From 488b8e05f95fc16c32b99880538c544a23a0088a Mon Sep 17 00:00:00 2001
From: Matt Mullins <mmullins@mmlx.us>
Date: Mon, 12 Dec 2011 22:30:36 -0800
Subject: [PATCH] Limit IRC reconnects to once every 30 seconds.

And I also fixed another bug that made reconnects fail anyway.
---
 irc/irc.app         |  4 ++--
 irc/irc_conn.erl    | 19 +++++++++++++++++++
 irc/irc_net_sup.erl |  6 +++++-
 3 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/irc/irc.app b/irc/irc.app
index 402232c..25720a8 100644
--- a/irc/irc.app
+++ b/irc/irc.app
@@ -1,9 +1,9 @@
 {application, irc,
  [{description, "IRC protocol application"},
-  {vsn, "5"},
+  {vsn, "6"},
   {modules, [irc_util, irc_app, irc_sup, irc_net_sup, irc_conn,
              irc_object_sup, irc_amqp_listener, irc_command]},
-  {registered, [irc_sup]},
+  {registered, [irc_sup, irc_dummy]},
   {applications, [core, amqp]},
   {mod, {irc_app, []}}
  ]}.
diff --git a/irc/irc_conn.erl b/irc/irc_conn.erl
index 5548932..643f967 100644
--- a/irc/irc_conn.erl
+++ b/irc/irc_conn.erl
@@ -2,6 +2,8 @@
 -behavior(gen_server).
 -vsn(2).
 
+-define(RECONNECT_TIME, 30000).
+
 -export([
           start_link/3,
           send_command/2
@@ -38,6 +40,23 @@ send_command(Pid, Command) ->
 init({Instance, Supervisor, TableId}) ->
     ets:insert(TableId, {irc_conn_pid, self()}), % record the connection PID in the table
 
+    % The reconnect_timer sends a dummy message to a process that does not exist,
+    % simply so that we can read whether it has fired or not.  This lets us prevent
+    % reconnecting to the server too quickly.
+    case ets:lookup(TableId, reconnect_timer) of
+        [{reconnect_timer, TimerId}] ->
+            case erlang:read_timer(TimerId) of
+                false -> ok;
+                Millis ->
+                    % sleep that long in this process, since the process that set
+                    % the timer is long dead.
+                    timer:sleep(Millis)
+            end;
+        [] -> ok
+    end,
+    NewTimerId = erlang:start_timer(?RECONNECT_TIME, irc_dummy, ok),
+    ets:insert(TableId, {reconnect_timer, NewTimerId}),
+
     gen_server:cast(self(), create_object_sup), % This process is tasked with creating
                                                 % the irc_object_sup, but we defer until
                                                 % after init() finishes to avoid deadlock
diff --git a/irc/irc_net_sup.erl b/irc/irc_net_sup.erl
index b456a4a..bf81d24 100644
--- a/irc/irc_net_sup.erl
+++ b/irc/irc_net_sup.erl
@@ -45,7 +45,11 @@ create_object_sup(Instance, Supervisor, TableId) ->
                  supervisor,
                  [irc_object_sup]
                 },
-    {ok, ObjectSupPid} = supervisor:start_child(Supervisor, ObjectSup),
+    % Pattern match to handle the case where the object_sup starts before irc_conn
+    case supervisor:start_child(Supervisor, ObjectSup) of
+        {ok, ObjectSupPid} -> ok;
+        {error, {already_started, ObjectSupPid}} -> ok
+    end,
     {ok, ObjectSupPid}.
 
 %% @doc Kills the irc_object_sup running under this supervisor
-- 
2.11.0