forked from golang/go
-
Notifications
You must be signed in to change notification settings - Fork 0
/
type.go
202 lines (181 loc) · 5.16 KB
/
type.go
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
// 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 mime implements parts of the MIME spec.
package mime
import (
"fmt"
"sort"
"strings"
"sync"
)
var (
mimeTypes sync.Map // map[string]string; ".Z" => "application/x-compress"
mimeTypesLower sync.Map // map[string]string; ".z" => "application/x-compress"
// extensions maps from MIME type to list of lowercase file
// extensions: "image/jpeg" => [".jpg", ".jpeg"]
extensionsMu sync.Mutex // Guards stores (but not loads) on extensions.
extensions sync.Map // map[string][]string; slice values are append-only.
)
func clearSyncMap(m *sync.Map) {
m.Range(func(k, _ any) bool {
m.Delete(k)
return true
})
}
// setMimeTypes is used by initMime's non-test path, and by tests.
func setMimeTypes(lowerExt, mixExt map[string]string) {
clearSyncMap(&mimeTypes)
clearSyncMap(&mimeTypesLower)
clearSyncMap(&extensions)
for k, v := range lowerExt {
mimeTypesLower.Store(k, v)
}
for k, v := range mixExt {
mimeTypes.Store(k, v)
}
extensionsMu.Lock()
defer extensionsMu.Unlock()
for k, v := range lowerExt {
justType, _, err := ParseMediaType(v)
if err != nil {
panic(err)
}
var exts []string
if ei, ok := extensions.Load(justType); ok {
exts = ei.([]string)
}
extensions.Store(justType, append(exts, k))
}
}
var builtinTypesLower = map[string]string{
".avif": "image/avif",
".css": "text/css; charset=utf-8",
".gif": "image/gif",
".htm": "text/html; charset=utf-8",
".html": "text/html; charset=utf-8",
".jpeg": "image/jpeg",
".jpg": "image/jpeg",
".js": "text/javascript; charset=utf-8",
".json": "application/json",
".mjs": "text/javascript; charset=utf-8",
".pdf": "application/pdf",
".png": "image/png",
".svg": "image/svg+xml",
".wasm": "application/wasm",
".webp": "image/webp",
".xml": "text/xml; charset=utf-8",
}
var once sync.Once // guards initMime
var testInitMime, osInitMime func()
func initMime() {
if fn := testInitMime; fn != nil {
fn()
} else {
setMimeTypes(builtinTypesLower, builtinTypesLower)
osInitMime()
}
}
// TypeByExtension returns the MIME type associated with the file extension ext.
// The extension ext should begin with a leading dot, as in ".html".
// When ext has no associated type, TypeByExtension returns "".
//
// Extensions are looked up first case-sensitively, then case-insensitively.
//
// The built-in table is small but on unix it is augmented by the local
// system's MIME-info database or mime.types file(s) if available under one or
// more of these names:
//
// /usr/local/share/mime/globs2
// /usr/share/mime/globs2
// /etc/mime.types
// /etc/apache2/mime.types
// /etc/apache/mime.types
//
// On Windows, MIME types are extracted from the registry.
//
// Text types have the charset parameter set to "utf-8" by default.
func TypeByExtension(ext string) string {
once.Do(initMime)
// Case-sensitive lookup.
if v, ok := mimeTypes.Load(ext); ok {
return v.(string)
}
// Case-insensitive lookup.
// Optimistically assume a short ASCII extension and be
// allocation-free in that case.
var buf [10]byte
lower := buf[:0]
const utf8RuneSelf = 0x80 // from utf8 package, but not importing it.
for i := 0; i < len(ext); i++ {
c := ext[i]
if c >= utf8RuneSelf {
// Slow path.
si, _ := mimeTypesLower.Load(strings.ToLower(ext))
s, _ := si.(string)
return s
}
if 'A' <= c && c <= 'Z' {
lower = append(lower, c+('a'-'A'))
} else {
lower = append(lower, c)
}
}
si, _ := mimeTypesLower.Load(string(lower))
s, _ := si.(string)
return s
}
// ExtensionsByType returns the extensions known to be associated with the MIME
// type typ. The returned extensions will each begin with a leading dot, as in
// ".html". When typ has no associated extensions, ExtensionsByType returns an
// nil slice.
func ExtensionsByType(typ string) ([]string, error) {
justType, _, err := ParseMediaType(typ)
if err != nil {
return nil, err
}
once.Do(initMime)
s, ok := extensions.Load(justType)
if !ok {
return nil, nil
}
ret := append([]string(nil), s.([]string)...)
sort.Strings(ret)
return ret, nil
}
// AddExtensionType sets the MIME type associated with
// the extension ext to typ. The extension should begin with
// a leading dot, as in ".html".
func AddExtensionType(ext, typ string) error {
if !strings.HasPrefix(ext, ".") {
return fmt.Errorf("mime: extension %q missing leading dot", ext)
}
once.Do(initMime)
return setExtensionType(ext, typ)
}
func setExtensionType(extension, mimeType string) error {
justType, param, err := ParseMediaType(mimeType)
if err != nil {
return err
}
if strings.HasPrefix(mimeType, "text/") && param["charset"] == "" {
param["charset"] = "utf-8"
mimeType = FormatMediaType(mimeType, param)
}
extLower := strings.ToLower(extension)
mimeTypes.Store(extension, mimeType)
mimeTypesLower.Store(extLower, mimeType)
extensionsMu.Lock()
defer extensionsMu.Unlock()
var exts []string
if ei, ok := extensions.Load(justType); ok {
exts = ei.([]string)
}
for _, v := range exts {
if v == extLower {
return nil
}
}
extensions.Store(justType, append(exts, extLower))
return nil
}