From 0bbc551746605e85adff961c9049a61e44fffd00 Mon Sep 17 00:00:00 2001
From: Vsevolod Stakhov <vsevolod@highsecure.ru>
Date: Fri, 21 Apr 2017 10:08:31 +0100
Subject: [PATCH] [Feature] Allow to have a stack of watcher finalisers

---
 src/libserver/events.c | 88 +++++++++++++++++++++++++++++++-----------
 src/libserver/events.h |  8 ++++
 2 files changed, 74 insertions(+), 22 deletions(-)

diff --git a/src/libserver/events.c b/src/libserver/events.c
index 8a3d0738d..6021f0a39 100644
--- a/src/libserver/events.c
+++ b/src/libserver/events.c
@@ -15,6 +15,7 @@
  */
 #include "config.h"
 #include "rspamd.h"
+#include "contrib/uthash/utlist.h"
 #include "events.h"
 #include "cryptobox.h"
 
@@ -41,9 +42,14 @@
         G_STRFUNC, \
         __VA_ARGS__)
 
-struct rspamd_async_watcher {
+struct rspamd_watch_stack {
 	event_watcher_t cb;
 	gpointer ud;
+	struct rspamd_watch_stack *next;
+};
+
+struct rspamd_async_watcher {
+	struct rspamd_watch_stack *st;
 	guint remain;
 	gint id;
 };
@@ -154,6 +160,19 @@ rspamd_session_add_event (struct rspamd_async_session *session,
 		g_quark_to_string (subsystem));
 }
 
+static inline void
+rspamd_session_call_watcher_stack (struct rspamd_async_session *session,
+		struct rspamd_async_watcher *w)
+{
+	struct rspamd_watch_stack *st;
+
+	LL_FOREACH (w->st, st) {
+		st->cb (session->user_data, st->ud);
+	}
+
+	w->st = NULL;
+}
+
 void
 rspamd_session_remove_event (struct rspamd_async_session *session,
 	event_finalizer_t fin,
@@ -182,7 +201,7 @@ rspamd_session_remove_event (struct rspamd_async_session *session,
 	if (found_ev->w) {
 		if (found_ev->w->remain > 0) {
 			if (--found_ev->w->remain == 0) {
-				found_ev->w->cb (session->user_data, found_ev->w->ud);
+				rspamd_session_call_watcher_stack (session, found_ev->w);
 			}
 		}
 	}
@@ -278,19 +297,23 @@ rspamd_session_watch_start (struct rspamd_async_session *session,
 		event_watcher_t cb,
 		gpointer ud)
 {
+	struct rspamd_watch_stack *st_elt;
+
 	g_assert (session != NULL);
 	g_assert (!RSPAMD_SESSION_IS_WATCHING (session));
 
 	if (session->cur_watcher == NULL) {
-		session->cur_watcher = rspamd_mempool_alloc (session->pool,
+		session->cur_watcher = rspamd_mempool_alloc0 (session->pool,
 				sizeof (*session->cur_watcher));
+		session->flags |= RSPAMD_SESSION_FLAG_WATCHING;
 	}
 
-	session->cur_watcher->cb = cb;
-	session->cur_watcher->remain = 0;
-	session->cur_watcher->ud = ud;
+	st_elt = rspamd_mempool_alloc (session->pool, sizeof (*st_elt));
+	st_elt->cb = cb;
+	st_elt->ud = ud;
+	LL_PREPEND (session->cur_watcher->st, st_elt);
+
 	session->cur_watcher->id = id;
-	session->flags |= RSPAMD_SESSION_FLAG_WATCHING;
 }
 
 guint
@@ -333,31 +356,52 @@ rspamd_session_events_pending (struct rspamd_async_session *session)
 	return npending;
 }
 
-void
-rspamd_session_watcher_push (struct rspamd_async_session *session)
+inline void
+rspamd_session_watcher_push_callback (struct rspamd_async_session *session,
+		struct rspamd_async_watcher *w,
+		event_watcher_t cb,
+		gpointer ud)
 {
+	struct rspamd_watch_stack *st;
+
 	g_assert (session != NULL);
 
-	if (RSPAMD_SESSION_IS_WATCHING (session)) {
-		session->cur_watcher->remain ++;
+	if (w == NULL) {
+		if (RSPAMD_SESSION_IS_WATCHING (session)) {
+			w = session->cur_watcher;
+		}
+		else {
+			return;
+		}
+	}
+
+	if (w) {
+		w->remain ++;
 		msg_debug_session ("push session, watcher: %d, %d events",
-				session->cur_watcher->id,
-				session->cur_watcher->remain);
+				w->id,
+				w->remain);
+
+		if (cb) {
+			st = rspamd_mempool_alloc (session->pool, sizeof (*st));
+			st->cb = cb;
+			st->ud = ud;
+
+			LL_PREPEND (w->st, st);
+		}
 	}
 }
 
+void
+rspamd_session_watcher_push (struct rspamd_async_session *session)
+{
+	rspamd_session_watcher_push_callback (session, NULL, NULL, NULL);
+}
+
 void
 rspamd_session_watcher_push_specific (struct rspamd_async_session *session,
 		struct rspamd_async_watcher *w)
 {
-	g_assert (session != NULL);
-
-	if (w) {
-		w->remain ++;
-		msg_debug_session ("push specific, watcher: %d, %d events",
-				w->id,
-				w->remain);
-	}
+	rspamd_session_watcher_push_callback (session, w, NULL, NULL);
 }
 
 void
@@ -371,7 +415,7 @@ rspamd_session_watcher_pop (struct rspamd_async_session *session,
 				w->remain);
 
 		if (--w->remain == 0) {
-			w->cb (session->user_data, w->ud);
+			rspamd_session_call_watcher_stack (session, w);
 		}
 	}
 }
diff --git a/src/libserver/events.h b/src/libserver/events.h
index 71854f205..1c9b49faf 100644
--- a/src/libserver/events.h
+++ b/src/libserver/events.h
@@ -111,6 +111,14 @@ guint rspamd_session_watch_stop (struct rspamd_async_session *s);
  */
 void rspamd_session_watcher_push (struct rspamd_async_session *s);
 
+/**
+ * Push callback to the watcher specified
+ */
+void rspamd_session_watcher_push_callback (struct rspamd_async_session *s,
+		struct rspamd_async_watcher *w,
+		event_watcher_t cb,
+		gpointer ud);
+
 /**
  * Increase refcount for a specific watcher
  */
-- 
2.39.5