Source: match.go in package path/filepath


package filepath

import (
	"errors"
	"os"
	"runtime"
	"sort"
	"strings"
	"unicode/utf8"
)

ErrBadPattern indicates a pattern was malformed.

var ErrBadPattern = errors.New("syntax error in pattern")

Match reports whether name matches the shell file name pattern. The pattern syntax is: pattern: { term } term: '*' matches any sequence of non-Separator characters '?' matches any single non-Separator 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 returned error is ErrBadPattern, when pattern is malformed. On Windows, escaping is disabled. Instead, '\\' is treated as path separator.

func Match(pattern, name string) (matched bool, err error) {
Pattern:
	for len(pattern) > 0 {
		var star bool
		var chunk string
		star, chunk, pattern = scanChunk(pattern)

Trailing * matches rest of string unless it has a /.

			return !strings.Contains(name, string(Separator)), nil

Look for match at current position.

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
		}

Look for match skipping i+1 bytes. Cannot skip /.

			for i := 0; i < len(name) && name[i] != Separator; i++ {
				t, ok, err := matchChunk(chunk, name[i+1:])

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 segment 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++
				}
			}
		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 ?.

failed records whether the match has failed. After the match fails, the loop continues on processing chunk, checking that the pattern is well-formed but no longer reading s.

	failed := false
	for len(chunk) > 0 {
		if !failed && len(s) == 0 {
			failed = true
		}
		switch chunk[0] {

character class

			var r rune
			if !failed {
				var n int
				r, n = utf8.DecodeRuneInString(s)
				s = s[n:]
			}

possibly negated

			negated := false
			if len(chunk) > 0 && chunk[0] == '^' {
				negated = true
				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 rune
				if lo, chunk, err = getEsc(chunk); err != nil {
					return "", false, err
				}
				hi = lo
				if chunk[0] == '-' {
					if hi, chunk, err = getEsc(chunk[1:]); err != nil {
						return "", false, err
					}
				}
				if lo <= r && r <= hi {
					match = true
				}
				nrange++
			}
			if match == negated {
				failed = true
			}

		case '?':
			if !failed {
				if s[0] == Separator {
					failed = true
				}
				_, n := utf8.DecodeRuneInString(s)
				s = s[n:]
			}
			chunk = chunk[1:]

		case '\\':
			if runtime.GOOS != "windows" {
				chunk = chunk[1:]
				if len(chunk) == 0 {
					return "", false, ErrBadPattern
				}
			}
			fallthrough

		default:
			if !failed {
				if chunk[0] != s[0] {
					failed = true
				}
				s = s[1:]
			}
			chunk = chunk[1:]
		}
	}
	if failed {
		return "", false, nil
	}
	return s, true, nil
}

getEsc gets a possibly-escaped character from chunk, for a character class.

func getEsc(chunk string) (r rune, nchunk string, err error) {
	if len(chunk) == 0 || chunk[0] == '-' || chunk[0] == ']' {
		err = ErrBadPattern
		return
	}
	if chunk[0] == '\\' && runtime.GOOS != "windows" {
		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 (assuming the Separator is '/'). Glob ignores file system errors such as I/O errors reading directories. The only possible returned error is ErrBadPattern, when pattern is malformed.

Check pattern is well-formed.

	if _, err := Match(pattern, ""); err != nil {
		return nil, err
	}
	if !hasMeta(pattern) {
		if _, err = os.Lstat(pattern); err != nil {
			return nil, nil
		}
		return []string{pattern}, nil
	}

	dir, file := Split(pattern)
	volumeLen := 0
	if runtime.GOOS == "windows" {
		volumeLen, dir = cleanGlobPathWindows(dir)
	} else {
		dir = cleanGlobPath(dir)
	}

	if !hasMeta(dir[volumeLen:]) {
		return glob(dir, file, nil)
	}

Prevent infinite recursion. See issue 15879.

	if dir == pattern {
		return nil, ErrBadPattern
	}

	var m []string
	m, err = Glob(dir)
	if err != nil {
		return
	}
	for _, d := range m {
		matches, err = glob(d, file, matches)
		if err != nil {
			return
		}
	}
	return
}

cleanGlobPath prepares path for glob matching.

func cleanGlobPath(path string) string {
	switch path {
	case "":
		return "."

do nothing to the path

		return path
	default:
		return path[0 : len(path)-1] // chop off trailing separator
	}
}

cleanGlobPathWindows is windows version of cleanGlobPath.

func cleanGlobPathWindows(path string) (prefixLen int, cleaned string) {
	vollen := volumeNameLen(path)
	switch {
	case path == "":
		return 0, "."

do nothing to the path

		return vollen + 1, path
	case vollen == len(path) && len(path) == 2: // C:
		return vollen, path + "." // convert C: into C:.
	default:
		if vollen >= len(path) {
			vollen = len(path) - 1
		}
		return vollen, path[0 : len(path)-1] // chop off trailing separator
	}
}

glob searches for files matching pattern in the directory dir and appends them to matches. If the directory cannot be opened, it returns the existing matches. New matches are added in lexicographical order.

func glob(dir, pattern string, matches []string) (m []string, e error) {
	m = matches
	fi, err := os.Stat(dir)
	if err != nil {
		return // ignore I/O error
	}
	if !fi.IsDir() {
		return // ignore I/O error
	}
	d, err := os.Open(dir)
	if err != nil {
		return // ignore I/O error
	}
	defer d.Close()

	names, _ := d.Readdirnames(-1)
	sort.Strings(names)

	for _, n := range names {
		matched, err := Match(pattern, n)
		if err != nil {
			return m, err
		}
		if matched {
			m = append(m, Join(dir, n))
		}
	}
	return
}

hasMeta reports whether path contains any of the magic characters recognized by Match.

func hasMeta(path string) bool {
	magicChars := `*?[`
	if runtime.GOOS != "windows" {
		magicChars = `*?[\`
	}
	return strings.ContainsAny(path, magicChars)