wp_maybe_add_fetchpriority_high_attr( $loading_attrs, string $tag_name, $attr ): array<string,

Compatibility

Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.

Parameters

$loading_attrs

$tag_namestring

The tag name.

$attr

Return value

array<string,

string> Updated loading optimization attributes for the element.

Performance profile

How much work a call to wp_maybe_add_fetchpriority_high_attr() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.

Cost class

Trivial

Touches nothing outside its own arguments.

Scaling

Constant

No loop in the body: the same number of instructions runs whatever you pass in.

Instructions

6–39

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 50.

Plugin surface

1 hook

Third-party callbacks on 'wp_min_priority_img_pixels' run inside this call, and their cost is not bounded by anything here.

Called by

1

1 place in core call this, so the cost is paid more often than your own code shows.

What it touches

• hookthird-party callbacksapply_filters()called directly

What one call costs · 4 distinct outcomes

One number would be a lie: the work depends on which branch runs. These are every distinct cost wp_maybe_add_fetchpriority_high_attr() can have, taken from its control-flow graph on PHP 8.5.

Hooks and filters fired · 1

One hook fires while wp_maybe_add_fetchpriority_high_attr() runs, in this order:

1. 1
   apply_filters( wp_min_priority_img_pixels )filterline 6501 (+40 into the body)

   Filters the minimum square-pixels threshold for an image to be eligible as the high-priority image.

Uses · 2

• wp_high_priority_element_flag()Accesses a flag that indicates if an element is a possible candidate for `fetchpriority='high'`.
• apply_filters()Calls the callback functions that have been added to a filter hook.

Used by · 1

• wp_get_loading_optimization_attributes()Gets loading optimization attributes.

Source code

View on Trac ↗View on GitHub ↗

6461function wp_maybe_add_fetchpriority_high_attr( $loading_attrs, $tag_name, $attr ) {6462	// For now, adding `fetchpriority="high"` is only supported for images.6463	if ( 'img' !== $tag_name ) {6464		return $loading_attrs;6465	}6466 6467	$existing_fetchpriority = $attr['fetchpriority'] ?? null;6468	if ( null !== $existing_fetchpriority && 'auto' !== $existing_fetchpriority ) {6469		/*6470		 * When an IMG has been explicitly marked with `fetchpriority=high`, then honor that this is the element that6471		 * should have the priority. In contrast, the Navigation block may add `fetchpriority=low` to an IMG which6472		 * appears in the Navigation Overlay; such images should never be considered candidates for6473		 * `fetchpriority=high`. Lastly, block visibility may add `fetchpriority=auto` to an IMG when the block is6474		 * conditionally displayed based on viewport size. Such an image is considered an LCP element candidate if it6475		 * exceeds the threshold for the minimum number of square pixels.6476		 */6477		if ( 'high' === $existing_fetchpriority ) {6478			$loading_attrs['fetchpriority'] = 'high';6479			wp_high_priority_element_flag( false );6480		}6481 6482		return $loading_attrs;6483	}6484 6485	// Lazy-loading and `fetchpriority="high"` are mutually exclusive.6486	if ( isset( $loading_attrs['loading'] ) && 'lazy' === $loading_attrs['loading'] ) {6487		return $loading_attrs;6488	}6489 6490	if ( ! wp_high_priority_element_flag() ) {6491		return $loading_attrs;6492	}6493 6494	/**6495	 * Filters the minimum square-pixels threshold for an image to be eligible as the high-priority image.6496	 *6497	 * @since 6.3.06498	 *6499	 * @param int $threshold Minimum square-pixels threshold. Default 50000.6500	 */6501	$wp_min_priority_img_pixels = apply_filters( 'wp_min_priority_img_pixels', 50000 );6502 6503	if ( $wp_min_priority_img_pixels <= $attr['width'] * $attr['height'] ) {6504		if ( 'auto' !== $existing_fetchpriority ) {6505			$loading_attrs['fetchpriority'] = 'high';6506		}6507		wp_high_priority_element_flag( false );6508	}6509 6510	return $loading_attrs;6511}

Changelog

Introduced in 6.3.0. 3 changes between 6.7.7 and 7.1.0.

1. 6.7.7
2. 6.8.8
3. 6.9.7
4. 7.0.4
5. 7.1.0

Signature, return type and hooks compared across 5 parsed releases.

About this page

Parsed data

Generated from the wordpress-develop 7.1.0 tag, from src/wp-includes/media.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

Corrections

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