static Pattern convertGlob()

in org.eclipse.jgit/src/org/eclipse/jgit/ignore/internal/Strings.java [246:418]
153 lines of code
56 McCabe index (conditional complexity)

	static Pattern convertGlob(String pattern) throws InvalidPatternException {
		if (UNSUPPORTED.matcher(pattern).find())
			throw new InvalidPatternException(
					"Collating symbols [[.a.]] or equivalence class expressions [[=a=]] are not supported", //$NON-NLS-1$
					pattern);

		StringBuilder sb = new StringBuilder(pattern.length());

		int in_brackets = 0;
		boolean seenEscape = false;
		boolean ignoreLastBracket = false;
		boolean in_char_class = false;
		// 6 is the length of the longest posix char class "xdigit"
		char[] charClass = new char[6];

		for (int i = 0; i < pattern.length(); i++) {
			final char c = pattern.charAt(i);
			switch (c) {

			case '*':
				if (seenEscape || in_brackets > 0)
					sb.append(c);
				else
					sb.append('.').append(c);
				break;

			case '(': // fall-through
			case ')': // fall-through
			case '{': // fall-through
			case '}': // fall-through
			case '+': // fall-through
			case '$': // fall-through
			case '^': // fall-through
			case '|':
				if (seenEscape || in_brackets > 0)
					sb.append(c);
				else
					sb.append('\\').append(c);
				break;

			case '.':
				if (seenEscape)
					sb.append(c);
				else
					sb.append('\\').append('.');
				break;

			case '?':
				if (seenEscape || in_brackets > 0)
					sb.append(c);
				else
					sb.append('.');
				break;

			case ':':
				if (in_brackets > 0)
					if (lookBehind(sb) == '['
							&& isLetter(lookAhead(pattern, i)))
						in_char_class = true;
				sb.append(':');
				break;

			case '-':
				if (in_brackets > 0) {
					if (lookAhead(pattern, i) == ']')
						sb.append('\\').append(c);
					else
						sb.append(c);
				} else
					sb.append('-');
				break;

			case '\\':
				if (in_brackets > 0) {
					char lookAhead = lookAhead(pattern, i);
					if (lookAhead == ']' || lookAhead == '[')
						ignoreLastBracket = true;
				} else {
					//
					char lookAhead = lookAhead(pattern, i);
					if (lookAhead != '\\' && lookAhead != '['
							&& lookAhead != '?' && lookAhead != '*'
							&& lookAhead != ' ' && lookBehind(sb) != '\\') {
						break;
					}
				}
				sb.append(c);
				break;

			case '[':
				if (in_brackets > 0) {
					if (!seenEscape) {
						sb.append('\\');
					}
					sb.append('[');
					ignoreLastBracket = true;
				} else {
					if (!seenEscape) {
						in_brackets++;
						ignoreLastBracket = false;
					}
					sb.append('[');
				}
				break;

			case ']':
				if (seenEscape) {
					sb.append(']');
					ignoreLastBracket = true;
					break;
				}
				if (in_brackets <= 0) {
					sb.append('\\').append(']');
					ignoreLastBracket = true;
					break;
				}
				char lookBehind = lookBehind(sb);
				if ((lookBehind == '[' && !ignoreLastBracket)
						|| lookBehind == '^') {
					sb.append('\\');
					sb.append(']');
					ignoreLastBracket = true;
				} else {
					ignoreLastBracket = false;
					if (!in_char_class) {
						in_brackets--;
						sb.append(']');
					} else {
						in_char_class = false;
						String charCl = checkPosixCharClass(charClass);
						// delete last \[:: chars and set the pattern
						if (charCl != null) {
							sb.setLength(sb.length() - 4);
							sb.append(charCl);
						}
						reset(charClass);
					}
				}
				break;

			case '!':
				if (in_brackets > 0) {
					if (lookBehind(sb) == '[')
						sb.append('^');
					else
						sb.append(c);
				} else
					sb.append(c);
				break;

			default:
				if (in_char_class)
					setNext(charClass, c);
				else
					sb.append(c);
				break;
			} // end switch

			seenEscape = c == '\\';

		} // end for

		if (in_brackets > 0)
			throw new InvalidPatternException("Not closed bracket?", pattern); //$NON-NLS-1$
		try {
			return Pattern.compile(sb.toString(), Pattern.DOTALL);
		} catch (PatternSyntaxException e) {
			throw new InvalidPatternException(
					MessageFormat.format(JGitText.get().invalidIgnoreRule,
							pattern),
					pattern, e);
		}
	}