From 90feb03edc6a4c737e69f245a5b19a9e13c77570 Mon Sep 17 00:00:00 2001 From: Jordan Date: Thu, 10 Feb 2022 19:08:25 -0700 Subject: go mod vendor --- vendor/golang.org/x/net/html/parse.go | 2438 +++++++++++++++++++++++++++++++++ 1 file changed, 2438 insertions(+) create mode 100644 vendor/golang.org/x/net/html/parse.go (limited to 'vendor/golang.org/x/net/html/parse.go') diff --git a/vendor/golang.org/x/net/html/parse.go b/vendor/golang.org/x/net/html/parse.go new file mode 100644 index 0000000..f91466f --- /dev/null +++ b/vendor/golang.org/x/net/html/parse.go @@ -0,0 +1,2438 @@ +// Copyright 2010 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 html + +import ( + "errors" + "fmt" + "io" + "strings" + + a "golang.org/x/net/html/atom" +) + +// A parser implements the HTML5 parsing algorithm: +// https://html.spec.whatwg.org/multipage/syntax.html#tree-construction +type parser struct { + // tokenizer provides the tokens for the parser. + tokenizer *Tokenizer + // tok is the most recently read token. + tok Token + // Self-closing tags like
are treated as start tags, except that + // hasSelfClosingToken is set while they are being processed. + hasSelfClosingToken bool + // doc is the document root element. + doc *Node + // The stack of open elements (section 12.2.4.2) and active formatting + // elements (section 12.2.4.3). + oe, afe nodeStack + // Element pointers (section 12.2.4.4). + head, form *Node + // Other parsing state flags (section 12.2.4.5). + scripting, framesetOK bool + // The stack of template insertion modes + templateStack insertionModeStack + // im is the current insertion mode. + im insertionMode + // originalIM is the insertion mode to go back to after completing a text + // or inTableText insertion mode. + originalIM insertionMode + // fosterParenting is whether new elements should be inserted according to + // the foster parenting rules (section 12.2.6.1). + fosterParenting bool + // quirks is whether the parser is operating in "quirks mode." + quirks bool + // fragment is whether the parser is parsing an HTML fragment. + fragment bool + // context is the context element when parsing an HTML fragment + // (section 12.4). + context *Node +} + +func (p *parser) top() *Node { + if n := p.oe.top(); n != nil { + return n + } + return p.doc +} + +// Stop tags for use in popUntil. These come from section 12.2.4.2. +var ( + defaultScopeStopTags = map[string][]a.Atom{ + "": {a.Applet, a.Caption, a.Html, a.Table, a.Td, a.Th, a.Marquee, a.Object, a.Template}, + "math": {a.AnnotationXml, a.Mi, a.Mn, a.Mo, a.Ms, a.Mtext}, + "svg": {a.Desc, a.ForeignObject, a.Title}, + } +) + +type scope int + +const ( + defaultScope scope = iota + listItemScope + buttonScope + tableScope + tableRowScope + tableBodyScope + selectScope +) + +// popUntil pops the stack of open elements at the highest element whose tag +// is in matchTags, provided there is no higher element in the scope's stop +// tags (as defined in section 12.2.4.2). It returns whether or not there was +// such an element. If there was not, popUntil leaves the stack unchanged. +// +// For example, the set of stop tags for table scope is: "html", "table". If +// the stack was: +// ["html", "body", "font", "table", "b", "i", "u"] +// then popUntil(tableScope, "font") would return false, but +// popUntil(tableScope, "i") would return true and the stack would become: +// ["html", "body", "font", "table", "b"] +// +// If an element's tag is in both the stop tags and matchTags, then the stack +// will be popped and the function returns true (provided, of course, there was +// no higher element in the stack that was also in the stop tags). For example, +// popUntil(tableScope, "table") returns true and leaves: +// ["html", "body", "font"] +func (p *parser) popUntil(s scope, matchTags ...a.Atom) bool { + if i := p.indexOfElementInScope(s, matchTags...); i != -1 { + p.oe = p.oe[:i] + return true + } + return false +} + +// indexOfElementInScope returns the index in p.oe of the highest element whose +// tag is in matchTags that is in scope. If no matching element is in scope, it +// returns -1. +func (p *parser) indexOfElementInScope(s scope, matchTags ...a.Atom) int { + for i := len(p.oe) - 1; i >= 0; i-- { + tagAtom := p.oe[i].DataAtom + if p.oe[i].Namespace == "" { + for _, t := range matchTags { + if t == tagAtom { + return i + } + } + switch s { + case defaultScope: + // No-op. + case listItemScope: + if tagAtom == a.Ol || tagAtom == a.Ul { + return -1 + } + case buttonScope: + if tagAtom == a.Button { + return -1 + } + case tableScope: + if tagAtom == a.Html || tagAtom == a.Table || tagAtom == a.Template { + return -1 + } + case selectScope: + if tagAtom != a.Optgroup && tagAtom != a.Option { + return -1 + } + default: + panic("unreachable") + } + } + switch s { + case defaultScope, listItemScope, buttonScope: + for _, t := range defaultScopeStopTags[p.oe[i].Namespace] { + if t == tagAtom { + return -1 + } + } + } + } + return -1 +} + +// elementInScope is like popUntil, except that it doesn't modify the stack of +// open elements. +func (p *parser) elementInScope(s scope, matchTags ...a.Atom) bool { + return p.indexOfElementInScope(s, matchTags...) != -1 +} + +// clearStackToContext pops elements off the stack of open elements until a +// scope-defined element is found. +func (p *parser) clearStackToContext(s scope) { + for i := len(p.oe) - 1; i >= 0; i-- { + tagAtom := p.oe[i].DataAtom + switch s { + case tableScope: + if tagAtom == a.Html || tagAtom == a.Table || tagAtom == a.Template { + p.oe = p.oe[:i+1] + return + } + case tableRowScope: + if tagAtom == a.Html || tagAtom == a.Tr || tagAtom == a.Template { + p.oe = p.oe[:i+1] + return + } + case tableBodyScope: + if tagAtom == a.Html || tagAtom == a.Tbody || tagAtom == a.Tfoot || tagAtom == a.Thead || tagAtom == a.Template { + p.oe = p.oe[:i+1] + return + } + default: + panic("unreachable") + } + } +} + +// parseGenericRawTextElements implements the generic raw text element parsing +// algorithm defined in 12.2.6.2. +// https://html.spec.whatwg.org/multipage/parsing.html#parsing-elements-that-contain-only-text +// TODO: Since both RAWTEXT and RCDATA states are treated as tokenizer's part +// officially, need to make tokenizer consider both states. +func (p *parser) parseGenericRawTextElement() { + p.addElement() + p.originalIM = p.im + p.im = textIM +} + +// generateImpliedEndTags pops nodes off the stack of open elements as long as +// the top node has a tag name of dd, dt, li, optgroup, option, p, rb, rp, rt or rtc. +// If exceptions are specified, nodes with that name will not be popped off. +func (p *parser) generateImpliedEndTags(exceptions ...string) { + var i int +loop: + for i = len(p.oe) - 1; i >= 0; i-- { + n := p.oe[i] + if n.Type != ElementNode { + break + } + switch n.DataAtom { + case a.Dd, a.Dt, a.Li, a.Optgroup, a.Option, a.P, a.Rb, a.Rp, a.Rt, a.Rtc: + for _, except := range exceptions { + if n.Data == except { + break loop + } + } + continue + } + break + } + + p.oe = p.oe[:i+1] +} + +// addChild adds a child node n to the top element, and pushes n onto the stack +// of open elements if it is an element node. +func (p *parser) addChild(n *Node) { + if p.shouldFosterParent() { + p.fosterParent(n) + } else { + p.top().AppendChild(n) + } + + if n.Type == ElementNode { + p.oe = append(p.oe, n) + } +} + +// shouldFosterParent returns whether the next node to be added should be +// foster parented. +func (p *parser) shouldFosterParent() bool { + if p.fosterParenting { + switch p.top().DataAtom { + case a.Table, a.Tbody, a.Tfoot, a.Thead, a.Tr: + return true + } + } + return false +} + +// fosterParent adds a child node according to the foster parenting rules. +// Section 12.2.6.1, "foster parenting". +func (p *parser) fosterParent(n *Node) { + var table, parent, prev, template *Node + var i int + for i = len(p.oe) - 1; i >= 0; i-- { + if p.oe[i].DataAtom == a.Table { + table = p.oe[i] + break + } + } + + var j int + for j = len(p.oe) - 1; j >= 0; j-- { + if p.oe[j].DataAtom == a.Template { + template = p.oe[j] + break + } + } + + if template != nil && (table == nil || j > i) { + template.AppendChild(n) + return + } + + if table == nil { + // The foster parent is the html element. + parent = p.oe[0] + } else { + parent = table.Parent + } + if parent == nil { + parent = p.oe[i-1] + } + + if table != nil { + prev = table.PrevSibling + } else { + prev = parent.LastChild + } + if prev != nil && prev.Type == TextNode && n.Type == TextNode { + prev.Data += n.Data + return + } + + parent.InsertBefore(n, table) +} + +// addText adds text to the preceding node if it is a text node, or else it +// calls addChild with a new text node. +func (p *parser) addText(text string) { + if text == "" { + return + } + + if p.shouldFosterParent() { + p.fosterParent(&Node{ + Type: TextNode, + Data: text, + }) + return + } + + t := p.top() + if n := t.LastChild; n != nil && n.Type == TextNode { + n.Data += text + return + } + p.addChild(&Node{ + Type: TextNode, + Data: text, + }) +} + +// addElement adds a child element based on the current token. +func (p *parser) addElement() { + p.addChild(&Node{ + Type: ElementNode, + DataAtom: p.tok.DataAtom, + Data: p.tok.Data, + Attr: p.tok.Attr, + }) +} + +// Section 12.2.4.3. +func (p *parser) addFormattingElement() { + tagAtom, attr := p.tok.DataAtom, p.tok.Attr + p.addElement() + + // Implement the Noah's Ark clause, but with three per family instead of two. + identicalElements := 0 +findIdenticalElements: + for i := len(p.afe) - 1; i >= 0; i-- { + n := p.afe[i] + if n.Type == scopeMarkerNode { + break + } + if n.Type != ElementNode { + continue + } + if n.Namespace != "" { + continue + } + if n.DataAtom != tagAtom { + continue + } + if len(n.Attr) != len(attr) { + continue + } + compareAttributes: + for _, t0 := range n.Attr { + for _, t1 := range attr { + if t0.Key == t1.Key && t0.Namespace == t1.Namespace && t0.Val == t1.Val { + // Found a match for this attribute, continue with the next attribute. + continue compareAttributes + } + } + // If we get here, there is no attribute that matches a. + // Therefore the element is not identical to the new one. + continue findIdenticalElements + } + + identicalElements++ + if identicalElements >= 3 { + p.afe.remove(n) + } + } + + p.afe = append(p.afe, p.top()) +} + +// Section 12.2.4.3. +func (p *parser) clearActiveFormattingElements() { + for { + if n := p.afe.pop(); len(p.afe) == 0 || n.Type == scopeMarkerNode { + return + } + } +} + +// Section 12.2.4.3. +func (p *parser) reconstructActiveFormattingElements() { + n := p.afe.top() + if n == nil { + return + } + if n.Type == scopeMarkerNode || p.oe.index(n) != -1 { + return + } + i := len(p.afe) - 1 + for n.Type != scopeMarkerNode && p.oe.index(n) == -1 { + if i == 0 { + i = -1 + break + } + i-- + n = p.afe[i] + } + for { + i++ + clone := p.afe[i].clone() + p.addChild(clone) + p.afe[i] = clone + if i == len(p.afe)-1 { + break + } + } +} + +// Section 12.2.5. +func (p *parser) acknowledgeSelfClosingTag() { + p.hasSelfClosingToken = false +} + +// An insertion mode (section 12.2.4.1) is the state transition function from +// a particular state in the HTML5 parser's state machine. It updates the +// parser's fields depending on parser.tok (where ErrorToken means EOF). +// It returns whether the token was consumed. +type insertionMode func(*parser) bool + +// setOriginalIM sets the insertion mode to return to after completing a text or +// inTableText insertion mode. +// Section 12.2.4.1, "using the rules for". +func (p *parser) setOriginalIM() { + if p.originalIM != nil { + panic("html: bad parser state: originalIM was set twice") + } + p.originalIM = p.im +} + +// Section 12.2.4.1, "reset the insertion mode". +func (p *parser) resetInsertionMode() { + for i := len(p.oe) - 1; i >= 0; i-- { + n := p.oe[i] + last := i == 0 + if last && p.context != nil { + n = p.context + } + + switch n.DataAtom { + case a.Select: + if !last { + for ancestor, first := n, p.oe[0]; ancestor != first; { + ancestor = p.oe[p.oe.index(ancestor)-1] + switch ancestor.DataAtom { + case a.Template: + p.im = inSelectIM + return + case a.Table: + p.im = inSelectInTableIM + return + } + } + } + p.im = inSelectIM + case a.Td, a.Th: + // TODO: remove this divergence from the HTML5 spec. + // + // See https://bugs.chromium.org/p/chromium/issues/detail?id=829668 + p.im = inCellIM + case a.Tr: + p.im = inRowIM + case a.Tbody, a.Thead, a.Tfoot: + p.im = inTableBodyIM + case a.Caption: + p.im = inCaptionIM + case a.Colgroup: + p.im = inColumnGroupIM + case a.Table: + p.im = inTableIM + case a.Template: + // TODO: remove this divergence from the HTML5 spec. + if n.Namespace != "" { + continue + } + p.im = p.templateStack.top() + case a.Head: + // TODO: remove this divergence from the HTML5 spec. + // + // See https://bugs.chromium.org/p/chromium/issues/detail?id=829668 + p.im = inHeadIM + case a.Body: + p.im = inBodyIM + case a.Frameset: + p.im = inFramesetIM + case a.Html: + if p.head == nil { + p.im = beforeHeadIM + } else { + p.im = afterHeadIM + } + default: + if last { + p.im = inBodyIM + return + } + continue + } + return + } +} + +const whitespace = " \t\r\n\f" + +// Section 12.2.6.4.1. +func initialIM(p *parser) bool { + switch p.tok.Type { + case TextToken: + p.tok.Data = strings.TrimLeft(p.tok.Data, whitespace) + if len(p.tok.Data) == 0 { + // It was all whitespace, so ignore it. + return true + } + case CommentToken: + p.doc.AppendChild(&Node{ + Type: CommentNode, + Data: p.tok.Data, + }) + return true + case DoctypeToken: + n, quirks := parseDoctype(p.tok.Data) + p.doc.AppendChild(n) + p.quirks = quirks + p.im = beforeHTMLIM + return true + } + p.quirks = true + p.im = beforeHTMLIM + return false +} + +// Section 12.2.6.4.2. +func beforeHTMLIM(p *parser) bool { + switch p.tok.Type { + case DoctypeToken: + // Ignore the token. + return true + case TextToken: + p.tok.Data = strings.TrimLeft(p.tok.Data, whitespace) + if len(p.tok.Data) == 0 { + // It was all whitespace, so ignore it. + return true + } + case StartTagToken: + if p.tok.DataAtom == a.Html { + p.addElement() + p.im = beforeHeadIM + return true + } + case EndTagToken: + switch p.tok.DataAtom { + case a.Head, a.Body, a.Html, a.Br: + p.parseImpliedToken(StartTagToken, a.Html, a.Html.String()) + return false + default: + // Ignore the token. + return true + } + case CommentToken: + p.doc.AppendChild(&Node{ + Type: CommentNode, + Data: p.tok.Data, + }) + return true + } + p.parseImpliedToken(StartTagToken, a.Html, a.Html.String()) + return false +} + +// Section 12.2.6.4.3. +func beforeHeadIM(p *parser) bool { + switch p.tok.Type { + case TextToken: + p.tok.Data = strings.TrimLeft(p.tok.Data, whitespace) + if len(p.tok.Data) == 0 { + // It was all whitespace, so ignore it. + return true + } + case StartTagToken: + switch p.tok.DataAtom { + case a.Head: + p.addElement() + p.head = p.top() + p.im = inHeadIM + return true + case a.Html: + return inBodyIM(p) + } + case EndTagToken: + switch p.tok.DataAtom { + case a.Head, a.Body, a.Html, a.Br: + p.parseImpliedToken(StartTagToken, a.Head, a.Head.String()) + return false + default: + // Ignore the token. + return true + } + case CommentToken: + p.addChild(&Node{ + Type: CommentNode, + Data: p.tok.Data, + }) + return true + case DoctypeToken: + // Ignore the token. + return true + } + + p.parseImpliedToken(StartTagToken, a.Head, a.Head.String()) + return false +} + +// Section 12.2.6.4.4. +func inHeadIM(p *parser) bool { + switch p.tok.Type { + case TextToken: + s := strings.TrimLeft(p.tok.Data, whitespace) + if len(s) < len(p.tok.Data) { + // Add the initial whitespace to the current node. + p.addText(p.tok.Data[:len(p.tok.Data)-len(s)]) + if s == "" { + return true + } + p.tok.Data = s + } + case StartTagToken: + switch p.tok.DataAtom { + case a.Html: + return inBodyIM(p) + case a.Base, a.Basefont, a.Bgsound, a.Link, a.Meta: + p.addElement() + p.oe.pop() + p.acknowledgeSelfClosingTag() + return true + case a.Noscript: + if p.scripting { + p.parseGenericRawTextElement() + return true + } + p.addElement() + p.im = inHeadNoscriptIM + // Don't let the tokenizer go into raw text mode when scripting is disabled. + p.tokenizer.NextIsNotRawText() + return true + case a.Script, a.Title: + p.addElement() + p.setOriginalIM() + p.im = textIM + return true + case a.Noframes, a.Style: + p.parseGenericRawTextElement() + return true + case a.Head: + // Ignore the token. + return true + case a.Template: + p.addElement() + p.afe = append(p.afe, &scopeMarker) + p.framesetOK = false + p.im = inTemplateIM + p.templateStack = append(p.templateStack, inTemplateIM) + return true + } + case EndTagToken: + switch p.tok.DataAtom { + case a.Head: + p.oe.pop() + p.im = afterHeadIM + return true + case a.Body, a.Html, a.Br: + p.parseImpliedToken(EndTagToken, a.Head, a.Head.String()) + return false + case a.Template: + if !p.oe.contains(a.Template) { + return true + } + // TODO: remove this divergence from the HTML5 spec. + // + // See https://bugs.chromium.org/p/chromium/issues/detail?id=829668 + p.generateImpliedEndTags() + for i := len(p.oe) - 1; i >= 0; i-- { + if n := p.oe[i]; n.Namespace == "" && n.DataAtom == a.Template { + p.oe = p.oe[:i] + break + } + } + p.clearActiveFormattingElements() + p.templateStack.pop() + p.resetInsertionMode() + return true + default: + // Ignore the token. + return true + } + case CommentToken: + p.addChild(&Node{ + Type: CommentNode, + Data: p.tok.Data, + }) + return true + case DoctypeToken: + // Ignore the token. + return true + } + + p.parseImpliedToken(EndTagToken, a.Head, a.Head.String()) + return false +} + +// 12.2.6.4.5. +func inHeadNoscriptIM(p *parser) bool { + switch p.tok.Type { + case DoctypeToken: + // Ignore the token. + return true + case StartTagToken: + switch p.tok.DataAtom { + case a.Html: + return inBodyIM(p) + case a.Basefont, a.Bgsound, a.Link, a.Meta, a.Noframes, a.Style: + return inHeadIM(p) + case a.Head: + // Ignore the token. + return true + case a.Noscript: + // Don't let the tokenizer go into raw text mode even when a