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nixify
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BrianHicks committed May 10, 2021
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1 change: 1 addition & 0 deletions .envrc
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use nix
26 changes: 26 additions & 0 deletions nix/sources.json
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{
"niv": {
"branch": "master",
"description": "Easy dependency management for Nix projects",
"homepage": "https://github.com/nmattia/niv",
"owner": "nmattia",
"repo": "niv",
"rev": "af958e8057f345ee1aca714c1247ef3ba1c15f5e",
"sha256": "1qjavxabbrsh73yck5dcq8jggvh3r2jkbr6b5nlz5d9yrqm9255n",
"type": "tarball",
"url": "https://github.com/nmattia/niv/archive/af958e8057f345ee1aca714c1247ef3ba1c15f5e.tar.gz",
"url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
},
"nixpkgs": {
"branch": "release-20.03",
"description": "Nix Packages collection",
"homepage": "",
"owner": "NixOS",
"repo": "nixpkgs",
"rev": "1db42b7fe3878f3f5f7a4f2dc210772fd080e205",
"sha256": "05k9y9ki6jhaqdhycnidnk5zrdzsdammbk5lsmsbz249hjhhgcgh",
"type": "tarball",
"url": "https://github.com/NixOS/nixpkgs/archive/1db42b7fe3878f3f5f7a4f2dc210772fd080e205.tar.gz",
"url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
}
}
174 changes: 174 additions & 0 deletions nix/sources.nix
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# This file has been generated by Niv.

let

#
# The fetchers. fetch_<type> fetches specs of type <type>.
#

fetch_file = pkgs: name: spec:
let
name' = sanitizeName name + "-src";
in
if spec.builtin or true then
builtins_fetchurl { inherit (spec) url sha256; name = name'; }
else
pkgs.fetchurl { inherit (spec) url sha256; name = name'; };

fetch_tarball = pkgs: name: spec:
let
name' = sanitizeName name + "-src";
in
if spec.builtin or true then
builtins_fetchTarball { name = name'; inherit (spec) url sha256; }
else
pkgs.fetchzip { name = name'; inherit (spec) url sha256; };

fetch_git = name: spec:
let
ref =
if spec ? ref then spec.ref else
if spec ? branch then "refs/heads/${spec.branch}" else
if spec ? tag then "refs/tags/${spec.tag}" else
abort "In git source '${name}': Please specify `ref`, `tag` or `branch`!";
in
builtins.fetchGit { url = spec.repo; inherit (spec) rev; inherit ref; };

fetch_local = spec: spec.path;

fetch_builtin-tarball = name: throw
''[${name}] The niv type "builtin-tarball" is deprecated. You should instead use `builtin = true`.
$ niv modify ${name} -a type=tarball -a builtin=true'';

fetch_builtin-url = name: throw
''[${name}] The niv type "builtin-url" will soon be deprecated. You should instead use `builtin = true`.
$ niv modify ${name} -a type=file -a builtin=true'';

#
# Various helpers
#

# https://github.com/NixOS/nixpkgs/pull/83241/files#diff-c6f540a4f3bfa4b0e8b6bafd4cd54e8bR695
sanitizeName = name:
(
concatMapStrings (s: if builtins.isList s then "-" else s)
(
builtins.split "[^[:alnum:]+._?=-]+"
((x: builtins.elemAt (builtins.match "\\.*(.*)" x) 0) name)
)
);

# The set of packages used when specs are fetched using non-builtins.
mkPkgs = sources: system:
let
sourcesNixpkgs =
import (builtins_fetchTarball { inherit (sources.nixpkgs) url sha256; }) { inherit system; };
hasNixpkgsPath = builtins.any (x: x.prefix == "nixpkgs") builtins.nixPath;
hasThisAsNixpkgsPath = <nixpkgs> == ./.;
in
if builtins.hasAttr "nixpkgs" sources
then sourcesNixpkgs
else if hasNixpkgsPath && ! hasThisAsNixpkgsPath then
import <nixpkgs> {}
else
abort
''
Please specify either <nixpkgs> (through -I or NIX_PATH=nixpkgs=...) or
add a package called "nixpkgs" to your sources.json.
'';

# The actual fetching function.
fetch = pkgs: name: spec:

if ! builtins.hasAttr "type" spec then
abort "ERROR: niv spec ${name} does not have a 'type' attribute"
else if spec.type == "file" then fetch_file pkgs name spec
else if spec.type == "tarball" then fetch_tarball pkgs name spec
else if spec.type == "git" then fetch_git name spec
else if spec.type == "local" then fetch_local spec
else if spec.type == "builtin-tarball" then fetch_builtin-tarball name
else if spec.type == "builtin-url" then fetch_builtin-url name
else
abort "ERROR: niv spec ${name} has unknown type ${builtins.toJSON spec.type}";

# If the environment variable NIV_OVERRIDE_${name} is set, then use
# the path directly as opposed to the fetched source.
replace = name: drv:
let
saneName = stringAsChars (c: if isNull (builtins.match "[a-zA-Z0-9]" c) then "_" else c) name;
ersatz = builtins.getEnv "NIV_OVERRIDE_${saneName}";
in
if ersatz == "" then drv else
# this turns the string into an actual Nix path (for both absolute and
# relative paths)
if builtins.substring 0 1 ersatz == "/" then /. + ersatz else /. + builtins.getEnv "PWD" + "/${ersatz}";

# Ports of functions for older nix versions

# a Nix version of mapAttrs if the built-in doesn't exist
mapAttrs = builtins.mapAttrs or (
f: set: with builtins;
listToAttrs (map (attr: { name = attr; value = f attr set.${attr}; }) (attrNames set))
);

# https://github.com/NixOS/nixpkgs/blob/0258808f5744ca980b9a1f24fe0b1e6f0fecee9c/lib/lists.nix#L295
range = first: last: if first > last then [] else builtins.genList (n: first + n) (last - first + 1);

# https://github.com/NixOS/nixpkgs/blob/0258808f5744ca980b9a1f24fe0b1e6f0fecee9c/lib/strings.nix#L257
stringToCharacters = s: map (p: builtins.substring p 1 s) (range 0 (builtins.stringLength s - 1));

# https://github.com/NixOS/nixpkgs/blob/0258808f5744ca980b9a1f24fe0b1e6f0fecee9c/lib/strings.nix#L269
stringAsChars = f: s: concatStrings (map f (stringToCharacters s));
concatMapStrings = f: list: concatStrings (map f list);
concatStrings = builtins.concatStringsSep "";

# https://github.com/NixOS/nixpkgs/blob/8a9f58a375c401b96da862d969f66429def1d118/lib/attrsets.nix#L331
optionalAttrs = cond: as: if cond then as else {};

# fetchTarball version that is compatible between all the versions of Nix
builtins_fetchTarball = { url, name ? null, sha256 }@attrs:
let
inherit (builtins) lessThan nixVersion fetchTarball;
in
if lessThan nixVersion "1.12" then
fetchTarball ({ inherit url; } // (optionalAttrs (!isNull name) { inherit name; }))
else
fetchTarball attrs;

# fetchurl version that is compatible between all the versions of Nix
builtins_fetchurl = { url, name ? null, sha256 }@attrs:
let
inherit (builtins) lessThan nixVersion fetchurl;
in
if lessThan nixVersion "1.12" then
fetchurl ({ inherit url; } // (optionalAttrs (!isNull name) { inherit name; }))
else
fetchurl attrs;

# Create the final "sources" from the config
mkSources = config:
mapAttrs (
name: spec:
if builtins.hasAttr "outPath" spec
then abort
"The values in sources.json should not have an 'outPath' attribute"
else
spec // { outPath = replace name (fetch config.pkgs name spec); }
) config.sources;

# The "config" used by the fetchers
mkConfig =
{ sourcesFile ? if builtins.pathExists ./sources.json then ./sources.json else null
, sources ? if isNull sourcesFile then {} else builtins.fromJSON (builtins.readFile sourcesFile)
, system ? builtins.currentSystem
, pkgs ? mkPkgs sources system
}: rec {
# The sources, i.e. the attribute set of spec name to spec
inherit sources;

# The "pkgs" (evaluated nixpkgs) to use for e.g. non-builtin fetchers
inherit pkgs;
};

in
mkSources (mkConfig {}) // { __functor = _: settings: mkSources (mkConfig settings); }
8 changes: 8 additions & 0 deletions shell.nix
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{ ... }:
let
sources = import ./nix/sources.nix;
pkgs = import sources.nixpkgs { };
niv = import sources.niv { };
in pkgs.mkShell {
buildInputs = with pkgs; [ niv.niv git python3 python3Packages.pip ];
}

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