Add concurrency control to message listeners, close #152

mirai-core/src/commonMain/kotlin/net.mamoe.mirai/event/subscribeMessages.kt

@@ -19,6 +19,7 @@ import net.mamoe.mirai.Bot
 import net.mamoe.mirai.contact.isAdministrator
 import net.mamoe.mirai.contact.isOperator
 import net.mamoe.mirai.contact.isOwner
+import net.mamoe.mirai.event.events.BotEvent
 import net.mamoe.mirai.message.FriendMessage
 import net.mamoe.mirai.message.GroupMessage
 import net.mamoe.mirai.message.MessagePacket
@@ -37,6 +38,7 @@ import kotlin.coroutines.EmptyCoroutineContext
 @OptIn(ExperimentalContracts::class)
 fun <R> CoroutineScope.subscribeMessages(
     coroutineContext: CoroutineContext = EmptyCoroutineContext,
+    concurrencyKind: Listener.ConcurrencyKind = Listener.ConcurrencyKind.CONCURRENT,
     listeners: MessageSubscribersBuilder<MessagePacket<*, *>>.() -> R
 ): R {
     // contract 可帮助 IDE 进行类型推断. 无实际代码作用.
@@ -47,7 +49,7 @@ fun <R> CoroutineScope.subscribeMessages(
     return MessageSubscribersBuilder { messageListener: MessageListener<MessagePacket<*, *>> ->
         // subscribeAlways 即注册一个监听器. 这个监听器收到消息后就传递给 [messageListener]
         // messageListener 即为 DSL 里 `contains(...) { }`, `startsWith(...) { }` 的代码块.
-        subscribeAlways(coroutineContext) {
+        subscribeAlways(coroutineContext, concurrencyKind) {
             messageListener.invoke(this, this.message.toString())
             // this.message.toString() 即为 messageListener 中 it 接收到的值
         }
@@ -62,13 +64,14 @@ fun <R> CoroutineScope.subscribeMessages(
 @OptIn(ExperimentalContracts::class)
 fun <R> CoroutineScope.subscribeGroupMessages(
     coroutineContext: CoroutineContext = EmptyCoroutineContext,
+    concurrencyKind: Listener.ConcurrencyKind = Listener.ConcurrencyKind.CONCURRENT,
     listeners: MessageSubscribersBuilder<GroupMessage>.() -> R
 ): R {
     contract {
         callsInPlace(listeners, InvocationKind.EXACTLY_ONCE)
     }
     return MessageSubscribersBuilder<GroupMessage> { listener ->
-        subscribeAlways(coroutineContext) {
+        subscribeAlways(coroutineContext, concurrencyKind) {
             listener(this, this.message.toString())
         }
     }.run(listeners)
@@ -82,13 +85,14 @@ fun <R> CoroutineScope.subscribeGroupMessages(
 @OptIn(ExperimentalContracts::class)
 fun <R> CoroutineScope.subscribeFriendMessages(
     coroutineContext: CoroutineContext = EmptyCoroutineContext,
+    concurrencyKind: Listener.ConcurrencyKind = Listener.ConcurrencyKind.CONCURRENT,
     listeners: MessageSubscribersBuilder<FriendMessage>.() -> R
 ): R {
     contract {
         callsInPlace(listeners, InvocationKind.EXACTLY_ONCE)
     }
     return MessageSubscribersBuilder<FriendMessage> { listener ->
-        subscribeAlways(coroutineContext) {
+        subscribeAlways(coroutineContext, concurrencyKind) {
             listener(this, this.message.toString())
         }
     }.run(listeners)
@@ -102,13 +106,14 @@ fun <R> CoroutineScope.subscribeFriendMessages(
 @OptIn(ExperimentalContracts::class)
 fun <R> Bot.subscribeMessages(
     coroutineContext: CoroutineContext = EmptyCoroutineContext,
+    concurrencyKind: Listener.ConcurrencyKind = Listener.ConcurrencyKind.CONCURRENT,
     listeners: MessageSubscribersBuilder<MessagePacket<*, *>>.() -> R
 ): R {
     contract {
         callsInPlace(listeners, InvocationKind.EXACTLY_ONCE)
     }
     return MessageSubscribersBuilder<MessagePacket<*, *>> { listener ->
-        this.subscribeAlways(coroutineContext) {
+        this.subscribeAlways(coroutineContext, concurrencyKind) {
             listener(this, this.message.toString())
         }
     }.run(listeners)
@@ -124,13 +129,14 @@ fun <R> Bot.subscribeMessages(
 @OptIn(ExperimentalContracts::class)
 fun <R> Bot.subscribeGroupMessages(
     coroutineContext: CoroutineContext = EmptyCoroutineContext,
+    concurrencyKind: Listener.ConcurrencyKind = Listener.ConcurrencyKind.CONCURRENT,
     listeners: MessageSubscribersBuilder<GroupMessage>.() -> R
 ): R {
     contract {
         callsInPlace(listeners, InvocationKind.EXACTLY_ONCE)
     }
     return MessageSubscribersBuilder<GroupMessage> { listener ->
-        this.subscribeAlways(coroutineContext) {
+        this.subscribeAlways(coroutineContext, concurrencyKind) {
             listener(this, this.message.toString())
         }
     }.run(listeners)
@@ -144,13 +150,14 @@ fun <R> Bot.subscribeGroupMessages(
 @OptIn(ExperimentalContracts::class)
 fun <R> Bot.subscribeFriendMessages(
     coroutineContext: CoroutineContext = EmptyCoroutineContext,
+    concurrencyKind: Listener.ConcurrencyKind = Listener.ConcurrencyKind.CONCURRENT,
     listeners: MessageSubscribersBuilder<FriendMessage>.() -> R
 ): R {
     contract {
         callsInPlace(listeners, InvocationKind.EXACTLY_ONCE)
     }
     return MessageSubscribersBuilder<FriendMessage> { listener ->
-        this.subscribeAlways(coroutineContext) {
+        this.subscribeAlways(coroutineContext, concurrencyKind) {
             listener(this, this.message.toString())
         }
     }.run(listeners)
@@ -170,10 +177,11 @@ fun <R> Bot.subscribeFriendMessages(
  */
 inline fun <reified E : Event> CoroutineScope.incoming(
     coroutineContext: CoroutineContext = EmptyCoroutineContext,
+    concurrencyKind: Listener.ConcurrencyKind = Listener.ConcurrencyKind.CONCURRENT,
     capacity: Int = Channel.UNLIMITED
 ): ReceiveChannel<E> {
     return Channel<E>(capacity).apply {
-        val listener = this@incoming.subscribeAlways<E>(coroutineContext) {
+        val listener = this@incoming.subscribeAlways<E>(coroutineContext, concurrencyKind) {
             send(this)
         }
         this.invokeOnClose {
@@ -183,6 +191,33 @@ inline fun <reified E : Event> CoroutineScope.incoming(
 }
 
 
+/**
+ * 打开一个来自指定 [Bot] 的指定事件的接收通道
+ *
+ * @param capacity 同 [Channel] 的参数, 参见 [Channel.Factory] 中的常量.
+ *
+ * @see capacity 默认无限大小. 详见 [Channel.Factory] 中的常量 [Channel.UNLIMITED], [Channel.CONFLATED], [Channel.RENDEZVOUS].
+ * 请谨慎使用 [Channel.RENDEZVOUS]: 在 [Channel] 未被 [接收][Channel.receive] 时他将会阻塞事件处理
+ *
+ * @see subscribeFriendMessages
+ * @see subscribeMessages
+ * @see subscribeGroupMessages
+ */
+inline fun <reified E : BotEvent> Bot.incoming(
+    coroutineContext: CoroutineContext = EmptyCoroutineContext,
+    concurrencyKind: Listener.ConcurrencyKind = Listener.ConcurrencyKind.CONCURRENT,
+    capacity: Int = Channel.UNLIMITED
+): ReceiveChannel<E> {
+    return Channel<E>(capacity).apply {
+        val listener = this@incoming.subscribeAlways<E>(coroutineContext, concurrencyKind) {
+            send(this)
+        }
+        this.invokeOnClose {
+            listener.cancel(CancellationException("ReceiveChannel closed", it))
+        }
+    }
+}
+
 /**
  * 消息事件的处理器.
  *