mime: add support for Plan 9

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/10028043

src/pkg/mime/testdata/test.types.plan9

+# Copyright 2013 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.
+
+
+ # mime package test
+.t1		application	test		-		y # Simple test	
+.t2		text		test		-		y # Text test	

src/pkg/mime/type_plan9.go

+// Copyright 2013 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
+
+import (
+	"bufio"
+	"os"
+	"strings"
+)
+
+var typeFiles = []string{
+	"/sys/lib/mimetypes",
+}
+
+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) <= 2 || fields[0][0] != '.' {
+			continue
+		}
+		if fields[1] == "-" || fields[2] == "-" {
+			continue
+		}
+		setExtensionType(fields[0], fields[1]+"/"+fields[2])
+	}
+	if err := scanner.Err(); err != nil {
+		panic(err)
+	}
+}
+
+func initMime() {
+	for _, filename := range typeFiles {
+		loadMimeFile(filename)
+	}
+}
+
+func initMimeForTests() map[string]string {
+	typeFiles = []string{"testdata/test.types.plan9"}
+	return map[string]string{
+		".t1":  "application/test",
+		".t2":  "text/test; charset=utf-8",
+		".png": "image/png",
+	}
+}

src/pkg/mime/type_unix.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build darwin freebsd linux netbsd openbsd plan9
+// +build darwin freebsd linux netbsd openbsd
 
 package mime