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nixpkgs/lib/meta.nix
2021-04-02 19:20:23 +08:00

103 lines
2.8 KiB
Nix

/* Some functions for manipulating meta attributes, as well as the
name attribute. */
{ lib }:
rec {
/* Add to or override the meta attributes of the given
derivation.
Example:
addMetaAttrs {description = "Bla blah";} somePkg
*/
addMetaAttrs = newAttrs: drv:
drv // { meta = (drv.meta or {}) // newAttrs; };
/* Disable Hydra builds of given derivation.
*/
dontDistribute = drv: addMetaAttrs { hydraPlatforms = []; } drv;
/* Change the symbolic name of a package for presentation purposes
(i.e., so that nix-env users can tell them apart).
*/
setName = name: drv: drv // {inherit name;};
/* Like `setName', but takes the previous name as an argument.
Example:
updateName (oldName: oldName + "-experimental") somePkg
*/
updateName = updater: drv: drv // {name = updater (drv.name);};
/* Append a suffix to the name of a package (before the version
part). */
appendToName = suffix: updateName (name:
let x = builtins.parseDrvName name; in "${x.name}-${suffix}-${x.version}");
/* Apply a function to each derivation and only to derivations in an attrset.
*/
mapDerivationAttrset = f: set: lib.mapAttrs (name: pkg: if lib.isDerivation pkg then (f pkg) else pkg) set;
/* Set the nix-env priority of the package.
*/
setPrio = priority: addMetaAttrs { inherit priority; };
/* Decrease the nix-env priority of the package, i.e., other
versions/variants of the package will be preferred.
*/
lowPrio = setPrio 10;
/* Apply lowPrio to an attrset with derivations
*/
lowPrioSet = set: mapDerivationAttrset lowPrio set;
/* Increase the nix-env priority of the package, i.e., this
version/variant of the package will be preferred.
*/
hiPrio = setPrio (-10);
/* Apply hiPrio to an attrset with derivations
*/
hiPrioSet = set: mapDerivationAttrset hiPrio set;
/* Check to see if a platform is matched by the given `meta.platforms`
element.
A `meta.platform` pattern is either
1. (legacy) a system string.
2. (modern) a pattern for the platform `parsed` field.
We can inject these into a patten for the whole of a structured platform,
and then match that.
*/
platformMatch = platform: elem: let
pattern =
if builtins.isString elem
then { system = elem; }
else { parsed = elem; };
in lib.matchAttrs pattern platform;
/* Check if a package is available on a given platform.
A package is available on a platform if both
1. One of `meta.platforms` pattern matches the given platform.
2. None of `meta.badPlatforms` pattern matches the given platform.
*/
availableOn = platform: pkg:
lib.any (platformMatch platform) pkg.meta.platforms &&
lib.all (elem: !platformMatch platform elem) (pkg.meta.badPlatforms or []);
}