<!-- Module Developer's Guide -->

<chapter>
    <chapterinfo>
	<revhistory>
	    <revision>
		<revnumber>$Revision: 1.5 $</revnumber>
		<date>$Date: 2004/08/24 09:00:48 $</date>
	    </revision>
	</revhistory>
    </chapterinfo>
    <title>Developer's Guide</title>
    <section>
	<title>Available Functions</title>
	<section>
	    <title>
		<function moreinfo="none">ul_register_domain(name)</function>
	    </title>
	    <para>
		The function registers a new domain. Domain is just another name for table used in
		registrar. The function is called from fixups in registrar. It gets name of the
		domain as a parameter and returns pointer to a new domain structure. The fixup than
		'fixes' the parameter in registrar so that it will pass the pointer instead of the
		name every time save() or lookup() is called. Some usrloc functions get the pointer
		as parameter when called. For more details see implementation of save function in
		registrar.
	    </para>
	    <para>Meaning of the parameters is as follows:</para>
	    <itemizedlist>
		<listitem>
		    <para><emphasis>const char* name</emphasis> - Name of the domain (also called
                            table) to be registered.
		    </para>
		</listitem>
	    </itemizedlist>
	</section>

	<section>
	    <title>
		<function moreinfo="none">ul_insert_urecord(domain, aor, rec)</function>
	    </title>
	    <para>
		The function creates a new record structure and inserts it in the specified
		domain. The record is structure that contains all the contacts for belonging to the
		specified username.
	    </para>
	    <para>Meaning of the parameters is as follows:</para>
	    <itemizedlist>
		<listitem>
		    <para><emphasis>udomain_t* domain</emphasis> - Pointer to domain returned by ul_register_udomain.
		    </para>
		</listitem>
	    </itemizedlist>
	    <itemizedlist>
		<listitem>
		    <para><emphasis>str* aor</emphasis> - Address of Record (aka username) of the
                            new record (at this time the record will contain no contacts yet).
		    </para>
		</listitem>
	    </itemizedlist>
	    <itemizedlist>
		<listitem>
		    <para><emphasis>urecord_t** rec</emphasis> - The newly created record structure.
		    </para>
		</listitem>
	    </itemizedlist>
	</section>


	<section>
	    <title>
		<function moreinfo="none">ul_delete_urecord(domain, aor)</function>
	    </title>
	    <para>
		The function deletes all the contacts bound with the given Address Of Record.
	    </para>
	    <para>Meaning of the parameters is as follows:</para>
	    <itemizedlist>
		<listitem>
		    <para><emphasis>udomain_t* domain</emphasis> - Pointer to domain returned by ul_register_udomain.
		    </para>
		</listitem>
	    </itemizedlist>
	    <itemizedlist>
		<listitem>
		    <para><emphasis>str* aor</emphasis> - Address of record (aka username) of the
                            record, that should be deleted.
		    </para>
		</listitem>
	    </itemizedlist>
	</section>

	<section>
	    <title>
		<function moreinfo="none">ul_get_urecord(domain, aor)</function>
	    </title>
	    <para>
		The function returns pointer to record with given Address of Record.
	    </para>
	    <para>Meaning of the parameters is as follows:</para>
	    <itemizedlist>
		<listitem>
		    <para><emphasis>udomain_t* domain</emphasis> - Pointer to domain returned by ul_register_udomain.
		    </para>
		</listitem>
	    </itemizedlist>
	    <itemizedlist>
		<listitem>
		    <para><emphasis>str* aor</emphasis> - Address of Record of request record.
		    </para>
		</listitem>
	    </itemizedlist>
	</section>

	<section>
	    <title>
		<function moreinfo="none">ul_lock_udomain(domain)</function>
	    </title>
	    <para>
		The function lock the specified domain, it means, that no other processes will be
		able to access during the time. This prevents race conditions. Scope of the lock is
		the specified domain, that means, that multiple domain can be accessed
		simultaneously, they don't block each other.
	    </para>
	    <para>Meaning of the parameters is as follows:</para>
	    <itemizedlist>
		<listitem>
		    <para><emphasis>udomain_t* domain</emphasis> - Domain to be locked.
		    </para>
		</listitem>
	    </itemizedlist>
	</section>

	<section>
	    <title>
		<function moreinfo="none">ul_unlock_udomain(domain)</function>
	    </title>
	    <para>
		Unlock the specified domain previously locked by ul_lock_udomain.
	    </para>
	    <para>Meaning of the parameters is as follows:</para>
	    <itemizedlist>
		<listitem>
		    <para><emphasis>udomain_t* domain</emphasis> - Domain to be unlocked.
		    </para>
		</listitem>
	    </itemizedlist>
	</section>

	<section>
	    <title>
		<function moreinfo="none">ul_release_urecord(record)</function>
	    </title>
	    <para>
		Do some sanity checks - if all contacts have been removed, delete the entire record
		structure.
	    </para>
	    <para>Meaning of the parameters is as follows:</para>
	    <itemizedlist>
		<listitem>
		    <para><emphasis>urecord_t* record</emphasis> - Record to be released.
		    </para>
		</listitem>
	    </itemizedlist>
	</section>

	<section>
	    <title>
		<function moreinfo="none">ul_insert_ucontact(record, contact, expires, q, callid,
		cseq, flags, cont, ua)</function>
	    </title>
	    <para>
		The function inserts a new contact in the given record with specified parameters.
	    </para>
	    <para>Meaning of the parameters is as follows:</para>
	    <itemizedlist>
		<listitem>
		    <para><emphasis>urecord_t* record</emphasis> - Record in which the contact should be inserted.
		    </para>
		</listitem>
	    </itemizedlist>
	    <itemizedlist>
		<listitem>
		    <para><emphasis>str* contact</emphasis> - Contact &uri;.
		    </para>
		</listitem>
	    </itemizedlist>
	    <itemizedlist>
		<listitem>
		    <para><emphasis>time_t expires</emphasis> - Expires of the contact in absolute value.
		    </para>
		</listitem>
	    </itemizedlist>
	    <itemizedlist>
		<listitem>
		    <para><emphasis>float q</emphasis> - q value of the contact.
		    </para>
		</listitem>
	    </itemizedlist>
	    <itemizedlist>
		<listitem>
		    <para><emphasis>str* callid</emphasis> - Call-ID of the REGISTER message that contained the contact.
		    </para>
		</listitem>
	    </itemizedlist>
	    <itemizedlist>
		<listitem>
		    <para><emphasis>int cseq</emphasis> - CSeq of the REGISTER message that contained the contact.
		    </para>
		</listitem>
	    </itemizedlist>
	    <itemizedlist>
		<listitem>
		    <para><emphasis>unsigned int flags</emphasis> - Flags to be set.
			</para> 
		</listitem>
	    </itemizedlist>
	    <itemizedlist>
		<listitem>
		    <para><emphasis>ucontact_t* cont</emphasis> - Pointer to newly created structure.
		    </para>
		</listitem>
	    </itemizedlist>
	    <itemizedlist>
		<listitem>
		    <para><emphasis>str* ua</emphasis> - User-Agent of the REGISTER message that contained the contact.
		    </para>
		</listitem>
	    </itemizedlist>
	</section>

	<section>
	    <title>
		<function moreinfo="none">ul_delete_ucontact(record, contact)</function>
	    </title>
	    <para>
		The function deletes given contact from record.
	    </para>
	    <para>Meaning of the parameters is as follows:</para>
	    <itemizedlist>
		<listitem>
		    <para><emphasis>urecord_t* record</emphasis> - Record from which the contact should be removed.
		    </para>
		</listitem>
	    </itemizedlist>
	    <itemizedlist>
		<listitem>
		    <para><emphasis>ucontact_t* contact</emphasis> - Contact to be deleted.
		    </para>
		</listitem>
	    </itemizedlist>
	</section>

	<section>
	    <title>
		<function moreinfo="none">ul_get_ucontact(record, contact)</function>
	    </title>
	    <para>
		The function tries to find contact with given Contact &uri; and returns pointer to
		structure representing the contact.
	    </para>
	    <para>Meaning of the parameters is as follows:</para>
	    <itemizedlist>
		<listitem>
		    <para><emphasis>urecord_t* record</emphasis> - Record to be searched for the contact.
		    </para>
		</listitem>
	    </itemizedlist>
	    <itemizedlist>
		<listitem>
		    <para><emphasis>str_t* contact</emphasis> - &uri; of the request contact.
		    </para>
		</listitem>
	    </itemizedlist>
	</section>

	<section>
	    <title>
		<function moreinfo="none">ul_get_all_ucontacts(buf, len, flags)</function>
	    </title>
	    <para>
		The function retrieves all contacts of all registered users and returns them in the
		caller-supplied buffer. If the buffer is too small, the function returns positive
		value indicating how much additional space would be necessary to accommodate all of
		them. Please note that the positive return value should be used only as a
		<quote>hint</quote>, as there is no guarantee that during the time between two
		subsequent calls number of registered contacts will remain the same.
	    </para>
	    <para>
		If flag parameter is set to non-zero value then only contacts that have the
		specified flags set will be returned. It is, for example, possible to list only
		contacts that are behind NAT.
	    </para>
	    <para>Meaning of the parameters is as follows:</para>
	    <itemizedlist>
		<listitem>
		    <para><emphasis>void* buf</emphasis> - Buffer for returning contacts.
		    </para>
		</listitem>
	    </itemizedlist>
	    <itemizedlist>
		<listitem>
		    <para><emphasis>int len</emphasis> - Length of the buffer.
		    </para>
		</listitem>
	    </itemizedlist>
	    <itemizedlist>
		<listitem>
		    <para><emphasis>unsigned int flags</emphasis> - Flags that must be set.
		    </para>
		</listitem>
	    </itemizedlist>
	</section>

	<section>
	    <title>
		<function moreinfo="none">ul_update_ucontact(contact, expires, q, callid,
		cseq, set, res, ua)</function>
	    </title>
	    <para>
		The function updates contact with new values.
	    </para>
	    <para>Meaning of the parameters is as follows:</para>
	    <itemizedlist>
		<listitem>
		    <para><emphasis>ucontact_t* contact</emphasis> - Contact &uri;.
		    </para>
		</listitem>
	    </itemizedlist>
	    <itemizedlist>
		<listitem>
		    <para><emphasis>time_t expires</emphasis> - Expires of the contact in absolute value.
		    </para>
		</listitem>
	    </itemizedlist>
	    <itemizedlist>
		<listitem>
		    <para><emphasis>float q</emphasis> - q value of the contact.
		    </para>
		</listitem>
	    </itemizedlist>
	    <itemizedlist>
		<listitem>
		    <para><emphasis>str* callid</emphasis> - Call-ID of the REGISTER message that contained the contact.
		    </para>
		</listitem>
	    </itemizedlist>
	    <itemizedlist>
		<listitem>
		    <para><emphasis>int cseq</emphasis> - CSeq of the REGISTER message that contained the contact.
		    </para>
		</listitem>
	    </itemizedlist>
	    <itemizedlist>
		<listitem>
		    <para>
			<emphasis>unsigned int set</emphasis> - OR value of flags to be set.
		    </para>
		</listitem>
	    </itemizedlist>
	    <itemizedlist>
		<listitem>
		    <para>
			<emphasis>unsigned int res</emphasis> - OR value of flags to be reset.
		    </para>
		</listitem>
	    </itemizedlist>
	    <itemizedlist>
		<listitem>
		    <para>
			<para><emphasis>str* ua</emphasis> - User-Agent of the REGISTER message that contained the contact.
		    </para>
		</listitem>
	    </itemizedlist>
	</section>
    </section>
	<section>
	<title>Contact states</title>
		<figure id="ucontact-states" float="0">
			<title>States of a ucontact</title>
			<mediaobject>
				<imageobject>
					<imagedata align="center" fileref="usrloc_states_w_zombie.png" format="PNG">
				</imageobject>
			</mediaobject>
		</figure>
		<para>
		Contacts in one of the zombie states should be ignored by any function
		which interacts with an external user. Contacts are only kept in a
		zombie state to store the informations for replication. Contacts can
		also appear in a zombie state even if no replication is used, but in
		this case the contacts should be removed by the next timer event 
		automatically.
		</para>
	</section>
</chapter>

<!-- Keep this element at the end of the file
Local Variables:
sgml-parent-document: ("usrloc.sgml" "book" "chapter")
End:
-->
