river/rivertile/args.zig
Isaac Freund 07fd1b86ca rivertile: support command line arguments
Add support for command line arguments to set default values for the
various options of rivertile, bringing us back to rough feature parity
with before the commit removing the river-options protocol.
2021-04-27 00:10:20 +02:00

127 lines
4.7 KiB
Zig

// This file is part of river, a dynamic tiling wayland compositor.
//
// Copyright 2021 The River Developers
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
const std = @import("std");
const mem = std.mem;
const cstr = std.cstr;
const root = @import("root");
pub const FlagDef = struct {
name: [*:0]const u8,
kind: enum { boolean, arg },
};
pub fn Args(comptime num_positionals: comptime_int, comptime flag_defs: []const FlagDef) type {
return struct {
const Self = @This();
positionals: [num_positionals][*:0]const u8,
flags: [flag_defs.len]struct {
name: [*:0]const u8,
value: union {
boolean: bool,
arg: ?[*:0]const u8,
},
},
pub fn parse(argv: [][*:0]const u8) Self {
var ret: Self = undefined;
// Init all flags in the flags array to false/null
inline for (flag_defs) |flag_def, flag_idx| {
switch (flag_def.kind) {
.boolean => ret.flags[flag_idx] = .{
.name = flag_def.name,
.value = .{ .boolean = false },
},
.arg => ret.flags[flag_idx] = .{
.name = flag_def.name,
.value = .{ .arg = null },
},
}
}
// Parse the argv in to the positionals and flags arrays
var arg_idx: usize = 0;
var positional_idx: usize = 0;
outer: while (arg_idx < argv.len) : (arg_idx += 1) {
var should_continue = false;
inline for (flag_defs) |flag_def, flag_idx| {
if (cstr.cmp(flag_def.name, argv[arg_idx]) == 0) {
switch (flag_def.kind) {
.boolean => ret.flags[flag_idx].value.boolean = true,
.arg => {
arg_idx += 1;
ret.flags[flag_idx].value.arg = if (arg_idx < argv.len)
argv[arg_idx]
else
root.fatal("flag '" ++ flag_def.name ++
"' requires an argument but none was provided!", .{});
},
}
// TODO: this variable exists as a workaround for the fact that
// using continue :outer here crashes the stage1 compiler.
should_continue = true;
}
}
if (should_continue) continue;
if (positional_idx == num_positionals) {
root.fatal(
"{} positional arguments expected but more were provided!",
.{num_positionals},
);
}
// This check should not be needed as this code is unreachable
// if num_positionals is 0. Howevere the stage1 zig compiler does
// not seem to be smart enough to realize this.
if (num_positionals > 0) {
ret.positionals[positional_idx] = argv[arg_idx];
} else {
unreachable;
}
positional_idx += 1;
}
if (positional_idx < num_positionals) {
root.fatal(
"{} positional arguments expected but only {} were provided!",
.{ num_positionals, positional_idx },
);
}
return ret;
}
pub fn boolFlag(self: Self, flag_name: [*:0]const u8) bool {
for (self.flags) |flag| {
if (cstr.cmp(flag.name, flag_name) == 0) return flag.value.boolean;
}
unreachable;
}
pub fn argFlag(self: Self, flag_name: [*:0]const u8) ?[*:0]const u8 {
for (self.flags) |flag| {
if (cstr.cmp(flag.name, flag_name) == 0) return flag.value.arg;
}
unreachable;
}
};
}