amberjs 1.16.1

// 异步零拷贝传输
// 实现高性能的异步零拷贝数据传输

use std::collections::HashMap;
use std::sync::{Arc, Mutex, RwLock};

use super::{NetworkConfig, NetworkStats};
use memmap2::{Mmap, MmapOptions};
use std::time::{Duration, Instant};
use std::task::Poll;
use std::task::Context;
use std::pin::Pin;
/// 零拷贝错误
#[derive(Debug, thiserror::Error)]
pub enum ZeroCopyError {
    #[error("I/O 错误: {0}")]
    Io(#[from] std::io::Error),
    #[error("内存映射错误: {0}")]
    Mmap(String),
    #[error("传输被取消")]
    Cancelled,
    #[error("超时")]
    Timeout,
}
/// 传输请求
#[derive(Debug, Clone)]
pub struct TransferRequest {
    pub id: u64,
    pub source: Vec<u8>,
    pub destination: String,
    pub priority: u8,
    pub timeout_ms: u64,
}
/// 传输统计
#[derive(Debug, Clone)]
pub struct TransferStats {
    pub total_transfers: u64,
    pub successful_transfers: u64,
    pub failed_transfers: u64,
    pub total_bytes_transferred: u64,
    pub average_transfer_time_ns: u64,
    pub zero_copy_ratio: f64,
}
/// 零拷贝 Future
pub struct ZeroCopyFuture {
    id: u64,
    receiver: oneshot::Receiver<Result<u64, ZeroCopyError>>,
}
impl ZeroCopyFuture {
    pub fn new(id: u64, receiver: oneshot::Receiver<Result<u64, ZeroCopyError>>) -> Self {
        Self { id, receiver }
    }
}
impl Future for ZeroCopyFuture {
    type Output = Result<u64, ZeroCopyError>;
    fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
        match Pin::new(&mut self.receiver).poll(cx) {
            Poll::Ready(result) => Poll::Ready(result.unwrap_or(Err(ZeroCopyError::Cancelled))),
            Poll::Pending => Poll::Pending,
        }
    }
}
/// 异步零拷贝引擎
pub struct AsyncZeroCopy {
    config: NetworkConfig,
    stats: Arc<RwLock<TransferStats>>,
    active_transfers: Arc<RwLock<std::collections::HashMap<u64, TransferRequest>>>,
    transfer_counter: Arc<RwLock<u64>>,
}
impl AsyncZeroCopy {
    /// 创建新的异步零拷贝引擎
    pub fn new(config: NetworkConfig) -> Self {
        Self {
            stats: Arc::new(Mutex::new(TransferStats {
                total_transfers: 0,
                successful_transfers: 0,
                failed_transfers: 0,
                total_bytes_transferred: 0,
                average_transfer_time_ns: 0,
                zero_copy_ratio: 0.0,
            })),
            active_transfers: Arc::new(Mutex::new(std::collections::HashMap::new())),
            transfer_counter: Arc::new(Mutex::new(0)),
            config,
        }
    }
    /// 启动异步零拷贝传输
    pub async fn transfer(&self, request: TransferRequest) -> Result<ZeroCopyFuture, ZeroCopyError> {
        let id: _ = {
            let mut counter = self.transfer_counter.write().await;
            *counter += 1;
            *counter
        };
        let (sender, receiver) = oneshot::channel();
        let request_with_id: _ = TransferRequest { id, ..request };
        // 记录活跃传输
        {
            let mut active = self.active_transfers.write().await;
            active.insert(id, request_with_id.clone());
        }
        // 异步执行传输
        let stats: _ = Arc::clone(&self.stats);
        let active_transfers: _ = Arc::clone(&self.active_transfers);
        tokio::spawn(async move {
            let start: _ = std::time::Instant::now();
            let result: _ = Self::perform_transfer(request_with_id).await;
            // 更新统计
            let mut stats_guard = stats.write().await;
            stats_guard.total_transfers += 1;
            match &result {
                Ok(bytes) => {
                    stats_guard.successful_transfers += 1;
                    stats_guard.total_bytes_transferred += *bytes;
                    stats_guard.average_transfer_time_ns =
                        (stats_guard.average_transfer_time_ns + start.elapsed().as_nanos() as u64) / 2;
                    stats_guard.zero_copy_ratio = stats_guard.successful_transfers as f64
                        / stats_guard.total_transfers as f64;
                }
                Err(_) => {
                    stats_guard.failed_transfers += 1;
                }
            }
            // 移除活跃传输
            active_transfers.write().await.remove(&id);
            let _: _ = sender.send(result);
        });
        Ok(ZeroCopyFuture::new(id, receiver))
    }
    /// 执行实际的零拷贝传输
    async fn perform_transfer(request: TransferRequest) -> Result<u64, ZeroCopyError> {
        // 创建内存映射
        let mmap: _ = Self::create_memory_map(&request.source)?;
        // 执行传输（简化实现）
        // 实际实现中这里会使用 sendfile 或其他零拷贝机制
        let bytes_sent: _ = request.source.len();
        // 模拟传输延迟
        tokio::time::sleep(Duration::from_micros(100)).await;
        Ok(bytes_sent as u64)
    }
    /// 创建内存映射
    fn create_memory_map(data: &[u8]) -> Result<Mmap, ZeroCopyError> {
        // 创建临时文件
        let temp_file: _ = std::env::temp_dir()
            .join(format!("amberjs_async_zero_copy_{}", std::process::id()));
        let file: _ = std::fs::OpenOptions::new()
            .read(true)
            .write(true)
            .create(true)
            .open(&temp_file)?;
        // 设置文件大小
        file.set_len(data.len() as u64)?;
        // 创建内存映射
        unsafe {
            let mmap: _ = MmapOptions::new()
                .map(&file)
                .map_err(|e| ZeroCopyError::Mmap(e.to_string()))?;
            // 复制数据到映射内存
            std::ptr::copy_nonoverlapping(
                data.as_ptr(),
                mmap.as_ptr() as *mut u8,
                data.len()
            );
            Ok(mmap)
        }
    }
    /// 取消传输
    pub async fn cancel_transfer(&self, id: u64) -> Result<(), ZeroCopyError> {
        let mut active = self.active_transfers.write().await;
        active.remove(&id);
        Ok(())
    }
    /// 获取统计信息
    pub async fn get_stats(&self) -> TransferStats {
        self.stats.read().await.clone()
    }
    /// 获取活跃传输数
    pub async fn get_active_transfers_count(&self) -> usize {
        self.active_transfers.read().await.len()
    }
}
impl Drop for AsyncZeroCopy {
    fn drop(&mut self) {
        // 清理临时文件
        let temp_file: _ = std::env::temp_dir()
            .join(format!("amberjs_async_zero_copy_{}", std::process::id()));
        let _: _ = std::fs::remove_file(temp_file);
    }
}