public static void ShowCmd(string arguments, O2Thread.FuncVoidT1 <string> o2Callback)
{
MDbgSourcePosition pos = CommandBase.Debugger.Processes.Active.Threads.Active.CurrentSourcePosition;
if (pos == null)
{
throw new MDbgShellException("No source location");
}
string fileLoc = CommandBase.Shell.FileLocator.GetFileLocation(pos.Path);
if (fileLoc == null)
{
throw new MDbgShellException(String.Format(CultureInfo.InvariantCulture,
"Source file '{0}' not available.", pos.Path));
}
IMDbgSourceFile file = CommandBase.Shell.SourceFileMgr.GetSourceFile(fileLoc);
var ap = new ArgParser(arguments);
if (ap.Count > 1)
{
throw new MDbgShellException("Wrong # of arguments.");
}
int around;
if (ap.Exists(0))
{
around = ap.AsInt(0);
}
else
{
around = 3;
}
int lo, hi;
lo = pos.Line - around;
if (lo < 1)
{
lo = 1;
}
hi = pos.Line + around;
if (hi > file.Count)
{
hi = file.Count;
}
for (int i = lo; i < hi; i++)
{
CommandBase.WriteOutput(String.Format(CultureInfo.InvariantCulture, "{0}{1}{2}", i, i == pos.Line ? ":*" : " ",
file[i]));
}
}
public static string GetCurrentLocationInSource(MDbgEngine debugger, IShell shell)
{
if (!debugger.Processes.Active.Threads.HaveActive)
{
return(""); // we won't try to show current location
}
MDbgThread thr = debugger.Processes.Active.Threads.Active;
MDbgSourcePosition pos = thr.CurrentSourcePosition;
if (pos == null)
{
MDbgFrame f = thr.CurrentFrame;
if (f.IsManaged)
{
CorDebugMappingResult mappingResult;
uint ip;
f.CorFrame.GetIP(out ip, out mappingResult);
string s = "IP: " + ip + " @ " + f.Function.FullName + " - " + mappingResult;
return(s);
}
else
{
return("<Located in native code.>");
}
}
else
{
string fileLoc = shell.FileLocator.GetFileLocation(pos.Path);
if (fileLoc == null)
{
// Using the full path makes debugging output inconsistant during automated test runs.
// For testing purposes we'll get rid of them.
//CommandBase.WriteOutput("located at line "+pos.Line + " in "+ pos.Path);
return("located at line " + pos.Line + " in " + System.IO.Path.GetFileName(pos.Path));
}
else
{
IMDbgSourceFile file = shell.SourceFileMgr.GetSourceFile(fileLoc);
string prefixStr = pos.Line.ToString(CultureInfo.InvariantCulture) + ":";
if (pos.Line < 1 || pos.Line > file.Count)
{
shell.WriteLine("located at line " + pos.Line + " in " + pos.Path);
throw new Exception(string.Format("Could not display current location; file {0} doesn't have line {1}.",
file.Path, pos.Line));
}
Debug.Assert((pos.Line > 0) && (pos.Line <= file.Count));
return(file[pos.Line]);
}
}
}
private void loadDataFromMDbgSourcePosition(MDbgSourcePosition mDbgSourcePosition)
{
hasSourceCodeDetails = (mDbgSourcePosition != null);
if (mDbgSourcePosition != null)
{
FileName = mDbgSourcePosition.Path;
Line = mDbgSourcePosition.Line;
IsSpecial = mDbgSourcePosition.IsSpecial;
StartColumn = mDbgSourcePosition.StartColumn;
EndColumn = mDbgSourcePosition.EndColumn;
StartLine = mDbgSourcePosition.StartLine;
EndLine = mDbgSourcePosition.EndLine;
}
}
protected override void DrawGlyphWorker(PaintEventArgs e)
{
// base class does nothing.
// Draw current source-line arrows in the glyph bar.
MDbgSourcePosition pos = this.m_pos;
if (pos != null)
{
{
int iLine = pos.Line;
Bitmap bmp = this.MainForm.IsCurrentSourceActive ? m_glyphs.CurrentLineArrow : m_glyphs.NotCurrentLineArrow;
this.DrawGlyphAtLine(e, bmp, iLine);
}
}
DrawBreakpoints(e);
}
protected override void OnBreakWorker()
{
ClearHighlight();
m_pos = MainForm.CurrentSource;
if (m_pos == null)
{
return;
}
if (m_pos.Path != this.Text)
{
m_pos = null;
}
// Hilight in current source
if (m_pos != null)
{
HighlightStatementAtPos(m_pos);
}
}
public O2MDbgCurrentLocation(MDbgSourcePosition mdbgsourcePosition) : this()
{
loadDataFromMDbgSourcePosition(mdbgsourcePosition);
}
public virtual void DisplayCurrentLocation()
{
if (!Debugger.Processes.HaveActive)
{
CommandBase.WriteOutput("STOP: Process Exited");
return; // don't try to display current location
}
else
{
Debug.Assert(Debugger.Processes.HaveActive);
Object stopReason = Debugger.Processes.Active.StopReason;
Type stopReasonType = stopReason.GetType();
if (stopReasonType == typeof(StepCompleteStopReason))
{
// just ignore those
}
else if (stopReasonType == typeof(ThreadCreatedStopReason))
{
CommandBase.WriteOutput("STOP: Thread Created");
}
else if (stopReasonType == typeof(BreakpointHitStopReason))
{
MDbgBreakpoint b = (stopReason as BreakpointHitStopReason).Breakpoint;
if (b.Number == 0) // specal case to keep compatibility with our test scripts.
{
CommandBase.WriteOutput("STOP: Breakpoint Hit");
}
else
{
CommandBase.WriteOutput(String.Format(CultureInfo.InvariantCulture, "STOP: Breakpoint {0} Hit", new Object[] { b.Number }));
}
}
else if (stopReasonType == typeof(ExceptionThrownStopReason))
{
ExceptionThrownStopReason ex = (ExceptionThrownStopReason)stopReason;
CommandBase.WriteOutput("STOP: Exception thrown");
PrintCurrentException();
if (Debugger.Options.StopOnExceptionEnhanced ||
ex.ExceptionEnhancedOn)
{
// when we are in ExceptionEnhanced mode, we print more information
CommandBase.WriteOutput("\tOffset: " + ex.Offset);
CommandBase.WriteOutput("\tEventType: " + ex.EventType);
CommandBase.WriteOutput("\tIntercept: " + (ex.Flags != 0));
}
}
else if (stopReasonType == typeof(UnhandledExceptionThrownStopReason))
{
CommandBase.WriteOutput("STOP: Unhandled Exception thrown");
PrintCurrentException();
CommandBase.WriteOutput("");
CommandBase.WriteOutput("This is unhandled exception, continuing will end the process");
}
else if (stopReasonType == typeof(ExceptionUnwindStopReason))
{
CommandBase.WriteOutput("STOP: Exception unwind");
CommandBase.WriteOutput("EventType: " + (stopReason as ExceptionUnwindStopReason).EventType);
}
else if (stopReasonType == typeof(ModuleLoadedStopReason))
{
CommandBase.WriteOutput("STOP: Module loaded: " + (stopReason as ModuleLoadedStopReason).Module.CorModule.Name);
}
else if (stopReasonType == typeof(AssemblyLoadedStopReason))
{
CommandBase.WriteOutput("STOP: Assembly loaded: " + (stopReason as AssemblyLoadedStopReason).Assembly.Name);
}
else if (stopReasonType == typeof(MDANotificationStopReason))
{
CorMDA mda = (stopReason as MDANotificationStopReason).CorMDA;
CommandBase.WriteOutput("STOP: MDANotification");
CommandBase.WriteOutput("Name=" + mda.Name);
CommandBase.WriteOutput("XML=" + mda.XML);
}
else if (stopReasonType == typeof(MDbgErrorStopReason))
{
Exception e = (stopReason as MDbgErrorStopReason).ExceptionThrown;
CommandBase.WriteOutput("STOP: MdbgError");
CommandBase.WriteOutput(FormatExceptionDiagnosticText(e));
}
else
{
CommandBase.WriteOutput("STOP " + Debugger.Processes.Active.StopReason);
}
}
if (!Debugger.Processes.Active.Threads.HaveActive)
{
return; // we won't try to show current location
}
MDbgThread thr = Debugger.Processes.Active.Threads.Active;
MDbgSourcePosition pos = thr.CurrentSourcePosition;
if (pos == null)
{
MDbgFrame f = thr.CurrentFrame;
if (f.IsManaged)
{
CorDebugMappingResult mappingResult;
uint ip;
f.CorFrame.GetIP(out ip, out mappingResult);
string s = "IP: " + ip + " @ " + f.Function.FullName + " - " + mappingResult;
CommandBase.WriteOutput(s);
}
else
{
CommandBase.WriteOutput("<Located in native code.>");
}
}
else
{
string fileLoc = FileLocator.GetFileLocation(pos.Path);
if (fileLoc == null)
{
// Using the full path makes debugging output inconsistant during automated test runs.
// For testing purposes we'll get rid of them.
//CommandBase.WriteOutput("located at line "+pos.Line + " in "+ pos.Path);
CommandBase.WriteOutput("located at line " + pos.Line + " in " + System.IO.Path.GetFileName(pos.Path));
}
else
{
IMDbgSourceFile file = SourceFileMgr.GetSourceFile(fileLoc);
string prefixStr = pos.Line.ToString(CultureInfo.InvariantCulture) + ":";
if (pos.Line < 1 || pos.Line > file.Count)
{
CommandBase.WriteOutput("located at line " + pos.Line + " in " + pos.Path);
throw new MDbgShellException(string.Format("Could not display current location; file {0} doesn't have line {1}.",
file.Path, pos.Line));
}
Debug.Assert((pos.Line > 0) && (pos.Line <= file.Count));
string lineContent = file[pos.Line];
if (pos.StartColumn == 0 && pos.EndColumn == 0 ||
!(CommandBase.Shell.IO is IMDbgIO2)) // or we don't have support for IMDbgIO2
{
// we don't know location in the line
CommandBase.Shell.IO.WriteOutput(MDbgOutputConstants.StdOutput, prefixStr + lineContent + "\n");
}
else
{
int hiStart;
if (pos.StartColumn > 0)
{
hiStart = pos.StartColumn - 1;
}
else
{
hiStart = 0;
}
int hiLen;
if (pos.EndColumn == 0 || // we don't know ending position
(pos.EndLine > pos.StartLine)) // multi-line statement, select whole 1st line
{
hiLen = lineContent.Length;
}
else
{
hiLen = pos.EndColumn - 1 - hiStart;
}
Debug.Assert(CommandBase.Shell.IO is IMDbgIO2); // see if condition above
(CommandBase.Shell.IO as IMDbgIO2).WriteOutput(MDbgOutputConstants.StdOutput, prefixStr + lineContent + "\n",
hiStart + prefixStr.Length, hiLen);
}
}
}
}
public virtual LocationState DisplayCurrentLocation()
{
var locationState = new LocationState(ProcessStateEnum.Stop);
if (!Debugger.Processes.HaveActive)
{
CommandBase.WriteOutput("STOP: Process Exited");
return(new LocationState(processState: ProcessStateEnum.Stop, message: "Process Exited"));
}
else
{
Debug.Assert(Debugger.Processes.HaveActive);
Object stopReason = Debugger.Processes.Active.StopReason;
Type stopReasonType = stopReason.GetType();
if (stopReasonType == typeof(StepCompleteStopReason))
{
// just ignore those
}
else if (stopReasonType == typeof(ThreadCreatedStopReason))
{
CommandBase.WriteOutput("STOP: Thread Created");
return(new LocationState(processState: ProcessStateEnum.Stop, message: "Thread Created"));
}
else if (stopReasonType == typeof(BreakpointHitStopReason))
{
MDbgBreakpoint b = (stopReason as BreakpointHitStopReason).Breakpoint;
if (b.Number == 0) // specal case to keep compatibility with our test scripts.
{
CommandBase.WriteOutput("STOP: Breakpoint Hit");
locationState = new LocationState(processState: ProcessStateEnum.Stop, message: "Breakpoint Hit");
}
else
{
CommandBase.WriteOutput(String.Format(CultureInfo.InvariantCulture, "STOP: Breakpoint {0} Hit", new Object[] { b.Number }));
locationState = new LocationState(processState: ProcessStateEnum.Stop, message: $"Breakpoint { b.Number } Hit");
}
}
else if (stopReasonType == typeof(ExceptionThrownStopReason))
{
ExceptionThrownStopReason ex = (ExceptionThrownStopReason)stopReason;
CommandBase.WriteOutput("STOP: Exception thrown");
PrintCurrentException();
if (Debugger.Options.StopOnExceptionEnhanced ||
ex.ExceptionEnhancedOn)
{
// when we are in ExceptionEnhanced mode, we print more information
CommandBase.WriteOutput("\tOffset: " + ex.Offset);
CommandBase.WriteOutput("\tEventType: " + ex.EventType);
CommandBase.WriteOutput("\tIntercept: " + (ex.Flags != 0));
}
locationState = new LocationState(processState: ProcessStateEnum.Stop, message: $"Exception thrown");
}
else if (stopReasonType == typeof(UnhandledExceptionThrownStopReason))
{
CommandBase.WriteOutput("STOP: Unhandled Exception thrown");
PrintCurrentException();
CommandBase.WriteOutput("");
CommandBase.WriteOutput("This is unhandled exception, continuing will end the process");
locationState = new LocationState(processState: ProcessStateEnum.Stop, message: $"Unhandled Exception thrown");
}
else if (stopReasonType == typeof(ExceptionUnwindStopReason))
{
CommandBase.WriteOutput("STOP: Exception unwind");
CommandBase.WriteOutput("EventType: " + (stopReason as ExceptionUnwindStopReason).EventType);
locationState = new LocationState(processState: ProcessStateEnum.Stop, message: $"Exception unwind");
}
else if (stopReasonType == typeof(ModuleLoadedStopReason))
{
CommandBase.WriteOutput("STOP: Module loaded: " + (stopReason as ModuleLoadedStopReason).Module.CorModule.Name);
locationState = new LocationState(processState: ProcessStateEnum.Stop, message: $"Module loaded: {(stopReason as ModuleLoadedStopReason).Module.CorModule.Name}");
}
else if (stopReasonType == typeof(AssemblyLoadedStopReason))
{
CommandBase.WriteOutput("STOP: Assembly loaded: " + (stopReason as AssemblyLoadedStopReason).Assembly.Name);
locationState = new LocationState(processState: ProcessStateEnum.Stop, message: $"Assembly loaded: {(stopReason as AssemblyLoadedStopReason).Assembly.Name}");
}
else if (stopReasonType == typeof(MDANotificationStopReason))
{
CorMDA mda = (stopReason as MDANotificationStopReason).CorMDA;
CommandBase.WriteOutput("STOP: MDANotification");
CommandBase.WriteOutput("Name=" + mda.Name);
CommandBase.WriteOutput("XML=" + mda.XML);
locationState = new LocationState(processState: ProcessStateEnum.Stop, message: $"MDANotification");
}
else if (stopReasonType == typeof(MDbgErrorStopReason))
{
Exception e = (stopReason as MDbgErrorStopReason).ExceptionThrown;
CommandBase.WriteOutput("STOP: MdbgError");
CommandBase.WriteOutput(FormatExceptionDiagnosticText(e));
locationState = new LocationState(processState: ProcessStateEnum.Stop, message: $"MdbgError");
}
else
{
CommandBase.WriteOutput("STOP " + Debugger.Processes.Active.StopReason);
locationState = new LocationState(processState: ProcessStateEnum.Stop, message: Debugger.Processes.Active.StopReason.ToString());
}
}
if (!Debugger.Processes.Active.Threads.HaveActive)
{
return(locationState);
}
MDbgThread thr = Debugger.Processes.Active.Threads.Active;
MDbgSourcePosition pos = thr.CurrentSourcePosition;
if (pos == null)
{
MDbgFrame f = thr.CurrentFrame;
if (f.IsManaged)
{
CorDebugMappingResult mappingResult;
uint offset;
f.CorFrame.GetIP(out offset, out mappingResult);
CommandBase.WriteOutput($"Offset:{offset} Function:{f.Function.FullName}");
locationState = new LocationState(processState: ProcessStateEnum.Running, message: $"Offset:{offset} Function:{f.Function.FullName}", function: f.Function.FullName);
}
else
{
CommandBase.WriteOutput("<Located in native code.>");
locationState = new LocationState(processState: ProcessStateEnum.Running, message: "<Located in native code.>");
}
}
else
{
string fileLoc = FileLocator.GetFileLocation(pos.Path);
MDbgFrame f = thr.CurrentFrame;
if (fileLoc == null)
{
// Using the full path makes debugging output inconsistant during automated test runs.
// For testing purposes we'll get rid of them.
//CommandBase.WriteOutput("located at line "+pos.Line + " in "+ pos.Path);
Console.WriteLine($@"ln:{pos.Line} col:{pos.StartColumn}:{pos.EndColumn} in [{f.Function.FullName}] - {pos.Path}");
locationState = new LocationState(processState: ProcessStateEnum.Running, function: f.Function.FullName, lineNumber: pos.Line, file: pos.Path);
}
else
{
IMDbgSourceFile file = SourceFileMgr.GetSourceFile(fileLoc);
string prefixStr = pos.Line.ToString(CultureInfo.InvariantCulture) + ":";
if (pos.Line < 1 || pos.Line > file.Count)
{
Console.WriteLine($@"ln:{pos.Line} col:{pos.StartColumn}:{pos.EndColumn} in [{f.Function.FullName}] - {pos.Path}");
locationState = new LocationState(processState: ProcessStateEnum.Running, function: f.Function.FullName, lineNumber: pos.Line, file: pos.Path);
throw new MDbgShellException(string.Format("Could not display current location; file {0} doesn't have line {1}.",
file.Path, pos.Line));
}
Debug.Assert((pos.Line > 0) && (pos.Line <= file.Count));
string lineContent = file[pos.Line];
if (pos.StartColumn == 0 && pos.EndColumn == 0 ||
!(CommandBase.Shell.IO is IMDbgIO2)) // or we don't have support for IMDbgIO2
{
// we don't know location in the line
CommandBase.Shell.IO.WriteOutput(MDbgOutputConstants.StdOutput, prefixStr + lineContent + "\n");
}
else
{
Console.WriteLine($@"ln:{pos.Line} col:{pos.StartColumn}:{pos.EndColumn} in [{f.Function.FullName}] - {pos.Path}");
Console.ForegroundColor = ConsoleColor.Yellow;
Console.WriteLine(lineContent);
Console.ResetColor();
locationState = new LocationState(processState: ProcessStateEnum.Running, function: f.Function.FullName, lineNumber: pos.Line, file: pos.Path, code: lineContent);
}
}
}
return(locationState);
}
// Highlight the statement for the given Source Position
protected void HighlightStatementAtPos(MDbgSourcePosition pos)
{
HighlightRangeWorker(
pos.StartLine, pos.StartColumn, pos.EndLine, pos.EndColumn,
this.MainForm.IsCurrentSourceActive);
}
protected override void OnRunWorker()
{
m_pos = null;
}
private void DisplaySource()
{
if (!_Shell.Debugger.Processes.HaveActive)
{
//CommandBase.WriteOutput("STOP: Process Exited");
return; // don't try to display current location
}
else
{
Object stopReason = _Shell.Debugger.Processes.Active.StopReason;
Type stopReasonType = stopReason.GetType();
if (stopReasonType == typeof(StepCompleteStopReason))
{
// just ignore those
}
}
if (!_Shell.Debugger.Processes.Active.Threads.HaveActive)
{
return; // we won't try to show current location
}
MDbgThread thr = _Shell.Debugger.Processes.Active.Threads.Active;
MDbgSourcePosition pos = thr.CurrentSourcePosition;
if (pos == null)
{
MDbgFrame f = thr.CurrentFrame;
if (f.IsManaged)
{
CorDebugMappingResult mappingResult;
uint ip;
f.CorFrame.GetIP(out ip, out mappingResult);
string s = "IP: " + ip + " @ " + f.Function.FullName + " - " + mappingResult;
CommandBase.WriteOutput(s);
}
else
{
CommandBase.WriteOutput("<Located in native code.>");
}
}
else
{
string fileLoc = _Shell.FileLocator.GetFileLocation(pos.Path);
if (fileLoc == null)
{
// Using the full path makes debugging output inconsistant during automated test runs.
// For testing purposes we'll get rid of them.
//CommandBase.WriteOutput("located at line "+pos.Line + " in "+ pos.Path);
CommandBase.WriteOutput("located at line " + pos.Line + " in " + System.IO.Path.GetFileName(pos.Path));
}
else
{
IMDbgSourceFile file = _Shell.SourceFileMgr.GetSourceFile(fileLoc);
string prefixStr = pos.Line.ToString(CultureInfo.InvariantCulture) + ":";
if (pos.Line < 1 || pos.Line > file.Count)
{
CommandBase.WriteOutput("located at line " + pos.Line + " in " + pos.Path);
throw new MDbgShellException(string.Format("Could not display current location; file {0} doesn't have line {1}.",
file.Path, pos.Line));
}
string lineContent = file[pos.Line];
DisplayFile(file.Path, pos.Line);
}
}
}
// Parse a function breakpoint.
ISequencePointResolver IBreakpointParser.ParseFunctionBreakpoint(string arguments)
{
Regex r;
Match m;
// maybe it's in the form:
// "b ~number"
r = new Regex(@"^~(\d+)$");
m = r.Match(arguments);
string symNum = m.Groups[1].Value;
if (symNum.Length > 0)
{
int intSymNum = Int32.Parse(symNum, CultureInfo.CurrentUICulture);
MdbgSymbol symbol = shell.SymbolCache.Retrieve(intSymNum);
return(new BreakpointFunctionLocation(
string.Format(CultureInfo.InvariantCulture, ":{0}", symbol.ModuleNumber),
symbol.ClassName,
symbol.Method,
symbol.Offset));
}
// maybe it's in the form:
// "b Mdbg.cs:34"
r = new Regex(@"^(\S+:)?(\d+)$");
m = r.Match(arguments);
string fname = m.Groups[1].Value;
string lineNo = m.Groups[2].Value;
int intLineNo = 0;
if (lineNo.Length > 0)
{
if (fname.Length > 0)
{
fname = fname.Substring(0, fname.Length - 1);
}
else
{
MDbgSourcePosition pos = null;
MDbgThread thr = shell.Debugger.Processes.Active.Threads.Active;
if (thr != null)
{
pos = thr.CurrentSourcePosition;
}
if (pos == null)
{
throw new Exception("Cannot determine current file");
}
fname = pos.Path;
}
intLineNo = Int32.Parse(lineNo, CultureInfo.CurrentUICulture);
return(new BreakpointLineNumberLocation(fname, intLineNo));
}
// now, to be valid, it must be in the form:
// "b mdbg!Mdbg.Main+3"
//
// Note that this case must be checked after the source-file case above because
// we want to assume that a number by itself is a source line, not a method name.
// This is the most general form, so check this case last. (Eg, "Mdbg.cs:34" could
// match as Class='MDbg', Method = 'cs:34'. )
//
// The underlying metadata is extremely flexible and allows almost anything to be
// in a method name, including spaces. Both C#, VB and MDbg's parsing are more restrictive.
// Note we allow most characters in class and method names, except those we are using for separators
// (+, ., :), <> since those are typically used to represent generics which we don't
// support, and spaces since those are usually command syntax errors.
// We exclude '*' for sanity reasons.
//
// Other caveats:
// - we must allow periods in the method name for methods like ".ctor".
// - be sure to allow $ character in the method and class names. Some compilers
// like to use this in function names.
// - Classes can't start with a number, but can include and end with numbers.
//
// Ideally we'd have a quoting mechanism and a more flexible parsing system to
// handle generics, method overloads, etc. across all of MDbg. At least we have the 'x'
// command and ~ shortcuts as a work-around.
r = new Regex(@"^" +
@"([^\!]+\!)?" + // optional module
@"((?:[^.*+:<> ]+\.)*)" + // optional class
@"([^*+:<>\d ][^*+:<> ]*)" + // method
@"(\+\d+)?" + // optional offset
@"$");
m = r.Match(arguments);
string module = m.Groups[1].Value;
string className = m.Groups[2].Value;
string method = m.Groups[3].Value;
string offset = m.Groups[4].Value;
int intOffset = 0;
if (method.Length > 0)
{
if (module.Length > 0)
{
module = module.Substring(0, module.Length - 1);
}
if (className.Length > 0)
{
// The class/module separator character is captured as part of className.
// Chop it off to get just the classname.
className = className.Substring(0, className.Length - 1);
}
if (offset.Length > 0)
{
intOffset = Int32.Parse(offset.Substring(1), CultureInfo.CurrentUICulture);
}
return(new BreakpointFunctionLocation(module, className, method, intOffset));
}
// We don't recognize the syntax. Return null. If the parser is chained, it gives
// our parent a chance to handle it.
return(null);
} // end function ParseFunctionBreakpoint