wp_hoist_late_printed_styles()

Compatibility

Present in 3 of the 5 tracked releases, added in 6.9.0, and compiles on PHP 7.4 through 8.6-dev.

Performance profile

How much work a call to wp_hoist_late_printed_styles() 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

Light

Touches nothing outside its own arguments.

Scaling

Scales with input

The body loops, so the work grows with how much data it finds.

Instructions

47–131

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 418.

Plugin surface

None

Nothing here hands control to plugin code.

Called by

0

Nothing in core calls this; the cost is only what you spend yourself.

What it touches

• hookthird-party callbacksapply_filters()one call below wp_hoist_late_printed_styles()

Further down the call graph this can also reach option, cache, serialize, query and transient. Those are the worst case, several calls deep and usually down an error path, not what a normal call pays.

What one call costs · 132 distinct outcomes

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

This body has more branch combinations than are worth enumerating, so the table covers the outcomes found first rather than every one that exists.

Uses · 15

• is_embed()Is the query for an embedded post?
• add_action()Adds a callback function to an action hook.
• wp_styles()Initializes $wp_styles if it has not been set.
• wp_add_inline_style()Adds extra CSS styles to a registered stylesheet.
• str_starts_with()Polyfill for `str_starts_with()` function added in PHP 8.0.
• wp_style_is()Checks whether a CSS stylesheet has been added to the queue.
• has_action()Checks if any action has been registered for a hook.
• remove_action()Removes a callback function from an action hook.
• print_footer_scripts()Prints the scripts that were queued for the footer or too late for the HTML head.
• add_filter()Adds a callback function to a filter hook.
• WP_Block_Type_Registry::get_instance()::get_all_registered()
• WP_Block_Type_Registry::get_instance()Utility method to retrieve the main instance of the class.

Source code

View on Trac ↗View on GitHub ↗

3640function wp_hoist_late_printed_styles() {3641	// Skip the embed template on-demand styles aren't relevant, and there is no wp_head action.3642	if ( is_embed() ) {3643		return;3644	}3645 3646	// Capture the styles enqueued at the enqueue_block_assets action, so that non-core block styles and global styles can be inserted afterwards during hoisting.3647	$style_handles_at_enqueue_block_assets = array();3648	add_action(3649		'enqueue_block_assets',3650		static function () use ( &$style_handles_at_enqueue_block_assets ) {3651			$style_handles_at_enqueue_block_assets = wp_styles()->queue;3652		},3653		PHP_INT_MIN3654	);3655	add_action(3656		'enqueue_block_assets',3657		static function () use ( &$style_handles_at_enqueue_block_assets ) {3658			$style_handles_at_enqueue_block_assets = array_values( array_diff( wp_styles()->queue, $style_handles_at_enqueue_block_assets ) );3659		},3660		PHP_INT_MAX3661	);3662 3663	/*3664	 * Add a placeholder comment into the inline styles for wp-block-library, after which the late block styles3665	 * can be hoisted from the footer to be printed in the header by means of a filter below on the template enhancement3666	 * output buffer. The `wp_print_styles` action is used to ensure that if the inline style gets replaced at3667	 * `enqueue_block_assets` or `wp_enqueue_scripts` that the placeholder will be sure to be present.3668	 */3669	$placeholder = sprintf( '/*%s*/', uniqid( 'wp_block_styles_on_demand_placeholder:' ) );3670	add_action(3671		'wp_print_styles',3672		static function () use ( $placeholder ) {3673			wp_add_inline_style( 'wp-block-library', $placeholder );3674		}3675	);3676 3677	/*3678	 * Create a substitute for `print_late_styles()` which is aware of block styles. This substitute does not print3679	 * the styles, but it captures what would be printed for block styles and non-block styles so that they can be3680	 * later hoisted to the HEAD in the template enhancement output buffer. This will run at `wp_print_footer_scripts`3681	 * before `print_footer_scripts()` is called.3682	 */3683	$printed_core_block_styles  = '';3684	$printed_other_block_styles = '';3685	$printed_global_styles      = '';3686	$printed_late_styles        = '';3687 3688	$capture_late_styles = static function () use ( &$printed_core_block_styles, &$printed_other_block_styles, &$printed_global_styles, &$printed_late_styles ) {3689		// Gather the styles related to on-demand block enqueues.3690		$all_core_block_style_handles  = array();3691		$all_other_block_style_handles = array();3692		foreach ( WP_Block_Type_Registry::get_instance()->get_all_registered() as $block_type ) {3693			if ( str_starts_with( $block_type->name, 'core/' ) ) {3694				foreach ( $block_type->style_handles as $style_handle ) {3695					$all_core_block_style_handles[] = $style_handle;3696				}3697			} else {3698				foreach ( $block_type->style_handles as $style_handle ) {3699					$all_other_block_style_handles[] = $style_handle;3700				}3701			}3702		}3703 3704		/*3705		 * First print all styles related to blocks which should be inserted right after the wp-block-library stylesheet3706		 * to preserve the CSS cascade. The logic in this `if` statement is derived from `wp_print_styles()`.3707		 */3708		$enqueued_core_block_styles = array_values( array_intersect( $all_core_block_style_handles, wp_styles()->queue ) );3709		if ( count( $enqueued_core_block_styles ) > 0 ) {3710			ob_start();3711			wp_styles()->do_items( $enqueued_core_block_styles );3712			$printed_core_block_styles = ob_get_clean();3713		}3714 3715		// Non-core block styles get printed after the classic-theme-styles stylesheet.3716		$enqueued_other_block_styles = array_values( array_intersect( $all_other_block_style_handles, wp_styles()->queue ) );3717		if ( count( $enqueued_other_block_styles ) > 0 ) {3718			ob_start();3719			wp_styles()->do_items( $enqueued_other_block_styles );

Changelog

Introduced in 6.9.0. Unchanged from 6.9.10 through 7.1.3.

1. 6.9.10
2. 7.0.7
3. 7.1.3

Signature, return type and hooks compared across 3 parsed releases.

About this page

Parsed data

Generated from the wordpress-develop 6.9.10 tag, from src/wp-includes/script-loader.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

Corrections

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