diff options
Diffstat (limited to 'libgo/go/path/match.go')
| -rw-r--r-- | libgo/go/path/match.go | 278 |
1 files changed, 278 insertions, 0 deletions
diff --git a/libgo/go/path/match.go b/libgo/go/path/match.go new file mode 100644 index 000000000..dd3422c42 --- /dev/null +++ b/libgo/go/path/match.go @@ -0,0 +1,278 @@ +package path + +import ( + "os" + "sort" + "strings" + "utf8" +) + +var ErrBadPattern = os.NewError("syntax error in pattern") + +// Match returns true if name matches the shell file name pattern. +// The syntax used by pattern is: +// +// pattern: +// { term } +// term: +// '*' matches any sequence of non-/ characters +// '?' matches any single non-/ character +// '[' [ '^' ] { character-range } ']' +// character class (must be non-empty) +// c matches character c (c != '*', '?', '\\', '[') +// '\\' c matches character c +// +// character-range: +// c matches character c (c != '\\', '-', ']') +// '\\' c matches character c +// lo '-' hi matches character c for lo <= c <= hi +// +// Match requires pattern to match all of name, not just a substring. +// The only possible error return is when pattern is malformed. +// +func Match(pattern, name string) (matched bool, err os.Error) { +Pattern: + for len(pattern) > 0 { + var star bool + var chunk string + star, chunk, pattern = scanChunk(pattern) + if star && chunk == "" { + // Trailing * matches rest of string unless it has a /. + return strings.Index(name, "/") < 0, nil + } + // Look for match at current position. + t, ok, err := matchChunk(chunk, name) + // if we're the last chunk, make sure we've exhausted the name + // otherwise we'll give a false result even if we could still match + // using the star + if ok && (len(t) == 0 || len(pattern) > 0) { + name = t + continue + } + if err != nil { + return false, err + } + if star { + // Look for match skipping i+1 bytes. + // Cannot skip /. + for i := 0; i < len(name) && name[i] != '/'; i++ { + t, ok, err := matchChunk(chunk, name[i+1:]) + if ok { + // if we're the last chunk, make sure we exhausted the name + if len(pattern) == 0 && len(t) > 0 { + continue + } + name = t + continue Pattern + } + if err != nil { + return false, err + } + } + } + return false, nil + } + return len(name) == 0, nil +} + +// scanChunk gets the next section of pattern, which is a non-star string +// possibly preceded by a star. +func scanChunk(pattern string) (star bool, chunk, rest string) { + for len(pattern) > 0 && pattern[0] == '*' { + pattern = pattern[1:] + star = true + } + inrange := false + var i int +Scan: + for i = 0; i < len(pattern); i++ { + switch pattern[i] { + case '\\': + // error check handled in matchChunk: bad pattern. + if i+1 < len(pattern) { + i++ + } + continue + case '[': + inrange = true + case ']': + inrange = false + case '*': + if !inrange { + break Scan + } + } + } + return star, pattern[0:i], pattern[i:] +} + +// matchChunk checks whether chunk matches the beginning of s. +// If so, it returns the remainder of s (after the match). +// Chunk is all single-character operators: literals, char classes, and ?. +func matchChunk(chunk, s string) (rest string, ok bool, err os.Error) { + for len(chunk) > 0 { + if len(s) == 0 { + return + } + switch chunk[0] { + case '[': + // character class + r, n := utf8.DecodeRuneInString(s) + s = s[n:] + chunk = chunk[1:] + // possibly negated + notNegated := true + if len(chunk) > 0 && chunk[0] == '^' { + notNegated = false + chunk = chunk[1:] + } + // parse all ranges + match := false + nrange := 0 + for { + if len(chunk) > 0 && chunk[0] == ']' && nrange > 0 { + chunk = chunk[1:] + break + } + var lo, hi int + if lo, chunk, err = getEsc(chunk); err != nil { + return + } + hi = lo + if chunk[0] == '-' { + if hi, chunk, err = getEsc(chunk[1:]); err != nil { + return + } + } + if lo <= r && r <= hi { + match = true + } + nrange++ + } + if match != notNegated { + return + } + + case '?': + if s[0] == '/' { + return + } + _, n := utf8.DecodeRuneInString(s) + s = s[n:] + chunk = chunk[1:] + + case '\\': + chunk = chunk[1:] + if len(chunk) == 0 { + err = ErrBadPattern + return + } + fallthrough + + default: + if chunk[0] != s[0] { + return + } + s = s[1:] + chunk = chunk[1:] + } + } + return s, true, nil +} + +// getEsc gets a possibly-escaped character from chunk, for a character class. +func getEsc(chunk string) (r int, nchunk string, err os.Error) { + if len(chunk) == 0 || chunk[0] == '-' || chunk[0] == ']' { + err = ErrBadPattern + return + } + if chunk[0] == '\\' { + chunk = chunk[1:] + if len(chunk) == 0 { + err = ErrBadPattern + return + } + } + r, n := utf8.DecodeRuneInString(chunk) + if r == utf8.RuneError && n == 1 { + err = ErrBadPattern + } + nchunk = chunk[n:] + if len(nchunk) == 0 { + err = ErrBadPattern + } + return +} + +// Glob returns the names of all files matching pattern or nil +// if there is no matching file. The syntax of patterns is the same +// as in Match. The pattern may describe hierarchical names such as +// /usr/*/bin/ed. +// +func Glob(pattern string) (matches []string) { + if !hasMeta(pattern) { + if _, err := os.Stat(pattern); err == nil { + return []string{pattern} + } + return nil + } + + dir, file := Split(pattern) + switch dir { + case "": + dir = "." + case "/": + // nothing + default: + dir = dir[0 : len(dir)-1] // chop off trailing '/' + } + + if hasMeta(dir) { + for _, d := range Glob(dir) { + matches = glob(d, file, matches) + } + } else { + return glob(dir, file, nil) + } + return matches +} + +// glob searches for files matching pattern in the directory dir +// and appends them to matches. +func glob(dir, pattern string, matches []string) []string { + fi, err := os.Stat(dir) + if err != nil { + return nil + } + if !fi.IsDirectory() { + return matches + } + d, err := os.Open(dir, os.O_RDONLY, 0666) + if err != nil { + return nil + } + defer d.Close() + + names, err := d.Readdirnames(-1) + if err != nil { + return nil + } + sort.SortStrings(names) + + for _, n := range names { + matched, err := Match(pattern, n) + if err != nil { + return matches + } + if matched { + matches = append(matches, Join(dir, n)) + } + } + return matches +} + +// hasMeta returns true if path contains any of the magic characters +// recognized by Match. +func hasMeta(path string) bool { + return strings.IndexAny(path, "*?[") != -1 +} |