Log WP_Query calls

wp-query-log.php

<?php

/**
 * Wrapper around WP_Query; logs various actions.
 *
 * After writing it, I realized that it's better to just step through the code using Xdebug.
 */
class WP_Query_Log {

	private $original;

	function __construct( $wp_query ) {
		$this->original = $wp_query;
	}

	function __call( $method, $args ) {
		if ( 0 !== strpos( $method, 'is_' ) )
			self::log_call( $method, $args );

		return call_user_func_array( array( $this->original, $method ), $args );
	}

	function &__get( $key ) {
		self::log( "Getting '$key'" );

		return $this->original->$key;
	}

	function __set( $key, $value ) {
		self::log( "Setting '$key' to " . self::arg_to_str( $value ) );
		return $this->original->$key = $value;
	}

	private static function log_call( $method, $args ) {
		$arg_str = array_map( array( __CLASS__, 'arg_to_str' ), $args );
		$arg_str = empty( $args ) ? '' : ' ' . implode( ', ', $arg_str ) . ' ';

		echo self::log( "Calling $method($arg_str)" );
	}

	private static function arg_to_str( $arg ) {
		if ( is_array( $arg ) && empty( $arg ) )
			return 'array()';

		return var_export( $arg, true );
	}

	private static function log( $str ) {
		echo html( 'pre', $str );
	}
}

add_action( 'setup_theme', function() {
	global $wp_query;

	$wp_query = new WP_Query_Log( $wp_query );
});