Source

File: wp-admin/includes/post.php

function wp_edit_posts_query( $q = false ) {
	if ( false === $q ) {
		$q = $_GET;
	}
	$q['m']     = isset( $q['m'] ) ? (int) $q['m'] : 0;
	$q['cat']   = isset( $q['cat'] ) ? (int) $q['cat'] : 0;
	$post_stati = get_post_stati();

	if ( isset( $q['post_type'] ) && in_array( $q['post_type'], get_post_types(), true ) ) {
		$post_type = $q['post_type'];
	} else {
		$post_type = 'post';
	}

	$avail_post_stati = get_available_post_statuses( $post_type );
	$post_status      = '';
	$perm             = '';

	if ( isset( $q['post_status'] ) && in_array( $q['post_status'], $post_stati, true ) ) {
		$post_status = $q['post_status'];
		$perm        = 'readable';
	}

	$orderby = '';

	if ( isset( $q['orderby'] ) ) {
		$orderby = $q['orderby'];
	} elseif ( isset( $q['post_status'] ) && in_array( $q['post_status'], array( 'pending', 'draft' ), true ) ) {
		$orderby = 'modified';
	}

	$order = '';

	if ( isset( $q['order'] ) ) {
		$order = $q['order'];
	} elseif ( isset( $q['post_status'] ) && 'pending' === $q['post_status'] ) {
		$order = 'ASC';
	}

	$per_page       = "edit_{$post_type}_per_page";
	$posts_per_page = (int) get_user_option( $per_page );
	if ( empty( $posts_per_page ) || $posts_per_page < 1 ) {
		$posts_per_page = 20;
	}

	/**
	 * Filters the number of items per page to show for a specific 'per_page' type.
	 *
	 * The dynamic portion of the hook name, `$post_type`, refers to the post type.
	 *
	 * Some examples of filter hooks generated here include: 'edit_attachment_per_page',
	 * 'edit_post_per_page', 'edit_page_per_page', etc.
	 *
	 * @since 3.0.0
	 *
	 * @param int $posts_per_page Number of posts to display per page for the given post
	 *                            type. Default 20.
	 */
	$posts_per_page = apply_filters( "edit_{$post_type}_per_page", $posts_per_page );

	/**
	 * Filters the number of posts displayed per page when specifically listing "posts".
	 *
	 * @since 2.8.0
	 *
	 * @param int    $posts_per_page Number of posts to be displayed. Default 20.
	 * @param string $post_type      The post type.
	 */
	$posts_per_page = apply_filters( 'edit_posts_per_page', $posts_per_page, $post_type );

	$query = compact( 'post_type', 'post_status', 'perm', 'order', 'orderby', 'posts_per_page' );

	// Hierarchical types require special args.
	if ( is_post_type_hierarchical( $post_type ) && empty( $orderby ) ) {
		$query['orderby']                = 'menu_order title';
		$query['order']                  = 'asc';
		$query['posts_per_page']         = -1;
		$query['posts_per_archive_page'] = -1;
		$query['fields']                 = 'id=>parent';
	}

	if ( ! empty( $q['show_sticky'] ) ) {
		$query['post__in'] = (array) get_option( 'sticky_posts' );
	}

	wp( $query );

	return $avail_post_stati;
}