ebiten/internal/thread/thread.go

88 lines
1.9 KiB
Go

// Copyright 2018 The Ebiten Authors
//
// 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 thread
import (
"context"
)
// Thread defines threading behavior in Ebitengine.
type Thread interface {
Call(func())
Loop(context.Context) error
}
// OSThread represents an OS thread.
type OSThread struct {
funcs chan func()
done chan struct{}
}
// NewOSThread creates a new thread.
func NewOSThread() *OSThread {
return &OSThread{
funcs: make(chan func()),
done: make(chan struct{}),
}
}
// Loop starts the thread loop until Stop is called.
//
// It is assumed that an OS thread is fixed by runtime.LockOSThread when Loop is called.
//
// Loop must be called on the thread.
func (t *OSThread) Loop(ctx context.Context) error {
for {
select {
case fn := <-t.funcs:
func() {
defer func() {
t.done <- struct{}{}
}()
fn()
}()
case <-ctx.Done():
return ctx.Err()
}
}
}
// Call calls f on the thread.
//
// Do not call this from the same thread. This would block forever.
//
// Call blocks if Loop is not called.
func (t *OSThread) Call(f func()) {
t.funcs <- f
<-t.done
}
// NoopThread is used to disable threading.
type NoopThread struct{}
// NewNoopThread creates a new thread that does no threading.
func NewNoopThread() *NoopThread {
return &NoopThread{}
}
// Loop does nothing
func (t *NoopThread) Loop(ctx context.Context) error {
return nil
}
// Call executes the func immediately
func (t *NoopThread) Call(f func()) { f() }