river/common/flags.zig
Isaac Freund a5a505ecba
common: remove support for positional arguments
This is currently unused and I don't like the approach anymore
regardless. If/when we need positional arguments (probably when
implementing the upcoming river-control protocol in rivertile)
they should be handled separately from flags.

This commit also improves the CLI error reporting to always print the
usage string if invalid arguments were passed.
2021-07-24 18:29:48 +02:00

105 lines
3.5 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 cstr = std.cstr;
pub const Flag = struct {
name: [*:0]const u8,
kind: enum { boolean, arg },
};
pub fn ParseResult(comptime flags: []const Flag) type {
return struct {
const Self = @This();
const FlagData = struct {
name: [*:0]const u8,
value: union {
boolean: bool,
arg: ?[*:0]const u8,
},
};
/// Remaining args after the recognized flags
args: [][*:0]const u8,
/// Data obtained from parsed flags
flag_data: [flags.len]FlagData = blk: {
// Init all flags to false/null
var flag_data: [flags.len]FlagData = undefined;
inline for (flags) |flag, i| {
flag_data[i] = switch (flag.kind) {
.boolean => .{
.name = flag.name,
.value = .{ .boolean = false },
},
.arg => .{
.name = flag.name,
.value = .{ .arg = null },
},
};
}
break :blk flag_data;
},
pub fn boolFlag(self: Self, flag_name: [*:0]const u8) bool {
for (self.flag_data) |flag_data| {
if (cstr.cmp(flag_data.name, flag_name) == 0) return flag_data.value.boolean;
}
unreachable; // Invalid flag_name
}
pub fn argFlag(self: Self, flag_name: [*:0]const u8) ?[*:0]const u8 {
for (self.flag_data) |flag_data| {
if (cstr.cmp(flag_data.name, flag_name) == 0) return flag_data.value.arg;
}
unreachable; // Invalid flag_name
}
};
}
pub fn parse(args: [][*:0]const u8, comptime flags: []const Flag) !ParseResult(flags) {
var ret: ParseResult(flags) = .{ .args = undefined };
var arg_idx: usize = 0;
while (arg_idx < args.len) : (arg_idx += 1) {
var parsed_flag = false;
inline for (flags) |flag, flag_idx| {
if (cstr.cmp(flag.name, args[arg_idx]) == 0) {
switch (flag.kind) {
.boolean => ret.flag_data[flag_idx].value.boolean = true,
.arg => {
arg_idx += 1;
if (arg_idx == args.len) {
std.log.err("flag '" ++ flag.name ++
"' requires an argument but none was provided!", .{});
return error.MissingFlagArgument;
}
ret.flag_data[flag_idx].value.arg = args[arg_idx];
},
}
parsed_flag = true;
}
}
if (!parsed_flag) break;
}
ret.args = args[arg_idx..];
return ret;
}