From 834d7d56c9e6973d092729e1d7af40f3f28607ec Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?F=C3=A9lix=20Baylac=20Jacqu=C3=A9?=
 <felix@alternativebit.fr>
Date: Tue, 22 Nov 2022 10:23:20 +0100
Subject: [PATCH] Add Nix build infrastructure

---
 default.nix          | 30 +++++++++++++++++++++++
 flake.lock           | 27 +++++++++++++++++++++
 flake.nix            | 28 ++++++++++++++++++++++
 nixglhost-wrapper.py | 57 ++++++++++++++++++++++++++++++++++++++++++++
 shell.nix            |  9 +++++++
 5 files changed, 151 insertions(+)
 create mode 100644 default.nix
 create mode 100644 flake.lock
 create mode 100644 flake.nix
 create mode 100755 nixglhost-wrapper.py
 create mode 100644 shell.nix

diff --git a/default.nix b/default.nix
new file mode 100644
index 0000000..29fe6cb
--- /dev/null
+++ b/default.nix
@@ -0,0 +1,30 @@
+{ pkgs ? import <nixpkgs> { }, lib ? pkgs.lib }:
+
+pkgs.stdenvNoCC.mkDerivation {
+  pname = "nix-gl-host";
+  version = "0.1";
+  # TODO: filter that out
+  src = lib.cleanSource ./.;
+  nativeBuildInputs = [
+    pkgs.nixpkgs-fmt
+    pkgs.python3
+    pkgs.python3Packages.black
+    pkgs.nixpkgs-fmt
+  ];
+
+  postFixup = ''
+    substituteInPlace $out/bin/nixglhost \
+        --replace "@patchelf-bin@" "${pkgs.patchelf}/bin/patchelf" \
+        --replace "IN_NIX_STORE = False" "IN_NIX_STORE = True"
+    patchShebangs $out/bin/nixglhost
+  '';
+
+  postCheck = ''
+    black --check $out/bin/nixglhost
+    nixpkgs-fmt --check *.nix
+  '';
+
+  installPhase = ''
+    install -D -m0755 nixglhost-wrapper.py $out/bin/nixglhost
+  '';
+}
diff --git a/flake.lock b/flake.lock
new file mode 100644
index 0000000..5887140
--- /dev/null
+++ b/flake.lock
@@ -0,0 +1,27 @@
+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1669045945,
+        "narHash": "sha256-BQxzijvZpLQ7R+KuQzCPcFgIS6OK0Onb29pYFe2pzJo=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "6b5019a48f876f3288efc626fa8b70ad0c64eb46",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixpkgs-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}
diff --git a/flake.nix b/flake.nix
new file mode 100644
index 0000000..065de7d
--- /dev/null
+++ b/flake.nix
@@ -0,0 +1,28 @@
+{
+  description = "Gluing native OpenGL drivers";
+  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+  outputs =
+    { self
+    , nixpkgs
+    }:
+    let
+      systems = [
+        "x86_64-linux"
+        "aarch64-linux"
+      ];
+      forAllSystems = f: nixpkgs.lib.genAttrs systems (system: f system);
+    in
+    {
+      defaultPackage = forAllSystems (system:
+        import ./default.nix {
+          pkgs = import nixpkgs { inherit system; };
+        });
+      devShell = forAllSystems (system:
+        nixpkgs.legacyPackages.${system}.callPackage ./shell.nix { }
+      );
+
+      formatter = forAllSystems (system:
+        nixpkgs.legacyPackages.${system}.nixpkgs-fmt
+      );
+    };
+}
diff --git a/nixglhost-wrapper.py b/nixglhost-wrapper.py
new file mode 100755
index 0000000..eb14b08
--- /dev/null
+++ b/nixglhost-wrapper.py
@@ -0,0 +1,57 @@
+#!/usr/bin/env python3
+import argparse
+import os
+import sys
+
+IN_NIX_STORE = False
+
+if IN_NIX_STORE:
+    # The following paths are meant to be substituted by Nix at build
+    # time.
+    PATCHELF_PATH = "@patchelf-bin@"
+else:
+    PATCHELF_PATH = "patchelf"
+
+
+def info_debug(string):
+    """Prints STR to STDERR if the DEBUG environment variable is set"""
+    if "DEBUG" in os.environ:
+        print(f"[+] {string}", file=sys.stderr)
+
+
+def patch_dso(dsoPath, ):
+    raise "TODO patch_dso"
+
+
+def find_vendor_dso():
+    raise "TODO find_vendor_dso"
+
+
+def exec_binary(args):
+    raise "TODO exec_binary"
+
+
+def main(args):
+    home = os.path.expanduser("~")
+    xdg_cache_home = os.environ.get("XDG_CACHE_HOME", os.path.join(HOME, ".cache"))
+    os.exit(0)
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(
+        prog="nixglhost-wrapper",
+        description="Wrapper used to massage the host GL drivers to work with your nix-built binary.",
+    )
+    parser.add_argument(
+        "GL_VENDOR_PATH",
+        type=str,
+        help="a path pointing to the directory containing your GL driver shared libraries",
+    )
+    parser.add_argument(
+        "NIX_BINARY_AND_ARGS",
+        type=str,
+        nargs="+",
+        help="Nix-built binary you'd like to wrap and its args. For instance: nixglhost-wrapper /usr/lib/nvidia opengl-exe --with --some --args",
+    )
+    args = parser.parse_args()
+    main()
diff --git a/shell.nix b/shell.nix
new file mode 100644
index 0000000..7d88dab
--- /dev/null
+++ b/shell.nix
@@ -0,0 +1,9 @@
+{ pkgs ? import <nixpkgs> { } }:
+
+pkgs.mkShell {
+  nativeBuildInputs = [
+    pkgs.nixpkgs-fmt
+    pkgs.python3Packages.black
+    pkgs.python3Packages.mypy
+  ];
+}