add MainDispatcher to replace Dispatchers.Main

utils/src/main/kotlin/cn/tursom/utils/coroutine/MainDispatcher.kt

@@ -0,0 +1,36 @@
+package cn.tursom.utils.coroutine
+
+import kotlinx.coroutines.MainCoroutineDispatcher
+import kotlinx.coroutines.asCoroutineDispatcher
+import java.io.Closeable
+import java.lang.reflect.Field
+import java.lang.reflect.Modifier
+import java.util.concurrent.Executors
+import kotlin.concurrent.thread
+import kotlin.coroutines.CoroutineContext
+
+object MainDispatcher : MainCoroutineDispatcher(), Closeable {
+  private val dispatcher = Executors.newSingleThreadExecutor {
+    thread(start = false, block = it::run, name = "mainDispatcher", isDaemon = false)
+  }.asCoroutineDispatcher()
+
+  fun init() {
+    val mainDispatcherLoader = Class.forName("kotlinx.coroutines.internal.MainDispatcherLoader")
+    val dispatcher = mainDispatcherLoader.getDeclaredField("dispatcher")
+    dispatcher.isAccessible = true
+    val mf: Field = Field::class.java.getDeclaredField("modifiers")
+    mf.isAccessible = true
+    mf.setInt(dispatcher, dispatcher.modifiers and Modifier.FINAL.inv())
+    dispatcher.set(null, this)
+  }
+
+  override val immediate: MainCoroutineDispatcher get() = this
+
+  override fun dispatch(context: CoroutineContext, block: Runnable) {
+    dispatcher.dispatch(context, block)
+  }
+
+  override fun close() {
+    dispatcher.close()
+  }
+}

utils/src/test/kotlin/cn/tursom/utils/coroutine/CoroutineLocalTest.kt

@@ -1,8 +1,11 @@
 package cn.tursom.utils.coroutine
 
+import cn.tursom.core.cast
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.GlobalScope
+import kotlinx.coroutines.launch
+import java.io.Closeable
 import kotlin.coroutines.coroutineContext
-import kotlin.coroutines.resume
-import kotlin.coroutines.suspendCoroutine
 
 val testCoroutineLocal = CoroutineLocal<Int>()
 
@@ -16,13 +19,11 @@ suspend fun testInlineCustomContext() {
   println("===================")
 }
 
-suspend fun main() {
-  println(getContinuation())
-  suspendCoroutine<Int> { cont ->
-    println(cont)
-    cont.resume(0)
+fun main() {
+  MainDispatcher.init()
+  GlobalScope.launch(Dispatchers.Main) {
+    println(Thread.currentThread().name)
+  }.invokeOnCompletion {
+    Dispatchers.Main.cast<Closeable>().close()
   }
-  testCustomContext()
-  println(testCoroutineLocal.get())
-  testInlineCustomContext()
 }