X-Git-Url: http://gitweb.michael.orlitzky.com/?p=dead%2Fharbl.git;a=blobdiff_plain;f=harbl-cli%2Fsrc%2FOptionalConfiguration.hs;h=37d05a9431af2bb44e8f862691e936b1f627e8d5;hp=35ca7d4cb3a7876648f329dbee2e1ff69def59b9;hb=98b9d8768fe78d9948151e499ec52f7f616bd6e9;hpb=b47aaa60a797aee4ecdcd5535ed40c1a7b15ddce

diff --git a/harbl-cli/src/OptionalConfiguration.hs b/harbl-cli/src/OptionalConfiguration.hs
index 35ca7d4..37d05a9 100644
--- a/harbl-cli/src/OptionalConfiguration.hs
+++ b/harbl-cli/src/OptionalConfiguration.hs
@@ -11,6 +11,8 @@
 --
 module OptionalConfiguration (
   OptionalConfiguration(..),
+  merge_maybe,
+  merge_monoid,
   from_rc )
 where
 
@@ -30,6 +32,9 @@ import System.FilePath ( (</>) )
 import System.IO.Error ( catchIOError )
 import System.IO ( hPutStrLn, stderr )
 
+-- Harbl library imports.
+import Network.DNS.RBL.Weight ( Weight )
+
 -- Local imports.
 import Hosts ( Hosts(..) )
 import Lists ( Lists(..) )
@@ -43,10 +48,88 @@ import Lists ( Lists(..) )
 data OptionalConfiguration =
   OptionalConfiguration {
     hosts :: Hosts,
-    lists :: Lists }
+    lists :: Lists,
+    threshold :: Maybe Weight }
     deriving (Show, Data, Typeable)
 
 
+-- | Choose a nonempty monoid from our two arguments, preferring the
+--   second. So if the second monoid is non-'mempty', we'll return
+--   that. Otherwise the first.
+--
+--   ==== _Examples_
+--
+--   The second list is preferred if both are nonempty:
+--
+--   >>> merge_monoid [1,2] [3,4]
+--   [3,4]
+--
+--   However, if the second list is empty, the first is returned:
+--
+--   >>> merge_monoid [1,2] []
+--   [1,2]
+--
+--   And if both are empty, we return the first (i.e. empty) list:
+--
+--   >>> merge_monoid [] []
+--   []
+--
+merge_monoid :: (Eq a, Monoid a) => a -> a -> a
+merge_monoid l1 l2 = if l2 == mempty then l1 else l2
+
+
+-- | Like 'merge_monoid', except for optional things. We take two
+--   (potentially 'Nothing') values, and then try to choose a
+--   non-'Nothing' one, preferring the second argument.
+--
+--   ==== _Examples_
+--
+--   The second is preferred if it is non-'Nothing':
+--
+--   >>> merge_maybes (Just 3) (Just 4)
+--   Just 4
+--
+--   >>> merge_maybes Nothing (Just 4)
+--   Just 4
+--
+--   However, if the second argument is 'Nothing', the first is
+--   returned:
+--
+--   >>> merge_maybes (Just 1) Nothing
+--   Just 1
+--
+--   If both are 'Nothing', we return 'Nothing':
+--
+--   >>> merge_maybes Nothing Nothing
+--   Nothing
+--
+merge_maybes :: (Maybe a) -> (Maybe a) -> (Maybe a)
+merge_maybes _ y@(Just _) = y
+merge_maybes x@(Just _) Nothing = x
+merge_maybes Nothing Nothing = Nothing
+
+
+-- | Return the (thing contained in the) second argument if it is
+--   non-'Nothing'. Otherwise return the first argument.
+--
+--   ==== _Examples_
+--
+--   The second is preferred if it is non-'Nothing':
+--
+--   >>> merge_maybe 3 (Just 4)
+--   4
+--
+--   However, if the second argument is 'Nothing', the first is
+--   returned:
+--
+--   >>> merge_maybe 1 Nothing
+--   1
+--
+merge_maybe :: a -> Maybe a -> a
+merge_maybe x Nothing = x
+merge_maybe _ (Just y) = y
+
+
 -- | The Monoid instance for these lets us \"combine\" two
 --   OptionalConfigurations. The \"combine\" operation that we'd like to
 --   perform is, essentially, to mash them together. So if we have two
@@ -57,18 +140,14 @@ data OptionalConfiguration =
 --
 instance Monoid OptionalConfiguration where
   -- | An empty OptionalConfiguration.
-  mempty = OptionalConfiguration (Hosts []) (Lists [])
-
+  mempty = OptionalConfiguration mempty mempty Nothing
 
   -- | Combine @cfg1@ and @cfg2@, giving precedence to @cfg2@.
-  --   XML files can only be specified on the command-line, so we
-  --   just join them together here.
-  cfg1 `mappend` cfg2 =
-    OptionalConfiguration all_hosts all_lists
+  cfg1 `mappend` cfg2 = OptionalConfiguration hs ls t
     where
-      all_hosts = Hosts $ (get_hosts $ hosts cfg1) ++ (get_hosts $ hosts cfg2)
-      all_lists = Lists $ (get_lists $ lists cfg1) ++ (get_lists $ lists cfg2)
-
+      hs = merge_monoid (hosts cfg1) (hosts cfg2)
+      ls = merge_monoid (lists cfg1) (lists cfg2)
+      t  = merge_maybes (threshold cfg1) (threshold cfg2)
 
 
 -- | Obtain an OptionalConfiguration from harblrc in either the global
@@ -93,5 +172,9 @@ from_rc = do
   cfg <- DC.load [ DC.Optional global_config_path,
                    DC.Optional user_config_path ]
   cfg_lists <- DC.lookup cfg "lists"
-  let cfg_hosts = Hosts [] -- This won't be in the config file.
-  return $ OptionalConfiguration cfg_hosts (fromMaybe def cfg_lists)
+  cfg_hosts <- DC.lookup cfg "hosts"
+  cfg_threshold <- DC.lookup cfg "threshold"
+  return $ OptionalConfiguration
+             (fromMaybe def cfg_hosts)
+             (fromMaybe def cfg_lists)
+             cfg_threshold