// Performs the actual sanitization process.
func (p *Policy) sanitize(r io.Reader) *bytes.Buffer {
// It is possible that the developer has created the policy via:
// p := bluemonday.Policy{}
// rather than:
// p := bluemonday.NewPolicy()
// If this is the case, and if they haven't yet triggered an action that
// would initiliaze the maps, then we need to do that.
p.init()
var buff bytes.Buffer
tokenizer := html.NewTokenizer(r)
skipElementContent := false
skipClosingTag := false
for {
if tokenizer.Next() == html.ErrorToken {
err := tokenizer.Err()
if err == io.EOF {
// End of input means end of processing
return &buff
}
// Raw tokenizer error
return &bytes.Buffer{}
}
token := tokenizer.Token()
switch token.Type {
case html.DoctypeToken:
if p.allowDocType {
buff.WriteString(token.String())
}
case html.CommentToken:
// Comments are ignored by default
case html.StartTagToken:
aps, ok := p.elsAndAttrs[token.Data]
if !ok {
if _, ok := p.setOfElementsToSkipContent[token.Data]; ok {
skipElementContent = true
}
break
}
if len(token.Attr) != 0 {
token.Attr = p.sanitizeAttrs(token.Data, token.Attr, aps)
}
if len(token.Attr) == 0 {
if !p.allowNoAttrs(token.Data) {
skipClosingTag = true
break
}
}
buff.WriteString(token.String())
case html.EndTagToken:
if skipClosingTag {
skipClosingTag = false
break
}
if _, ok := p.elsAndAttrs[token.Data]; !ok {
if _, ok := p.setOfElementsToSkipContent[token.Data]; ok {
skipElementContent = false
}
break
}
buff.WriteString(token.String())
case html.SelfClosingTagToken:
aps, ok := p.elsAndAttrs[token.Data]
if !ok {
break
}
if len(token.Attr) != 0 {
token.Attr = p.sanitizeAttrs(token.Data, token.Attr, aps)
}
if len(token.Attr) == 0 && !p.allowNoAttrs(token.Data) {
break
}
buff.WriteString(token.String())
case html.TextToken:
if !skipElementContent {
buff.WriteString(token.String())
}
default:
// A token that didn't exist in the html package when we wrote this
return &bytes.Buffer{}
}
}
}
func prescan(content []byte) (e encoding.Encoding, name string) {
z := html.NewTokenizer(bytes.NewReader(content))
for {
switch z.Next() {
case html.ErrorToken:
return nil, ""
case html.StartTagToken, html.SelfClosingTagToken:
tagName, hasAttr := z.TagName()
if !bytes.Equal(tagName, []byte("meta")) {
continue
}
attrList := make(map[string]bool)
gotPragma := false
const (
dontKnow = iota
doNeedPragma
doNotNeedPragma
)
needPragma := dontKnow
name = ""
e = nil
for hasAttr {
var key, val []byte
key, val, hasAttr = z.TagAttr()
ks := string(key)
if attrList[ks] {
continue
}
attrList[ks] = true
for i, c := range val {
if 'A' <= c && c <= 'Z' {
val[i] = c + 0x20
}
}
switch ks {
case "http-equiv":
if bytes.Equal(val, []byte("content-type")) {
gotPragma = true
}
case "content":
if e == nil {
name = fromMetaElement(string(val))
if name != "" {
e, name = Lookup(name)
if e != nil {
needPragma = doNeedPragma
}
}
}
case "charset":
e, name = Lookup(string(val))
needPragma = doNotNeedPragma
}
}
if needPragma == dontKnow || needPragma == doNeedPragma && !gotPragma {
continue
}
if strings.HasPrefix(name, "utf-16") {
name = "utf-8"
e = encoding.Nop
}
if e != nil {
return e, name
}
}
}
}