erm/vendor/github.com/hajimehoshi/ebiten/v2/internal/thread/thread.go

87 lines
2.0 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 (
"errors"
)
// Thread defines threading behavior in Ebiten.
type Thread interface {
Call(func() error) error
Loop()
}
// OSThread represents an OS thread.
type OSThread struct {
funcs chan func() error
results chan error
}
// NewOSThread creates a new thread.
//
// It is assumed that the OS thread is fixed by runtime.LockOSThread when NewOSThread is called.
func NewOSThread() *OSThread {
return &OSThread{
funcs: make(chan func() error),
results: make(chan error),
}
}
// BreakLoop represents an termination of the loop.
var BreakLoop = errors.New("break loop")
// Loop starts the thread loop until a posted function returns BreakLoop.
//
// Loop must be called on the thread.
func (t *OSThread) Loop() {
for f := range t.funcs {
err := f()
if err == BreakLoop {
t.results <- nil
return
}
t.results <- err
}
}
// Call calls f on the thread.
//
// Do not call this from the same thread. This would block forever.
//
// If f returns BreakLoop, Loop returns.
//
// Call blocks if Loop is not called.
func (t *OSThread) Call(f func() error) error {
t.funcs <- f
return <-t.results
}
// 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() {}
// Call executes the func immediately
func (t *NoopThread) Call(f func() error) error {
return f()
}