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restic/vendor/github.com/pkg/sftp/match.go
2017-07-23 14:25:38 +02:00

296 lines
6.6 KiB
Go

package sftp
import (
"path"
"strings"
"unicode/utf8"
)
// ErrBadPattern indicates a globbing pattern was malformed.
var ErrBadPattern = path.ErrBadPattern
// Unix separator
const separator = "/"
// 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.
//
//
func Match(pattern, name string) (matched bool, err error) {
return path.Match(pattern, name)
}
// detect if byte(char) is path separator
func isPathSeparator(c byte) bool {
return string(c) == "/"
}
// 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 ?.
func matchChunk(chunk, s string) (rest string, ok bool, err 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:]
// We can't end right after '[', we're expecting at least
// a closing bracket and possibly a caret.
if len(chunk) == 0 {
err = ErrBadPattern
return
}
// possibly negated
negated := chunk[0] == '^'
if negated {
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
}
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 == negated {
return
}
case '?':
if isPathSeparator(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 rune, nchunk string, err 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
}
// Split splits path immediately following the final Separator,
// separating it into a directory and file name component.
// If there is no Separator in path, Split returns an empty dir
// and file set to path.
// The returned values have the property that path = dir+file.
func Split(path string) (dir, file string) {
i := len(path) - 1
for i >= 0 && !isPathSeparator(path[i]) {
i--
}
return path[:i+1], path[i+1:]
}
// 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.
func (c *Client) Glob(pattern string) (matches []string, err error) {
if !hasMeta(pattern) {
file, err := c.Lstat(pattern)
if err != nil {
return nil, nil
}
dir, _ := Split(pattern)
dir = cleanGlobPath(dir)
return []string{Join(dir, file.Name())}, nil
}
dir, file := Split(pattern)
dir = cleanGlobPath(dir)
if !hasMeta(dir) {
return c.glob(dir, file, nil)
}
// Prevent infinite recursion. See issue 15879.
if dir == pattern {
return nil, ErrBadPattern
}
var m []string
m, err = c.Glob(dir)
if err != nil {
return
}
for _, d := range m {
matches, err = c.glob(d, file, matches)
if err != nil {
return
}
}
return
}
// cleanGlobPath prepares path for glob matching.
func cleanGlobPath(path string) string {
switch path {
case "":
return "."
case string(separator):
// do nothing to the path
return path
default:
return 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 (c *Client) glob(dir, pattern string, matches []string) (m []string, e error) {
m = matches
fi, err := c.Stat(dir)
if err != nil {
return
}
if !fi.IsDir() {
return
}
names, err := c.ReadDir(dir)
if err != nil {
return
}
//sort.Strings(names)
for _, n := range names {
matched, err := Match(pattern, n.Name())
if err != nil {
return m, err
}
if matched {
m = append(m, Join(dir, n.Name()))
}
}
return
}
// Join joins any number of path elements into a single path, adding
// a Separator if necessary.
// all empty strings are ignored.
func Join(elem ...string) string {
return path.Join(elem...)
}
// hasMeta reports whether path contains any of the magic characters
// recognized by Match.
func hasMeta(path string) bool {
// TODO(niemeyer): Should other magic characters be added here?
return strings.ContainsAny(path, "*?[")
}