fnmatch method

int fnmatch(String pattern, String string, int flags)

Matches string against the shell wildcard pattern. Returns 0 if string matches pattern, FNM_NOMATCH if there is no match, or another non-zero value if there is an error.

Implementation

int fnmatch(String pattern, String string, int flags) {
  // Basic glob to regex conversion
  String regexPattern = '';

  for (int i = 0; i < pattern.length; i++) {
    String c = pattern[i];
    if (c == '*') {
      if ((flags & FNM_PATHNAME) != 0) {
        regexPattern += '[^/]*';
      } else {
        regexPattern += '.*';
      }
    } else if (c == '?') {
      if ((flags & FNM_PATHNAME) != 0) {
        regexPattern += '[^/]';
      } else {
        regexPattern += '.';
      }
    } else if (c == '[') {
      regexPattern += c;
      if (i + 1 < pattern.length && pattern[i + 1] == '!') {
        regexPattern += '^';
        i++;
      }
    } else if (c == ']') {
      regexPattern += c;
    } else if (c == '\\' && (flags & FNM_NOESCAPE) == 0) {
      if (i + 1 < pattern.length) {
        i++;
        regexPattern += RegExp.escape(pattern[i]);
      }
    } else {
      regexPattern += RegExp.escape(c);
    }
  }

  // Handle FNM_PERIOD
  if ((flags & FNM_PERIOD) != 0) {
    if (string.startsWith('.') && !pattern.startsWith('.')) {
      return FNM_NOMATCH;
    }
    if ((flags & FNM_PATHNAME) != 0) {
      // also check after slashes
      for (int i = 0; i < string.length - 1; i++) {
        if (string[i] == '/' && string[i+1] == '.') {
          // Need to see if pattern had a literal dot here. For simplicity, if we don't match it literally we might fail,
          // but a true parser would be more complex. Let's rely on regex match first, and if it matches, verify FNM_PERIOD.
          // Actually, if we just translate `*` to not match leading periods, it's easier.
        }
      }
    }
  }

  try {
    final regExp = RegExp('^$regexPattern\$');
    if (regExp.hasMatch(string)) {
      if ((flags & FNM_PERIOD) != 0 && (flags & FNM_PATHNAME) != 0) {
         // Post-validation for FNM_PERIOD with FNM_PATHNAME
         // e.g. "a/.b" should not match "a/*"
         final partsStr = string.split('/');
         final partsPat = pattern.split('/');
         // This is a naive check but works for many cases
         for (int i = 0; i < partsStr.length && i < partsPat.length; i++) {
           if (partsStr[i].startsWith('.') && !partsPat[i].startsWith('.')) {
             return FNM_NOMATCH;
           }
         }
      }
      return 0; // Success
    }
  } catch (e) {
    return -1; // General error
  }

  return FNM_NOMATCH;
}