X-Git-Url: http://git.cielonegro.org/gitweb.cgi?a=blobdiff_plain;f=Database%2FRRDtool%2FCreate.hs;h=28c0bfd357dc77ca5d81a0bb42985b07b6b4a54c;hb=256aad40f96ce034bc1aebd3302ecd8a86419163;hp=a3b51e54171d74e14d1ad822ece4fd8281a0c870;hpb=57b97113a93d366f14278a12b8170a1c06e258a1;p=hs-rrdtool.git

diff --git a/Database/RRDtool/Create.hs b/Database/RRDtool/Create.hs
index a3b51e5..28c0bfd 100644
--- a/Database/RRDtool/Create.hs
+++ b/Database/RRDtool/Create.hs
@@ -1,3 +1,13 @@
+{-# LANGUAGE
+  ExistentialQuantification,
+  FlexibleContexts,
+  FlexibleInstances,
+  MultiParamTypeClasses,
+  OverlappingInstances,
+  TypeFamilies,
+  UndecidableInstances
+  #-}
+{-# LANGUAGE QuasiQuotes #-} -- DELETE THIS
 module Database.RRDtool.Create
     ( DataSource
     , ExternalDSType(..)
@@ -6,7 +16,7 @@ module Database.RRDtool.Create
     , createRRD
 
     -- Data.HList
-    , (.*.)    
+    , (.&.)
     , HNil(..)
 
     -- Database.RRDtool.Expression
@@ -25,9 +35,11 @@ module Database.RRDtool.Create
     where
 
 import Data.HList
+import Data.HList.Graph
 import Data.Time.Clock
 import Data.Time.Clock.POSIX
 import Database.RRDtool.Expression
+import Types.Data.Bool
 
 
 -- |A single RRD can accept input from several data sources (DS), for
@@ -54,7 +66,8 @@ import Database.RRDtool.Expression
 -- 32bit counter, DERIVE with @'dsMin' = 0@ is probably preferable. If
 -- you are using a 64bit counter, just about any max setting will
 -- eliminate the possibility of mistaking a reset for a counter wrap.
-class DataSource ds
+class DataSource ds where
+    type DSName ds
 
 data ExternalDSType
     = GAUGE    -- ^GAUGE is for things like temperatures or number of
@@ -86,14 +99,12 @@ data ExternalDSType
                -- number of messages since the last update.
     deriving (Show, Eq, Ord)
 
-instance DataSource ExternalDSType
-
-data ExternalDataSource
+data ExternalDataSource vn
     = ExternalDataSource {
         -- |The name you will use to reference this particular data
         -- source from an RRD. A ds name must be 1 to 19 characters
         -- long in the characters @[a-zA-Z0-9_]@.
-        edsName :: !String
+        edsName :: !vn
         -- |The type of this data source.
       , edsType :: !ExternalDSType
         -- |Defines the maximum number of seconds that may pass
@@ -119,6 +130,13 @@ data ExternalDataSource
       }
     deriving (Show, Eq, Ord)
 
+instance ( IsVarName vn ~ True
+         )
+    => DataSource (ExternalDataSource vn)
+    where
+      type DSName (ExternalDataSource vn) = vn
+
+type instance MentionedVars (ExternalDataSource vn) = HNil
 
 -- |ComputedDataSource is for storing the result of a formula applied
 -- to other data sources in the RRD. This data source is not supplied
@@ -131,10 +149,10 @@ data ExternalDataSource
 -- \"computed\" columns.
 --
 -- FIXME: doc links
-data ComputedDataSource e
+data ComputedDataSource vn e
     = ComputedDataSource {
         -- |See 'edsName'
-        cdsName :: !String
+        cdsName :: !vn
         -- |rpn-expression defines the formula used to compute the
         -- PDPs of a COMPUTE data source from other data sources in
         -- the same \<RRD\>. It is similar to defining a CDEF argument
@@ -152,32 +170,112 @@ data ComputedDataSource e
     }
     deriving (Show, Eq, Ord)
 
-instance IsCommonExpr e => DataSource (ComputedDataSource e)
+instance ( IsVarName vn ~ True
+         , IsCommonExpr e ~ True
+         )
+    => DataSource (ComputedDataSource vn e)
+    where
+      type DSName (ComputedDataSource vn e) = vn
 
+type instance MentionedVars (ComputedDataSource vn e) = MentionedVars e
 
+{-
 dsTest = ComputedDataSource {
            cdsName = "foo"
---       , dsExpr = Previous :<: Const 100
---       , dsExpr = Var "foo" :<: Const 100
+--         , cdsExpr = Previous :<: Const 100
+--         , cdsExpr = Var "foo" :<: Const 100
          , cdsExpr = AverageOf (Const 100 .*. Const 200 .*. HNil)
          }
+-}
+
+-- |The name of the RRD you want to create. RRD files should end with
+-- the extension @.rrd@. However, RRDtool will accept any filename.
+newtype RRDPath = RRDPath FilePath
+
+-- |Do not clobber an existing file of the same name.
+data KeepOldRRD = KeepOldRRD
+
+-- |Specifies the time in seconds since @1970-01-01 UTC@ when the
+-- first value should be added to the RRD. RRDtool will not accept any
+-- data timed before or at the time specified. (default: @now - 10s@)
+newtype RRDStartTime = RRDStartTime POSIXTime
+
+-- |Specifies the base interval in seconds with which data will be fed
+-- into the RRD. (default: 300 sec)
+newtype RRDInterval = RRDInterval NominalDiffTime
+
+class RRDSpec s
+instance ( HOccurs    RRDPath        s
+         , HOccursOpt KeepOldRRD     s
+         , HOccursOpt RRDStartTime   s
+         , HOccursOpt RRDInterval    s
+         , HOccurs    RRDDataSources s
+         )
+    => RRDSpec s
+
+class NonEmptyDSList l
+instance ( DSList l
+         , DataSource d
+         )
+    => NonEmptyDSList (HCons d l)
+
+class DSList l
+instance DSList HNil
+instance ( DSList l
+         , DataSource d
+         )
+    => DSList (HCons d l)
+
+data RRDDataSources
+    = forall l.
+      ( NonEmptyDSList l
+      , HGraph l -- FIXME: this constraint is too weak
+      )
+    => RRDDataSources l
+
+-- RRDDataSources is a graph.
+instance ( DSList g
+         , HNodeSet g
+         , HNoDuplicates (HMap HNodeIDA g)
+         )
+    => HGraph g
+    where
+      type HNodes g = g
+
+instance ( HNodeIDSet (MentionedVars d)
+         , DataSource d
+         )
+    => HNode d
+    where
+      type HNodeID d    = DSName d
+      type HLinksFrom d = MentionedVars d
 
 -- |The 'createRRD' function lets you set up new Round Robin Database
 -- (RRD) files. The file is created at its final, full size and filled
 -- with @*UNKNOWN*@ data.
-createRRD
-    :: FilePath -- ^The name of the RRD you want to create. RRD files
-                -- should end with the extension @.rrd@. However,
-                -- RRDtool will accept any filename.
-    -> Bool -- ^Do not clobber an existing file of the same name.
-    -> Maybe POSIXTime -- ^Specifies the time in seconds since
-                       -- @1970-01-01 UTC@ when the first value should
-                       -- be added to the RRD. RRDtool will not accept
-                       -- any data timed before or at the time
-                       -- specified. (default: @now - 10s@)
-    -> Maybe NominalDiffTime -- ^Specifies the base interval in
-                             -- seconds with which data will be fed
-                             -- into the RRD. (default: 300 sec)
---    -> [DataSource] -- ^Data sources to accept input from.
-    -> IO ()
+createRRD :: ( RRDSpec s
+             )
+            => s -> IO ()
 createRRD = error "FIXME"
+
+testMain :: IO ()
+testMain = let s = RRDPath "test.rrd" .&.
+                   KeepOldRRD         .&.
+                   RRDDataSources testDSList .&.
+                   HNil
+           in
+             createRRD s
+
+testDSList = let a = ComputedDataSource {
+                       cdsName = [$hString|foo|]
+                     , cdsExpr = Var [$hString|bar|]
+                     }
+                 b = ComputedDataSource {
+                       cdsName = [$hString|bar|]
+                     , cdsExpr = Var [$hString|foo|] -- shouldn't typecheck!
+                     }
+                 c = ComputedDataSource {
+                       cdsName = [$hString|baz|]
+                     , cdsExpr = Var [$hString|foo|] -- should typecheck!
+                     }
+             in a .&. b .&. HNil
\ No newline at end of file