def update(self, doc, process=None):
        if process is None:
            pk = 'id'
            id = doc.id
            doc.synced = False
            set = doc
        elif process == UPDATE_PROCESS:
            if self.db.docs.find({'sid': doc.sid}).count() == 0:
                return self.insert(doc, synced=True)
            pk = 'sid'
            id = doc.sid
            doc.synced = not doc.merged() # must be commited if was merged
            doc.merged(False)
            set = {'tid': doc.tid, 'data': doc.data, 'user': doc.user,
                   'public': doc.public, 'synced': doc.synced}
        elif process == COMMIT_PROCESS:
            pk = 'id'
            id = doc.id
            doc.synced = True
            set = {'sid': doc.sid, 'tid': doc.tid, 'synced': doc.synced}
        else:
            raise DatabaseException('Incorrect update process')

        try:
            rs = self.db.docs.update({pk: id}, {'$set': set}, safe=True)
            assert rs['n'] == 1
        except Exception as e:
            raise DatabaseException(e)
        return doc
def get_list(arg=None):
	"""get list of messages"""
	frappe.form_dict['limit_start'] = int(frappe.form_dict['limit_start'])
	frappe.form_dict['limit_page_length'] = int(frappe.form_dict['limit_page_length'])
	frappe.form_dict['user'] = frappe.session['user']

	# set all messages as read
	frappe.db.begin()
	frappe.db.sql("""UPDATE `tabCommunication` set seen = 1
		where
			communication_type in ('Chat', 'Notification')
			and reference_doctype = 'User'
			and reference_name = %s""", frappe.session.user)

	delete_notification_count_for("Messages")

	frappe.local.flags.commit = True

	if frappe.form_dict['contact'] == frappe.session['user']:
		# return messages
		return frappe.db.sql("""select * from `tabCommunication`
			where
				communication_type in ('Chat', 'Notification')
				and reference_doctype ='User'
				and (owner=%(contact)s
					or reference_name=%(user)s
					or owner=reference_name)
			order by creation desc
			limit %(limit_start)s, %(limit_page_length)s""", frappe.local.form_dict, as_dict=1)
	else:
		return frappe.db.sql("""select * from `tabCommunication`
			where
				communication_type in ('Chat', 'Notification')
				and reference_doctype ='User'
				and ((owner=%(contact)s and reference_name=%(user)s)
					or (owner=%(contact)s and reference_name=%(contact)s))
			order by creation desc
			limit %(limit_start)s, %(limit_page_length)s""", frappe.local.form_dict, as_dict=1)