libuv: add async

c/libuv/_demo/async/async.go

@@ -0,0 +1,41 @@
+package main
+
+import (
+	"github.com/goplus/llgo/c"
+	"github.com/goplus/llgo/c/libuv"
+)
+
+func ensure(b bool, msg string) {
+	if !b {
+		panic(msg)
+	}
+}
+
+func main() {
+	loop := libuv.LoopNew()
+	defer loop.Close()
+
+	a := &libuv.Async{}
+	r := loop.Async(a, func(a *libuv.Async) {
+		println("async callback")
+		a.Close(nil) // or loop.Stop()
+	})
+	ensure(r == 0, "Async failed")
+
+	go func() {
+		println("begin async task")
+		c.Usleep(100 * 1000)
+		println("send async event")
+		ensure(a.Send() == 0, "Send failed")
+	}()
+
+	loop.Run(libuv.RUN_DEFAULT)
+	println("done")
+}
+
+/*Expected Output:
+begin async task
+send async event
+async callback
+done
+*/

c/libuv/async.go

@@ -0,0 +1,50 @@
+/*
+ * Copyright (c) 2024 The GoPlus Authors (goplus.org). All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package libuv
+
+import (
+	_ "unsafe"
+
+	"github.com/goplus/llgo/c"
+)
+
+// struct uv_async_t
+type Async struct {
+	Handle
+	// On macOS arm64, sizeof uv_async_t is 128 bytes.
+	// Handle is 92 bytes, so we need 36 bytes to fill the gap.
+	// Maybe reserve more for future use.
+	Unused [36]byte
+}
+
+// typedef void (*uv_async_cb)(uv_async_t* handle);
+// llgo:type C
+type AsyncCb func(*Async)
+
+// int uv_async_init(uv_loop_t*, uv_async_t* async, uv_async_cb async_cb);
+//
+// llgo:link (*Loop).Async C.uv_async_init
+func (loop *Loop) Async(a *Async, cb AsyncCb) c.Int {
+	return 0
+}
+
+// int uv_async_send(uv_async_t* async);
+//
+// llgo:link (*Async).Send C.uv_async_send
+func (a *Async) Send() c.Int {
+	return 0
+}