From c2c904f57aedbf048e445c39fed43b37ee60f4b1 Mon Sep 17 00:00:00 2001
From: Ramakrishnan Muthukrishnan <ram@rkrishnan.org>
Date: Mon, 30 Mar 2015 14:27:36 +0530
Subject: [PATCH] combine announce and announceList slots in the Metainfo
 record.

This eliminates the unnecessary "getter" function getTrackers
and simplifies the code a bit. Still a work in progress.
---
 src/FuncTorrent.hs          |  2 +-
 src/FuncTorrent/Bencode.hs  |  6 ++++++
 src/FuncTorrent/Metainfo.hs | 21 ++++++++-------------
 src/Main.hs                 |  4 ++--
 4 files changed, 17 insertions(+), 16 deletions(-)

diff --git a/src/FuncTorrent.hs b/src/FuncTorrent.hs
index e5f9b5c..2841c13 100644
--- a/src/FuncTorrent.hs
+++ b/src/FuncTorrent.hs
@@ -5,7 +5,7 @@ module FuncTorrent
      Metainfo,
      Peer,
      PeerResp(..),
-     announce,
+     announceList,
      connect,
      decode,
      encode,
diff --git a/src/FuncTorrent/Bencode.hs b/src/FuncTorrent/Bencode.hs
index 8ea530a..96600e2 100644
--- a/src/FuncTorrent/Bencode.hs
+++ b/src/FuncTorrent/Bencode.hs
@@ -2,6 +2,7 @@
 module FuncTorrent.Bencode
     (BVal(..),
      InfoDict,
+     bstrToString,
      encode,
      decode
     ) where
@@ -139,3 +140,8 @@ encode (Bstr bs) = pack $ show (length bs) ++ ":" ++ unpack bs
 encode (Bint i) = pack $ "i" ++ show i ++ "e"
 encode (Blist xs) = pack $ "l" ++ unpack (concat $ map encode xs) ++ "e"
 encode (Bdict d) = concat [concat ["d", encode . Bstr . pack $ k , encode (d ! k) , "e"] | k <- keys d]
+
+-- getters
+bstrToString :: BVal -> Maybe String
+bstrToString (Bstr s) = Just $ unpack s
+bstrToString _ = Nothing
diff --git a/src/FuncTorrent/Metainfo.hs b/src/FuncTorrent/Metainfo.hs
index 1fd9475..9ff3ce3 100644
--- a/src/FuncTorrent/Metainfo.hs
+++ b/src/FuncTorrent/Metainfo.hs
@@ -1,20 +1,19 @@
 module FuncTorrent.Metainfo
     (Info,
      Metainfo,
+     announceList,
      mkMetaInfo,
      mkInfo,
-     announce,
      lengthInBytes,
      info,
      name,
-     getTrackers
     ) where
 
 import Prelude hiding (lookup)
 import Data.ByteString.Char8 (ByteString, unpack)
 import Data.Map as M ((!), lookup)
 
-import FuncTorrent.Bencode (BVal(..))
+import FuncTorrent.Bencode (BVal(..), bstrToString)
 
 -- only single file mode supported for the time being.
 data Info = Info { pieceLength :: !Integer
@@ -26,7 +25,6 @@ data Info = Info { pieceLength :: !Integer
                  } deriving (Eq, Show)
 
 data Metainfo = Metainfo { info :: !Info
-                         , announce :: !(Maybe String)
                          , announceList :: ![String]
                          , creationDate :: !(Maybe String)
                          , comment :: !(Maybe String)
@@ -64,10 +62,8 @@ mkMetaInfo (Bdict m) = let (Just info') = mkInfo $ m ! "info"
                            createdBy' = lookup "created by" m
                            encoding' = lookup "encoding" m
                        in Just Metainfo { info = info'
-                                        , announce = announce'
-                                                     >>= (\(Bstr a) ->
-                                                           Just (unpack a))
-                                        , announceList = getAnnounceList announceList'
+                                        , announceList = maybeToList (announce' >>= bstrToString)
+                                                         ++ getAnnounceList announceList'
                                         , creationDate = creationDate'
                                         , comment = maybeBstrToString comment'
                                         , createdBy = maybeBstrToString createdBy'
@@ -75,6 +71,10 @@ mkMetaInfo (Bdict m) = let (Just info') = mkInfo $ m ! "info"
                                         }
 mkMetaInfo _ = Nothing
 
+maybeToList :: Maybe a -> [a]
+maybeToList  Nothing   = []
+maybeToList  (Just x)  = [x]
+
 getAnnounceList :: Maybe BVal -> [String]
 getAnnounceList Nothing = []
 getAnnounceList (Just (Bint _)) = []
@@ -87,8 +87,3 @@ getAnnounceList (Just (Blist l)) = map (\s -> case s of
                                                _ -> "") l
 
 getAnnounceList (Just (Bdict _)) = []
-
-getTrackers :: Metainfo -> [String]
-getTrackers m = case announce m of
-                 Nothing -> announceList m
-                 Just a -> a : announceList m
diff --git a/src/Main.hs b/src/Main.hs
index c1b3668..cfbcfe3 100644
--- a/src/Main.hs
+++ b/src/Main.hs
@@ -10,7 +10,7 @@ import Text.ParserCombinators.Parsec (ParseError)
 
 import FuncTorrent.Bencode (decode, BVal(..))
 import FuncTorrent.Logger (initLogger, logMessage, logStop)
-import FuncTorrent.Metainfo (lengthInBytes, mkMetaInfo, info, name, getTrackers)
+import FuncTorrent.Metainfo (lengthInBytes, mkMetaInfo, info, name, announceList)
 import FuncTorrent.Peer (peers, mkPeerResp, handShakeMsg)
 import FuncTorrent.Tracker (connect, prepareRequest)
 
@@ -51,7 +51,7 @@ main = do
 
               let len = lengthInBytes $ info m
                   (Bdict d') = d
-                  trackers = getTrackers m
+                  trackers = announceList m
 
               logMsg "Trying to fetch peers: "
               response <- connect (head trackers) (prepareRequest d' peerId len)
-- 
2.37.2