feat: linux compatibility

[pikdum]

• tweaks to build and run natively on linux
• some small linter/warning fixes
• flake.nix for dev shell

Don't have Windows to verify that I didn't break that build, though.

I used this flake.nix to build libloot.so.0 v0.27.0 from https://github.com/loot/libloot:

{
  description = "Nix flake for building libloot (shared library)";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
  };

  outputs = { self, nixpkgs }:
    let
      lib = nixpkgs.lib;
      forAllSystems = lib.genAttrs [ "x86_64-linux" "aarch64-linux" ];
    in {
      packages = forAllSystems (system:
        let
          pkgs = import nixpkgs { inherit system; };

          espluginTarball = pkgs.fetchurl {
            url = "https://github.com/Ortham/esplugin/archive/refs/tags/6.1.3.tar.gz";
            hash = "sha256-0RNzuRCANujYRT/3cACuKWH50SQ8mcQt1zLa0Mg9hhg=";
          };

          libloadorderTarball = pkgs.fetchurl {
            url = "https://github.com/Ortham/libloadorder/archive/refs/tags/18.4.0.tar.gz";
            hash = "sha256-yD8fSIKeAT8mNAQbYv7YxJV/t0aaQBJQs3k5U+08PSw=";
          };

          lootConditionInterpreterTarball = pkgs.fetchurl {
            url = "https://github.com/loot/loot-condition-interpreter/archive/refs/tags/5.3.2.tar.gz";
            hash = "sha256-EaLGKJj2RQza5ttgfGP9eJj2K/Z9SHS3zu09NpMzGvM=";
          };

          yamlCppTarball = pkgs.fetchurl {
            url = "https://github.com/loot/yaml-cpp/archive/0.8.0+merge-key-support.3.tar.gz";
            hash = "sha256-4gZ/Grj2WK64qHlf0OBqdTtBULk1LK4EcoDmWQeN1E8=";
          };

          mkSource = name: tarball:
            pkgs.runCommand "${name}-source" { } ''
              mkdir -p "$out"
              tar -xzf ${tarball} --strip-components=1 -C "$out"
            '';

          mkFfiRustLibrary = {
            pname,
            version,
            src,
            cargoLockFile,
            manifestPath,
            staticLibName,
            cbindgenDir,
            cbindgenOutput,
            cbindgenArgs ? "",
          }:
            pkgs.rustPlatform.buildRustPackage {
              inherit pname version src;
              cargoLock.lockFile = cargoLockFile;
              cargoBuildFlags = [ "--manifest-path" manifestPath ];
              nativeBuildInputs = [ pkgs.rust-cbindgen ];
              doCheck = false;

              installPhase = ''
                runHook preInstall

                mkdir -p "$out/lib" "$out/include"
                staticLibPath=$(find target -type f -name "${staticLibName}" | head -n1)
                cp "$staticLibPath" "$out/lib/"
                cbindgen ${cbindgenArgs} ${cbindgenDir}/ -o "$out/include/${cbindgenOutput}"

                runHook postInstall
              '';
            };

          espluginSource = mkSource "esplugin-6.1.3" espluginTarball;
          libloadorderSource = mkSource "libloadorder-18.4.0" libloadorderTarball;
          lootConditionInterpreterSource = mkSource "loot-condition-interpreter-5.3.2" lootConditionInterpreterTarball;
          yamlCppSource = mkSource "yaml-cpp-0.8.0-merge-key-support.3" yamlCppTarball;

          espluginFfi = mkFfiRustLibrary {
            pname = "esplugin-ffi";
            version = "6.1.3";
            src = espluginSource;
            cargoLockFile = "${espluginSource}/Cargo.lock";
            manifestPath = "ffi/Cargo.toml";
            staticLibName = "libesplugin_ffi.a";
            cbindgenDir = "ffi";
            cbindgenOutput = "esplugin.hpp";
          };

          libloadorderFfi = mkFfiRustLibrary {
            pname = "libloadorder-ffi";
            version = "18.4.0";
            src = libloadorderSource;
            cargoLockFile = "${libloadorderSource}/Cargo.lock";
            manifestPath = "ffi/Cargo.toml";
            staticLibName = "libloadorder_ffi.a";
            cbindgenDir = "ffi";
            cbindgenOutput = "libloadorder.hpp";
            cbindgenArgs = "-l c++";
          };

          lootConditionInterpreterFfi = mkFfiRustLibrary {
            pname = "loot-condition-interpreter-ffi";
            version = "5.3.2";
            src = lootConditionInterpreterSource;
            cargoLockFile = "${lootConditionInterpreterSource}/Cargo.lock";
            manifestPath = "ffi/Cargo.toml";
            staticLibName = "libloot_condition_interpreter_ffi.a";
            cbindgenDir = "ffi";
            cbindgenOutput = "loot_condition_interpreter.h";
          };

          liblootPkg = pkgs.stdenv.mkDerivation {
            pname = "libloot";
            version = "0.27.0";

            src = ./.;
            strictDeps = true;
            preferLocalBuild = true;

            nativeBuildInputs = with pkgs; [
              cmake
              ninja
              pkg-config
              git
              python3
            ];

            buildInputs = with pkgs; [
              boost
              icu
              tbb
              fmt
              spdlog
            ];

            postPatch = ''
              python - <<'PY'
              from pathlib import Path

              path = Path("CMakeLists.txt")
              text = path.read_text()

              replacements = [
                  (
                      "if(NOT DEFINED ESPLUGIN_URL)",
                      "if(NOT (DEFINED ESPLUGIN_INCLUDE_DIRS AND DEFINED ESPLUGIN_LIBRARIES))\nif(NOT DEFINED ESPLUGIN_URL)",
                  ),
                  (
                      "if(NOT DEFINED LIBLOADORDER_URL)",
                      "endif()\n\nif(NOT (DEFINED LIBLOADORDER_INCLUDE_DIRS AND DEFINED LIBLOADORDER_LIBRARIES))\nif(NOT DEFINED LIBLOADORDER_URL)",
                  ),
                  (
                      "if(NOT DEFINED LOOT_CONDITION_INTERPRETER_URL)",
                      "endif()\n\nif(NOT (DEFINED LCI_INCLUDE_DIRS AND DEFINED LCI_LIBRARIES))\nif(NOT DEFINED LOOT_CONDITION_INTERPRETER_URL)",
                  ),
                  (
                      "FetchContent_Declare(\n    fmt",
                      "endif()\n\nFetchContent_Declare(\n    fmt",
                  ),
                  (
                      "add_dependencies(loot\n    esplugin\n    libloadorder\n    loot-condition-interpreter)",
                      "if(TARGET esplugin)\n    add_dependencies(loot esplugin)\nendif()\nif(TARGET libloadorder)\n    add_dependencies(loot libloadorder)\nendif()\nif(TARGET loot-condition-interpreter)\n    add_dependencies(loot loot-condition-interpreter)\nendif()",
                  ),
              ]

              for old, new in replacements:
                  if old not in text:
                      raise SystemExit(f"Patch pattern not found: {old!r}")
                  text = text.replace(old, new, 1)

              path.write_text(text)
              PY
            '';

            cmakeFlags = [
              "-DCMAKE_BUILD_TYPE=Release"
              "-DBUILD_SHARED_LIBS=ON"
              "-DLIBLOOT_BUILD_TESTS=OFF"
              "-DLIBLOOT_INSTALL_DOCS=OFF"

              "-DESPLUGIN_INCLUDE_DIRS=${espluginFfi}/include"
              "-DESPLUGIN_LIBRARIES=${espluginFfi}/lib/libesplugin_ffi.a;dl"

              "-DLIBLOADORDER_INCLUDE_DIRS=${libloadorderFfi}/include"
              "-DLIBLOADORDER_LIBRARIES=${libloadorderFfi}/lib/libloadorder_ffi.a;dl"

              "-DLCI_INCLUDE_DIRS=${lootConditionInterpreterFfi}/include"
              "-DLCI_LIBRARIES=${lootConditionInterpreterFfi}/lib/libloot_condition_interpreter_ffi.a;dl"

              "-DFETCHCONTENT_SOURCE_DIR_YAML-CPP=${yamlCppSource}"
            ];

            meta = with pkgs.lib; {
              description = "libloot shared library";
              homepage = "https://github.com/loot/libloot";
              license = licenses.gpl3Only;
              platforms = platforms.linux;
            };
          };
        in {
          libloot = liblootPkg;
          default = liblootPkg;
        });

      devShells = forAllSystems (system:
        let
          pkgs = import nixpkgs { inherit system; };
        in {
          default = pkgs.mkShell {
            packages = with pkgs; [
              cmake
              ninja
              pkg-config
              git
              rustc
              cargo
              rust-cbindgen
              boost
              icu
              tbb
              fmt
              spdlog
            ];
          };
        });
    };
}

That bit definitely seems over-complicated, probably simpler to use docker or their github actions. :)

[IDCs]

@Sewer56 - conflicts aside which are easy to fix, can you please test this on your end as I don't have a linux environment?

Can confirm this works just fine on Windows