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Add more complete CSS selector parsing, add failing test case for nes…
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…ted selector
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@dmsnell
dmsnell committed Dec 13, 2022
1 parent 175eb1f commit 89a3b32
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Showing 2 changed files with 262 additions and 82 deletions.
185 changes: 119 additions & 66 deletions lib/experimental/html/class-wp-html-attribute-sourcer.php
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Original file line number Diff line number Diff line change
Expand Up @@ -52,6 +52,18 @@ function array_is_list( $array ) {
}
}

class Selector {
public $element = null;
public $class = null;
public $hash = null;
public $has_attribute = null;
public $then = null;
}

class ParseResult {
public $last_index;
public $selector = null;
}

class WP_HTML_Attribute_Sourcer {
/**
Expand Down Expand Up @@ -121,22 +133,32 @@ public static function select( $selectors, $html ) {

while ( $tags->next_tag() ) {
foreach ( $selectors as $s ) {
if ( ! empty( $s['has_attribute'] ) && null === $tags->get_attribute( $s['has_attribute'] ) ) {
if ( ! empty( $s['tag_name'] ) && strtoupper( $s['tag_name'] ) !== $tags->get_tag() ) {
continue;
}

if ( 'element' === $s['type'] && $tags->get_tag() === strtoupper( $s['identifier'] ) ) {
return $tags;
if ( ! empty( $s['class_names'] ) ) {
$classes = $tags->get_attribute( 'class' );
if ( null === $classes ) {
continue;
}

foreach ( $s['class_names'] as $class_name ) {
if ( ! preg_match( "~\b{$class_name}\b~", $classes ) ) {
continue 2;
}
}
}

// @TODO: $tags->has_class() would be _really_ handy here.
if ( 'class' === $s['type'] && preg_match( "~\b{$s['identifier']}\b~", $tags->get_attribute( 'class' ) ) ) {
return $tags;
if ( isset( $s['hash'] ) && $s['identifier'] !== $tags->get_attribute( 'id' ) ) {
continue;
}

if ( 'hash' === $s['type'] && $s['identifier'] === $tags->get_attribute( 'id' ) ) {
return $tags;
if ( isset( $s['has_attribute'] ) && null === $tags->get_attribute( $s['has_attribute'] ) ) {
continue;
}

return $tags;
}
}

Expand All @@ -161,47 +183,108 @@ public static function parse_definition( $definition ) {
return 'inner-html';
}

$selector = self::parse_selector( $definition['selector'] );
if ( null === $selector ) {
$selectors = self::parse_full_selector( $definition['selector'] );
if ( null === $selectors ) {
return 'unsupported';
}

if ( 'html' === $source ) {
return array( 'type' => 'html', 'selector' => $selector );
return array( 'type' => 'html', 'selector' => $selectors );
}

$attribute = self::parse_attribute( $definition['attribute'] );
if ( null === $attribute ) {
return null;
}

return array( 'type' => 'attribute', 'selector' => $selector, 'attribute' => $attribute );
return array( 'type' => 'attribute', 'selector' => $selectors, 'attribute' => $attribute );
}

public static function parse_selector( $s, $at = 0 ) {
$budget = 1000;
public static function parse_full_selector( $s ) {
$selectors = [];
$at = 0;

while ( $at < strlen( $s ) && $budget-- > 0 ) {
$type = 'element';
$attribute = null;
while ( $at < strlen( $s ) ) {
$at += strspn( $s, " \f\n\r\t", $at );

list( $selector, $next_at ) = self::parse_selector( $s, $at );
if ( null === $selector ) {
return null;
}

$selectors[] = $selector;
$at = $next_at;

if ( $at < strlen( $s ) && ',' !== $s[ $at ] ) {
return null;
}
$at++;
}

return $selectors;
}

public static function parse_selector( $s, $at = 0, $selector = [] ) {
$is_first = true;

while ( $at < strlen( $s ) && ',' !== $s[ $at ] ) {
/*
* Descendant combinators are harder to discover because we
* always have to skip whitespace, but that whitespace could
* be the combinator if we don't approach anything else first.
*/
$ws_length = strspn( $s, " \f\n\r\t", $at );
$at += $ws_length;

if ( !$is_first && $ws_length > 0 && 0 === strspn( $s[ $at ], '>+~' ) ) {
$at--;
$s[ $at ] = ' ';
}
$is_first = false;

switch ( $s[ $at ] ) {
case '>':
case '+':
// no support for adjacent sibling combinator
return null;
case '~':
case ' ':
$combinator = $s[ $at ];
$at++;
$at += strspn( $s, " \f\n\r\t", $at );
$inner = self::parse_selector( $s, $at );
if ( null === $inner ) {
return null;
}
list( $inner_selector, $next_at ) = $inner;
$inner_selector['combinator'] = $combinator;
$selector['then'] = $inner_selector;
$at = $next_at;
break;

case '>':
// no support for child combinator
return null;
case '.':
$at++;
$class_name = self::parse_css_identifier( $s, $at );
if ( null === $class_name ) {
return null;
}

case '~':
// no support for general sibling combinator
return null;
if ( ! isset( $selector['class_names'] ) ) {
$selector['class_names'] = array();
}
$selector['class_names'][] = $class_name;
$at += strlen( $class_name );
break;

case ' ':
// no support for descendant combinator
return null;
case '#':
$at++;
// @TODO: Hashes don't have to start with `nmstart` so this might reject valid hash names.
$element_id = self::parse_css_identifier( $s, $at );
if ( null === $element_id ) {
return null;
}

$selector['hash'] = $element_id;
$at += strlen( $element_id );
break;

case '[':
/*
Expand All @@ -218,51 +301,21 @@ public static function parse_selector( $s, $at = 0 ) {
$attribute = substr( $s, $at, $inside_length );
$at += $inside_length + 1;

$selector = array_pop( $selectors );
$selector['has_attribute'] = $attribute;
$selectors[] = $selector;

continue 2;

case ',':
$at++;
$at += strspn( $s, " \t\f\r\n", $at );
continue 2;

case ':':
// no support for pseudo-selectors
return null;

case '#':
$type = 'hash';
$at++;
break;

case '.':
$type = 'class';
$at++;
break;
}

// @TODO: Hashes don't have to start with `nmstart` so this might reject valid hash names.
$identifier = self::parse_css_identifier( $s, $at );
if ( null === $identifier ) {
return null;
}
default:
$tag_name = self::parse_css_identifier( $s, $at );
if ( null === $tag_name ) {
return null;
}

$selector = array( 'type' => $type, 'identifier' => $identifier );
if ( null !== $attribute ) {
$selector['has_attribute'] = $selector;
$selector['tag_name'] = $tag_name;
$at += strlen( $tag_name );
}

$selectors[] = $selector;

$at += strlen( $identifier );
}

return $at === strlen( $s )
? $selectors
: null;
return [ $selector, $at ];
}

/**
Expand Down
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