add command line args

build.zig

@@ -46,6 +46,7 @@ pub fn build(b: *std.Build) void {
   const pixman = b.dependency("pixman", .{}).module("pixman");
   const wlroots = b.dependency("wlroots", .{}).module("wlroots");
   const zlua = b.dependency("zlua", .{}).module("zlua");
+  const clap = b.dependency("clap", .{}).module("clap");
 
   wlroots.addImport("wayland", wayland);
   wlroots.addImport("xkbcommon", xkbcommon);
@@ -69,14 +70,23 @@ pub fn build(b: *std.Build) void {
   mez.root_module.addImport("xkbcommon", xkbcommon);
   mez.root_module.addImport("wlroots", wlroots);
   mez.root_module.addImport("zlua", zlua);
+  mez.root_module.addImport("clap", clap);
 
   mez.linkSystemLibrary("wayland-server");
   mez.linkSystemLibrary("xkbcommon");
   mez.linkSystemLibrary("pixman-1");
   mez.linkSystemLibrary("libevdev");
 
+  var ret: u8 = undefined;
+  const version = b.runAllowFail(
+    &.{"git", "-C", b.build_root.path orelse ".", "describe", "--tags", "--dirty"},
+    &ret,
+    .Inherit,
+  ) catch "dev\n";
+
   const options = b.addOptions();
   options.addOption([]const u8, "runtime_path_prefix", runtime_path_prefix);
+  options.addOption([]const u8, "version", version);
   mez.root_module.addOptions("config", options);
 
   b.installArtifact(mez);

build.zig.zon

@@ -24,6 +24,10 @@
             .url = "git+https://github.com/natecraddock/ziglua#39f8df588d0864070deffa308ef575bf492777a0",
             .hash = "zlua-0.1.0-hGRpC6E9BQDBGKPqzmCRsI6Xd8jH9KohccmX69-L6HyS",
         },
+        .clap = .{
+            .url = "https://github.com/Hejsil/zig-clap/archive/refs/tags/0.11.0.tar.gz",
+            .hash = "clap-0.11.0-oBajB-HnAQDPCKYzwF7rO3qDFwRcD39Q0DALlTSz5H7e",
+        },
     },
     .paths = .{
         "build.zig",

runtime/share/mezzaluna/init.lua

@@ -12,5 +12,8 @@ package.path = package.path..";"..mez.fs.joinpath(mez.path.runtime, "?.lua")
 mez.inspect = require("inspect").inspect
 
 mez.path.base_config = mez.fs.joinpath(mez.path.runtime, "base_config.lua")
-mez.path.config = mez.fs.joinpath(env_conf, "mez", "init.lua")
-package.path = package.path..";"..mez.fs.joinpath(env_conf, "mez", "lua", "?.lua")
+
+if not mez.path.config then
+  mez.path.config = mez.fs.joinpath(env_conf, "mez", "init.lua")
+  package.path = package.path..";"..mez.fs.joinpath(env_conf, "mez", "lua", "?.lua")
+end

src/lua/Lua.zig

@@ -44,6 +44,34 @@ pub fn loadRuntimeDir(self: *zlua.Lua) !void {
   };
 }
 
+pub fn setBaseConfig(self: *zlua.Lua, path: []const u8) !void {
+  {
+    _ = try self.getGlobal("mez");
+    _ = self.getField(-1, "path");
+    defer self.pop(2);
+    const new_path = try std.fs.path.join(gpa, &[_][]const u8{path, "init.lua"});
+    defer gpa.free(new_path);
+    _ = self.pushString(new_path);
+    self.setField(-2, "config");
+  }
+  {
+    _ = try self.getGlobal("mez");
+    _ = self.getField(-1, "path");
+    defer self.pop(2);
+    const cur_path = self.toString(-1) catch "";
+
+    const unsentinel: []const u8 = std.mem.span(cur_path.ptr);
+    const new_path = try std.mem.concat(gpa, u8, &[_][]const u8{
+      unsentinel,
+      ";",
+      path,
+    });
+    defer gpa.free(new_path);
+    _ = self.pushString(new_path);
+    _ = self.setField(-2, "path");
+  }
+}
+
 fn loadBaseConfig(self: *zlua.Lua) !void {
   const lua_path = "mez.path.base_config";
   if (!Bridge.getNestedField(self, @constCast(lua_path[0..]))) {
@@ -113,13 +141,15 @@ pub fn openLibs(self: *zlua.Lua) void {
   }
 }
 
-pub fn init(self: *Lua) !void {
+pub const Config = struct { str: ?[]const u8, enabled: bool, };
+pub fn init(self: *Lua, cfg: Config) !void {
   self.state = try zlua.Lua.init(gpa);
   errdefer self.state.deinit();
   self.state.openLibs();
 
   openLibs(self.state);
 
+  if (!cfg.enabled) try setBaseConfig(self.state, "");
   loadRuntimeDir(self.state) catch |err| if (err == error.LuaRuntime) {
     std.log.warn("{s}", .{try self.state.toString(-1)});
   };
@@ -128,9 +158,15 @@ pub fn init(self: *Lua) !void {
     std.log.warn("{s}", .{try self.state.toString(-1)});
   };
 
+  if (cfg.str) |path| {
+    defer gpa.free(path);
+    try setBaseConfig(self.state, path);
+  }
+  if (cfg.enabled) {
     loadConfigDir(self.state) catch |err| if (err == error.LuaRuntime) {
       std.log.warn("{s}", .{try self.state.toString(-1)});
     };
+  }
 
   std.log.debug("Loaded lua", .{});
 }

src/main.zig

@@ -1,4 +1,6 @@
 const std = @import("std");
+const config = @import("config");
+const clap = @import("clap");
 const wlr = @import("wlroots");
 
 const Server = @import("Server.zig");
@@ -10,14 +12,62 @@ pub var server: Server = undefined;
 pub var lua: Lua = undefined;
 pub var env_map: std.process.EnvMap = undefined;
 
-pub fn main() !void {
-  wlr.log.init(.err, null);
+const usage =
+    \\Usage: mez [options]
+    \\
+    \\Options:
+++ "\n" ++ args ++ "\n";
+const args =
+    \\   -u <path>            Use this config
+    \\   -c <command>         Runs this command at startup
+    \\   -v, --version        Print the version and exit
+    \\   -h, --help           Print this help and exit
+    \\
+    \\   --clean              "Factory defaults" (skip user config)
+;
 
+pub fn main() !void {
+  const params = comptime clap.parseParamsComptime(args);
+  var diag = clap.Diagnostic{};
+  const parsers = comptime .{
+    .path = clap.parsers.string,
+    .command = clap.parsers.string,
+  };
+  var res = clap.parse(clap.Help, &params, parsers, .{
+    .diagnostic = &diag,
+    .allocator = gpa,
+  }) catch |err| {
+    try diag.reportToFile(.stderr(), err);
+    return err;
+  };
+  defer res.deinit();
+
+  if (res.args.help == 1) {
+    try @constCast(&std.fs.File.stdout().writer(&[_]u8{}).interface).writeAll(usage);
+    std.process.exit(0);
+  }
+  if (res.args.version == 1) {
+    try @constCast(&std.fs.File.stdout().writer(&[_]u8{}).interface).writeAll(config.version);
+    std.process.exit(0);
+  }
+
+  var lua_config: Lua.Config = .{ .enabled = true, .str = null };
+  if (res.args.u != null and res.args.clean == 1) {
+    std.debug.panic("You cannot set both -u and --clean", .{});
+  } else if (res.args.u != null) {
+    // this is freed in lua/lua.zig
+    const path = try std.fs.cwd().realpathAlloc(gpa, res.args.u.?);
+    lua_config.str = path;
+  } else if (res.args.clean == 1) {
+    lua_config.enabled = false;
+  }
+
+  wlr.log.init(.err, null);
   std.log.info("Starting mezzaluna", .{});
 
   server.init();
   defer server.deinit();
-  try lua.init();
+  try lua.init(lua_config);
 
   var buf: [11]u8 = undefined;
   const socket = try server.wl_server.addSocketAuto(&buf);
@@ -25,8 +75,7 @@ pub fn main() !void {
   env_map = try std.process.getEnvMap(gpa);
   try env_map.put("WAYLAND_DISPLAY", socket);
 
-  if (std.os.argv.len >= 2) {
-    const cmd = std.mem.span(std.os.argv[1]);
+  if (res.args.c) |cmd| {
     var child = std.process.Child.init(&[_][]const u8{ "/bin/sh", "-c", cmd }, gpa);
     child.env_map = &env_map;
     try child.spawn();