# queue-file
[![Crate](https://img.shields.io/crates/v/queue-file.svg)](https://crates.io/crates/queue-file)
[![API](https://docs.rs/queue-file/badge.svg)](https://docs.rs/queue-file)
queue-file is a lightning-fast, transactional, file-based FIFO.
Addition and removal from an instance is an O(1) operation and is atomic.
Writes are synchronous by default; data will be written to disk before an operation returns.
queue-file crate is a feature complete and binary compatible port of `QueueFile` class from
Tape2 by Square, Inc. Check [here](https://github.com/square/tape) the original project.
[Documentation](https://docs.rs/queue-file)
## Usage
To use `queue-file`, first add this to your `Cargo.toml`:
```toml
[dependencies]
queue-file = "1.0"
```
Then, add this to your crate root:
```rust
extern crate queue_file;
```
## Example
```rust
extern crate queue_file;
use queue_file::QueueFile;
fn main() {
let mut qf = QueueFile::open("example.qf").expect("cannot open queue file");
qf.add("ELEMENT #1".as_bytes()).expect("add failed");
qf.add("ELEMENT #2".as_bytes()).expect("add failed");
qf.add("ELEMENT #3".as_bytes()).expect("add failed");
qf.remove().expect("remove failed");
for (index, elem) in qf.iter().enumerate() {
println!(
"{}: {} bytes -> {}",
index,
elem.len(),
std::str::from_utf8(&elem).unwrap_or("<invalid>")
);
}
qf.clear().expect("clear failed");
}
```
## License
This project is licensed under the [Apache 2.0 license](LICENSE).