WebKit HTML Element support process

Last Update:2018-12-05 Source: Internet

Author: User

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This section describes how WebKit parses HTML elements.

After documentloader receives HTML, it calls htmldocumentparser: appendbytes through documentwriter. After decoding by documentwriter, it calls htmldocumentparser: append to add it to htmlinputstream. If JavaScript code is currently being executed, call htmlpreloadparts to download some IMG and CSS resources in advance. If suspend is used, wait for htmlparserscheduler to resume, call htmltokenizer to obtain an htmltoken, and call htmltreebuilder to create Dom.
Tree. If a script needs to be run, give htmltreebuilder to pause. Then, run the script through htmlscriptrunner before obtaining the token next time.
The parsing process mainly involves htmltreebuilder. cpp, htmltokenizer. cpp, and htmldocumentparser. cpp. The setinsertionmode mainly records the resolution status.

Htmltokenizer provides the nexttoken method to parse htmlinputstream. Each call resolves a token (including the tagname and other attribute names and attribute values) and submits it to the processtoken method of htmltreebuilder for processing. The specific parsing process is as follows:

Suppose there are the following HTML files:

<HTML>

<Head>

</Head>

<Body>

Test

</Body>

</Html>

1. the tagname parsed to token is HTML and the type is starttag. It is handed to the processtoken method of htmltreebuilder for processing. processstarttag ----> defaultforinitial ---> setinsertionmode (beforehtmlmode) ---> token (token) ---> Create an HTML element (htmlhtmlelement class) object and m_openelements.pushhtmlhtmlelement ---> node. attach ()
2. parse the token type to character and hand it to the processtoken method of htmltreebuilder for processing. processcharacter (token)
3. the tagname resolved to the token is head, the type is starttag, and is handed over to the processtoken method of htmltreebuilder for processing. processstarttag ----> m_tree.inserthtmlheadelement (token) ---> Create head element (htmlheadelement class) and m_openelements.pushhtmlheadelement ---> node. attach ()
4. parse the token type to character and hand it to the processtoken method of htmltreebuilder for processing. processcharacter (token)
5. the tagname resolved to the token is link and the type is starttag. it is handed over to the processtoken method of htmltreebuilder for processing. processstarttag ---> processstarttagforinhead (token) ---> m_tree.insertselfclosinghtmlelement) ---> Create an object of The Link element (htmllinkelement class) and enter the htmllinkelement class for some actual operations, such as checking attributes and performing related operations based on existing attributes. ---> Node. Attach ()
6. parse the token type to character and hand it to the processtoken method of htmltreebuilder for processing. processcharacter (token)
7. the tagname resolved to the token is head, And the type is endtag. It is handed to the processtoken method of htmltreebuilder for processing. processendtag (token) ---> m_tree.openelements ()-> pophtmlheadelement () ---> setinsertionmode) ---> node. attach ()
8. parse the token type to character and hand it to the processtoken method of htmltreebuilder for processing. processcharacter (token)
9. the tagname resolved to the token is body and the type is starttag. it is handed over to the processtoken method of htmltreebuilder for processing. processstarttag (token) ---> m_framesetok = false ---> creates the body element (htmlbodyelement class) and pushhtmlbodyelement (attachtocurrent (Object of the Body element) ---> attach (currentnode (), body object) ---> node. attach ()
10. the token type is parsed to character and handed to the processtoken method of htmltreebuilder for processing. processcharacter (token) ---> processcharacterbuffer (buffer) ---> obtains the characters value as test ---> m_tree.inserttextnode) ---> attachatsite ---> text: attach () ---> node: createrendererifneeded () ---> node. attach ()
11. the tagname resolved to the token is body, and the type is endtag. The tagname is handed to the processtoken method of htmltreebuilder for processing. processendtag (token) ---> processendtagforinbody (token) ---> processbodyendtagforinbody) ---> setinsertionmode (afterbodymode)
12. parse the token type to character and hand it to the processtoken method of htmltreebuilder for processing. processcharacter (token) ---> processcharacterbuffer ---> m_tree.inserttextnode (characters)
13. The tagname resolved to the token is HTML, the type is endtag, and is handed to the processtoken method of htmltreebuilder for processing. processendtag (token) ---> processendtagforinbody (token) ---> setinsertionmode)
14. parse to the token type as endoffile and hand it to the processtoken method of htmltreebuilder for processing. processendoffile (token) ---> m_tree.openelements ()-> popall () to clear htmlelementstack.

I hope it will be useful to you. Currently, few people are engaged in WebKit ~~~.

HTML5 A labels attached

Attribute	Value	Description
Charset	Char_encoding	HTML 5 is not supported.
Coords	Coordinates	HTML 5 is not supported.
Href	URL	The target URL of the link.
Hreflang	Language_code	Specifies the reference language of the target URL. It is used only when the href attribute exists.
Media	Media Query	Specifies the media type of the target URL. Default Value: All. It is used only when the href attribute exists.
Name	Section_name	HTML 5 is not supported.
REL	Alternate Archives Author Bookmark Contact External First Help Icon Index Last License Next Nofollow Noreferrer Pingback Prefetch Prev Search Stylesheet Sidebar Tag Up	Specifies the relationship between the current document and the target URL. It is used only when the href attribute exists.
Rev	Text	HTML 5 is not supported.
Shape	Default Rect Circle Poly	HTML 5 is not supported.
Target	_ Blank _ Parent _ Self _ Top	Where to open the target URL. It is used only when the href attribute exists.
Type	Mime_type	Specifies the MIME type of the target URL. It is used only when the href attribute exists. Note: mime = Multipurpose Internet Mail Extensions.

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