add ShutdownHook

ts-core/build.gradle.kts

@@ -5,6 +5,7 @@ plugins {
 
 dependencies {
   api(project(":"))
+  api(group = "org.slf4j", name = "slf4j-api", version = "1.7.29")
   compileOnly(group = "com.google.code.gson", name = "gson", version = "2.8.6")
   compileOnly(group = "io.netty", name = "netty-all", version = "4.1.43.Final")
 }

ts-core/src/main/kotlin/cn/tursom/core/ShutdownHook.kt

@@ -0,0 +1,39 @@
+package cn.tursom.core
+
+import com.sun.org.slf4j.internal.LoggerFactory
+import java.util.concurrent.ConcurrentLinkedDeque
+import java.util.concurrent.atomic.AtomicInteger
+
+/**
+ * Runtime.getRuntime().addShutdownHook() 的高效版本
+ * 使用线程池免去了线程创建的开销
+ */
+@Suppress("unused")
+object ShutdownHook {
+  private val logger = LoggerFactory.getLogger(ShutdownHook::class.java)
+
+  private val shutdownHooks = ConcurrentLinkedDeque<() -> Unit>()
+  private val availableThreadCount = Runtime.getRuntime().availableProcessors() * 2
+  private val activeThreadCount = AtomicInteger()
+
+  fun addHook(hook: () -> Unit): Boolean {
+    if (activeThreadCount.incrementAndGet() <= availableThreadCount) {
+      addWorkThread()
+    }
+    return shutdownHooks.add(hook)
+  }
+
+  private fun addWorkThread() {
+    Runtime.getRuntime().addShutdownHook(Thread {
+      var hook = shutdownHooks.poll()
+      while (hook != null) {
+        try {
+          hook()
+        } catch (e: Throwable) {
+          //error("an exception caused on hook", e)
+        }
+        hook = shutdownHooks.poll()
+      }
+    })
+  }
+}