_wp_normalize_relative_css_links( string $css, string $stylesheet_url ): string
- Since
- 5.9.0
- Source
wp-includes/script-loader.php:3047
Compatibility
- WordPress
- since 5.9.0
- PHP
- 7.4–8.6-dev
- 6.7.7
- 6.8.8
- 6.9.7
- 7.0.4
- 7.1.0
Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.
Parameters
$cssstring- The CSS to make URLs relative to the WordPress installation.
$stylesheet_urlstring- The URL to the stylesheet.
Return value
string- The CSS with URLs made relative to the WordPress installation.
Performance profile
How much work a call to _wp_normalize_relative_css_links() 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
- Scaling
- Constant
- Instructions
- 10–28
- Plugin surface
- None
- Called by
- 1
Touches nothing outside its own arguments.
No loop in the body: the same number of instructions runs whatever you pass in.
Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 40.
Nothing here hands control to plugin code.
1 place in core call this, so the cost is paid more often than your own code shows.
What one call costs · 2 distinct outcomes
One number would be a lie: the work depends on which branch runs. These are every distinct cost _wp_normalize_relative_css_links() can have, taken from its control-flow graph on PHP 8.5.
| When | Instructions | Calls it makes |
|---|---|---|
$url | 10–18 | none |
!$url | 28 | wp_make_link_relative() |
Across PHP versions
| PHP | Compiled | Executed | Branches | Notes |
|---|---|---|---|---|
| 8.6-dev | 40 | 10–28 | 5 | |
| 8.5 | 40 | 10–28 | 5 | |
| 8.4 | 40 | 10–28 | 5 | 20 fewer instructions than PHP 8.3 |
| 8.3 | 60 | 13–48 | 5 | |
| 8.2 | 60 | 13–48 | 5 | 2 fewer instructions than PHP 8.1 |
| 8.1 | 62 | 15–50 | 5 | |
| 7.4 | 62 | 15–50 | 5 |
An instruction is not a fixed amount of time, so a matching count is not necessarily the same speed; what it rules out is a difference in the work itself.
Uses · 2
- str_starts_with()Polyfill for `str_starts_with()` function added in PHP 8.0.
- wp_make_link_relative()Converts full URL paths to absolute paths.
Used by · 1
- wp_maybe_inline_styles()Allows small styles to be inlined.
Source code
function _wp_normalize_relative_css_links( $css, $stylesheet_url ) { return preg_replace_callback( '#(url\s*\(\s*[\'"]?\s*)([^\'"\)]+)#', static function ( $matches ) use ( $stylesheet_url ) { list( , $prefix, $url ) = $matches; // Short-circuit if the URL does not require normalization. if ( str_starts_with( $url, 'http:' ) || str_starts_with( $url, 'https:' ) || str_starts_with( $url, '/' ) || str_starts_with( $url, '#' ) || str_starts_with( $url, 'data:' ) ) { return $matches[0]; } // Build the absolute URL. $absolute_url = dirname( $stylesheet_url ) . '/' . $url; $absolute_url = str_replace( '/./', '/', $absolute_url ); // Convert to URL related to the site root. $url = wp_make_link_relative( $absolute_url ); return $prefix . $url; }, $css );}Changelog
Introduced in 5.9.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
About this page
- Parsed data
- Generated from the wordpress-develop 6.7.7 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
- Something wrong on this page? Report it and it gets fixed in the next regeneration.