From c90f36e3dd179d2de96f4f5fe38d8dc9a9de6dfe Mon Sep 17 00:00:00 2001 From: Emile Date: Fri, 25 Oct 2024 15:55:50 +0200 Subject: vendor --- vendor/golang.org/x/net/html/render.go | 293 +++++++++++++++++++++++++++++++++ 1 file changed, 293 insertions(+) create mode 100644 vendor/golang.org/x/net/html/render.go (limited to 'vendor/golang.org/x/net/html/render.go') diff --git a/vendor/golang.org/x/net/html/render.go b/vendor/golang.org/x/net/html/render.go new file mode 100644 index 0000000..e8c1233 --- /dev/null +++ b/vendor/golang.org/x/net/html/render.go @@ -0,0 +1,293 @@ +// 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 html + +import ( + "bufio" + "errors" + "fmt" + "io" + "strings" +) + +type writer interface { + io.Writer + io.ByteWriter + WriteString(string) (int, error) +} + +// Render renders the parse tree n to the given writer. +// +// Rendering is done on a 'best effort' basis: calling Parse on the output of +// Render will always result in something similar to the original tree, but it +// is not necessarily an exact clone unless the original tree was 'well-formed'. +// 'Well-formed' is not easily specified; the HTML5 specification is +// complicated. +// +// Calling Parse on arbitrary input typically results in a 'well-formed' parse +// tree. However, it is possible for Parse to yield a 'badly-formed' parse tree. +// For example, in a 'well-formed' parse tree, no element is a child of +// another element: parsing "" results in two sibling elements. +// Similarly, in a 'well-formed' parse tree, no element is a child of a +// element: parsing "

with two sibling +// children; the is reparented to the

's parent. However, calling +// Parse on "

" does not return an error, but the result has an +// element with an child, and is therefore not 'well-formed'. +// +// Programmatically constructed trees are typically also 'well-formed', but it +// is possible to construct a tree that looks innocuous but, when rendered and +// re-parsed, results in a different tree. A simple example is that a solitary +// text node would become a tree containing , and elements. +// Another example is that the programmatic equivalent of "abc" +// becomes "abc". +func Render(w io.Writer, n *Node) error { + if x, ok := w.(writer); ok { + return render(x, n) + } + buf := bufio.NewWriter(w) + if err := render(buf, n); err != nil { + return err + } + return buf.Flush() +} + +// plaintextAbort is returned from render1 when a element +// has been rendered. No more end tags should be rendered after that. +var plaintextAbort = errors.New("html: internal error (plaintext abort)") + +func render(w writer, n *Node) error { + err := render1(w, n) + if err == plaintextAbort { + err = nil + } + return err +} + +func render1(w writer, n *Node) error { + // Render non-element nodes; these are the easy cases. + switch n.Type { + case ErrorNode: + return errors.New("html: cannot render an ErrorNode node") + case TextNode: + return escape(w, n.Data) + case DocumentNode: + for c := n.FirstChild; c != nil; c = c.NextSibling { + if err := render1(w, c); err != nil { + return err + } + } + return nil + case ElementNode: + // No-op. + case CommentNode: + if _, err := w.WriteString(""); err != nil { + return err + } + return nil + case DoctypeNode: + if _, err := w.WriteString("<!DOCTYPE "); err != nil { + return err + } + if err := escape(w, n.Data); err != nil { + return err + } + if n.Attr != nil { + var p, s string + for _, a := range n.Attr { + switch a.Key { + case "public": + p = a.Val + case "system": + s = a.Val + } + } + if p != "" { + if _, err := w.WriteString(" PUBLIC "); err != nil { + return err + } + if err := writeQuoted(w, p); err != nil { + return err + } + if s != "" { + if err := w.WriteByte(' '); err != nil { + return err + } + if err := writeQuoted(w, s); err != nil { + return err + } + } + } else if s != "" { + if _, err := w.WriteString(" SYSTEM "); err != nil { + return err + } + if err := writeQuoted(w, s); err != nil { + return err + } + } + } + return w.WriteByte('>') + case RawNode: + _, err := w.WriteString(n.Data) + return err + default: + return errors.New("html: unknown node type") + } + + // Render the <xxx> opening tag. + if err := w.WriteByte('<'); err != nil { + return err + } + if _, err := w.WriteString(n.Data); err != nil { + return err + } + for _, a := range n.Attr { + if err := w.WriteByte(' '); err != nil { + return err + } + if a.Namespace != "" { + if _, err := w.WriteString(a.Namespace); err != nil { + return err + } + if err := w.WriteByte(':'); err != nil { + return err + } + } + if _, err := w.WriteString(a.Key); err != nil { + return err + } + if _, err := w.WriteString(`="`); err != nil { + return err + } + if err := escape(w, a.Val); err != nil { + return err + } + if err := w.WriteByte('"'); err != nil { + return err + } + } + if voidElements[n.Data] { + if n.FirstChild != nil { + return fmt.Errorf("html: void element <%s> has child nodes", n.Data) + } + _, err := w.WriteString("/>") + return err + } + if err := w.WriteByte('>'); err != nil { + return err + } + + // Add initial newline where there is danger of a newline beging ignored. + if c := n.FirstChild; c != nil && c.Type == TextNode && strings.HasPrefix(c.Data, "\n") { + switch n.Data { + case "pre", "listing", "textarea": + if err := w.WriteByte('\n'); err != nil { + return err + } + } + } + + // Render any child nodes + if childTextNodesAreLiteral(n) { + for c := n.FirstChild; c != nil; c = c.NextSibling { + if c.Type == TextNode { + if _, err := w.WriteString(c.Data); err != nil { + return err + } + } else { + if err := render1(w, c); err != nil { + return err + } + } + } + if n.Data == "plaintext" { + // Don't render anything else. <plaintext> must be the + // last element in the file, with no closing tag. + return plaintextAbort + } + } else { + for c := n.FirstChild; c != nil; c = c.NextSibling { + if err := render1(w, c); err != nil { + return err + } + } + } + + // Render the </xxx> closing tag. + if _, err := w.WriteString("</"); err != nil { + return err + } + if _, err := w.WriteString(n.Data); err != nil { + return err + } + return w.WriteByte('>') +} + +func childTextNodesAreLiteral(n *Node) bool { + // Per WHATWG HTML 13.3, if the parent of the current node is a style, + // script, xmp, iframe, noembed, noframes, or plaintext element, and the + // current node is a text node, append the value of the node's data + // literally. The specification is not explicit about it, but we only + // enforce this if we are in the HTML namespace (i.e. when the namespace is + // ""). + // NOTE: we also always include noscript elements, although the + // specification states that they should only be rendered as such if + // scripting is enabled for the node (which is not something we track). + if n.Namespace != "" { + return false + } + switch n.Data { + case "iframe", "noembed", "noframes", "noscript", "plaintext", "script", "style", "xmp": + return true + default: + return false + } +} + +// writeQuoted writes s to w surrounded by quotes. Normally it will use double +// quotes, but if s contains a double quote, it will use single quotes. +// It is used for writing the identifiers in a doctype declaration. +// In valid HTML, they can't contain both types of quotes. +func writeQuoted(w writer, s string) error { + var q byte = '"' + if strings.Contains(s, `"`) { + q = '\'' + } + if err := w.WriteByte(q); err != nil { + return err + } + if _, err := w.WriteString(s); err != nil { + return err + } + if err := w.WriteByte(q); err != nil { + return err + } + return nil +} + +// Section 12.1.2, "Elements", gives this list of void elements. Void elements +// are those that can't have any contents. +var voidElements = map[string]bool{ + "area": true, + "base": true, + "br": true, + "col": true, + "embed": true, + "hr": true, + "img": true, + "input": true, + "keygen": true, // "keygen" has been removed from the spec, but are kept here for backwards compatibility. + "link": true, + "meta": true, + "param": true, + "source": true, + "track": true, + "wbr": true, +} -- cgit 1.4.1