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// 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.
//go:build unix || (js && wasm)
package mime
import (
"bufio"
"os"
"strings"
)
func init() {
osInitMime = initMimeUnix
}
// See https://specifications.freedesktop.org/shared-mime-info-spec/shared-mime-info-spec-0.21.html
// for the FreeDesktop Shared MIME-info Database specification.
var mimeGlobs = []string{
"/usr/local/share/mime/globs2",
"/usr/share/mime/globs2",
}
// Common locations for mime.types files on unix.
var typeFiles = []string{
"/etc/mime.types",
"/etc/apache2/mime.types",
"/etc/apache/mime.types",
"/etc/httpd/conf/mime.types",
}
func loadMimeGlobsFile(filename string) error {
f, err := os.Open(filename)
if err != nil {
return err
}
defer f.Close()
scanner := bufio.NewScanner(f)
for scanner.Scan() {
// Each line should be of format: weight:mimetype:glob[:morefields...]
fields := strings.Split(scanner.Text(), ":")
if len(fields) < 3 || len(fields[0]) < 1 || len(fields[2]) < 3 {
continue
} else if fields[0][0] == '#' || fields[2][0] != '*' || fields[2][1] != '.' {
continue
}
extension := fields[2][1:]
if strings.ContainsAny(extension, "?*[") {
// Not a bare extension, but a glob. Ignore for now:
// - we do not have an implementation for this glob
// syntax (translation to path/filepath.Match could
// be possible)
// - support for globs with weight ordering would have
// performance impact to all lookups to support the
// rarely seen glob entries
// - trying to match glob metacharacters literally is
// not useful
continue
}
if _, ok := mimeTypes.Load(extension); ok {
// We've already seen this extension.
// The file is in weight order, so we keep
// the first entry that we see.
continue
}
setExtensionType(extension, fields[1])
}
if err := scanner.Err(); err != nil {
panic(err)
}
return nil
}
func loadMimeFile(filename string) {
f, err := os.Open(filename)
if err != nil {
return
}
defer f.Close()
scanner := bufio.NewScanner(f)
for scanner.Scan() {
fields := strings.Fields(scanner.Text())
if len(fields) <= 1 || fields[0][0] == '#' {
continue
}
mimeType := fields[0]
for _, ext := range fields[1:] {
if ext[0] == '#' {
break
}
setExtensionType("."+ext, mimeType)
}
}
if err := scanner.Err(); err != nil {
panic(err)
}
}
func initMimeUnix() {
for _, filename := range mimeGlobs {
if err := loadMimeGlobsFile(filename); err == nil {
return // Stop checking more files if mimetype database is found.
}
}
// Fallback if no system-generated mimetype database exists.
for _, filename := range typeFiles {
loadMimeFile(filename)
}
}
func initMimeForTests() map[string]string {
mimeGlobs = []string{""}
typeFiles = []string{"testdata/test.types"}
return map[string]string{
".T1": "application/test",
".t2": "text/test; charset=utf-8",
".png": "image/png",
}
}