WP_URL.php

<?php

use Rowbot\URL\URL;

/**
 * An abstraction to make swapping the URL parser easier later on.
 * We do not need it in the long run. It adds extra overhead of the
 * function call – let's remove it once the URL parser is decided.
 */
class WP_URL {

	static public function parse($url, $base=null) {
		return URL::parse($url, $base) ?? false;
	}

	/*
	 * Prepends a protocol to any matched URL without the double slash.
	 *
	 * Imagine we have a base URL of `https://example.com` and a text like `Visit myblog.com`.
	 * This Processor would match `myblog.com` as a URL candidate and then the parser
	 * would parse it as `https://example.com/myblog.com`, which is not what a user would expect.
	 *
	 * To get `https://myblog.com`, we need to prepend a protocol and turn that candidate into
	 * `https://myblog.com` before parsing.
	 */
	static public function ensure_protocol($raw_url, $protocol='https') {
		if ( ! self::has_double_slash($raw_url) ) {
			$raw_url = $protocol . '://' . $raw_url;
		}
		return $raw_url;
	}

	/**
	 * This method only considers http and https protocols.
	 */
	static public function has_double_slash($raw_url) {
		return (
			(
				// Protocol-relative URLs.
				strlen( $raw_url ) > 2 &&
				'/' === $raw_url[0] &&
				'/' === $raw_url[1]
			) || (
				strlen( $raw_url ) > 7 &&
				'h' === $raw_url[0] &&
				't' === $raw_url[1] &&
				't' === $raw_url[2] &&
				'p' === $raw_url[3] &&
				':' === $raw_url[4] &&
				'/' === $raw_url[5] &&
				'/' === $raw_url[6]
			) || (
				strlen( $raw_url ) > 8 &&
				'h' === $raw_url[0] &&
				't' === $raw_url[1] &&
				't' === $raw_url[2] &&
				'p' === $raw_url[3] &&
				's' === $raw_url[4] &&
				':' === $raw_url[5] &&
				'/' === $raw_url[6] &&
				'/' === $raw_url[7]
			)
		);
	}

}