1 files changed, 161 insertions, 0 deletions
diff --git a/classes/Debug.php b/classes/Debug.php
new file mode 100644
index 000000000..1cda12539
--- /dev/null
+++ b/classes/Debug.php
@@ -0,0 +1,161 @@
+<?php
+class Debug {
+	const LOG_DISABLED = -1;
+	const LOG_NORMAL = 0;
+	const LOG_VERBOSE = 1;
+	const LOG_EXTENDED = 2;
+
+	const SEPARATOR = "<-{log-separator}->";
+
+	const ALL_LOG_LEVELS = [
+		Debug::LOG_DISABLED,
+		Debug::LOG_NORMAL,
+		Debug::LOG_VERBOSE,
+		Debug::LOG_EXTENDED,
+	];
+
+	/**
+	 * @deprecated
+	*/
+	public static int $LOG_DISABLED = self::LOG_DISABLED;
+
+	/**
+	 * @deprecated
+	*/
+	public static int $LOG_NORMAL = self::LOG_NORMAL;
+
+	/**
+	 * @deprecated
+	*/
+	public static int $LOG_VERBOSE = self::LOG_VERBOSE;
+
+	/**
+	 * @deprecated
+	*/
+	public static int $LOG_EXTENDED = self::LOG_EXTENDED;
+
+	private static bool $enabled = false;
+	private static bool $quiet = false;
+	private static ?string $logfile = null;
+	private static bool $enable_html = false;
+
+	private static int $loglevel = self::LOG_NORMAL;
+
+	public static function set_logfile(string $logfile): void {
+        self::$logfile = $logfile;
+    }
+
+    public static function enabled(): bool {
+        return self::$enabled;
+    }
+
+    public static function set_enabled(bool $enable): void {
+        self::$enabled = $enable;
+    }
+
+    public static function set_quiet(bool $quiet): void {
+        self::$quiet = $quiet;
+    }
+
+	/**
+	 * @param Debug::LOG_* $level
+	 */
+    public static function set_loglevel(int $level): void {
+        self::$loglevel = $level;
+    }
+
+	/**
+	 * @return int Debug::LOG_*
+	 */
+    public static function get_loglevel(): int {
+        return self::$loglevel;
+    }
+
+	/**
+	 * @param int $level integer loglevel value
+	 * @return Debug::LOG_* if valid, warn and return LOG_DISABLED otherwise
+	 */
+	public static function map_loglevel(int $level) : int {
+		if (in_array($level, self::ALL_LOG_LEVELS)) {
+			/** @phpstan-ignore-next-line */
+			return $level;
+		} else {
+			user_error("Passed invalid debug log level: $level", E_USER_WARNING);
+			return self::LOG_DISABLED;
+		}
+	}
+
+	public static function enable_html(bool $enable) : void {
+		self::$enable_html = $enable;
+	}
+
+	/**
+	 * @param Debug::LOG_* $level log level
+	 */
+    public static function log(string $message, int $level = Debug::LOG_NORMAL): bool {
+
+		if (!self::$enabled || self::$loglevel < $level) return false;
+
+		$ts = date("H:i:s", time());
+		if (function_exists('posix_getpid')) {
+			$ts = "$ts/" . posix_getpid();
+		}
+
+		$orig_message = $message;
+
+		if ($message === self::SEPARATOR) {
+			$message = self::$enable_html ? "<hr/>" :
+				"=================================================================================================================================";
+		}
+
+		if (self::$logfile) {
+			$fp = fopen(self::$logfile, 'a+');
+
+			if ($fp) {
+					$locked = false;
+
+					if (function_exists("flock")) {
+						$tries = 0;
+
+						// try to lock logfile for writing
+						while ($tries < 5 && !$locked = flock($fp, LOCK_EX | LOCK_NB)) {
+							sleep(1);
+							++$tries;
+						}
+
+						if (!$locked) {
+							fclose($fp);
+							user_error("Unable to lock debugging log file: " . self::$logfile, E_USER_WARNING);
+							return false;
+						}
+					}
+
+					fputs($fp, "[$ts] $message\n");
+
+					if (function_exists("flock")) {
+						flock($fp, LOCK_UN);
+					}
+
+					fclose($fp);
+
+					if (self::$quiet)
+						return false;
+
+			} else {
+					user_error("Unable to open debugging log file: " . self::$logfile, E_USER_WARNING);
+			}
+		}
+
+		if (self::$enable_html) {
+			if ($orig_message === self::SEPARATOR) {
+				print "$message\n";
+			} else {
+				print "<span class='log-timestamp'>$ts</span> <span class='log-message'>$message</span>\n";
+			}
+		} else {
+			print "[$ts] $message\n";
+		}
+
+		return true;
+	}
+}