Add very basic Stream Management (XEP-0198) support

This implementation only counts incomming stanzas and
sends ACKs on request.
While basic this already allows servers to write
messages to offline storage that were sent to,
but never received by a client.

src/XMPPStreamManagement.m

@@ -0,0 +1,101 @@
+/*
+ * Copyright (c) 2012, Florian Zeitz <florob@babelmonkeys.de>
+ *
+ * https://webkeks.org/git/?p=objxmpp.git
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice is present in all copies.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#import "XMPPStreamManagement.h"
+#import "namespaces.h"
+
+@implementation XMPPStreamManagement
+- initWithConnection: (XMPPConnection*)connection_
+{
+	self = [super init];
+
+	@try {
+		connection = connection_;
+		[connection addDelegate: self];
+		receivedCount = 0;
+	} @catch (id e) {
+		[self release];
+		@throw e;
+	}
+
+	return self;
+}
+
+- (void)dealloc
+{
+	[connection removeDelegate: self];
+
+	[super dealloc];
+}
+
+- (void)connection: (XMPPConnection*)connection_
+ didReceiveElement: (OFXMLElement*)element
+{
+	OFString *elementName = [element name];
+	OFString *elementNS = [element namespace];
+
+	if ([elementNS isEqual: XMPP_NS_SM]) {
+		if ([elementName isEqual: @"enabled"]) {
+			receivedCount = 0;
+			return;
+		}
+
+		if ([elementName isEqual: @"failed"]) {
+			/* TODO: How do we handle this? */
+			return;
+		}
+
+		if ([elementName isEqual: @"r"]) {
+			OFXMLElement *ack =
+			    [OFXMLElement elementWithName: @"a"
+						namespace: XMPP_NS_SM];
+			[ack addAttributeWithName: @"h"
+				      stringValue:
+			    [OFString stringWithFormat: @"%" PRIu32,
+				receivedCount]];
+			[connection_ sendStanza: ack];
+		}
+	}
+
+	if ([elementNS isEqual: XMPP_NS_CLIENT] &&
+	    ([elementName isEqual: @"iq"] ||
+	     [elementName isEqual: @"presence"] ||
+	     [elementName isEqual: @"message"]))
+		receivedCount++;
+}
+
+/* TODO: Count outgoing stanzas here and cache them, send own ACK requests
+- (void)connection: (XMPPConnection*)connection_
+    didSendElement: (OFXMLElement*)element
+{
+}
+*/
+
+- (void)connection: (XMPPConnection*)connection_
+     wasBoundToJID: (XMPPJID*)jid
+{
+	if ([connection_ supportsStreamManagement])
+		[connection_ sendStanza:
+		    [OFXMLElement elementWithName: @"enable"
+					namespace: XMPP_NS_SM]];
+}
+@end