feat: 新增 SharedBuffer 共享字节缓冲与核账目

Cargo.lock

@@ -1160,7 +1160,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_builtins"
-version = "0.8.79"
+version = "0.8.80"
 dependencies = [
  "chrono",
  "fast-float",
@@ -1185,7 +1185,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_bytecode"
-version = "0.8.79"
+version = "0.8.80"
 dependencies = [
  "num-bigint",
  "oxide_log",
@@ -1193,7 +1193,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_cfg"
-version = "0.8.79"
+version = "0.8.80"
 dependencies = [
  "oxide_bytecode",
  "oxide_emit",
@@ -1204,7 +1204,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_cli"
-version = "0.8.79"
+version = "0.8.80"
 dependencies = [
  "ansi_term",
  "bumpalo",
@@ -1226,7 +1226,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_code_cache"
-version = "0.8.79"
+version = "0.8.80"
 dependencies = [
  "lru",
  "oxide_bytecode",
@@ -1235,7 +1235,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_compiler"
-version = "0.8.79"
+version = "0.8.80"
 dependencies = [
  "oxide_bytecode",
  "oxide_cfg",
@@ -1255,7 +1255,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_dce"
-version = "0.8.79"
+version = "0.8.80"
 dependencies = [
  "oxide_bytecode",
  "oxide_cfg",
@@ -1269,7 +1269,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_emit"
-version = "0.8.79"
+version = "0.8.80"
 dependencies = [
  "num-bigint",
  "oxc_allocator",
@@ -1284,7 +1284,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_engine"
-version = "0.8.79"
+version = "0.8.80"
 dependencies = [
  "oxide_bytecode",
  "oxide_compiler",
@@ -1296,7 +1296,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_ir"
-version = "0.8.79"
+version = "0.8.80"
 dependencies = [
  "oxide_bytecode",
  "oxide_log",
@@ -1305,7 +1305,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_kernel"
-version = "0.8.79"
+version = "0.8.80"
 dependencies = [
  "bumpalo",
  "dashmap",
@@ -1319,7 +1319,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_liveness"
-version = "0.8.79"
+version = "0.8.80"
 dependencies = [
  "oxide_bytecode",
  "oxide_cfg",
@@ -1331,7 +1331,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_log"
-version = "0.8.79"
+version = "0.8.80"
 dependencies = [
  "tracing",
  "tracing-appender",
@@ -1340,7 +1340,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_parser"
-version = "0.8.79"
+version = "0.8.80"
 dependencies = [
  "oxc_allocator",
  "oxc_ast",
@@ -1355,7 +1355,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_regalloc"
-version = "0.8.79"
+version = "0.8.80"
 dependencies = [
  "oxide_bytecode",
  "oxide_cfg",
@@ -1371,7 +1371,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_runtime_api"
-version = "0.8.79"
+version = "0.8.80"
 dependencies = [
  "num-bigint",
  "num-traits",
@@ -1383,7 +1383,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_test262"
-version = "0.8.79"
+version = "0.8.80"
 dependencies = [
  "oxide_bytecode",
  "oxide_compiler",
@@ -1401,7 +1401,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_types"
-version = "0.8.79"
+version = "0.8.80"
 dependencies = [
  "bumpalo",
  "dashmap",
@@ -1414,7 +1414,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_vm"
-version = "0.8.79"
+version = "0.8.80"
 dependencies = [
  "bumpalo",
  "chrono",

Cargo.toml

@@ -23,7 +23,7 @@ members = [
 ]
 
 [workspace.package]
-version = "0.8.79"
+version = "0.8.80"
 edition = "2021"
 license = "MIT"
 rust-version = "1.80"

crates/oxide_kernel/src/kernel/core.rs

@@ -36,6 +36,9 @@ pub struct KernelCore {
     /// 内创建满 512 个 Vm 前重建 kernel（重建即计数器归零）；test262 runner
     /// 经 kernel_batch 缺省值（不超 512）满足该约束。
     realm_counter: AtomicU32,
+    /// 共享字节缓冲账目：存活 `SharedBuffer` 的预分配真实上限之和。
+    /// `SharedBuffer` 构造加、`Drop` 减（同值），供宿主读取共享层内存占用。
+    shared_buffer_bytes: AtomicUsize,
 }
 
 impl KernelCore {
@@ -66,6 +69,7 @@ impl KernelCore {
             prop_forge,
             active_vms: AtomicUsize::new(0),
             realm_counter: AtomicU32::new(0),
+            shared_buffer_bytes: AtomicUsize::new(0),
         });
         kernel_info!("KernelCore initialized: max_cached_modules={}, min_pool={}", max_cached, min_pool);
         core
@@ -196,6 +200,21 @@ impl KernelCore {
         self.active_vms.load(Ordering::Relaxed)
     }
 
+    /// 读取存活共享字节缓冲的预分配真实上限之和（字节）。
+    pub fn shared_buffer_bytes(&self) -> usize {
+        self.shared_buffer_bytes.load(Ordering::Relaxed)
+    }
+
+    /// 共享字节缓冲账目加账（`SharedBuffer` 构造调用；单位是预分配真实上限）。
+    pub(crate) fn shared_buffer_bytes_add(&self, bytes: usize) {
+        self.shared_buffer_bytes.fetch_add(bytes, Ordering::Relaxed);
+    }
+
+    /// 共享字节缓冲账目减账（`SharedBuffer` 析构调用；单位是预分配真实上限）。
+    pub(crate) fn shared_buffer_bytes_sub(&self, bytes: usize) {
+        self.shared_buffer_bytes.fetch_sub(bytes, Ordering::Relaxed);
+    }
+
     /// 分配一个 realm 编号：取计数器当前值后自增，进程内单调递增。
     ///
     /// 首个 realm 编号为 0（与旧符号编码一致），供 `Realm` 构造时固化。

crates/oxide_kernel/src/lib.rs

@@ -17,6 +17,8 @@ pub mod kernel_log;
 pub mod prop_forge;
 /// hidden class（shape）共享存储：把对象结构映射为整数 id。
 pub mod shape_forge;
+/// 共享字节缓冲：SharedArrayBuffer 的跨线程共享存储（预分配至真实上限，活长原子推进）。
+pub mod shared_buffer;
 
 /// kernel 对外的三个核心类型：配置、共享核心、会话。
 pub use kernel::{KernelConfig, KernelCore, KernelSession};
@@ -24,3 +26,5 @@ pub use kernel::{KernelConfig, KernelCore, KernelSession};
 pub use oxide_types::string_forge;
 /// 模块命名空间再导出的绑定身份哨兵（本体在 `oxide_types`，此处再导出）。
 pub use oxide_types::MODULE_NAMESPACE_BINDING;
+/// 跨线程共享字节缓冲（SharedArrayBuffer 的共享存储）。
+pub use shared_buffer::SharedBuffer;

crates/oxide_kernel/src/shared_buffer.rs

@@ -0,0 +1,247 @@
+//! 共享字节缓冲：SharedArrayBuffer 的跨线程共享存储。
+//!
+//! 关键约定：
+//! - 字节区一次性预分配至真实上限并零填充，此后不再重分配；`grow` 只推进活长，O(1)。
+//! - `write_range` 经 `&self` 裸写（字节区归本结构独占，类型不暴露 `&mut [u8]`），多线程并发写安全。
+//! - 账目单位是预分配真实上限：构造时计入 `KernelCore::shared_buffer_bytes`，`Drop` 减同值。
+
+use std::sync::atomic::{AtomicUsize, Ordering};
+use std::sync::Arc;
+
+use crate::KernelCore;
+
+/// 共享字节缓冲操作的越界错误。
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum SharedBufferError {
+    /// 写范围超出活长（offset + data 长度 > len）。
+    OutOfRange,
+}
+
+/// 跨线程共享字节缓冲：预分配至真实上限，活长经原子推进。
+///
+/// 全部字段 `Send + Sync`，可经 `Arc` 跨线程共享；账目入口是结构持有的
+/// `Arc<KernelCore>`，`Drop` 时从核的 `shared_buffer_bytes` 减预分配真实上限。
+pub struct SharedBuffer {
+    /// 共享字节区，预分配至真实上限并零填充。
+    bytes: Arc<Vec<u8>>,
+    /// 活字节长（growable 经原子推进）。
+    length: AtomicUsize,
+    /// 预分配真实上限。
+    max_length: usize,
+    /// 账目入口。
+    core: Arc<KernelCore>,
+}
+
+impl SharedBuffer {
+    /// 定长构造：字节序列即活内容，上限即字节序列长度。
+    ///
+    /// # 副作用
+    /// - 核的 `shared_buffer_bytes` 加字节序列长度（真实上限）。
+    pub fn new(core: Arc<KernelCore>, bytes: Vec<u8>) -> Self {
+        let bytes = Arc::new(bytes);
+        let len = bytes.len();
+        core.shared_buffer_bytes_add(len);
+        Self {
+            bytes,
+            length: AtomicUsize::new(len),
+            max_length: len,
+            core,
+        }
+    }
+
+    /// 可增长构造：预分配至 `max_len` 并零填充，初始活长 `initial_len`。
+    ///
+    /// # 边界与前提
+    /// - `initial_len` 不得超过 `max_len`（debug 构建 fail-fast）。
+    ///
+    /// # 副作用
+    /// - 核的 `shared_buffer_bytes` 加 `max_len`（真实上限），而非 `initial_len`。
+    pub fn new_growable(core: Arc<KernelCore>, initial_len: usize, max_len: usize) -> Self {
+        debug_assert!(initial_len <= max_len, "initial_len must not exceed max_len");
+        let bytes = Arc::new(vec![0u8; max_len]);
+        core.shared_buffer_bytes_add(max_len);
+        Self {
+            bytes,
+            length: AtomicUsize::new(initial_len),
+            max_length: max_len,
+            core,
+        }
+    }
+
+    /// 读取当前活字节长。
+    pub fn len(&self) -> usize {
+        self.length.load(Ordering::SeqCst)
+    }
+
+    /// 判断活区是否为空。
+    pub fn is_empty(&self) -> bool {
+        self.len() == 0
+    }
+
+    /// 读取预分配真实上限。
+    pub fn max_len(&self) -> usize {
+        self.max_length
+    }
+
+    /// 活长区只读切片。
+    pub fn as_slice(&self) -> &[u8] {
+        &self.bytes[..self.len()]
+    }
+
+    /// 把 `data` 写入活长区 `offset` 起（经 `&self` 裸写）。
+    ///
+    /// # 边界与前提
+    /// - `offset + data.len()` 超过活长时返回 `OutOfRange`，不做任何写入；
+    /// - 写入不改变活长。
+    ///
+    /// # 注意事项
+    /// - 字节区归本结构独占且类型不暴露 `&mut [u8]`，经 `&self` 裸写不构成别名；
+    ///   不得新增 `bytes_mut` 一类方法，否则该前提失效。
+    pub fn write_range(&self, offset: usize, data: &[u8]) -> Result<(), SharedBufferError> {
+        let end = offset.checked_add(data.len()).ok_or(SharedBufferError::OutOfRange)?;
+        if end > self.len() {
+            return Err(SharedBufferError::OutOfRange);
+        }
+        unsafe {
+            // 字节区归本结构独占，裸写目标即其内部可变区。
+            let dest = self.bytes.as_ptr().add(offset) as *mut u8;
+            std::ptr::copy_nonoverlapping(data.as_ptr(), dest, data.len());
+        }
+        Ok(())
+    }
+
+    /// 把活长推进到 `new_len`（只增不缩），返回操作后活长。
+    ///
+    /// # 边界与前提
+    /// - 缩长（`new_len` 不大于当前活长）与超上限（`new_len` 大于 `max_len`）均被拒绝，
+    ///   返回当前活长；
+    /// - 字节区已预分配，推进只改原子计数，O(1)。
+    ///
+    /// # 副作用
+    /// - 经 CAS 循环推进 `length`；并发调用各自至多推进一次。
+    pub fn grow(&self, new_len: usize) -> usize {
+        let mut cur = self.length.load(Ordering::SeqCst);
+        loop {
+            // 缩长与超上限统一拒绝，返回当前活长。
+            if new_len <= cur || new_len > self.max_length {
+                return cur;
+            }
+            match self
+                .length
+                .compare_exchange_weak(cur, new_len, Ordering::SeqCst, Ordering::SeqCst)
+            {
+                Ok(_) => return new_len,
+                Err(next) => cur = next,
+            }
+        }
+    }
+}
+
+impl Drop for SharedBuffer {
+    fn drop(&mut self) {
+        // 账目单位与构造时加账一致：预分配真实上限。
+        self.core.shared_buffer_bytes_sub(self.bytes.len());
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::KernelConfig;
+
+    fn new_core() -> Arc<KernelCore> {
+        KernelCore::new(KernelConfig::minimal())
+    }
+
+    #[test]
+    fn shared_buffer_is_send_sync() {
+        fn assert_send_sync<T: Send + Sync>() {}
+        assert_send_sync::<SharedBuffer>();
+    }
+
+    #[test]
+    fn new_fixed_size_len_and_accounting() {
+        let core = new_core();
+        let buf = SharedBuffer::new(core.clone(), vec![1, 2, 3, 4]);
+        assert_eq!(buf.len(), 4);
+        assert_eq!(buf.max_len(), 4);
+        assert_eq!(buf.as_slice(), &[1, 2, 3, 4]);
+        assert_eq!(core.shared_buffer_bytes(), 4);
+    }
+
+    #[test]
+    fn new_growable_preallocates_to_max() {
+        let core = new_core();
+        let buf = SharedBuffer::new_growable(core.clone(), 2, 8);
+        assert_eq!(buf.len(), 2);
+        assert_eq!(buf.max_len(), 8);
+        assert_eq!(buf.as_slice(), &[0, 0]);
+        // 账目单位是预分配真实上限，而非初始活长。
+        assert_eq!(core.shared_buffer_bytes(), 8);
+    }
+
+    #[test]
+    fn write_range_updates_live_region() {
+        let core = new_core();
+        let buf = SharedBuffer::new(core, vec![0u8; 8]);
+        buf.write_range(2, &[9, 8, 7]).unwrap();
+        assert_eq!(buf.as_slice(), &[0, 0, 9, 8, 7, 0, 0, 0]);
+        assert_eq!(buf.len(), 8);
+    }
+
+    #[test]
+    fn write_range_rejects_out_of_range() {
+        let core = new_core();
+        let buf = SharedBuffer::new(core, vec![0u8; 4]);
+        assert_eq!(buf.write_range(3, &[1, 2]), Err(SharedBufferError::OutOfRange));
+        // offset 溢出加法同样按越界处理。
+        assert_eq!(buf.write_range(usize::MAX, &[1]), Err(SharedBufferError::OutOfRange));
+        // 拒绝时活长不变。
+        assert_eq!(buf.len(), 4);
+    }
+
+    #[test]
+    fn grow_only_increases_and_caps_at_max() {
+        let core = new_core();
+        let buf = SharedBuffer::new_growable(core, 2, 8);
+        assert_eq!(buf.grow(5), 5);
+        assert_eq!(buf.as_slice(), &[0, 0, 0, 0, 0]);
+        // 缩长被拒绝，活长不变。
+        assert_eq!(buf.grow(3), 5);
+        // 超上限被拒绝，活长不变。
+        assert_eq!(buf.grow(9), 5);
+        // 恰好到上限成功。
+        assert_eq!(buf.grow(8), 8);
+    }
+
+    #[test]
+    fn drop_returns_accounting_to_zero() {
+        let core = new_core();
+        {
+            let fixed = SharedBuffer::new(core.clone(), vec![0u8; 4]);
+            // 作用域末隐式析构，验证减账归零。
+            let _growable = SharedBuffer::new_growable(core.clone(), 0, 16);
+            assert_eq!(core.shared_buffer_bytes(), 20);
+            drop(fixed);
+            assert_eq!(core.shared_buffer_bytes(), 16);
+        }
+        assert_eq!(core.shared_buffer_bytes(), 0);
+    }
+
+    #[test]
+    fn arc_shared_across_threads() {
+        let core = new_core();
+        let buf = Arc::new(SharedBuffer::new_growable(core, 0, 16));
+        let child = {
+            let buf = Arc::clone(&buf);
+            std::thread::spawn(move || {
+                buf.grow(8);
+                buf.write_range(4, &[0xAB, 0xCD]).unwrap();
+                buf.len()
+            })
+        };
+        let len = child.join().unwrap();
+        assert_eq!(len, 8);
+        assert_eq!(buf.as_slice(), &[0, 0, 0, 0, 0xAB, 0xCD, 0, 0]);
+    }
+}