109 lines
3.7 KiB
Zig
109 lines
3.7 KiB
Zig
const std = @import("std.zig");
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const builtin = @import("builtin");
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const AtomicOrder = builtin.AtomicOrder;
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const AtomicRmwOp = builtin.AtomicRmwOp;
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const assert = std.debug.assert;
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const expect = std.testing.expect;
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const windows = std.os.windows;
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/// Lock may be held only once. If the same thread
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/// tries to acquire the same mutex twice, it deadlocks.
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/// This type is intended to be initialized statically. If you don't
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/// require static initialization, use std.Mutex.
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/// On Windows, this mutex allocates resources when it is
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/// first used, and the resources cannot be freed.
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/// On Linux, this is an alias of std.Mutex.
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pub const StaticallyInitializedMutex = switch (builtin.os) {
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builtin.Os.linux => std.Mutex,
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builtin.Os.windows => struct {
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lock: windows.CRITICAL_SECTION,
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init_once: windows.RTL_RUN_ONCE,
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pub const Held = struct {
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mutex: *StaticallyInitializedMutex,
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pub fn release(self: Held) void {
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windows.LeaveCriticalSection(&self.mutex.lock);
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}
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};
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pub fn init() StaticallyInitializedMutex {
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return StaticallyInitializedMutex{
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.lock = undefined,
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.init_once = windows.INIT_ONCE_STATIC_INIT,
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};
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}
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extern fn initCriticalSection(
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InitOnce: *windows.RTL_RUN_ONCE,
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Parameter: ?*c_void,
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Context: ?*c_void,
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) windows.BOOL {
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const lock = @ptrCast(*windows.CRITICAL_SECTION, @alignCast(@alignOf(windows.CRITICAL_SECTION), Parameter));
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windows.InitializeCriticalSection(lock);
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return windows.TRUE;
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}
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/// TODO: once https://github.com/ziglang/zig/issues/287 is solved and std.Mutex has a better
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/// implementation of a runtime initialized mutex, remove this function.
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pub fn deinit(self: *StaticallyInitializedMutex) void {
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assert(windows.InitOnceExecuteOnce(&self.init_once, initCriticalSection, &self.lock, null) != 0);
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windows.DeleteCriticalSection(&self.lock);
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}
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pub fn acquire(self: *StaticallyInitializedMutex) Held {
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assert(windows.InitOnceExecuteOnce(&self.init_once, initCriticalSection, &self.lock, null) != 0);
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windows.EnterCriticalSection(&self.lock);
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return Held{ .mutex = self };
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}
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},
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else => std.Mutex,
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};
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test "std.StaticallyInitializedMutex" {
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const TestContext = struct {
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data: i128,
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const TestContext = @This();
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const incr_count = 10000;
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var mutex = StaticallyInitializedMutex.init();
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fn worker(ctx: *TestContext) void {
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var i: usize = 0;
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while (i != TestContext.incr_count) : (i += 1) {
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const held = mutex.acquire();
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defer held.release();
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ctx.data += 1;
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}
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}
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};
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var direct_allocator = std.heap.DirectAllocator.init();
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defer direct_allocator.deinit();
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var plenty_of_memory = try direct_allocator.allocator.alloc(u8, 300 * 1024);
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defer direct_allocator.allocator.free(plenty_of_memory);
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var fixed_buffer_allocator = std.heap.ThreadSafeFixedBufferAllocator.init(plenty_of_memory);
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var a = &fixed_buffer_allocator.allocator;
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var context = TestContext{ .data = 0 };
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if (builtin.single_threaded) {
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TestContext.worker(&context);
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expect(context.data == TestContext.incr_count);
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} else {
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const thread_count = 10;
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var threads: [thread_count]*std.os.Thread = undefined;
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for (threads) |*t| {
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t.* = try std.os.spawnThread(&context, TestContext.worker);
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}
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for (threads) |t|
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t.wait();
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expect(context.data == thread_count * TestContext.incr_count);
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}
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}
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