_wp_preview_meta_filter( mixed $value, int $object_id, string $meta_key, bool $single ): mixed
- Since
- 6.4.0
- Source
wp-includes/revision.php:1121
Description
Filters revisioned meta keys only.
Compatibility
- WordPress
- since 6.4.0
- 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
$valuemixed- Meta value to filter.
$object_idint- Object ID.
$meta_keystring- Meta key to filter a value for.
$singlebool- Whether to return a single value.
Return value
mixed- Original meta value if the meta key isn't revisioned, the object doesn't exist, the post type is a revision or the post ID doesn't match the object ID.
Otherwise, the revisioned meta value is returned for the preview.
Performance profile
How much work a call to _wp_preview_meta_filter() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.
- Cost class
- Heavy
- Scaling
- Constant
- Instructions
- 10–39
- Plugin surface
- None
- Called by
- 0
Reaches the database via get_post().
No loop in the body: the same number of instructions runs whatever you pass in.
Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 41.
Nothing here hands control to plugin code.
Nothing in core calls this; the cost is only what you spend yourself.
What it touches
- querycontent query
get_post()called directly - hookthird-party callbacks
apply_filters()one call below _wp_preview_meta_filter()
Further down the call graph this can also reach cache, serialize, option and transient. Those are the worst case, several calls deep and usually down an error path, not what a normal call pays.
What one call costs · 4 distinct outcomes
One number would be a lie: the work depends on which branch runs. These are every distinct cost _wp_preview_meta_filter() can have, taken from its control-flow graph on PHP 8.5.
| When | Instructions | Calls it makes |
|---|---|---|
| always | 10–13 | get_post() |
!empty($post) && $object_id === false | 21–24 | get_post(), wp_post_revision_meta_keys() |
!empty($post) && $object_id === false && $meta_key && $preview === false | 32 | get_post(), wp_post_revision_meta_keys(), wp_get_post_autosave() |
!empty($post) && $object_id === false && $meta_key && $preview !== false | 39 | get_post(), wp_post_revision_meta_keys(), wp_get_post_autosave(), get_post_meta() |
Across PHP versions
| PHP | Compiled | Executed | Branches | Notes |
|---|---|---|---|---|
| 8.6-dev | 41 | 10–39 | 5 | |
| 8.5 | 41 | 10–39 | 5 | |
| 8.4 | 41 | 10–39 | 5 | 3 fewer instructions than PHP 8.3 |
| 8.3 | 44 | 10–42 | 5 | |
| 8.2 | 44 | 10–42 | 5 | |
| 8.1 | 44 | 10–42 | 5 | |
| 7.4 | 44 | 10–42 | 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 · 4
- get_post()Retrieves post data given a post ID or post object.
- wp_post_revision_meta_keys()Determine which post meta fields should be revisioned.
- wp_get_post_autosave()Retrieves the autosaved data of the specified post.
- get_post_meta()Retrieves a post meta field for the given post ID.
Source code
function _wp_preview_meta_filter( $value, $object_id, $meta_key, $single ) { $post = get_post(); if ( empty( $post ) || $post->ID !== $object_id || ! in_array( $meta_key, wp_post_revision_meta_keys( $post->post_type ), true ) || 'revision' === $post->post_type ) { return $value; } $preview = wp_get_post_autosave( $post->ID ); if ( false === $preview ) { return $value; } return get_post_meta( $preview->ID, $meta_key, $single );}Changelog
Introduced in 6.4.0. 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 7.1.0 tag, from
src/wp-includes/revision.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.