Send out log messages via UDP even if global logging queue is suspended

Monal/Classes/HelperTools.m

@@ -394,10 +394,38 @@ @implementation DDLog (AllowQueueFreeze)
 
 -(void) swizzled_queueLogMessage:(DDLogMessage*) logMessage asynchronously:(BOOL) asyncFlag
 {
+    //make sure this method remains performant even when checking for udp logging presence
+    static BOOL udpLoggerEnabled = NO;
+    static dispatch_once_t onceToken;
+    dispatch_once(&onceToken, ^{
+        udpLoggerEnabled = [[HelperTools defaultsDB] boolForKey:@"udpLoggerEnabled"];
+    });
+
     //don't do sync logging for any message (usually ERROR), while the global logging queue is suspended
-    @synchronized(_suspensionHandling_lock) {
-        return [self swizzled_queueLogMessage:logMessage asynchronously:_suspensionHandling_isSuspended ? YES : asyncFlag];
+    //don't use _suspensionHandling_lock here because that can introduce deadlocks
+    //(for example if we have log statements in our MLLogFileManager code rotating the logfile and creating a new one)
+    BOOL isSuspended = _suspensionHandling_isSuspended;
+    if(isSuspended && udpLoggerEnabled)
+    {
+        //use udp logger to log all messages, even if the loggging queue is in suspended state
+        //this hopefully enables us to catch strange bugs sometimes hanging and then watchdog-killing the app when resuming from resumption
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated-declarations"
+        [MLUDPLogger directlyWriteLogMessage:[[DDLogMessage alloc]
+             initWithFormat:logMessage.messageFormat
+                  formatted:[NSString stringWithFormat:@"LOG_QUEUE_DISABLED: %@", logMessage.message]
+                      level:logMessage.level
+                       flag:logMessage.flag
+                    context:logMessage.context
+                       file:logMessage.file
+                   function:logMessage.function
+                       line:logMessage.line
+                        tag:logMessage.tag
+                    options:logMessage.options
+                  timestamp:logMessage.timestamp]];
+#pragma clang diagnostic pop
     }
+    return [self swizzled_queueLogMessage:logMessage asynchronously:isSuspended ? YES : asyncFlag];
 }
 
 //see https://stackoverflow.com/a/13326633 and https://fek.io/blog/method-swizzling-in-obj-c-and-swift/

Monal/Classes/MLUDPLogger.h

@@ -11,9 +11,12 @@
 
 NS_ASSUME_NONNULL_BEGIN
 
+FOUNDATION_EXPORT DDLoggerName const DDLoggerNameUDP NS_SWIFT_NAME(DDLoggerName.udp); // MLUDPLogger
+
 @interface MLUDPLogger : DDAbstractLogger <DDLogger>
 
 +(void) flushWithTimeout:(double) timeout;
++(void) directlyWriteLogMessage:(DDLogMessage*) logMessage;
 
 @end
 

Monal/Classes/MLUDPLogger.m

@@ -19,6 +19,8 @@
 #import "MLContact.h"
 #import "xmpp.h"
 
+DDLoggerName const DDLoggerNameUDP = @"monal.loggger.udp.mainQueue";
+
 static NSData* _key;
 static volatile MLUDPLogger* _self;
 
@@ -78,6 +80,16 @@ +(void) flushWithTimeout:(double) timeout
     }
 }
 
++(void) directlyWriteLogMessage:(DDLogMessage*) logMessage
+{
+    if(_self == nil)
+    {
+        [[self class] logError:@"Ignoring call to directlySyncWriteLogMessage: _self still nil!"];
+        return;
+    }
+    return [_self logMessage:logMessage];
+}
+
 -(void) dealloc
 {
     _self = nil;
@@ -87,14 +99,20 @@ -(void) didAddLogger
 {
     _self = self;
     _send_condition = [NSCondition new];
-    _send_queue = dispatch_queue_create("MLUDPLoggerSendQueue", dispatch_queue_attr_make_with_qos_class(DISPATCH_QUEUE_SERIAL, QOS_CLASS_USER_INTERACTIVE, 0));
+    _send_queue = dispatch_queue_create("MLUDPLoggerInternalSendQueue", dispatch_queue_attr_make_with_qos_class(DISPATCH_QUEUE_SERIAL, QOS_CLASS_USER_INTERACTIVE, 0));
 }
 
 -(void) willRemoveLogger
 {
     _self = nil;
 }
 
+
+-(DDLoggerName) loggerName
+{
+    return DDLoggerNameUDP;
+}
+
 +(void) logError:(NSString*) format, ... NS_FORMAT_FUNCTION(1, 2)
 {
 #ifdef IS_ALPHA