From e92065b9e3a4f35f6a74aaa1d138f3032ead6b52 Mon Sep 17 00:00:00 2001
From: Ramakrishnan Muthukrishnan <ram@rkrishnan.org>
Date: Sun, 4 Jun 2017 12:38:13 +0530
Subject: [PATCH] print and error and exit if called without arguments

---
 run              |  4 +++
 src/main/Main.hs | 82 +++++++++++++++++++++++++-----------------------
 2 files changed, 47 insertions(+), 39 deletions(-)
 create mode 100755 run

diff --git a/run b/run
new file mode 100755
index 0000000..4e6ac2f
--- /dev/null
+++ b/run
@@ -0,0 +1,4 @@
+#!/bin/sh
+
+./dist-newstyle/build/functorrent-0.2.0/build/FuncTorrent/functorrent $*
+
diff --git a/src/main/Main.hs b/src/main/Main.hs
index 71c9841..8fccebe 100644
--- a/src/main/Main.hs
+++ b/src/main/Main.hs
@@ -45,8 +45,8 @@ logError e logMsg = logMsg $ "parse error: \n" ++ e
 exit :: IO ByteString
 exit = exitSuccess
 
-usage :: IO ()
-usage = putStrLn "usage: functorrent torrent-file"
+usage :: String
+usage = "usage: functorrent torrent-file"
 
 parse :: [String] -> IO ByteString
 parse [] = getContents
@@ -73,40 +73,44 @@ main = do
     logR <- initLogger
     peerId <- mkPeerID    
     let log = logMessage logR
-    log "Starting up functorrent"
-    log $ "Parsing arguments " ++ concat args
-    torrentStr <- parse args
-    case torrentToMetainfo torrentStr of
-     Left e -> logError e log
-     Right m -> do
-       -- if we had downloaded the file before (partly or completely)
-       -- then we should check the current directory for the existence
-       -- of the file and then update the map of each piece' availability.
-       -- This can be done by reading each piece and verifying the checksum.
-       -- If the checksum does not match, we don't have that piece.
-       let filePath = name (info m) -- really this is just the file name, not file path
-           fileLen = lengthInBytes (info m)
-           pieceHash = pieces (info m)
-           pLen = pieceLength (info m)
-           infohash = infoHash m
-           defaultPieceMap = initPieceMap pieceHash fileLen pLen
-       log $ "create FS msg channel"
-       fsMsgChannel <- FS.createMsgChannel
-       log $ "Downloading file : " ++ filePath
-       pieceMap <- FS.pieceMapFromFile filePath fileLen defaultPieceMap
-       log $ "start filesystem manager thread"
-       fsTid <- forkIO $ withFile filePath ReadWriteMode (FS.run pieceMap fsMsgChannel)
-       log $ "starting server"
-       (serverSock, (PortNumber portnum)) <- Server.start
-       log $ "server started on " ++ show portnum
-       log "Trying to fetch peers"
-       _ <- forkIO $ Server.run serverSock peerId m pieceMap fsMsgChannel
-       log $ "Trackers: " ++ head (announceList m)
-       trackerMsgChan <- newTracker
-       _ <- forkIO $ runTracker trackerMsgChan fsMsgChannel infohash portnum peerId (announceList m) fileLen
-       ps <- getConnectedPeers trackerMsgChan
-       log $ "Peers List : " ++ (show ps)
-       let p1 = head ps
-       handlePeerMsgs p1 peerId m pieceMap True fsMsgChannel
-       logStop logR
-       killThread fsTid
+    case args of
+      [] -> do
+        log usage
+      _  -> do
+        log "Starting up functorrent"
+        log $ "Parsing arguments " ++ concat args
+        torrentStr <- parse args
+        case torrentToMetainfo torrentStr of
+          Left e -> logError e log
+          Right m -> do
+            -- if we had downloaded the file before (partly or completely)
+            -- then we should check the current directory for the existence
+            -- of the file and then update the map of each piece' availability.
+            -- This can be done by reading each piece and verifying the checksum.
+            -- If the checksum does not match, we don't have that piece.
+            let filePath = name (info m) -- really this is just the file name, not file path
+                fileLen = lengthInBytes (info m)
+                pieceHash = pieces (info m)
+                pLen = pieceLength (info m)
+                infohash = infoHash m
+                defaultPieceMap = initPieceMap pieceHash fileLen pLen
+            log $ "create FS msg channel"
+            fsMsgChannel <- FS.createMsgChannel
+            log $ "Downloading file : " ++ filePath
+            pieceMap <- FS.pieceMapFromFile filePath fileLen defaultPieceMap
+            log $ "start filesystem manager thread"
+            fsTid <- forkIO $ withFile filePath ReadWriteMode (FS.run pieceMap fsMsgChannel)
+            log $ "starting server"
+            (serverSock, (PortNumber portnum)) <- Server.start
+            log $ "server started on " ++ show portnum
+            log "Trying to fetch peers"
+            _ <- forkIO $ Server.run serverSock peerId m pieceMap fsMsgChannel
+            log $ "Trackers: " ++ head (announceList m)
+            trackerMsgChan <- newTracker
+            _ <- forkIO $ runTracker trackerMsgChan fsMsgChannel infohash portnum peerId (announceList m) fileLen
+            ps <- getConnectedPeers trackerMsgChan
+            log $ "Peers List : " ++ (show ps)
+            let p1 = head ps
+            handlePeerMsgs p1 peerId m pieceMap True fsMsgChannel
+            logStop logR
+            killThread fsTid
-- 
2.37.2