Changeset 56703 for trunk/src/wp-includes/html-api/class-wp-html-tag-processor.php

Timestamp:

09/26/2023 09:15:21 AM (3 years ago)

Author:

Bernhard Reiter

Message:

HTML API: Add class name utilities has_class() and class_list().

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.

File:

• trunk/src/wp-includes/html-api/class-wp-html-tag-processor.php (modified) (2 diffs)

trunk/src/wp-includes/html-api/class-wp-html-tag-processor.php

@@ -624 +624 @@
 
         return true;
+    }
+
+
+    /**
+     * Generator for a foreach loop to step through each class name for the matched tag.
+     *
+     * This generator function is designed to be used inside a "foreach" loop.
+     *
+     * Example:
+     *
+     *     $p = new WP_HTML_Tag_Processor( "<div class='free &lt;egg&lt;\tlang-en'>" );
+     *     $p->next_tag();
+     *     foreach ( $p->class_list() as $class_name ) {
+     *         echo "{$class_name} ";
+     *     }
+     *     // Outputs: "free <egg> lang-en "
+     *
+     * @since 6.4.0
+     */
+    public function class_list() {
+        /** @var string $class contains the string value of the class attribute, with character references decoded. */
+        $class = $this->get_attribute( 'class' );
+
+        if ( ! is_string( $class ) ) {
+            return;
+        }
+
+        $seen = array();
+
+        $at = 0;
+        while ( $at < strlen( $class ) ) {
+            // Skip past any initial boundary characters.
+            $at += strspn( $class, " \t\f\r\n", $at );
+            if ( $at >= strlen( $class ) ) {
+                return;
+            }
+
+            // Find the byte length until the next boundary.
+            $length = strcspn( $class, " \t\f\r\n", $at );
+            if ( 0 === $length ) {
+                return;
+            }
+
+            /*
+             * CSS class names are case-insensitive in the ASCII range.
+             *
+             * @see https://www.w3.org/TR/CSS2/syndata.html#x1
+             */
+            $name = strtolower( substr( $class, $at, $length ) );
+            $at  += $length;
+
+            /*
+             * It's expected that the number of class names for a given tag is relatively small.
+             * Given this, it is probably faster overall to scan an array for a value rather
+             * than to use the class name as a key and check if it's a key of $seen.
+             */
+            if ( in_array( $name, $seen, true ) ) {
+                continue;
+            }
+
+            $seen[] = $name;
+            yield $name;
+        }
+    }
+
+
+    /**
+     * Returns if a matched tag contains the given ASCII case-insensitive class name.
+     *
+     * @since 6.4.0
+     *
+     * @param string $wanted_class Look for this CSS class name, ASCII case-insensitive.
+     * @return bool|null Whether the matched tag contains the given class name, or null if not matched.
+     */
+    public function has_class( $wanted_class ) {
+        if ( ! $this->tag_name_starts_at ) {
+            return null;
+        }
+
+        $wanted_class = strtolower( $wanted_class );
+
+        foreach ( $this->class_list() as $class_name ) {
+            if ( $class_name === $wanted_class ) {
+                return true;
+            }
+        }
+
+        return false;
     }
 
@@ -2348 +2436 @@
         }
 
-        $needs_class_name = null !== $this->sought_class_name;
-
-        if ( $needs_class_name && ! isset( $this->attributes['class'] ) ) {
+        if ( null !== $this->sought_class_name && ! $this->has_class( $this->sought_class_name ) ) {
             return false;
         }
 
-        /*
-         * Match byte-for-byte (case-sensitive and encoding-form-sensitive) on the class name.
-         *
-         * This will overlook certain classes that exist in other lexical variations
-         * than was supplied to the search query, but requires more complicated searching.
-         */
-        if ( $needs_class_name ) {
-            $class_start = $this->attributes['class']->value_starts_at;
-            $class_end   = $class_start + $this->attributes['class']->value_length;
-            $class_at    = $class_start;
-
-            /*
-             * Ensure that boundaries surround the class name to avoid matching on
-             * substrings of a longer name. For example, the sequence "not-odd"
-             * should not match for the class "odd" even though "odd" is found
-             * within the class attribute text.
-             *
-             * See https://html.spec.whatwg.org/#attributes-3
-             * See https://html.spec.whatwg.org/#space-separated-tokens
-             */
-            while (
-                // phpcs:ignore WordPress.CodeAnalysis.AssignmentInCondition.FoundInWhileCondition
-                false !== ( $class_at = strpos( $this->html, $this->sought_class_name, $class_at ) ) &&
-                $class_at < $class_end
-            ) {
-                /*
-                 * Verify this class starts at a boundary.
-                 */
-                if ( $class_at > $class_start ) {
-                    $character = $this->html[ $class_at - 1 ];
-
-                    if ( ' ' !== $character && "\t" !== $character && "\f" !== $character && "\r" !== $character && "\n" !== $character ) {
-                        $class_at += strlen( $this->sought_class_name );
-                        continue;
-                    }
-                }
-
-                /*
-                 * Verify this class ends at a boundary as well.
-                 */
-                if ( $class_at + strlen( $this->sought_class_name ) < $class_end ) {
-                    $character = $this->html[ $class_at + strlen( $this->sought_class_name ) ];
-
-                    if ( ' ' !== $character && "\t" !== $character && "\f" !== $character && "\r" !== $character && "\n" !== $character ) {
-                        $class_at += strlen( $this->sought_class_name );
-                        continue;
-                    }
-                }
-
-                return true;
-            }
-
-            return false;
-        }
-
         return true;
     }