dontgc.go

// Copyright 2021 Google LLC
//
// 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 dontgc

import (
	"runtime"

	"github.com/divVerent/aaaaxy/internal/log"
)

type State []uintptr

type GCChecker interface {
	CheckGC() State
}

func SetUp(p GCChecker) State {
	stackTrace := make([]uintptr, 64)
	stackLen := runtime.Callers(1, stackTrace)
	stackTrace = stackTrace[:stackLen]
	runtime.SetFinalizer(p, finalize)
	return State(stackTrace)
}

func finalize(g GCChecker) {
	stackTrace := g.CheckGC()
	if stackTrace == nil {
		return
	}
	log.Errorf("BUG: GC forbidden for object that went out of scope; created here:")
	stackFrames := runtime.CallersFrames([]uintptr(stackTrace))
	for {
		frame, more := stackFrames.Next()
		log.Errorf("%v @ %v:%v", frame.Function, frame.File, frame.Line)
		if !more {
			break
		}
	}
}