libuv: Timers

src/libuv/Loop.zig

@@ -30,6 +30,13 @@ pub fn deinit(self: *Loop, alloc: Allocator) void {
     self.* = undefined;
 }
 
+/// Returns true if the loop is still alive.
+pub fn alive(self: Loop) !bool {
+    const res = c.uv_loop_alive(self.loop);
+    try errors.convertError(res);
+    return res > 0;
+}
+
 /// This function runs the event loop. See RunMode for mode documentation.
 ///
 /// This is not reentrant. It must not be called from a callback.

src/libuv/Timer.zig

@@ -0,0 +1,54 @@
+//! Timer handles are used to schedule callbacks to be called in the future.
+const Timer = @This();
+
+const std = @import("std");
+const Allocator = std.mem.Allocator;
+const testing = std.testing;
+const c = @import("c.zig");
+const errors = @import("error.zig");
+const Loop = @import("Loop.zig");
+const Handle = @import("handle.zig").Handle;
+
+handle: *c.uv_timer_t,
+
+pub usingnamespace Handle(Timer);
+
+pub fn init(alloc: Allocator, loop: Loop) !Timer {
+    var timer = try alloc.create(c.uv_timer_t);
+    errdefer alloc.destroy(timer);
+    try errors.convertError(c.uv_timer_init(loop.loop, timer));
+    return Timer{ .handle = timer };
+}
+
+pub fn deinit(self: *Timer, alloc: Allocator) void {
+    alloc.destroy(self.handle);
+    self.* = undefined;
+}
+
+test "Timer" {
+    var loop = try Loop.init(testing.allocator);
+    defer loop.deinit(testing.allocator);
+    var timer = try init(testing.allocator, loop);
+    defer timer.deinit(testing.allocator);
+    timer.close(null);
+    _ = try loop.run(.default);
+}
+
+test "Timer: close callback" {
+    var loop = try Loop.init(testing.allocator);
+    defer loop.deinit(testing.allocator);
+    var timer = try init(testing.allocator, loop);
+    defer timer.deinit(testing.allocator);
+
+    var data: u8 = 42;
+    timer.setData(&data);
+    timer.close((struct {
+        fn callback(v: *Timer) void {
+            var dataPtr = v.getData(u8).?;
+            dataPtr.* = 24;
+        }
+    }).callback);
+    _ = try loop.run(.default);
+
+    try testing.expectEqual(@as(u8, 24), data);
+}

src/libuv/handle.zig

@@ -0,0 +1,60 @@
+const c = @import("c.zig");
+
+/// Returns a struct that has all the shared handle functions for the
+/// given handle type T. The type T must have a field named "handle".
+/// This is expected to be used with usingnamespace to add the shared
+/// handler functions to other handle types.
+pub fn Handle(comptime T: type) type {
+    // 1. T should be a struct
+    // 2. First field should be the handle pointer
+    const tInfo = @typeInfo(T).Struct;
+    const HandleType = tInfo.fields[0].field_type;
+
+    return struct {
+        // Request handle to be closed. close_cb will be called asynchronously
+        // after this call. This MUST be called on each handle before memory
+        // is released. Moreover, the memory can only be released in close_cb
+        // or after it has returned.
+        //
+        // Handles that wrap file descriptors are closed immediately but
+        // close_cb will still be deferred to the next iteration of the event
+        // loop. It gives you a chance to free up any resources associated with
+        // the handle.
+        //
+        // In-progress requests, like uv_connect_t or uv_write_t, are cancelled
+        // and have their callbacks called asynchronously with status=UV_ECANCELED.
+        pub fn close(self: *T, comptime cb: ?fn (*T) void) void {
+            const cbParam = if (cb) |f|
+                (struct {
+                    pub fn callback(handle: [*c]c.uv_handle_t) callconv(.C) void {
+                        // We get the raw handle, so we need to reconstruct
+                        // the T. This is mutable because a lot of the libuv APIs
+                        // are non-const but modifying it makes no sense.
+                        var param: T = .{ .handle = @ptrCast(HandleType, handle) };
+
+                        @call(.{ .modifier = .always_inline }, f, .{&param});
+                    }
+                }).callback
+            else
+                null;
+
+            c.uv_close(@ptrCast(*c.uv_handle_t, self.handle), cbParam);
+        }
+
+        /// Sets handle->data to data.
+        pub fn setData(self: *T, pointer: ?*anyopaque) void {
+            c.uv_handle_set_data(
+                @ptrCast(*c.uv_handle_t, self.handle),
+                pointer,
+            );
+        }
+
+        /// Returns handle->data.
+        pub fn getData(self: *T, comptime DT: type) ?*DT {
+            return if (c.uv_handle_get_data(@ptrCast(*c.uv_handle_t, self.handle))) |ptr|
+                @ptrCast(?*DT, @alignCast(@alignOf(DT), ptr))
+            else
+                null;
+        }
+    };
+}

src/libuv/main.zig

@@ -1,10 +1,12 @@
 const Loop = @import("Loop.zig");
+const Timer = @import("Timer.zig");
 const Sem = @import("Sem.zig");
 const Thread = @import("Thread.zig");
 const Error = @import("error.zig").Error;
 
 test {
     _ = Loop;
+    _ = Timer;
     _ = Sem;
     _ = Thread;
     _ = Error;