76 lines
2.0 KiB
Zig
76 lines
2.0 KiB
Zig
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const builtin = @import("builtin");
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const std = @import("std");
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pub fn RefCounting(comptime Payload: type, comptime finalize: fn (*Payload) void) type {
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const AtomicCount = std.atomic.Value(usize);
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return opaque {
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const Layout = struct {
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ref_count: AtomicCount,
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payload: Payload,
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fn get(self: *Self) *Layout {
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return @ptrCast(@alignCast(self));
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}
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fn get_const(self: *const Self) *const Layout {
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return @ptrCast(@alignCast(self));
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}
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};
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const Self = @This();
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pub fn acquire(self: *Self) *const Payload {
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const layout = Layout.get(self);
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const ref_count = layout.ref_count.fetchAdd(1, .monotonic);
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std.debug.assert(ref_count != 0);
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return &layout.payload;
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}
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pub fn create(payload: Payload) std.mem.Allocator.Error!*Self {
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const allocation = try allocator.create(Layout);
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errdefer {
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allocator.destroy(allocation);
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}
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allocation.* = .{
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.ref_count = AtomicCount.init(1),
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.payload = payload,
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};
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return @ptrCast(allocation);
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}
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pub fn release(self: *Self) void {
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const layout = Layout.get(self);
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const ref_count = layout.ref_count.fetchSub(1, .monotonic);
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std.debug.assert(ref_count != 0);
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if (ref_count == 1) {
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finalize(&layout.payload);
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allocator.destroy(layout);
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}
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}
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pub fn weak(self: *const Self) *const Payload {
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return &Layout.get_const(self).payload;
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}
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};
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}
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pub const allocator = switch (builtin.mode) {
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.ReleaseFast => std.heap.smp_allocator,
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else => gpa.allocator(),
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};
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var gpa = std.heap.GeneralPurposeAllocator(.{ .thread_safe = true }){};
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pub fn traceLeaks() void {
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_ = gpa.detectLeaks();
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}
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