Introduce `AbstractEvent` acting as all events' super class

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

-/*
- * Copyright 2020 Mamoe Technologies and contributors.
- *
- * 此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
- * Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
- *
- * https://github.com/mamoe/mirai/blob/master/LICENSE
- */
-
-package net.mamoe.mirai.qqandroid.event
-
-import net.mamoe.mirai.qqandroid.network.Packet
-import net.mamoe.mirai.event.AbstractCancellableEvent
-import net.mamoe.mirai.event.Event
-
-/**
- * 接收到数据包
- */
-data class PacketReceivedEvent(val packet: Packet) : Event, AbstractCancellableEvent()
\ No newline at end of file

mirai-core-qqandroid/src/commonMain/kotlin/net/mamoe/mirai/qqandroid/network/QQAndroidBotNetworkHandler.kt

@@ -26,7 +26,6 @@ import net.mamoe.mirai.network.UnsupportedSMSLoginException
 import net.mamoe.mirai.network.WrongPasswordException
 import net.mamoe.mirai.qqandroid.QQAndroidBot
 import net.mamoe.mirai.qqandroid.contact.*
-import net.mamoe.mirai.qqandroid.event.PacketReceivedEvent
 import net.mamoe.mirai.qqandroid.network.protocol.data.jce.StTroopNum
 import net.mamoe.mirai.qqandroid.network.protocol.data.proto.MsgSvc
 import net.mamoe.mirai.qqandroid.network.protocol.packet.*
@@ -511,10 +510,6 @@ internal class QQAndroidBotNetworkHandler(coroutineContext: CoroutineContext, bo
             }
         }
 
-        if (packet != null && PacketReceivedEvent(packet).broadcast().isCancelled) {
-            return
-        }
-
         if (packet is Event) {
             if (packet is BroadcastControllable) {
                 if (packet.shouldBroadcast) packet.broadcast()

mirai-core-qqandroid/src/commonMain/kotlin/net/mamoe/mirai/qqandroid/network/protocol/packet/chat/receive/MessageSvc.kt

@@ -23,6 +23,7 @@ import net.mamoe.mirai.contact.Group
 import net.mamoe.mirai.contact.Member
 import net.mamoe.mirai.contact.MemberPermission
 import net.mamoe.mirai.data.MemberInfo
+import net.mamoe.mirai.event.AbstractEvent
 import net.mamoe.mirai.event.Event
 import net.mamoe.mirai.event.events.BotJoinGroupEvent
 import net.mamoe.mirai.event.events.BotOfflineEvent
@@ -36,7 +37,7 @@ import net.mamoe.mirai.qqandroid.contact.GroupImpl
 import net.mamoe.mirai.qqandroid.contact.checkIsFriendImpl
 import net.mamoe.mirai.qqandroid.contact.checkIsMemberImpl
 import net.mamoe.mirai.qqandroid.message.*
-import net.mamoe.mirai.qqandroid.network.MultiPacketByIterable
+import net.mamoe.mirai.qqandroid.network.MultiPacket
 import net.mamoe.mirai.qqandroid.network.Packet
 import net.mamoe.mirai.qqandroid.network.QQAndroidClient
 import net.mamoe.mirai.qqandroid.network.protocol.data.jce.RequestPushForceOffline
@@ -50,7 +51,6 @@ import net.mamoe.mirai.qqandroid.network.protocol.packet.*
 import net.mamoe.mirai.qqandroid.network.protocol.packet.chat.GroupInfoImpl
 import net.mamoe.mirai.qqandroid.network.protocol.packet.chat.NewContact
 import net.mamoe.mirai.qqandroid.network.protocol.packet.list.FriendList
-import net.mamoe.mirai.qqandroid.utils._miraiContentToString
 import net.mamoe.mirai.qqandroid.utils.io.serialization.readProtoBuf
 import net.mamoe.mirai.qqandroid.utils.io.serialization.readUniPacket
 import net.mamoe.mirai.qqandroid.utils.io.serialization.toByteArray
@@ -129,7 +129,10 @@ internal class MessageSvc {
          */
         @MiraiInternalAPI
         open class Response(internal val syncFlagFromServer: MsgSvc.SyncFlag, delegate: List<Packet>) :
-            MultiPacketByIterable<Packet>(delegate) {
+            AbstractEvent(),
+            MultiPacket<Packet>,
+            Iterable<Packet> by (delegate) {
+
             override fun toString(): String =
                 "MessageSvc.PbGetMsg.Response(syncFlagFromServer=$syncFlagFromServer, messages=<Iterable>))"
         }

mirai-core-qqandroid/src/commonMain/kotlin/net/mamoe/mirai/qqandroid/network/protocol/packet/chat/receive/OnlinePush.kt

@@ -17,6 +17,7 @@ import net.mamoe.mirai.LowLevelAPI
 import net.mamoe.mirai.contact.MemberPermission
 import net.mamoe.mirai.contact.nameCardOrNick
 import net.mamoe.mirai.data.FriendInfo
+import net.mamoe.mirai.event.AbstractEvent
 import net.mamoe.mirai.event.Event
 import net.mamoe.mirai.event.broadcast
 import net.mamoe.mirai.event.events.*
@@ -57,7 +58,7 @@ internal class OnlinePush {
         internal class SendGroupMessageReceipt(
             val messageRandom: Int,
             val sequenceId: Int
-        ) : Packet, Event, Packet.NoLog {
+        ) : Packet, Event, Packet.NoLog, AbstractEvent() {
             override fun toString(): String {
                 return "OnlinePush.PbPushGroupMsg.SendGroupMessageReceipt(messageRandom=$messageRandom, sequenceId=$sequenceId)"
             }

mirai-core-qqandroid/src/commonMain/kotlin/net/mamoe/mirai/qqandroid/network/protocol/packet/login/ConfigPushSvc.kt

@@ -12,6 +12,7 @@ package net.mamoe.mirai.qqandroid.network.protocol.packet.login
 import kotlinx.io.core.ByteReadPacket
 import kotlinx.serialization.Serializable
 import kotlinx.serialization.protobuf.ProtoId
+import net.mamoe.mirai.event.AbstractEvent
 import net.mamoe.mirai.event.Event
 import net.mamoe.mirai.qqandroid.QQAndroidBot
 import net.mamoe.mirai.qqandroid.network.Packet
@@ -39,7 +40,7 @@ internal class ConfigPushSvc {
     ) {
         override val canBeCached: Boolean get() = false
 
-        sealed class PushReqResponse : Packet, Event {
+        sealed class PushReqResponse : Packet, Event, AbstractEvent() {
             class Success(
                 val struct: PushReqJceStruct
             ) : PushReqResponse() {

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

@@ -11,14 +11,20 @@
 
 package net.mamoe.mirai.event
 
+import kotlinx.atomicfu.atomic
 import net.mamoe.mirai.event.internal.broadcastInternal
 import net.mamoe.mirai.utils.MiraiInternalAPI
+import net.mamoe.mirai.utils.PlannedRemoval
+import net.mamoe.mirai.utils.SinceMirai
+import kotlin.jvm.JvmSynthetic
 
 /**
  * 可被监听的类, 可以是任何 class 或 object.
  *
  * 若监听这个类, 监听器将会接收所有事件的广播.
  *
+ * 所有 [Event] 都应继承 [AbstractEvent] 而不要直接实现 [Event]. 否则将无法广播也无法监听.
+ *
  * @see subscribeAlways
  * @see subscribeOnce
  *
@@ -27,40 +33,83 @@ import net.mamoe.mirai.utils.MiraiInternalAPI
  * @see [broadcast] 广播事件
  * @see [subscribe] 监听事件
  */
-interface Event
+interface Event {
+
+    @Deprecated("""
+        Don't implement Event but extend AbstractEvent instead.
+    """, level = DeprecationLevel.HIDDEN) // so Kotlin class won't be compiled.
+    @Suppress("WRONG_MODIFIER_CONTAINING_DECLARATION", "PropertyName")
+    @get:JvmSynthetic // so Java user won't see it
+    internal val DoNotImplementThisClassButExtendAbstractEvent: Nothing
+}
 
 /**
- * 可被取消的事件
+ * 所有实现了 [Event] 接口的类都应该继承的父类.
  */
-interface CancellableEvent {
+@SinceMirai("1.0.0")
+abstract class AbstractEvent : Event {
+    @Suppress("WRONG_MODIFIER_CONTAINING_DECLARATION", "PropertyName")
+    @get:JvmSynthetic // so Java user won't see it
+    @Deprecated("", level = DeprecationLevel.HIDDEN)
+    final override val DoNotImplementThisClassButExtendAbstractEvent: Nothing
+        get() = throw Error("Shouldn't be reached")
+
+    private val _intercepted = atomic(false)
+    private val _cancelled = atomic(false)
+
+
+    /**
+     * 事件是否已被拦截.
+     *
+     * 所有事件都可以被拦截, 拦截后低优先级的监听器将不会处理到这个事件.
+     */
+    @SinceMirai("1.0.0")
+    val isIntercepted: Boolean
+        get() = _intercepted.value
+
+    /**
+     * 拦截这个事件.
+     * 重复拦截时不会抛出异常.
+     */
+    @SinceMirai("1.0.0")
+    fun intercept() {
+        _intercepted.value = true
+    }
+
+
     /**
      * 事件是否已取消.
+     *
+     * 事件需实现 [CancellableEvent] 接口才可以被取消,
+     * 否则此属性固定返回 false.
      */
-    val isCancelled: Boolean
+    val isCancelled: Boolean get() = _cancelled.value
 
     /**
      * 取消这个事件.
+     * 重复取消时不会抛出异常.
      */
-    fun cancel()
+    fun cancel() {
+        check(this is CancellableEvent) {
+            "Event $this is not cancellable"
+        }
+        _cancelled.value = true
+    }
 }
 
 /**
- * 可被取消的事件的实现
+ * 可被取消的事件
  */
-abstract class AbstractCancellableEvent : Event, CancellableEvent {
+interface CancellableEvent : Event {
     /**
      * 事件是否已取消.
      */
-    override val isCancelled: Boolean get() = _cancelled
-
-    private var _cancelled: Boolean = false
+    val isCancelled: Boolean
 
     /**
-     * 取消事件.
+     * 取消这个事件.
      */
-    override fun cancel() {
-        _cancelled = true
-    }
+    fun cancel()
 }
 
 /**
@@ -81,9 +130,20 @@ suspend fun <E : Event> E.broadcast(): E = apply {
 var EventDisabled = false
 
 /**
- * 可控制是否需要广播这个事件包
+ * 可控制是否需要广播这个事件
  */
 interface BroadcastControllable : Event {
+    /**
+     * 返回 `false` 时将不会广播这个事件.
+     */
     val shouldBroadcast: Boolean
         get() = true
-}
\ No newline at end of file
+}
+
+
+@PlannedRemoval("1.1.0")
+@Deprecated(
+    "use AbstractEvent and implement CancellableEvent",
+    level = DeprecationLevel.ERROR,
+    replaceWith = ReplaceWith("AbstractEvent", "net.mamoe.mirai.event.AbstractEvent"))
+abstract class AbstractCancellableEvent : AbstractEvent(), CancellableEvent

mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/ContactMessage.kt

@@ -24,11 +24,8 @@ import kotlinx.coroutines.async
 import kotlinx.coroutines.io.ByteReadChannel
 import net.mamoe.mirai.Bot
 import net.mamoe.mirai.contact.*
+import net.mamoe.mirai.event.*
 import net.mamoe.mirai.event.events.BotEvent
-import net.mamoe.mirai.event.selectMessages
-import net.mamoe.mirai.event.syncFromEvent
-import net.mamoe.mirai.event.syncFromEventOrNull
-import net.mamoe.mirai.event.whileSelectMessages
 import net.mamoe.mirai.message.data.*
 import net.mamoe.mirai.qqandroid.network.Packet
 import net.mamoe.mirai.utils.*
@@ -71,7 +68,7 @@ expect abstract class MessagePacket<TSender : User, TSubject : Contact> construc
     replaceWith = ReplaceWith("ContactMessage", "net.mamoe.mirai.message.ContactMessage")
 )
 @Suppress("NOTHING_TO_INLINE", "UNCHECKED_CAST")
-abstract class MessagePacketBase<out TSender : User, out TSubject : Contact> : Packet, BotEvent {
+abstract class MessagePacketBase<out TSender : User, out TSubject : Contact> : Packet, BotEvent, AbstractEvent() {
     /**
      * 接受到这条消息的
      */

mirai-core/src/jvmTest/kotlin/net/mamoe/mirai/event/EventTests.kt

@@ -15,7 +15,7 @@ import net.mamoe.mirai.utils.internal.runBlocking
 import kotlin.test.Test
 import kotlin.test.assertTrue
 
-class TestEvent : Event {
+class TestEvent : Event, AbstractEvent() {
     var triggered = false
 }
 
@@ -44,7 +44,7 @@ class EventTests {
     }
 
 
-    open class ParentEvent : Event {
+    open class ParentEvent : Event, AbstractEvent() {
         var triggered = false
     }