diff --git a/dcapi/boinc/assimilator.C b/dcapi/boinc/assimilator.C
index 39a1c2a0a3..a0db48720e 100644
--- a/dcapi/boinc/assimilator.C
+++ b/dcapi/boinc/assimilator.C
@@ -2,50 +2,50 @@
 #include <config.h>
 #endif
 
-#include <cstring>
-#include <cstdlib>
-#include <cstdio>
 #include <unistd.h>
-#include <ctime>
-#include <vector>
 #include <strings.h>
 
 #include "dc_boinc.h"
 
 #include <boinc_db.h>
-#include <parse.h>
-#include <util.h>
 #include <sched_util.h>
 #include <sched_msgs.h>
 
 int DC_processEvents(int timeout)
 {
 	DC_Result *result;
-	char *wu_query;
 	DB_WORKUNIT wu;
-	int ret = 0;
+	char *query;
+
+	if (!_dc_resultcb || !_dc_subresultcb || !_dc_messagecb)
+	{
+		DC_log(LOG_ERR, "DC_processEvents: callbacks are not set up");
+		return DC_ERR_CONFIG;
+	}
 
 	/* XXX Check LIMIT value */
-	wu_query = g_strdup_printf("WHERE name LIKE '%s_%%' "
+	query = g_strdup_printf("WHERE name LIKE '%s_%%' "
 		"AND assimilate_state = %d LIMIT 100", project_uuid_str,
 		ASSIMILATE_READY);
-	while (!wu.enumerate(wu_query))
+	while (!wu.enumerate(query))
 	{
 		DB_RESULT canonical_result;
-		char *result_query;
 
 		/* We are only interested in the canonical result */
 		if (!wu.canonical_resultid)
 		{
-			DC_log(LOG_DEBUG, "No canonical result for work unit %d",
-				wu.id);
+			/* This should never happen */
+			DC_log(LOG_ERR, "No canonical result for work "
+				"unit %d - bug in validator?", wu.id);
 			continue;
 		}
 
-		result_query = g_strdup_printf("WHERE id = %d",
-			wu.canonical_resultid);
-		canonical_result.lookup(result_query);
-		g_free(result_query);
+		if (canonical_result.lookup_id(wu.canonical_resultid))
+		{
+			DC_log(LOG_ERR, "Result #%d is not in the database",
+				wu.canonical_resultid);
+			continue;
+		}
 
 		/* Call the callback function */
 		result = _DC_createResult(wu.name, canonical_result.xml_doc_in);
@@ -60,6 +60,100 @@ int DC_processEvents(int timeout)
 		wu.update();
 	}
 
-	g_free(wu_query);
-	return ret;
+	g_free(query);
+	return 0;
+}
+
+/* Look for a single result that matches the filter */
+static DC_Event *look_for_results(const char *wuFilter, const char *wuName,
+	int timeout)
+{
+	DB_RESULT result;
+	DC_Event *event;
+	DB_WORKUNIT wu;
+	char *query;
+
+	if (wuFilter)
+		query = g_strdup_printf("WHERE name LIKE '%s_%%_%s' "
+			"AND assimilate_state = %d LIMIT 1", project_uuid_str,
+			wuFilter, ASSIMILATE_READY);
+	else if (wuName)
+		query = g_strdup_printf("WHERE name LIKE '%s_%s%%' "
+			"AND assimilate_state = %d LIMIT 1", project_uuid_str,
+			wuName, ASSIMILATE_READY);
+	else
+		query = g_strdup_printf("WHERE name LIKE '%s_%%' "
+			"AND assimilate_state = %d LIMIT 1", project_uuid_str,
+			ASSIMILATE_READY);
+
+	if (wu.enumerate(query))
+	{
+		g_free(query);
+		return NULL;
+	}
+	g_free(query);
+
+	if (result.lookup_id(wu.canonical_resultid))
+	{
+		DC_log(LOG_ERR, "Result #%d is not in the database",
+			wu.canonical_resultid);
+		return NULL;
+	}
+
+	event = g_new(DC_Event, 1);
+	event->type = DC_EVENT_RESULT;
+	event->result = _DC_createResult(wu.name, result.xml_doc_in);
+	if (!event->result)
+	{
+		g_free(event);
+		return NULL;
+	}
+
+	return event;
+}
+
+DC_Event *DC_waitEvent(const char *wuFilter, int timeout)
+{
+	DC_Event *event;
+
+	event = look_for_results(wuFilter, NULL, timeout);
+/*
+	if (!event)
+		event = look_for_notifications(...)
+*/
+	return event;
+}
+
+DC_Event *DC_waitWUEvent(DC_Workunit *wu, int timeout)
+{
+	DC_Event *event;
+
+	event = look_for_results(NULL, wu->name, timeout);
+/*
+	if (!event)
+		event = look_for_notifications(...)
+*/
+	return event;
+}
+
+void DC_DestroyEvent(DC_Event *event)
+{
+	if (!event)
+		return;
+
+	switch (event->type)
+	{
+		case DC_EVENT_RESULT:
+			_DC_destroyResult(event->result);
+			break;
+		case DC_EVENT_SUBRESULT:
+			_DC_destroyPhysicalFile(event->subresult);
+			break;
+		case DC_EVENT_MESSAGE:
+			g_free(event->message);
+			break;
+		default:
+			DC_log(LOG_ERR, "Unknown event type %d", event->type);
+			break;
+	}
 }