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Diffstat (limited to 'src/path/filepath/match.go')
-rw-r--r-- | src/path/filepath/match.go | 309 |
1 files changed, 309 insertions, 0 deletions
diff --git a/src/path/filepath/match.go b/src/path/filepath/match.go new file mode 100644 index 000000000..ecc07aa5d --- /dev/null +++ b/src/path/filepath/match.go @@ -0,0 +1,309 @@ +// Copyright 2010 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package filepath + +import ( + "errors" + "os" + "runtime" + "sort" + "strings" + "unicode/utf8" +) + +// ErrBadPattern indicates a globbing pattern was malformed. +var ErrBadPattern = errors.New("syntax error in pattern") + +// Match returns true if 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) + if star && chunk == "" { + // Trailing * matches rest of string unless it has a /. + return strings.Index(name, string(Separator)) < 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] != Separator; 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 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 '\\': + if runtime.GOOS != "windows" { + // 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 s[0] == Separator { + return + } + _, n := utf8.DecodeRuneInString(s) + s = s[n:] + chunk = chunk[1:] + + case '\\': + if runtime.GOOS != "windows" { + 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] == '\\' && 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. +func Glob(pattern string) (matches []string, err error) { + if !hasMeta(pattern) { + if _, err = os.Lstat(pattern); err != nil { + return nil, nil + } + return []string{pattern}, nil + } + + dir, file := Split(pattern) + switch dir { + case "": + dir = "." + case string(Separator): + // nothing + default: + dir = dir[0 : len(dir)-1] // chop off trailing separator + } + + if !hasMeta(dir) { + return glob(dir, file, nil) + } + + 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 +} + +// 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 + } + if !fi.IsDir() { + return + } + d, err := os.Open(dir) + if err != nil { + return + } + 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 returns true if 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.IndexAny(path, "*?[") >= 0 +} |