// kotlinx.coroutines.scheduling.DefaultScheduler源码简化
internal object DefaultScheduler : Scheduler() {private const val DEFAULT_PARALLELISM = 64override val parallelism: Int get() = kotlin.math.min(Runtime.getRuntime().availableProcessors(), DEFAULT_PARALLELISM)// 使用ForkJoinPool实现工作窃取算法private val pool = ForkJoinPool(parallelism,{ pool ->val worker = ForkJoinPool.ManagedWorkerThread(pool)worker.name = "DefaultDispatcher-worker-${worker.poolIndex}"worker.isDaemon = trueworker},null,true)// 任务调度实现override fun dispatch(context: CoroutineContext, block: Runnable) {pool.execute(block)}
}

// kotlinx.coroutines.scheduling.IOcheduler源码简化
internal object IO : CoroutineDispatcher() {private const val MAX_POOL_SIZE = 64// 使用带工作窃取的线程池private val scheduler = DefaultScheduler.IOoverride fun dispatch(context: CoroutineContext, block: Runnable) {scheduler.dispatch(context, block)}
}// DefaultScheduler.IO实现
internal val IO: Scheduler = createScheduler(corePoolSize = 64,maxPoolSize = 64,keepAliveTime = 60,schedulerName = "IO"
)

// kotlinx.coroutines.withContext源码简化
public suspend fun <T> withContext(context: CoroutineContext,block: suspend CoroutineScope.() -> T
): T {// 检查是否需要切换上下文val newContext = coroutineContext + contextif (newContext === coroutineContext) {return block() // 无需切换，直接执行}// 创建新的协程作用域return suspendCoroutineUninterceptedOrReturn sc@ { uCont ->val coroutine = ScopeCoroutine(newContext, uCont)coroutine.startUndispatchedOrReturn(coroutine, block)}
}// ScopeCoroutine实现
private class ScopeCoroutine<in T>(context: CoroutineContext,private val uCont: Continuation<T>
) : AbstractCoroutine<T>(context, true) {override fun handleJobException(exception: Throwable): Boolean =uCont.context[Job]?.handleJobException(exception) ?: falseoverride fun resumeWith(result: Result<T>) {uCont.resumeWith(result)}
}

// kotlinx.coroutines.CoroutineStart源码
public enum class CoroutineStart {/** 立即调度协程执行 */DEFAULT,/** 延迟启动，直到调用start()或await() */LAZY,/** 立即调度，但在开始执行前不能被取消 */ATOMIC,/** 立即在当前线程执行，直到第一个挂起点 */UNDISPATCHED;// 启动协程的方法public operator fun <T> invoke(coroutine: CoroutineScope,block: suspend CoroutineScope.() -> T,completion: Continuation<T>): Unit = when (this) {DEFAULT -> coroutine.startCoroutineCancellable(block, completion)ATOMIC -> coroutine.startCoroutine(block, completion)UNDISPATCHED -> coroutine.startCoroutineUndispatched(block, completion)LAZY -> Unit // 延迟启动，不执行任何操作}
}

// kotlinx.coroutines.coroutineScope源码简化
public suspend fun <R> coroutineScope(block: suspend CoroutineScope.() -> R): R {// 创建新的协程作用域return suspendCoroutineUninterceptedOrReturn { uCont ->val scope = ScopeCoroutine(uCont.context, uCont)// 启动协程scope.startUndispatchedOrReturn(scope, block)}
}// ScopeCoroutine的关键实现
private class ScopeCoroutine<in T>(context: CoroutineContext,private val uCont: Continuation<T>
) : AbstractCoroutine<T>(context, true) {// 等待所有子协程完成override fun afterCompletion(state: Any?) {// 检查所有子协程是否完成if (children != null) {// 等待未完成的子协程children!!.joinAll()}// 完成协程uCont.resumeWith(Result.success(Unit))}
}

// kotlinx.coroutines.Job源码简化
public interface Job : CoroutineContext.Element {// 取消协程并传播异常public fun cancel(cause: CancellationException? = null): Boolean// 处理协程异常public fun handleJobException(exception: Throwable): Boolean
}// AbstractCoroutine的异常处理实现
internal abstract class AbstractCoroutine<in T>(context: CoroutineContext,active: Boolean
) : JobSupport(active), Job, Continuation<T>, CoroutineScope {// 处理协程完成结果override fun resumeWith(result: Result<T>) {try {// 处理正常完成或异常val state = makeCompletingOnce(result.toState())afterResume(state)} catch (e: Throwable) {handleCoroutineException(context, e)}}// 处理协程异常protected open fun handleCoroutineException(context: CoroutineContext, exception: Throwable) {context[CoroutineExceptionHandler]?.let { handler ->try {handler.handleException(context, exception)} catch (t: Throwable) {// 处理异常处理器抛出的异常handleCoroutineExceptionImpl(context, handlerException(exception, t))}return}// 如果没有处理器，使用默认实现handleCoroutineExceptionImpl(context, exception)}
}

// kotlinx.coroutines.io包中的非阻塞I/O示例
public suspend fun Reader.readText(): String {return buildString {val buffer = CharArray(8192)var read: Intwhile (true) {// 挂起协程，不阻塞线程read = readSuspend(buffer)if (read <= 0) breakappend(buffer, 0, read)}}
}// readSuspend的实现（简化）
private suspend fun Reader.readSuspend(buffer: CharArray): Int {return withContext(Dispatchers.IO) {// 在IO调度器中执行阻塞操作read(buffer)}
}

// kotlin.coroutines.jvm.internal.BaseContinuationImpl源码简化
internal abstract class BaseContinuationImpl(public val completion: Continuation<Any?>?
) : Continuation<Any?>, CoroutineStackFrame {// 协程状态private var label: Int = 0// 恢复协程执行public final override fun resumeWith(result: Result<Any?>) {var current = thisvar param = resultwhile (true) {// 根据label值恢复到特定挂起点val outcome = invokeSuspend(param)if (outcome === COROUTINE_SUSPENDED) return// 处理协程结果val completion = current.completion!!if (completion is BaseContinuationImpl) {current = completionparam = Result.success(outcome)} else {completion.resumeWith(Result.success(outcome))return}}}// 由编译器生成的协程体实现protected abstract fun invokeSuspend(result: Result<Any?>): Any?
}

// kotlinx.coroutines.flow.Flow源码简化
public interface Flow<out T> {// 收集Flow中的元素public suspend fun collect(collector: FlowCollector<T>)
}// Flow操作符实现示例
public fun <T> Flow<T>.filter(predicate: suspend (T) -> Boolean): Flow<T> = flow {collect { value ->if (predicate(value)) {emit(value) // 挂起点，可能切换线程}}
}// flow构建器实现
public fun <T> flow(block: suspend FlowCollector<T>.() -> Unit): Flow<T> = SafeFlow(block)private class SafeFlow<T>(private val block: suspend FlowCollector<T>.() -> Unit) : Flow<T> {override suspend fun collect(collector: FlowCollector<T>) {// 创建安全的收集器val safeCollector = SafeCollector(collector, coroutineContext)try {// 执行流构建块safeCollector.block()} finally {// 确保资源释放safeCollector.releaseIntercepted()}}
}

// kotlinx.coroutines.DebugKt源码简化
public object Debug {// 是否启用调试模式public var isDebugging: Boolean = falseprivate set// 初始化调试模式internal fun init() {// 检查是否设置了调试系统属性isDebugging = System.getProperty("kotlinx.coroutines.debug") != nullif (isDebugging) {// 注册调试钩子installDebugHook()}}// 获取协程堆栈信息public fun getCoroutineStackTrace(coroutine: Job): String? {if (!isDebugging) return null// 获取协程的调试信息return (coroutine as? DebugCoroutine)?.getStackTraceAsString()}
}// DebugCoroutine接口定义
internal interface DebugCoroutine : CoroutineStackFrame {// 获取协程堆栈信息fun getStackTraceAsString(): String
}