miss_ajax',
				'php_requests_pagecache_miss_api_call',
				'php_requests_pagecache_miss_configuration',
				'php_requests_pagecache_miss_fill',
				'php_requests_pagecache_miss_logged_in',
				'php_requests_pagecache_miss_mfunc',
				'php_requests_pagecache_miss_query_string',
				'php_requests_pagecache_miss_third_party',
				'php_requests_pagecache_miss_wp_admin',
				'pagecache_requests_time_10ms',
			)
		);
	}

	/**
	 * Usage Statisitcs sources filter.
	 *
	 * @param array $sources Sources.
	 *
	 * @return array
	 */
	public function w3tc_usage_statistics_sources( $sources ) {
		$c = Dispatcher::config();
		if ( 'apc' === $c->get_string( 'pgcache.engine' ) ) {
			$sources['apc_servers']['pgcache'] = array(
				'name' => __( 'Page Cache', 'w3-total-cache' ),
			);
		} elseif ( 'memcached' === $c->get_string( 'pgcache.engine' ) ) {
			$sources['memcached_servers']['pgcache'] = array(
				'servers'         => $c->get_array( 'pgcache.memcached.servers' ),
				'username'        => $c->get_string( 'pgcache.memcached.username' ),
				'password'        => $c->get_string( 'pgcache.memcached.password' ),
				'binary_protocol' => $c->get_boolean( 'pgcache.memcached.binary_protocol' ),
				'name'            => __( 'Page Cache', 'w3-total-cache' ),
			);
		} elseif ( 'redis' === $c->get_string( 'pgcache.engine' ) ) {
			$sources['redis_servers']['pgcache'] = array(
				'servers'                 => $c->get_array( 'pgcache.redis.servers' ),
				'verify_tls_certificates' => $c->get_boolean( 'pgcache.redis.verify_tls_certificates' ),
				'dbid'                    => $c->get_integer( 'pgcache.redis.dbid' ),
				'password'                => $c->get_string( 'pgcache.redis.password' ),
				'name'                    => __( 'Page Cache', 'w3-total-cache' ),
			);
		}

		return $sources;
	}

	/**
	 * Setup admin menu elements
	 *
	 * @param array $menu_items Menu items.
	 */
	public function w3tc_admin_bar_menu( $menu_items ) {
		$menu_items['20110.pagecache'] = array(
			'id'     => 'w3tc_flush_pgcache',
			'parent' => 'w3tc_flush',
			'title'  => __( 'Page Cache', 'w3-total-cache' ),
			'href'   => wp_nonce_url( admin_url( 'admin.php?page=w3tc_dashboard&w3tc_flush_pgcache' ), 'w3tc' ),
		);

		if ( Util_Environment::detect_post_id() && ( ! defined( 'DOING_AJAX' ) || ! DOING_AJAX ) ) {
			$menu_items['20120.pagecache'] = array(
				'id'     => 'w3tc_pgcache_flush_post',
				'parent' => 'w3tc_flush',
				'title'  => __( 'Page Cache: Current Page', 'w3-total-cache' ),
				'href'   => wp_nonce_url(
					admin_url(
						'admin.php?page=w3tc_dashboard&w3tc_flush_post&post_id=' .
							Util_Environment::detect_post_id() . '&force=true'
					),
					'w3tc'
				),
			);
		}

		return $menu_items;
	}

	/**
	 * Flush cache group.
	 *
	 * @param string $group Group name.
	 * @param array  $extras Additionals to flush.
	 */
	public function w3tc_flush_group( $group, $extras = array() ) {
		if ( isset( $extras['only'] ) && 'pagecache' !== (string) $extras['only'] ) {
			return;
		}

		$pgcacheflush = Dispatcher::component( 'PgCache_Flush' );
		$v            = $pgcacheflush->flush_group( $group );

		return $v;
	}

	/**
	 * Flushes all caches
	 *
	 * @param array $extras Additionals to flush.
	 *
	 * @return boolean
	 */
	public function w3tc_flush_posts( $extras = array() ) {
		if ( isset( $extras['only'] ) && 'pagecache' !== (string) $extras['only'] ) {
			return;
		}

		$pgcacheflush = Dispatcher::component( 'PgCache_Flush' );
		$v            = $pgcacheflush->flush();

		return $v;
	}

	/**
	 * Flushes post cache
	 *
	 * @param integer $post_id Post ID.
	 * @param boolean $force   Force flag (optional).
	 *
	 * @return boolean
	 */
	public function w3tc_flush_post( $post_id, $force = false ) {
		$pgcacheflush = Dispatcher::component( 'PgCache_Flush' );
		$v            = $pgcacheflush->flush_post( $post_id, $force );

		return $v;
	}

	/**
	 * Flushes post cache
	 *
	 * @param string $url URL.
	 *
	 * @return boolean
	 */
	public function w3tc_flush_url( $url ) {
		$pgcacheflush = Dispatcher::component( 'PgCache_Flush' );
		$v            = $pgcacheflush->flush_url( $url );

		return $v;
	}



	/**
	 * By default headers are not cached by file_generic
	 *
	 * @param mixed  $header New header.
	 * @param mixed  $header_original Original header.
	 * @param string $pagecache_engine Engine name.
	 *
	 * @return mixed|null
	 */
	public function w3tc_pagecache_set_header( $header, $header_original, $pagecache_engine ) {
		if ( 'file_generic' === (string) $pagecache_engine ) {
			return null;
		}

		return $header;
	}
}