// Copyright 2012 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package vcs
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import (
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"encoding/xml"
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"fmt"
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"io"
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"strings"
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)
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// charsetReader returns a reader for the given charset. Currently
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// it only supports UTF-8 and ASCII. Otherwise, it returns a meaningful
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// error which is printed by go get, so the user can find why the package
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// wasn't downloaded if the encoding is not supported. Note that, in
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// order to reduce potential errors, ASCII is treated as UTF-8 (i.e. characters
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// greater than 0x7f are not rejected).
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func charsetReader(charset string, input io.Reader) (io.Reader, error) {
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switch strings.ToLower(charset) {
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case "ascii":
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return input, nil
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default:
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return nil, fmt.Errorf("can't decode XML document using charset %q", charset)
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}
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}
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// parseMetaGoImports returns meta imports from the HTML in r.
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// Parsing ends at the end of the <head> section or the beginning of the <body>.
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func parseMetaGoImports(r io.Reader) (imports []metaImport, err error) {
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d := xml.NewDecoder(r)
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d.CharsetReader = charsetReader
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d.Strict = false
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var t xml.Token
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for {
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t, err = d.Token()
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if err != nil {
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if err == io.EOF || len(imports) > 0 {
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err = nil
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}
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return
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}
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if e, ok := t.(xml.StartElement); ok && strings.EqualFold(e.Name.Local, "body") {
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return
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}
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if e, ok := t.(xml.EndElement); ok && strings.EqualFold(e.Name.Local, "head") {
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return
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}
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e, ok := t.(xml.StartElement)
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if !ok || !strings.EqualFold(e.Name.Local, "meta") {
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continue
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}
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if attrValue(e.Attr, "name") != "go-import" {
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continue
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}
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if f := strings.Fields(attrValue(e.Attr, "content")); len(f) == 3 {
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imports = append(imports, metaImport{
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Prefix: f[0],
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VCS: f[1],
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RepoRoot: f[2],
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})
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}
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}
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}
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// attrValue returns the attribute value for the case-insensitive key
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// `name', or the empty string if nothing is found.
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func attrValue(attrs []xml.Attr, name string) string {
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for _, a := range attrs {
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if strings.EqualFold(a.Name.Local, name) {
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return a.Value
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}
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}
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return ""
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}
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