debugFindConstructingStackFrame static method

@visibleForTesting String? debugFindConstructingStackFrame([ StackTrace? stackTrace ])

Finds the first non-constructor frame in the stack trace.

stackTrace defaults to StackTrace.current.

Implementation

@visibleForTesting
static String? debugFindConstructingStackFrame([StackTrace? stackTrace]) {
  String? stackFrame;

  assert(() {
    if (debugAddStackTraceInObserverName) {
      final stackTraceString = (stackTrace ?? StackTrace.current).toString();
      final frames = LineSplitter.split(stackTraceString).toList();
      final rawStackFrame = frames
          .asMap()
          .entries
          // We are skipping frames representing:
          // 1. The anonymous function in the assert
          // 2. The debugFindConstructingStackFrame method
          // 3. The constructor invoking debugFindConstructingStackFrame
          //
          // The 4th frame is either user source (which is what we want), or
          // an Observer subclass' constructor (which we skip past with the
          // regex)
          .skip(3)
          // Search for the first non-constructor frame
          .where((entry) {
            if (_constructorStackFramePattern.hasMatch(entry.value)) {
              return false;
            }
            // Wasm emits a constructor entry immediately after its
            // initializer frame. Both belong to construction, not the caller.
            return !(entry.value.contains(':wasm-function[') &&
                frames[entry.key - 1].contains('(initializer)'));
          })
          .map((entry) => entry.value)
          .firstWhere((_) => true, orElse: () => '');

      final stackFrameCore =
          _stackFrameCleanUpPattern.firstMatch(rawStackFrame)?.group(1);
      final cleanedStackFrame = stackFrameCore == null
          ? null
          : 'Observer constructed from: $stackFrameCore';

      stackFrame = cleanedStackFrame;
    }

    return true;
  }());

  return stackFrame;
}