1<?php
2/**
3 * Post revision functions.
4 *
5 * @package WordPress
6 * @subpackage Post_Revisions
7 */
8
9/**
10 * Determines which fields of posts are to be saved in revisions.
11 *
12 * @since 2.6.0
13 * @since 4.5.0 A `WP_Post` object can now be passed to the `$post` parameter.
14 * @since 4.5.0 The optional `$autosave` parameter was deprecated and renamed to `$deprecated`.
15 * @access private
16 *
17 * @param array|WP_Post $post Optional. A post array or a WP_Post object being processed
18 * for insertion as a post revision. Default empty array.
19 * @param bool $deprecated Not used.
20 * @return string[] Array of fields that can be versioned.
21 */
22function _wp_post_revision_fields( $post = array(), $deprecated = false ) {
23 static $fields = null;
24
25 if ( ! is_array( $post ) ) {
26 $post = get_post( $post, ARRAY_A );
27 }
28
29 if ( is_null( $fields ) ) {
30 // Allow these to be versioned.
31 $fields = array(
32 'post_title' => __( 'Title' ),
33 'post_content' => __( 'Content' ),
34 'post_excerpt' => __( 'Excerpt' ),
35 );
36 }
37
38 /**
39 * Filters the list of fields saved in post revisions.
40 *
41 * Included by default: 'post_title', 'post_content' and 'post_excerpt'.
42 *
43 * Disallowed fields: 'ID', 'post_name', 'post_parent', 'post_date',
44 * 'post_date_gmt', 'post_status', 'post_type', 'comment_count',
45 * and 'post_author'.
46 *
47 * @since 2.6.0
48 * @since 4.5.0 The `$post` parameter was added.
49 *
50 * @param string[] $fields List of fields to revision. Contains 'post_title',
51 * 'post_content', and 'post_excerpt' by default.
52 * @param array $post A post array being processed for insertion as a post revision.
53 */
54 $fields = apply_filters( '_wp_post_revision_fields', $fields, $post );
55
56 // WP uses these internally either in versioning or elsewhere - they cannot be versioned.
57 foreach ( array( 'ID', 'post_name', 'post_parent', 'post_date', 'post_date_gmt', 'post_status', 'post_type', 'comment_count', 'post_author' ) as $protect ) {
58 unset( $fields[ $protect ] );
59 }
60
61 return $fields;
62}
63
64/**
65 * Returns a post array ready to be inserted into the posts table as a post revision.
66 *
67 * @since 4.5.0
68 * @access private
69 *
70 * @param array|WP_Post $post Optional. A post array or a WP_Post object to be processed
71 * for insertion as a post revision. Default empty array.
72 * @param bool $autosave Optional. Is the revision an autosave? Default false.
73 * @return array Post array ready to be inserted as a post revision.
74 */
75function _wp_post_revision_data( $post = array(), $autosave = false ) {
76 if ( ! is_array( $post ) ) {
77 $post = get_post( $post, ARRAY_A );
78 }
79
80 $fields = _wp_post_revision_fields( $post );
81
82 $revision_data = array();
83
84 foreach ( array_intersect( array_keys( $post ), array_keys( $fields ) ) as $field ) {
85 $revision_data[ $field ] = $post[ $field ];
86 }
87
88 $revision_data['post_parent'] = $post['ID'];
89 $revision_data['post_status'] = 'inherit';
90 $revision_data['post_type'] = 'revision';
91 $revision_data['post_name'] = $autosave ? "$post[ID]-autosave-v1" : "$post[ID]-revision-v1"; // "1" is the revisioning system version.
92 $revision_data['post_date'] = isset( $post['post_modified'] ) ? $post['post_modified'] : '';
93 $revision_data['post_date_gmt'] = isset( $post['post_modified_gmt'] ) ? $post['post_modified_gmt'] : '';
94
95 return $revision_data;
96}
97
98/**
99 * Saves revisions for a post after all changes have been made.
100 *
101 * @since 6.4.0
102 *
103 * @param int $post_id The post id that was inserted.
104 * @param WP_Post $post The post object that was inserted.
105 * @param bool $update Whether this insert is updating an existing post.
106 */
107function wp_save_post_revision_on_insert( $post_id, $post, $update ) {
108 if ( ! $update ) {
109 return;
110 }
111
112 if ( ! has_action( 'post_updated', 'wp_save_post_revision' ) ) {
113 return;
114 }
115
116 wp_save_post_revision( $post_id );
117}
118
119/**
120 * Creates a revision for the current version of a post.
121 *
122 * Typically used immediately after a post update, as every update is a revision,
123 * and the most recent revision always matches the current post.
124 *
125 * @since 2.6.0
126 *
127 * @param int $post_id The ID of the post to save as a revision.
128 * @return int|WP_Error|void Void or 0 if error, new revision ID, if success.
129 */
130function wp_save_post_revision( $post_id ) {
131 if ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE ) {
132 return;
133 }
134
135 // Prevent saving post revisions if revisions should be saved on wp_after_insert_post.
136 if ( doing_action( 'post_updated' ) && has_action( 'wp_after_insert_post', 'wp_save_post_revision_on_insert' ) ) {
137 return;
138 }
139
140 $post = get_post( $post_id );
141
142 if ( ! $post ) {
143 return;
144 }
145
146 if ( ! post_type_supports( $post->post_type, 'revisions' ) ) {
147 return;
148 }
149
150 if ( 'auto-draft' === $post->post_status ) {
151 return;
152 }
153
154 if ( ! wp_revisions_enabled( $post ) ) {
155 return;
156 }
157
158 /*
159 * Compare the proposed update with the last stored revision verifying that
160 * they are different, unless a plugin tells us to always save regardless.
161 * If no previous revisions, save one.
162 */
163 $revisions = wp_get_post_revisions( $post_id );
164 if ( $revisions ) {
165 // Grab the latest revision, but not an autosave.
166 foreach ( $revisions as $revision ) {
167 if ( str_contains( $revision->post_name, "{$revision->post_parent}-revision" ) ) {
168 $latest_revision = $revision;
169 break;
170 }
171 }
172
173 /**
174 * Filters whether the post has changed since the latest revision.
175 *
176 * By default a revision is saved only if one of the revisioned fields has changed.
177 * This filter can override that so a revision is saved even if nothing has changed.
178 *
179 * @since 3.6.0
180 *
181 * @param bool $check_for_changes Whether to check for changes before saving a new revision.
182 * Default true.
183 * @param WP_Post $latest_revision The latest revision post object.
184 * @param WP_Post $post The post object.
185 */
186 if ( isset( $latest_revision ) && apply_filters( 'wp_save_post_revision_check_for_changes', true, $latest_revision, $post ) ) {
187 $post_has_changed = false;
188
189 foreach ( array_keys( _wp_post_revision_fields( $post ) ) as $field ) {
190 if ( normalize_whitespace( $post->$field ) !== normalize_whitespace( $latest_revision->$field ) ) {
191 $post_has_changed = true;
192 break;
193 }
194 }
195
196 /**
197 * Filters whether a post has changed.
198 *
199 * By default a revision is saved only if one of the revisioned fields has changed.
200 * This filter allows for additional checks to determine if there were changes.
201 *
202 * @since 4.1.0
203 *
204 * @param bool $post_has_changed Whether the post has changed.
205 * @param WP_Post $latest_revision The latest revision post object.
206 * @param WP_Post $post The post object.
207 */
208 $post_has_changed = (bool) apply_filters( 'wp_save_post_revision_post_has_changed', $post_has_changed, $latest_revision, $post );
209
210 // Don't save revision if post unchanged.
211 if ( ! $post_has_changed ) {
212 return;
213 }
214 }
215 }
216
217 $return = _wp_put_post_revision( $post );
218
219 /*
220 * If a limit for the number of revisions to keep has been set,
221 * delete the oldest ones.
222 */
223 $revisions_to_keep = wp_revisions_to_keep( $post );
224
225 if ( $revisions_to_keep < 0 ) {
226 return $return;
227 }
228
229 $revisions = wp_get_post_revisions( $post_id, array( 'order' => 'ASC' ) );
230
231 /**
232 * Filters the revisions to be considered for deletion.
233 *
234 * @since 6.2.0
235 *
236 * @param WP_Post[] $revisions Array of revisions, or an empty array if none.
237 * @param int $post_id The ID of the post to save as a revision.
238 */
239 $revisions = apply_filters(
240 'wp_save_post_revision_revisions_before_deletion',
241 $revisions,
242 $post_id
243 );
244
245 $delete = count( $revisions ) - $revisions_to_keep;
246
247 if ( $delete < 1 ) {
248 return $return;
249 }
250
251 $revisions = array_slice( $revisions, 0, $delete );
252
253 for ( $i = 0; isset( $revisions[ $i ] ); $i++ ) {
254 if ( str_contains( $revisions[ $i ]->post_name, 'autosave' ) ) {
255 continue;
256 }
257
258 wp_delete_post_revision( $revisions[ $i ]->ID );
259 }
260
261 return $return;
262}
263
264/**
265 * Retrieves the autosaved data of the specified post.
266 *
267 * Returns a post object with the information that was autosaved for the specified post.
268 * If the optional $user_id is passed, returns the autosave for that user, otherwise
269 * returns the latest autosave.
270 *
271 * @since 2.6.0
272 *
273 * @param int $post_id The post ID.
274 * @param int $user_id Optional. The post author ID. Default 0.
275 * @return WP_Post|false The autosaved data or false on failure or when no autosave exists.
276 */
277function wp_get_post_autosave( $post_id, $user_id = 0 ) {
278 $args = array(
279 'post_type' => 'revision',
280 'post_status' => 'inherit',
281 'post_parent' => $post_id,
282 'name' => $post_id . '-autosave-v1',
283 'posts_per_page' => 1,
284 'orderby' => 'date',
285 'order' => 'DESC',
286 'fields' => 'ids',
287 'no_found_rows' => true,
288 );
289
290 if ( 0 !== $user_id ) {
291 $args['author'] = $user_id;
292 }
293
294 $query = new WP_Query( $args );
295
296 if ( ! $query->have_posts() ) {
297 return false;
298 }
299
300 return get_post( $query->posts[0] );
301}
302
303/**
304 * Determines if the specified post is a revision.
305 *
306 * @since 2.6.0
307 *
308 * @param int|WP_Post $post Post ID or post object.
309 * @return int|false ID of revision's parent on success, false if not a revision.
310 */
311function wp_is_post_revision( $post ) {
312 $post = wp_get_post_revision( $post );
313
314 if ( ! $post ) {
315 return false;
316 }
317
318 return (int) $post->post_parent;
319}
320
321/**
322 * Determines if the specified post is an autosave.
323 *
324 * @since 2.6.0
325 *
326 * @param int|WP_Post $post Post ID or post object.
327 * @return int|false ID of autosave's parent on success, false if not a revision.
328 */
329function wp_is_post_autosave( $post ) {
330 $post = wp_get_post_revision( $post );
331
332 if ( ! $post ) {
333 return false;
334 }
335
336 if ( str_contains( $post->post_name, "{$post->post_parent}-autosave" ) ) {
337 return (int) $post->post_parent;
338 }
339
340 return false;
341}
342
343/**
344 * Inserts post data into the posts table as a post revision.
345 *
346 * @since 2.6.0
347 * @access private
348 *
349 * @param int|WP_Post|array|null $post Post ID, post object OR post array.
350 * @param bool $autosave Optional. Whether the revision is an autosave or not.
351 * Default false.
352 * @return int|WP_Error WP_Error or 0 if error, new revision ID if success.
353 */
354function _wp_put_post_revision( $post = null, $autosave = false ) {
355 if ( is_object( $post ) ) {
356 $post = get_object_vars( $post );
357 } elseif ( ! is_array( $post ) ) {
358 $post = get_post( $post, ARRAY_A );
359 }
360
361 if ( ! $post || empty( $post['ID'] ) ) {
362 return new WP_Error( 'invalid_post', __( 'Invalid post ID.' ) );
363 }
364
365 if ( isset( $post['post_type'] ) && 'revision' === $post['post_type'] ) {
366 return new WP_Error( 'post_type', __( 'Cannot create a revision of a revision' ) );
367 }
368
369 $post = _wp_post_revision_data( $post, $autosave );
370 $post = wp_slash( $post ); // Since data is from DB.
371
372 $revision_id = wp_insert_post( $post, true );
373 if ( is_wp_error( $revision_id ) ) {
374 return $revision_id;
375 }
376
377 if ( $revision_id ) {
378 /**
379 * Fires once a revision has been saved.
380 *
381 * @since 2.6.0
382 * @since 6.4.0 The post_id parameter was added.
383 *
384 * @param int $revision_id Post revision ID.
385 * @param int $post_id Post ID.
386 */
387 do_action( '_wp_put_post_revision', $revision_id, $post['post_parent'] );
388 }
389
390 return $revision_id;
391}
392
393
394/**
395 * Save the revisioned meta fields.
396 *
397 * @since 6.4.0
398 *
399 * @param int $revision_id The ID of the revision to save the meta to.
400 * @param int $post_id The ID of the post the revision is associated with.
401 */
402function wp_save_revisioned_meta_fields( $revision_id, $post_id ) {
403 $post_type = get_post_type( $post_id );
404 if ( ! $post_type ) {
405 return;
406 }
407
408 foreach ( wp_post_revision_meta_keys( $post_type ) as $meta_key ) {
409 if ( metadata_exists( 'post', $post_id, $meta_key ) ) {
410 _wp_copy_post_meta( $post_id, $revision_id, $meta_key );
411 }
412 }
413}
414
415/**
416 * Gets a post revision.
417 *
418 * @since 2.6.0
419 *
420 * @param int|WP_Post $post Post ID or post object.
421 * @param string $output Optional. The required return type. One of OBJECT, ARRAY_A, or ARRAY_N, which
422 * correspond to a WP_Post object, an associative array, or a numeric array,
423 * respectively. Default OBJECT.
424 * @param string $filter Optional sanitization filter. See sanitize_post(). Default 'raw'.
425 * @return WP_Post|array|null WP_Post (or array) on success, or null on failure.
426 */
427function wp_get_post_revision( &$post, $output = OBJECT, $filter = 'raw' ) {
428 $revision = get_post( $post, OBJECT, $filter );
429
430 if ( ! $revision ) {
431 return $revision;
432 }
433
434 if ( 'revision' !== $revision->post_type ) {
435 return null;
436 }
437
438 if ( OBJECT === $output ) {
439 return $revision;
440 } elseif ( ARRAY_A === $output ) {
441 $_revision = get_object_vars( $revision );
442 return $_revision;
443 } elseif ( ARRAY_N === $output ) {
444 $_revision = array_values( get_object_vars( $revision ) );
445 return $_revision;
446 }
447
448 return $revision;
449}
450
451/**
452 * Restores a post to the specified revision.
453 *
454 * Can restore a past revision using all fields of the post revision, or only selected fields.
455 *
456 * @since 2.6.0
457 *
458 * @param int|WP_Post $revision Revision ID or revision object.
459 * @param array $fields Optional. What fields to restore from. Defaults to all.
460 * @return int|false|null Null if error, false if no fields to restore, (int) post ID if success.
461 */
462function wp_restore_post_revision( $revision, $fields = null ) {
463 $revision = wp_get_post_revision( $revision, ARRAY_A );
464
465 if ( ! $revision ) {
466 return $revision;
467 }
468
469 if ( ! is_array( $fields ) ) {
470 $fields = array_keys( _wp_post_revision_fields( $revision ) );
471 }
472
473 $update = array();
474 foreach ( array_intersect( array_keys( $revision ), $fields ) as $field ) {
475 $update[ $field ] = $revision[ $field ];
476 }
477
478 if ( ! $update ) {
479 return false;
480 }
481
482 $update['ID'] = $revision['post_parent'];
483
484 $update = wp_slash( $update ); // Since data is from DB.
485
486 $post_id = wp_update_post( $update );
487
488 if ( ! $post_id || is_wp_error( $post_id ) ) {
489 return $post_id;
490 }
491
492 // Update last edit user.
493 update_post_meta( $post_id, '_edit_last', get_current_user_id() );
494
495 /**
496 * Fires after a post revision has been restored.
497 *
498 * @since 2.6.0
499 *
500 * @param int $post_id Post ID.
501 * @param int $revision_id Post revision ID.
502 */
503 do_action( 'wp_restore_post_revision', $post_id, $revision['ID'] );
504
505 return $post_id;
506}
507
508/**
509 * Restore the revisioned meta values for a post.
510 *
511 * @since 6.4.0
512 *
513 * @param int $post_id The ID of the post to restore the meta to.
514 * @param int $revision_id The ID of the revision to restore the meta from.
515 */
516function wp_restore_post_revision_meta( $post_id, $revision_id ) {
517 $post_type = get_post_type( $post_id );
518 if ( ! $post_type ) {
519 return;
520 }
521
522 // Restore revisioned meta fields.
523 foreach ( wp_post_revision_meta_keys( $post_type ) as $meta_key ) {
524
525 // Clear any existing meta.
526 delete_post_meta( $post_id, $meta_key );
527
528 _wp_copy_post_meta( $revision_id, $post_id, $meta_key );
529 }
530}
531
532/**
533 * Copy post meta for the given key from one post to another.
534 *
535 * @since 6.4.0
536 *
537 * @param int $source_post_id Post ID to copy meta value(s) from.
538 * @param int $target_post_id Post ID to copy meta value(s) to.
539 * @param string $meta_key Meta key to copy.
540 */
541function _wp_copy_post_meta( $source_post_id, $target_post_id, $meta_key ) {
542
543 foreach ( get_post_meta( $source_post_id, $meta_key ) as $meta_value ) {
544 /**
545 * We use add_metadata() function vs add_post_meta() here
546 * to allow for a revision post target OR regular post.
547 */
548 add_metadata( 'post', $target_post_id, $meta_key, wp_slash( $meta_value ) );
549 }
550}
551
552/**
553 * Determine which post meta fields should be revisioned.
554 *
555 * @since 6.4.0
556 *
557 * @param string $post_type The post type being revisioned.
558 * @return array An array of meta keys to be revisioned.
559 */
560function wp_post_revision_meta_keys( $post_type ) {
561 $registered_meta = array_merge(
562 get_registered_meta_keys( 'post' ),
563 get_registered_meta_keys( 'post', $post_type )
564 );
565
566 $wp_revisioned_meta_keys = array();
567
568 foreach ( $registered_meta as $name => $args ) {
569 if ( $args['revisions_enabled'] ) {
570 $wp_revisioned_meta_keys[ $name ] = true;
571 }
572 }
573
574 $wp_revisioned_meta_keys = array_keys( $wp_revisioned_meta_keys );
575
576 /**
577 * Filter the list of post meta keys to be revisioned.
578 *
579 * @since 6.4.0
580 *
581 * @param array $keys An array of meta fields to be revisioned.
582 * @param string $post_type The post type being revisioned.
583 */
584 return apply_filters( 'wp_post_revision_meta_keys', $wp_revisioned_meta_keys, $post_type );
585}
586
587/**
588 * Check whether revisioned post meta fields have changed.
589 *
590 * @since 6.4.0
591 *
592 * @param bool $post_has_changed Whether the post has changed.
593 * @param WP_Post $last_revision The last revision post object.
594 * @param WP_Post $post The post object.
595 * @return bool Whether the post has changed.
596 */
597function wp_check_revisioned_meta_fields_have_changed( $post_has_changed, WP_Post $last_revision, WP_Post $post ) {
598 foreach ( wp_post_revision_meta_keys( $post->post_type ) as $meta_key ) {
599 if ( get_post_meta( $post->ID, $meta_key ) !== get_post_meta( $last_revision->ID, $meta_key ) ) {
600 $post_has_changed = true;
601 break;
602 }
603 }
604 return $post_has_changed;
605}
606
607/**
608 * Deletes a revision.
609 *
610 * Deletes the row from the posts table corresponding to the specified revision.
611 *
612 * @since 2.6.0
613 *
614 * @param int|WP_Post $revision Revision ID or revision object.
615 * @return WP_Post|false|null Null or false if error, deleted post object if success.
616 */
617function wp_delete_post_revision( $revision ) {
618 $revision = wp_get_post_revision( $revision );
619
620 if ( ! $revision ) {
621 return $revision;
622 }
623
624 $delete = wp_delete_post( $revision->ID );
625
626 if ( $delete ) {
627 /**
628 * Fires once a post revision has been deleted.
629 *
630 * @since 2.6.0
631 *
632 * @param int $revision_id Post revision ID.
633 * @param WP_Post $revision Post revision object.
634 */
635 do_action( 'wp_delete_post_revision', $revision->ID, $revision );
636 }
637
638 return $delete;
639}
640
641/**
642 * Returns all revisions of specified post.
643 *
644 * @since 2.6.0
645 *
646 * @see get_children()
647 *
648 * @param int|WP_Post $post Optional. Post ID or WP_Post object. Default is global `$post`.
649 * @param array|null $args Optional. Arguments for retrieving post revisions. Default null.
650 * @return WP_Post[]|int[] Array of revision objects or IDs, or an empty array if none.
651 */
652function wp_get_post_revisions( $post = 0, $args = null ) {
653 $post = get_post( $post );
654
655 if ( ! $post || empty( $post->ID ) ) {
656 return array();
657 }
658
659 $defaults = array(
660 'order' => 'DESC',
661 'orderby' => 'date ID',
662 'check_enabled' => true,
663 );
664 $args = wp_parse_args( $args, $defaults );
665
666 if ( $args['check_enabled'] && ! wp_revisions_enabled( $post ) ) {
667 return array();
668 }
669
670 $args = array_merge(
671 $args,
672 array(
673 'post_parent' => $post->ID,
674 'post_type' => 'revision',
675 'post_status' => 'inherit',
676 )
677 );
678
679 $revisions = get_children( $args );
680
681 if ( ! $revisions ) {
682 return array();
683 }
684
685 return $revisions;
686}
687
688/**
689 * Returns the latest revision ID and count of revisions for a post.
690 *
691 * @since 6.1.0
692 *
693 * @param int|WP_Post $post Optional. Post ID or WP_Post object. Default is global $post.
694 * @return array|WP_Error {
695 * Returns associative array with latest revision ID and total count,
696 * or a WP_Error if the post does not exist or revisions are not enabled.
697 *
698 * @type int $latest_id The latest revision post ID or 0 if no revisions exist.
699 * @type int $count The total count of revisions for the given post.
700 * }
701 */
702function wp_get_latest_revision_id_and_total_count( $post = 0 ) {
703 $post = get_post( $post );
704
705 if ( ! $post ) {
706 return new WP_Error( 'invalid_post', __( 'Invalid post.' ) );
707 }
708
709 if ( ! wp_revisions_enabled( $post ) ) {
710 return new WP_Error( 'revisions_not_enabled', __( 'Revisions not enabled.' ) );
711 }
712
713 $args = array(
714 'post_parent' => $post->ID,
715 'fields' => 'ids',
716 'post_type' => 'revision',
717 'post_status' => 'inherit',
718 'order' => 'DESC',
719 'orderby' => 'date ID',
720 'posts_per_page' => 1,
721 'ignore_sticky_posts' => true,
722 );
723
724 $revision_query = new WP_Query();
725 $revisions = $revision_query->query( $args );
726
727 if ( ! $revisions ) {
728 return array(
729 'latest_id' => 0,
730 'count' => 0,
731 );
732 }
733
734 return array(
735 'latest_id' => $revisions[0],
736 'count' => $revision_query->found_posts,
737 );
738}
739
740/**
741 * Returns the url for viewing and potentially restoring revisions of a given post.
742 *
743 * @since 5.9.0
744 *
745 * @param int|WP_Post $post Optional. Post ID or WP_Post object. Default is global `$post`.
746 * @return string|null The URL for editing revisions on the given post, otherwise null.
747 */
748function wp_get_post_revisions_url( $post = 0 ) {
749 $post = get_post( $post );
750
751 if ( ! $post instanceof WP_Post ) {
752 return null;
753 }
754
755 // If the post is a revision, return early.
756 if ( 'revision' === $post->post_type ) {
757 return get_edit_post_link( $post );
758 }
759
760 if ( ! wp_revisions_enabled( $post ) ) {
761 return null;
762 }
763
764 $revisions = wp_get_latest_revision_id_and_total_count( $post->ID );
765
766 if ( is_wp_error( $revisions ) || 0 === $revisions['count'] ) {
767 return null;
768 }
769
770 return get_edit_post_link( $revisions['latest_id'] );
771}
772
773/**
774 * Determines whether revisions are enabled for a given post.
775 *
776 * @since 3.6.0
777 *
778 * @param WP_Post $post The post object.
779 * @return bool True if number of revisions to keep isn't zero, false otherwise.
780 */
781function wp_revisions_enabled( $post ) {
782 return wp_revisions_to_keep( $post ) !== 0;
783}
784
785/**
786 * Determines how many revisions to retain for a given post.
787 *
788 * By default, an infinite number of revisions are kept.
789 *
790 * The constant WP_POST_REVISIONS can be set in wp-config to specify the limit
791 * of revisions to keep.
792 *
793 * @since 3.6.0
794 *
795 * @param WP_Post $post The post object.
796 * @return int The number of revisions to keep.
797 */
798function wp_revisions_to_keep( $post ) {
799 $num = WP_POST_REVISIONS;
800
801 if ( true === $num ) {
802 $num = -1;
803 } else {
804 $num = (int) $num;
805 }
806
807 if ( ! post_type_supports( $post->post_type, 'revisions' ) ) {
808 $num = 0;
809 }
810
811 /**
812 * Filters the number of revisions to save for the given post.
813 *
814 * Overrides the value of WP_POST_REVISIONS.
815 *
816 * @since 3.6.0
817 *
818 * @param int $num Number of revisions to store.
819 * @param WP_Post $post Post object.
820 */
821 $num = apply_filters( 'wp_revisions_to_keep', $num, $post );
822
823 /**
824 * Filters the number of revisions to save for the given post by its post type.
825 *
826 * Overrides both the value of WP_POST_REVISIONS and the {@see 'wp_revisions_to_keep'} filter.
827 *
828 * The dynamic portion of the hook name, `$post->post_type`, refers to
829 * the post type slug.
830 *
831 * Possible hook names include:
832 *
833 * - `wp_post_revisions_to_keep`
834 * - `wp_page_revisions_to_keep`
835 *
836 * @since 5.8.0
837 *
838 * @param int $num Number of revisions to store.
839 * @param WP_Post $post Post object.
840 */
841 $num = apply_filters( "wp_{$post->post_type}_revisions_to_keep", $num, $post );
842
843 return (int) $num;
844}
845
846/**
847 * Sets up the post object for preview based on the post autosave.
848 *
849 * @since 2.7.0
850 * @access private
851 *
852 * @param WP_Post $post
853 * @return WP_Post|false
854 */
855function _set_preview( $post ) {
856 if ( ! is_object( $post ) ) {
857 return $post;
858 }
859
860 $preview = wp_get_post_autosave( $post->ID );
861
862 if ( is_object( $preview ) ) {
863 $preview = sanitize_post( $preview );
864
865 $post->post_content = $preview->post_content;
866 $post->post_title = $preview->post_title;
867 $post->post_excerpt = $preview->post_excerpt;
868 }
869
870 add_filter( 'get_the_terms', '_wp_preview_terms_filter', 10, 3 );
871 add_filter( 'get_post_metadata', '_wp_preview_post_thumbnail_filter', 10, 3 );
872 add_filter( 'get_post_metadata', '_wp_preview_meta_filter', 10, 4 );
873
874 return $post;
875}
876
877/**
878 * Filters the latest content for preview from the post autosave.
879 *
880 * @since 2.7.0
881 * @access private
882 */
883function _show_post_preview() {
884 if ( isset( $_GET['preview_id'] ) && isset( $_GET['preview_nonce'] ) ) {
885 $id = (int) $_GET['preview_id'];
886
887 if ( false === wp_verify_nonce( $_GET['preview_nonce'], 'post_preview_' . $id ) ) {
888 wp_die( __( 'Sorry, you are not allowed to preview drafts.' ), 403 );
889 }
890
891 add_filter( 'the_preview', '_set_preview' );
892 }
893}
894
895/**
896 * Filters terms lookup to set the post format.
897 *
898 * @since 3.6.0
899 * @access private
900 *
901 * @param array $terms
902 * @param int $post_id
903 * @param string $taxonomy
904 * @return array
905 */
906function _wp_preview_terms_filter( $terms, $post_id, $taxonomy ) {
907 $post = get_post();
908
909 if ( ! $post ) {
910 return $terms;
911 }
912
913 if ( empty( $_REQUEST['post_format'] ) || $post->ID !== $post_id
914 || 'post_format' !== $taxonomy || 'revision' === $post->post_type
915 ) {
916 return $terms;
917 }
918
919 if ( 'standard' === $_REQUEST['post_format'] ) {
920 $terms = array();
921 } else {
922 $term = get_term_by( 'slug', 'post-format-' . sanitize_key( $_REQUEST['post_format'] ), 'post_format' );
923
924 if ( $term ) {
925 $terms = array( $term ); // Can only have one post format.
926 }
927 }
928
929 return $terms;
930}
931
932/**
933 * Filters post thumbnail lookup to set the post thumbnail.
934 *
935 * @since 4.6.0
936 * @access private
937 *
938 * @param null|array|string $value The value to return - a single metadata value, or an array of values.
939 * @param int $post_id Post ID.
940 * @param string $meta_key Meta key.
941 * @return null|array The default return value or the post thumbnail meta array.
942 */
943function _wp_preview_post_thumbnail_filter( $value, $post_id, $meta_key ) {
944 $post = get_post();
945
946 if ( ! $post ) {
947 return $value;
948 }
949
950 if ( empty( $_REQUEST['_thumbnail_id'] ) || empty( $_REQUEST['preview_id'] )
951 || $post->ID !== $post_id || $post_id !== (int) $_REQUEST['preview_id']
952 || '_thumbnail_id' !== $meta_key || 'revision' === $post->post_type
953 ) {
954 return $value;
955 }
956
957 $thumbnail_id = (int) $_REQUEST['_thumbnail_id'];
958
959 if ( $thumbnail_id <= 0 ) {
960 return '';
961 }
962
963 return (string) $thumbnail_id;
964}
965
966/**
967 * Gets the post revision version.
968 *
969 * @since 3.6.0
970 * @access private
971 *
972 * @param WP_Post $revision
973 * @return int|false
974 */
975function _wp_get_post_revision_version( $revision ) {
976 if ( is_object( $revision ) ) {
977 $revision = get_object_vars( $revision );
978 } elseif ( ! is_array( $revision ) ) {
979 return false;
980 }
981
982 if ( preg_match( '/^\d+-(?:autosave|revision)-v(\d+)$/', $revision['post_name'], $matches ) ) {
983 return (int) $matches[1];
984 }
985
986 return 0;
987}
988
989/**
990 * Upgrades the revisions author, adds the current post as a revision and sets the revisions version to 1.
991 *
992 * @since 3.6.0
993 * @access private
994 *
995 * @global wpdb $wpdb WordPress database abstraction object.
996 *
997 * @param WP_Post $post Post object.
998 * @param array $revisions Current revisions of the post.
999 * @return bool true if the revisions were upgraded, false if problems.
1000 */
1001function _wp_upgrade_revisions_of_post( $post, $revisions ) {
1002 global $wpdb;
1003
1004 // Add post option exclusively.
1005 $lock = "revision-upgrade-{$post->ID}";
1006 $now = time();
1007 $result = $wpdb->query( $wpdb->prepare( "INSERT IGNORE INTO `$wpdb->options` (`option_name`, `option_value`, `autoload`) VALUES (%s, %s, 'off') /* LOCK */", $lock, $now ) );
1008
1009 if ( ! $result ) {
1010 // If we couldn't get a lock, see how old the previous lock is.
1011 $locked = get_option( $lock );
1012
1013 if ( ! $locked ) {
1014 /*
1015 * Can't write to the lock, and can't read the lock.
1016 * Something broken has happened.
1017 */
1018 return false;
1019 }
1020
1021 if ( $locked > $now - HOUR_IN_SECONDS ) {
1022 // Lock is not too old: some other process may be upgrading this post. Bail.
1023 return false;
1024 }
1025
1026 // Lock is too old - update it (below) and continue.
1027 }
1028
1029 // If we could get a lock, re-"add" the option to fire all the correct filters.
1030 update_option( $lock, $now );
1031
1032 reset( $revisions );
1033 $add_last = true;
1034
1035 do {
1036 $this_revision = current( $revisions );
1037 $prev_revision = next( $revisions );
1038
1039 $this_revision_version = _wp_get_post_revision_version( $this_revision );
1040
1041 // Something terrible happened.
1042 if ( false === $this_revision_version ) {
1043 continue;
1044 }
1045
1046 /*
1047 * 1 is the latest revision version, so we're already up to date.
1048 * No need to add a copy of the post as latest revision.
1049 */
1050 if ( 0 < $this_revision_version ) {
1051 $add_last = false;
1052 continue;
1053 }
1054
1055 // Always update the revision version.
1056 $update = array(
1057 'post_name' => preg_replace( '/^(\d+-(?:autosave|revision))[\d-]*$/', '$1-v1', $this_revision->post_name ),
1058 );
1059
1060 /*
1061 * If this revision is the oldest revision of the post, i.e. no $prev_revision,
1062 * the correct post_author is probably $post->post_author, but that's only a good guess.
1063 * Update the revision version only and Leave the author as-is.
1064 */
1065 if ( $prev_revision ) {
1066 $prev_revision_version = _wp_get_post_revision_version( $prev_revision );
1067
1068 // If the previous revision is already up to date, it no longer has the information we need :(
1069 if ( $prev_revision_version < 1 ) {
1070 $update['post_author'] = $prev_revision->post_author;
1071 }
1072 }
1073
1074 // Upgrade this revision.
1075 $result = $wpdb->update( $wpdb->posts, $update, array( 'ID' => $this_revision->ID ) );
1076
1077 if ( $result ) {
1078 wp_cache_delete( $this_revision->ID, 'posts' );
1079 }
1080 } while ( $prev_revision );
1081
1082 delete_option( $lock );
1083
1084 // Add a copy of the post as latest revision.
1085 if ( $add_last ) {
1086 wp_save_post_revision( $post->ID );
1087 }
1088
1089 return true;
1090}
1091
1092/**
1093 * Filters preview post meta retrieval to get values from the autosave.
1094 *
1095 * Filters revisioned meta keys only.
1096 *
1097 * @since 6.4.0
1098 *
1099 * @param mixed $value Meta value to filter.
1100 * @param int $object_id Object ID.
1101 * @param string $meta_key Meta key to filter a value for.
1102 * @param bool $single Whether to return a single value.
1103 * @return mixed Original meta value if the meta key isn't revisioned, the object doesn't exist,
1104 * the post type is a revision or the post ID doesn't match the object ID.
1105 * Otherwise, the revisioned meta value is returned for the preview.
1106 */
1107function _wp_preview_meta_filter( $value, $object_id, $meta_key, $single ) {
1108 $post = get_post();
1109
1110 if ( empty( $post )
1111 || $post->ID !== $object_id
1112 || ! in_array( $meta_key, wp_post_revision_meta_keys( $post->post_type ), true )
1113 || 'revision' === $post->post_type
1114 ) {
1115 return $value;
1116 }
1117
1118 $preview = wp_get_post_autosave( $post->ID );
1119
1120 if ( false === $preview ) {
1121 return $value;
1122 }
1123
1124 return get_post_meta( $preview->ID, $meta_key, $single );
1125}
1126