AsmHighlighter.AsmHighlighterLanguageService.ValidateBreakpointLocation C# (CSharp) Method

        public override int ValidateBreakpointLocation(IVsTextBuffer buffer, int line, int col, TextSpan[] pCodeSpan)
        {
            // Return noimpl by default
            int retval = VSConstants.E_NOTIMPL;

            if (pCodeSpan != null)
            {
                // Make sure the span is set to at least the current
                // position by default.
                pCodeSpan[0].iStartLine = line;
                pCodeSpan[0].iStartIndex = 0;
                pCodeSpan[0].iEndLine = line;
                pCodeSpan[0].iEndIndex = col;
            }

            if (buffer != null)
            {
                IVsTextLines textLines = buffer as IVsTextLines;
                if (textLines != null)
                {
                    AsmHighlighterScanner scanner = AsmHighlighterScannerFactory.GetScanner(textLines);
                    Scanner lexer = scanner.Lexer;

                    int maxColumn;
                    textLines.GetLengthOfLine(line, out maxColumn);
                    string lineToParse;
                    textLines.GetLineText(line, 0, line, maxColumn, out lineToParse);

                    // Setup token scanner
                    lexer.SetSource(lineToParse, 0);

                    int state = 0;
                    int start, end;

                    AsmHighlighterToken token = (AsmHighlighterToken)lexer.GetNext(ref state, out start, out end);

                    // Set Not a valid breakpoint
                    retval = VSConstants.S_FALSE;
                    switch (token)
                    {
                        case AsmHighlighterToken.INSTRUCTION:
                        case AsmHighlighterToken.FPUPROCESSOR:
                        case AsmHighlighterToken.SIMDPROCESSOR:
                            if (pCodeSpan != null)
                            {
                                // Breakpoint covers the whole line (including comment)
                                pCodeSpan[0].iEndIndex = maxColumn;
                            }
                            // Set valid breakpoint
                            retval = VSConstants.S_OK;
                            break;
                    }
                }
            }
            return retval;
        }