Powerful MessageChains

mirai-core/src/commonMain/kotlin/net.mamoe.mirai/contact/Contact.kt

@@ -24,15 +24,8 @@ sealed class Contact(val bot: Bot, val id: UInt) {
 
     abstract suspend fun sendMessage(message: MessageChain)
 
-    suspend fun sendMessage(message: Message) {
-        if (message is MessageChain) {
-            return sendMessage(message)
-        }
-        return sendMessage(message.toChain())
-    }
-
-    suspend fun sendMessage(plain: String) = this.sendMessage(PlainText(plain))
-
+    suspend fun sendMessage(message: Message) = sendMessage(message.toChain())
+    suspend fun sendMessage(plain: String) = sendMessage(PlainText(plain))
 
     abstract suspend fun sendXMLMessage(message: String)
 }

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

@@ -70,8 +70,8 @@ interface Message {
      * ```
      */
     fun concat(tail: Message): MessageChain =
-        if (tail is MessageChain) MessageChain(this).also { tail.forEach { child -> it.concat(child) } }
-        else MessageChain(this, tail)
+        if (tail is MessageChain) tail.concat(this)/*MessageChainImpl(this).also { tail.forEach { child -> it.concat(child) } }*/
+        else MessageChainImpl(this, tail)
 
     infix operator fun plus(another: Message): MessageChain = this.concat(another)
     infix operator fun plus(another: String): MessageChain = this.concat(another.toMessage())
@@ -129,23 +129,142 @@ inline class Face(val id: FaceID) : Message {
 }
 
 // ==================================== MessageChain ====================================
+
+/**
+ * 构造无初始元素的可修改的 [MessageChain]. 初始大小将会被设定为 8
+ */
+@Suppress("FunctionName")
+fun MessageChain(): MessageChain = MessageChainImpl(ArrayList(8))
+
+/**
+ * 构造无初始元素的可修改的 [MessageChain]. 初始大小将会被设定为 [initialCapacity]
+ */
+@Suppress("FunctionName")
+fun MessageChain(initialCapacity: Int): MessageChain = MessageChainImpl(ArrayList(initialCapacity))
+
+/**
+ * 构造 [MessageChain]
+ * 若仅提供一个参数, 请考虑使用 [Message.toChain] 以优化性能
+ */
+@Suppress("FunctionName")
+fun MessageChain(vararg messages: Message): MessageChain = MessageChainImpl(messages.toMutableList())
+
+/**
+ * 构造 [MessageChain]
+ */
+@Suppress("FunctionName")
+fun MessageChain(messages: Iterable<Message>): MessageChain = MessageChainImpl(messages.toMutableList())
+
+/**
+ * 构造单元素的不可修改的 [MessageChain]. 内部类实现为 [SingleMessageChain]
+ *
+ * 参数 [delegate] 不能为 [MessageChain] 的实例, 否则将会抛出异常.
+ * 使用 [Message.toChain] 将帮助提前处理这个问题.
+ *
+ * @param delegate 所构造的单元素 [MessageChain] 代表的 [Message]
+ * @throws IllegalArgumentException 当 [delegate] 为 [MessageChain] 的实例时
+ * @see Message.toChain 将
+ */
+@Suppress("FunctionName")
+fun SingleMessageChain(delegate: Message): MessageChain {
+    require(delegate !is MessageChain) { "delegate for SingleMessageChain should not be any instance of MessageChain" }
+    return SingleMessageChainImpl(delegate)
+}
+
 /**
  * 消息链. 即 MutableList<Message>.
- * 它是一个特殊的 [Message], 实现 [MutableList] 接口, 但将所有的接口调用都转到内部维护的另一个 [MutableList], [delegate]
+ * 它的一般实现为 [MessageChainImpl], `null` 实现为 [NullMessageChain]
  *
  * 有关 [MessageChain] 的创建和连接:
  * - 当任意两个不是 [MessageChain] 的 [Message] 相连接后, 将会产生一个 [MessageChain].
- * - 若两个 [MessageChain] 连接, 后一个将会被添加到第一个内.
+ * - 若两个 [MessageChain] 连接, 后一个将会被合并到第一个内.
  * - 若一个 [MessageChain] 与一个其他 [Message] 连接, [Message] 将会被添加入 [MessageChain].
- * - 若一个 [Message] 与一个 [MessageChain] 连接, 将会创建一个新的 [MessageChain], 并顺序添加连接时的参数.
+ * - 若一个 [Message] 与一个 [MessageChain] 连接, [Message] 将会被添加入 [MessageChain].
  */
-inline class MessageChain constructor(
+interface MessageChain : Message, MutableList<Message> {
+    // region Message override
+    override val stringValue: String
+
+    override operator fun contains(sub: String): Boolean
+    override fun concat(tail: Message): MessageChain
+    // endregion
+
+    operator fun plusAssign(message: Message) {
+        this.concat(message)
+    }
+
+    operator fun plusAssign(plain: String) {
+        this.concat(plain.toMessage())
+    }
+}
+
+/**
+ * Null 的 [MessageChain].
+ * 它不包含任何元素, 也没有创建任何 list.
+ *
+ * - 所有 get 方法均抛出 [NoSuchElementException]
+ * - 所有 add 方法均抛出 [UnsupportedOperationException]
+ * - 其他判断类方法均 false 或 -1
+ */
+object NullMessageChain : MessageChain {
+    override fun subList(fromIndex: Int, toIndex: Int): MutableList<Message> = unsupported()
+
+    override val stringValue: String
+        get() = ""
+
+    override fun contains(sub: String): Boolean = false
+    override fun contains(element: Message): Boolean = false
+    override fun concat(tail: Message): MessageChain = MessageChainImpl(tail)
+    override val size: Int = 0
+    override fun containsAll(elements: Collection<Message>): Boolean = false
+    override fun get(index: Int): Message = throw NoSuchElementException()
+    override fun indexOf(element: Message): Int = -1
+    override fun isEmpty(): Boolean = true
+    override fun iterator(): MutableIterator<Message> = object : MutableIterator<Message> {
+        override fun hasNext(): Boolean = false
+        override fun next(): Message = throw NoSuchElementException()
+        override fun remove() = throw NoSuchElementException()
+    }
+
+    override fun lastIndexOf(element: Message): Int = -1
+    override fun add(element: Message): Boolean = unsupported()
+    override fun add(index: Int, element: Message) = unsupported()
+    override fun addAll(index: Int, elements: Collection<Message>): Boolean = unsupported()
+    override fun addAll(elements: Collection<Message>): Boolean = unsupported()
+    override fun clear() {}
+    override fun listIterator(): MutableListIterator<Message> = object : MutableListIterator<Message> {
+        override fun hasPrevious(): Boolean = false
+        override fun nextIndex(): Int = -1
+        override fun previous(): Message = throw NoSuchElementException()
+        override fun previousIndex(): Int = -1
+        override fun add(element: Message) = unsupported()
+        override fun hasNext(): Boolean = false
+        override fun next(): Message = throw NoSuchElementException()
+        override fun remove() = throw NoSuchElementException()
+        override fun set(element: Message) = unsupported()
+    }
+
+    override fun listIterator(index: Int): MutableListIterator<Message> = unsupported()
+    override fun remove(element: Message): Boolean = false
+    override fun removeAll(elements: Collection<Message>): Boolean = false
+    override fun removeAt(index: Int): Message = throw NoSuchElementException()
+    override fun retainAll(elements: Collection<Message>): Boolean = false
+    override fun set(index: Int, element: Message): Message = unsupported()
+    private fun unsupported(): Nothing = throw UnsupportedOperationException()
+}
+
+/**
+ * [MessageChain] 实现
+ * 它是一个特殊的 [Message], 实现 [MutableList] 接口, 但将所有的接口调用都转到内部维护的另一个 [MutableList].
+ */
+internal inline class MessageChainImpl constructor(
     /**
      * Elements will not be instances of [MessageChain]
      */
     private val delegate: MutableList<Message>
-) : Message, MutableList<Message> {
+) : Message, MutableList<Message>, MessageChain {
     constructor() : this(ArrayList(8))
+    constructor(initialCapacity: Int) : this(ArrayList(initialCapacity))
     constructor(vararg messages: Message) : this(messages.toMutableList())
     constructor(messages: Iterable<Message>) : this(messages.toMutableList())
 
@@ -154,33 +273,20 @@ inline class MessageChain constructor(
 
     override operator fun contains(sub: String): Boolean = delegate.any { it.contains(sub) }
     override fun concat(tail: Message): MessageChain {
-        if (tail is MessageChain) tail.delegate.forEach { child -> this.concat(child) }
+        if (tail is MessageChain) tail.forEach { child -> this.concat(child) }
         else this.delegate.add(tail)
         return this
     }
-    // endregion
 
-    /**
-     * 获取第一个 [M] 类型的实例
-     * @throws [NoSuchElementException] 如果找不到该类型的实例
-     */
-    inline fun <reified M : Message> first(): Message = this.first { M::class.isInstance(it) }
-
-    /**
-     * 获取第一个 [M] 类型的实例
-     */
-    inline fun <reified M : Message> firstOrNull(): Message? = this.firstOrNull { M::class.isInstance(it) }
-
-
-    operator fun plusAssign(message: Message) {
+    // endregion
+    override operator fun plusAssign(message: Message) {
         this.concat(message)
     }
 
-    operator fun plusAssign(plain: String) {
+    override operator fun plusAssign(plain: String) {
         this.concat(plain.toMessage())
     }
 
-
     // region MutableList override
     override fun containsAll(elements: Collection<Message>): Boolean = delegate.containsAll(elements)
 
@@ -206,3 +312,95 @@ inline class MessageChain constructor(
     override val size: Int get() = delegate.size
     // endregion
 }
+
+/**
+ * 单个成员的不可修改的 [MessageChain].
+ * 在连接时将会把它当做一个普通 [Message] 看待.
+ */
+internal inline class SingleMessageChainImpl(
+    private val delegate: Message
+) : Message, MutableList<Message>, MessageChain {
+
+    // region Message override
+    override val stringValue: String get() = this.delegate.stringValue
+
+    override operator fun contains(sub: String): Boolean = delegate.contains(sub)
+    override fun concat(tail: Message): MessageChain {
+        if (tail is MessageChain) tail.forEach { child -> this.concat(child) }
+        else MessageChain(delegate, tail)
+        return this
+    }
+
+    // endregion
+    // region MutableList override
+    override fun containsAll(elements: Collection<Message>): Boolean = elements.all { it === delegate }
+
+    override operator fun get(index: Int): Message = if (index == 0) delegate else throw NoSuchElementException()
+    override fun indexOf(element: Message): Int = if (delegate === element) 0 else -1
+    override fun isEmpty(): Boolean = false
+    override fun lastIndexOf(element: Message): Int = if (delegate === element) 0 else -1
+    override fun add(element: Message): Boolean = throw UnsupportedOperationException()
+    override fun add(index: Int, element: Message) = throw UnsupportedOperationException()
+    override fun addAll(index: Int, elements: Collection<Message>): Boolean = throw UnsupportedOperationException()
+    override fun addAll(elements: Collection<Message>): Boolean = throw UnsupportedOperationException()
+    override fun clear() = throw UnsupportedOperationException()
+    override fun listIterator(): MutableListIterator<Message> = object : MutableListIterator<Message> {
+        private var hasNext = true
+        override fun hasPrevious(): Boolean = false
+        override fun nextIndex(): Int = if (hasNext) 0 else -1
+        override fun previous(): Message = throw NoSuchElementException()
+        override fun previousIndex(): Int = -1
+        override fun add(element: Message) = throw UnsupportedOperationException()
+        override fun hasNext(): Boolean = !hasNext
+        override fun next(): Message =
+            if (hasNext) {
+                hasNext = false
+                this@SingleMessageChainImpl
+            } else throw NoSuchElementException()
+
+        override fun remove() = throw UnsupportedOperationException()
+        override fun set(element: Message) = throw UnsupportedOperationException()
+    }
+
+    override fun listIterator(index: Int): MutableListIterator<Message> = throw UnsupportedOperationException()
+    override fun remove(element: Message): Boolean = throw UnsupportedOperationException()
+    override fun removeAll(elements: Collection<Message>): Boolean = throw UnsupportedOperationException()
+    override fun removeAt(index: Int): Message = throw UnsupportedOperationException()
+    override fun retainAll(elements: Collection<Message>): Boolean = throw UnsupportedOperationException()
+    override fun set(index: Int, element: Message): Message = throw UnsupportedOperationException()
+    override fun subList(fromIndex: Int, toIndex: Int): MutableList<Message> {
+        return if (fromIndex == 0) when (toIndex) {
+            1 -> mutableListOf<Message>(this)
+            0 -> mutableListOf()
+            else -> throw UnsupportedOperationException()
+        }
+        else throw UnsupportedOperationException()
+    }
+
+    override fun iterator(): MutableIterator<Message> = object : MutableIterator<Message> {
+        private var hasNext = true
+        override fun hasNext(): Boolean = !hasNext
+        override fun next(): Message =
+            if (hasNext) {
+                hasNext = false
+                this@SingleMessageChainImpl
+            } else throw NoSuchElementException()
+
+        override fun remove() = throw UnsupportedOperationException()
+    }
+
+    override operator fun contains(element: Message): Boolean = element === delegate
+    override val size: Int get() = 1
+    // endregion
+}
+
+/**
+ * 获取第一个 [M] 类型的实例
+ */
+inline fun <reified M : Message> MessageChain.firstOrNull(): Message? = this.firstOrNull { M::class.isInstance(it) }
+
+/**
+ * 获取第一个 [M] 类型的实例
+ * @throws [NoSuchElementException] 如果找不到该类型的实例
+ */
+inline fun <reified M : Message> MessageChain.first(): Message = this.first { M::class.isInstance(it) }
\ No newline at end of file

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

@@ -7,9 +7,20 @@ package net.mamoe.mirai.message
 fun String.toMessage(): PlainText = PlainText(this)
 
 /**
- * 构造 [MessageChain]
+ * 得到包含 [this] 的 [MessageChain].
+ * 若 [this] 为 [MessageChain] 将直接返回 this
+ * 否则将调用 [SingleMessageChain] 构造一个唯一成员不可修改的 [SingleMessageChainImpl]
+ *
+ * @see SingleMessageChain
+ * @see SingleMessageChainImpl
+ */
+fun Message.toChain(): MessageChain = if (this is MessageChain) this else SingleMessageChain(this)
+
+/**
+ * 以 [this] 为代表 (delegate) 构造 [SingleMessageChain].
+ * @throws IllegalArgumentException 当 [this] 为 [MessageChain] 的实例时
  */
-fun Message.toChain(): MessageChain = if (this is MessageChain) this else MessageChain(this)
+fun Message.singleChain(): MessageChain = SingleMessageChain(this)
 
 /**
  * 构造 [MessageChain]

mirai-core/src/commonMain/kotlin/net.mamoe.mirai/network/protocol/tim/packet/event/MessageEventPackets.kt

@@ -6,6 +6,7 @@ import kotlinx.io.core.ByteReadPacket
 import kotlinx.io.core.discardExact
 import kotlinx.io.core.readUInt
 import net.mamoe.mirai.message.MessageChain
+import net.mamoe.mirai.message.NullMessageChain
 import net.mamoe.mirai.message.internal.readMessageChain
 import net.mamoe.mirai.utils.io.*
 import kotlin.properties.Delegates
@@ -26,7 +27,7 @@ class ServerGroupMessageEventPacket(input: ByteReadPacket, eventIdentity: EventP
      * 发送方权限.
      */
     lateinit var senderPermission: SenderPermission
-    var message: MessageChain by Delegates.notNull()
+    var message: MessageChain = NullMessageChain
 
     override fun decode() = with(input) {
         discardExact(31)

mirai-core/src/jvmMain/kotlin/net/mamoe/mirai/network/protocol/tim/packet/PacketInternalJvm.kt

@@ -36,15 +36,17 @@ private object IgnoreIdList : List<String> by listOf(
     "EMPTY_ID_HEX",
     "input",
     "output",
+    "this\$0",
+    "\$\$delegatedProperties",
     "UninitializedByteReadPacket",
     "sessionKey"
 )
 
 internal actual fun Packet.packetToString(): String = PacketNameFormatter.adjustName(this::class.simpleName + "(${this.idHexString})") + this::class.java.allDeclaredFields
-        .filterNot { it.name in IgnoreIdList || /*"delegate" in it.name||*/ "$" in it.name }
+    .filterNot { it.name in IgnoreIdList /*|| "delegate" in it.name|| "$" in it.name */ }
     .joinToString(", ", "{", "}") {
         it.isAccessible = true
-            it.name + "=" + it.get(this).let { value ->
+        it.name.replace("\$delegate", "") + "=" + it.get(this).let { value ->
             when (value) {
                 null -> null
                 is ByteArray -> value.toUHexString()
@@ -52,6 +54,7 @@ internal actual fun Packet.packetToString(): String = PacketNameFormatter.adjust
                 is ByteReadPacket -> "[ByteReadPacket(${value.remaining})]"
                 //is ByteReadPacket -> value.copy().readBytes().toUHexString()
                 is IoBuffer -> "[IoBuffer(${value.readRemaining})]"
+                is Lazy<*> -> "[Lazy]"
                 else -> value.toString()
             }
         }

mirai-demos/mirai-demo-1/src/main/java/demo1/Main.kt

@@ -15,6 +15,7 @@ import net.mamoe.mirai.login
 import net.mamoe.mirai.message.Image
 import net.mamoe.mirai.message.ImageId
 import net.mamoe.mirai.message.PlainText
+import net.mamoe.mirai.message.firstOrNull
 import net.mamoe.mirai.network.protocol.tim.packet.OutgoingRawPacket
 import net.mamoe.mirai.network.protocol.tim.packet.login.LoginResult
 import net.mamoe.mirai.network.protocol.tim.packet.uploadImage