Implemented the clean killing of plugins' threads.

Hsbot/Plugin.hs

@@ -1,11 +1,16 @@
 module Hsbot.Plugin
-    ( spawnIrcPlugins
+    ( killPlugin
+    , spawnIrcPlugins
+    , spawnIrcPlugin
+    , unloadPlugin
     ) where
 
 import Control.Concurrent
 import Control.Concurrent.Chan ()
+import Control.Exception
 import Control.Monad.State
 import qualified Data.Map as M
+import Prelude hiding (catch)
 
 import Hsbot.Config
 import Hsbot.Irc.Config
@@ -17,16 +22,37 @@ spawnIrcPlugins :: Bot ()
 spawnIrcPlugins = do
     config <- gets botConfig
     mapM_ (spawnIrcPlugin) (ircConfigs config)
-  where
-    spawnIrcPlugin :: IrcConfig -> Bot ()
-    spawnIrcPlugin config = do
-        bot <- get
-        let chan  = botChan bot
-        pchan <- liftIO (newChan :: IO (Chan BotMsg))
-        threadId <- liftIO $ forkIO (startIrcbot config chan pchan)
-        let plugin  = PluginState { pluginName    = ircConfigName config
-                                  , pluginChan    = pchan
-                                  , pluginHandles = M.empty }
-            plugins = botPlugins bot
-        put $ bot { botPlugins = M.insert (pluginName plugin) (plugin, threadId) plugins }
+
+-- | spawns a single irc plugin
+spawnIrcPlugin :: IrcConfig -> Bot ()
+spawnIrcPlugin config = do
+    bot <- get
+    let chan  = botChan bot
+    pchan <- liftIO (newChan :: IO (Chan BotMsg))
+    threadId <- liftIO $ forkIO (startIrcbot config chan pchan)
+    let plugin  = PluginState { pluginName    = ircConfigName config
+                              , pluginChan    = pchan
+                              , pluginHandles = M.empty }
+        plugins = botPlugins bot
+    put $ bot { botPlugins = M.insert (pluginName plugin) (plugin, threadId) plugins }
+
+-- | Unloads a plugin
+unloadPlugin :: String -> Bot ()
+unloadPlugin name = do
+    killPlugin name
+    resumeData <- gets botResumeData
+    liftIO $ modifyMVar_ resumeData (\oldData -> return $ M.delete name oldData)
+
+-- | kills a plugin
+killPlugin :: String -> Bot ()
+killPlugin name = do
+    bot <- get
+    let oldPlugins = botPlugins bot
+    -- We check if the plugin exists
+    case M.lookup name oldPlugins of
+        Just (_, threadId) -> do
+            let newPlugins = M.delete name oldPlugins
+            liftIO $ throwTo threadId UserInterrupt
+            put $ bot { botPlugins = newPlugins }
+        Nothing            -> return ()