Make MessageChain implement List<SingleMessage>;

Hide relevant APIs on `Iterable`;
Deprecate `__forEachForJava__` in favor of Java 8 API;
Add `fun messageChainOf(vararg messages: Message): MessageChain`;
Add `fun Array<out Message>.asMessageChain(): MessageChain`;
Add `fun Array<out SingleMessage>.asMessageChain(): MessageChain`;
Add `fun Array<out Message>.flatten(): Sequence<SingleMessage>`;
Add `fun Array<out SingleMessage>.flatten(): Sequence<SingleMessage>`;
Close #312

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

@@ -13,11 +13,10 @@
 package net.mamoe.mirai.message.data
 
 import net.mamoe.mirai.utils.MiraiExperimentalAPI
-import net.mamoe.mirai.utils.MiraiInternalAPI
+import net.mamoe.mirai.utils.PlannedRemoval
 import kotlin.jvm.JvmField
 import kotlin.jvm.JvmMultifileClass
 import kotlin.jvm.JvmName
-import kotlin.jvm.JvmSynthetic
 
 /**
  * 快速链接的两个消息 (避免构造新的 list).
@@ -33,26 +32,23 @@ internal class CombinedMessage
 internal constructor(
     @JvmField internal val left: Message, // 必须已经完成 constrain single
     @JvmField internal val tail: Message
-) : Message, MessageChain {
+) : Message, MessageChain, List<SingleMessage> by (left.flatten() + tail.flatten()).toList() {
 
-    fun asSequence(): Sequence<SingleMessage> = sequence {
-        yieldCombinedOrElementsFlatten(this@CombinedMessage)
-    }
-
-    override fun iterator(): Iterator<SingleMessage> {
-        return asSequence().iterator()
-    }
-
-    override val size: Int
-        get() = kotlin.run {
-            var size = 0
-            size += if (left is MessageChain) left.size else 1
-            size += if (tail is MessageChain) tail.size else 1
-            size
-        }
+    @PlannedRemoval("1.2.0")
+    @Deprecated(
+        "use asSequence from stdlib",
+        ReplaceWith("(this as List<SingleMessage>).asSequence()"),
+        level = DeprecationLevel.HIDDEN
+    )
+    @Suppress("INVISIBLE_REFERENCE", "INVISIBLE_MEMBER")
+    @kotlin.internal.LowPriorityInOverloadResolution // resolve to extension from stdlib
+    fun asSequence(): Sequence<SingleMessage> = (this as List<SingleMessage>).asSequence()
 
     override fun equals(other: Any?): Boolean {
-        return other is CombinedMessage && other.left == this.left && other.tail == this.tail
+        if (other == null) return false
+        if (other::class != CombinedMessage::class) return false
+        other as CombinedMessage
+        return other.left == this.left && other.tail == this.tail
     }
 
     private var toStringCache: String? = null
@@ -71,6 +67,7 @@ internal constructor(
     }
 }
 
+/*
 @JvmSynthetic
 // 不要把它用作 local function, 会编译错误
 @OptIn(MiraiExperimentalAPI::class, MiraiInternalAPI::class)
@@ -93,3 +90,4 @@ private suspend fun SequenceScope<SingleMessage>.yieldCombinedOrElementsFlatten(
         }
     }
 }
+*/

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

@@ -196,6 +196,7 @@ fun Iterable<MessageEvent>.toForwardMessage(displayStrategy: DisplayStrategy = D
 /**
  * 转换为 [ForwardMessage]
  */
+@JvmOverloads
 fun Message.toForwardMessage(
     sender: User,
     time: Int = currentTimeSeconds.toInt(),

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

@@ -33,6 +33,10 @@ import kotlin.reflect.KProperty
  * 要获取更多消息相关的信息, 查看 [Message]
  *
  * ### 构造消息链
+ * - [buildMessageChain]: 使用构建器
+ * - [Message.plus]: 将两个消息相连成为一个消息链
+ * - [asMessageChain] 将 [Iterable], 等类型消息
+ * - [messageChainOf] 类似 [listOf], 将多个 [Message] 构造为 [MessageChain]
  *
  * ### 消息链如何工作
  * - [SingleMessageChainImpl] 将 [单个消息][SingleMessage] 委托为一个 [MessageChain]
@@ -54,7 +58,8 @@ import kotlin.reflect.KProperty
  * @see getValue 属性委托扩展
  * @see flatten 扁平化
  */
-interface MessageChain : Message, Iterable<SingleMessage> {
+@Suppress("FunctionName", "DeprecatedCallableAddReplaceWith", "INVISIBLE_MEMBER", "INVISIBLE_REFERENCE")
+interface MessageChain : Message, List<SingleMessage>, RandomAccess {
     /**
      * 元素数量. [EmptyMessageChain] 不参加计数.
      */
@@ -72,35 +77,22 @@ interface MessageChain : Message, Iterable<SingleMessage> {
      * 遍历每一个有内容的消息, 即 [At], [AtAll], [PlainText], [Image], [Face] 等
      * 仅供 `Java` 使用
      */
-    @Suppress("FunctionName")
-    @JsName("forEachContent")
     @JvmName("forEachContent")
     @JavaFriendlyAPI
-    final fun __forEachContentForJava__(block: (Message) -> Unit) {
-        this.forEachContent(block)
-    }
+    final fun __forEachContentForJava__(block: (Message) -> Unit) = this.forEachContent(block)
 
-    /**
-     * 遍历每一个消息, 即 [MessageSource] [At], [AtAll], [PlainText], [Image], [QuoteReply] 等
-     * 仅供 `Java` 使用
-     */
-    @Suppress("FunctionName")
-    @JsName("forEach")
+
+    @PlannedRemoval("1.1.0")
+    @Deprecated("use Java 8 API", level = DeprecationLevel.HIDDEN)
     @JvmName("forEach")
     @JavaFriendlyAPI
-    final fun __forEachForJava__(block: (Message) -> Unit) {
-        this.forEach(block)
-    }
+    @JvmSynthetic
+    @kotlin.internal.LowPriorityInOverloadResolution
+    final fun __forEachForJava__(block: (Message) -> Unit) = this.forEach(block)
 
-
-    /**
-     * 获取第一个类型为 [key] 的 [Message] 实例, 找不到则返回 `null`
-     *
-     * @param key 由各个类型消息的伴生对象持有. 如 [PlainText.Key]
-     */
     @PlannedRemoval("1.2.0")
     @JvmName("firstOrNull")
-    @Deprecated("use get", ReplaceWith("get(key)"))
+    @Deprecated("use get instead. This is going to be removed in mirai 1.2.0", ReplaceWith("get(key)"))
     final fun <M : Message> getOrNull(key: Message.Key<M>): M? = get(key)
 }
 
@@ -271,6 +263,13 @@ inline fun <reified T : Message?> MessageChain.orElse(
 
 
 // region asMessageChain
+
+/**
+ * 返回一个包含 [messages] 所有元素的消息链, 保留顺序.
+ */
+@JvmName("newChain")
+inline fun messageChainOf(vararg messages: Message): MessageChain = messages.asMessageChain()
+
 /**
  * 得到包含 [this] 的 [MessageChain].
  *
@@ -301,6 +300,18 @@ fun SingleMessage.asMessageChain(): MessageChain = SingleMessageChainImpl(this)
 fun Collection<SingleMessage>.asMessageChain(): MessageChain =
     MessageChainImplByCollection(this.constrainSingleMessages())
 
+/**
+ * 将 [this] [扁平化后][flatten] 委托为一个 [MessageChain]
+ */
+@JvmSynthetic
+@JvmName("newChain1")
+// @JsName("newChain")
+fun Array<out Message>.asMessageChain(): MessageChain = MessageChainImplBySequence(this.flatten())
+
+@JvmSynthetic
+@JvmName("newChain2")
+fun Array<out SingleMessage>.asMessageChain(): MessageChain = MessageChainImplBySequence(this.asSequence())
+
 /**
  * 将 [this] [扁平化后][flatten] 委托为一个 [MessageChain]
  */
@@ -316,7 +327,7 @@ fun Iterable<SingleMessage>.asMessageChain(): MessageChain =
     MessageChainImplByCollection(this.constrainSingleMessages())
 
 @JvmSynthetic
-fun MessageChain.asMessageChain(): MessageChain = this // 避免套娃
+inline fun MessageChain.asMessageChain(): MessageChain = this // 避免套娃
 
 /**
  * 将 [this] [扁平化后][flatten] 委托为一个 [MessageChain]
@@ -338,15 +349,6 @@ fun Sequence<SingleMessage>.asMessageChain(): MessageChain = MessageChainImplByS
 // @JsName("newChain")
 fun Sequence<Message>.asMessageChain(): MessageChain = MessageChainImplBySequence(this.flatten())
 
-/**
- * 构造一个 [MessageChain]
- * 为提供更好的 Java API.
- */
-@Suppress("FunctionName")
-@JvmName("newChain")
-fun _____newChain______(vararg messages: Message): MessageChain {
-    return messages.asIterable().asMessageChain()
-}
 
 /**
  * 构造一个 [MessageChain]
@@ -396,6 +398,10 @@ inline fun Sequence<Message>.flatten(): Sequence<SingleMessage> = flatMap { it.f
 @JvmSynthetic
 inline fun Sequence<SingleMessage>.flatten(): Sequence<SingleMessage> = this // fast path
 
+inline fun Array<out Message>.flatten(): Sequence<SingleMessage> = this.asSequence().flatten()
+
+inline fun Array<out SingleMessage>.flatten(): Sequence<SingleMessage> = this.asSequence() // fast path
+
 /**
  * 扁平化 [Message]
  *

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

@@ -33,7 +33,7 @@ import kotlin.jvm.JvmSynthetic
  *
  *
  * ### 组成
- * MessageSource 由 metadata (元数据), form & target, content 组成
+ * [MessageSource] 由 metadata (元数据), form & target, content 组成
  *
  * #### metadata
  * - [id] 消息 id (序列号)

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

@@ -245,8 +245,8 @@ internal fun <M : Message> MessageChain.firstOrNullImpl(key: Message.Key<M>): M?
  * 使用 [Collection] 作为委托的 [MessageChain]
  */
 internal class MessageChainImplByCollection constructor(
-    internal val delegate: Collection<SingleMessage> // 必须 constrainSingleMessages, 且为 immutable
-) : Message, Iterable<SingleMessage>, MessageChain {
+    internal val delegate: List<SingleMessage> // 必须 constrainSingleMessages, 且为 immutable
+) : Message, MessageChain, List<SingleMessage> by delegate {
     override val size: Int get() = delegate.size
     override fun iterator(): Iterator<SingleMessage> = delegate.iterator()
 
@@ -266,15 +266,7 @@ internal class MessageChainImplByCollection constructor(
  */
 internal class MessageChainImplBySequence constructor(
     delegate: Sequence<SingleMessage> // 可以有重复 ConstrainSingle
-) : Message, Iterable<SingleMessage>, MessageChain {
-    override val size: Int by lazy { collected.size }
-
-    /**
-     * [Sequence] 可能只能消耗一遍, 因此需要先转为 [List]
-     */
-    private val collected: List<SingleMessage> by lazy { delegate.constrainSingleMessages() }
-    override fun iterator(): Iterator<SingleMessage> = collected.iterator()
-
+) : Message, Iterable<SingleMessage>, MessageChain, List<SingleMessage> by delegate.constrainSingleMessages() {
     private var toStringTemp: String? = null
         get() = field ?: this.joinToString("") { it.toString() }.also { field = it }
 
@@ -291,11 +283,9 @@ internal class MessageChainImplBySequence constructor(
  */
 internal class SingleMessageChainImpl constructor(
     internal val delegate: SingleMessage
-) : Message, Iterable<SingleMessage>, MessageChain {
-    override val size: Int get() = 1
+) : Message, MessageChain, List<SingleMessage> by listOf(delegate) {
     override fun toString(): String = this.delegate.toString()
     override fun contentToString(): String = this.delegate.contentToString()
-    override fun iterator(): Iterator<SingleMessage> = iterator { yield(delegate) }
 }