97220c973f
For NixOS evaluation, this gives a ~21% reduction in the number of values allocated and a ~4% speedup. It's also more readable.
117 lines
4 KiB
Nix
117 lines
4 KiB
Nix
let
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lib = import ./default.nix;
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inherit (builtins) attrNames isFunction;
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in
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rec {
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/* `overrideDerivation drv f' takes a derivation (i.e., the result
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of a call to the builtin function `derivation') and returns a new
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derivation in which the attributes of the original are overriden
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according to the function `f'. The function `f' is called with
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the original derivation attributes.
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`overrideDerivation' allows certain "ad-hoc" customisation
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scenarios (e.g. in ~/.nixpkgs/config.nix). For instance, if you
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want to "patch" the derivation returned by a package function in
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Nixpkgs to build another version than what the function itself
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provides, you can do something like this:
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mySed = overrideDerivation pkgs.gnused (oldAttrs: {
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name = "sed-4.2.2-pre";
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src = fetchurl {
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url = ftp://alpha.gnu.org/gnu/sed/sed-4.2.2-pre.tar.bz2;
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sha256 = "11nq06d131y4wmf3drm0yk502d2xc6n5qy82cg88rb9nqd2lj41k";
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};
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patches = [];
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});
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For another application, see build-support/vm, where this
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function is used to build arbitrary derivations inside a QEMU
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virtual machine. */
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overrideDerivation = drv: f:
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let
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newDrv = derivation (drv.drvAttrs // (f drv));
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in addPassthru newDrv (
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{ meta = drv.meta or {};
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passthru = if drv ? passthru then drv.passthru else {};
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}
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//
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(drv.passthru or {})
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//
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(if (drv ? crossDrv && drv ? nativeDrv)
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then {
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crossDrv = overrideDerivation drv.crossDrv f;
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nativeDrv = overrideDerivation drv.nativeDrv f;
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}
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else { }));
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# usage: (you can use override multiple times)
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# let d = makeOverridable stdenv.mkDerivation { name = ..; buildInputs; }
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# noBuildInputs = d.override { buildInputs = []; }
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# additionalBuildInputs = d.override ( args : args // { buildInputs = args.buildInputs ++ [ additional ]; } )
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makeOverridable = f: origArgs:
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let
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ff = f origArgs;
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in
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if builtins.isAttrs ff then (ff //
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{ override = newArgs:
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makeOverridable f (origArgs // (if builtins.isFunction newArgs then newArgs origArgs else newArgs));
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deepOverride = newArgs:
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makeOverridable f (lib.overrideExisting (lib.mapAttrs (deepOverrider newArgs) origArgs) newArgs);
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})
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else ff;
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deepOverrider = newArgs: name: x: if builtins.isAttrs x then (
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if x ? deepOverride then (x.deepOverride newArgs) else
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if x ? override then (x.override newArgs) else
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x) else x;
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/* Call the package function in the file `fn' with the required
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arguments automatically. The function is called with the
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arguments `args', but any missing arguments are obtained from
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`autoArgs'. This function is intended to be partially
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parameterised, e.g.,
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callPackage = callPackageWith pkgs;
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pkgs = {
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libfoo = callPackage ./foo.nix { };
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libbar = callPackage ./bar.nix { };
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};
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If the `libbar' function expects an argument named `libfoo', it is
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automatically passed as an argument. Overrides or missing
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arguments can be supplied in `args', e.g.
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libbar = callPackage ./bar.nix {
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libfoo = null;
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enableX11 = true;
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};
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*/
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callPackageWith = autoArgs: fn: args:
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let f = if builtins.isFunction fn then fn else import fn; in
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makeOverridable f ((builtins.intersectAttrs (builtins.functionArgs f) autoArgs) // args);
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/* Add attributes to each output of a derivation without changing the derivation itself */
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addPassthru = drv: passthru:
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let
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outputs = drv.outputs or [ "out" ];
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commonAttrs = drv // (builtins.listToAttrs outputsList) //
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({ all = map (x: x.value) outputsList; }) // passthru;
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outputToAttrListElement = outputName:
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{ name = outputName;
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value = commonAttrs // {
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inherit (drv.${outputName}) outPath drvPath type outputName;
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};
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};
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outputsList = map outputToAttrListElement outputs;
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in commonAttrs.${drv.outputName};
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}
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