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// Copyright 2020 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 fs
import (
"path"
)
// A GlobFS is a file system with a Glob method.
type GlobFS interface {
FS
// Glob returns the names of all files matching pattern,
// providing an implementation of the top-level
// Glob function.
Glob(pattern string) ([]string, error)
}
// 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 path.Match. The pattern may describe hierarchical names such as
// usr/*/bin/ed.
//
// Glob ignores file system errors such as I/O errors reading directories.
// The only possible returned error is path.ErrBadPattern, reporting that
// the pattern is malformed.
//
// If fs implements GlobFS, Glob calls fs.Glob.
// Otherwise, Glob uses ReadDir to traverse the directory tree
// and look for matches for the pattern.
func Glob(fsys FS, pattern string) (matches []string, err error) {
if fsys, ok := fsys.(GlobFS); ok {
return fsys.Glob(pattern)
}
// Check pattern is well-formed.
if _, err := path.Match(pattern, ""); err != nil {
return nil, err
}
if !hasMeta(pattern) {
if _, err = Stat(fsys, pattern); err != nil {
return nil, nil
}
return []string{pattern}, nil
}
dir, file := path.Split(pattern)
dir = cleanGlobPath(dir)
if !hasMeta(dir) {
return glob(fsys, dir, file, nil)
}
// Prevent infinite recursion. See issue 15879.
if dir == pattern {
return nil, path.ErrBadPattern
}
var m []string
m, err = Glob(fsys, dir)
if err != nil {
return
}
for _, d := range m {
matches, err = glob(fsys, d, file, matches)
if err != nil {
return
}
}
return
}
// cleanGlobPath prepares path for glob matching.
func cleanGlobPath(path string) string {
switch path {
case "":
return "."
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, returning the updated slice.
// If the directory cannot be opened, glob returns the existing matches.
// New matches are added in lexicographical order.
func glob(fs FS, dir, pattern string, matches []string) (m []string, e error) {
m = matches
infos, err := ReadDir(fs, dir)
if err != nil {
return // ignore I/O error
}
for _, info := range infos {
n := info.Name()
matched, err := path.Match(pattern, n)
if err != nil {
return m, err
}
if matched {
m = append(m, path.Join(dir, n))
}
}
return
}
// hasMeta reports whether path contains any of the magic characters
// recognized by path.Match.
func hasMeta(path string) bool {
for i := 0; i < len(path); i++ {
switch path[i] {
case '*', '?', '[', '\\':
return true
}
}
return false
}