Add channel utils

mirai-core/src/commonMain/kotlin/net.mamoe.mirai/utils/channels.kt

@@ -0,0 +1,114 @@
+/*
+ * 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
+ */
+
+
+@file:JvmName("Utils")
+@file:JvmMultifileClass
+
+package net.mamoe.mirai.utils
+
+
+import io.ktor.utils.io.ByteReadChannel
+import io.ktor.utils.io.readAvailable
+import kotlinx.coroutines.io.close
+import kotlinx.io.OutputStream
+import kotlinx.io.core.Output
+import kotlinx.io.pool.useInstance
+import net.mamoe.mirai.utils.io.ByteArrayPool
+import kotlin.jvm.JvmMultifileClass
+import kotlin.jvm.JvmName
+
+
+/**
+ * 从接收者管道读取所有数据并写入 [dst]. 不会关闭 [dst]
+ */
+suspend fun ByteReadChannel.copyTo(dst: OutputStream) {
+    ByteArrayPool.useInstance {
+        do {
+            val size = this.readAvailable(it)
+            dst.write(it, 0, size)
+        } while (size != 0)
+    }
+}
+
+/**
+ * 从接收者管道读取所有数据并写入 [dst]. 不会关闭 [dst]
+ */
+suspend fun ByteReadChannel.copyTo(dst: Output) {
+    ByteArrayPool.useInstance {
+        do {
+            val size = this.readAvailable(it)
+            dst.writeFully(it, 0, size)
+        } while (size != 0)
+    }
+}
+
+/**
+ * 从接收者管道读取所有数据并写入 [dst]. 不会关闭 [dst]
+ */
+suspend fun ByteReadChannel.copyTo(dst: kotlinx.coroutines.io.ByteWriteChannel) {
+    ByteArrayPool.useInstance {
+        do {
+            val size = this.readAvailable(it)
+            dst.writeFully(it, 0, size)
+        } while (size != 0)
+    }
+}
+
+
+// copyAndClose
+
+
+/**
+ * 从接收者管道读取所有数据并写入 [dst], 最终关闭 [dst]
+ */
+suspend fun ByteReadChannel.copyAndClose(dst: OutputStream) {
+    try {
+        ByteArrayPool.useInstance {
+            do {
+                val size = this.readAvailable(it)
+                dst.write(it, 0, size)
+            } while (size != 0)
+        }
+    } finally {
+        dst.close()
+    }
+}
+
+/**
+ * 从接收者管道读取所有数据并写入 [dst], 最终关闭 [dst]
+ */
+suspend fun ByteReadChannel.copyAndClose(dst: Output) {
+    try {
+        ByteArrayPool.useInstance {
+            do {
+                val size = this.readAvailable(it)
+                dst.writeFully(it, 0, size)
+            } while (size != 0)
+        }
+    } finally {
+        dst.close()
+    }
+}
+
+/**
+ * 从接收者管道读取所有数据并写入 [dst], 最终关闭 [dst]
+ */
+suspend fun ByteReadChannel.copyAndClose(dst: kotlinx.coroutines.io.ByteWriteChannel) {
+    try {
+        ByteArrayPool.useInstance {
+            do {
+                val size = this.readAvailable(it)
+                dst.writeFully(it, 0, size)
+            } while (size != 0)
+        }
+    } finally {
+        dst.close()
+    }
+}