package filter import ( "path/filepath" "strings" "github.com/restic/restic/internal/errors" ) // ErrBadString is returned when Match is called with the empty string as the // second argument. var ErrBadString = errors.New("filter.Match: string is empty") // Pattern represents a preparsed filter pattern type Pattern []string func prepareStr(str string) ([]string, error) { if str == "" { return nil, ErrBadString } // convert file path separator to '/' if filepath.Separator != '/' { str = strings.Replace(str, string(filepath.Separator), "/", -1) } return strings.Split(str, "/"), nil } func preparePattern(pattern string) Pattern { pattern = filepath.Clean(pattern) // convert file path separator to '/' if filepath.Separator != '/' { pattern = strings.Replace(pattern, string(filepath.Separator), "/", -1) } return strings.Split(pattern, "/") } // Match returns true if str matches the pattern. When the pattern is // malformed, filepath.ErrBadPattern is returned. The empty pattern matches // everything, when str is the empty string ErrBadString is returned. // // Pattern can be a combination of patterns suitable for filepath.Match, joined // by filepath.Separator. // // In addition patterns suitable for filepath.Match, pattern accepts a // recursive wildcard '**', which greedily matches an arbitrary number of // intermediate directories. func Match(pattern, str string) (matched bool, err error) { if pattern == "" { return true, nil } patterns := preparePattern(pattern) strs, err := prepareStr(str) if err != nil { return false, err } return match(patterns, strs) } // ChildMatch returns true if children of str can match the pattern. When the pattern is // malformed, filepath.ErrBadPattern is returned. The empty pattern matches // everything, when str is the empty string ErrBadString is returned. // // Pattern can be a combination of patterns suitable for filepath.Match, joined // by filepath.Separator. // // In addition patterns suitable for filepath.Match, pattern accepts a // recursive wildcard '**', which greedily matches an arbitrary number of // intermediate directories. func ChildMatch(pattern, str string) (matched bool, err error) { if pattern == "" { return true, nil } patterns := preparePattern(pattern) strs, err := prepareStr(str) if err != nil { return false, err } return childMatch(patterns, strs) } func childMatch(patterns Pattern, strs []string) (matched bool, err error) { if patterns[0] != "" { // relative pattern can always be nested down return true, nil } ok, pos := hasDoubleWildcard(patterns) if ok && len(strs) >= pos { // cut off at the double wildcard strs = strs[:pos] } // match path against absolute pattern prefix l := 0 if len(strs) > len(patterns) { l = len(patterns) } else { l = len(strs) } return match(patterns[0:l], strs) } func hasDoubleWildcard(list Pattern) (ok bool, pos int) { for i, item := range list { if item == "**" { return true, i } } return false, 0 } func match(patterns Pattern, strs []string) (matched bool, err error) { if ok, pos := hasDoubleWildcard(patterns); ok { // gradually expand '**' into separate wildcards newPat := make(Pattern, len(strs)) // copy static prefix once copy(newPat, patterns[:pos]) for i := 0; i <= len(strs)-len(patterns)+1; i++ { // limit to static prefix and already appended '*' newPat := newPat[:pos+i] // in the first iteration the wildcard expands to nothing if i > 0 { newPat[pos+i-1] = "*" } newPat = append(newPat, patterns[pos+1:]...) matched, err := match(newPat, strs) if err != nil { return false, err } if matched { return true, nil } } return false, nil } if len(patterns) == 0 && len(strs) == 0 { return true, nil } if len(patterns) <= len(strs) { maxOffset := len(strs) - len(patterns) // special case absolute patterns if patterns[0] == "" { maxOffset = 0 } outer: for offset := maxOffset; offset >= 0; offset-- { for i := len(patterns) - 1; i >= 0; i-- { ok, err := filepath.Match(patterns[i], strs[offset+i]) if err != nil { return false, errors.Wrap(err, "Match") } if !ok { continue outer } } return true, nil } } return false, nil } // ParsePatterns prepares a list of patterns for use with List. func ParsePatterns(patterns []string) []Pattern { patpat := make([]Pattern, 0) for _, pat := range patterns { if pat == "" { continue } pats := preparePattern(pat) patpat = append(patpat, pats) } return patpat } // List returns true if str matches one of the patterns. Empty patterns are ignored. func List(patterns []Pattern, str string) (matched bool, childMayMatch bool, err error) { if len(patterns) == 0 { return false, false, nil } strs, err := prepareStr(str) if err != nil { return false, false, err } for _, pat := range patterns { m, err := match(pat, strs) if err != nil { return false, false, err } c, err := childMatch(pat, strs) if err != nil { return false, false, err } matched = matched || m childMayMatch = childMayMatch || c if matched && childMayMatch { return true, true, nil } } return matched, childMayMatch, nil }