首次提交：初始化项目代码

write_barrier_simulation.go

@@ -0,0 +1,81 @@
+package main
+
+import (
+	"fmt"
+	"sync/atomic"
+)
+
+const (
+	White, Grey, Black = 0, 1, 2
+)
+
+type SimObject struct {
+	ID    string
+	Color int32
+	Ref   *SimObject
+}
+
+func (o *SimObject) SetColor(c int32) { atomic.StoreInt32(&o.Color, c) }
+func (o *SimObject) GetColor() int32  { return atomic.LoadInt32(&o.Color) }
+
+// 插入屏障：黑色→白色时标灰新对象（概念模拟）
+func InsertionBarrier(parent, child *SimObject) bool {
+	if parent.GetColor() == Black && child.GetColor() == White {
+		child.SetColor(Grey)
+		return true
+	}
+	return false
+}
+
+// 删除屏障：无条件标灰旧引用（概念模拟）
+func DeletionBarrier(oldRef *SimObject) bool {
+	if oldRef != nil && oldRef.GetColor() != Black {
+		oldRef.SetColor(Grey)
+		return true
+	}
+	return false
+}
+
+func colorName(c int32) string {
+	switch c {
+	case White:
+		return "白"
+	case Grey:
+		return "灰"
+	case Black:
+		return "黑"
+	}
+	return "未知"
+}
+
+func main() {
+	fmt.Println("=== 场景1：无屏障 → 漏标风险 ===")
+	A := &SimObject{ID: "A", Color: Black}
+	B := &SimObject{ID: "B", Color: White}
+	A.Ref = B
+	C := &SimObject{ID: "C", Color: White}
+	A.Ref = C
+	fmt.Printf("⚠️ B 状态: %s (孤立白色对象，应被回收)\n", colorName(B.GetColor()))
+
+	fmt.Println("\n=== 场景2：插入屏障保护 ===")
+	A.SetColor(Black)
+	B.SetColor(White)
+	A.Ref = B
+	D := &SimObject{ID: "D", Color: White}
+	if InsertionBarrier(A, D) {
+		fmt.Printf("🛡️ [插入] A(黑)→D(白) → D 标灰\n")
+	}
+	A.Ref = D
+	fmt.Printf("✅ D 状态: %s (被屏障保护)\n", colorName(D.GetColor()))
+
+	fmt.Println("\n=== 场景3：删除屏障保护 ===")
+	E := &SimObject{ID: "E", Color: Black}
+	F := &SimObject{ID: "F", Color: White}
+	E.Ref = F
+	G := &SimObject{ID: "G", Color: White}
+	if DeletionBarrier(E.Ref) {
+		fmt.Printf("🛡️ [删除] 旧引用 F(白) → F 标灰\n")
+	}
+	E.Ref = G
+	fmt.Printf("✅ F 状态: %s (被屏障重新标灰)\n", colorName(F.GetColor()))
+}