3 files changed, 190 insertions, 0 deletions

diff --git a/nix/README.md b/nix/README.md
new file mode 100644
index 00000000..7bf996c4
--- /dev/null
+++ b/nix/README.md
@@ -0,0 +1,2 @@
+This directory is handled by niv, but it prefers to have a directory
+named "nix"
diff --git a/nix/sources.json b/nix/sources.json
new file mode 100644
index 00000000..fb0e7d63
--- /dev/null
+++ b/nix/sources.json
@@ -0,0 +1,53 @@
+{
+    "niv": {
+        "branch": "master",
+        "description": "Easy dependency management for Nix projects",
+        "homepage": "https://github.com/nmattia/niv",
+        "owner": "nmattia",
+        "repo": "niv",
+        "rev": "372f96bff217a7a019de27667d04118cffa9841b",
+        "sha256": "1l0z6162zw60pdcdj03aq64qgf1vyzmf24i9pxca64i4sprl1b7p",
+        "type": "tarball",
+        "url": "https://github.com/nmattia/niv/archive/372f96bff217a7a019de27667d04118cffa9841b.tar.gz",
+        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
+    },
+    "nixpkgs-env": {
+        "branch": "nixos-19.03",
+        "description": "A read-only mirror of NixOS/nixpkgs tracking the released channels. Send issues and PRs to",
+        "homepage": "https://github.com/NixOS/nixpkgs",
+        "owner": "NixOS",
+        "repo": "nixpkgs-channels",
+        "rev": "34c7eb7545d155cc5b6f499b23a7cb1c96ab4d59",
+        "sha256": "11z6ajj108fy2q5g8y4higlcaqncrbjm3dnv17pvif6avagw4mcb",
+        "type": "tarball",
+        "url": "https://github.com/NixOS/nixpkgs-channels/archive/34c7eb7545d155cc5b6f499b23a7cb1c96ab4d59.tar.gz",
+        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
+    },
+    "nixpkgs-nixops": {
+        "channel_link": "https://nixos.org/channels/nixos-19.03",
+        "revision": "173677.daf861a810d",
+        "sha256": "0v5bhdiyg1xv1dzsy7jbm301ighsvmi87wibw96iiky8sqs6qd4z",
+        "type": "tarball",
+        "url": "https://releases.nixos.org/nixos/19.03/nixos-19.03.173677.daf861a810d/nixexprs.tar.xz",
+        "url_template": "https://releases.nixos.org/nixos/<version>/nixos-<version>.<revision>/nixexprs.tar.xz",
+        "version": "19.03"
+    },
+    "nixpkgs-nixops-previous": {
+        "channel_link": "https://nixos.org/channels/nixos-19.03",
+        "revision": "173677.daf861a810d",
+        "sha256": "0v5bhdiyg1xv1dzsy7jbm301ighsvmi87wibw96iiky8sqs6qd4z",
+        "type": "tarball",
+        "url": "https://releases.nixos.org/nixos/19.03/nixos-19.03.173677.daf861a810d/nixexprs.tar.xz",
+        "url_template": "https://releases.nixos.org/nixos/<version>/nixos-<version>.<revision>/nixexprs.tar.xz",
+        "version": "19.03"
+    },
+    "nixpkgs-nixops-next": {
+        "channel_link": "https://nixos.org/channels/nixos-19.03",
+        "revision": "173677.daf861a810d",
+        "sha256": "0v5bhdiyg1xv1dzsy7jbm301ighsvmi87wibw96iiky8sqs6qd4z",
+        "type": "tarball",
+        "url": "https://releases.nixos.org/nixos/19.03/nixos-19.03.173677.daf861a810d/nixexprs.tar.xz",
+        "url_template": "https://releases.nixos.org/nixos/<version>/nixos-<version>.<revision>/nixexprs.tar.xz",
+        "version": "19.03"
+    }
+}
diff --git a/nix/sources.nix b/nix/sources.nix
new file mode 100644
index 00000000..45c97d10
--- /dev/null
+++ b/nix/sources.nix
@@ -0,0 +1,135 @@
+# This file has been generated by Niv.
+
+let
+
+  #
+  # The fetchers. fetch_<type> fetches specs of type <type>.
+  #
+
+  fetch_file = pkgs: spec:
+    if spec.builtin or true then
+      builtins_fetchurl { inherit (spec) url sha256; }
+    else
+      pkgs.fetchurl { inherit (spec) url sha256; };
+
+  fetch_tarball = pkgs: name: spec:
+    let
+      ok = str: ! builtins.isNull (builtins.match "[a-zA-Z0-9+-._?=]" str);
+      # sanitize the name, though nix will still fail if name starts with period
+      name' = stringAsChars (x: if ! ok x then "-" else x) "${name}-src";
+    in
+      if spec.builtin or true then
+        builtins_fetchTarball { name = name'; inherit (spec) url sha256; }
+      else
+        pkgs.fetchzip { name = name'; inherit (spec) url sha256; };
+
+  fetch_git = spec:
+    builtins.fetchGit { url = spec.repo; inherit (spec) rev ref; };
+
+  fetch_builtin-tarball = name: throw
+    ''[${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
+  #
+
+  # The set of packages used when specs are fetched using non-builtins.
+  mkPkgs = sources:
+    let
+      sourcesNixpkgs =
+        import (builtins_fetchTarball { inherit (sources.nixpkgs) url sha256; }) {};
+      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 spec
+    else if spec.type == "tarball" then fetch_tarball pkgs name spec
+    else if spec.type == "git" then fetch_git 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 ${builtins.toJSON spec.type}";
+
+  # Ports of functions for older nix versions
+
+  # a Nix version of mapAttrs if the built-in doesn't exist
+  mapAttrs = builtins.mapAttrs or (
+    f: set: with builtins;
+    listToAttrs (map (attr: { name = attr; value = f attr set.${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));
+  concatStrings = builtins.concatStringsSep "";
+
+  # fetchTarball version that is compatible between all the versions of Nix
+  builtins_fetchTarball = { url, name, sha256 }@attrs:
+    let
+      inherit (builtins) lessThan nixVersion fetchTarball;
+    in
+      if lessThan nixVersion "1.12" then
+        fetchTarball { inherit name url; }
+      else
+        fetchTarball attrs;
+
+  # fetchurl version that is compatible between all the versions of Nix
+  builtins_fetchurl = { url, sha256 }@attrs:
+    let
+      inherit (builtins) lessThan nixVersion fetchurl;
+    in
+      if lessThan nixVersion "1.12" then
+        fetchurl { inherit url; }
+      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 = fetch config.pkgs name spec; }
+    ) config.sources;
+
+  # The "config" used by the fetchers
+  mkConfig =
+    { sourcesFile ? ./sources.json
+    , sources ? builtins.fromJSON (builtins.readFile sourcesFile)
+    , pkgs ? mkPkgs sources
+    }: 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); }