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authorRuss Cox <rsc@golang.org>2014-09-08 00:08:51 -0400
committerRuss Cox <rsc@golang.org>2014-09-08 00:08:51 -0400
commit8528da672cc093d4dd06732819abc1f7b6b5a46e (patch)
tree334be80d4a4c85b77db6f6fdb67cbf0528cba5f5 /src/mime/type.go
parent73bcb69f272cbf34ddcc9daa56427a8683b5a95d (diff)
downloadgo-8528da672cc093d4dd06732819abc1f7b6b5a46e.tar.gz
build: move package sources from src/pkg to src
Preparation was in CL 134570043. This CL contains only the effect of 'hg mv src/pkg/* src'. For more about the move, see golang.org/s/go14nopkg.
Diffstat (limited to 'src/mime/type.go')
-rw-r--r--src/mime/type.go121
1 files changed, 121 insertions, 0 deletions
diff --git a/src/mime/type.go b/src/mime/type.go
new file mode 100644
index 000000000..ffda1f0ce
--- /dev/null
+++ b/src/mime/type.go
@@ -0,0 +1,121 @@
+// 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"
+ "strings"
+ "sync"
+)
+
+var (
+ mimeLock sync.RWMutex
+ mimeTypesLower = map[string]string{
+ ".css": "text/css; charset=utf-8",
+ ".gif": "image/gif",
+ ".htm": "text/html; charset=utf-8",
+ ".html": "text/html; charset=utf-8",
+ ".jpg": "image/jpeg",
+ ".js": "application/x-javascript",
+ ".pdf": "application/pdf",
+ ".png": "image/png",
+ ".xml": "text/xml; charset=utf-8",
+ }
+ mimeTypes = clone(mimeTypesLower)
+)
+
+func clone(m map[string]string) map[string]string {
+ m2 := make(map[string]string, len(m))
+ for k, v := range m {
+ m2[k] = v
+ if strings.ToLower(k) != k {
+ panic("keys in mimeTypesLower must be lowercase")
+ }
+ }
+ return m2
+}
+
+var once sync.Once // guards initMime
+
+// 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.types file(s) if available under one or more of these
+// names:
+//
+// /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)
+ mimeLock.RLock()
+ defer mimeLock.RUnlock()
+
+ // Case-sensitive lookup.
+ v := mimeTypes[ext]
+ if v != "" {
+ return v
+ }
+
+ // 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.
+ return mimeTypesLower[strings.ToLower(ext)]
+ }
+ if 'A' <= c && c <= 'Z' {
+ lower = append(lower, c+('a'-'A'))
+ } else {
+ lower = append(lower, c)
+ }
+ }
+ // The conversion from []byte to string doesn't allocate in
+ // a map lookup.
+ return mimeTypesLower[string(lower)]
+}
+
+// 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 misses dot`, ext)
+ }
+ once.Do(initMime)
+ return setExtensionType(ext, typ)
+}
+
+func setExtensionType(extension, mimeType string) error {
+ _, 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)
+
+ mimeLock.Lock()
+ mimeTypes[extension] = mimeType
+ mimeTypesLower[extLower] = mimeType
+ mimeLock.Unlock()
+ return nil
+}