119 lines
		
	
	
		
			4.1 KiB
		
	
	
	
		
			Nix
		
	
	
	
	
	
			
		
		
	
	
			119 lines
		
	
	
		
			4.1 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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| 
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| rec {
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| 
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| 
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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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| 
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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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| 
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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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| 
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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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|      
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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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| 
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| 
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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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|           overrideDerivation = fdrv:
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|             makeOverridable (args: overrideDerivation (f args) fdrv) origArgs;
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|         })
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|       else ff;
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| 
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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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| 
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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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|       commonAttrs = drv // (builtins.listToAttrs outputsList) //
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|         ({ all = map (x: x.value) outputsList; }) // passthru;
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| 
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|       outputToAttrListElement = outputName:
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|         { name = outputName;
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|           value = commonAttrs // {
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|             inherit (drv.${outputName}) outPath drvPath type outputName;
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|           };
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|         };
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| 
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|       outputsList = map outputToAttrListElement outputs;
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|   in commonAttrs.${drv.outputName};
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| }
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