Use exceptions.

src/XMPPConnection.m

@@ -29,6 +29,7 @@
 #import "XMPPStanza.h"
 #import "XMPPJID.h"
 #import "XMPPIQ.h"
+#import "XMPPExceptions.h"
 
 #define NS_BIND @"urn:ietf:params:xml:ns:xmpp-bind"
 #define NS_CLIENT @"jabber:client"
@@ -36,14 +37,7 @@
 #define NS_STREAM @"http://etherx.jabber.org/streams"
 
 @implementation XMPPConnection
-@synthesize username;
-@synthesize password;
-@synthesize server;
-@synthesize resource;
-@synthesize JID;
-@synthesize port;
-@synthesize useTLS;
-@synthesize delegate;
+@synthesize username, password, server, resource, JID, port, useTLS, delegate;
 
 - init
 {
@@ -77,13 +71,14 @@
 {
 	OFString *old = username;
 	char *node;
-
 	Stringprep_rc rc;
+
 	if ((rc = stringprep_profile([username_ cString], &node,
-	    "SASLprep", 0)) != STRINGPREP_OK) {
-		of_log(@"SASLprep failed: %s", stringprep_strerror(rc));
-		assert(0);
-	}
+	    "SASLprep", 0)) != STRINGPREP_OK)
+		@throw [XMPPStringPrepFailedException newWithClass: isa
+							connection: self
+							   profile: @"SASLprep"
+							    string: username_];
 
 	@try {
 		username = [[OFString alloc] initWithCString: node];
@@ -98,13 +93,15 @@
 {
 	OFString *old = resource;
 	char *res;
-
 	Stringprep_rc rc;
+
 	if ((rc = stringprep_profile([resource_ cString], &res,
-	    "Resourceprep", 0)) != STRINGPREP_OK) {
-		of_log(@"Resourceprep failed: %s", stringprep_strerror(rc));
-		assert(0);
-	}
+	    "Resourceprep", 0)) != STRINGPREP_OK)
+		@throw [XMPPStringPrepFailedException
+		    newWithClass: isa
+		      connection: self
+			 profile: @"Resourceprep"
+			  string: resource_];
 
 	@try {
 		resource = [[OFString alloc] initWithCString: res];
@@ -119,13 +116,14 @@
 {
 	OFString *old = server;
 	char *srv;
-
 	Stringprep_rc rc;
+
 	if ((rc = stringprep_profile([server_ cString], &srv,
-	    "Nameprep", 0)) != STRINGPREP_OK) {
-		of_log(@"Nameprep failed: %s", stringprep_strerror(rc));
-		assert(0);
-	}
+	    "Nameprep", 0)) != STRINGPREP_OK)
+		@throw [XMPPStringPrepFailedException newWithClass: isa
+							connection: self
+							   profile: @"Nameprep"
+							    string: server_];
 
 	@try {
 		server = [[OFString alloc] initWithCString: srv];
@@ -140,13 +138,14 @@
 {
 	OFString *old = password;
 	char *pass;
-
 	Stringprep_rc rc;
+
 	if ((rc = stringprep_profile([password_ cString], &pass,
-	    "SASLprep", 0)) != STRINGPREP_OK) {
-		of_log(@"SASLprep failed: %s", stringprep_strerror(rc));
-		assert(0);
-	}
+	    "SASLprep", 0)) != STRINGPREP_OK)
+		@throw [XMPPStringPrepFailedException newWithClass: isa
+							connection: self
+							   profile: @"SASLprep"
+							    string: password_];
 
 	@try {
 		password = [[OFString alloc] initWithCString: pass];

src/XMPPExceptions.h

@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2011, Jonathan Schleifer <js@webkeks.org>
+ *
+ * https://webkeks.org/hg/objxmpp/
+ *
+ * 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 <ObjFW/ObjFW.h>
+
+@class XMPPConnection;
+
+@interface XMPPException: OFException
+{
+	XMPPConnection *connection;
+}
+
+@property (readonly, nonatomic) XMPPConnection *connection;
+
++ newWithClass: (Class)class_
+    connection: (XMPPConnection*)conn;
+- initWithClass: (Class)class_
+     connection: (XMPPConnection*)conn;
+@end
+
+@interface XMPPStringPrepFailedException: XMPPException
+{
+	OFString *profile;
+	OFString *string;
+}
+
+@property (readonly, nonatomic) OFString *profile, *string;
+
++ newWithClass: (Class)class_
+    connection: (XMPPConnection*)conn
+       profile: (OFString*)profile
+	string: (OFString*)string;
+- initWithClass: (Class)class_
+     connection: (XMPPConnection*)conn
+	profile: (OFString*)profile
+	 string: (OFString*)string;
+@end

src/XMPPExceptions.m

@@ -0,0 +1,131 @@
+/*
+ * Copyright (c) 2011, Jonathan Schleifer <js@webkeks.org>
+ *
+ * https://webkeks.org/hg/objxmpp/
+ *
+ * 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 "XMPPExceptions.h"
+
+@implementation XMPPException
+@synthesize connection;
+
++ newWithClass: (Class)class_
+    connection: (XMPPConnection*)conn
+{
+	return [[self alloc] initWithClass: class_
+				connection: conn];
+}
+
+- initWithClass: (Class)class_
+{
+	Class c = isa;
+	[self release];
+	@throw [OFNotImplementedException newWithClass: c
+					      selector: _cmd];
+}
+
+- initWithClass: (Class)class_
+     connection: (XMPPConnection*)conn
+{
+	self = [super initWithClass: class_];
+
+	@try {
+		connection = [conn retain];
+	} @catch (id e) {
+		[self release];
+		@throw e;
+	}
+
+	return self;
+}
+
+- (void)dealloc
+{
+	[connection release];
+
+	[super dealloc];
+}
+
+- (OFString*)description
+{
+	OFAutoreleasePool *pool;
+
+	if (description != nil)
+		return description;
+
+	pool = [[OFAutoreleasePool alloc] init];
+	description = [[OFString alloc]
+	    initWithFormat: @"An exception occurred in class %@!",
+			    [self className]];
+	[pool release];
+
+	return description;
+}
+@end
+
+@implementation XMPPStringPrepFailedException
+@synthesize profile, string;
+
++ newWithClass: (Class)class_
+    connection: (XMPPConnection*)conn
+       profile: (OFString*)profile
+	string: (OFString*)string
+{
+	return [[self alloc] initWithClass: class_
+				connection: conn
+				   profile: profile
+				    string: string];
+}
+
+- initWithClass: (Class)class_
+     connection: (XMPPConnection*)conn
+{
+	Class c = isa;
+	[self release];
+	@throw [OFNotImplementedException newWithClass: c
+					      selector: _cmd];
+}
+
+- initWithClass: (Class)class_
+     connection: (XMPPConnection*)conn
+	profile: (OFString*)profile_
+	 string: (OFString*)string_
+{
+	self = [super initWithClass: class_
+			 connection: conn];
+
+	@try {
+		profile = [profile_ copy];
+		string = [string_ copy];
+	} @catch (id e) {
+		[self release];
+		@throw e;
+	}
+
+	return self;
+}
+
+- (void)dealloc
+{
+	[profile release];
+	[string release];
+
+	[super dealloc];
+}
+@end

src/XMPPIQ.m

@@ -34,14 +34,20 @@
 - initWithType: (OFString*)type_
 	    ID: (OFString*)ID_
 {
-	if (![type_ isEqual: @"get"] &&
-	    ![type_ isEqual: @"set"] &&
-	    ![type_ isEqual: @"result"] &&
-	    ![type_ isEqual: @"error"])
-		of_log(@"Invalid IQ type!");
-
-	return [super initWithName: @"iq"
+	self = [super initWithName: @"iq"
 			      type: type_
 				ID: ID_];
+
+	@try {
+		if (![type_ isEqual: @"get"] && ![type_ isEqual: @"set"] &&
+		    ![type_ isEqual: @"result"] && ![type_ isEqual: @"error"])
+			@throw [OFInvalidArgumentException newWithClass: isa
+							       selector: _cmd];
+	} @catch (id e) {
+		[self release];
+		@throw e;
+	}
+
+	return self;
 }
 @end

src/XMPPStanza.m

@@ -57,7 +57,8 @@
 					ID: ID_] autorelease];
 }
 
-+ stanzaWithElement: (OFXMLElement*)elem {
++ stanzaWithElement: (OFXMLElement*)elem
+{
 	return [[[self alloc] initWithElement: elem] autorelease];
 }
 
@@ -88,14 +89,14 @@
 	  type: (OFString*)type_
 	    ID: (OFString*)ID_
 {
-	if (![name_ isEqual: @"iq"] &&
-	    ![name_ isEqual: @"message"] &&
-	    ![name_ isEqual: @"presence"])
-		of_log(@"Invalid stanza name!");
-
 	self = [super initWithName: name_];
 
 	@try {
+		if (![name_ isEqual: @"iq"] && ![name_ isEqual: @"message"] &&
+		    ![name_ isEqual: @"presence"])
+			@throw [OFInvalidArgumentException newWithClass: isa
+							       selector: _cmd];
+
 		[self setDefaultNamespace: @"jabber:client"];
 
 		if (type_)