/wp-includes/post.php

<?php
/**
 * Post functions and post utility function.
 *
 * @package WordPress
 * @subpackage Post
 * @since 1.5.0
 */

//
// Post Type Registration
//

/**
 * Creates the initial post types when 'init' action is fired.
 */
function create_initial_post_types() {
	register_post_type( 'post', array(
		'public'  => true,
		'_builtin' => true, /* internal use only. don't use this when registering your own post type. */
		'_edit_link' => 'post.php?post=%d', /* internal use only. don't use this when registering your own post type. */
		'capability_type' => 'post',
		'hierarchical' => false,
		'rewrite' => false,
		'query_var' => false,
		'supports' => array( 'title', 'editor', 'author', 'thumbnail', 'excerpt', 'trackbacks', 'custom-fields', 'comments', 'revisions' ),
	) );

	register_post_type( 'page', array(
		'public' => true,
		'_builtin' => true, /* internal use only. don't use this when registering your own post type. */
		'_edit_link' => 'post.php?post=%d', /* internal use only. don't use this when registering your own post type. */
		'capability_type' => 'page',
		'hierarchical' => true,
		'rewrite' => false,
		'query_var' => false,
		'supports' => array( 'title', 'editor', 'author', 'thumbnail', 'page-attributes', 'custom-fields', 'comments', 'revisions' ),
	) );

	register_post_type( 'attachment', array(
		'labels' => array(
			'name' => __( 'Media' ),
		),
		'public' => true,
		'show_ui' => false,
		'_builtin' => true, /* internal use only. don't use this when registering your own post type. */
		'_edit_link' => 'media.php?attachment_id=%d', /* internal use only. don't use this when registering your own post type. */
		'capability_type' => 'post',
		'hierarchical' => false,
		'rewrite' => false,
		'query_var' => false,
		'can_export' => false,
		'show_in_nav_menus' => false,
	) );

	register_post_type( 'revision', array(
		'labels' => array(
			'name' => __( 'Revisions' ),
			'singular_name' => __( 'Revision' ),
		),
		'public' => false,
		'_builtin' => true, /* internal use only. don't use this when registering your own post type. */
		'_edit_link' => 'revision.php?revision=%d', /* internal use only. don't use this when registering your own post type. */
		'capability_type' => 'post',
		'hierarchical' => false,
		'rewrite' => false,
		'query_var' => false,
	) );

	register_post_type( 'nav_menu_item', array(
		'labels' => array(
			'name' => __( 'Navigation Menu Items' ),
			'singular_name' => __( 'Navigation Menu Item' ),
		),
		'public' => false,
		'_builtin' => true, /* internal use only. don't use this when registering your own post type. */
		'capability_type' => 'post',
		'hierarchical' => false,
		'rewrite' => false,
		'query_var' => false,
	) );

	register_post_status( 'publish', array(
		'label'       => _x( 'Published', 'post' ),
		'public'      => true,
		'_builtin'    => true, /* internal use only. */
		'label_count' => _n_noop( 'Published <span class="count">(%s)</span>', 'Published <span class="count">(%s)</span>' ),
	) );

	register_post_status( 'future', array(
		'label'       => _x( 'Scheduled', 'post' ),
		'protected'   => true,
		'_builtin'    => true, /* internal use only. */
		'label_count' => _n_noop('Scheduled <span class="count">(%s)</span>', 'Scheduled <span class="count">(%s)</span>' ),
	) );

	register_post_status( 'draft', array(
		'label'       => _x( 'Draft', 'post' ),
		'protected'   => true,
		'_builtin'    => true, /* internal use only. */
		'label_count' => _n_noop( 'Draft <span class="count">(%s)</span>', 'Drafts <span class="count">(%s)</span>' ),
	) );

	register_post_status( 'pending', array(
		'label'       => _x( 'Pending', 'post' ),
		'protected'   => true,
		'_builtin'    => true, /* internal use only. */
		'label_count' => _n_noop( 'Pending <span class="count">(%s)</span>', 'Pending <span class="count">(%s)</span>' ),
	) );

	register_post_status( 'private', array(
		'label'       => _x( 'Private', 'post' ),
		'private'     => true,
		'_builtin'    => true, /* internal use only. */
		'label_count' => _n_noop( 'Private <span class="count">(%s)</span>', 'Private <span class="count">(%s)</span>' ),
	) );

	register_post_status( 'trash', array(
		'label'       => _x( 'Trash', 'post' ),
		'internal'    => true,
		'_builtin'    => true, /* internal use only. */
		'label_count' => _n_noop( 'Trash <span class="count">(%s)</span>', 'Trash <span class="count">(%s)</span>' ),
		'show_in_admin_status_list' => true,
	) );

	register_post_status( 'auto-draft', array(
		'label'    => 'auto-draft',
		'internal' => true,
		'_builtin' => true, /* internal use only. */
	) );

	register_post_status( 'inherit', array(
		'label'    => 'inherit',
		'internal' => true,
		'_builtin' => true, /* internal use only. */
		'exclude_from_search' => false,
	) );
}
add_action( 'init', 'create_initial_post_types', 0 ); // highest priority

/**
 * Retrieve attached file path based on attachment ID.
 *
 * You can optionally send it through the 'get_attached_file' filter, but by
 * default it will just return the file path unfiltered.
 *
 * The function works by getting the single post meta name, named
 * '_wp_attached_file' and returning it. This is a convenience function to
 * prevent looking up the meta name and provide a mechanism for sending the
 * attached filename through a filter.
 *
 * @since 2.0.0
 * @uses apply_filters() Calls 'get_attached_file' on file path and attachment ID.
 *
 * @param int $attachment_id Attachment ID.
 * @param bool $unfiltered Whether to apply filters.
 * @return string The file path to the attached file.
 */
function get_attached_file( $attachment_id, $unfiltered = false ) {
	$file = get_post_meta( $attachment_id, '_wp_attached_file', true );
	// If the file is relative, prepend upload dir
	if ( 0 !== strpos($file, '/') && !preg_match('|^.:\\\|', $file) && ( ($uploads = wp_upload_dir()) && false === $uploads['error'] ) )
		$file = $uploads['basedir'] . "/$file";
	if ( $unfiltered )
		return $file;
	return apply_filters( 'get_attached_file', $file, $attachment_id );
}

/**
 * Update attachment file path based on attachment ID.
 *
 * Used to update the file path of the attachment, which uses post meta name
 * '_wp_attached_file' to store the path of the attachment.
 *
 * @since 2.1.0
 * @uses apply_filters() Calls 'update_attached_file' on file path and attachment ID.
 *
 * @param int $attachment_id Attachment ID
 * @param string $file File path for the attachment
 * @return bool False on failure, true on success.
 */
function update_attached_file( $attachment_id, $file ) {
	if ( !get_post( $attachment_id ) )
		return false;

	$file = apply_filters( 'update_attached_file', $file, $attachment_id );
	$file = _wp_relative_upload_path($file);

	return update_post_meta( $attachment_id, '_wp_attached_file', $file );
}

/**
 * Return relative path to an uploaded file.
 *
 * The path is relative to the current upload dir.
 *
 * @since 2.9.0
 * @uses apply_filters() Calls '_wp_relative_upload_path' on file path.
 *
 * @param string $path Full path to the file
 * @return string relative path on success, unchanged path on failure.
 */
function _wp_relative_upload_path( $path ) {
	$new_path = $path;

	if ( ($uploads = wp_upload_dir()) && false === $uploads['error'] ) {
		if ( 0 === strpos($new_path, $uploads['basedir']) ) {
				$new_path = str_replace($uploads['basedir'], '', $new_path);
				$new_path = ltrim($new_path, '/');
		}
	}

	return apply_filters( '_wp_relative_upload_path', $new_path, $path );
}

/**
 * Retrieve all children of the post parent ID.
 *
 * Normally, without any enhancements, the children would apply to pages. In the
 * context of the inner workings of WordPress, pages, posts, and attachments
 * share the same table, so therefore the functionality could apply to any one
 * of them. It is then noted that while this function does not work on posts, it
 * does not mean that it won't work on posts. It is recommended that you know
 * what context you wish to retrieve the children of.
 *
 * Attachments may also be made the child of a post, so if that is an accurate
 * statement (which needs to be verified), it would then be possible to get
 * all of the attachments for a post. Attachments have since changed since
 * version 2.5, so this is most likely unaccurate, but serves generally as an
 * example of what is possible.
 *
 * The arguments listed as defaults are for this function and also of the
 * {@link get_posts()} function. The arguments are combined with the
 * get_children defaults and are then passed to the {@link get_posts()}
 * function, which accepts additional arguments. You can replace the defaults in
 * this function, listed below and the additional arguments listed in the
 * {@link get_posts()} function.
 *
 * The 'post_parent' is the most important argument and important attention
 * needs to be paid to the $args parameter. If you pass either an object or an
 * integer (number), then just the 'post_parent' is grabbed and everything else
 * is lost. If you don't specify any arguments, then it is assumed that you are
 * in The Loop and the post parent will be grabbed for from the current post.
 *
 * The 'post_parent' argument is the ID to get the children. The 'numberposts'
 * is the amount of posts to retrieve that has a default of '-1', which is
 * used to get all of the posts. Giving a number higher than 0 will only
 * retrieve that amount of posts.
 *
 * The 'post_type' and 'post_status' arguments can be used to choose what
 * criteria of posts to retrieve. The 'post_type' can be anything, but WordPress
 * post types are 'post', 'pages', and 'attachments'. The 'post_status'
 * argument will accept any post status within the write administration panels.
 *
 * @see get_posts() Has additional arguments that can be replaced.
 * @internal Claims made in the long description might be inaccurate.
 *
 * @since 2.0.0
 *
 * @param mixed $args Optional. User defined arguments for replacing the defaults.
 * @param string $output Optional. Constant for return type, either OBJECT (default), ARRAY_A, ARRAY_N.
 * @return array|bool False on failure and the type will be determined by $output parameter.
 */
function &get_children($args = '', $output = OBJECT) {
	$kids = array();
	if ( empty( $args ) ) {
		if ( isset( $GLOBALS['post'] ) ) {
			$args = array('post_parent' => (int) $GLOBALS['post']->post_parent );
		} else {
			return $kids;
		}
	} elseif ( is_object( $args ) ) {
		$args = array('post_parent' => (int) $args->post_parent );
	} elseif ( is_numeric( $args ) ) {
		$args = array('post_parent' => (int) $args);
	}

	$defaults = array(
		'numberposts' => -1, 'post_type' => 'any',
		'post_status' => 'any', 'post_parent' => 0,
	);

	$r = wp_parse_args( $args, $defaults );

	$children = get_posts( $r );

	if ( !$children )
		return $kids;

	update_post_cache($children);

	foreach ( $children as $key => $child )
		$kids[$child->ID] =& $children[$key];

	if ( $output == OBJECT ) {
		return $kids;
	} elseif ( $output == ARRAY_A ) {
		foreach ( (array) $kids as $kid )
			$weeuns[$kid->ID] = get_object_vars($kids[$kid->ID]);
		return $weeuns;
	} elseif ( $output == ARRAY_N ) {
		foreach ( (array) $kids as $kid )
			$babes[$kid->ID] = array_values(get_object_vars($kids[$kid->ID]));
		return $babes;
	} else {
		return $kids;
	}
}

/**
 * Get extended entry info (<!--more-->).
 *
 * There should not be any space after the second dash and before the word
 * 'more'. There can be text or space(s) after the word 'more', but won't be
 * referenced.
 *
 * The returned array has 'main' and 'extended' keys. Main has the text before
 * the <code><!--more--></code>. The 'extended' key has the content after the
 * <code><!--more--></code> comment.
 *
 * @since 1.0.0
 *
 * @param string $post Post content.
 * @return array Post before ('main') and after ('extended').
 */
function get_extended($post) {
	//Match the new style more links
	if ( preg_match('/<!--more(.*?)?-->/', $post, $matches) ) {
		list($main, $extended) = explode($matches[0], $post, 2);
	} else {
		$main = $post;
		$extended = '';
	}

	// Strip leading and trailing whitespace
	$main = preg_replace('/^[\s]*(.*)[\s]*$/', '\\1', $main);
	$extended = preg_replace('/^[\s]*(.*)[\s]*$/', '\\1', $extended);

	return array('main' => $main, 'extended' => $extended);
}

/**
 * Retrieves post data given a post ID or post object.
 *
 * See {@link sanitize_post()} for optional $filter values. Also, the parameter
 * $post, must be given as a variable, since it is passed by reference.
 *
 * @since 1.5.1
 * @uses $wpdb
 * @link http://codex.wordpress.org/Function_Reference/get_post
 *
 * @param int|object $post Post ID or post object.
 * @param string $output Optional, default is Object. Either OBJECT, ARRAY_A, or ARRAY_N.
 * @param string $filter Optional, default is raw.
 * @return mixed Post data
 */
function &get_post(&$post, $output = OBJECT, $filter = 'raw') {
	global $wpdb;
	$null = null;

	if ( empty($post) ) {
		if ( isset($GLOBALS['post']) )
			$_post = & $GLOBALS['post'];
		else
			return $null;
	} elseif ( is_object($post) && empty($post->filter) ) {
		_get_post_ancestors($post);
		$_post = sanitize_post($post, 'raw');
		wp_cache_add($post->ID, $_post, 'posts');
	} else {
		if ( is_object($post) )
			$post = $post->ID;
		$post = (int) $post;
		if ( ! $_post = wp_cache_get($post, 'posts') ) {
			$_post = $wpdb->get_row($wpdb->prepare("SELECT * FROM $wpdb->posts WHERE ID = %d LIMIT 1", $post));
			if ( ! $_post )
				return $null;
			_get_post_ancestors($_post);
			$_post = sanitize_post($_post, 'raw');
			wp_cache_add($_post->ID, $_post, 'posts');
		}
	}

	if ($filter != 'raw')
		$_post = sanitize_post($_post, $filter);

	if ( $output == OBJECT ) {
		return $_post;
	} elseif ( $output == ARRAY_A ) {
		$__post = get_object_vars($_post);
		return $__post;
	} elseif ( $output == ARRAY_N ) {
		$__post = array_values(get_object_vars($_post));
		return $__post;
	} else {
		return $_post;
	}
}

/**
 * Retrieve ancestors of a post.
 *
 * @since 2.5.0
 *
 * @param int|object $post Post ID or post object
 * @return array Ancestor IDs or empty array if none are found.
 */
function get_post_ancestors($post) {
	$post = get_post($post);

	if ( !empty($post->ancestors) )
		return $post->ancestors;

	return array();
}

/**
 * Retrieve data from a post field based on Post ID.
 *
 * Examples of the post field will be, 'post_type', 'post_status', 'content',
 * etc and based off of the post object property or key names.
 *
 * The context values are based off of the taxonomy filter functions and
 * supported values are found within those functions.
 *
 * @since 2.3.0
 * @uses sanitize_post_field() See for possible $context values.
 *
 * @param string $field Post field name
 * @param id $post Post ID
 * @param string $context Optional. How to filter the field. Default is display.
 * @return WP_Error|string Value in post field or WP_Error on failure
 */
function get_post_field( $field, $post, $context = 'display' ) {
	$post = (int) $post;
	$post = get_post( $post );

	if ( is_wp_error($post) )
		return $post;

	if ( !is_object($post) )
		return '';

	if ( !isset($post->$field) )
		return '';

	return sanitize_post_field($field, $post->$field, $post->ID, $context);
}

/**
 * Retrieve the mime type of an attachment based on the ID.
 *
 * This function can be used with any post type, but it makes more sense with
 * attachments.
 *
 * @since 2.0.0
 *
 * @param int $ID Optional. Post ID.
 * @return bool|string False on failure or returns the mime type
 */
function get_post_mime_type($ID = '') {
	$post = & get_post($ID);

	if ( is_object($post) )
		return $post->post_mime_type;

	return false;
}

/**
 * Retrieve the post status based on the Post ID.
 *
 * If the post ID is of an attachment, then the parent post status will be given
 * instead.
 *
 * @since 2.0.0
 *
 * @param int $ID Post ID
 * @return string|bool Post status or false on failure.
 */
function get_post_status($ID = '') {
	$post = get_post($ID);

	if ( !is_object($post) )
		return false;

	// Unattached attachments are assumed to be published.
	if ( ('attachment' == $post->post_type) && ('inherit' == $post->post_status) && ( 0 == $post->post_parent) )
		return 'publish';

	if ( ('attachment' == $post->post_type) && $post->post_parent && ($post->ID != $post->post_parent) )
		return get_post_status($post->post_parent);

	return $post->post_status;
}

/**
 * Retrieve all of the WordPress supported post statuses.
 *
 * Posts have a limited set of valid status values, this provides the
 * post_status values and descriptions.
 *
 * @since 2.5.0
 *
 * @return array List of post statuses.
 */
function get_post_statuses( ) {
	$status = array(
		'draft'			=> __('Draft'),
		'pending'		=> __('Pending Review'),
		'private'		=> __('Private'),
		'publish'		=> __('Published')
	);

	return $status;
}

/**
 * Retrieve all of the WordPress support page statuses.
 *
 * Pages have a limited set of valid status values, this provides the
 * post_status values and descriptions.
 *
 * @since 2.5.0
 *
 * @return array List of page statuses.
 */
function get_page_statuses( ) {
	$status = array(
		'draft'			=> __('Draft'),
		'private'		=> __('Private'),
		'publish'		=> __('Published')
	);

	return $status;
}

/**
 * Register a post type. Do not use before init.
 *
 * A simple function for creating or modifying a post status based on the
 * parameters given. The function will accept an array (second optional
 * parameter), along with a string for the post status name.
 *
 *
 * Optional $args contents:
 *
 * label - A descriptive name for the post status marked for translation. Defaults to $post_status.
 * public - Whether posts of this status should be shown in the admin UI. Defaults to true.
 * exclude_from_search - Whether to exclude posts with this post status from search results. Defaults to true.
 *
 * @package WordPress
 * @subpackage Post
 * @since 3.0.0
 * @uses $wp_post_statuses Inserts new post status object into the list
 *
 * @param string $post_status Name of the post status.
 * @param array|string $args See above description.
 */
function register_post_status($post_status, $args = array()) {
	global $wp_post_statuses;

	if (!is_array($wp_post_statuses))
		$wp_post_statuses = array();

	// Args prefixed with an underscore are reserved for internal use.
	$defaults = array('label' => false, 'label_count' => false, 'exclude_from_search' => null, '_builtin' => false, '_edit_link' => 'post.php?post=%d', 'capability_type' => 'post', 'hierarchical' => false, 'public' => null, 'internal' => null, 'protected' => null, 'private' => null, 'show_in_admin_all' => null, 'publicly_queryable' => null, 'show_in_admin_status_list' => null, 'show_in_admin_all_list' => null, 'single_view_cap' => null);
	$args = wp_parse_args($args, $defaults);
	$args = (object) $args;

	$post_status = sanitize_user($post_status, true);
	$args->name = $post_status;

	if ( null === $args->public && null === $args->internal && null === $args->protected && null === $args->private )
		$args->internal = true;

	if ( null === $args->public  )
		$args->public = false;

	if ( null === $args->private  )
		$args->private = false;

	if ( null === $args->protected  )
		$args->protected = false;

	if ( null === $args->internal  )
		$args->internal = false;

	if ( null === $args->publicly_queryable )
		$args->publicly_queryable = $args->public;

	if ( null === $args->exclude_from_search )
		$args->exclude_from_search = $args->internal;

	if ( null === $args->show_in_admin_all_list )
		$args->show_in_admin_all_list = !$args->internal;

	if ( null === $args->show_in_admin_status_list )
			$args->show_in_admin_status_list = !$args->internal;

	if ( null === $args->single_view_cap )
		$args->single_view_cap = $args->public ? '' : 'edit';

	if ( false === $args->label )
		$args->label = $post_status;

	if ( false === $args->label_count )
		$args->label_count = array( $args->label, $args->label );

	$wp_post_statuses[$post_status] = $args;

	return $args;
}

/**
 * Retrieve a post status object by name
 *
 * @package WordPress
 * @subpackage Post
 * @since 3.0.0
 * @uses $wp_post_statuses
 * @see register_post_status
 * @see get_post_statuses
 *
 * @param string $post_type The name of a registered post status
 * @return object A post status object
 */
function get_post_status_object( $post_status ) {
	global $wp_post_statuses;

	if ( empty($wp_post_statuses[$post_status]) )
		return null;

	return $wp_post_statuses[$post_status];
}

/**
 * Get a list of all registered post status objects.
 *
 * @package WordPress
 * @subpackage Post
 * @since 3.0.0
 * @uses $wp_post_statuses
 * @see register_post_status
 * @see get_post_status_object
 *
 * @param array|string $args An array of key => value arguments to match against the post status objects.
 * @param string $output The type of output to return, either post status 'names' or 'objects'. 'names' is the default.
 * @param string $operator The logical operation to perform. 'or' means only one element
 *  from the array needs to match; 'and' means all elements must match. The default is 'and'.
 * @return array A list of post type names or objects
 */
function get_post_stati( $args = array(), $output = 'names', $operator = 'and' ) {
	global $wp_post_statuses;

	$field = ('names' == $output) ? 'name' : false;

	return wp_filter_object_list($wp_post_statuses, $args, $operator, $field);
}

/**
 * Whether the post type is hierarchical.
 *
 * A false return value might also mean that the post type does not exist.
 *
 * @since 3.0.0
 * @see get_post_type_object
 *
 * @param string $post Post type name
 * @return bool Whether post type is hierarchical.
 */
function is_post_type_hierarchical( $post_type ) {
	if ( ! is_post_type( $post_type ) )
		return false;

	$post_type = get_post_type_object( $post_type );
	return $post_type->hierarchical;
}

/**
 * Checks if a post type is registered.
 *
 * @since 3.0.0
 * @uses get_post_type()
 *
 * @param string Post type name
 * @return bool Whether post type is registered.
 */
function is_post_type( $post_type ) {
	return (bool) get_post_type_object( $post_type );
}

/**
 * Retrieve the post type of the current post or of a given post.
 *
 * @since 2.1.0
 *
 * @uses $post The Loop current post global
 *
 * @param mixed $the_post Optional. Post object or post ID.
 * @return bool|string post type or false on failure.
 */
function get_post_type( $the_post = false ) {
	global $post;

	if ( false === $the_post )
		$the_post = $post;
	elseif ( is_numeric($the_post) )
		$the_post = get_post($the_post);

	if ( is_object($the_post) )
		return $the_post->post_type;

	return false;
}

/**
 * Retrieve a post type object by name
 *
 * @package WordPress
 * @subpackage Post
 * @since 3.0.0
 * @uses $wp_post_types
 * @see register_post_type
 * @see get_post_types
 *
 * @param string $post_type The name of a registered post type
 * @return object A post type object
 */
function get_post_type_object( $post_type ) {
	global $wp_post_types;

	if ( empty($wp_post_types[$post_type]) )
		return null;

	return $wp_post_types[$post_type];
}

/**
 * Get a list of all registered post type objects.
 *
 * @package WordPress
 * @subpackage Post
 * @since 2.9.0
 * @uses $wp_post_types
 * @see register_post_type
 *
 * @param array|string $args An array of key => value arguments to match against the post type objects.
 * @param string $output The type of output to return, either post type 'names' or 'objects'. 'names' is the default.
 * @param string $operator The logical operation to perform. 'or' means only one element
 *  from the array needs to match; 'and' means all elements must match. The default is 'and'.
 * @return array A list of post type names or objects
 */
function get_post_types( $args = array(), $output = 'names', $operator = 'and' ) {
	global $wp_post_types;

	$field = ('names' == $output) ? 'name' : false;

	return wp_filter_object_list($wp_post_types, $args, $operator, $field);
}

/**
 * Register a post type. Do not use before init.
 *
 * A simple function for creating or modifying a post type based on the
 * parameters given. The function will accept an array (second optional
 * parameter), along with a string for the post type name.
 *
 *
 * Optional $args contents:
 *
 * - label - Name of the post type shown in the menu. Usually plural. If not set, labels['name'] will be used.
 * - description - A short descriptive summary of what the post type is. Defaults to blank.
 * - public - Whether posts of this type should be shown in the admin UI. Defaults to false.
 * - exclude_from_search - Whether to exclude posts with this post type from search results. Defaults to true if the type is not public, false if the type is public.
 * - publicly_queryable - Whether post_type queries can be performed from the front page.  Defaults to whatever public is set as.
 * - show_ui - Whether to generate a default UI for managing this post type. Defaults to true if the type is public, false if the type is not public.
 * - menu_position - The position in the menu order the post type should appear. Defaults to the bottom.
 * - menu_icon - The url to the icon to be used for this menu. Defaults to use the posts icon.
 * - capability_type - The post type to use for checking read, edit, and delete capabilities. Defaults to "post".
 * - capabilities - Array of capabilities for this post type. You can see accepted values in {@link get_post_type_capabilities()}. By default the capability_type is used to construct capabilities.
 * - hierarchical - Whether the post type is hierarchical. Defaults to false.
 * - supports - An alias for calling add_post_type_support() directly. See add_post_type_support() for Documentation. Defaults to none.
 * - register_meta_box_cb - Provide a callback function that will be called when setting up the meta boxes for the edit form.  Do remove_meta_box() and add_meta_box() calls in the callback.
 * - taxonomies - An array of taxonomy identifiers that will be registered for the post type.  Default is no taxonomies. Taxonomies can be registered later with register_taxonomy() or register_taxonomy_for_object_type().
 * - labels - An array of labels for this post type. You can see accepted values in {@link get_post_type_labels()}. By default post labels are used for non-hierarchical types and page labels for hierarchical ones.
 * - permalink_epmask - The default rewrite endpoint bitmasks.
 * - rewrite - false to prevent rewrite, or array('slug'=>$slug) to customize permastruct; default will use $taxonomy as slug.
 * - query_var - false to prevent queries, or string to value of the query var to use for this post type
 * - can_export - true allows this post type to be exported.
 * - show_in_nav_menus - true makes this post type available for selection in navigation menus.
 * - _builtin - true if this post type is a native or "built-in" post_type.  THIS IS FOR INTERNAL USE ONLY!
 * - _edit_link - URL segement to use for edit link of this post type.  Set to 'post.php?post=%d'.  THIS IS FOR INTERNAL USE ONLY!
 *
 * @since 2.9.0
 * @uses $wp_post_types Inserts new post type object into the list
 *
 * @param string $post_type Name of the post type.
 * @param array|string $args See above description.
 * @return object the registered post type object
 */
function register_post_type($post_type, $args = array()) {
	global $wp_post_types, $wp_rewrite, $wp;

	if ( !is_array($wp_post_types) )
		$wp_post_types = array();

	// Args prefixed with an underscore are reserved for internal use.
	$defaults = array(
		'labels' => array(), 'description' => '', 'publicly_queryable' => null, 'exclude_from_search' => null,
		'_builtin' => false, '_edit_link' => 'post.php?post=%d', 'capability_type' => 'post', 'capabilities' => array(), 'hierarchical' => false,
		'public' => false, 'rewrite' => true, 'query_var' => true, 'supports' => array(), 'register_meta_box_cb' => null,
		'taxonomies' => array(), 'show_ui' => null, 'menu_position' => null, 'menu_icon' => null,
		'permalink_epmask' => EP_PERMALINK, 'can_export' => true, 'show_in_nav_menus' => null
	);
	$args = wp_parse_args($args, $defaults);
	$args = (object) $args;

	$post_type = sanitize_user($post_type, true);
	$args->name = $post_type;

	// If not set, default to the setting for public.
	if ( null === $args->publicly_queryable )
		$args->publicly_queryable = $args->public;

	// If not set, default to the setting for public.
	if ( null === $args->show_ui )
		$args->show_ui = $args->public;

	// Whether to show this type in nav-menus.php.  Defaults to the setting for public.
	if ( null === $args->show_in_nav_menus )
		$args->show_in_nav_menus = $args->public;

	// If not set, default to true if not public, false if public.
	if ( null === $args->exclude_from_search )
		$args->exclude_from_search = !$args->public;

	if ( empty($args->capability_type) )
		$args->capability_type = 'post';

	$args->cap = get_post_type_capabilities( $args );
	unset($args->capabilities);

	if ( ! empty($args->supports) ) {
		add_post_type_support($post_type, $args->supports);
		unset($args->supports);
	} else {
		// Add default features
		add_post_type_support($post_type, array('title', 'editor'));
	}

	if ( false !== $args->query_var && !empty($wp) ) {
		if ( true === $args->query_var )
			$args->query_var = $post_type;
		$args->query_var = sanitize_title_with_dashes($args->query_var);
		$wp->add_query_var($args->query_var);
	}

	if ( false !== $args->rewrite && '' != get_option('permalink_structure') ) {
		if ( !is_array($args->rewrite) )
			$args->rewrite = array();
		if ( !isset($args->rewrite['slug']) )
			$args->rewrite['slug'] = $post_type;
		if ( !isset($args->rewrite['with_front']) )
			$args->rewrite['with_front'] = true;
		if ( $args->hierarchical )
			$wp_rewrite->add_rewrite_tag("%$post_type%", '(.+?)', $args->query_var ? "{$args->query_var}=" : "post_type=$post_type&name=");
		else
			$wp_rewrite->add_rewrite_tag("%$post_type%", '([^/]+)', $args->query_var ? "{$args->query_var}=" : "post_type=$post_type&name=");
		$wp_rewrite->add_permastruct($post_type, "{$args->rewrite['slug']}/%$post_type%", $args->rewrite['with_front'], $args->permalink_epmask);
	}

	if ( $args->register_meta_box_cb )
		add_action('add_meta_boxes_' . $post_type, $args->register_meta_box_cb, 10, 1);

	$args->labels = get_post_type_labels( $args );
	$args->label = $args->labels->name;

	$wp_post_types[$post_type] = $args;

	add_action( 'future_' . $post_type, '_future_post_hook', 5, 2 );

	foreach ( $args->taxonomies as $taxonomy ) {
		register_taxonomy_for_object_type( $taxonomy, $post_type );
	}

	return $args;
}

/**
 * Builds an object with all post type capabilities out of a post type object
 *
 * Accepted keys of the capabilities array in the post type object:
 * - edit_post - The meta capability that controls editing a particular object of this post type. Defaults to "edit_ . $capability_type" (edit_post).
 * - edit_posts - The capability that controls editing objects of this post type as a class. Defaults to "edit_ . $capability_type . s" (edit_posts).
 * - edit_others_posts - The capability that controls editing objects of this post type that are owned by other users. Defaults to "edit_others_ . $capability_type . s" (edit_others_posts).
 * - publish_posts - The capability that controls publishing objects of this post type. Defaults to "publish_ . $capability_type . s" (publish_posts).
 * - read_post - The meta capability that controls reading a particular object of this post type. Defaults to "read_ . $capability_type" (read_post).
 * - read_private_posts - The capability that controls reading private posts. Defaults to "read_private . $capability_type . s" (read_private_posts).
 * - delete_post - The meta capability that controls deleting a particular object of this post type. Defaults to "delete_ . $capability_type" (delete_post).
 *
 * @since 3.0.0
 * @param object $args
 * @return object object with all the capabilities as member variables
 */
function get_post_type_capabilities( $args ) {
	$defaults = array(
		'edit_post'          => 'edit_'         . $args->capability_type,
		'edit_posts'         => 'edit_'         . $args->capability_type . 's',
		'edit_others_posts'  => 'edit_others_'  . $args->capability_type . 's',
		'publish_posts'      => 'publish_'      . $args->capability_type . 's',
		'read_post'          => 'read_'         . $args->capability_type,
		'read_private_posts' => 'read_private_' . $args->capability_type . 's',
		'delete_post'        => 'delete_'       . $args->capability_type,
	);
	$labels = array_merge( $defaults, $args->capabilities );
	return (object) $labels;
}

/**
 * Builds an object with all post type labels out of a post type object
 *
 * Accepted keys of the label array in the post type object:
 * - name - general name for the post type, usually plural. The same and overriden by $post_type_object->label. Default is Posts/Pages
 * - singular_name - name for one object of this post type. Default is Post/Page
 * - add_new - Default is Add New for both hierarchical and non-hierarchical types. When internationalizing this string, please use a {@link http://codex.wordpress.org/I18n_for_WordPress_Developers#Disambiguation_by_context gettext context} matching your post type. Example: <code>_x('Add New', 'product');</code>
 * - add_new_item - Default is Add New Post/Add New Page
 * - edit_item - Default is Edit Post/Edit Page
 * - new_item - Default is New Post/New Page
 * - view_item - Default is View Post/View Page
 * - search_items - Default is Search Posts/Search Pages
 * - not_found - Default is No posts found/No pages found
 * - not_found_in_trash - Default is No posts found in Trash/No pages found in Trash
 * - parent_item_colon - This string isn't used on non-hierarchical types. In hierarchical ones the default is Parent Page:
 *
 * Above, the first default value is for non-hierarchical post types (like posts) and the second one is for hierarchical post types (like pages.)
 *
 * @since 3.0.0
 * @param object $post_type_object
 * @return object object with all the labels as member variables
 */
function get_post_type_labels( $post_type_object ) {
	$nohier_vs_hier_defaults = array(
		'name' => array( _x('Posts', 'post type general name'), _x('Pages', 'post type general name') ),
		'singular_name' => array( _x('Post', 'post type singular name'), _x('Page', 'post type singular name') ),
		'add_new' => array( _x('Add New', 'post'), _x('Add New', 'page') ),
		'add_new_item' => array( __('Add New Post'), __('Add New Page') ),
		'edit_item' => array( __('Edit Post'), __('Edit Page') ),
		'new_item' => array( __('New Post'), __('New Page') ),
		'view_item' => array( __('View Post'), __('View Page') ),
		'search_items' => array( __('Search Posts'), __('Search Pages') ),
		'not_found' => array( __('No posts found'), __('No pages found') ),
		'not_found_in_trash' => array( __('No posts found in Trash'), __('No pages found in Trash') ),
		'parent_item_colon' => array( null, __('Parent Page:') )
	);
	return _get_custom_object_labels( $post_type_object, $nohier_vs_hier_defaults );
}

/**
 * Builds an object with custom-something object (post type, taxonomy) labels out of a custom-something object
 *
 * @access private
 */
function _get_custom_object_labels( $object, $nohier_vs_hier_defaults ) {

	if ( isset( $object->label ) ) {
		$object->labels['name'] = $object->label;
	}

	if ( !isset( $object->labels['singular_name'] ) && isset( $object->labels['name'] ) ) {
		$object->labels['singular_name'] = $object->labels['name'];
	}

	$defaults = array_map( create_function( '$x', $object->hierarchical? 'return $x[1];' : 'return $x[0];' ), $nohier_vs_hier_defaults );
	$labels = array_merge( $defaults, $object->labels );
	return (object)$labels;
}

/**
 * Register support of certain features for a post type.
 *
 * All features are directly associated with a functional area of the edit screen, such as the
 * editor or a meta box: 'title', 'editor', 'comments', 'revisions', 'trackbacks', 'author',
 * 'excerpt', 'page-attributes', 'thumbnail', and 'custom-fields'.
 *
 * Additionally, the 'revisions' feature dictates whether the post type will store revisions,
 * and the 'comments' feature dicates whether the comments count will show on the edit screen.
 *
 * @since 3.0.0
 * @param string $post_type The post type for which to add the feature
 * @param string|array $feature the feature being added, can be an array of feature strings or a single string
 */
function add_post_type_support( $post_type, $feature ) {
	global $_wp_post_type_features;

	$features = (array) $feature;
	foreach ($features as $feature) {
		if ( func_num_args() == 2 )
			$_wp_post_type_features[$post_type][$feature] = true;
		else
			$_wp_post_type_features[$post_type][$feature] = array_slice( func_get_args(), 2 );
	}
}

/**
 * Remove support for a feature from a post type.
 *
 * @since 3.0.0
 * @param string $post_type The post type for which to remove the feature
 * @param string $feature The feature being removed
 */
function remove_post_type_support( $post_type, $feature ) {
	global $_wp_post_type_features;

	if ( !isset($_wp_post_type_features[$post_type]) )
		return;

	if ( isset($_wp_post_type_features[$post_type][$feature]) )
		unset($_wp_post_type_features[$post_type][$feature]);
}

/**
 * Checks a post type's support for a given feature
 *
 * @since 3.0.0
 * @param string $post_type The post type being checked
 * @param string $feature the feature being checked
 * @return boolean
 */

function post_type_supports( $post_type, $feature ) {
	global $_wp_post_type_features;

	if ( !isset( $_wp_post_type_features[$post_type][$feature] ) )
		return false;

	// If no args passed then no extra checks need be performed
	if ( func_num_args() <= 2 )
		return true;

	// @todo Allow pluggable arg checking
	//$args = array_slice( func_get_args(), 2 );

	return true;
}

/**
 * Updates the post type for the post ID.
 *
 * The page or post cache will be cleaned for the post ID.
 *
 * @since 2.5.0
 *
 * @uses $wpdb
 *
 * @param int $post_id Post ID to change post type. Not actually optional.
 * @param string $post_type Optional, default is post. Supported values are 'post' or 'page' to
 *  name a few.
 * @return int Amount of rows changed. Should be 1 for success and 0 for failure.
 */
function set_post_type( $post_id = 0, $post_type = 'post' ) {
	global $wpdb;

	$post_type = sanitize_post_field('post_type', $post_type, $post_id, 'db');
	$return = $wpdb->update($wpdb->posts, array('post_type' => $post_type), array('ID' => $post_id) );

	if ( 'page' == $post_type )
		clean_page_cache($post_id);
	else
		clean_post_cache($post_id);

	return $return;
}

/**
 * Retrieve list of latest posts or posts matching criteria.
 *
 * The defaults are as follows:
 *     'numberposts' - Default is 5. Total number of posts to retrieve.
 *     'offset' - Default is 0. See {@link WP_Query::query()} for more.
 *     'category' - What category to pull the posts from.
 *     'orderby' - Default is 'post_date'. How to order the posts.
 *     'order' - Default is 'DESC'. The order to retrieve the posts.
 *     'include' - See {@link WP_Query::query()} for more.
 *     'exclude' - See {@link WP_Query::query()} for more.
 *     'meta_key' - See {@link WP_Query::query()} for more.
 *     'meta_value' - See {@link WP_Query::query()} for more.
 *     'post_type' - Default is 'post'. Can be 'page', or 'attachment' to name a few.
 *     'post_parent' - The parent of the post or post type.
 *     'post_status' - Default is 'published'. Post status to retrieve.
 *
 * @since 1.2.0
 * @uses $wpdb
 * @uses WP_Query::query() See for more default arguments and information.
 * @link http://codex.wordpress.org/Template_Tags/get_posts
 *
 * @param array $args Optional. Overrides defaults.
 * @return array List of posts.
 */
function get_posts($args = null) {
	$defaults = array(
		'numberposts' => 5, 'offset' => 0,
		'category' => 0, 'orderby' => 'post_date',
		'order' => 'DESC', 'include' => array(),
		'exclude' => array(), 'meta_key' => '',
		'meta_value' =>'', 'post_type' => 'post',
		'suppress_filters' => true
	);

	$r = wp_parse_args( $args, $defaults );
	if ( empty( $r['post_status'] ) )
		$r['post_status'] = ( 'attachment' == $r['post_type'] ) ? 'inherit' : 'publish';
	if ( ! empty($r['numberposts']) )
		$r['posts_per_page'] = $r['numberposts'];
	if ( ! empty($r['category']) )
		$r['cat'] = $r['category'];
	if ( ! empty($r['include']) ) {
		$incposts = wp_parse_id_list( $r['include'] );
		$r['posts_per_page'] = count($incposts);  // only the number of posts included
		$r['post__in'] = $incposts;
	} elseif ( ! empty($r['exclude']) )
		$r['post__not_in'] = wp_parse_id_list( $r['exclude'] );

	$r['caller_get_posts'] = true;

	$get_posts = new WP_Query;
	return $get_posts->query($r);

}

//
// Post meta functions
//

/**
 * Add meta data field to a post.
 *
 * Post meta data is called "Custom Fields" on the Administration Panels.
 *
 * @since 1.5.0
 * @uses $wpdb
 * @link http://codex.wordpress.org/Function_Reference/add_post_meta
 *
 * @param int $post_id Post ID.
 * @param string $key Metadata name.
 * @param mixed $value Metadata value.
 * @param bool $unique Optional, default is false. Whether the same key should not be added.
 * @return bool False for failure. True for success.
 */
function add_post_meta($post_id, $meta_key, $meta_value, $unique = false) {
	// make sure meta is added to the post, not a revision
	if ( $the_post = wp_is_post_revision($post_id) )
		$post_id = $the_post;

	return add_metadata('post', $post_id, $meta_key, $meta_value, $unique);
}

/**
 * Remove metadata matching criteria from a post.
 *
 * You can match based on the key, or key and value. Removing based on key and
 * value, will keep from removing duplicate metadata with the same key. It also
 * allows removing all metadata matching key, if needed.
 *
 * @since 1.5.0
 * @uses $wpdb
 * @link http://codex.wordpress.org/Function_Reference/delete_post_meta
 *
 * @param int $post_id post ID
 * @param string $meta_key Metadata name.
 * @param mixed $meta_value Optional. Metadata value.
 * @return bool False for failure. True for success.
 */
function delete_post_meta($post_id, $meta_key, $meta_value = '') {
	// make sure meta is added to the post, not a revision
	if ( $the_post = wp_is_post_revision($post_id) )
		$post_id = $the_post;

	return delete_metadata('post', $post_id, $meta_key, $meta_value);
}

/**
 * Retrieve post meta field for a post.
 *
 * @since 1.5.0
 * @uses $wpdb
 * @link http://codex.wordpress.org/Function_Reference/get_post_meta
 *
 * @param int $post_id Post ID.
 * @param string $key The meta key to retrieve.
 * @param bool $single Whether to return a single value.
 * @return mixed Will be an array if $single is false. Will be value of meta data field if $single
 *  is true.
 */
function get_post_meta($post_id, $key, $single = false) {
	return get_metadata('post', $post_id, $key, $single);
}

/**
 * Update post meta field based on post ID.
 *
 * Use the $prev_value parameter to differentiate between meta fields with the
 * same key and post ID.
 *
 * If the meta field for the post does not exist, it will be added.
 *
 * @since 1.5
 * @uses $wpdb
 * @link http://codex.wordpress.org/Function_Reference/update_post_meta
 *
 * @param int $post_id Post ID.
 * @param string $key Metadata key.
 * @param mixed $value Metadata value.
 * @param mixed $prev_value Optional. Previous value to check before removing.
 * @return bool False on failure, true if success.
 */
function update_post_meta($post_id, $meta_key, $meta_value, $prev_value = '') {
	// make sure meta is added to the post, not a revision
	if ( $the_post = wp_is_post_revision($post_id) )
		$post_id = $the_post;

	return update_metadata('post', $post_id, $meta_key, $meta_value, $prev_value);
}

/**
 * Delete everything from post meta matching meta key.
 *
 * @since 2.3.0
 * @uses $wpdb
 *
 * @param string $post_meta_key Key to search for when deleting.
 * @return bool Whether the post meta key was deleted from the database
 */
function delete_post_meta_by_key($post_meta_key) {
	if ( !$post_meta_key )
		return false;

	global $wpdb;
	$post_ids = $wpdb->get_col($wpdb->prepare("SELECT DISTINCT post_id FROM $wpdb->postmeta WHERE meta_key = %s", $post_meta_key));
	if ( $post_ids ) {
		$postmetaids = $wpdb->get_col( $wpdb->prepare( "SELECT meta_id FROM $wpdb->postmeta WHERE meta_key = %s", $post_meta_key ) );
		$in = implode( ',', array_fill(1, count($postmetaids), '%d'));
		do_action( 'delete_postmeta', $postmetaids );
		$wpdb->query( $wpdb->prepare("DELETE FROM $wpdb->postmeta WHERE meta_id IN($in)", $postmetaids ));
		do_action( 'deleted_postmeta', $postmetaids );
		foreach ( $post_ids as $post_id )
			wp_cache_delete($post_id, 'post_meta');
		return true;
	}
	return false;
}

/**
 * Retrieve post meta fields, based on post ID.
 *
 * The post meta fields are retrieved from the cache, so the function is
 * optimized to be called more than once. It also applies to the functions, that
 * use this function.
 *
 * @since 1.2.0
 * @link http://codex.wordpress.org/Function_Reference/get_post_custom
 *
 * @uses $id Current Loop Post ID
 *
 * @param int $post_id post ID
 * @return array
 */
function get_post_custom($post_id = 0) {
	global $id;

	if ( !$post_id )
		$post_id = (int) $id;

	$post_id = (int) $post_id;

	if ( ! wp_cache_get($post_id, 'post_meta') )
		update_postmeta_cache($post_id);

	return wp_cache_get($post_id, 'post_meta');
}

/**
 * Retrieve meta field names for a post.
 *
 * If there are no meta fields, then nothing (null) will be returned.
 *
 * @since 1.2.0
 * @link http://codex.wordpress.org/Function_Reference/get_post_custom_keys
 *
 * @param int $post_id post ID
 * @return array|null Either array of the keys, or null if keys could not be retrieved.
 */
function get_post_custom_keys( $post_id = 0 ) {
	$custom = get_post_custom( $post_id );

	if ( !is_array($custom) )
		return;

	if ( $keys = array_keys($custom) )
		return $keys;
}

/**
 * Retrieve values for a custom post field.
 *
 * The parameters must not be considered optional. All of the post meta fields
 * will be retrieved and only the meta field key values returned.
 *
 * @since 1.2.0
 * @link http://codex.wordpress.org/Function_Reference/get_post_custom_values
 *
 * @param string $key Meta field key.
 * @param int $post_id Post ID
 * @return array Meta field values.
 */
function get_post_custom_values( $key = '', $post_id = 0 ) {
	if ( !$key )
		return null;

	$custom = get_post_custom($post_id);

	return isset($custom[$key]) ? $custom[$key] : null;
}

/**
 * Check if post is sticky.
 *
 * Sticky posts should remain at the top of The Loop. If the post ID is not
 * given, then The Loop ID for the current post will be used.
 *
 * @since 2.7.0
 *
 * @param int $post_id Optional. Post ID.
 * @return bool Whether post is sticky.
 */
function is_sticky($post_id = null) {
	global $id;

	$post_id = absint($post_id);

	if ( !$post_id )
		$post_id = absint($id);

	$stickies = get_option('sticky_posts');

	if ( !is_array($stickies) )
		return false;

	if ( in_array($post_id, $stickies) )
		return true;

	return false;
}

/**
 * Sanitize every post field.
 *
 * If the context is 'raw', then the post object or array will get minimal santization of the int fields.
 *
 * @since 2.3.0
 * @uses sanitize_post_field() Used to sanitize the fields.
 *
 * @param object|array $post The Post Object or Array
 * @param string $context Optional, default is 'display'. How to sanitize post fields.
 * @return object|array The now sanitized Post Object or Array (will be the same type as $post)
 */
function sanitize_post($post, $context = 'display') {
	if ( is_object($post) ) {
		// Check if post already filtered for this context
		if ( isset($post->filter) && $context == $post->filter )
			return $post;
		if ( !isset($post->ID) )
			$post->ID = 0;
		foreach ( array_keys(get_object_vars($post)) as $field )
			$post->$field = sanitize_post_field($field, $post->$field, $post->ID, $context);
		$post->filter = $context;
	} else {
		// Check if post already filtered for this context
		if ( isset($post['filter']) && $context == $post['filter'] )
			return $post;
		if ( !isset($post['ID']) )
			$post['ID'] = 0;
		foreach ( array_keys($post) as $field )
			$post[$field] = sanitize_post_field($field, $post[$field], $post['ID'], $context);
		$post['filter'] = $context;
	}
	return $post;
}

/**
 * Sanitize post field based on context.
 *
 * Possible context values are:  'raw', 'edit', 'db', 'display', 'attribute' and 'js'. The
 * 'display' context is used by default. 'attribute' and 'js' contexts are treated like 'display'
 * when calling filters.
 *
 * @since 2.3.0
 * @uses apply_filters() Calls 'edit_$field' and '${field_no_prefix}_edit_pre' passing $value and
 *  $post_id if $context == 'edit' and field name prefix == 'post_'.
 *
 * @uses apply_filters() Calls 'edit_post_$field' passing $value and $post_id if $context == 'db'.
 * @uses apply_filters() Calls 'pre_$field' passing $value if $context == 'db' and field name prefix == 'post_'.
 * @uses apply_filters() Calls '${field}_pre' passing $value if $context == 'db' and field name prefix != 'post_'.
 *
 * @uses apply_filters() Calls '$field' passing $value, $post_id and $context if $context == anything
 *  other than 'raw', 'edit' and 'db' and field name prefix == 'post_'.
 * @uses apply_filters() Calls 'post_$field' passing $value if $context == anything other than 'raw',
 *  'edit' and 'db' and field name prefix != 'post_'.
 *
 * @param string $field The Post Object field name.
 * @param mixed $value The Post Object value.
 * @param int $post_id Post ID.
 * @param string $context How to sanitize post fields. Looks for 'raw', 'edit', 'db', 'display',
 *               'attribute' and 'js'.
 * @return mixed Sanitized value.
 */
function sanitize_post_field($field, $value, $post_id, $context) {
	$int_fields = array('ID', 'post_parent', 'menu_order');
	if (