1
0
Fork 1
mirror of https://github.com/NixOS/nixpkgs.git synced 2024-12-05 12:02:47 +00:00
nixpkgs/lib/types.nix
Silvan Mosberger fb1969806f
Merge pull request #117888 from kvtb/patch-3
types.nix: fix outdated comment
2021-05-08 05:46:10 +02:00

664 lines
24 KiB
Nix
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

# Definitions related to run-time type checking. Used in particular
# to type-check NixOS configurations.
{ lib }:
let
inherit (lib)
elem
flip
functionArgs
isAttrs
isBool
isDerivation
isFloat
isFunction
isInt
isList
isString
isStorePath
setFunctionArgs
toDerivation
toList
;
inherit (lib.lists)
all
concatLists
count
elemAt
filter
foldl'
head
imap1
last
length
tail
unique
;
inherit (lib.attrsets)
attrNames
filterAttrs
hasAttr
mapAttrs
optionalAttrs
zipAttrsWith
;
inherit (lib.options)
getFiles
getValues
mergeDefaultOption
mergeEqualOption
mergeOneOption
showFiles
showOption
;
inherit (lib.strings)
concatMapStringsSep
concatStringsSep
escapeNixString
isCoercibleToString
;
inherit (lib.trivial)
boolToString
;
inherit (lib.modules) mergeDefinitions;
outer_types =
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 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
, # Whether this type has a value representing nothingness. If it does,
# this should be a value of the form { value = <the nothing value>; }
# If it doesn't, this should be {}
# This may be used when a value is required for `mkIf false`. This allows the extra laziness in e.g. `lazyAttrsOf`.
emptyValue ? {}
, # 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
, # The deprecation message to display when this type is used by an option
# If null, the type isn't deprecated
deprecationMessage ? null
, # The types that occur in the definition of this type. This is used to
# issue deprecation warnings recursively. Can also be used to reuse
# nested types
nestedTypes ? {}
}:
{ _type = "option-type";
inherit name check merge emptyValue getSubOptions getSubModules substSubModules typeMerge functor deprecationMessage nestedTypes;
description = if description == null then name else description;
};
# When adding new types don't forget to document them in
# nixos/doc/manual/development/option-types.xml!
types = rec {
anything = mkOptionType {
name = "anything";
description = "anything";
check = value: true;
merge = loc: defs:
let
getType = value:
if isAttrs value && isCoercibleToString value
then "stringCoercibleSet"
else builtins.typeOf value;
# Returns the common type of all definitions, throws an error if they
# don't have the same type
commonType = foldl' (type: def:
if getType def.value == type
then type
else throw "The option `${showOption loc}' has conflicting option types in ${showFiles (getFiles defs)}"
) (getType (head defs).value) defs;
mergeFunction = {
# Recursively merge attribute sets
set = (attrsOf anything).merge;
# Safe and deterministic behavior for lists is to only accept one definition
# listOf only used to apply mkIf and co.
list =
if length defs > 1
then throw "The option `${showOption loc}' has conflicting definitions, in ${showFiles (getFiles defs)}."
else (listOf anything).merge;
# This is the type of packages, only accept a single definition
stringCoercibleSet = mergeOneOption;
# Otherwise fall back to only allowing all equal definitions
}.${commonType} or mergeEqualOption;
in mergeFunction loc defs;
};
unspecified = mkOptionType {
name = "unspecified";
};
bool = mkOptionType {
name = "bool";
description = "boolean";
check = isBool;
merge = mergeEqualOption;
};
int = mkOptionType {
name = "int";
description = "signed integer";
check = isInt;
merge = mergeEqualOption;
};
# Specialized subdomains of int
ints =
let
betweenDesc = lowest: highest:
"${toString lowest} and ${toString highest} (both inclusive)";
between = lowest: highest:
assert lib.assertMsg (lowest <= highest)
"ints.between: lowest must be smaller than highest";
addCheck int (x: x >= lowest && x <= highest) // {
name = "intBetween";
description = "integer between ${betweenDesc lowest highest}";
};
ign = lowest: highest: name: docStart:
between lowest highest // {
inherit name;
description = docStart + "; between ${betweenDesc lowest highest}";
};
unsign = bit: range: ign 0 (range - 1)
"unsignedInt${toString bit}" "${toString bit} bit unsigned integer";
sign = bit: range: ign (0 - (range / 2)) (range / 2 - 1)
"signedInt${toString bit}" "${toString bit} bit signed integer";
in {
/* An int with a fixed range.
*
* Example:
* (ints.between 0 100).check (-1)
* => false
* (ints.between 0 100).check (101)
* => false
* (ints.between 0 0).check 0
* => true
*/
inherit between;
unsigned = addCheck types.int (x: x >= 0) // {
name = "unsignedInt";
description = "unsigned integer, meaning >=0";
};
positive = addCheck types.int (x: x > 0) // {
name = "positiveInt";
description = "positive integer, meaning >0";
};
u8 = unsign 8 256;
u16 = unsign 16 65536;
# the biggest int Nix accepts is 2^63 - 1 (9223372036854775808)
# the smallest int Nix accepts is -2^63 (-9223372036854775807)
u32 = unsign 32 4294967296;
# u64 = unsign 64 18446744073709551616;
s8 = sign 8 256;
s16 = sign 16 65536;
s32 = sign 32 4294967296;
};
# Alias of u16 for a port number
port = ints.u16;
float = mkOptionType {
name = "float";
description = "floating point number";
check = isFloat;
merge = mergeEqualOption;
};
str = mkOptionType {
name = "str";
description = "string";
check = isString;
merge = mergeEqualOption;
};
strMatching = pattern: mkOptionType {
name = "strMatching ${escapeNixString pattern}";
description = "string matching the pattern ${pattern}";
check = x: str.check x && builtins.match pattern x != null;
inherit (str) merge;
};
# Merge multiple definitions by concatenating them (with the given
# separator between the values).
separatedString = sep: mkOptionType rec {
name = "separatedString";
description = if sep == ""
then "Concatenated string" # for types.string.
else "strings concatenated with ${builtins.toJSON sep}"
;
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 "" // {
name = "string";
deprecationMessage = "See https://github.com/NixOS/nixpkgs/pull/66346 for better alternative types.";
};
attrs = mkOptionType {
name = "attrs";
description = "attribute set";
check = isAttrs;
merge = loc: foldl' (res: def: res // def.value) {};
emptyValue = { value = {}; };
};
# derivation is a reserved keyword.
package = mkOptionType {
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: isDerivation x && hasAttr "shellPath" x;
};
path = mkOptionType {
name = "path";
check = x: isCoercibleToString x && builtins.substring 0 1 (toString x) == "/";
merge = mergeEqualOption;
};
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 (imap1 (n: def:
imap1 (m: def':
(mergeDefinitions
(loc ++ ["[definition ${toString n}-entry ${toString m}]"])
elemType
[{ inherit (def) file; value = def'; }]
).optionalValue
) def.value
) defs)));
emptyValue = { value = {}; };
getSubOptions = prefix: elemType.getSubOptions (prefix ++ ["*"]);
getSubModules = elemType.getSubModules;
substSubModules = m: listOf (elemType.substSubModules m);
functor = (defaultFunctor name) // { wrapped = elemType; };
nestedTypes.elemType = elemType;
};
nonEmptyListOf = elemType:
let list = addCheck (types.listOf elemType) (l: l != []);
in list // {
description = "non-empty " + list.description;
# Note: emptyValue is left as is, because another module may define an element.
};
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: mapAttrs (n: v: { inherit (def) file; value = v; }) def.value) defs)));
emptyValue = { value = {}; };
getSubOptions = prefix: elemType.getSubOptions (prefix ++ ["<name>"]);
getSubModules = elemType.getSubModules;
substSubModules = m: attrsOf (elemType.substSubModules m);
functor = (defaultFunctor name) // { wrapped = elemType; };
nestedTypes.elemType = elemType;
};
# A version of attrsOf that's lazy in its values at the expense of
# conditional definitions not working properly. E.g. defining a value with
# `foo.attr = mkIf false 10`, then `foo ? attr == true`, whereas with
# attrsOf it would correctly be `false`. Accessing `foo.attr` would throw an
# error that it's not defined. Use only if conditional definitions don't make sense.
lazyAttrsOf = elemType: mkOptionType rec {
name = "lazyAttrsOf";
description = "lazy attribute set of ${elemType.description}s";
check = isAttrs;
merge = loc: defs:
zipAttrsWith (name: defs:
let merged = mergeDefinitions (loc ++ [name]) elemType defs;
# mergedValue will trigger an appropriate error when accessed
in merged.optionalValue.value or elemType.emptyValue.value or merged.mergedValue
)
# Push down position info.
(map (def: mapAttrs (n: v: { inherit (def) file; value = v; }) def.value) defs);
emptyValue = { value = {}; };
getSubOptions = prefix: elemType.getSubOptions (prefix ++ ["<name>"]);
getSubModules = elemType.getSubModules;
substSubModules = m: lazyAttrsOf (elemType.substSubModules m);
functor = (defaultFunctor name) // { wrapped = elemType; };
nestedTypes.elemType = elemType;
};
# TODO: drop this in the future:
loaOf = elemType: types.attrsOf elemType // {
name = "loaOf";
deprecationMessage = "Mixing lists with attribute values is no longer"
+ " possible; please use `types.attrsOf` instead. See"
+ " https://github.com/NixOS/nixpkgs/issues/1800 for the motivation.";
nestedTypes.elemType = elemType;
};
# Value of given type but with no merging (i.e. `uniq list`s are not concatenated).
uniq = elemType: mkOptionType rec {
name = "uniq";
inherit (elemType) description check;
merge = mergeOneOption;
emptyValue = elemType.emptyValue;
getSubOptions = elemType.getSubOptions;
getSubModules = elemType.getSubModules;
substSubModules = m: uniq (elemType.substSubModules m);
functor = (defaultFunctor name) // { wrapped = elemType; };
nestedTypes.elemType = elemType;
};
# Null or value of ...
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;
emptyValue = { value = null; };
getSubOptions = elemType.getSubOptions;
getSubModules = elemType.getSubModules;
substSubModules = m: nullOr (elemType.substSubModules m);
functor = (defaultFunctor name) // { wrapped = elemType; };
nestedTypes.elemType = elemType;
};
functionTo = elemType: mkOptionType {
name = "functionTo";
description = "function that evaluates to a(n) ${elemType.name}";
check = isFunction;
merge = loc: defs:
fnArgs: (mergeDefinitions (loc ++ [ "[function body]" ]) elemType (map (fn: { inherit (fn) file; value = fn.value fnArgs; }) defs)).mergedValue;
getSubOptions = elemType.getSubOptions;
getSubModules = elemType.getSubModules;
substSubModules = m: functionTo (elemType.substSubModules m);
};
# A submodule (like typed attribute set). See NixOS manual.
submodule = modules: submoduleWith {
shorthandOnlyDefinesConfig = true;
modules = toList modules;
};
submoduleWith =
{ modules
, specialArgs ? {}
, shorthandOnlyDefinesConfig ? false
}@attrs:
let
inherit (lib.modules) evalModules;
coerce = unify: value: if isFunction value
then setFunctionArgs (args: unify (value args)) (functionArgs value)
else unify (if shorthandOnlyDefinesConfig then { config = value; } else value);
allModules = defs: modules ++ imap1 (n: { value, file }:
if isAttrs value || isFunction value then
# Annotate the value with the location of its definition for better error messages
coerce (lib.modules.unifyModuleSyntax file "${toString file}-${toString n}") value
else value
) defs;
freeformType = (evalModules {
inherit modules specialArgs;
args.name = "name";
})._module.freeformType;
in
mkOptionType rec {
name = "submodule";
description = freeformType.description or name;
check = x: isAttrs x || isFunction x || path.check x;
merge = loc: defs:
(evalModules {
modules = allModules defs;
inherit specialArgs;
args.name = last loc;
prefix = loc;
}).config;
emptyValue = { value = {}; };
getSubOptions = prefix: (evalModules
{ inherit modules prefix specialArgs;
# This is a work-around due to the fact that some sub-modules,
# such as the one included in an attribute set, expects a "args"
# attribute to be given to the sub-module. As the option
# evaluation does not have any specific attribute name, we
# provide a default one for the documentation.
#
# This is mandatory as some option declaration might use the
# "name" attribute given as argument of the submodule and use it
# as the default of option declarations.
#
# Using lookalike unicode single angle quotation marks because
# of the docbook transformation the options receive. In all uses
# &gt; and &lt; wouldn't be encoded correctly so the encoded values
# would be used, and use of `<` and `>` would break the XML document.
# It shouldn't cause an issue since this is cosmetic for the manual.
args.name = "name";
}).options // optionalAttrs (freeformType != null) {
# Expose the sub options of the freeform type. Note that the option
# discovery doesn't care about the attribute name used here, so this
# is just to avoid conflicts with potential options from the submodule
_freeformOptions = freeformType.getSubOptions prefix;
};
getSubModules = modules;
substSubModules = m: submoduleWith (attrs // {
modules = m;
});
nestedTypes = lib.optionalAttrs (freeformType != null) {
freeformType = freeformType;
};
functor = defaultFunctor name // {
type = types.submoduleWith;
payload = {
modules = modules;
specialArgs = specialArgs;
shorthandOnlyDefinesConfig = shorthandOnlyDefinesConfig;
};
binOp = lhs: rhs: {
modules = lhs.modules ++ rhs.modules;
specialArgs =
let intersecting = builtins.intersectAttrs lhs.specialArgs rhs.specialArgs;
in if intersecting == {}
then lhs.specialArgs // rhs.specialArgs
else throw "A submoduleWith option is declared multiple times with the same specialArgs \"${toString (attrNames intersecting)}\"";
shorthandOnlyDefinesConfig =
if lhs.shorthandOnlyDefinesConfig == rhs.shorthandOnlyDefinesConfig
then lhs.shorthandOnlyDefinesConfig
else throw "A submoduleWith option is declared multiple times with conflicting shorthandOnlyDefinesConfig values";
};
};
};
# A value from a set of allowed ones.
enum = values:
let
show = v:
if builtins.isString v then ''"${v}"''
else if builtins.isInt v then builtins.toString v
else if builtins.isBool v then boolToString v
else ''<${builtins.typeOf v}>'';
in
mkOptionType rec {
name = "enum";
description = "one of ${concatMapStringsSep ", " show values}";
check = flip elem values;
merge = mergeEqualOption;
functor = (defaultFunctor name) // { payload = values; binOp = a: b: unique (a ++ b); };
};
# Either value of type `t1` or `t2`.
either = t1: t2: mkOptionType rec {
name = "either";
description = "${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 ]; };
nestedTypes.left = t1;
nestedTypes.right = t2;
};
# Any of the types in the given list
oneOf = ts:
let
head' = if ts == [] then throw "types.oneOf needs to get at least one type in its argument" else head ts;
tail' = tail ts;
in foldl' either head' tail';
# Either value of type `coercedType` or `finalType`, the former is
# converted to `finalType` using `coerceFunc`.
coercedTo = coercedType: coerceFunc: finalType:
assert lib.assertMsg (coercedType.getSubModules == null)
"coercedTo: coercedType must not have submodules (its a ${
coercedType.description})";
mkOptionType rec {
name = "coercedTo";
description = "${finalType.description} or ${coercedType.description} convertible to it";
check = x: (coercedType.check x && finalType.check (coerceFunc x)) || finalType.check x;
merge = loc: defs:
let
coerceVal = val:
if coercedType.check val then coerceFunc val
else val;
in finalType.merge loc (map (def: def // { value = coerceVal def.value; }) defs);
emptyValue = finalType.emptyValue;
getSubOptions = finalType.getSubOptions;
getSubModules = finalType.getSubModules;
substSubModules = m: coercedTo coercedType coerceFunc (finalType.substSubModules m);
typeMerge = t1: t2: null;
functor = (defaultFunctor name) // { wrapped = finalType; };
nestedTypes.coercedType = coercedType;
nestedTypes.finalType = finalType;
};
# Obsolete alternative to configOf. It takes its option
# declarations from the options attribute of containing option
# declaration.
optionSet = mkOptionType {
name = "optionSet";
description = "option set";
deprecationMessage = "Use `types.submodule' instead";
};
# Augment the given type with an additional type check function.
addCheck = elemType: check: elemType // { check = x: elemType.check x && check x; };
};
};
in outer_types // outer_types.types