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849b4ec9e9
it was far down on the roadmap, but implemented earlier, because it's interesting, and to help prepare for a jmap implementation. for jmap we need to implement more client-like functionality than with just imap. internal data structures need to change. jmap has lots of other requirements, so it's already a big project. by implementing a webmail now, some of the required data structure changes become clear and can be made now, so the later jmap implementation can do things similarly to the webmail code. the webmail frontend and webmail are written together, making their interface/api much smaller and simpler than jmap. one of the internal changes is that we now keep track of per-mailbox total/unread/unseen/deleted message counts and mailbox sizes. keeping this data consistent after any change to the stored messages (through the code base) is tricky, so mox now has a consistency check that verifies the counts are correct, which runs only during tests, each time an internal account reference is closed. we have a few more internal "changes" that are propagated for the webmail frontend (that imap doesn't have a way to propagate on a connection), like changes to the special-use flags on mailboxes, and used keywords in a mailbox. more changes that will be required have revealed themselves while implementing the webmail, and will be implemented next. the webmail user interface is modeled after the mail clients i use or have used: thunderbird, macos mail, mutt; and webmails i normally only use for testing: gmail, proton, yahoo, outlook. a somewhat technical user is assumed, but still the goal is to make this webmail client easy to use for everyone. the user interface looks like most other mail clients: a list of mailboxes, a search bar, a message list view, and message details. there is a top/bottom and a left/right layout for the list/message view, default is automatic based on screen size. the panes can be resized by the user. buttons for actions are just text, not icons. clicking a button briefly shows the shortcut for the action in the bottom right, helping with learning to operate quickly. any text that is underdotted has a title attribute that causes more information to be displayed, e.g. what a button does or a field is about. to highlight potential phishing attempts, any text (anywhere in the webclient) that switches unicode "blocks" (a rough approximation to (language) scripts) within a word is underlined orange. multiple messages can be selected with familiar ui interaction: clicking while holding control and/or shift keys. keyboard navigation works with arrows/page up/down and home/end keys, and also with a few basic vi-like keys for list/message navigation. we prefer showing the text instead of html (with inlined images only) version of a message. html messages are shown in an iframe served from an endpoint with CSP headers to prevent dangerous resources (scripts, external images) from being loaded. the html is also sanitized, with javascript removed. a user can choose to load external resources (e.g. images for tracking purposes). the frontend is just (strict) typescript, no external frameworks. all incoming/outgoing data is typechecked, both the api request parameters and response types, and the data coming in over SSE. the types and checking code are generated with sherpats, which uses the api definitions generated by sherpadoc based on the Go code. so types from the backend are automatically propagated to the frontend. since there is no framework to automatically propagate properties and rerender components, changes coming in over the SSE connection are propagated explicitly with regular function calls. the ui is separated into "views", each with a "root" dom element that is added to the visible document. these views have additional functions for getting changes propagated, often resulting in the view updating its (internal) ui state (dom). we keep the frontend compilation simple, it's just a few typescript files that get compiled (combined and types stripped) into a single js file, no additional runtime code needed or complicated build processes used. the webmail is served is served from a compressed, cachable html file that includes style and the javascript, currently just over 225kb uncompressed, under 60kb compressed (not minified, including comments). we include the generated js files in the repository, to keep Go's easily buildable self-contained binaries. authentication is basic http, as with the account and admin pages. most data comes in over one long-term SSE connection to the backend. api requests signal which mailbox/search/messages are requested over the SSE connection. fetching individual messages, and making changes, are done through api calls. the operations are similar to imap, so some code has been moved from package imapserver to package store. the future jmap implementation will benefit from these changes too. more functionality will probably be moved to the store package in the future. the quickstart enables webmail on the internal listener by default (for new installs). users can enable it on the public listener if they want to. mox localserve enables it too. to enable webmail on existing installs, add settings like the following to the listeners in mox.conf, similar to AccountHTTP(S): WebmailHTTP: Enabled: true WebmailHTTPS: Enabled: true special thanks to liesbeth, gerben, andrii for early user feedback. there is plenty still to do, see the list at the top of webmail/webmail.ts. feedback welcome as always.
293 lines
7.7 KiB
Go
293 lines
7.7 KiB
Go
// Copyright 2011 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package html
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import (
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"bufio"
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"errors"
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"fmt"
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"io"
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"strings"
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)
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type writer interface {
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io.Writer
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io.ByteWriter
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WriteString(string) (int, error)
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}
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// Render renders the parse tree n to the given writer.
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//
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// Rendering is done on a 'best effort' basis: calling Parse on the output of
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// Render will always result in something similar to the original tree, but it
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// is not necessarily an exact clone unless the original tree was 'well-formed'.
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// 'Well-formed' is not easily specified; the HTML5 specification is
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// complicated.
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//
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// Calling Parse on arbitrary input typically results in a 'well-formed' parse
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// tree. However, it is possible for Parse to yield a 'badly-formed' parse tree.
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// For example, in a 'well-formed' parse tree, no <a> element is a child of
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// another <a> element: parsing "<a><a>" results in two sibling elements.
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// Similarly, in a 'well-formed' parse tree, no <a> element is a child of a
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// <table> element: parsing "<p><table><a>" results in a <p> with two sibling
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// children; the <a> is reparented to the <table>'s parent. However, calling
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// Parse on "<a><table><a>" does not return an error, but the result has an <a>
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// element with an <a> child, and is therefore not 'well-formed'.
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//
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// Programmatically constructed trees are typically also 'well-formed', but it
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// is possible to construct a tree that looks innocuous but, when rendered and
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// re-parsed, results in a different tree. A simple example is that a solitary
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// text node would become a tree containing <html>, <head> and <body> elements.
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// Another example is that the programmatic equivalent of "a<head>b</head>c"
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// becomes "<html><head><head/><body>abc</body></html>".
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func Render(w io.Writer, n *Node) error {
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if x, ok := w.(writer); ok {
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return render(x, n)
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}
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buf := bufio.NewWriter(w)
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if err := render(buf, n); err != nil {
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return err
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}
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return buf.Flush()
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}
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// plaintextAbort is returned from render1 when a <plaintext> element
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// has been rendered. No more end tags should be rendered after that.
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var plaintextAbort = errors.New("html: internal error (plaintext abort)")
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func render(w writer, n *Node) error {
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err := render1(w, n)
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if err == plaintextAbort {
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err = nil
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}
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return err
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}
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func render1(w writer, n *Node) error {
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// Render non-element nodes; these are the easy cases.
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switch n.Type {
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case ErrorNode:
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return errors.New("html: cannot render an ErrorNode node")
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case TextNode:
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return escape(w, n.Data)
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case DocumentNode:
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for c := n.FirstChild; c != nil; c = c.NextSibling {
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if err := render1(w, c); err != nil {
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return err
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}
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}
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return nil
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case ElementNode:
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// No-op.
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case CommentNode:
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if _, err := w.WriteString("<!--"); err != nil {
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return err
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}
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if err := escapeComment(w, n.Data); err != nil {
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return err
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}
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if _, err := w.WriteString("-->"); err != nil {
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return err
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}
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return nil
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case DoctypeNode:
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if _, err := w.WriteString("<!DOCTYPE "); err != nil {
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return err
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}
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if err := escape(w, n.Data); err != nil {
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return err
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}
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if n.Attr != nil {
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var p, s string
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for _, a := range n.Attr {
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switch a.Key {
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case "public":
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p = a.Val
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case "system":
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s = a.Val
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}
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}
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if p != "" {
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if _, err := w.WriteString(" PUBLIC "); err != nil {
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return err
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}
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if err := writeQuoted(w, p); err != nil {
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return err
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}
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if s != "" {
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if err := w.WriteByte(' '); err != nil {
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return err
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}
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if err := writeQuoted(w, s); err != nil {
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return err
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}
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}
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} else if s != "" {
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if _, err := w.WriteString(" SYSTEM "); err != nil {
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return err
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}
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if err := writeQuoted(w, s); err != nil {
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return err
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}
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}
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}
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return w.WriteByte('>')
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case RawNode:
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_, err := w.WriteString(n.Data)
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return err
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default:
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return errors.New("html: unknown node type")
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}
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// Render the <xxx> opening tag.
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if err := w.WriteByte('<'); err != nil {
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return err
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}
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if _, err := w.WriteString(n.Data); err != nil {
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return err
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}
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for _, a := range n.Attr {
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if err := w.WriteByte(' '); err != nil {
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return err
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}
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if a.Namespace != "" {
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if _, err := w.WriteString(a.Namespace); err != nil {
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return err
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}
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if err := w.WriteByte(':'); err != nil {
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return err
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}
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}
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if _, err := w.WriteString(a.Key); err != nil {
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return err
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}
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if _, err := w.WriteString(`="`); err != nil {
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return err
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}
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if err := escape(w, a.Val); err != nil {
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return err
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}
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if err := w.WriteByte('"'); err != nil {
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return err
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}
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}
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if voidElements[n.Data] {
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if n.FirstChild != nil {
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return fmt.Errorf("html: void element <%s> has child nodes", n.Data)
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}
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_, err := w.WriteString("/>")
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return err
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}
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if err := w.WriteByte('>'); err != nil {
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return err
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}
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// Add initial newline where there is danger of a newline beging ignored.
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if c := n.FirstChild; c != nil && c.Type == TextNode && strings.HasPrefix(c.Data, "\n") {
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switch n.Data {
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case "pre", "listing", "textarea":
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if err := w.WriteByte('\n'); err != nil {
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return err
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}
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}
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}
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// Render any child nodes
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if childTextNodesAreLiteral(n) {
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for c := n.FirstChild; c != nil; c = c.NextSibling {
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if c.Type == TextNode {
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if _, err := w.WriteString(c.Data); err != nil {
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return err
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}
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} else {
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if err := render1(w, c); err != nil {
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return err
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}
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}
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}
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if n.Data == "plaintext" {
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// Don't render anything else. <plaintext> must be the
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// last element in the file, with no closing tag.
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return plaintextAbort
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}
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} else {
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for c := n.FirstChild; c != nil; c = c.NextSibling {
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if err := render1(w, c); err != nil {
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return err
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}
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}
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}
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// Render the </xxx> closing tag.
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if _, err := w.WriteString("</"); err != nil {
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return err
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}
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if _, err := w.WriteString(n.Data); err != nil {
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return err
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}
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return w.WriteByte('>')
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}
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func childTextNodesAreLiteral(n *Node) bool {
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// Per WHATWG HTML 13.3, if the parent of the current node is a style,
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// script, xmp, iframe, noembed, noframes, or plaintext element, and the
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// current node is a text node, append the value of the node's data
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// literally. The specification is not explicit about it, but we only
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// enforce this if we are in the HTML namespace (i.e. when the namespace is
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// "").
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// NOTE: we also always include noscript elements, although the
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// specification states that they should only be rendered as such if
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// scripting is enabled for the node (which is not something we track).
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if n.Namespace != "" {
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return false
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}
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switch n.Data {
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case "iframe", "noembed", "noframes", "noscript", "plaintext", "script", "style", "xmp":
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return true
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default:
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return false
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}
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}
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// writeQuoted writes s to w surrounded by quotes. Normally it will use double
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// quotes, but if s contains a double quote, it will use single quotes.
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// It is used for writing the identifiers in a doctype declaration.
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// In valid HTML, they can't contain both types of quotes.
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func writeQuoted(w writer, s string) error {
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var q byte = '"'
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if strings.Contains(s, `"`) {
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q = '\''
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}
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if err := w.WriteByte(q); err != nil {
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return err
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}
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if _, err := w.WriteString(s); err != nil {
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return err
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}
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if err := w.WriteByte(q); err != nil {
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return err
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}
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return nil
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}
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// Section 12.1.2, "Elements", gives this list of void elements. Void elements
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// are those that can't have any contents.
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var voidElements = map[string]bool{
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"area": true,
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"base": true,
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"br": true,
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"col": true,
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"embed": true,
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"hr": true,
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"img": true,
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"input": true,
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"keygen": true, // "keygen" has been removed from the spec, but are kept here for backwards compatibility.
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"link": true,
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"meta": true,
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"param": true,
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"source": true,
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"track": true,
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"wbr": true,
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}
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