nixpkgs/lib/gvariant.nix

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/*
A partial and basic implementation of GVariant formatted strings.
See [GVariant Format Strings](https://docs.gtk.org/glib/gvariant-format-strings.html) for details.
:::{.warning}
This API is not considered fully stable and it might therefore
change in backwards incompatible ways without prior notice.
:::
*/
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# This file is based on https://github.com/nix-community/home-manager
# Copyright (c) 2017-2022 Home Manager contributors
{ lib }:
let
inherit (lib)
concatMapStringsSep concatStrings escape head replaceStrings;
mkPrimitive = t: v: {
_type = "gvariant";
type = t;
value = v;
__toString = self: "@${self.type} ${toString self.value}"; # https://docs.gtk.org/glib/gvariant-text.html
};
type = {
arrayOf = t: "a${t}";
maybeOf = t: "m${t}";
tupleOf = ts: "(${concatStrings ts})";
dictionaryEntryOf = nameType: valueType: "{${nameType}${valueType}}";
string = "s";
boolean = "b";
uchar = "y";
int16 = "n";
uint16 = "q";
int32 = "i";
uint32 = "u";
int64 = "x";
uint64 = "t";
double = "d";
variant = "v";
};
/* Check if a value is a GVariant value
Type:
isGVariant :: Any -> Bool
*/
isGVariant = v: v._type or "" == "gvariant";
in
rec {
inherit type isGVariant;
intConstructors = [
{
name = "mkInt32";
type = type.int32;
min = -2147483648;
max = 2147483647;
}
{
name = "mkUint32";
type = type.uint32;
min = 0;
max = 4294967295;
}
{
name = "mkInt64";
type = type.int64;
# Nix does not support such large numbers.
min = null;
max = null;
}
{
name = "mkUint64";
type = type.uint64;
min = 0;
# Nix does not support such large numbers.
max = null;
}
{
name = "mkInt16";
type = type.int16;
min = -32768;
max = 32767;
}
{
name = "mkUint16";
type = type.uint16;
min = 0;
max = 65535;
}
{
name = "mkUchar";
type = type.uchar;
min = 0;
max = 255;
}
];
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/* Returns the GVariant value that most closely matches the given Nix value.
If no GVariant value can be found unambiguously then error is thrown.
Type:
mkValue :: Any -> gvariant
*/
mkValue = v:
if builtins.isBool v then
mkBoolean v
else if builtins.isFloat v then
mkDouble v
else if builtins.isString v then
mkString v
else if builtins.isList v then
mkArray v
else if isGVariant v then
v
else if builtins.isInt v then
let
validConstructors = builtins.filter ({ min, max, ... }: (min == null || min <= v) && (max == null || v <= max)) intConstructors;
in
throw ''
The GVariant type for number ${builtins.toString v} is unclear.
Please wrap the value with one of the following, depending on the value type in GSettings schema:
${lib.concatMapStringsSep "\n" ({ name, type, ...}: "- `lib.gvariant.${name}` for `${type}`") validConstructors}
''
else if builtins.isAttrs v then
throw "Cannot construct GVariant value from an attribute set. If you want to construct a dictionary, you will need to create an array containing items constructed with `lib.gvariant.mkDictionaryEntry`."
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else
throw "The GVariant type of ${builtins.typeOf v} can't be inferred.";
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/* Returns the GVariant array from the given type of the elements and a Nix list.
Type:
mkArray :: [Any] -> gvariant
Example:
# Creating a string array
lib.gvariant.mkArray [ "a" "b" "c" ]
*/
mkArray = elems:
let
vs = map mkValue (lib.throwIf (elems == [ ]) "Please create empty array with mkEmptyArray." elems);
elemType = lib.throwIfNot (lib.all (t: (head vs).type == t) (map (v: v.type) vs))
"Elements in a list should have same type."
(head vs).type;
in
mkPrimitive (type.arrayOf elemType) vs // {
__toString = self:
"@${self.type} [${concatMapStringsSep "," toString self.value}]";
};
/* Returns the GVariant array from the given empty Nix list.
Type:
mkEmptyArray :: gvariant.type -> gvariant
Example:
# Creating an empty string array
lib.gvariant.mkEmptyArray (lib.gvariant.type.string)
*/
mkEmptyArray = elemType: mkPrimitive (type.arrayOf elemType) [ ] // {
__toString = self: "@${self.type} []";
};
/* Returns the GVariant variant from the given Nix value. Variants are containers
of different GVariant type.
Type:
mkVariant :: Any -> gvariant
Example:
lib.gvariant.mkArray [
(lib.gvariant.mkVariant "a string")
(lib.gvariant.mkVariant (lib.gvariant.mkInt32 1))
]
*/
mkVariant = elem:
let gvarElem = mkValue elem;
in mkPrimitive type.variant gvarElem // {
__toString = self: "<${toString self.value}>";
};
/* Returns the GVariant dictionary entry from the given key and value.
Type:
mkDictionaryEntry :: String -> Any -> gvariant
Example:
# A dictionary describing an Epiphanys search provider
[
(lib.gvariant.mkDictionaryEntry "url" (lib.gvariant.mkVariant "https://duckduckgo.com/?q=%s&t=epiphany"))
(lib.gvariant.mkDictionaryEntry "bang" (lib.gvariant.mkVariant "!d"))
(lib.gvariant.mkDictionaryEntry "name" (lib.gvariant.mkVariant "DuckDuckGo"))
]
*/
mkDictionaryEntry =
# The key of the entry
name:
# The value of the entry
value:
let
name' = mkValue name;
value' = mkValue value;
dictionaryType = type.dictionaryEntryOf name'.type value'.type;
in
mkPrimitive dictionaryType { inherit name value; } // {
__toString = self: "@${self.type} {${name'},${value'}}";
};
/* Returns the GVariant maybe from the given element type.
Type:
mkMaybe :: gvariant.type -> Any -> gvariant
*/
mkMaybe = elemType: elem:
mkPrimitive (type.maybeOf elemType) elem // {
__toString = self:
if self.value == null then
"@${self.type} nothing"
else
"just ${toString self.value}";
};
/* Returns the GVariant nothing from the given element type.
Type:
mkNothing :: gvariant.type -> gvariant
*/
mkNothing = elemType: mkMaybe elemType null;
/* Returns the GVariant just from the given Nix value.
Type:
mkJust :: Any -> gvariant
*/
mkJust = elem: let gvarElem = mkValue elem; in mkMaybe gvarElem.type gvarElem;
/* Returns the GVariant tuple from the given Nix list.
Type:
mkTuple :: [Any] -> gvariant
*/
mkTuple = elems:
let
gvarElems = map mkValue elems;
tupleType = type.tupleOf (map (e: e.type) gvarElems);
in
mkPrimitive tupleType gvarElems // {
__toString = self:
"@${self.type} (${concatMapStringsSep "," toString self.value})";
};
/* Returns the GVariant boolean from the given Nix bool value.
Type:
mkBoolean :: Bool -> gvariant
*/
mkBoolean = v:
mkPrimitive type.boolean v // {
__toString = self: if self.value then "true" else "false";
};
/* Returns the GVariant string from the given Nix string value.
Type:
mkString :: String -> gvariant
*/
mkString = v:
let sanitize = s: replaceStrings [ "\n" ] [ "\\n" ] (escape [ "'" "\\" ] s);
in mkPrimitive type.string v // {
__toString = self: "'${sanitize self.value}'";
};
/* Returns the GVariant object path from the given Nix string value.
Type:
mkObjectpath :: String -> gvariant
*/
mkObjectpath = v:
mkPrimitive type.string v // {
__toString = self: "objectpath '${escape [ "'" ] self.value}'";
};
/* Returns the GVariant uchar from the given Nix int value.
Type:
mkUchar :: Int -> gvariant
*/
mkUchar = mkPrimitive type.uchar;
/* Returns the GVariant int16 from the given Nix int value.
Type:
mkInt16 :: Int -> gvariant
*/
mkInt16 = mkPrimitive type.int16;
/* Returns the GVariant uint16 from the given Nix int value.
Type:
mkUint16 :: Int -> gvariant
*/
mkUint16 = mkPrimitive type.uint16;
/* Returns the GVariant int32 from the given Nix int value.
Type:
mkInt32 :: Int -> gvariant
*/
mkInt32 = v:
mkPrimitive type.int32 v // {
__toString = self: toString self.value;
};
/* Returns the GVariant uint32 from the given Nix int value.
Type:
mkUint32 :: Int -> gvariant
*/
mkUint32 = mkPrimitive type.uint32;
/* Returns the GVariant int64 from the given Nix int value.
Type:
mkInt64 :: Int -> gvariant
*/
mkInt64 = mkPrimitive type.int64;
/* Returns the GVariant uint64 from the given Nix int value.
Type:
mkUint64 :: Int -> gvariant
*/
mkUint64 = mkPrimitive type.uint64;
/* Returns the GVariant double from the given Nix float value.
Type:
mkDouble :: Float -> gvariant
*/
mkDouble = v:
mkPrimitive type.double v // {
__toString = self: toString self.value;
};
}