Lifeguard

https://github.com/zslayton/lifeguard
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Lifeguard is an object pool manager in Rust that implements a builder API to customize pool size,...
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License:MIT
Update:2 months ago
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### Manage Pooled Values with Lifeguard

Source: https://github.com/zslayton/lifeguard/blob/master/README.md

Demonstrates basic pool usage where values are automatically returned to the pool when they go out of scope.

```rust
extern crate lifeguard;
use lifeguard::*;

fn main() {
    let pool : Pool<String> = pool().with(StartingSize(10)).build();
    {
        let string = pool.new_from("Hello, World!"); // Remove a value from the pool
        assert_eq!(9, pool.size());
    } // Values that have gone out of scope are automatically moved back into the pool.
    assert_eq!(10, pool.size());
}
```

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### Configure Pool with Builder API

Source: https://github.com/zslayton/lifeguard/blob/master/README.md

Uses the builder pattern to customize pool size, growth limits, and object supply logic.

```rust
extern crate lifeguard;
use lifeguard::*;

fn main() {
 let pool : Pool<String> = pool()
   // The pool will allocate 128 values for immediate use. More will be allocated on demand.
   .with(StartingSize(128))
   // The pool will only grow up to 4096 values. Further values will be dropped.
   .with(MaxSize(4096))
   // The pool will use this closure (or other object implementing Supply<T>) to allocate
   .with(Supplier(|| String::with_capacity(1024)))
   .build();
  // ...
}
```

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### Manually Attach Values to the Pool

Source: https://github.com/zslayton/lifeguard/blob/master/README.md

Demonstrates how to manually return a detached value to the pool.

```rust
extern crate lifeguard;
use lifeguard::*;

fn main() {
    let pool : Pool<String> = pool().with(StartingSize(10)).build();
    {
        let string : String = pool.detached(); // An unwrapped String, detached from the Pool
        assert_eq!(9, pool.size());
        let rstring : Recycled<String> = pool.attach(string); // The String is attached to the pool again
        assert_eq!(9, pool.size()); // but it is still checked out from the pool
    } // rstring goes out of scope and is added back to the pool
    assert_eq!(10, pool.size());
}
```

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### Access and Mutate Pooled Values

Source: https://github.com/zslayton/lifeguard/blob/master/README.md

Shows how to dereference pooled values to access or mutate their contents.

```rust
extern crate lifeguard;
use lifeguard::*;

fn main() {
    let pool : Pool<String> = pool().with(StartingSize(10)).build();
    let mut string = pool.new_from("cat");
    string.push_str("s love eating mice"); //string.as_mut() also works
    assert_eq!("cats love eating mice", *string);
}
```

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### Detach Values from the Pool

Source: https://github.com/zslayton/lifeguard/blob/master/README.md

Illustrates how to unwrap a value from the pool, preventing it from being returned automatically.

```rust
extern crate lifeguard;
use lifeguard::*;

fn main() {
    let pool : Pool<String> = pool().with(StartingSize(10)).build();
    {
        let string : String = pool.new().detach();
    } // The String goes out of scope and is dropped; it is not returned to the pool
    assert_eq!(9, pool.size());
}
```
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