Struct LocalReader

Source

pub struct LocalReader<T: 'static> { /* private fields */ }

Expand description

A reader thread’s local version state.

Each reader thread should create exactly one LocalReader via SwmrCell::local(). It is !Sync (due to Cell) and must be stored per-thread.

The LocalReader is used to:

Pin the thread to the current version via pin().
Obtain a PinGuard that protects access to values and can be dereferenced.

Thread Safety: LocalReader is not Sync and must be used by only one thread.

读者线程的本地版本状态。每个读者线程应该通过 SwmrCell::local() 创建恰好一个 LocalReader。它是 !Sync 的（因为 Cell），必须在每个线程中存储。 LocalReader 用于：

通过 pin() 将线程钉住到当前版本。
获取保护对值访问的 PinGuard，可以解引用来读取值。 线程安全性：LocalReader 不是 Sync 的，必须仅由一个线程使用。

Implementations§

Source §

impl<T: 'static> LocalReader<T>

Source

pub fn pin(&self) -> PinGuard<'_, T>

Pin this thread to the current version.

Returns a PinGuard that keeps the thread pinned for its lifetime. The guard can be dereferenced to access the current value.

Reentrancy: This method is reentrant. Multiple calls can be nested, and the thread remains pinned until all returned guards are dropped. You can also clone a guard to create additional references: let guard2 = guard1.clone();

Example:

let local = cell.local();
let guard1 = local.pin();
let value = *guard1;  // Dereference to read
let guard2 = local.pin();  // Reentrant call
let guard3 = guard1.clone();     // Clone for nested scope
// Thread remains pinned until all three guards are dropped

While pinned, the thread is considered “active” at a particular version, and the garbage collector will not reclaim data from that version.

将此线程钉住到当前版本。

返回一个 PinGuard，在其生命周期内保持线程被钉住。可以解引用该守卫来访问当前值。

可重入性：此方法是可重入的。多个调用可以嵌套，线程在所有返回的守卫被 drop 之前保持被钉住。你也可以克隆一个守卫来创建额外的引用：let guard2 = guard1.clone();

示例：

let local = cell.local();
let guard1 = local.pin();
let value = *guard1;  // 解引用来读取
let guard2 = local.pin();  // 可重入调用
let guard3 = guard1.clone();     // 克隆用于嵌套作用域
// 线程保持被钉住直到所有三个守卫被 drop

当被钉住时，线程被认为在特定版本“活跃“，垃圾回收器不会回收该版本的数据。