Commit 09eb3c64 authored by nicoo's avatar nicoo
Browse files

lib.fetchers.normalizeHash: more implementation comment and clearer variable names

parent 0aa52428

lib/fetchers.nix

+12 −11
Original line number Diff line number Diff line
@@ -2,8 +2,8 @@ 
{ lib }:

let

  commonH = hashTypes: rec {

      hNames = [ "hash" ] ++ hashTypes;

      hAttrs = lib.genAttrs hNames (lib.const {});

      hashNames = [ "hash" ] ++ hashTypes;

      hashSet = lib.genAttrs hashNames (lib.const {});

  };



  fakeH = {
@@ -85,7 +85,7 @@ in rec { 
      inherit (lib) concatMapStringsSep head tail throwIf;

      inherit (lib.attrsets) attrsToList intersectAttrs removeAttrs optionalAttrs;



      inherit (commonH hashTypes) hAttrs hNames;

      inherit (commonH hashTypes) hashNames hashSet;

    in

      args:

        if args ? "outputHash" then
@@ -94,16 +94,17 @@ in rec { 
          let

            # The argument hash, as a {name, value} pair

            h =

              let _h = attrsToList (intersectAttrs hAttrs args); in

              if _h == [] then

              # All hashes passed in arguments (possibly 0 or >1) as a list of {name, value} pairs

              let hashesAsNVPairs = attrsToList (intersectAttrs hashSet args); in

              if hashesAsNVPairs == [] then

                throwIf required "fetcher called without `hash`" null

              else if tail _h != [] then

                throw "fetcher called with mutually-incompatible arguments: ${concatMapStringsSep ", " (a: a.name) _h}"

              else if tail hashesAsNVPairs != [] then

                throw "fetcher called with mutually-incompatible arguments: ${concatMapStringsSep ", " (a: a.name) hashesAsNVPairs}"

              else

                head _h

                head hashesAsNVPairs

            ;

          in

            removeAttrs args hNames // (optionalAttrs (h != null) {

            removeAttrs args hashNames // (optionalAttrs (h != null) {

              outputHashAlgo = if h.name == "hash" then null else h.name;

              outputHash =

                if h.value == "" then
@@ -170,7 +171,7 @@ in rec { 
      inherit (lib.attrsets) genAttrs intersectAttrs removeAttrs;

      inherit (lib.trivial) const functionArgs setFunctionArgs;



      inherit (commonH hashTypes) hAttrs;

      inherit (commonH hashTypes) hashSet;

      fArgs = functionArgs fetcher;



      normalize = normalizeHash {
@@ -180,7 +181,7 @@ in rec { 
    in

    # The o.g. fetcher must *only* accept outputHash and outputHashAlgo

    assert fArgs ? outputHash && fArgs ? outputHashAlgo;

    assert intersectAttrs fArgs hAttrs == {};

    assert intersectAttrs fArgs hashSet == {};



    setFunctionArgs

      (args: fetcher (normalize args))