The HTML Processor has only supported a specific kind of parsing mode
called _the fragment parsing mode_, where it behaves in the same way
that `node.innerHTML = html` does in the DOM. This mode assumes a
context node and doesn't support parsing an entire document.
As part of work to add more spec support to the HTML API, this patch
introduces a full parsing mode, which can parse a full HTML document
from start to end, including the doctype declaration and head tags.
Developed in https://github.com/wordpress/wordpress-develop/pull/6977
Discussed in https://core.trac.wordpress.org/ticket/61576
Props: dmsnell, jonsurrell.
See #61576.
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Insertion modes in an HTML parser may include instructions like "process
the token in the IN HEAD insertion mode." The rules do not change the
insertion mode of the parser, but the errors are triggered outside of the
rules for the current insertion mode. These will be misleading when
bailing on these instructions, because it will point someone to the wrong
place in the code to find the source of the error.
In this patch all of the bail-points due to lacking insertion mode support
are hard-coded to better orient someone to the section of the code lacking
support for handling the input HTML.
Developed in https://github.com/wordpress/wordpress-develop/pull/7043
Discussed in https://core.trac.wordpress.org/ticket/61576
Follow-up to [58679].
Props: dmsnell, jonsurrell.
See #61576.
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In part of a larger review of CSS semantics and behaviors, this patch
takes the opportunity to remove leading whitespace in an updated class
attribute after the first class in the attribute has been removed.
Previously, if the first class name had been removed, the whitespace
that formerly followed it would remain in the class attribute. This
stood in contrast to removing other class names, which removed their
associated whitespace.
There should be no semantic or functional changes in this patch, only
a slightly-large diff for modified HTML documents that looks prettier
when removing the first class name in a class attribute.
Developed in https://github.com/WordPress/wordpress-develop/pull/6933
Discussed in https://core.trac.wordpress.org/ticket/61531
Props dmsnell, jonsurrell.
See #61531.
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The HTML Processor internally throws an exception when it reaches HTML
that it knows it cannot process, but this exception is not made
available to calling code. It can be useful to extract more knowledge
about why it gave up, especially for debugging purposes.
In this patch, more context is added to the WP_HTML_Unsupported_Exception
and the last exception is made available to calling code through a new
method, `get_unsupported_exception()`.
Developed in https://github.com/WordPress/wordpress-develop/pull/6985
Discussed in https://core.trac.wordpress.org/ticket/61646
Props bernhard-reiter, dmsnell, jonsurrell.
See #61646.
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Since the HTML Processor started visiting all nodes in a document, both
real and virtual, the breadcrumb accounting became a bit complicated
and it's not entirely clear that it is fully reliable.
In this patch the breadcrumbs are rebuilt separately from the stack of
open elements in order to eliminate the problem of the stateful stack
interactions and the post-hoc event queue.
Breadcrumbs are greatly simplified as a result, and more verifiably
correct, in this construction.
Developed in https://github.com/WordPress/wordpress-develop/pull/6981
Discussed in https://core.trac.wordpress.org/ticket/61576
Follow-up to [58590].
Props bernhard-reiter, dmsnell.
See #61576.
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In order to add support for the SELECT and TABLE tags in the HTML Processor, it
needs to implement the HTML algorithm named "reset the insertion mode
appropriately".
This patch implements that algorithm to unblock the additional tag support. The
algorithm resets the parsing mode after specific state changes in complicated
situations where alternative rules are in effect (such as rules governing how
the parser handles tags found within a TABLE element).
Developed in https://github.com/WordPress/wordpress-develop/pull/6020
Discussed in https://core.trac.wordpress.org/ticket/61549
Props dmsnell, jonsurrell.
Fixes#61549.
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When [58304] introduced the abililty to visit virtual nodes in the HTML document,
those being the nodes which are implied by the HTML but no explicitly present in
the raw text, a bug was introduced in the `get_breadcrumbs()` method because it
wasn't updated to be aware of the virtual nodes. Therefore it would report the
wrong breadcrumbs for virtual nodes. Since the new `get_depth()` method is based
on the same logic it was also broken for virtual nodes.
In this patch, the breadcrumbs have been updated to account for the virtual nodes
and the depth method has been updated to rely on the fixed breadcrumb logic.
Developed in https://github.com/WordPress/wordpress-develop/pull/6914
Discussed in https://core.trac.wordpress.org/ticket/61348
Follow-up to [58304].
Props dmsnell, jonsurrell, zieladam.
See #61348.
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This patch introduces two related changes:
- It adds missing subclass methods on the HTML Processor which needed
to be implemented since it started visiting virtual nodes. These
methods need to account for the fact that not all tokens truly exist.
- It adds a new concept and internal method, `is_virtual()`, indicating
if the currently-matched token comes from the raw text in the input
HTML document or if it was the byproduct of semantic parsing rules.
This internal method and new vocabulary around token provenance
considerably simplifies the logic spread throughout the rest of the
class and its subclass methods.
Developed in https://github.com/WordPress/wordpress-develop/pull/6860
Discussed in https://core.trac.wordpress.org/ticket/61348
Follow-up to [58304].
Props dmsnell, jonsurrell, gziolo.
See #61348.
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When the `WP_HTML_Processor` was introduced with its `::create_fragment()`
static creator method, that method has been returning a `new self(...)`.
Unfortunately, this means that subclasses cannot use that method since it
will return the `WP_HTML_Processor` instead of the subclass.
With this patch, the static creator method returns `new static(...)` to preserve
the intended behavior. A new test asserts this behavior for future changes.
Developed in https://github.com/WordPress/wordpress-develop/pull/6729
Discussed in https://core.trac.wordpress.org/ticket/61374
Props dmsnell, jonsurrell.
Follow-up to [56274].
Fixes#61374.
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HTML is a kind of short-hand for a DOM structure. This means that there are
many cases in HTML where an element's opening tag or closing tag is missing (or
both). This is because many of the parsing rules imply creating elements in the
DOM which may not exist in the text of the HTML.
The HTML Processor, being the higher-level counterpart to the Tag Processor, is
already aware of these nodes, but since it's inception has not paused on them
when scanning through a document. Instead, these are visible when pausing on a
child of such an element, but otherwise not seen.
In this patch the HTML Processor starts exposing those implicitly-created nodes,
including opening tags, and closing tags, that aren't foudn in the text content
of the HTML input document.
Previously, the sequence of matched tokens when scanning with
`WP_HTML_Processor::next_token()` would depend on how the HTML document was written,
but with this patch, all semantically equal HTML documents will parse and scan in
the same exact manner, presenting an idealized or "perfect" view of the document
the same way as would occur when traversing a DOM in a browser.
Developed in https://github.com/WordPress/wordpress-develop/pull/6348
Discussed in https://core.trac.wordpress.org/ticket/61348
Props audrasjb, dmsnell, gziolo, jonsurrell.
Fixes#61348.
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Provides a custom decoder for strings coming from HTML attributes and
markup. This custom decoder is necessary because of deficiencies in
PHP's `html_entity_decode()` function:
- It isn't aware of 720 of the possible named character references in
HTML, leaving many out that should be translated.
- It isn't aware of the ambiguous ampersand rule, which allows
conversion of character references in certain contexts when they
are missing their closing `;`.
- It doesn't draw a distinction for the ambiguous ampersand rule
when decoding attribute values instead of markup values.
- Use of `html_entity_decode()` requires manually passing non-default
paramter values to ensure it decodes properly.
This decoder also provides some conveniences, such as making a
single-pass and interruptable decode operation possible. This will
provide a number of opportunities to optimize detection and decoding
of things like value prefixes, and whether a value contains a given
substring.
Developed in https://github.com/WordPress/wordpress-develop/pull/6387
Discussed in https://core.trac.wordpress.org/ticket/61072
Props dmsnell, gziolo, jonsurrell, jorbin, westonruter, zieladam.
Fixes#61072.
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The Tag Processor stores the byte-offsets into its HTML document where
the current token starts and ends, and also for every bookmark. In some
cases for tags, the end offset has been off by one.
In this patch the offset is fixed so that a bookmark always properly
refers to the full span of the token it's bookmarking. Also the current
token byte offsets are properly recorded.
While this is a defect in the Tag Processor, it hasn't been exposed
through the public interface and has not affected any of the working
of the processor. Only subclasses which rely on the length of a bookmark
have been potentially affected, and these are not supported environments
in the ongoing work.
This fix is important for future work and for ensuring that subclasses
performing custom behaviors remain as reliable as the public interface.
Developed in https://github.com/WordPress/wordpress-develop/pull/6625
Discussed in https://core.trac.wordpress.org/ticket/61301
Props dmsnell, gziolo, jonsurrell, westonruter.
Fixes#61301.
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This patch adds a new method, `WP_HTML_Processor->expects_closer()` to indicate
if the currently-matched node expects to find a closing token. For example, a
`DIV` element expects a closing `</div>` tag, but an `<img>` expects none, because
it's a void element. Similarly, `#text` nodes and HTML comments only appear as
unitary nodes on the stack of open elements. Once proceeding further in the
document they are immediately removed without any closing tag.
This new method serves as a helper to indicate whether or not to expect the
closer, as this can be more complicated than it seems, and calling code
shouldn't have to build custom interpretations and implementations. Instead,
the HTML Processor ought to export its internal knowledge to make it easy for
consuming code and projects.
Developed in https://github.com/WordPress/wordpress-develop/pull/6600
Discussed in https://core.trac.wordpress.org/ticket/61257Fixes#61257.
Props dmsnell, jonsurrell.
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The HTML Processor maintains a stack of open elements, where every element,
every `#text` node, every HTML comment, and other node is pushed and popped while
traversing the document. The "depth" of each of these nodes represents how deep
that stack is where the node appears. Unfortunately this information isn't
exposed to calling code, which has led different projects to attempt to
calculate this value externally. This isn't always trivial, but the HTML
Processor could make it so by exposing the internal knowledge in a new method.
In this patch the `get_current_depth()` method returns just that. Since the
processor always exists within a context, the depth includes nesting from the
always-present html element and also the body, since currently the HTML
Processor only supports parsing in the IN BODY context.
This means that the depth reported for the `DIV` in `<div>` is 3, not 1, because
its breadcrumbs path is `HTML > BODY > DIV`.
Developed in https://github.com/WordPress/wordpress-develop/pull/6589
Discussed in https://core.trac.wordpress.org/ticket/61255Fixes#61255.
Props dmsnell, jonsurrell.
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Since [60428] the Tag Processor has been misidentifying single-character
funky comments. It has been asserting that the full token-length for a
funky comment must be at least three characters after the opening (e.g.
`</1>`), but it has been starting to look for the closing `>` after
those same three characters. This means that it has been skipping the
actual close of these funky comments and swallowing up the next syntax
until it finds a `>`, often consuming the next tag in the process.
This patch fixes the detector and restores finding the following token.
Developed in https://github.com/WordPress/wordpress-develop/pull/6412
Discussed in https://core.trac.wordpress.org/ticket/60170
Follow-up to [60428].
Fixes#60170.
Props dmsnell, gziolo, jonsurrell.
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When encountering text nodes in an HTML document, the HTML parser needs
to run the active format reconstruction algorithm, even if it doesn't
stop to visit those text nodes. This is because the formats, which might
need reconstructing, will impact the breadcrumbs of all downstream nodes
from the text node.
In this patch, this process is triggered, which properly triggers the
active format reconstruction. It also enables the visiting of other token
types as is possible in the Tag Processor.
Developed in https://github.com/WordPress/wordpress-develop/pull/6054
Discussed in https://core.trac.wordpress.org/ticket/60170
Props: dmsnell, jonsurrell, westonruter.
Fixes: #60455.
Follow-up to: [57348].
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When making repeated updates to a document, the Tag Processor will end
up copying the entire document once for every update. This can lead to
catastrophic behavior in the worse case.
However, when batch-applying updates it's able to copy chunks of the
document in one thread and only end up copying the entire document once
for the entire batch.
Previously the Tag Processor has been eagerly applying udpates, but in
this patch it defers applying those updates as long as is possible.
Developed in https://github.com/WordPress/wordpress-develop/pull/6120
Discussed in https://core.trac.wordpress.org/ticket/60697
Props: dmsnell, bernhard-reiter, jonsurrell, westonruter.
Fixes#60697.
Follow-up to [55706], [56941], [57348].
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In some cases, it's possible to seek back into a location found inside
an element which has been closed before the point in the document where
the `seek()` was made. In these cases the breadcrumb stack is lost, and
calling `get_breadcrumbs()` after the seek will return the wrong information.
In this patch, the HTML Processor takes a conservative approach and
moves to the front of the document, then reparses the document until
it reaches the sought-after location. This ensures consistency on
the stack of open elements and active formats, and preserves
breadcrumbs.
Developed in https://github.com/WordPress/wordpress-develop/pull/6185
Discussed in https://core.trac.wordpress.org/ticket/60687
Props jonsurrell.
Follow-up to [60687].
See #58517.
Fixes#60687.
Built from https://develop.svn.wordpress.org/trunk@57768
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When returning modifiable text in the HTML API, if the text segment
coerces to `false` inside `empty()`, then an empty string has been
returned instead of the string itself. For example, the text node in the
following HTML snippet:
{{{
<div>0</div>
}}}
In this patch the `empty()` check is removed. The purpose of the original
check was to skip further processing if the text content is empty, but
the check is not needed and the additioanl processing is minimal.
Removing the code removes the defect and leaves a cleaner method in its
absence.
Developed in https://github.com/WordPress/wordpress-develop/pull/6199
Follow-up to [57348]
Follow-up to #60170
Built from https://develop.svn.wordpress.org/trunk@57738
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The WP_HTML_Processor::has_bookmark() method has not correctly reported bookmarks
which have been set, because it wraps the given bookmark names when setting them.
Additionally, WP_HTML_Processor::seek() does not seek to correct location if HTML
has been updated because it wasn't flushing enqueued updates to the document.
In this patch both problems are resolved and added tests guard these behaviors
against future regressions.
Developed in https://github.com/WordPress/wordpress-develop/pull/6039
Discussed in https://core.trac.wordpress.org/ticket/60474
Follow-up to [56274].
Props dmsnell, jonsurrell.
Fixes#60474.
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A fix was introduced to the Tag Processor to ensure that contiguous text
in an HTML document emerges as a single text node spanning the full
sequence. Unfortunately, that patch was marginally over-zealous in
checking if a "<" started a syntax token or not. It used the following:
{{{
<?php
if ( 'A' <= $c && 'z' >= $c ) { ... }
}}}
This was based on the assumption that the A-Z and a-z letters are
contiguous in the ASCII range; they aren't, and there's a gap of
several characters in between. The result of this is that in some
cases the parser created a text boundary when it didn't need to.
Text boundaries can be surprising and can be created when reaching
invalid syntax, HTML comments, and more hidden elements, so
semantically this wasn't a major bug, but it was an aesthetic
challenge.
In this patch the check is properly compared for both upper- and
lower-case variants that could potentially form tag names.
{{{
<?php
if ( ( 'A' <= $c && 'Z' >= $c ) || ( 'a' <= $c && 'z' >= $c ) ) { ... }
}}}
This solves the problem and ensures that contiguous text appears
as a single text node when scanning tokens.
Developed in https://github.com/WordPress/wordpress-develop/pull/6041
Discussed in https://core.trac.wordpress.org/ticket/60385
Follow-up to [57489]
Props dmsnell, jonsurrell
Fixes#60385
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The HTML Processor tracks whether a token was found with the self-closing flag.
Depending on the context, this flag may or may not indicate that the element is
self closing. Unfortunately it's been tracking the wrong flag: it's been tracking
the end-tag flag, which indicates that a token is an end tag.
In this patch the right flag is set in the HTML Processor. This hasn't been an
issue because the HTML Processor doesn't yet read that stored flag, but it's an
important fix to make before adding support for foreign content (SVG and MathML)
since that behavior depends on reading the correct flag.
Follow-up to [56274].
Props dmsnell.
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When `next_token()` was introduced, it introduced a regression in the HTML
Processor whereby void tags remain on the stack of open elements when they
shouldn't. This led to invalid values returned from `get_breadcrumbs()`.
The reason was that calling `next_token()` works through a different code path
than the HTML Processor runs everything else. To solve this, its sub-classed
`next_token()` called `step( self::REPROCESS_CURRENT_TOKEN )` so that the proper
HTML accounting takes place.
Unfortunately that same reprocessing code path skipped the step whereby void
and self-closing elements are popped from the stack of open elements.
In this patch, that step is run with a third mode for `step()`, which is the
new `self::PROCESS_CURRENT_TOKEN`. This mode acts as if `self::PROCESS_NEXT_NODE`
were called, except it doesn't advance the parser.
Developed in https://github.com/WordPress/wordpress-develop/pull/5975
Discussed in https://core.trac.wordpress.org/ticket/60382
Follow-up to [57348]
Props dmsnell, jonsurrell
Fixes#60382
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When `next_token()` was introduced to the HTML Tag Processor, it started
classifying comments that look like they were intended to be CDATA sections.
In one of the changes made during development, however, a typo slipped
through code review that treated comments as CDATA even if they only
ended in `]>` and not the required `]]>`.
The consequences of this defect were minor because in all cases these are
treated as HTML comments from invalid syntax, but this patch adds the
missing check to ensure the proper reporting of CDATA-lookalikes.
Follow-up to [57348]
Props jonsurrell
Fixes#60406
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When `next_token()` was introduced, it brought a subtle bug. When encountering a `<` in the HTML stream which did not lead to a tag or comment or other token, it was treating the full text span to that point as one text node, and the following span another text node.
The entire span should be one text node.
In this patch the Tag Processor properly detects this scenario and combines the spans into one text node.
Follow-up to [57348]
Props jonsurrell
Fixes#60385
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Since its introduction in WordPress 6.2 the HTML Tag Processor has
provided a way to scan through all of the HTML tags in a document and
then read and modify their attributes. In order to reliably do this, it
also needed to be aware of other kinds of HTML syntax, but it didn't
expose those syntax tokens to consumers of the API.
In this patch the Tag Processor introduces a new scanning method and a
few helper methods to read information about or from each token. Most
significantly, this introduces the ability to read `#text` nodes in the
document.
What's new in the Tag Processor?
================================
- `next_token()` visits every distinct syntax token in a document.
- `get_token_type()` indicates what kind of token it is.
- `get_token_name()` returns something akin to `DOMNode.nodeName`.
- `get_modifiable_text()` returns the text associated with a token.
- `get_comment_type()` indicates why a token represents an HTML comment.
Example usage.
==============
{{{
<?php
function strip_all_tags( $html ) {
$text_content = '';
$processor = new WP_HTML_Tag_Processor( $html );
while ( $processor->next_token() ) {
if ( '#text' !== $processor->get_token_type() ) {
continue;
}
$text_content .= $processor->get_modifiable_text();
}
return $text_content;
}
}}}
What changes in the Tag Processor?
==================================
Previously, the Tag Processor would scan the opening and closing tag of
every HTML element separately. Now, however, there are special tags
which it only visits once, as if those elements were void tags without
a closer.
These are special tags because their content contains no other HTML or
markup, only non-HTML content.
- SCRIPT elements contain raw text which is isolated from the rest of
the HTML document and fed separately into a JavaScript engine. There
are complicated rules to avoid escaping the script context in the HTML.
The contents are left verbatim, and character references are not decoded.
- TEXTARA and TITLE elements contain plain text which is decoded
before display, e.g. transforming `&` into `&`. Any markup which
resembles tags is treated as verbatim text and not a tag.
- IFRAME, NOEMBED, NOFRAMES, STYLE, and XMP elements are similar to the
textarea and title elements, but no character references are decoded.
For example, `&` inside a STYLE element is passed to the CSS engine
as the literal string `&` and _not_ as `&`.
Because it's important not treat this inner content separately from the
elements containing it, the Tag Processor combines them when scanning
into a single match and makes their content available as modifiable
text (see below).
This means that the Tag Processor will no longer visit a closing tag for
any of these elements unless that tag is unexpected.
{{{
<title>There is only a single token in this line</title>
<title>There are two tokens in this line></title></title>
</title><title>There are still two tokens in this line></title>
}}}
What are tokens?
================
The term "token" here is a parsing term, which means a primitive unit in
HTML. There are only a few kinds of tokens in HTML:
- a tag has a name, attributes, and a closing or self-closing flag.
- a text node, or `#text` node contains plain text which is displayed
in a browser and which is decoded before display.
- a DOCTYPE declaration indicates how to parse the document.
- a comment is hidden from the display on a page but present in the HTML.
There are a few more kinds of tokens that the HTML Tag Processor will
recognize, some of which don't exist as concepts in HTML. These mostly
comprise XML syntax elements that aren't part of HTML (such as CDATA and
processing instructions) and invalid HTML syntax that transforms into
comments.
What is a funky comment?
========================
This patch treats a specific kind of invalid comment in a special way.
A closing tag with an invalid name is considered a "funky comment." In
the browser these become HTML comments just like any other, but their
syntax is convenient for representing a variety of bits of information
in a well-defined way and which cannot be nested or recursive, given
the parsing rules handling this invalid syntax.
- `</1>`
- `</%avatar_url>`
- `</{"wp_bit": {"type": "post-author"}}>`
- `</[post-author]>`
- `</__( 'Save Post' );>`
All of these examples become HTML comments in the browser. The content
inside the funky content is easily parsable, whereby the only rule is
that it starts at the `<` and continues until the nearest `>`. There
can be no funky comment inside another, because that would imply having
a `>` inside of one, which would actually terminate the first one.
What is modifiable text?
========================
Modifiable text is similar to the `innerText` property of a DOM node.
It represents the span of text for a given token which may be modified
without changing the structure of the HTML document or the token.
There is currently no mechanism to change the modifiable text, but this
is planned to arrive in a later patch.
Tags
====
Most tags have no modifiable text because they have child nodes where
text nodes are found. Only the special tags mentioned above have
modifiable text.
{{{
<div class="post">Another day in HTML</div>
└─ tag ──────────┘└─ text node ─────┘└────┴─ tag
}}}
{{{
<title>Is <img> > <image>?</title>
│ └ modifiable text ───┘ │ "Is <img> > <image>?"
└─ tag ─────────────────────────────┘
}}}
Text nodes
==========
Text nodes are entirely modifiable text.
{{{
This HTML document has no tags.
└─ modifiable text ───────────┘
}}}
Comments
========
The modifiable text inside a comment is the portion of the comment that
doesn't form its syntax. This applies for a number of invalid comments.
{{{
<!-- this is inside a comment -->
│ └─ modifiable text ──────┘ │
└─ comment token ───────────────┘
}}}
{{{
<!-->
This invalid comment has no modifiable text.
}}}
{{{
<? this is an invalid comment -->
│ └─ modifiable text ────────┘ │
└─ comment token ───────────────┘
}}}
{{{
<[CDATA[this is an invalid comment]]>
│ └─ modifiable text ───────┘ │
└─ comment token ───────────────────┘
}}}
Other token types also have modifiable text. Consult the code or tests
for further information.
Developed in https://github.com/WordPress/wordpress-develop/pull/5683
Discussed in https://core.trac.wordpress.org/ticket/60170
Follows [57575]
Props bernhard-reiter, dlh, dmsnell, jonsurrell, zieladam
Fixes#60170
Built from https://develop.svn.wordpress.org/trunk@57348
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Adds support for the following HTML elements to the HTML Processor:
- PARAM, SOURCE, TRACK
Previously these elements were not supported and the HTML Processor would bail when encountering them. Now, with this patch applied, it will proceed to parse an HTML document when encountering those tags.
Props jonsurrell, dmsnell
Fixes#60283
Built from https://develop.svn.wordpress.org/trunk@57326
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This patch adds newly supported elements to tests that should have been updated
in recent PRs, but which were merged without that. Those PRs removed failing
tests showing that the elements were unsupported, but did not add the elements
to the list of supported ones.
It also removes some elements from the special-exclusion list of unsupported IN
BODY elements. These did not present in failing tests because earlier
conditions in the switch structure caught the tags before hitting the default
block.
Finally it adds some missing elements to the list of void elements. These
elements are not listed as void in the HTML specification because they are
deprecated. However, they are treated as void for the sake of HTML
serialization and the parsing rules indicate that they behave as void elements,
so it's safe to list them within the HTML API as void.
Developed in WordPress/wordpress-develop#5913
Fixes#60307
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Adds support for the following HTML elements to the HTML Processor:
- PRE, LISTING
Previously, these elements were not supported and the HTML Processor would bail when encountering them. Now, with this patch applied, it will proceed to parse an HTML document when encountering those tags.
Developed in WordPress/wordpress-develop#5903
Props jonsurrell, dmsnell
Fixes#60283
Built from https://develop.svn.wordpress.org/trunk@57317
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Adds support for the following HTML elements to the HTML Processor:
- AREA, BR, EMBED, KEYGEN, WBR
- Only the opening BR tag is supported, as the invalid closer `</br>`
involves more complicated rules, to be implemented later.
Previously, these elements were not supported and the HTML Processor
would bail when encountering them. With this patch it will proceed to
parse an HTML document when encountering those tags as long as other
normal conditions don't cause it to bail (such as complicated format
reconstruction rules).
Props jonsurrell, dmsnell
Fixes#60283
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Adds support for the following HTML elements to the HTML Processor:
- HR
Previously, this element was not supported and the HTML Processor would bail when encountering
it. Now, with this patch, it will proceed to parse an HTML document when encountering one.
Developed in WordPress/wordpress-develop#5897
Props jonsurrell, dmsnell
Fixes#60283
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Adds support for the following HTML elements to the HTML Processor:
- LI, OL, UL.
- DD, DL, DT.
Previously, these elements were not supported and the HTML Processor would bail when encountering them.
With this patch it will proceed to parse an HTML document when encountering those tags as long as other normal conditions don't cause it to bail (such as complicated format reconstruction).
Props audrasjb, jonsurrell, bernhard-reiter.
Fixes#60215.
Built from https://develop.svn.wordpress.org/trunk@57264
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The HTML API HTML processor does not yet support all tags. Many tags (e.g. list elements) have some complicated rules in the [https://html.spec.whatwg.org/#parsing-main-inbody "in body" insertion mode].
Implementing these special rules is blocking the implementation for a catch-all rule for "any other tag" because we need to prevent special rules from being handled by the catch-all.
Any other start tag
Reconstruct the active formatting elements, if any.
Insert an HTML element for the token.
…
This change ensures the HTML Processor fails when handling special tags. This is the same as existing behavior, but will allow us to implement the catch-all "any other tag" handling without unintentionally handling special elements.
Additionally, we add tests that assert the special elements are unhandled. As these tags are implemented, this should help to ensure they're removed from the unsupported tag list.
Props jonsurrell, dmsnell.
Fixes#60092.
Built from https://develop.svn.wordpress.org/trunk@57248
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Currently the Tag Processor assumes that an input document is a ''full'' HTML document. Because of this, if there's lingering content after the last tag match it will treat that content as plaintext and skip over it. This is fine for the Tag Processor because if there is lingering content that isn't a valid tag then there's nothing for `next_tag()` to match.
However, in order to support a number of feature expansions it is important to recognize that the remaining content ''may'' involve partial syntax elements, such as incomplete tags, attributes, or comments.
In this patch we're adding a mode inside the Tag Processor which will flip when we start parsing HTML syntax but the document finishes before the token does. This will provide the ability to:
- extend the input document,
- avoid misinterpreting syntax as text, and
- guess if we have a complete document, know if we have an incomplete document.
In the process of building this patch a few fixes were identified and fixed in the Tag Processor, namely in the handling of incomplete syntax elements.
Props dmsnell, jonsurrell.
Fixes#60122, #60108.
Built from https://develop.svn.wordpress.org/trunk@57211
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Previously these have been unsupported, but in this patch, support is added for the tags so that the HTML Processor can process documents containing them.
There was a design discussion about introducing a constant to communicate "any of the H1 - H6 elements" but this posed a number of challenges that don't need to be answered in this patch. For the time being, because the HTML specification treats H1 - H6 specially as a single kind of element, the HTML Processor uses an internal hard-coded string to indicate this. By using a hard-coded string it's possible to avoid introducing a class constant which cannot be made private due to PHP's class design. In the future, this will probably appear as a special constant in a new constant-containing class.
Props dmsnell, jonsurrell.
Fixes#60060.
Built from https://develop.svn.wordpress.org/trunk@57186
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Updates the internal representation of the text span coordinates. The mixture of (offset, length) and (start, end) coordinates becomes confusing, this commit replaces it with a (offset, length) pair. There should be no functional or behavioral changes in this patch. For the internal helper classes this patch introduces breaking changes, but those classes are marked private and should not be used outside of the HTML API itself.
Props dmsnell.
Fixes#59993.
Built from https://develop.svn.wordpress.org/trunk@57179
git-svn-id: http://core.svn.wordpress.org/trunk@56690 1a063a9b-81f0-0310-95a4-ce76da25c4cd
The example code in the PHPDoc comment for the HTML Tag Processor class
previously showed calling `next_tag()` with an array containing a `class`
key, which should have been `class_name`. This patch fixes this by using
the appropriate `class_name` key.
Props dmsnell, gaambo, crstauf, atachibana, audrasjb, krupalpanchal.
Fixes#59891.
Built from https://develop.svn.wordpress.org/trunk@57116
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There are a handful of elements which behave similarly and are generically container elements. These are the following elements:
ADDRESS, ARTICLE, ASIDE, BLOCKQUOTE, CENTER, DETAILS, DIALOG, DIR,
DL, DIV, FIELDSET, FIGCAPTION, FIGURE, FOOTER, HEADER, HGROUP, MAIN,
MENU, NAV, SEARCH, SECTION, SUMMARY
This patch adds support to the HTML Processor for handling these elements. They do not require any additional logic in the rest of the class, and carry no specific semantic rules for parsing beyond what is listed in their group in the IN BODY section of the HTML5 specification.
Props dmsnell.
Fixes#59914.
Built from https://develop.svn.wordpress.org/trunk@57115
git-svn-id: http://core.svn.wordpress.org/trunk@56626 1a063a9b-81f0-0310-95a4-ce76da25c4cd
When applying updates to HTML, one step was left out in [56941] which updated the position of the end of the current tag. This made it possible to create bookmarks with null or earlier end positions than their start position. This in turn broke the Directive Processor in Gutenberg during the backport of changes from Core into Gutenberg.
In this commit, after applying updates, the HTML document is now scanned fully to the end of the current tag, updating the internal pointer to its end, so that nothing else will be broken or misaligned.
Follow-up to [56941].
Props dmsnell.
Fixes#59643.
Built from https://develop.svn.wordpress.org/trunk@56953
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After modifying tags in the HTML API, the Tag Processor backs up to before the tag being modified and then re-parses its attributes. This saves on the code complexity involved in applying updates, which have already been transformed to “lexical updates” by the time they are applied.
In order to do that, `::get_updated_html()` called `::next_tag()` to reuse its logic. However, as a public method, subclasses may change the behavior of that method, and the HTML Processor does just this. It maintains an HTML stack of open elements and when the Tag Processor calls this method to re-scan a tag and its attributes, it leads to a broken stack.
This commit replaces the call to `::next_tag()` with a more appropriate reapplication of its internal parsing logic to rescan the tag name and its attributes. Given the limited nature of what's occurring in `::get_updated_html()`, this should bring with it certain guarantees that no HTML structure is being changed (that structure will only be changed by subclasses like the HTML Processor).
Follow-up to [56274], [56702].
Props dmsnell, zieladam, nicolefurlan.
Fixes#59607.
Built from https://develop.svn.wordpress.org/trunk@56941
git-svn-id: http://core.svn.wordpress.org/trunk@56452 1a063a9b-81f0-0310-95a4-ce76da25c4cd
This patch adds two new public methods to the HTML Tag Processor:
- `has_class()` indicates if a matched tag contains a given CSS class name.
- `class_list()` returns a generator to iterate over all the class names in a matched tag.
Included in this patch is a refactoring of the internal logic when matching
a tag to reuse the new `has_class()` function. Previously it was relying on
optimized code in the `matches()` function which performed byte-for-byte
class name comparison. With the change in this patch it will perform class
name matching on the decoded value, which might differ if a class attribute
contains character references.
These methods may be useful for running more complicated queries based
on the presence or absence of CSS class names. The use of these methods
avoids the need to manually decode the class attribute as reported by
`$process->get_attribute( 'class' )`.
Props dmsnell.
Fixes#59209.
Built from https://develop.svn.wordpress.org/trunk@56703
git-svn-id: http://core.svn.wordpress.org/trunk@56215 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Inside a `next_tag()` loop it can be challenging to use breadcrumbs because they are only exposed inside the call to `next_tag()` via the `$query` arg.
In this patch a new method, `matches_breadcrumbs()`, is exposed which allows for querying within the `next_tag()` loop for more complicated queries.
This method exposes a wildcard `*` operator to allow matching ''any HTML tag'' that the currently-matched tag is a child or descendant of.
Props dmsnell, westonruter, mukesh27.
Fixes#59400.
Built from https://develop.svn.wordpress.org/trunk@56702
git-svn-id: http://core.svn.wordpress.org/trunk@56214 1a063a9b-81f0-0310-95a4-ce76da25c4cd
When encountering an HTML tag with duplicate copies of an attribute the tag processor ignores the duplicate values, according to the specification. However, when removing an attribute it must remove all copies of that attribute lest one of the duplicates becomes the primary and it appears as if no attributes were removed.
In this patch we're adding tests that will be used to ensure that all attribute copies are removed from a tag when one is request to be removed.
**Before**
{{{#!php
<?php
$p = new WP_HTML_Tag_Processor( '<br id=one id="two" id='three' id>' );
$p->next_tag();
$p->remove_attribute( 'id' );
$p->get_updated_html();
// <br id="two" id='three' id>
}}}
**After**
{{{#!php
<?php
$p = new WP_HTML_Tag_Processor( '<br id=one id="two" id='three' id>' );
$p->next_tag();
$p->remove_attribute( 'id' );
$p->get_updated_html();
// <br>
}}}
Previously we have been overlooking duplicate attributes since they don't have an impact on what parses into the DOM. However, as one unit test affirmed (asserting the presence of the bug in the tag processor) when removing an attribute where duplicates exist this meant we ended up changing the value of an attribute instead of removing it.
In this patch we're tracking the text spans of the parsed duplicate attributes so that ''if'' we attempt to remove them then we'll have the appropriate information necessary to do so. When an attribute isn't removed we'll simply forget about the tracked duplicates. This involves some overhead for normal operation ''when'' in fact there are duplicate attributes on a tag, but that overhead is minimal in the form of integer pairs of indices for each duplicated attribute.
Props dmsnell, zieladam.
Fixes#58119.
Built from https://develop.svn.wordpress.org/trunk@56684
git-svn-id: http://core.svn.wordpress.org/trunk@56196 1a063a9b-81f0-0310-95a4-ce76da25c4cd
This patch updates documentation and an internal variable name within the
HTML Processor class so that they are more helpful and complete to a reader.
There should be no functional or visual changes in this patch.
Props dmsnell, mukesh27.
Fixes#59267.
Built from https://develop.svn.wordpress.org/trunk@56565
git-svn-id: http://core.svn.wordpress.org/trunk@56077 1a063a9b-81f0-0310-95a4-ce76da25c4cd
When encountering elements that imply switching into the RAWTEXT parsing state,
the Tag Processor should skip processing until exiting the RAWTEXT state.
In this patch the Tag Processor does just that, except for the case of the
deprecated XMP element which implies further and more complicated rules.
There's an implicit assumption that the SCRIPT ENABLED flag in HTML parsing
is enabled so that the contents of NOSCRIPT can be skipped. Otherwise, it would
be required to parse the contents of that tag.
Props dmsnell.
Fixes#59292.
Built from https://develop.svn.wordpress.org/trunk@56563
git-svn-id: http://core.svn.wordpress.org/trunk@56075 1a063a9b-81f0-0310-95a4-ce76da25c4cd
The `$current_token` reference has been stored in the HTML Processor itself, but I suggested to move it into the externalized state so that it can be stored and replaced.
In this patch the reference is moved to that state variable and it should become more possible to save and load state, to resume execution after pausing.
Props dmsnell.
Fixes#59268.
Built from https://develop.svn.wordpress.org/trunk@56558
git-svn-id: http://core.svn.wordpress.org/trunk@56070 1a063a9b-81f0-0310-95a4-ce76da25c4cd
It was a design goal of the HTML Processor to abort processing its input document when encountering unsupported markup. Unfortunately there was no test for this and so-far, the HTML Processor has paused, but continued processing in these situations.
In this patch a new test ensures that the HTML Processor stops and refuses to move forward after encountering any unsupported markup. It also ensures that it doesn't report any current tag names since unsupported markup could imply that the read tag name is different than the parsed tag name.
Props dmsnell.
Fixes#59167.
Built from https://develop.svn.wordpress.org/trunk@56493
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This patch adds support to process the BUTTON element. This requires adding some additional semantic rules to handle situations where a BUTTON element is already in scope.
Also included is a fixup to enforce that `WP_HTML_Processor::next_tag()` never returns for a tag closer. This is useful with the Tag Processor, but not for the HTML Processor. There were tests relying on this behavior to assert that internal processes were working as they should, but those tests have been updated to use the semi-private `step()` function, which does stop on tag closers.
This patch is one in a series of changes to expand support within the HTML API, moving gradually to allow for more focused changes that are easier to review and test. The HTML Processor is a work in progress with a certain set of features slated to be ready and tested by 6.4.0, but it will only contain partial support of the HTML5 specification even after that. Whenever it cannot positively recognize and process its input it bails, and certain function stubs and logical stubs exist to structure future expansions of support.
Props dmsnell.
Fixes#58961.
Built from https://develop.svn.wordpress.org/trunk@56380
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Adjust the code style according to the rules that the linting process in Gutenberg requires.
There are only a couple code changes that should have no effect on the runtime:
- A missing check to verify that only `UTF-8` is supported has been added (brought up because it was identified as an undefined variable).
- A few `return false;` statements have been added to avoid having the linter complain that functions don't return a value despite indicating they return `bool`. The functions are stubs for coming support and currently `throw`, so the `return` statements are unreachable.
Props dmsnell, costdev, davidbaumwald, peterwilsoncc, SergeyBiryukov.
Fixes#58918.
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In this patch we're introducing support for the SPAN element, which is the first
in the class of "any other tag" in the "in body" insertion mode.
This patch introduces the mechanisms required to handle that class of tags but
only introduces SPAN to keep the change focused. With the tests and mechanisms
in place it will be possible to follow-up and add another limited set of tags.
It's important that this not use the default catch-all in the switch handling
`step_in_body` because that would catch tags that have specific rules in previous
case statements that aren't yet added. For example, we don't want to treat the
`TABLE` element as "any other tag".
Props dmsnell.
Fixes#58907.
Built from https://develop.svn.wordpress.org/trunk@56331
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This patch introduces the //first// of //many// iterations on the evolution of the HTML API, the HTML Processor, which is built in order to understand HTML structure including nesting, misnesting, and complicated semantic rules.
In the first iteration, the HTML Processor is arbitrarily limited to a minimal subset of functionality so that we can review it, ship it, test it, and collect feedback before moving forward. This means that this patch is more or less an extension to the Tag Processor query language, providing the ability not only to scan for a tag of a given name, but also to find an HTML element in a specific nesting path.
The HTML Processor also aborts any time it encounters:
- a tag that isn't a `P`, `DIV`, `FIGURE`, `FIGCAPTION`, `IMG`, `STRONG`, `B`, `EM`, `I`, `A`, `BIG`, `CODE`, `FONT`, `SMALL`, `STRIKE`, `TT`, or `U` tag. this limit exists because many HTML elements require specific rules and we are trying to limit the number of rules introduced at once. this work is targeted at existing work in places like the image block.
- certain misnesting constructs that evoke complicated resolution inside the HTML spec. where possible and where simple to do reliably, certain parse errors are handled. in most cases the HTML Processor aborts.
The structure of the HTML Processor is established in this patch. Further spec-compliance comes through filling out //more of the same// kind and nature of code as is found in this patch. Certain critical HTML algorithms are partially supported, and where support requires more than is present, the HTML Processor acknowledges this and refuses to operate.
In this patch are explorations for how to verify that new HTML support is fully added (instead of allowing for partial updates that leave some code paths non-compliant). Performance is hard to measure since support is so limited at the current time, but it should generally follow the performance of the Tag Processor somewhat close as the overhead is minimized as much as practical.
Props dmsnell, zieladam, costdev.
Fixes#58517.
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This moves a reference link in `::get_attribute_names_with_prefix()` below the code example, so that it is correctly displayed in the Developer Resources.
Includes updating some other `@see` tags for consistency as per the documentation standards.
Additionally, the example code for `WP_HTML_Tag_Processor::get_tag()` is updated to show lowercase tag names in the input HTML, so that it does not convey the wrong impression that the uppercase output from `::get_tag()` depends on the case of the input HTML.
Follow-up to [55203].
Props dmsnell, johnbillion, audrasjb, SergeyBiryukov.
Fixes#58254.
Built from https://develop.svn.wordpress.org/trunk@55724
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In [55718] the Unicode replacement character was mistakenly removed. The purpose of including the character was to communicate what it looks like and why the Tag Processor won't insert it into the document.
This changeset brings the character back and adds a small clue to fix the confusion that may lead to its removal.
Follow-up to [55718].
Props dmsnell.
Fixes#58256
See #57840.
Built from https://develop.svn.wordpress.org/trunk@55723
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A bug was discovered where where the parser wasn't returning to the
start of the affected tag after making some updates.
In few words, the Tag Processor has not been treating its own internal
pointer `bytes_already_parsed` the same way it treats its bookmarks.
That is, when updates are applied to the input document and then
`get_updated_html()` is called, the internal pointer transfers to
the newly-updated content as if no updates had been applied since
the previous call to `get_updated_html()`.
In this patch we're creating a new "shift accumulator" to account for
all of the updates that accrue before calling `get_updated_html()`.
This accumulated shift will be applied when swapping the input document
with the output buffer, which should result in the pointer pointing to
the same logical spot in the document it did before the udpate.
In effect this patch adds a single workaround for treating the
internal pointer like a bookmark, plus a temporary pointer which points
to the beginning of the current tag when calling `get_updated_html()`.
This will preserve the assumption that updating a document doesn't
move that pointer, or shift which tag is currently matched.
Props dmsnell, zieladam.
Fixes#58179.
Built from https://develop.svn.wordpress.org/trunk@55706
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- Comments created by means of a tag closer with an invalid tag name, e.g. `</3>`.
- Comments closed with the invalid `--!>` closer. (Comments should be closed by `-->` but if the `!` appears it will also close it, in error.)
- Empty tag name elements, which are technically skipped over and aren't comments, e.g. `</>`.
Props dmsnell, costdev.
Fixes#58007.
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