mod_c2s, mod_s2s: Support for queuing callbacks to run in session thread

This allows certain session-specific code that needs to run in the async
context, but is itself triggered outside of that context (e.g. timers), to
be queued.

An example of this is the session destruction code of mod_smacks, when the
hibernation timeout is reached.

2 files changed, 32 insertions, 23 deletions

diff --git a/plugins/mod_c2s.lua b/plugins/mod_c2s.lua
index 09d4be08..e29ea6a0 100644
--- a/plugins/mod_c2s.lua
+++ b/plugins/mod_c2s.lua
@@ -45,6 +45,7 @@ local hosts = prosody.hosts;
 local stream_callbacks = { default_ns = "jabber:client" };
 local listener = {};
 local runner_callbacks = {};
+local session_events = {};
 
 local m_tls_params = module:metric(
 	"counter", "encrypted", "",
@@ -76,11 +77,11 @@ local stream_xmlns_attr = {xmlns='urn:ietf:params:xml:ns:xmpp-streams'};
 
 function stream_callbacks.streamopened(session, attr)
 	-- run _streamopened in async context
-	session.thread:run({ stream = "opened", attr = attr });
+	session.thread:run({ event = "streamopened", attr = attr });
 end
 
-function stream_callbacks._streamopened(session, attr)
-	local send = session.send;
+function session_events.streamopened(session, event)
+	local send, attr = session.send, event.attr;
 	if not attr.to then
 		session:close{ condition = "improper-addressing",
 			text = "A 'to' attribute is required on stream headers" };
@@ -162,14 +163,19 @@ end
 
 function stream_callbacks.streamclosed(session, attr)
 	-- run _streamclosed in async context
-	session.thread:run({ stream = "closed", attr = attr });
+	session.thread:run({ event = "streamclosed", attr = attr });
 end
 
-function stream_callbacks._streamclosed(session)
+function session_events.streamclosed(session)
 	session.log("debug", "Received </stream:stream>");
 	session:close(false);
 end
 
+function session_events.callback(session, event)
+	session.log("debug", "Running session callback %s", event.name);
+	event.callback(session, event);
+end
+
 function stream_callbacks.error(session, error, data)
 	if error == "no-stream" then
 		session.log("debug", "Invalid opening stream header (%s)", (data:gsub("^([^\1]+)\1", "{%1}")));
@@ -350,13 +356,11 @@ function listener.onconnect(conn)
 		session.stream:reset();
 	end
 
-	session.thread = runner(function (stanza)
-		if st.is_stanza(stanza) then
-			core_process_stanza(session, stanza);
-		elseif stanza.stream == "opened" then
-			stream_callbacks._streamopened(session, stanza.attr);
-		elseif stanza.stream == "closed" then
-			stream_callbacks._streamclosed(session, stanza.attr);
+	session.thread = runner(function (item)
+		if st.is_stanza(item) then
+			core_process_stanza(session, item);
+		else
+			session_events[item.event](session, item);
 		end
 	end, runner_callbacks, session);
 
diff --git a/plugins/mod_s2s.lua b/plugins/mod_s2s.lua
index 638ace3d..8eb1565e 100644
--- a/plugins/mod_s2s.lua
+++ b/plugins/mod_s2s.lua
@@ -89,6 +89,7 @@ local m_tls_params = module:metric(
 local sessions = module:shared("sessions");
 
 local runner_callbacks = {};
+local session_events = {};
 
 local listener = {};
 
@@ -469,10 +470,11 @@ local xmlns_xmpp_streams = "urn:ietf:params:xml:ns:xmpp-streams";
 
 function stream_callbacks.streamopened(session, attr)
 	-- run _streamopened in async context
-	session.thread:run({ stream = "opened", attr = attr });
+	session.thread:run({ event = "streamopened", attr = attr });
 end
 
-function stream_callbacks._streamopened(session, attr)
+function session_events.streamopened(session, event)
+	local attr = event.attr;
 	session.version = tonumber(attr.version) or 0;
 	session.had_stream = true; -- Had a stream opened at least once
 
@@ -613,14 +615,19 @@ function stream_callbacks._streamopened(session, attr)
 	end
 end
 
-function stream_callbacks._streamclosed(session)
+function session_events.streamclosed(session)
 	(session.log or log)("debug", "Received </stream:stream>");
 	session:close(false);
 end
 
+function session_events.callback(session, event)
+	session.log("debug", "Running session callback %s", event.name);
+	event.callback(session, event);
+end
+
 function stream_callbacks.streamclosed(session, attr)
 	-- run _streamclosed in async context
-	session.thread:run({ stream = "closed", attr = attr });
+	session.thread:run({ event = "streamclosed", attr = attr });
 end
 
 -- Some stream conditions indicate a problem on our end, e.g. that we sent
@@ -784,13 +791,11 @@ end
 local function initialize_session(session)
 	local stream = new_xmpp_stream(session, stream_callbacks, stanza_size_limit);
 
-	session.thread = runner(function (stanza)
-		if st.is_stanza(stanza) then
-			core_process_stanza(session, stanza);
-		elseif stanza.stream == "opened" then
-			stream_callbacks._streamopened(session, stanza.attr);
-		elseif stanza.stream == "closed" then
-			stream_callbacks._streamclosed(session, stanza.attr);
+	session.thread = runner(function (item)
+		if st.is_stanza(item) then
+			core_process_stanza(session, item);
+		else
+			session_events[item.event](session, item);
 		end
 	end, runner_callbacks, session);