Dart_Handle result = Dart_CurrentStacktrace(&trace);
+    ASSERT(!Dart_IsError(result));
+    ASSERT(!Dart_IsNull(result));
+    ASSERT(trace);
+    return createScriptCallStackFromStackTrace(trace);
 }
 
 Dart_WeakPersistentHandle DartUtilities::createPrologueWeakPersistentHandle(Dart_Handle object, void* peer, Dart_WeakPersistentHandleFinalizer weakCallback)
@@ -1136,12 +1127,10 @@ void DartUtilities::reportProblem(ScriptExecutionContext* context, Dart_Handle r
             errorMessage = String("Exception: ") + DartUtilities::toString(exception);
 
         // Print the stack trace.
-        Dart_Handle stacktrace = Dart_ErrorGetStacktrace(result);
-        ASSERT(!Dart_IsError(stacktrace));
-        Dart_Handle stackTraceConversionException = 0;
-        callStack = createScriptCallStackFromStackTrace(stacktrace, stackTraceConversionException);
-        if (stackTraceConversionException)
-            errorMessage.append(String("\nError converting stack trace to a string: ") + DartUtilities::toString(stackTraceConversionException));
+        Dart_ExceptionStackTrace stacktrace;
+        Dart_Handle traceResult = Dart_ErrorGetStacktrace(result, &stacktrace);
+        ASSERT(!Dart_IsError(traceResult));
+        callStack = createScriptCallStackFromStackTrace(stacktrace);
     }
 
     if (context && context->isDocument()) {