Struct File 

pub struct File<T: Serialize + DeserializeOwned + Default> { /* private fields */ }

A state file.

This provides strongly typed access to a JSON file wrapped in a RwLock that writes to disk once write access is dropped.

use statefile::File;
use serde::{Deserialize, Serialize};

// you must specify at least these derivations
#[derive(Serialize, Deserialize, Default)]
struct State {
    foo: String,
    bar: u32,
}

#[tokio::main]
async fn main() {
    // create or open state file at given path
    let mut state = File::<State>::new("mystate.json").await.unwrap();
    // if the file doesn't exist or is empty, State will contain default values

    let mut write_guard = state.write().await; // grab write access
    write_guard.foo = "".to_string();
    write_guard.bar = 10;
    drop(write_guard); // write state by explicitly dropping
}

Implementations

impl<T: Serialize + DeserializeOwned + Default> File<T>

pub async fn new(path: impl AsRef<Path> + Copy) -> Result<Self, Box<dyn Error>>

Create a new state file at the given path

pub async fn read(&self) -> RwLockReadGuard<'_, T>

Locks this state file with shared read access, causing the current task to yield until the lock has been acquired.

pub async fn write(&self) -> WriteGuard<'_, T>

Locks this state file with exclusive write access, causing the current task to yield until the lock has been acquired.