47 lines
1.1 KiB
Zig
47 lines
1.1 KiB
Zig
// SPDX-License-Identifier: MIT
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// Copyright (c) 2015-2020 Zig Contributors
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// This file is part of [zig](https://ziglang.org/), which is MIT licensed.
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// The MIT license requires this copyright notice to be included in all copies
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// and substantial portions of the software.
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const std = @import("std");
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const WaitGroup = @This();
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const Event = @import("Event.zig");
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lock: std.Mutex = .{},
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counter: usize = 0,
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event: ?*Event = null,
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pub fn start(self: *WaitGroup) void {
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const held = self.lock.acquire();
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defer held.release();
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self.counter += 1;
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}
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pub fn stop(self: *WaitGroup) void {
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var event: ?*Event = null;
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defer if (event) |waiter|
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waiter.set();
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const held = self.lock.acquire();
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defer held.release();
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self.counter -= 1;
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if (self.counter == 0)
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std.mem.swap(?*Event, &self.event, &event);
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}
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pub fn wait(self: *WaitGroup) void {
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var event = Event{};
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var has_event = false;
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defer if (has_event)
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event.wait();
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const held = self.lock.acquire();
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defer held.release();
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has_event = self.counter != 0;
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if (has_event)
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self.event = &event;
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}
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