<?php
/**
* グローバルの$postを利用しないようにする
*
*
* Retrieve adjacent post.
*
* Can either be next or previous post.
*
* @since 2.5.0
* @see get_adjacent_post()
*
* @param int|object 投稿IDか投稿オブジェクト
* @param bool $in_same_cat Optional. Whether post should be in a same category.
* @param array|string $excluded_categories Optional. Array or comma-separated list of excluded category IDs.
* @param bool $previous Optional. Whether to retrieve previous post.
* @return mixed Post object if successful. Null if global $post is not set. Empty string if no corresponding post exists.
*/
function my_get_adjacent_post($postdata = null, $in_same_cat = false, $excluded_categories = '', $previous = true ) {
global $wpdb;
if (is_null($postdata)) {
global $post;
} else {
if (is_numeric($postdata)) {
$post = get_post($postdata = (int) $postdata, OBJECT);
} elseif ($postdata instanceof stdClass && is_propety('post_type', $postdata) && $postdata->post_type === 'post') {
$post = $postdata;
}
}
if ( empty( $post ) )
return null;
$current_post_date = $post->post_date;
$join = '';
$posts_in_ex_cats_sql = '';
if ( $in_same_cat || ! empty( $excluded_categories ) ) {
$join = " INNER JOIN $wpdb->term_relationships AS tr ON p.ID = tr.object_id INNER JOIN $wpdb->term_taxonomy tt ON tr.term_taxonomy_id = tt.term_taxonomy_id";
if ( $in_same_cat ) {
$cat_array = wp_get_object_terms($post->ID, 'category', array('fields' => 'ids'));
$join .= " AND tt.taxonomy = 'category' AND tt.term_id IN (" . implode(',', $cat_array) . ")";
}
$posts_in_ex_cats_sql = "AND tt.taxonomy = 'category'";
if ( ! empty( $excluded_categories ) ) {
if ( ! is_array( $excluded_categories ) ) {
// back-compat, $excluded_categories used to be IDs separated by " and "
if ( strpos( $excluded_categories, ' and ' ) !== false ) {
_deprecated_argument( __FUNCTION__, '3.3', sprintf( __( 'Use commas instead of %s to separate excluded categories.' ), "'and'" ) );
$excluded_categories = explode( ' and ', $excluded_categories );
} else {
$excluded_categories = explode( ',', $excluded_categories );
}
}
$excluded_categories = array_map( 'intval', $excluded_categories );
if ( ! empty( $cat_array ) ) {
$excluded_categories = array_diff($excluded_categories, $cat_array);
$posts_in_ex_cats_sql = '';
}
if ( !empty($excluded_categories) ) {
$posts_in_ex_cats_sql = " AND tt.taxonomy = 'category' AND tt.term_id NOT IN (" . implode($excluded_categories, ',') . ')';
}
}
}
$adjacent = $previous ? 'previous' : 'next';
$op = $previous ? '<' : '>';
$order = $previous ? 'DESC' : 'ASC';
$join = apply_filters( "get_{$adjacent}_post_join", $join, $in_same_cat, $excluded_categories );
$where = apply_filters( "get_{$adjacent}_post_where", $wpdb->prepare("WHERE p.post_date $op %s AND p.post_type = %s AND p.post_status = 'publish' $posts_in_ex_cats_sql", $current_post_date, $post->post_type), $in_same_cat, $excluded_categories );
$sort = apply_filters( "get_{$adjacent}_post_sort", "ORDER BY p.post_date $order LIMIT 1" );
$query = "SELECT p.* FROM $wpdb->posts AS p $join $where $sort";
$query_key = 'adjacent_post_' . md5($query);
$result = wp_cache_get($query_key, 'counts');
if ( false !== $result )
return $result;
$result = $wpdb->get_row("SELECT p.* FROM $wpdb->posts AS p $join $where $sort");
if ( null === $result )
$result = '';
wp_cache_set($query_key, $result, 'counts');
return $result;
}
?>
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