1 files changed, 339 insertions, 0 deletions
diff --git a/src/html/template/context.go b/src/html/template/context.go
new file mode 100644
index 000000000..59e794d68
--- /dev/null
+++ b/src/html/template/context.go
@@ -0,0 +1,339 @@
+// Copyright 2011 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 template
+
+import (
+	"fmt"
+)
+
+// context describes the state an HTML parser must be in when it reaches the
+// portion of HTML produced by evaluating a particular template node.
+//
+// The zero value of type context is the start context for a template that
+// produces an HTML fragment as defined at
+// http://www.w3.org/TR/html5/syntax.html#the-end
+// where the context element is null.
+type context struct {
+	state   state
+	delim   delim
+	urlPart urlPart
+	jsCtx   jsCtx
+	attr    attr
+	element element
+	err     *Error
+}
+
+func (c context) String() string {
+	return fmt.Sprintf("{%v %v %v %v %v %v %v}", c.state, c.delim, c.urlPart, c.jsCtx, c.attr, c.element, c.err)
+}
+
+// eq reports whether two contexts are equal.
+func (c context) eq(d context) bool {
+	return c.state == d.state &&
+		c.delim == d.delim &&
+		c.urlPart == d.urlPart &&
+		c.jsCtx == d.jsCtx &&
+		c.attr == d.attr &&
+		c.element == d.element &&
+		c.err == d.err
+}
+
+// mangle produces an identifier that includes a suffix that distinguishes it
+// from template names mangled with different contexts.
+func (c context) mangle(templateName string) string {
+	// The mangled name for the default context is the input templateName.
+	if c.state == stateText {
+		return templateName
+	}
+	s := templateName + "$htmltemplate_" + c.state.String()
+	if c.delim != 0 {
+		s += "_" + c.delim.String()
+	}
+	if c.urlPart != 0 {
+		s += "_" + c.urlPart.String()
+	}
+	if c.jsCtx != 0 {
+		s += "_" + c.jsCtx.String()
+	}
+	if c.attr != 0 {
+		s += "_" + c.attr.String()
+	}
+	if c.element != 0 {
+		s += "_" + c.element.String()
+	}
+	return s
+}
+
+// state describes a high-level HTML parser state.
+//
+// It bounds the top of the element stack, and by extension the HTML insertion
+// mode, but also contains state that does not correspond to anything in the
+// HTML5 parsing algorithm because a single token production in the HTML
+// grammar may contain embedded actions in a template. For instance, the quoted
+// HTML attribute produced by
+//     <div title="Hello {{.World}}">
+// is a single token in HTML's grammar but in a template spans several nodes.
+type state uint8
+
+const (
+	// stateText is parsed character data. An HTML parser is in
+	// this state when its parse position is outside an HTML tag,
+	// directive, comment, and special element body.
+	stateText state = iota
+	// stateTag occurs before an HTML attribute or the end of a tag.
+	stateTag
+	// stateAttrName occurs inside an attribute name.
+	// It occurs between the ^'s in ` ^name^ = value`.
+	stateAttrName
+	// stateAfterName occurs after an attr name has ended but before any
+	// equals sign. It occurs between the ^'s in ` name^ ^= value`.
+	stateAfterName
+	// stateBeforeValue occurs after the equals sign but before the value.
+	// It occurs between the ^'s in ` name =^ ^value`.
+	stateBeforeValue
+	// stateHTMLCmt occurs inside an <!-- HTML comment -->.
+	stateHTMLCmt
+	// stateRCDATA occurs inside an RCDATA element (<textarea> or <title>)
+	// as described at http://www.w3.org/TR/html5/syntax.html#elements-0
+	stateRCDATA
+	// stateAttr occurs inside an HTML attribute whose content is text.
+	stateAttr
+	// stateURL occurs inside an HTML attribute whose content is a URL.
+	stateURL
+	// stateJS occurs inside an event handler or script element.
+	stateJS
+	// stateJSDqStr occurs inside a JavaScript double quoted string.
+	stateJSDqStr
+	// stateJSSqStr occurs inside a JavaScript single quoted string.
+	stateJSSqStr
+	// stateJSRegexp occurs inside a JavaScript regexp literal.
+	stateJSRegexp
+	// stateJSBlockCmt occurs inside a JavaScript /* block comment */.
+	stateJSBlockCmt
+	// stateJSLineCmt occurs inside a JavaScript // line comment.
+	stateJSLineCmt
+	// stateCSS occurs inside a <style> element or style attribute.
+	stateCSS
+	// stateCSSDqStr occurs inside a CSS double quoted string.
+	stateCSSDqStr
+	// stateCSSSqStr occurs inside a CSS single quoted string.
+	stateCSSSqStr
+	// stateCSSDqURL occurs inside a CSS double quoted url("...").
+	stateCSSDqURL
+	// stateCSSSqURL occurs inside a CSS single quoted url('...').
+	stateCSSSqURL
+	// stateCSSURL occurs inside a CSS unquoted url(...).
+	stateCSSURL
+	// stateCSSBlockCmt occurs inside a CSS /* block comment */.
+	stateCSSBlockCmt
+	// stateCSSLineCmt occurs inside a CSS // line comment.
+	stateCSSLineCmt
+	// stateError is an infectious error state outside any valid
+	// HTML/CSS/JS construct.
+	stateError
+)
+
+var stateNames = [...]string{
+	stateText:        "stateText",
+	stateTag:         "stateTag",
+	stateAttrName:    "stateAttrName",
+	stateAfterName:   "stateAfterName",
+	stateBeforeValue: "stateBeforeValue",
+	stateHTMLCmt:     "stateHTMLCmt",
+	stateRCDATA:      "stateRCDATA",
+	stateAttr:        "stateAttr",
+	stateURL:         "stateURL",
+	stateJS:          "stateJS",
+	stateJSDqStr:     "stateJSDqStr",
+	stateJSSqStr:     "stateJSSqStr",
+	stateJSRegexp:    "stateJSRegexp",
+	stateJSBlockCmt:  "stateJSBlockCmt",
+	stateJSLineCmt:   "stateJSLineCmt",
+	stateCSS:         "stateCSS",
+	stateCSSDqStr:    "stateCSSDqStr",
+	stateCSSSqStr:    "stateCSSSqStr",
+	stateCSSDqURL:    "stateCSSDqURL",
+	stateCSSSqURL:    "stateCSSSqURL",
+	stateCSSURL:      "stateCSSURL",
+	stateCSSBlockCmt: "stateCSSBlockCmt",
+	stateCSSLineCmt:  "stateCSSLineCmt",
+	stateError:       "stateError",
+}
+
+func (s state) String() string {
+	if int(s) < len(stateNames) {
+		return stateNames[s]
+	}
+	return fmt.Sprintf("illegal state %d", int(s))
+}
+
+// isComment is true for any state that contains content meant for template
+// authors & maintainers, not for end-users or machines.
+func isComment(s state) bool {
+	switch s {
+	case stateHTMLCmt, stateJSBlockCmt, stateJSLineCmt, stateCSSBlockCmt, stateCSSLineCmt:
+		return true
+	}
+	return false
+}
+
+// isInTag return whether s occurs solely inside an HTML tag.
+func isInTag(s state) bool {
+	switch s {
+	case stateTag, stateAttrName, stateAfterName, stateBeforeValue, stateAttr:
+		return true
+	}
+	return false
+}
+
+// delim is the delimiter that will end the current HTML attribute.
+type delim uint8
+
+const (
+	// delimNone occurs outside any attribute.
+	delimNone delim = iota
+	// delimDoubleQuote occurs when a double quote (") closes the attribute.
+	delimDoubleQuote
+	// delimSingleQuote occurs when a single quote (') closes the attribute.
+	delimSingleQuote
+	// delimSpaceOrTagEnd occurs when a space or right angle bracket (>)
+	// closes the attribute.
+	delimSpaceOrTagEnd
+)
+
+var delimNames = [...]string{
+	delimNone:          "delimNone",
+	delimDoubleQuote:   "delimDoubleQuote",
+	delimSingleQuote:   "delimSingleQuote",
+	delimSpaceOrTagEnd: "delimSpaceOrTagEnd",
+}
+
+func (d delim) String() string {
+	if int(d) < len(delimNames) {
+		return delimNames[d]
+	}
+	return fmt.Sprintf("illegal delim %d", int(d))
+}
+
+// urlPart identifies a part in an RFC 3986 hierarchical URL to allow different
+// encoding strategies.
+type urlPart uint8
+
+const (
+	// urlPartNone occurs when not in a URL, or possibly at the start:
+	// ^ in "^http://auth/path?k=v#frag".
+	urlPartNone urlPart = iota
+	// urlPartPreQuery occurs in the scheme, authority, or path; between the
+	// ^s in "h^ttp://auth/path^?k=v#frag".
+	urlPartPreQuery
+	// urlPartQueryOrFrag occurs in the query portion between the ^s in
+	// "http://auth/path?^k=v#frag^".
+	urlPartQueryOrFrag
+	// urlPartUnknown occurs due to joining of contexts both before and
+	// after the query separator.
+	urlPartUnknown
+)
+
+var urlPartNames = [...]string{
+	urlPartNone:        "urlPartNone",
+	urlPartPreQuery:    "urlPartPreQuery",
+	urlPartQueryOrFrag: "urlPartQueryOrFrag",
+	urlPartUnknown:     "urlPartUnknown",
+}
+
+func (u urlPart) String() string {
+	if int(u) < len(urlPartNames) {
+		return urlPartNames[u]
+	}
+	return fmt.Sprintf("illegal urlPart %d", int(u))
+}
+
+// jsCtx determines whether a '/' starts a regular expression literal or a
+// division operator.
+type jsCtx uint8
+
+const (
+	// jsCtxRegexp occurs where a '/' would start a regexp literal.
+	jsCtxRegexp jsCtx = iota
+	// jsCtxDivOp occurs where a '/' would start a division operator.
+	jsCtxDivOp
+	// jsCtxUnknown occurs where a '/' is ambiguous due to context joining.
+	jsCtxUnknown
+)
+
+func (c jsCtx) String() string {
+	switch c {
+	case jsCtxRegexp:
+		return "jsCtxRegexp"
+	case jsCtxDivOp:
+		return "jsCtxDivOp"
+	case jsCtxUnknown:
+		return "jsCtxUnknown"
+	}
+	return fmt.Sprintf("illegal jsCtx %d", int(c))
+}
+
+// element identifies the HTML element when inside a start tag or special body.
+// Certain HTML element (for example <script> and <style>) have bodies that are
+// treated differently from stateText so the element type is necessary to
+// transition into the correct context at the end of a tag and to identify the
+// end delimiter for the body.
+type element uint8
+
+const (
+	// elementNone occurs outside a special tag or special element body.
+	elementNone element = iota
+	// elementScript corresponds to the raw text <script> element.
+	elementScript
+	// elementStyle corresponds to the raw text <style> element.
+	elementStyle
+	// elementTextarea corresponds to the RCDATA <textarea> element.
+	elementTextarea
+	// elementTitle corresponds to the RCDATA <title> element.
+	elementTitle
+)
+
+var elementNames = [...]string{
+	elementNone:     "elementNone",
+	elementScript:   "elementScript",
+	elementStyle:    "elementStyle",
+	elementTextarea: "elementTextarea",
+	elementTitle:    "elementTitle",
+}
+
+func (e element) String() string {
+	if int(e) < len(elementNames) {
+		return elementNames[e]
+	}
+	return fmt.Sprintf("illegal element %d", int(e))
+}
+
+// attr identifies the most recent HTML attribute when inside a start tag.
+type attr uint8
+
+const (
+	// attrNone corresponds to a normal attribute or no attribute.
+	attrNone attr = iota
+	// attrScript corresponds to an event handler attribute.
+	attrScript
+	// attrStyle corresponds to the style attribute whose value is CSS.
+	attrStyle
+	// attrURL corresponds to an attribute whose value is a URL.
+	attrURL
+)
+
+var attrNames = [...]string{
+	attrNone:   "attrNone",
+	attrScript: "attrScript",
+	attrStyle:  "attrStyle",
+	attrURL:    "attrURL",
+}
+
+func (a attr) String() string {
+	if int(a) < len(attrNames) {
+		return attrNames[a]
+	}
+	return fmt.Sprintf("illegal attr %d", int(a))
+}