Add button_url[] and hypertext element to allow mods to open web pages (#13825)

Fixes #12500

src/util/colorize.cpp

@@ -0,0 +1,113 @@
+/*
+Part of Minetest
+Copyright (C) 2024 rubenwardy
+
+Permission to use, copy, modify, and distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+
+#include "colorize.h"
+
+#ifdef USE_CURL
+
+#include <curl/urlapi.h>
+#include "log.h"
+#include "string.h"
+#include <sstream>
+
+std::string colorize_url(const std::string &url)
+{
+	// Forbid escape codes in URL
+	if (url.find('\x1b') != std::string::npos) {
+		throw std::runtime_error("Unable to open URL as it contains escape codes");
+	}
+
+	auto urlHandleRAII = std::unique_ptr<CURLU, decltype(&curl_url_cleanup)>(
+			curl_url(), curl_url_cleanup);
+	CURLU *urlHandle = urlHandleRAII.get();
+
+	auto rc = curl_url_set(urlHandle, CURLUPART_URL, url.c_str(), 0);
+	if (rc != CURLUE_OK) {
+		throw std::runtime_error("Unable to open URL as it is not valid");
+	}
+
+	auto url_get = [&] (CURLUPart what) -> std::string {
+		char *tmp = nullptr;
+		curl_url_get(urlHandle, what, &tmp, 0);
+		std::string ret(tmp ? tmp : "");
+		curl_free(tmp);
+		return ret;
+	};
+
+	auto scheme = url_get(CURLUPART_SCHEME);
+	auto user = url_get(CURLUPART_USER);
+	auto password = url_get(CURLUPART_PASSWORD);
+	auto host = url_get(CURLUPART_HOST);
+	auto port = url_get(CURLUPART_PORT);
+	auto path = url_get(CURLUPART_PATH);
+	auto query = url_get(CURLUPART_QUERY);
+	auto fragment = url_get(CURLUPART_FRAGMENT);
+	auto zoneid = url_get(CURLUPART_ZONEID);
+
+	std::ostringstream os;
+
+	std::string_view red = COLOR_CODE("#faa");
+	std::string_view white = COLOR_CODE("#fff");
+	std::string_view grey = COLOR_CODE("#aaa");
+
+	os << grey << scheme << "://";
+	if (!user.empty())
+		os << user;
+	if (!password.empty())
+		os << ":" << password;
+	if (!(user.empty() && password.empty()))
+		os << "@";
+
+	// Print hostname, escaping unsafe characters
+	os << white;
+	bool was_alphanum = true;
+	std::string host_s = host;
+	for (size_t i = 0; i < host_s.size(); i++) {
+		char c = host_s[i];
+		bool is_alphanum = isalnum(c) || ispunct(c);
+		if (is_alphanum == was_alphanum) {
+			// skip
+		} else if (is_alphanum) {
+			os << white;
+		} else {
+			os << red;
+		}
+		was_alphanum = is_alphanum;
+
+		if (is_alphanum) {
+			os << c;
+		} else {
+			os << "%" << std::setfill('0') << std::setw(2) << std::hex
+				<< (static_cast<unsigned int>(c) & 0xff);
+		}
+	}
+
+	os << grey;
+	if (!zoneid.empty())
+		os << "%" << zoneid;
+	if (!port.empty())
+		os << ":" << port;
+	os << path;
+	if (!query.empty())
+		os << "?" << query;
+	if (!fragment.empty())
+		os << "#" << fragment;
+
+	return os.str();
+}
+
+#endif