# HG changeset patch
# User Kim Alvefur <zash@zash.se>
# Date 1485042071 -3600
# Node ID dc30ca5ce315c161b3a87ecad2c615a4283b1718
# Parent  51cf82d36a8a75a2279ce5eb10e726b949394fb6
mod_csi_pump: Lossless CSI mode

diff -r 51cf82d36a8a -r dc30ca5ce315 mod_csi_pump/README.markdown
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mod_csi_pump/README.markdown	Sun Jan 22 00:41:11 2017 +0100
@@ -0,0 +1,9 @@
+---
+description: Lossless CSI module
+---
+
+Stanzas are queued in a buffer until either an "important" stanza is
+encountered or the buffer becomes full. Then all queued stanzas are sent
+at the same time. This way, nothing is lost or reordered while still
+allowing for power usage savings by not requiring mobile clients to
+bring up their radio for unimportant stanzas.
diff -r 51cf82d36a8a -r dc30ca5ce315 mod_csi_pump/mod_csi_pump.lua
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mod_csi_pump/mod_csi_pump.lua	Sun Jan 22 00:41:11 2017 +0100
@@ -0,0 +1,96 @@
+-- Copyright (C) 2016 Kim Alvefur
+--
+
+module:depends"csi"
+module:depends"track_muc_joins"
+local jid = require "util.jid";
+local new_queue = require "util.queue".new;
+
+local function new_pump(output, ...)
+	-- luacheck: ignore 212/self
+	local q = new_queue(...);
+	local flush = true;
+	function q:pause()
+		flush = false;
+	end
+	function q:resume()
+		flush = true;
+		return q:flush();
+	end
+	local push = q.push;
+	function q:push(item)
+		local ok = push(self, item);
+		if not ok then
+			q:flush();
+			output(item, self);
+		elseif flush then
+			return q:flush();
+		end
+		return true;
+	end
+	function q:flush()
+		local item = self:pop();
+		while item do
+			output(item, self);
+			item = self:pop();
+		end
+		return true;
+	end
+	return q;
+end
+
+-- TODO delay stamps
+-- local dt = require "util.datetime";
+
+local function is_important(stanza, session)
+	local st_name = stanza.name;
+	if not st_name then return false; end
+	local st_type = stanza.attr.type;
+	if st_name == "presence" then
+		-- TODO check for MUC status codes?
+		return false;
+	elseif st_name == "message" then
+		if st_type == "headline" then
+			return false;
+		end
+		local body = stanza:get_child_text("body");
+		if not body then return false; end
+		if st_type == "groupchat" then
+			if body:find(session.username, 1, true) then return true; end
+			local rooms = session.rooms_joined;
+			if not rooms then return false; end
+			local room_nick = rooms[jid.bare(stanza.attr.from)];
+			if room_nick and body:find(room_nick, 1, true) then return true; end
+			return false;
+		end
+		return body;
+	end
+	return true;
+end
+
+module:hook("csi-client-inactive", function (event)
+	local session = event.origin;
+	if session.pump then
+		session.pump:pause();
+	else
+		session._orig_send = session.send;
+		local pump = new_pump(session.send, 100);
+		pump:pause();
+		session.pump = pump;
+		function session.send(stanza)
+			pump:push(stanza);
+			if is_important(stanza, session) then
+				pump:flush();
+			end
+			return true;
+		end
+	end
+end);
+
+module:hook("csi-client-active", function (event)
+	local session = event.origin;
+	if session.pump then
+		session.pump:resume();
+	end
+end);
+