async.Run/Await/Race/All

x/async/async.go

@@ -0,0 +1,145 @@
+/*
+ * 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 async
+
+import (
+	"context"
+	"unsafe"
+	_ "unsafe"
+
+	"github.com/goplus/llgo/c/libuv"
+)
+
+type Void = [0]byte
+
+type Future[T any] func() T
+
+type IO[T any] func(e *AsyncContext) Future[T]
+
+type Chain[T any] func(callback func(T))
+
+func (f Future[T]) Do(callback func(T)) {
+	callback(f())
+}
+
+type AsyncContext struct {
+	context.Context
+	*Executor
+	Complete func()
+}
+
+func Async[T any](fn func(resolve func(T))) IO[T] {
+	return func(ctx *AsyncContext) Future[T] {
+		var result T
+		var done bool
+		fn(func(t T) {
+			result = t
+			done = true
+			ctx.Complete()
+		})
+		return func() T {
+			if !done {
+				panic("AsyncIO: Future accessed before completion")
+			}
+			return result
+		}
+	}
+}
+
+type bindAsync struct {
+	libuv.Async
+	cb func()
+}
+
+func BindIO[T any](call IO[T], callback func(T)) {
+	loop := Exec().L
+	a := &bindAsync{}
+	loop.Async(&a.Async, func(p *libuv.Async) {
+		(*bindAsync)(unsafe.Pointer(p)).cb()
+	})
+	ctx := &AsyncContext{
+		Context:  context.Background(),
+		Executor: Exec(),
+		Complete: func() {
+			a.Async.Send()
+		},
+	}
+	f := call(ctx)
+	a.cb = func() {
+		a.Async.Close(nil)
+		result := f()
+		callback(result)
+	}
+}
+
+// -----------------------------------------------------------------------------
+
+func Await[T1 any](call IO[T1]) (ret T1) {
+	ch := make(chan struct{})
+	f := call(&AsyncContext{
+		Context:  context.Background(),
+		Executor: Exec(),
+		Complete: func() {
+			close(ch)
+		},
+	})
+	<-ch
+	return f()
+}
+
+func Race[T1 any](calls ...IO[T1]) IO[T1] {
+	return Async(func(resolve func(T1)) {
+		done := false
+		for _, call := range calls {
+			var f Future[T1]
+			f = call(&AsyncContext{
+				Context:  context.Background(),
+				Executor: Exec(),
+				Complete: func() {
+					if done {
+						return
+					}
+					done = true
+					resolve(f())
+				},
+			})
+		}
+	})
+}
+
+func All[T1 any](calls ...IO[T1]) IO[[]T1] {
+	return Async(func(resolve func([]T1)) {
+		n := len(calls)
+		results := make([]T1, n)
+		done := 0
+		for i, call := range calls {
+			i := i
+			var f Future[T1]
+			f = call(&AsyncContext{
+				Context:  context.Background(),
+				Executor: Exec(),
+				Complete: func() {
+					results[i] = f()
+					done++
+					if done == n {
+						resolve(results)
+					}
+				},
+			})
+		}
+	})
+}