// 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. package vcs import ( "encoding/xml" "fmt" "io" "strings" ) // 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 default: 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 section or the beginning of the . // // This copy of cmd/go/internal/vcs.parseMetaGoImports always operates // in IgnoreMod ModuleMode. 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.RawToken() if err != nil { if err == io.EOF || len(imports) > 0 { err = nil } return } if e, ok := t.(xml.StartElement); ok && strings.EqualFold(e.Name.Local, "body") { return } if e, ok := t.(xml.EndElement); ok && strings.EqualFold(e.Name.Local, "head") { return } e, ok := t.(xml.StartElement) if !ok || !strings.EqualFold(e.Name.Local, "meta") { continue } if attrValue(e.Attr, "name") != "go-import" { continue } if f := strings.Fields(attrValue(e.Attr, "content")); len(f) == 3 { // Ignore VCS type "mod", which is applicable only in module mode. if f[1] == "mod" { continue } 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 "" }