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use crate::{CryptoKVStorage, Error, GetResponse, KVStorage};
use diem_temppath::TempPath;
use diem_time_service::{TimeService, TimeServiceTrait};
use serde::{de::DeserializeOwned, Serialize};
use serde_json::Value;
use std::{
collections::HashMap,
fs::{self, File},
io::{Read, Write},
path::PathBuf,
};
pub struct OnDiskStorage {
file_path: PathBuf,
temp_path: TempPath,
time_service: TimeService,
}
impl OnDiskStorage {
pub fn new(file_path: PathBuf) -> Self {
Self::new_with_time_service(file_path, TimeService::real())
}
fn new_with_time_service(file_path: PathBuf, time_service: TimeService) -> Self {
if !file_path.exists() {
File::create(&file_path).expect("Unable to create storage");
}
let file_dir = file_path
.parent()
.map_or(PathBuf::new(), |p| p.to_path_buf());
Self {
file_path,
temp_path: TempPath::new_with_temp_dir(file_dir),
time_service,
}
}
fn read(&self) -> Result<HashMap<String, Value>, Error> {
let mut file = File::open(&self.file_path)?;
let mut contents = String::new();
file.read_to_string(&mut contents)?;
if contents.is_empty() {
return Ok(HashMap::new());
}
let data = serde_json::from_str(&contents)?;
Ok(data)
}
fn write(&self, data: &HashMap<String, Value>) -> Result<(), Error> {
let contents = serde_json::to_vec(data)?;
let mut file = File::create(self.temp_path.path())?;
file.write_all(&contents)?;
fs::rename(&self.temp_path, &self.file_path)?;
Ok(())
}
}
impl KVStorage for OnDiskStorage {
fn available(&self) -> Result<(), Error> {
Ok(())
}
fn get<V: DeserializeOwned>(&self, key: &str) -> Result<GetResponse<V>, Error> {
let mut data = self.read()?;
data.remove(key)
.ok_or_else(|| Error::KeyNotSet(key.to_string()))
.and_then(|value| serde_json::from_value(value).map_err(|e| e.into()))
}
fn set<V: Serialize>(&mut self, key: &str, value: V) -> Result<(), Error> {
let now = self.time_service.now_secs();
let mut data = self.read()?;
data.insert(
key.to_string(),
serde_json::to_value(&GetResponse::new(value, now))?,
);
self.write(&data)
}
#[cfg(any(test, feature = "testing"))]
fn reset_and_clear(&mut self) -> Result<(), Error> {
self.write(&HashMap::new())
}
}
impl CryptoKVStorage for OnDiskStorage {}