blob: b9f42799546e306f8f3762d00d2c6d273d3e50a2 [file] [log] [blame]
// Copyright 2012 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.
// +build !cmd_go_bootstrap
// This code is compiled into the real 'go' binary, but it is not
// compiled into the binary that is built during all.bash, so as
// to avoid needing to build net (and thus use cgo) during the
// bootstrap process.
package main
import (
// charsetReader returns a reader for the given charset. Currently
// it only supports UTF-8 and ASCII. Otherwise, it returns a meaningful
// error which is printed by go get, so the user can find why the package
// wasn't downloaded if the encoding is not supported. Note that, in
// order to reduce potential errors, ASCII is treated as UTF-8 (i.e. characters
// greater than 0x7f are not rejected).
func charsetReader(charset string, input io.Reader) (io.Reader, error) {
switch strings.ToLower(charset) {
case "ascii":
return input, nil
return nil, fmt.Errorf("can't decode XML document using charset %q", charset)
// parseMetaGoImports returns meta imports from the HTML in r.
// Parsing ends at the end of the <head> section or the beginning of the <body>.
func parseMetaGoImports(r io.Reader) (imports []metaImport, err error) {
d := xml.NewDecoder(r)
d.CharsetReader = charsetReader
d.Strict = false
var t xml.Token
for {
t, err = d.Token()
if err != nil {
if err == io.EOF {
err = nil
if e, ok := t.(xml.StartElement); ok && strings.EqualFold(e.Name.Local, "body") {
if e, ok := t.(xml.EndElement); ok && strings.EqualFold(e.Name.Local, "head") {
e, ok := t.(xml.StartElement)
if !ok || !strings.EqualFold(e.Name.Local, "meta") {
if attrValue(e.Attr, "name") != "go-import" {
if f := strings.Fields(attrValue(e.Attr, "content")); len(f) == 3 {
imports = append(imports, metaImport{
Prefix: f[0],
VCS: f[1],
RepoRoot: f[2],
// attrValue returns the attribute value for the case-insensitive key
// `name', or the empty string if nothing is found.
func attrValue(attrs []xml.Attr, name string) string {
for _, a := range attrs {
if strings.EqualFold(a.Name.Local, name) {
return a.Value
return ""