# HG changeset patch
# User Kim Alvefur <zash@zash.se>
# Date 1618010162 -7200
# Node ID 591c643d55b2c5b84f309d48ca06dcf86e6f7989
# Parent  53ee391ca6893e48d6237e70298b8db8d1b07e37
mod_storage_xmlarchive: Insert micropauses in long-running queries

Allows other processing to be interleaved with long-running queries.

Drops 0.9 support since it requires util.async, but 0.9 really should be
EOL by now.

diff -r 53ee391ca689 -r 591c643d55b2 mod_storage_xmlarchive/README.markdown
--- a/mod_storage_xmlarchive/README.markdown	Thu Apr 01 11:35:26 2021 +0200
+++ b/mod_storage_xmlarchive/README.markdown	Sat Apr 10 01:16:02 2021 +0200
@@ -48,9 +48,8 @@
   ------ ---------------
   trunk  Should work
   0.11   Works
-  0.10   Works
-  0.9    Should work
-  0.8    Does not work
+  0.10   Should work
+  0.9    Does not work
   ------ ---------------
 
 Conversion to or from internal storage
diff -r 53ee391ca689 -r 591c643d55b2 mod_storage_xmlarchive/mod_storage_xmlarchive.lua
--- a/mod_storage_xmlarchive/mod_storage_xmlarchive.lua	Thu Apr 01 11:35:26 2021 +0200
+++ b/mod_storage_xmlarchive/mod_storage_xmlarchive.lua	Sat Apr 10 01:16:02 2021 +0200
@@ -12,6 +12,7 @@
 local dt = require"util.datetime";
 local new_stream = require "util.xmppstream".new;
 local xml = require "util.xml";
+local async = require "util.async";
 local empty = {};
 
 if not dm.append_raw then
@@ -130,10 +131,25 @@
 	return ok, err;
 end
 
+local function get_nexttick()
+	if async.ready() then
+		return function ()
+			-- slow down
+			local wait, done = async.waiter();
+			module:add_timer(0, done);
+			wait();
+		end
+	else
+		-- no async, no-op
+		return function () end
+	end
+end
+
 function archive:_get_idx(username, id, dates)
 	module:log("debug", "Looking for item with id %q", id);
 	dates = dates or self:dates(username) or empty;
 	local date = id:match("^%d%d%d%d%-%d%d%-%d%d");
+	local tick = get_nexttick();
 	for d = 1, #dates do
 		if not date or date == dates[d] then
 			module:log("debug", "Loading index for %s", dates[d]);
@@ -151,6 +167,9 @@
 			module:log("debug", "Skipping remaining dates after %s", date);
 			return; -- List is assumed to be sorted
 		end
+
+		-- insert pauses to allow other processing
+		if d % 14 == 0 then tick(); end
 	end
 	module:log("debug", "Item not found");
 end
@@ -261,6 +280,8 @@
 		return xmlfile:read(length);
 	end
 
+	local tick = get_nexttick();
+
 	return function ()
 		if limit and count >= limit then if xmlfile then xmlfile:close() end return; end
 		for d = start_day, last_day, step do
@@ -319,6 +340,8 @@
 				xmlfile:close();
 				xmlfile = nil;
 			end
+			-- If we're running through a lot of day-files then lets allow for other processing between each day
+			tick();
 		end
 	end
 end