<?php

/**

 * Core Metadata API

 *

 * Functions for retrieving and manipulating metadata of various WordPress object types. Metadata

 * for an object is a represented by a simple key-value pair. Objects may contain multiple

 * metadata entries that share the same key and differ only in their value.

 *

 * @package WordPress

 * @subpackage Meta

 */

/**

 * Adds metadata for the specified object.

 *

 * @since 2.9.0

 *

 * @global wpdb $wpdb WordPress database abstraction object.

 *

 * @param string $meta_type  Type of object metadata is for. Accepts 'post', 'comment', 'term', 'user',

 *                           or any other object type with an associated meta table.

 * @param int    $object_id  ID of the object metadata is for.

 * @param string $meta_key   Metadata key.

 * @param mixed  $meta_value Metadata value. Must be serializable if non-scalar.

 * @param bool   $unique     Optional. Whether the specified metadata key should be unique for the object.

 *                           If true, and the object already has a value for the specified metadata key,

 *                           no change will be made. Default false.

 * @return int|false The meta ID on success, false on failure.

 */

function add_metadata( $meta_type, $object_id, $meta_key, $meta_value, $unique = false ) {

	global $wpdb;

	if ( ! $meta_type || ! $meta_key || ! is_numeric( $object_id ) ) {

		return false;

	}

	$object_id = absint( $object_id );

	if ( ! $object_id ) {

		return false;

	}

	$table = _get_meta_table( $meta_type );

	if ( ! $table ) {

		return false;

	}

	$meta_subtype = get_object_subtype( $meta_type, $object_id );

	$column = sanitize_key( $meta_type . '_id' );

	// expected_slashed ($meta_key)

	$meta_key   = wp_unslash( $meta_key );

	$meta_value = wp_unslash( $meta_value );

	$meta_value = sanitize_meta( $meta_key, $meta_value, $meta_type, $meta_subtype );

	/**

	 * Short-circuits adding metadata of a specific type.

	 *

	 * (post, comment, term, user, or any other type with an associated meta table).

	 * Returning a non-null value will effectively short-circuit the function.

	 *

	 * @since 3.1.0

	 *

	 * @param null|bool $check      Whether to allow adding metadata for the given type.

	 * @param int       $object_id  ID of the object metadata is for.

	 * @param string    $meta_key   Metadata key.

	 * @param mixed     $meta_value Metadata value. Must be serializable if non-scalar.

	 * @param bool      $unique     Whether the specified meta key should be unique for the object.

	 */

	$check = apply_filters( "add_{$meta_type}_metadata", null, $object_id, $meta_key, $meta_value, $unique );

	if ( null !== $check ) {

		return $check;

	}

	if ( $unique && $wpdb->get_var(

		$wpdb->prepare(

			"SELECT COUNT(*) FROM $table WHERE meta_key = %s AND $column = %d",

			$meta_key,

			$object_id

		)

	) ) {

		return false;

	}

	$_meta_value = $meta_value;

	$meta_value  = maybe_serialize( $meta_value );

	/**

	 * Fires immediately before meta of a specific type is added.

	 *

	 * (post, comment, term, user, or any other type with an associated meta table).

	 *

	 * @since 3.1.0

	 *

	 * @param int    $object_id   ID of the object metadata is for.

	 * @param string $meta_key    Metadata key.

	 */

	do_action( "add_{$meta_type}_meta", $object_id, $meta_key, $_meta_value );

	$result = $wpdb->insert(

		$table,

		array(

			$column      => $object_id,

			'meta_key'   => $meta_key,

			'meta_value' => $meta_value,

		)

	);

	if ( ! $result ) {

		return false;

	}

	$mid = (int) $wpdb->insert_id;

	wp_cache_delete( $object_id, $meta_type . '_meta' );

	/**

	 * Fires immediately after meta of a specific type is added.

	 *

	 * (post, comment, term, user, or any other type with an associated meta table).

	 *

	 * @since 2.9.0

	 *

	 * @param int    $mid         The meta ID after successful update.

	 * @param int    $object_id   ID of the object metadata is for.

	 * @param string $meta_key    Metadata key.

	 */

	do_action( "added_{$meta_type}_meta", $mid, $object_id, $meta_key, $_meta_value );

	return $mid;

}

/**

 * Updates metadata for the specified object. If no value already exists for the specified object

 * ID and metadata key, the metadata will be added.

 *

 * @since 2.9.0

 *

 * @global wpdb $wpdb WordPress database abstraction object.

 *

 * @param string $meta_type  Type of object metadata is for. Accepts 'post', 'comment', 'term', 'user',

 *                           or any other object type with an associated meta table.

 * @param int    $object_id  ID of the object metadata is for.

 * @param string $meta_key   Metadata key.

 * @param mixed  $meta_value Metadata value. Must be serializable if non-scalar.

 * @param mixed  $prev_value Optional. Previous value to check before updating.

 *                           If specified, only update existing metadata entries with

 *                           this value. Otherwise, update all entries. Default empty.

 * @return int|bool The new meta field ID if a field with the given key didn't exist

 *                  and was therefore added, true on successful update,

 *                  false on failure or if the value passed to the function

 *                  is the same as the one that is already in the database.

 */

function update_metadata( $meta_type, $object_id, $meta_key, $meta_value, $prev_value = '' ) {

	global $wpdb;

	if ( ! $meta_type || ! $meta_key || ! is_numeric( $object_id ) ) {

		return false;

	}

	$object_id = absint( $object_id );

	if ( ! $object_id ) {

		return false;

	}

	$table = _get_meta_table( $meta_type );

	if ( ! $table ) {

		return false;

	}

	$meta_subtype = get_object_subtype( $meta_type, $object_id );

	$column    = sanitize_key( $meta_type . '_id' );

	$id_column = ( 'user' === $meta_type ) ? 'umeta_id' : 'meta_id';

	// expected_slashed ($meta_key)

	$raw_meta_key = $meta_key;

	$meta_key     = wp_unslash( $meta_key );

	$passed_value = $meta_value;

	$meta_value   = wp_unslash( $meta_value );

	$meta_value   = sanitize_meta( $meta_key, $meta_value, $meta_type, $meta_subtype );

	/**

	 * Short-circuits updating metadata of a specific type.

	 *

	 * (post, comment, term, user, or any other type with an associated meta table).

	 * Returning a non-null value will effectively short-circuit the function.

	 *

	 * @since 3.1.0

	 *

	 * @param null|bool $check      Whether to allow updating metadata for the given type.

	 * @param int       $object_id  ID of the object metadata is for.

	 * @param string    $meta_key   Metadata key.

	 * @param mixed     $meta_value Metadata value. Must be serializable if non-scalar.

	 * @param mixed     $prev_value Optional. Previous value to check before updating.

	 *                              If specified, only update existing metadata entries with

	 *                              this value. Otherwise, update all entries.

	 */

	$check = apply_filters( "update_{$meta_type}_metadata", null, $object_id, $meta_key, $meta_value, $prev_value );

	if ( null !== $check ) {

		return (bool) $check;

	}

	// Compare existing value to new value if no prev value given and the key exists only once.

	if ( empty( $prev_value ) ) {

		$old_value = get_metadata_raw( $meta_type, $object_id, $meta_key );

		if ( is_countable( $old_value ) && count( $old_value ) === 1 ) {

			if ( $old_value[0] === $meta_value ) {

				return false;

			}

		}

	}

	$meta_ids = $wpdb->get_col( $wpdb->prepare( "SELECT $id_column FROM $table WHERE meta_key = %s AND $column = %d", $meta_key, $object_id ) );

	if ( empty( $meta_ids ) ) {

		return add_metadata( $meta_type, $object_id, $raw_meta_key, $passed_value );

	}

	$_meta_value = $meta_value;

	$meta_value  = maybe_serialize( $meta_value );

	$data  = compact( 'meta_value' );

	$where = array(

		$column    => $object_id,

		'meta_key' => $meta_key,

	);

	if ( ! empty( $prev_value ) ) {

		$prev_value          = maybe_serialize( $prev_value );

		$where['meta_value'] = $prev_value;

	}

	foreach ( $meta_ids as $meta_id ) {

		/**

		 * Fires immediately before updating metadata of a specific type.

		 *

		 * (post, comment, term, user, or any other type with an associated meta table).

		 *

		 * @since 2.9.0

		 *

		 * @param int    $meta_id     ID of the metadata entry to update.

		 * @param int    $object_id   ID of the object metadata is for.

		 * @param string $meta_key    Metadata key.

		 */

		do_action( "update_{$meta_type}_meta", $meta_id, $object_id, $meta_key, $_meta_value );

		if ( 'post' === $meta_type ) {

			/**

			 * Fires immediately before updating a post's metadata.

			 *

			 * @since 2.9.0

			 *

			 * @param int    $meta_id    ID of metadata entry to update.

			 * @param int    $object_id  Post ID.

			 * @param string $meta_key   Metadata key.

			 * @param mixed  $meta_value Metadata value. This will be a PHP-serialized string representation of the value

			 *                           if the value is an array, an object, or itself a PHP-serialized string.

			 */

			do_action( 'update_postmeta', $meta_id, $object_id, $meta_key, $meta_value );

		}

	}

	$result = $wpdb->update( $table, $data, $where );

	if ( ! $result ) {

		return false;

	}

	wp_cache_delete( $object_id, $meta_type . '_meta' );

	foreach ( $meta_ids as $meta_id ) {

		/**

		 * Fires immediately after updating metadata of a specific type.

		 *

		 * (post, comment, term, user, or any other type with an associated meta table).

		 *

		 * @since 2.9.0

		 *

		 * @param int    $meta_id     ID of updated metadata entry.

		 * @param int    $object_id   ID of the object metadata is for.

		 * @param string $meta_key    Metadata key.

		 */

		do_action( "updated_{$meta_type}_meta", $meta_id, $object_id, $meta_key, $_meta_value );

		if ( 'post' === $meta_type ) {

			/**

			 * Fires immediately after updating a post's metadata.

			 *

			 * @since 2.9.0

			 *

			 * @param int    $meta_id    ID of updated metadata entry.

			 * @param int    $object_id  Post ID.

			 * @param string $meta_key   Metadata key.

			 * @param mixed  $meta_value Metadata value. This will be a PHP-serialized string representation of the value

			 *                           if the value is an array, an object, or itself a PHP-serialized string.

			 */

			do_action( 'updated_postmeta', $meta_id, $object_id, $meta_key, $meta_value );

		}

	}

	return true;

}

/**

 * Deletes metadata for the specified object.

 *

 * @since 2.9.0

 *

 * @global wpdb $wpdb WordPress database abstraction object.

 *

 * @param string $meta_type  Type of object metadata is for. Accepts 'post', 'comment', 'term', 'user',

 *                           or any other object type with an associated meta table.

 * @param int    $object_id  ID of the object metadata is for.

 * @param string $meta_key   Metadata key.

 * @param mixed  $meta_value Optional. Metadata value. Must be serializable if non-scalar.

 *                           If specified, only delete metadata entries with this value.

 *                           Otherwise, delete all entries with the specified meta_key.

 *                           Pass `null`, `false`, or an empty string to skip this check.

 *                           (For backward compatibility, it is not possible to pass an empty string

 *                           to delete those entries with an empty string for a value.)

 * @param bool   $delete_all Optional. If true, delete matching metadata entries for all objects,

 *                           ignoring the specified object_id. Otherwise, only delete

 *                           matching metadata entries for the specified object_id. Default false.

 * @return bool True on successful delete, false on failure.

 */

function delete_metadata( $meta_type, $object_id, $meta_key, $meta_value = '', $delete_all = false ) {

	global $wpdb;

	if ( ! $meta_type || ! $meta_key || ! is_numeric( $object_id ) && ! $delete_all ) {

		return false;

	}

	$object_id = absint( $object_id );

	if ( ! $object_id && ! $delete_all ) {

		return false;

	}

	$table = _get_meta_table( $meta_type );

	if ( ! $table ) {

		return false;

	}

	$type_column = sanitize_key( $meta_type . '_id' );

	$id_column   = ( 'user' === $meta_type ) ? 'umeta_id' : 'meta_id';

	// expected_slashed ($meta_key)

	$meta_key   = wp_unslash( $meta_key );

	$meta_value = wp_unslash( $meta_value );

	/**

	 * Short-circuits deleting metadata of a specific type.

	 *

	 * (post, comment, term, user, or any other type with an associated meta table).

	 * Returning a non-null value will effectively short-circuit the function.

	 *

	 * @since 3.1.0

	 *

	 * @param null|bool $delete     Whether to allow metadata deletion of the given type.

	 * @param int       $object_id  ID of the object metadata is for.

	 * @param string    $meta_key   Metadata key.

	 * @param mixed     $meta_value Metadata value. Must be serializable if non-scalar.

	 * @param bool      $delete_all Whether to delete the matching metadata entries

	 *                              for all objects, ignoring the specified $object_id.

	 *                              Default false.