Add more debug info for "Attempted to connect a connection that is no…

…t disconnected" crash (#2353)

Frameworks/SPMySQLFramework/Source/SPMySQLConnection.h

@@ -128,6 +128,8 @@
	BOOL retryQueriesOnConnectionFailure;
	
	SPMySQLClientFlags clientFlags;
	
	NSString *_debugLastConnectedEvent;
}

#pragma mark -

Frameworks/SPMySQLFramework/Source/SPMySQLConnection.m

@@ -199,6 +199,8 @@ - (id)init
		// while running them
		retryQueriesOnConnectionFailure = YES;

		_debugLastConnectedEvent = nil;

		// Start the ping keepalive timer
		keepAliveTimer = [[SPMySQLKeepAliveTimer alloc] initWithInterval:10 target:self selector:@selector(_keepAlive)];
		
@@ -253,6 +255,8 @@ - (void) dealloc
	if (querySqlstate) [querySqlstate release], querySqlstate = nil;
	[delegateDecisionLock release];

	[_debugLastConnectedEvent release];

	[NSObject cancelPreviousPerformRequestsWithTarget:self];

	[super dealloc];
@@ -428,6 +432,14 @@ + (NSString *)findSocketPath
const char *__crashreporter_info__ = NULL;
asm(".desc ___crashreporter_info__, 0x10");

static uint64_t _elapsedMicroSecondsSinceAbsoluteTime(uint64_t comparisonTime)
{
	uint64_t elapsedTime_t = mach_absolute_time() - comparisonTime;
	Nanoseconds elapsedTime = AbsoluteToNanoseconds(*(AbsoluteTime *)&(elapsedTime_t));

	return (UnsignedWideToUInt64(elapsedTime) / 1000ULL);
}

@implementation SPMySQLConnection (PrivateAPI)

/**
@@ -438,8 +450,11 @@ - (BOOL)_connect

	// If a connection is already active in some form, throw an exception
	if (state != SPMySQLDisconnected && state != SPMySQLConnectionLostInBackground) {
		asprintf(&__crashreporter_info__, "Attempted to connect a connection that is not disconnected (SPMySQLConnectionState=%d).", state);
		__builtin_trap();
		@synchronized (self) {
			uint64_t diff = _elapsedMicroSecondsSinceAbsoluteTime(initialConnectTime);
			asprintf(&__crashreporter_info__, "Attempted to connect a connection that is not disconnected (SPMySQLConnectionState=%d).\nIf state==2: Previous connection made %lluµs ago from: %s", state, diff, [_debugLastConnectedEvent cStringUsingEncoding:NSUTF8StringEncoding]);
			__builtin_trap();
		}
		[NSException raise:NSInternalInconsistencyException format:@"Attempted to connect a connection that is not disconnected (SPMySQLConnectionState=%d).", state];
		return NO;
	}
@@ -472,7 +487,13 @@ - (BOOL)_connect

	// Successfully connected - record connected state and reset tracking variables
	state = SPMySQLConnected;
	initialConnectTime = mach_absolute_time();

	@synchronized (self) {
		initialConnectTime = mach_absolute_time();
		[_debugLastConnectedEvent release];
		_debugLastConnectedEvent = [[NSString alloc] initWithFormat:@"thread=%@ stack=%@",[NSThread currentThread],[NSThread callStackSymbols]];
	}

	mysqlConnectionThreadId = mySQLConnection->thread_id;
	lastConnectionUsedTime = initialConnectTime;