6bf607b759They should use gpa.destroy() instead of foo.destroy() because (most) of them have fields that may not be initialized by the first error, so the foo.destroy() could crash.
97 lines
3.6 KiB
Zig
97 lines
3.6 KiB
Zig
// SPDX-FileCopyrightText: © 2023 Isaac Freund
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// SPDX-License-Identifier: 0BSD
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//! Zero allocation argument parsing for unix-like systems.
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const std = @import("std");
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const mem = std.mem;
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pub const Flag = struct {
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name: [:0]const u8,
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kind: enum { boolean, arg },
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};
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pub fn Parser(comptime Arg: type, comptime flags: []const Flag) type {
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switch (Arg) {
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// TODO consider allowing []const u8
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[:0]const u8, [*:0]const u8 => {}, // ok
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else => @compileError("invalid argument type: " ++ @typeName(Arg)),
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}
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return struct {
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pub const Result = struct {
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/// Remaining args after the recognized flags
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args: []const Arg,
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/// Data obtained from parsed flags
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flags: Flags,
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pub const Flags = flags_type: {
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var fields: []const std.builtin.Type.StructField = &.{};
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for (flags) |flag| {
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const field: std.builtin.Type.StructField = switch (flag.kind) {
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.boolean => .{
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.name = flag.name,
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.type = bool,
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.default_value_ptr = &false,
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.is_comptime = false,
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.alignment = @alignOf(bool),
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},
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.arg => .{
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.name = flag.name,
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.type = ?[:0]const u8,
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.default_value_ptr = &@as(?[:0]const u8, null),
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.is_comptime = false,
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.alignment = @alignOf(?[:0]const u8),
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},
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};
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fields = fields ++ [_]std.builtin.Type.StructField{field};
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}
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break :flags_type @Type(.{ .@"struct" = .{
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.layout = .auto,
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.fields = fields,
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.decls = &.{},
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.is_tuple = false,
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} });
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};
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};
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pub fn parse(args: []const Arg) !Result {
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var result_flags: Result.Flags = .{};
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var i: usize = 0;
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outer: while (i < args.len) : (i += 1) {
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const arg = switch (Arg) {
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[*:0]const u8 => mem.sliceTo(args[i], 0),
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[:0]const u8 => args[i],
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else => unreachable,
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};
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inline for (flags) |flag| {
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if (mem.eql(u8, "-" ++ flag.name, arg)) {
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switch (flag.kind) {
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.boolean => @field(result_flags, flag.name) = true,
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.arg => {
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i += 1;
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if (i == args.len) {
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std.log.err("option '-" ++ flag.name ++
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"' requires an argument but none was provided!", .{});
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return error.MissingFlagArgument;
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}
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@field(result_flags, flag.name) = switch (Arg) {
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[*:0]const u8 => mem.sliceTo(args[i], 0),
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[:0]const u8 => args[i],
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else => unreachable,
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};
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},
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}
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continue :outer;
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}
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}
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break;
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}
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return Result{
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.args = args[i..],
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.flags = result_flags,
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};
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}
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};
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}
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