Changeset 45929 for trunk/src/wp-includes/formatting.php

Timestamp:

09/02/2019 10:24:18 AM (6 years ago)

Author:

flixos90

Message:

Formatting: Improve accuracy of force_balance_tags() and add support for custom element tags.

This changeset includes a major iteration on the regular expression used to balance tags, with comprehensive test coverage to ensure that all scenarios are supported or unsupported as expected.

Props dmsnell, westonruter, birgire.
Fixes #47014.

File:

• trunk/src/wp-includes/formatting.php (modified) (6 diffs)

trunk/src/wp-includes/formatting.php

@@ -2430 +2430 @@
  */
 function balanceTags( $text, $force = false ) {  // phpcs:ignore WordPress.NamingConventions.ValidFunctionName.FunctionNameInvalid
-    if ( $force || get_option( 'use_balanceTags' ) == 1 ) {
+    if ( $force || (int) get_option( 'use_balanceTags' ) === 1 ) {
         return force_balance_tags( $text );
     } else {
@@ -2441 +2441 @@
  *
  * @since 2.0.4
+ * @since 5.3.0 Improve accuracy and add support for custom element tags.
  *
  * @author Leonard Lin <leonard@acm.org>
@@ -2470 +2471 @@
     $text = preg_replace( '#<([0-9]{1})#', '&lt;$1', $text );
 
-    while ( preg_match( '/<(\/?[\w:]*)\s*([^>]*)>/', $text, $regex ) ) {
+    /**
+     * Matches supported tags.
+     *
+     * To get the pattern as a string without the comments paste into a PHP
+     * REPL like `php -a`.
+     *
+     * @see https://html.spec.whatwg.org/#elements-2
+     * @see https://w3c.github.io/webcomponents/spec/custom/#valid-custom-element-name
+     *
+     * @example
+     * ~# php -a
+     * php > $s = [paste copied contents of expression below including parentheses];
+     * php > echo $s;
+     */
+    $tag_pattern = (
+        '#<' . // Start with an opening bracket.
+        '(/?)' . // Group 1 - If it's a closing tag it'll have a leading slash.
+        '(' . // Group 2 - Tag name.
+            // Custom element tags have more lenient rules than HTML tag names.
+            '(?:[a-z](?:[a-z0-9._]*)-(?:[a-z0-9._-]+)+)' .
+                '|' .
+            // Traditional tag rules approximate HTML tag names.
+            '(?:[\w:]+)' .
+        ')' .
+        '(?:' .
+            // We either immediately close the tag with its '>' and have nothing here.
+            '\s*' .
+            '(/?)' . // Group 3 - "attributes" for empty tag.
+                '|' .
+            // Or we must start with space characters to separate the tag name from the attributes (or whitespace).
+            '(\s+)' . // Group 4 - Pre-attribute whitespace.
+            '([^>]*)' . // Group 5 - Attributes.
+        ')' .
+        '>#' // End with a closing bracket.
+    );
+
+    while ( preg_match( $tag_pattern, $text, $regex ) ) {
+        $full_match        = $regex[0];
+        $has_leading_slash = ! empty( $regex[1] );
+        $tag_name          = $regex[2];
+        $tag               = strtolower( $tag_name );
+        $is_single_tag     = in_array( $tag, $single_tags, true );
+        $pre_attribute_ws  = isset( $regex[4] ) ? $regex[4] : '';
+        $attributes        = trim( isset( $regex[5] ) ? $regex[5] : $regex[3] );
+        $has_self_closer   = '/' === substr( $attributes, -1 );
+
         $newtext .= $tagqueue;
 
-        $i = strpos( $text, $regex[0] );
-        $l = strlen( $regex[0] );
-
-        // clear the shifter
+        $i = strpos( $text, $full_match );
+        $l = strlen( $full_match );
+
+        // Clear the shifter.
         $tagqueue = '';
-        // Pop or Push
-        if ( isset( $regex[1][0] ) && '/' == $regex[1][0] ) { // End Tag
-            $tag = strtolower( substr( $regex[1], 1 ) );
-            // if too many closing tags
+        if ( $has_leading_slash ) { // End Tag.
+            // If too many closing tags.
             if ( $stacksize <= 0 ) {
                 $tag = '';
-                // or close to be safe $tag = '/' . $tag;
-
-                // if stacktop value = tag close value then pop
-            } elseif ( $tagstack[ $stacksize - 1 ] == $tag ) { // found closing tag
-                $tag = '</' . $tag . '>'; // Close Tag
-                // Pop
+                // Or close to be safe $tag = '/' . $tag.
+
+                // If stacktop value = tag close value, then pop.
+            } elseif ( $tagstack[ $stacksize - 1 ] === $tag ) { // Found closing tag.
+                $tag = '</' . $tag . '>'; // Close Tag.
                 array_pop( $tagstack );
                 $stacksize--;
-            } else { // closing tag not at top, search for it
+            } else { // Closing tag not at top, search for it.
                 for ( $j = $stacksize - 1; $j >= 0; $j-- ) {
-                    if ( $tagstack[ $j ] == $tag ) {
-                        // add tag to tagqueue
+                    if ( $tagstack[ $j ] === $tag ) {
+                        // Add tag to tagqueue.
                         for ( $k = $stacksize - 1; $k >= $j; $k-- ) {
                             $tagqueue .= '</' . array_pop( $tagstack ) . '>';
@@ -2505 +2548 @@
                 $tag = '';
             }
-        } else { // Begin Tag
-            $tag = strtolower( $regex[1] );
-
-            // Tag Cleaning
-
-            // If it's an empty tag "< >", do nothing
-            if ( '' == $tag ) {
-                // do nothing
-            } elseif ( substr( $regex[2], -1 ) == '/' ) { // ElseIf it presents itself as a self-closing tag...
+        } else { // Begin Tag.
+            if ( $has_self_closer ) { // If it presents itself as a self-closing tag...
                 // ...but it isn't a known single-entity self-closing tag, then don't let it be treated as such and
                 // immediately close it with a closing tag (the tag will encapsulate no text as a result)
-                if ( ! in_array( $tag, $single_tags ) ) {
-                    $regex[2] = trim( substr( $regex[2], 0, -1 ) ) . "></$tag";
+                if ( ! $is_single_tag ) {
+                    $attributes = trim( substr( $attributes, 0, -1 ) ) . "></$tag";
                 }
-            } elseif ( in_array( $tag, $single_tags ) ) { // ElseIf it's a known single-entity tag but it doesn't close itself, do so
-                $regex[2] .= '/';
-            } else { // Else it's not a single-entity tag
-                // If the top of the stack is the same as the tag we want to push, close previous tag
-                if ( $stacksize > 0 && ! in_array( $tag, $nestable_tags ) && $tagstack[ $stacksize - 1 ] == $tag ) {
+            } elseif ( $is_single_tag ) { // ElseIf it's a known single-entity tag but it doesn't close itself, do so
+                $pre_attribute_ws = ' ';
+                $attributes      .= '/';
+            } else { // It's not a single-entity tag.
+                // If the top of the stack is the same as the tag we want to push, close previous tag.
+                if ( $stacksize > 0 && ! in_array( $tag, $nestable_tags, true ) && $tagstack[ $stacksize - 1 ] === $tag ) {
                     $tagqueue = '</' . array_pop( $tagstack ) . '>';
                     $stacksize--;
@@ -2530 +2567 @@
             }
 
-            // Attributes
-            $attributes = $regex[2];
-            if ( ! empty( $attributes ) && $attributes[0] != '>' ) {
-                $attributes = ' ' . $attributes;
+            // Attributes.
+            if ( $has_self_closer && $is_single_tag ) {
+                // We need some space - avoid <br/> and prefer <br />.
+                $pre_attribute_ws = ' ';
             }
 
-            $tag = '<' . $tag . $attributes . '>';
-            //If already queuing a close tag, then put this tag on, too
+            $tag = '<' . $tag . $pre_attribute_ws . $attributes . '>';
+            // If already queuing a close tag, then put this tag on too.
             if ( ! empty( $tagqueue ) ) {
                 $tagqueue .= $tag;
@@ -2547 +2584 @@
     }
 
-    // Clear Tag Queue
+    // Clear Tag Queue.
     $newtext .= $tagqueue;
 
-    // Add Remaining text
+    // Add remaining text.
     $newtext .= $text;
 
-    // Empty Stack
     while ( $x = array_pop( $tagstack ) ) {
-        $newtext .= '</' . $x . '>'; // Add remaining tags to close
-    }
-
-    // WP fix for the bug with HTML comments
+        $newtext .= '</' . $x . '>'; // Add remaining tags to close.
+    }
+
+    // WP fix for the bug with HTML comments.
     $newtext = str_replace( '< !--', '<!--', $newtext );
     $newtext = str_replace( '<    !--', '< !--', $newtext );