-{-# LANGUAGE TemplateHaskell, QuasiQuotes #-}
+{-# LANGUAGE TemplateHaskell #-}
{-| TemplateHaskell helper for HTools.
{-
-Copyright (C) 2011 Google Inc.
+Copyright (C) 2011, 2012 Google Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
, makeJSONInstance
, genOpID
, genOpCode
- , noDefault
, genStrOfOp
, genStrOfKey
, genLuxiOp
import qualified Text.JSON as JSON
+import Ganeti.HTools.JSON
+
-- * Exported types
type Container = M.Map String
containerField field = field { fieldIsContainer = True }
-- | Sets custom functions on a field.
-customField :: Q Exp -> Q Exp -> Field -> Field
+customField :: Name -- ^ The name of the read function
+ -> Name -- ^ The name of the show function
+ -> Field -- ^ The original field
+ -> Field -- ^ Updated field
customField readfn showfn field =
- field { fieldRead = Just readfn, fieldShow = Just showfn }
+ field { fieldRead = Just (varE readfn), fieldShow = Just (varE showfn) }
fieldRecordName :: Field -> String
fieldRecordName (Field { fieldName = name, fieldConstr = alias }) =
maybe (camelCase name) id 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
+-- first-letter-lowercased version of that; otherwise, we simply use
+-- the field name. See also 'fieldRecordName'.
fieldVariable :: Field -> String
-fieldVariable = map toLower . fieldRecordName
+fieldVariable f =
+ case (fieldConstr f) of
+ Just name -> ensureLower name
+ _ -> fieldName f
actualFieldType :: Field -> Q Type
actualFieldType f | fieldIsContainer f = [t| Container $t |]
fail $ "Default field " ++ name ++ " used in parameter declaration"
checkNonOptDef _ = return ()
-loadFn :: Field -> Q Exp -> Q Exp
-loadFn (Field { fieldIsContainer = True }) expr = [| $expr >>= readContainer |]
-loadFn (Field { fieldRead = Just readfn }) expr = [| $expr >>= $readfn |]
-loadFn _ expr = expr
-
-saveFn :: Field -> Q Exp -> Q Exp
-saveFn (Field { fieldIsContainer = True }) expr = [| showContainer $expr |]
-saveFn (Field { fieldRead = Just readfn }) expr = [| $readfn $expr |]
-saveFn _ expr = expr
+-- | Produces the expression that will de-serialise a given
+-- field. Since some custom parsing functions might need to use the
+-- entire object, we do take and pass the object to any custom read
+-- functions.
+loadFn :: Field -- ^ The field definition
+ -> 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
| otherwise = AppE f x
-- | Container loader
-readContainer :: (Monad m) => JSON.JSObject a -> m (Container a)
-readContainer = return . M.fromList . JSON.fromJSObject
+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
-- @
genToRaw :: Name -> Name -> Name -> [(String, Either String Name)] -> Q [Dec]
genToRaw traw fname tname constructors = do
- sigt <- [t| $(conT tname) -> $(conT traw) |]
+ let sigt = AppT (AppT ArrowT (ConT tname)) (ConT traw)
-- the body clauses, matching on the constructor and returning the
-- raw value
clauses <- mapM (\(c, v) -> clause [recP (mkName c) []]
-- @
--
-- in an instance JSON /name/ declaration
-genShowJSON :: String -> Q [Dec]
-genShowJSON name = [d| showJSON = JSON.showJSON . $(varE (toRawName name)) |]
+genShowJSON :: String -> Q Dec
+genShowJSON name = do
+ body <- [| JSON.showJSON . $(varE (toRawName name)) |]
+ return $ FunD (mkName "showJSON") [Clause [] (NormalB body) []]
-- | Creates the readJSON member of a JSON instance declaration.
--
JSON.Ok s' -> $(varE (fromRawName name)) s'
JSON.Error e ->
JSON.Error $ "Can't parse raw value for type " ++
- $(stringE name) ++ ": " ++ e
+ $(stringE name) ++ ": " ++ e ++ " from " ++
+ show $(varE s)
|]
return $ FunD (mkName "readJSON") [Clause [VarP s] (NormalB body) []]
let base = nameBase name
showJ <- genShowJSON base
readJ <- genReadJSON base
- return [InstanceD [] (AppT (ConT ''JSON.JSON) (ConT name)) (readJ:showJ)]
+ return [InstanceD [] (AppT (ConT ''JSON.JSON) (ConT name)) [readJ,showJ]]
-- * Template code for opcodes
-- datatype and the JSON serialisation out of it. We can't use a
-- generic serialisation since we need to be compatible with Ganeti's
-- own, so we have a few quirks to work around.
---
--- There are three things to be defined for each parameter:
---
--- * name
---
--- * type; if this is 'Maybe', will only be serialised if it's a
--- 'Just' value
---
--- * default; if missing, won't raise an exception, but will instead
--- use the default
---
genOpCode :: String -- ^ Type name to use
- -> [(String, [OpParam])] -- ^ Constructor name and parameters
+ -> [(String, [Field])] -- ^ Constructor name and parameters
-> Q [Dec]
genOpCode name cons = do
decl_d <- mapM (\(cname, fields) -> do
-- we only need the type of the field, without Q
- fields' <- mapM (\(_, qt, _) ->
- qt >>= \t -> return (NotStrict, t))
- fields
- return $ NormalC (mkName cname) fields')
+ fields' <- mapM actualFieldType fields
+ let fields'' = zip (repeat NotStrict) fields'
+ return $ NormalC (mkName cname) fields'')
cons
let declD = DataD [] (mkName name) [] decl_d [''Show, ''Read, ''Eq]
isOptional (AppT (ConT dt) _) | dt == ''Maybe = True
isOptional _ = False
--- | Generates the \"save\" expression for a single opcode parameter.
---
--- There is only one special handling mode: if the parameter is of
--- 'Maybe' type, then we only save it if it's a 'Just' value,
--- otherwise we skip it.
-saveField :: Name -- ^ The name of variable that contains the value
- -> OpParam -- ^ Parameter definition
- -> Q Exp
-saveField fvar (fname, qt, _) = do
- t <- qt
- let fnexp = stringE fname
- fvare = varE fvar
- (if isOptional t
- then [| case $fvare of
- Just v' -> [( $fnexp, $showJSONE v')]
- Nothing -> []
- |]
- else [| [( $fnexp, $showJSONE $fvare )] |])
-
-- | Generates the \"save\" clause for an entire opcode constructor.
--
-- This matches the opcode with variables named the same as the
-- constructor fields (just so that the spliced in code looks nicer),
--- and passes those name plus the parameter definition to 'saveField'.
+-- and passes those name plus the parameter definition to 'saveObjectField'.
saveConstructor :: String -- ^ The constructor name
- -> [OpParam] -- ^ The parameter definitions for this
+ -> [Field] -- ^ The parameter definitions for this
-- constructor
-> Q Clause -- ^ Resulting clause
saveConstructor sname fields = do
let cname = mkName sname
- let fnames = map (\(n, _, _) -> mkName n) fields
+ let fnames = map (mkName . fieldVariable) fields
let pat = conP cname (map varP fnames)
- let felems = map (uncurry saveField) (zip fnames fields)
+ let felems = map (uncurry saveObjectField) (zip fnames fields)
-- now build the OP_ID serialisation
opid = [| [( $(stringE "OP_ID"),
- $showJSONE $(stringE . deCamelCase $ sname) )] |]
+ JSON.showJSON $(stringE . deCamelCase $ sname) )] |]
flist = listE (opid:felems)
-- and finally convert all this to a json object
flist' = [| $(varNameE "makeObj") (concat $flist) |]
--
-- This builds a per-constructor match clause that contains the
-- respective constructor-serialisation code.
-genSaveOpCode :: [(String, [OpParam])] -> Q (Dec, Dec)
+genSaveOpCode :: [(String, [Field])] -> Q (Dec, Dec)
genSaveOpCode opdefs = do
cclauses <- mapM (uncurry saveConstructor) opdefs
let fname = mkName "saveOpCode"
sigt <- [t| $(conT (mkName "OpCode")) -> JSON.JSValue |]
return $ (SigD fname sigt, FunD fname cclauses)
--- | Generates the \"load\" field for a single parameter.
---
--- There is custom handling, depending on how the parameter is
--- specified. For a 'Maybe' type parameter, we allow that it is not
--- present (via 'Utils.maybeFromObj'). Otherwise, if there is a
--- default value, we allow the parameter to be abset, and finally if
--- there is no default value, we require its presence.
-loadField :: OpParam -> Q (Name, Stmt)
-loadField (fname, qt, qdefa) = do
- let fvar = mkName fname
- t <- qt
- defa <- qdefa
- -- these are used in all patterns below
- let objvar = varNameE "o"
- objfield = stringE fname
- bexp <- if isOptional t
- then [| $((varNameE "maybeFromObj")) $objvar $objfield |]
- else case defa of
- AppE (ConE dt) defval | dt == 'Just ->
- -- but has a default value
- [| $(varNameE "fromObjWithDefault")
- $objvar $objfield $(return defval) |]
- ConE dt | dt == 'Nothing ->
- [| $(varNameE "fromObj") $objvar $objfield |]
- s -> fail $ "Invalid default value " ++ show s ++
- ", expecting either 'Nothing' or a 'Just defval'"
- return (fvar, BindS (VarP fvar) bexp)
-
-loadConstructor :: String -> [OpParam] -> Q Exp
+loadConstructor :: String -> [Field] -> Q Exp
loadConstructor sname fields = do
let name = mkName sname
- fbinds <- mapM loadField fields
+ fbinds <- mapM loadObjectField fields
let (fnames, fstmts) = unzip fbinds
let cval = foldl (\accu fn -> AppE accu (VarE fn)) (ConE name) fnames
fstmts' = fstmts ++ [NoBindS (AppE (VarE 'return) cval)]
return $ DoE fstmts'
-genLoadOpCode :: [(String, [OpParam])] -> Q (Dec, Dec)
+genLoadOpCode :: [(String, [Field])] -> Q (Dec, Dec)
genLoadOpCode opdefs = do
let fname = mkName "loadOpCode"
arg1 = mkName "v"
sigt <- [t| JSON.JSValue -> JSON.Result $(conT (mkName "OpCode")) |]
return $ (SigD fname sigt, FunD fname [Clause [VarP arg1] (NormalB body) []])
--- | No default type.
-noDefault :: Q Exp
-noDefault = conE 'Nothing
-
-- * Template code for luxi
-- | Constructor-to-string for LuxiOp.
fields
return $ NormalC (mkName cname) fields')
cons
- let declD = DataD [] (mkName name) [] decl_d [''Show, ''Read]
+ let declD = DataD [] (mkName name) [] decl_d [''Show, ''Read, ''Eq]
(savesig, savefn) <- genSaveLuxiOp cons
- return [declD, savesig, savefn]
+ req_defs <- declareSADT "LuxiReq" .
+ map (\(str, _) -> ("Req" ++ str, mkName ("luxiReq" ++ str))) $
+ cons
+ return $ [declD, savesig, savefn] ++ req_defs
-- | Generates the \"save\" expression for a single luxi parameter.
saveLuxiField :: Name -> LuxiParam -> Q Exp
let name = mkName sname
fields_d <- mapM (fieldTypeInfo field_pfx) fields
let decl_d = RecC name fields_d
- let declD = DataD [] name [] [decl_d] [''Show, ''Read]
+ let declD = DataD [] name [] [decl_d] [''Show, ''Read, ''Eq]
ser_decls <- buildObjectSerialisation sname fields
return $ declD:ser_decls
shjson <- objectShowJSON sname
rdjson <- objectReadJSON sname
let instdecl = InstanceD [] (AppT (ConT ''JSON.JSON) (ConT name))
- (rdjson:shjson)
+ [rdjson, shjson]
return $ savedecls ++ [loadsig, loadfn, instdecl]
genSaveObject :: (Name -> Field -> Q Exp)
saveObjectField :: Name -> Field -> Q Exp
saveObjectField fvar field
- | isContainer = [| [( $nameE , $showJSONE . showContainer $ $fvarE)] |]
+ | isContainer = [| [( $nameE , JSON.showJSON . showContainer $ $fvarE)] |]
| fisOptional = [| case $(varE fvar) of
Nothing -> []
- Just v -> [( $nameE, $showJSONE v)]
+ Just v -> [( $nameE, JSON.showJSON v)]
|]
| otherwise = case fieldShow field of
- Nothing -> [| [( $nameE, $showJSONE $fvarE)] |]
- Just fn -> [| [( $nameE, $showJSONE . $fn $ $fvarE)] |]
+ Nothing -> [| [( $nameE, JSON.showJSON $fvarE)] |]
+ Just fn -> [| let (actual, extra) = $fn $fvarE
+ in extra ++ [( $nameE, JSON.showJSON actual)]
+ |]
where isContainer = fieldIsContainer field
fisOptional = fieldIsOptional field
nameE = stringE (fieldName field)
fvarE = varE fvar
-objectShowJSON :: String -> Q [Dec]
-objectShowJSON name =
- [d| showJSON = JSON.showJSON . $(varE . mkName $ "save" ++ name) |]
+objectShowJSON :: String -> Q Dec
+objectShowJSON name = do
+ body <- [| JSON.showJSON . $(varE . mkName $ "save" ++ name) |]
+ return $ FunD (mkName "showJSON") [Clause [] (NormalB body) []]
genLoadObject :: (Field -> Q (Name, Stmt))
-> String -> [Field] -> Q (Dec, Dec)
[| $(varNameE "fromObjWithDefault") $objvar
$objfield $defv |]
Nothing -> [| $(varNameE "fromObj") $objvar $objfield |]
- bexp <- loadFn field loadexp
+ bexp <- loadFn field loadexp objvar
return (fvar, BindS (VarP fvar) bexp)
fields_p <- mapM (paramFieldTypeInfo field_pfx) fields
let decl_f = RecC name_f fields_f
decl_p = RecC name_p fields_p
- let declF = DataD [] name_f [] [decl_f] [''Show, ''Read]
- declP = DataD [] name_p [] [decl_p] [''Show, ''Read]
+ let declF = DataD [] name_f [] [decl_f] [''Show, ''Read, ''Eq]
+ declP = DataD [] name_p [] [decl_p] [''Show, ''Read, ''Eq]
ser_decls_f <- buildObjectSerialisation sname_f fields
ser_decls_p <- buildPParamSerialisation sname_p fields
fill_decls <- fillParam sname field_pfx fields
shjson <- objectShowJSON sname
rdjson <- objectReadJSON sname
let instdecl = InstanceD [] (AppT (ConT ''JSON.JSON) (ConT name))
- (rdjson:shjson)
+ [rdjson, shjson]
return $ savedecls ++ [loadsig, loadfn, instdecl]
savePParamField :: Name -> Field -> Q Exp
let objvar = varNameE "o"
objfield = stringE name
loadexp = [| $(varNameE "maybeFromObj") $objvar $objfield |]
- bexp <- loadFn field loadexp
+ bexp <- loadFn field loadexp objvar
return (fvar, BindS (VarP fvar) bexp)
-- | Builds a simple declaration of type @n_x = fromMaybe f_x p_x@.
projects / ganeti-local / blobdiff