feat: Improve validation of JIDs

Add new `jid_is_valid()` function and improve the adherence to XMPP RFCs
in jid_create().

Add unit tests for them as well.

tests/unittests/unittests.c

@@ -150,6 +150,14 @@ main(int argc, char* argv[])
         cmocka_unit_test(jid_create__returns__correct_parts_with_trailing_slash),
         cmocka_unit_test(jid_fulljid_or_barejid__returns__fulljid_when_exists),
         cmocka_unit_test(jid_fulljid_or_barejid__returns__barejid_when_fulljid_not_exists),
+        cmocka_unit_test(jid_create__returns__null_from_invalid_localpart_chars),
+        cmocka_unit_test(jid_create__returns__null_from_empty_parts),
+        cmocka_unit_test(jid_create__returns__null_from_multiple_at_in_bare),
+        cmocka_unit_test(jid_create__returns__correct_parts_with_at_in_resource_only),
+        cmocka_unit_test(jid_is_valid__is__true_for_valid_jid),
+        cmocka_unit_test(jid_is_valid__is__false_for_invalid_jid),
+        cmocka_unit_test(jid_is_valid__is__false_for_null),
+        cmocka_unit_test(jid_is_valid__is__false_for_empty_string),
 
         cmocka_unit_test(parse_args__returns__null_from_null),
         cmocka_unit_test(parse_args__returns__null_from_empty),

tests/unittests/xmpp/test_jid.c

@@ -234,3 +234,102 @@ jid_fulljid_or_barejid__returns__barejid_when_fulljid_not_exists(void** state)
 
     jid_destroy(jid);
 }
+
+void
+jid_create__returns__null_from_invalid_localpart_chars(void** state)
+{
+    // Space
+    Jid* result = jid_create("user name@domain.com");
+    assert_null(result);
+
+    // Double quote
+    result = jid_create("user\"name@domain.com");
+    assert_null(result);
+
+    // Ampersand
+    result = jid_create("user&name@domain.com");
+    assert_null(result);
+
+    // Single quote
+    result = jid_create("user'name@domain.com");
+    assert_null(result);
+
+    // Colon
+    result = jid_create("user:name@domain.com");
+    assert_null(result);
+
+    // Less than
+    result = jid_create("user<name@domain.com");
+    assert_null(result);
+
+    // Greater than
+    result = jid_create("user>name@domain.com");
+    assert_null(result);
+}
+
+void
+jid_create__returns__null_from_empty_parts(void** state)
+{
+    // Empty local
+    Jid* result = jid_create("@domain.com");
+    assert_null(result);
+
+    // Empty domain (trailing @)
+    result = jid_create("user@");
+    assert_null(result);
+
+    // Empty resource (trailing /)
+    result = jid_create("user@domain.com/");
+    assert_null(result);
+
+    // Empty domain in full jid
+    result = jid_create("user@/resource");
+    assert_null(result);
+}
+
+void
+jid_create__returns__null_from_multiple_at_in_bare(void** state)
+{
+    Jid* result = jid_create("user@domain@other.com");
+    assert_null(result);
+}
+
+void
+jid_create__returns__correct_parts_with_at_in_resource_only(void** state)
+{
+    // domain.com/user@host (no localpart)
+    Jid* result = jid_create("domain.com/user@host");
+    assert_non_null(result);
+    assert_null(result->localpart);
+    assert_string_equal("domain.com", result->domainpart);
+    assert_string_equal("user@host", result->resourcepart);
+    jid_destroy(result);
+}
+
+void
+jid_is_valid__is__true_for_valid_jid(void** state)
+{
+    assert_true(jid_is_valid("myuser@mydomain/laptop"));
+    assert_true(jid_is_valid("myuser@mydomain"));
+    assert_true(jid_is_valid("mydomain/laptop"));
+    assert_true(jid_is_valid("mydomain"));
+}
+
+void
+jid_is_valid__is__false_for_invalid_jid(void** state)
+{
+    assert_false(jid_is_valid("@mydomain"));
+    assert_false(jid_is_valid("/laptop"));
+}
+
+void
+jid_is_valid__is__false_for_null(void** state)
+{
+    assert_false(jid_is_valid(NULL));
+}
+
+void
+jid_is_valid__is__false_for_empty_string(void** state)
+{
+    assert_false(jid_is_valid(""));
+}

tests/unittests/xmpp/test_jid.h

@@ -26,5 +26,13 @@ void jid_create__returns__correct_parts_with_at_and_slash_in_resource(void** sta
 void jid_create__returns__correct_parts_with_trailing_slash(void** state);
 void jid_fulljid_or_barejid__returns__fulljid_when_exists(void** state);
 void jid_fulljid_or_barejid__returns__barejid_when_fulljid_not_exists(void** state);
+void jid_create__returns__null_from_invalid_localpart_chars(void** state);
+void jid_create__returns__null_from_empty_parts(void** state);
+void jid_create__returns__null_from_multiple_at_in_bare(void** state);
+void jid_create__returns__correct_parts_with_at_in_resource_only(void** state);
+void jid_is_valid__is__true_for_valid_jid(void** state);
+void jid_is_valid__is__false_for_invalid_jid(void** state);
+void jid_is_valid__is__false_for_null(void** state);
+void jid_is_valid__is__false_for_empty_string(void** state);
 
 #endif