Catch and forward event broadcasting to EventDispatcher

mirai-core-api/src/commonMain/kotlin/IMirai.kt

@@ -19,6 +19,9 @@ import io.ktor.client.engine.okhttp.*
 import net.mamoe.kjbb.JvmBlockingBridge
 import net.mamoe.mirai.contact.*
 import net.mamoe.mirai.data.UserProfile
+import net.mamoe.mirai.event.Event
+import net.mamoe.mirai.event.broadcast
+import net.mamoe.mirai.event.broadcastImpl
 import net.mamoe.mirai.event.events.BotInvitedJoinGroupRequestEvent
 import net.mamoe.mirai.event.events.MemberJoinRequestEvent
 import net.mamoe.mirai.event.events.NewFriendRequestEvent
@@ -299,6 +302,13 @@ public interface IMirai : LowLevelApiAccessor {
      * @param event 邀请入群的事件对象
      */
     public suspend fun ignoreInvitedJoinGroupRequest(event: BotInvitedJoinGroupRequestEvent)
+
+    /**
+     * 广播一个事件. 由 [Event.broadcast] 调用.
+     */
+    public suspend fun broadcastEvent(event: Event) {
+        event.broadcastImpl()
+    }
 }
 
 /**

mirai-core-api/src/commonMain/kotlin/event/Event.kt

@@ -14,6 +14,7 @@ package net.mamoe.mirai.event
 import kotlinx.coroutines.runBlocking
 import kotlinx.coroutines.sync.Mutex
 import kotlinx.coroutines.sync.withLock
+import net.mamoe.mirai.Mirai
 import net.mamoe.mirai.event.events.BotEvent
 import net.mamoe.mirai.event.events.MessageEvent
 import net.mamoe.mirai.internal.event.callAndRemoveIfRequired
@@ -144,7 +145,11 @@ public interface CancellableEvent : Event {
  * @see __broadcastJava Java 使用
  */
 @JvmSynthetic
-public suspend fun <E : Event> E.broadcast(): E {
+public suspend fun <E : Event> E.broadcast(): E = apply { Mirai.broadcastEvent(this) }
+
+
+@JvmName("broadcastImpl") // avoid mangling
+internal suspend fun <E : Event> E.broadcastImpl(): E {
     val event = this
     check(event is AbstractEvent) {
         "Events must extend AbstractEvent"

mirai-core/src/commonMain/kotlin/MiraiImpl.kt

@@ -15,22 +15,23 @@ import io.ktor.client.features.*
 import io.ktor.client.request.*
 import io.ktor.client.request.forms.*
 import kotlinx.coroutines.SupervisorJob
+import kotlinx.coroutines.currentCoroutineContext
 import kotlinx.io.core.discardExact
 import kotlinx.io.core.readBytes
 import kotlinx.serialization.json.*
 import net.mamoe.mirai.*
 import net.mamoe.mirai.contact.*
 import net.mamoe.mirai.data.*
+import net.mamoe.mirai.event.Event
 import net.mamoe.mirai.event.broadcast
-import net.mamoe.mirai.event.events.BotInvitedJoinGroupRequestEvent
-import net.mamoe.mirai.event.events.FriendAddEvent
-import net.mamoe.mirai.event.events.MemberJoinRequestEvent
-import net.mamoe.mirai.event.events.NewFriendRequestEvent
+import net.mamoe.mirai.event.events.*
 import net.mamoe.mirai.internal.contact.*
 import net.mamoe.mirai.internal.contact.info.FriendInfoImpl
 import net.mamoe.mirai.internal.contact.info.MemberInfoImpl
 import net.mamoe.mirai.internal.message.*
 import net.mamoe.mirai.internal.message.DeepMessageRefiner.refineDeep
+import net.mamoe.mirai.internal.network.components.EventDispatcher
+import net.mamoe.mirai.internal.network.components.EventDispatcherScopeFlag
 import net.mamoe.mirai.internal.network.highway.*
 import net.mamoe.mirai.internal.network.protocol.data.jce.SvcDevLoginInfo
 import net.mamoe.mirai.internal.network.protocol.data.proto.ImMsgBody
@@ -284,6 +285,20 @@ internal open class MiraiImpl : IMirai, LowLevelApiAccessor {
     override suspend fun ignoreInvitedJoinGroupRequest(event: BotInvitedJoinGroupRequestEvent) =
         solveInvitedJoinGroupRequest(event, accept = false)
 
+    override suspend fun broadcastEvent(event: Event) {
+        if (currentCoroutineContext()[EventDispatcherScopeFlag] != null) {
+            // called by [EventDispatcher]
+            return super.broadcastEvent(event)
+        }
+        if (event is BotEvent) {
+            val bot = event.bot
+            if (bot is QQAndroidBot) {
+                bot.components[EventDispatcher].broadcast(event)
+            }
+        } else {
+            super.broadcastEvent(event)
+        }
+    }
 
     private suspend fun solveInvitedJoinGroupRequest(event: BotInvitedJoinGroupRequestEvent, accept: Boolean) {
         @Suppress("INVISIBLE_REFERENCE", "INVISIBLE_MEMBER")

mirai-core/src/commonMain/kotlin/network/components/EventDispatcher.kt

@@ -19,8 +19,18 @@ import net.mamoe.mirai.utils.childScope
 import kotlin.coroutines.CoroutineContext
 import kotlin.coroutines.EmptyCoroutineContext
 
+/**
+ * All events will be caught and forwarded to [EventDispatcher]. Invocation of [Event.broadcast] and [EventDispatcher.broadcast] are effectively equal.
+ */
 internal interface EventDispatcher {
+    /**
+     * Implementor must call `event.broadcast()` within a coroutine with [EventDispatcherScopeFlag]
+     */
     suspend fun broadcast(event: Event)
+
+    /**
+     * Implementor must call `event.broadcast()` within a coroutine with [EventDispatcherScopeFlag]
+     */
     fun broadcastAsync(event: Event, additionalContext: CoroutineContext = EmptyCoroutineContext): EventBroadcastJob
 
     /**
@@ -31,6 +41,10 @@ internal interface EventDispatcher {
     companion object : ComponentKey<EventDispatcher>
 }
 
+internal object EventDispatcherScopeFlag : CoroutineContext.Element, CoroutineContext.Key<EventDispatcherScopeFlag> {
+    override val key: CoroutineContext.Key<*> get() = this
+}
+
 @JvmInline
 internal value class EventBroadcastJob(
     private val job: Job
@@ -53,7 +67,9 @@ internal class EventDispatcherImpl(
 
     override suspend fun broadcast(event: Event) {
         try {
-            event.broadcast()
+            withContext(EventDispatcherScopeFlag) {
+                event.broadcast()
+            }
         } catch (e: Exception) {
             if (logger.isEnabled) {
                 val msg = optimizeEventToString(event)
@@ -63,7 +79,10 @@ internal class EventDispatcherImpl(
     }
 
     override fun broadcastAsync(event: Event, additionalContext: CoroutineContext): EventBroadcastJob {
-        val job = launch(additionalContext, start = CoroutineStart.UNDISPATCHED) { broadcast(event) }
+        val job = launch(
+            additionalContext + EventDispatcherScopeFlag,
+            start = CoroutineStart.UNDISPATCHED
+        ) { broadcast(event) }
         // UNDISPATCHED: starts the coroutine NOW in the current thread until its first suspension point,
         // so that after `broadcastAsync` the job is always already started and `joinBroadcast` will work normally.
         return EventBroadcastJob(job)