{-# LANGUAGE TemplateHaskell #-}
-{-| TemplateHaskell helper for HTools.
+{-| TemplateHaskell helper for Ganeti Haskell code.
As TemplateHaskell require that splices be defined in a separate
module, we combine all the TemplateHaskell functionality that HTools
, declareIADT
, makeJSONInstance
, genOpID
+ , genAllOpIDs
, genOpCode
, genStrOfOp
, genStrOfKey
, defaultField
, optionalField
, renameField
- , containerField
, customField
, timeStampFields
, uuidFields
, serialFields
, tagsFields
+ , TagSet
, buildObject
, buildObjectSerialisation
, buildParam
- , Container
+ , DictObject(..)
) where
-import Control.Arrow
-import Control.Monad (liftM, liftM2)
+import Control.Monad (liftM)
import Data.Char
import Data.List
-import qualified Data.Map as M
+import Data.Maybe (fromMaybe)
import qualified Data.Set as Set
import Language.Haskell.TH
import qualified Text.JSON as JSON
-import Ganeti.HTools.JSON
-
-- * Exported types
-type Container = M.Map String
+-- | Class of objects that can be converted to 'JSObject'
+-- lists-format.
+class DictObject a where
+ toDict :: a -> [(String, JSON.JSValue)]
-- | Serialised field data type.
data Field = Field { fieldName :: String
, fieldShow :: Maybe (Q Exp)
, fieldDefault :: Maybe (Q Exp)
, fieldConstr :: Maybe String
- , fieldIsContainer :: Bool
, fieldIsOptional :: Bool
}
, fieldShow = Nothing
, fieldDefault = Nothing
, fieldConstr = Nothing
- , fieldIsContainer = False
, fieldIsOptional = False
}
optionalField :: Field -> Field
optionalField field = field { fieldIsOptional = True }
--- | Marks a field as a container.
-containerField :: Field -> Field
-containerField field = field { fieldIsContainer = True }
-
-- | Sets custom functions on a field.
customField :: Name -- ^ The name of the read function
-> Name -- ^ The name of the show function
customField readfn showfn field =
field { fieldRead = Just (varE readfn), fieldShow = Just (varE showfn) }
+-- | Computes the record name for a given field, based on either the
+-- string value in the JSON serialisation or the custom named if any
+-- exists.
fieldRecordName :: Field -> String
fieldRecordName (Field { fieldName = name, fieldConstr = alias }) =
- maybe (camelCase name) id alias
+ fromMaybe (camelCase name) alias
-- | Computes the preferred variable name to use for the value of this
-- field. If the field has a specific constructor name, then we use a
_ -> map (\c -> if c == '-' then '_' else c) $ fieldName f
actualFieldType :: Field -> Q Type
-actualFieldType f | fieldIsContainer f = [t| Container $t |]
- | fieldIsOptional f = [t| Maybe $t |]
+actualFieldType f | fieldIsOptional f = [t| Maybe $t |]
| otherwise = t
where t = fieldType f
-> Q Exp -- ^ The value of the field as existing in the JSON message
-> Q Exp -- ^ The entire object in JSON object format
-> Q Exp -- ^ Resulting expression
-loadFn (Field { fieldIsContainer = True }) expr _ =
- [| $expr >>= readContainer |]
loadFn (Field { fieldRead = Just readfn }) expr o = [| $expr >>= $readfn $o |]
loadFn _ expr _ = expr
-- * Common field declarations
+-- | Timestamp fields description.
timeStampFields :: [Field]
timeStampFields =
[ defaultField [| 0::Double |] $ simpleField "ctime" [t| Double |]
, defaultField [| 0::Double |] $ simpleField "mtime" [t| Double |]
]
+-- | Serial number fields description.
serialFields :: [Field]
serialFields =
[ renameField "Serial" $ simpleField "serial_no" [t| Int |] ]
+-- | UUID fields description.
uuidFields :: [Field]
uuidFields = [ simpleField "uuid" [t| String |] ]
+-- | Tag set type alias.
+type TagSet = Set.Set String
+
-- | Tag field description.
tagsFields :: [Field]
tagsFields = [ defaultField [| Set.empty |] $
- simpleField "tags" [t| Set.Set String |] ]
+ simpleField "tags" [t| TagSet |] ]
-- * Helper functions
fromRawName :: String -> Name
fromRawName = mkName . (++ "FromRaw") . ensureLower
--- | Converts a name to it's varE/litE representations.
---
+-- | Converts a name to it's varE\/litE representations.
reprE :: Either String Name -> Q Exp
reprE = either stringE varE
appFn f x | f == VarE 'id = x
| otherwise = AppE f x
--- | Container loader
-readContainer :: (Monad m, JSON.JSON a) =>
- JSON.JSObject JSON.JSValue -> m (Container a)
-readContainer obj = do
- let kjvlist = JSON.fromJSObject obj
- kalist <- mapM (\(k, v) -> fromKeyValue k v >>= \a -> return (k, a)) kjvlist
- return $ M.fromList kalist
-
--- | Container dumper
-showContainer :: (JSON.JSON a) => Container a -> JSON.JSValue
-showContainer = JSON.makeObj . map (second JSON.showJSON) . M.toList
-
-- * Template code for simple raw type-equivalent ADTs
-- | Generates a data type declaration.
--
-- * /name/FromRaw, which (monadically) converts from a raw type to the type
--
--- Note that this is basically just a custom show/read instance,
+-- Note that this is basically just a custom show\/read instance,
-- nothing else.
declareADT :: Name -> String -> [(String, Name)] -> Q [Dec]
declareADT traw sname cons = do
constructorName (RecC name _) = return name
constructorName x = fail $ "Unhandled constructor " ++ show x
+-- | Extract all constructor names from a given type.
+reifyConsNames :: Name -> Q [String]
+reifyConsNames name = do
+ reify_result <- reify name
+ case reify_result of
+ TyConI (DataD _ _ _ cons _) -> mapM (liftM nameBase . constructorName) cons
+ o -> fail $ "Unhandled name passed to reifyConsNames, expected\
+ \ type constructor but got '" ++ show o ++ "'"
+
-- | Builds the generic constructor-to-string function.
--
-- This generates a simple function of the following form:
-- fname (ConStructorTwo {}) = trans_fun("ConStructorTwo")
-- @
--
--- This builds a custom list of name/string pairs and then uses
--- 'genToRaw' to actually generate the function
+-- This builds a custom list of name\/string pairs and then uses
+-- 'genToRaw' to actually generate the function.
genConstrToStr :: (String -> String) -> Name -> String -> Q [Dec]
genConstrToStr trans_fun name fname = do
- TyConI (DataD _ _ _ cons _) <- reify name
- cnames <- mapM (liftM nameBase . constructorName) cons
+ cnames <- reifyConsNames name
let svalues = map (Left . trans_fun) cnames
genToRaw ''String (mkName fname) name $ zip cnames svalues
genOpID :: Name -> String -> Q [Dec]
genOpID = genConstrToStr deCamelCase
+-- | Builds a list with all defined constructor names for a type.
+--
+-- @
+-- vstr :: String
+-- vstr = [...]
+-- @
+--
+-- Where the actual values of the string are the constructor names
+-- mapped via @trans_fun@.
+genAllConstr :: (String -> String) -> Name -> String -> Q [Dec]
+genAllConstr trans_fun name vstr = do
+ cnames <- reifyConsNames name
+ let svalues = sort $ map trans_fun cnames
+ vname = mkName vstr
+ sig = SigD vname (AppT ListT (ConT ''String))
+ body = NormalB (ListE (map (LitE . StringL) svalues))
+ return $ [sig, ValD (VarP vname) body []]
+
+-- | Generates a list of all defined opcode IDs.
+genAllOpIDs :: Name -> String -> Q [Dec]
+genAllOpIDs = genAllConstr deCamelCase
+
-- | OpCode parameter (field) type.
type OpParam = (String, Q Type, Q Exp)
sigt <- [t| $(conT (mkName "OpCode")) -> JSON.JSValue |]
return $ (SigD fname sigt, FunD fname cclauses)
+-- | Generates load code for a single constructor of the opcode data type.
loadConstructor :: String -> [Field] -> Q Exp
loadConstructor sname fields = do
let name = mkName sname
fstmts' = fstmts ++ [NoBindS (AppE (VarE 'return) cval)]
return $ DoE fstmts'
+-- | Generates the loadOpCode function.
genLoadOpCode :: [(String, [Field])] -> Q (Dec, Dec)
genLoadOpCode opdefs = do
let fname = mkName "loadOpCode"
genStrOfKey = genConstrToStr ensureLower
-- | LuxiOp parameter type.
-type LuxiParam = (String, Q Type, Q Exp)
+type LuxiParam = (String, Q Type)
-- | Generates the LuxiOp data type.
--
-- We can't use anything less generic, because the way different
-- operations are serialized differs on both parameter- and top-level.
--
--- There are three things to be defined for each parameter:
+-- There are two things to be defined for each parameter:
--
-- * name
--
-- * type
--
--- * operation; this is the operation performed on the parameter before
--- serialization
---
genLuxiOp :: String -> [(String, [LuxiParam])] -> Q [Dec]
genLuxiOp name cons = do
decl_d <- mapM (\(cname, fields) -> do
- fields' <- mapM (\(_, qt, _) ->
+ fields' <- mapM (\(_, qt) ->
qt >>= \t -> return (NotStrict, t))
fields
return $ NormalC (mkName cname) fields')
-- | Generates the \"save\" expression for a single luxi parameter.
saveLuxiField :: Name -> LuxiParam -> Q Exp
-saveLuxiField fvar (_, qt, fn) =
- [| JSON.showJSON ( $(liftM2 appFn fn $ varE fvar) ) |]
+saveLuxiField fvar (_, qt) =
+ [| JSON.showJSON $(varE fvar) |]
-- | Generates the \"save\" clause for entire LuxiOp constructor.
saveLuxiConstructor :: (String, [LuxiParam]) -> Q Clause
saveLuxiConstructor (sname, fields) = do
let cname = mkName sname
- fnames = map (\(nm, _, _) -> mkName nm) fields
+ fnames = map (mkName . fst) fields
pat = conP cname (map varP fnames)
flist = map (uncurry saveLuxiField) (zip fnames fields)
finval = if null flist
ser_decls <- buildObjectSerialisation sname fields
return $ declD:ser_decls
+-- | Generates an object definition: data type and its JSON instance.
buildObjectSerialisation :: String -> [Field] -> Q [Dec]
buildObjectSerialisation sname fields = do
let name = mkName sname
[rdjson, shjson]
return $ savedecls ++ [loadsig, loadfn, instdecl]
+-- | The toDict function name for a given type.
+toDictName :: String -> Name
+toDictName sname = mkName ("toDict" ++ sname)
+
+-- | Generates the save object functionality.
genSaveObject :: (Name -> Field -> Q Exp)
-> String -> [Field] -> Q [Dec]
genSaveObject save_fn sname fields = do
let name = mkName sname
fnames <- mapM (newName . fieldVariable) fields
let pat = conP name (map varP fnames)
- let tdname = mkName ("toDict" ++ sname)
+ let tdname = toDictName sname
tdsigt <- [t| $(conT name) -> [(String, JSON.JSValue)] |]
let felems = map (uncurry save_fn) (zip fnames fields)
return [SigD tdname tdsigt, FunD tdname [tclause],
SigD fname sigt, ValD (VarP fname) (NormalB cclause) []]
+-- | Generates the code for saving an object's field, handling the
+-- various types of fields that we have.
saveObjectField :: Name -> Field -> Q Exp
saveObjectField fvar field
- | isContainer = [| [( $nameE , JSON.showJSON . showContainer $ $fvarE)] |]
| fisOptional = [| case $(varE fvar) of
Nothing -> []
Just v -> [( $nameE, JSON.showJSON v)]
Just fn -> [| let (actual, extra) = $fn $fvarE
in extra ++ [( $nameE, JSON.showJSON actual)]
|]
- where isContainer = fieldIsContainer field
- fisOptional = fieldIsOptional field
+ where fisOptional = fieldIsOptional field
nameE = stringE (fieldName field)
fvarE = varE fvar
+-- | Generates the showJSON clause for a given object name.
objectShowJSON :: String -> Q Dec
objectShowJSON name = do
body <- [| JSON.showJSON . $(varE . mkName $ "save" ++ name) |]
return $ FunD (mkName "showJSON") [Clause [] (NormalB body) []]
+-- | Generates the load object functionality.
genLoadObject :: (Field -> Q (Name, Stmt))
-> String -> [Field] -> Q (Dec, Dec)
genLoadObject load_fn sname fields = do
return $ (SigD funname sigt,
FunD funname [Clause [VarP arg1] (NormalB (DoE fstmts')) []])
+-- | Generates code for loading an object's field.
loadObjectField :: Field -> Q (Name, Stmt)
loadObjectField field = do
let name = fieldVariable field
return (fvar, BindS (VarP fvar) bexp)
+-- | Builds the readJSON instance for a given object name.
objectReadJSON :: String -> Q Dec
objectReadJSON name = do
let s = mkName "s"
ser_decls_f <- buildObjectSerialisation sname_f fields
ser_decls_p <- buildPParamSerialisation sname_p fields
fill_decls <- fillParam sname field_pfx fields
- return $ [declF, declP] ++ ser_decls_f ++ ser_decls_p ++ fill_decls
-
+ return $ [declF, declP] ++ ser_decls_f ++ ser_decls_p ++ fill_decls ++
+ buildParamAllFields sname fields ++
+ buildDictObjectInst name_f sname_f
+
+-- | Builds a list of all fields of a parameter.
+buildParamAllFields :: String -> [Field] -> [Dec]
+buildParamAllFields sname fields =
+ let vname = mkName ("all" ++ sname ++ "ParamFields")
+ sig = SigD vname (AppT ListT (ConT ''String))
+ val = ListE $ map (LitE . StringL . fieldName) fields
+ in [sig, ValD (VarP vname) (NormalB val) []]
+
+-- | Builds the 'DictObject' instance for a filled parameter.
+buildDictObjectInst :: Name -> String -> [Dec]
+buildDictObjectInst name sname =
+ [InstanceD [] (AppT (ConT ''DictObject) (ConT name))
+ [ValD (VarP 'toDict) (NormalB (VarE (toDictName sname))) []]]
+
+-- | Generates the serialisation for a partial parameter.
buildPParamSerialisation :: String -> [Field] -> Q [Dec]
buildPParamSerialisation sname fields = do
let name = mkName sname
[rdjson, shjson]
return $ savedecls ++ [loadsig, loadfn, instdecl]
+-- | Generates code to save an optional parameter field.
savePParamField :: Name -> Field -> Q Exp
savePParamField fvar field = do
checkNonOptDef field
, Match (ConP 'Just [VarP actualVal])
(NormalB normalexpr) []
]
+
+-- | Generates code to load an optional parameter field.
loadPParamField :: Field -> Q (Name, Stmt)
loadPParamField field = do
checkNonOptDef field
$(varNameE $ "f_" ++ fname)
$(varNameE $ "p_" ++ fname) |]) []
+-- | Builds a function that executes the filling of partial parameter
+-- from a full copy (similar to Python's fillDict).
fillParam :: String -> String -> [Field] -> Q [Dec]
fillParam sname field_pfx fields = do
let fnames = map (\fd -> field_pfx ++ fieldRecordName fd) fields
projects / ganeti-local / blobdiff