func escFnsEq(a, b string) bool {
	if e := equivEscapers[a]; e != "" {
		a = e
	}
	if e := equivEscapers[b]; e != "" {
		b = e
	}
	return a == b
}
escFnsEq reports whether the two escaping functions are equivalent.
package template
import (
	"bytes"
	"fmt"
	"html"
	"io"
	"text/template"
	"text/template/parse"
)
func escapeTemplate(tmpl *Template, node parse.Node, name string) error {
	c, _ := tmpl.esc.escapeTree(context{}, node, name, 0)
	var err error
	if c.err != nil {
		err, c.err.Name = c.err, name
	} else if c.state != stateText {
		err = &Error{ErrEndContext, nil, name, 0, fmt.Sprintf("ends in a non-text context: %v", c)}
	}
	if err != nil {
		if t := tmpl.set[name]; t != nil {
			t.escapeErr = err
			t.text.Tree = nil
			t.Tree = nil
		}
		return err
	}
	tmpl.esc.commit()
	if t := tmpl.set[name]; t != nil {
		t.escapeErr = escapeOK
		t.Tree = t.text.Tree
	}
	return nil
}
func evalArgs(args ...interface{}) string {
	if len(args) == 1 {
		if s, ok := args[0].(string); ok {
			return s
		}
	}
	for i, arg := range args {
		args[i] = indirectToStringerOrError(arg)
	}
	return fmt.Sprint(args...)
}
var funcMap = template.FuncMap{
	"_html_template_attrescaper":     attrEscaper,
	"_html_template_commentescaper":  commentEscaper,
	"_html_template_cssescaper":      cssEscaper,
	"_html_template_cssvaluefilter":  cssValueFilter,
	"_html_template_htmlnamefilter":  htmlNameFilter,
	"_html_template_htmlescaper":     htmlEscaper,
	"_html_template_jsregexpescaper": jsRegexpEscaper,
	"_html_template_jsstrescaper":    jsStrEscaper,
	"_html_template_jsvalescaper":    jsValEscaper,
	"_html_template_nospaceescaper":  htmlNospaceEscaper,
	"_html_template_rcdataescaper":   rcdataEscaper,
	"_html_template_urlescaper":      urlEscaper,
	"_html_template_urlfilter":       urlFilter,
	"_html_template_urlnormalizer":   urlNormalizer,
	"_eval_args_":                    evalArgs,
}
type escaper struct {
	ns *nameSpace
	output map[string]context
	derived map[string]*template.Template
	called map[string]bool
	actionNodeEdits   map[*parse.ActionNode][]string
	templateNodeEdits map[*parse.TemplateNode]string
	textNodeEdits     map[*parse.TextNode][]byte
}
func makeEscaper(n *nameSpace) escaper {
	return escaper{
		n,
		map[string]context{},
		map[string]*template.Template{},
		map[string]bool{},
		map[*parse.ActionNode][]string{},
		map[*parse.TemplateNode]string{},
		map[*parse.TextNode][]byte{},
	}
}
const filterFailsafe = "ZgotmplZ"
func (e *escaper) escape(c context, n parse.Node) context {
	switch n := n.(type) {
	case *parse.ActionNode:
		return e.escapeAction(c, n)
	case *parse.IfNode:
		return e.escapeBranch(c, &n.BranchNode, "if")
	case *parse.ListNode:
		return e.escapeList(c, n)
	case *parse.RangeNode:
		return e.escapeBranch(c, &n.BranchNode, "range")
	case *parse.TemplateNode:
		return e.escapeTemplate(c, n)
	case *parse.TextNode:
		return e.escapeText(c, n)
	case *parse.WithNode:
		return e.escapeBranch(c, &n.BranchNode, "with")
	}
	panic("escaping " + n.String() + " is unimplemented")
}
func (e *escaper) escapeAction(c context, n *parse.ActionNode) context {
	if len(n.Pipe.Decl) != 0 {
		return c
	}
	c = nudge(c)
	for pos, idNode := range n.Pipe.Cmds {
		node, ok := idNode.Args[0].(*parse.IdentifierNode)
		if !ok {
			continue
		}
		ident := node.Ident
		if _, ok := predefinedEscapers[ident]; ok {
			if pos < len(n.Pipe.Cmds)-1 ||
				c.state == stateAttr && c.delim == delimSpaceOrTagEnd && ident == "html" {
				return context{
					state: stateError,
					err:   errorf(ErrPredefinedEscaper, n, n.Line, "predefined escaper %q disallowed in template", ident),
				}
			}
		}
	}
	s := make([]string, 0, 3)
	switch c.state {
	case stateError:
		return c
	case stateURL, stateCSSDqStr, stateCSSSqStr, stateCSSDqURL, stateCSSSqURL, stateCSSURL:
		switch c.urlPart {
		case urlPartNone:
			s = append(s, "_html_template_urlfilter")
			fallthrough
		case urlPartPreQuery:
			switch c.state {
			case stateCSSDqStr, stateCSSSqStr:
				s = append(s, "_html_template_cssescaper")
			default:
				s = append(s, "_html_template_urlnormalizer")
			}
		case urlPartQueryOrFrag:
			s = append(s, "_html_template_urlescaper")
		case urlPartUnknown:
			return context{
				state: stateError,
				err:   errorf(ErrAmbigContext, n, n.Line, "%s appears in an ambiguous context within a URL", n),
			}
		default:
			panic(c.urlPart.String())
		}
	case stateJS:
		s = append(s, "_html_template_jsvalescaper")
		c.jsCtx = jsCtxDivOp
	case stateJSDqStr, stateJSSqStr:
		s = append(s, "_html_template_jsstrescaper")
	case stateJSRegexp:
		s = append(s, "_html_template_jsregexpescaper")
	case stateCSS:
		s = append(s, "_html_template_cssvaluefilter")
	case stateText:
		s = append(s, "_html_template_htmlescaper")
	case stateRCDATA:
		s = append(s, "_html_template_rcdataescaper")
	case stateAttr:
	case stateAttrName, stateTag:
		c.state = stateAttrName
		s = append(s, "_html_template_htmlnamefilter")
	default:
		if isComment(c.state) {
			s = append(s, "_html_template_commentescaper")
		} else {
			panic("unexpected state " + c.state.String())
		}
	}
	switch c.delim {
	case delimNone:
	case delimSpaceOrTagEnd:
		s = append(s, "_html_template_nospaceescaper")
	default:
		s = append(s, "_html_template_attrescaper")
	}
	e.editActionNode(n, s)
	return c
}
func ensurePipelineContains(p *parse.PipeNode, s []string) {
	if len(s) == 0 {
		return
	}
	pipelineLen := len(p.Cmds)
	if pipelineLen > 0 {
		lastCmd := p.Cmds[pipelineLen-1]
		if idNode, ok := lastCmd.Args[0].(*parse.IdentifierNode); ok {
			if esc := idNode.Ident; predefinedEscapers[esc] {
				if len(p.Cmds) == 1 && len(lastCmd.Args) > 1 {
					lastCmd.Args[0] = parse.NewIdentifier("_eval_args_").SetTree(nil).SetPos(lastCmd.Args[0].Position())
					p.Cmds = appendCmd(p.Cmds, newIdentCmd(esc, p.Position()))
					pipelineLen++
				}
				dup := false
				for i, escaper := range s {
					if escFnsEq(esc, escaper) {
						s[i] = idNode.Ident
						dup = true
					}
				}
				if dup {
					pipelineLen--
				}
			}
		}
	}
	newCmds := make([]*parse.CommandNode, pipelineLen, pipelineLen+len(s))
	copy(newCmds, p.Cmds)
	for _, name := range s {
		newCmds = appendCmd(newCmds, newIdentCmd(name, p.Position()))
	}
	p.Cmds = newCmds
}
var predefinedEscapers = map[string]bool{
	"html":     true,
	"urlquery": true,
}
var equivEscapers = map[string]string{
	"_html_template_attrescaper":   "html",
	"_html_template_htmlescaper":   "html",
	"_html_template_rcdataescaper": "html",
	"_html_template_urlescaper": "urlquery",
	"_html_template_urlnormalizer": "urlquery",
}