ObjFW  Check-in [252f11c431]

@class OFDNSResolver;
@class OFDNSResolverContext;
@class OFDNSResolverSettings;
@class OFDate;
@class OFDictionary OF_GENERIC(KeyType, ObjectType);
@class OFMutableDictionary OF_GENERIC(KeyType, ObjectType);
@class OFNumber;
@class OFPair OF_GENERIC(FirstType, SecondType);
@class OFTCPSocket;
@class OFUDPSocket;

/**
 * @enum OFDNSResolverErrorCode OFDNSResolver.h ObjFW/OFDNSResolver.h
 *
 * @brief An enum describing why resolving a host failed.

	OFUDPSocket *_IPv6Socket;
#endif
	char _buffer[OFDNSResolverBufferLength];
	OFMutableDictionary OF_GENERIC(OFNumber *, OFDNSResolverContext *)
	    *_queries;
	OFMutableDictionary OF_GENERIC(OFTCPSocket *, OFDNSResolverContext *)
	    *_TCPQueries;
	OFMutableDictionary OF_GENERIC(OFDNSQuery *,
	    OFPair OF_GENERIC(OFDate *, OFDNSResponse *) *) *_cache;
}

/**
 * @brief A dictionary of static hosts.
 *
 * This dictionary is checked before actually looking up a host.
 */

	while ((array = [objectEnumerator nextObject]) != nil)
		[array makeImmutable];

	[ret makeImmutable];

	return ret;
}

static bool
containsExpiredRecord(OFDNSResponseRecords responseRecords, uint32_t age)
{
	OFEnumerator *enumerator = [responseRecords objectEnumerator];
	OFArray OF_GENERIC(OFDNSResourceRecord *) *records;

	while ((records = [enumerator nextObject]) != nil)
		for (OFDNSResourceRecord *record in records)
			if (record.TTL < age)
				return true;

	return false;
}

@implementation OFDNSResolverContext
- (instancetype)initWithQuery: (OFDNSQuery *)query
			   ID: (OFNumber *)ID
		     settings: (OFDNSResolverSettings *)settings
		     delegate: (id <OFDNSResolverQueryDelegate>)delegate
{

{
	self = [super init];

	@try {
		_settings = [[OFDNSResolverSettings alloc] init];
		_queries = [[OFMutableDictionary alloc] init];
		_TCPQueries = [[OFMutableDictionary alloc] init];
		_cache = [[OFMutableDictionary alloc] init];

		[_settings reload];
	} @catch (id e) {
		[self release];
		@throw e;
	}

	[_IPv4Socket release];
#ifdef OF_HAVE_IPV6
	[_IPv6Socket cancelAsyncRequests];
	[_IPv6Socket release];
#endif
	[_queries release];
	[_TCPQueries release];
	[_cache release];

	[super dealloc];
}

- (OFDictionary *)staticHosts
{
	return _settings->_staticHosts;

- (void)asyncPerformQuery: (OFDNSQuery *)query
	      runLoopMode: (OFRunLoopMode)runLoopMode
		 delegate: (id <OFDNSResolverQueryDelegate>)delegate
{
	void *pool = objc_autoreleasePoolPush();
	OFNumber *ID;
	OFDNSResolverContext *context;
	OFPair OF_GENERIC(OFDate *, OFDNSResponse *) *cacheEntry;

	if ((cacheEntry = [_cache objectForKey: query]) != nil) {
		uint32_t age =
		    (uint32_t)-[cacheEntry.firstObject timeIntervalSinceNow];
		OFDNSResponse *response = cacheEntry.secondObject;

		if (!containsExpiredRecord(response.answerRecords, age) &&
		    !containsExpiredRecord(response.authorityRecords, age) &&
		    !containsExpiredRecord(response.additionalRecords, age)) {
			[delegate resolver: self
			   didPerformQuery: query
				  response: response
				 exception: nil];

			objc_autoreleasePoolPop(pool);
			return;
		}
	}

	/* Random, unused ID */
	do {
		ID = [OFNumber numberWithUnsignedShort: OFRandom16()];
	} while ([_queries objectForKey: ID] != nil);

	if (query.domainName.UTF8StringLength > 253)

	} @catch (id e) {
		exception = e;
	}

	if (exception != nil)
		response = nil;

	if (response != nil)
		[_cache setObject: [OFPair pairWithFirstObject: [OFDate date]
						  secondObject: response]
			   forKey: context->_query];
	else
		[_cache removeObjectForKey: context->_query];

	[context->_delegate resolver: self
		     didPerformQuery: context->_query
			    response: response
			   exception: exception];

	return false;
}