1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
|
// Copyright 2009 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.
// The path package implements utility routines for manipulating
// slash-separated filename paths.
package path
import (
"io/ioutil"
"os"
"strings"
)
// Clean returns the shortest path name equivalent to path
// by purely lexical processing. It applies the following rules
// iteratively until no further processing can be done:
//
// 1. Replace multiple slashes with a single slash.
// 2. Eliminate each . path name element (the current directory).
// 3. Eliminate each inner .. path name element (the parent directory)
// along with the non-.. element that precedes it.
// 4. Eliminate .. elements that begin a rooted path:
// that is, replace "/.." by "/" at the beginning of a path.
//
// If the result of this process is an empty string, Clean
// returns the string ".".
//
// See also Rob Pike, ``Lexical File Names in Plan 9 or
// Getting Dot-Dot right,''
// http://plan9.bell-labs.com/sys/doc/lexnames.html
func Clean(path string) string {
if path == "" {
return "."
}
rooted := path[0] == '/'
n := len(path)
// Invariants:
// reading from path; r is index of next byte to process.
// writing to buf; w is index of next byte to write.
// dotdot is index in buf where .. must stop, either because
// it is the leading slash or it is a leading ../../.. prefix.
buf := []byte(path)
r, w, dotdot := 0, 0, 0
if rooted {
r, w, dotdot = 1, 1, 1
}
for r < n {
switch {
case path[r] == '/':
// empty path element
r++
case path[r] == '.' && (r+1 == n || path[r+1] == '/'):
// . element
r++
case path[r] == '.' && path[r+1] == '.' && (r+2 == n || path[r+2] == '/'):
// .. element: remove to last /
r += 2
switch {
case w > dotdot:
// can backtrack
w--
for w > dotdot && buf[w] != '/' {
w--
}
case !rooted:
// cannot backtrack, but not rooted, so append .. element.
if w > 0 {
buf[w] = '/'
w++
}
buf[w] = '.'
w++
buf[w] = '.'
w++
dotdot = w
}
default:
// real path element.
// add slash if needed
if rooted && w != 1 || !rooted && w != 0 {
buf[w] = '/'
w++
}
// copy element
for ; r < n && path[r] != '/'; r++ {
buf[w] = path[r]
w++
}
}
}
// Turn empty string into "."
if w == 0 {
buf[w] = '.'
w++
}
return string(buf[0:w])
}
// Split splits path immediately following the final path 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.
func Split(path string) (dir, file string) {
i := strings.LastIndexAny(path, PathSeps)
return path[:i+1], path[i+1:]
}
// Join joins any number of path elements into a single path, adding a
// separating slash if necessary. All empty strings are ignored.
func Join(elem ...string) string {
for i, e := range elem {
if e != "" {
return Clean(strings.Join(elem[i:], "/"))
}
}
return ""
}
// Ext returns the file name extension used by path.
// The extension is the suffix beginning at the final dot
// in the final slash-separated element of path;
// it is empty if there is no dot.
func Ext(path string) string {
for i := len(path) - 1; i >= 0 && path[i] != '/'; i-- {
if path[i] == '.' {
return path[i:]
}
}
return ""
}
// Visitor methods are invoked for corresponding file tree entries
// visited by Walk. The parameter path is the full path of f relative
// to root.
type Visitor interface {
VisitDir(path string, f *os.FileInfo) bool
VisitFile(path string, f *os.FileInfo)
}
func walk(path string, f *os.FileInfo, v Visitor, errors chan<- os.Error) {
if !f.IsDirectory() {
v.VisitFile(path, f)
return
}
if !v.VisitDir(path, f) {
return // skip directory entries
}
list, err := ioutil.ReadDir(path)
if err != nil {
if errors != nil {
errors <- err
}
}
for _, e := range list {
walk(Join(path, e.Name), e, v, errors)
}
}
// Walk walks the file tree rooted at root, calling v.VisitDir or
// v.VisitFile for each directory or file in the tree, including root.
// If v.VisitDir returns false, Walk skips the directory's entries;
// otherwise it invokes itself for each directory entry in sorted order.
// An error reading a directory does not abort the Walk.
// If errors != nil, Walk sends each directory read error
// to the channel. Otherwise Walk discards the error.
func Walk(root string, v Visitor, errors chan<- os.Error) {
f, err := os.Lstat(root)
if err != nil {
if errors != nil {
errors <- err
}
return // can't progress
}
walk(root, f, v, errors)
}
// Base returns the last path element of the slash-separated name.
// Trailing slashes are removed before extracting the last element. If the name is
// empty, "." is returned. If it consists entirely of slashes, "/" is returned.
func Base(name string) string {
if name == "" {
return "."
}
// Strip trailing slashes.
for len(name) > 0 && name[len(name)-1] == '/' {
name = name[0 : len(name)-1]
}
// Find the last element
if i := strings.LastIndex(name, "/"); i >= 0 {
name = name[i+1:]
}
// If empty now, it had only slashes.
if name == "" {
return "/"
}
return name
}
// IsAbs returns true if the path is absolute.
func IsAbs(path string) bool {
// TODO: Add Windows support
return strings.HasPrefix(path, "/")
}
|
