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nixpkgs/lib/types.nix

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# Definitions related to run-time type checking. Used in particular
# to type-check NixOS configurations.
with import ./lists.nix;
with import ./attrsets.nix;
with import ./options.nix;
with import ./trivial.nix;
with import ./strings.nix;
with {inherit (import ./modules.nix) mergeDefinitions filterOverrides; };
rec {
isType = type: x: (x._type or "") == type;
setType = typeName: value: value // {
_type = typeName;
};
# Default type merging function
# takes two type functors and return the merged type
defaultTypeMerge = f: f':
let wrapped = f.wrapped.typeMerge f'.wrapped.functor;
payload = f.binOp f.payload f'.payload;
in
# cannot merge different types
if f.name != f'.name
then null
# simple types
else if (f.wrapped == null && f'.wrapped == null)
&& (f.payload == null && f'.payload == null)
then f.type
# composed types
else if (f.wrapped != null && f'.wrapped != null) && (wrapped != null)
then f.type wrapped
# value types
else if (f.payload != null && f'.payload != null) && (payload != null)
then f.type payload
else null;
# Default type functor
defaultFunctor = name: {
inherit name;
type = types."${name}" or null;
wrapped = null;
payload = null;
binOp = a: b: null;
};
isOptionType = isType "option-type";
mkOptionType =
{ # Human-readable representation of the type, should be equivalent to
# the type function name.
name
, # Description of the type, defined recursively by embedding the the wrapped type if any.
description ? null
, # Function applied to each definition that should return true if
# its type-correct, false otherwise.
check ? (x: true)
, # Merge a list of definitions together into a single value.
# This function is called with two arguments: the location of
# the option in the configuration as a list of strings
# (e.g. ["boot" "loader "grub" "enable"]), and a list of
# definition values and locations (e.g. [ { file = "/foo.nix";
# value = 1; } { file = "/bar.nix"; value = 2 } ]).
merge ? mergeDefaultOption
, # Return a flat list of sub-options. Used to generate
# documentation.
getSubOptions ? prefix: {}
, # List of modules if any, or null if none.
getSubModules ? null
, # Function for building the same option type with a different list of
# modules.
substSubModules ? m: null
, # Function that merge type declarations.
# internal, takes a functor as argument and returns the merged type.
# returning null means the type is not mergeable
typeMerge ? defaultTypeMerge functor
, # The type functor.
# internal, representation of the type as an attribute set.
# name: name of the type
# type: type function.
# wrapped: the type wrapped in case of compound types.
# payload: values of the type, two payloads of the same type must be
# combinable with the binOp binary operation.
# binOp: binary operation that merge two payloads of the same type.
functor ? defaultFunctor name
}:
{ _type = "option-type";
inherit name check merge getSubOptions getSubModules substSubModules typeMerge functor;
description = if description == null then name else description;
};
types = rec {
unspecified = mkOptionType {
name = "unspecified";
};
bool = mkOptionType {
name = "bool";
description = "boolean";
check = isBool;
merge = mergeEqualOption;
};
int = mkOptionType rec {
name = "int";
description = "integer";
check = isInt;
merge = mergeOneOption;
};
str = mkOptionType {
name = "str";
description = "string";
check = isString;
merge = mergeOneOption;
};
# Merge multiple definitions by concatenating them (with the given
# separator between the values).
separatedString = sep: mkOptionType rec {
name = "separatedString";
description = "string";
check = isString;
merge = loc: defs: concatStringsSep sep (getValues defs);
functor = (defaultFunctor name) // {
payload = sep;
binOp = sepLhs: sepRhs:
if sepLhs == sepRhs then sepLhs
else null;
};
};
lines = separatedString "\n";
commas = separatedString ",";
envVar = separatedString ":";
# Deprecated; should not be used because it quietly concatenates
# strings, which is usually not what you want.
string = separatedString "";
attrs = mkOptionType {
name = "attrs";
description = "attribute set";
check = isAttrs;
merge = loc: foldl' (res: def: mergeAttrs res def.value) {};
};
# derivation is a reserved keyword.
package = mkOptionType {
lib/types: Set name of types.package to "package" Nobody seems to have noticed this (except @Profpatsch) that options with a "package" type do not get included in the manual. So debugging this was a bit more involving because while generating the manual there is an optionList' attribute built from the collected attributes of all the option declarations. Up to that point everything is fine except if it comes to builtins.toXML, where attributes with { type = "derivation" } won't get included, for example see here: nix-repl> builtins.toXML { type = "derivation"; foo = "bar"; } "<?xml version='1.0' encoding='utf-8'?>\n<expr>\n <derivation> <repeated />\n </derivation>\n</expr>\n" nix-repl> builtins.toXML { type = "somethingelse"; foo = "bar"; } "<?xml version='1.0' encoding='utf-8'?>\n<expr>\n <attrs> <attr name=\"foo\">\n <string value=\"bar\" />\n </attr> <attr name=\"type\">\n <string value=\"somethingelse\" /> </attr>\n </attrs>\n</expr>\n" The following function in libexpr/eval.cc (Nix) is responsible for toXML dropping the attributes: bool EvalState::isDerivation(Value & v) { if (v.type != tAttrs) return false; Bindings::iterator i = v.attrs->find(sType); if (i == v.attrs->end()) return false; forceValue(*i->value); if (i->value->type != tString) return false; return strcmp(i->value->string.s, "derivation") == 0; } So I've renamed this now to "package" which is not only more consistent with the option type but also shouldn't cause similar issues anymore. Tested this on base of b60ceea, because building the dependencies on recent libc/staging changes on master took too long. Signed-off-by: aszlig <aszlig@redmoonstudios.org> Reported-by: Profpatsch <mail@profpatsch.de>
7 years ago
name = "package";
check = x: isDerivation x || isStorePath x;
merge = loc: defs:
let res = mergeOneOption loc defs;
in if isDerivation res then res else toDerivation res;
};
shellPackage = package // {
check = x: (package.check x) && (hasAttr "shellPath" x);
};
path = mkOptionType {
name = "path";
# Hacky: there is no ‘isPath’ primop.
check = x: builtins.substring 0 1 (toString x) == "/";
merge = mergeOneOption;
};
# drop this in the future:
list = builtins.trace "`types.list' is deprecated; use `types.listOf' instead" types.listOf;
listOf = elemType: mkOptionType rec {
name = "listOf";
description = "list of ${elemType.description}s";
check = isList;
merge = loc: defs:
map (x: x.value) (filter (x: x ? value) (concatLists (imap (n: def:
if isList def.value then
imap (m: def':
(mergeDefinitions
(loc ++ ["[definition ${toString n}-entry ${toString m}]"])
elemType
[{ inherit (def) file; value = def'; }]
).optionalValue
) def.value
else
throw "The option value `${showOption loc}' in `${def.file}' is not a list.") defs)));
getSubOptions = prefix: elemType.getSubOptions (prefix ++ ["*"]);
getSubModules = elemType.getSubModules;
substSubModules = m: listOf (elemType.substSubModules m);
functor = (defaultFunctor name) // { wrapped = elemType; };
};
attrsOf = elemType: mkOptionType rec {
name = "attrsOf";
description = "attribute set of ${elemType.description}s";
check = isAttrs;
merge = loc: defs:
mapAttrs (n: v: v.value) (filterAttrs (n: v: v ? value) (zipAttrsWith (name: defs:
(mergeDefinitions (loc ++ [name]) elemType defs).optionalValue
)
# Push down position info.
(map (def: listToAttrs (mapAttrsToList (n: def':
{ name = n; value = { inherit (def) file; value = def'; }; }) def.value)) defs)));
getSubOptions = prefix: elemType.getSubOptions (prefix ++ ["<name>"]);
getSubModules = elemType.getSubModules;
substSubModules = m: attrsOf (elemType.substSubModules m);
functor = (defaultFunctor name) // { wrapped = elemType; };
};
# List or attribute set of ...
loaOf = elemType:
let
convertIfList = defIdx: def:
if isList def.value then
{ inherit (def) file;
value = listToAttrs (
imap (elemIdx: elem:
{ name = elem.name or "unnamed-${toString defIdx}.${toString elemIdx}";
value = elem;
}) def.value);
}
else
def;
listOnly = listOf elemType;
attrOnly = attrsOf elemType;
in mkOptionType rec {
name = "loaOf";
description = "list or attribute set of ${elemType.description}s";
check = x: isList x || isAttrs x;
merge = loc: defs: attrOnly.merge loc (imap convertIfList defs);
getSubOptions = prefix: elemType.getSubOptions (prefix ++ ["<name?>"]);
getSubModules = elemType.getSubModules;
substSubModules = m: loaOf (elemType.substSubModules m);
functor = (defaultFunctor name) // { wrapped = elemType; };
};
# List or element of ...
loeOf = elemType: mkOptionType rec {
name = "loeOf";
description = "element or list of ${elemType.description}s";
check = x: isList x || elemType.check x;
merge = loc: defs:
let
defs' = filterOverrides defs;
res = (head defs').value;
in
if isList res then concatLists (getValues defs')
else if lessThan 1 (length defs') then
throw "The option `${showOption loc}' is defined multiple times, in ${showFiles (getFiles defs)}."
else if !isString res then
throw "The option `${showOption loc}' does not have a string value, in ${showFiles (getFiles defs)}."
else res;
functor = (defaultFunctor name) // { wrapped = elemType; };
};
uniq = elemType: mkOptionType rec {
name = "uniq";
inherit (elemType) description check;
merge = mergeOneOption;
getSubOptions = elemType.getSubOptions;
getSubModules = elemType.getSubModules;
substSubModules = m: uniq (elemType.substSubModules m);
functor = (defaultFunctor name) // { wrapped = elemType; };
};
nullOr = elemType: mkOptionType rec {
name = "nullOr";
description = "null or ${elemType.description}";
check = x: x == null || elemType.check x;
merge = loc: defs:
let nrNulls = count (def: def.value == null) defs; in
if nrNulls == length defs then null
else if nrNulls != 0 then
throw "The option `${showOption loc}' is defined both null and not null, in ${showFiles (getFiles defs)}."
else elemType.merge loc defs;
getSubOptions = elemType.getSubOptions;
getSubModules = elemType.getSubModules;
substSubModules = m: nullOr (elemType.substSubModules m);
functor = (defaultFunctor name) // { wrapped = elemType; };
};
submodule = opts:
let
opts' = toList opts;
inherit (import ./modules.nix) evalModules;
in
mkOptionType rec {
name = "submodule";
check = x: isAttrs x || isFunction x;
merge = loc: defs:
let
coerce = def: if isFunction def then def else { config = def; };
modules = opts' ++ map (def: { _file = def.file; imports = [(coerce def.value)]; }) defs;
in (evalModules {
inherit modules;
args.name = last loc;
prefix = loc;
}).config;
getSubOptions = prefix: (evalModules
{ modules = opts'; inherit prefix;
# FIXME: hack to get shit to evaluate.
args = { name = ""; }; }).options;
getSubModules = opts';
substSubModules = m: submodule m;
functor = (defaultFunctor name) // {
# Merging of submodules is done as part of mergeOptionDecls, as we have to annotate
# each submodule with its location.
payload = [];
binOp = lhs: rhs: [];
};
};
enum = values:
let
show = v:
if builtins.isString v then ''"${v}"''
else if builtins.isInt v then builtins.toString v
else ''<${builtins.typeOf v}>'';
in
mkOptionType rec {
name = "enum";
description = "one of ${concatMapStringsSep ", " show values}";
check = flip elem values;
merge = mergeOneOption;
functor = (defaultFunctor name) // { payload = values; binOp = a: b: unique (a ++ b); };
};
either = t1: t2: mkOptionType rec {
name = "either";
description = "${t1.description} or ${t2.description}";
check = x: t1.check x || t2.check x;
merge = loc: defs:
let
defList = map (d: d.value) defs;
in
if all (x: t1.check x) defList
then t1.merge loc defs
else if all (x: t2.check x) defList
then t2.merge loc defs
else mergeOneOption loc defs;
typeMerge = f':
let mt1 = t1.typeMerge (elemAt f'.wrapped 0).functor;
mt2 = t2.typeMerge (elemAt f'.wrapped 1).functor;
in
if (name == f'.name) && (mt1 != null) && (mt2 != null)
then functor.type mt1 mt2
else null;
functor = (defaultFunctor name) // { wrapped = [ t1 t2 ]; };
};
coercedTo = coercedType: coerceFunc: finalType:
assert coercedType.getSubModules == null;
mkOptionType rec {
name = "coercedTo";
description = "${finalType.description} or ${coercedType.description}";
check = x: finalType.check x || coercedType.check x;
merge = loc: defs:
let
coerceVal = val:
if finalType.check val then val
else let
coerced = coerceFunc val;
in assert finalType.check coerced; coerced;
in finalType.merge loc (map (def: def // { value = coerceVal def.value; }) defs);
getSubOptions = finalType.getSubOptions;
getSubModules = finalType.getSubModules;
substSubModules = m: coercedTo coercedType coerceFunc (finalType.substSubModules m);
typeMerge = t1: t2: null;
functor = (defaultFunctor name) // { wrapped = finalType; };
};
# Obsolete alternative to configOf. It takes its option
# declarations from the ‘options’ attribute of containing option
# declaration.
optionSet = mkOptionType {
name = builtins.trace "types.optionSet is deprecated; use types.submodule instead" "optionSet";
description = "option set";
};
# Augment the given type with an additional type check function.
addCheck = elemType: check: elemType // { check = x: elemType.check x && check x; };
};
}