src/config/user.rs: implement user config cache

This commit is contained in:
Dietmar Maurer 2020-04-14 13:45:45 +02:00
parent 9765092ede
commit 68ccdf09a4

View File

@ -1,6 +1,8 @@
use std::collections::HashMap;
use std::sync::{Arc, RwLock};
use failure::*;
use lazy_static::lazy_static;
use std::collections::HashMap;
use serde::{Serialize, Deserialize};
use serde_json::json;
@ -139,6 +141,41 @@ pub fn config() -> Result<(SectionConfigData, [u8;32]), Error> {
Ok((data, digest))
}
pub fn cached_config() -> Result<(Arc<SectionConfigData>,[u8;32]), Error> {
struct ConfigCache {
data: Option<(Arc<SectionConfigData>,[u8;32])>,
last_mtime: i64,
last_mtime_nsec: i64,
}
lazy_static! {
static ref CACHED_CONFIG: RwLock<ConfigCache> = RwLock::new(
ConfigCache { data: None, last_mtime: 0, last_mtime_nsec: 0 });
}
let stat = nix::sys::stat::stat(USER_CFG_FILENAME)?;
{ // limit scope
let cache = CACHED_CONFIG.read().unwrap();
if stat.st_mtime == cache.last_mtime && stat.st_mtime_nsec == cache.last_mtime_nsec {
if let Some((ref config, ref digest)) = cache.data {
return Ok((config.clone(), *digest));
}
}
}
let (config, digest) = config()?;
let config = Arc::new(config);
let mut cache = CACHED_CONFIG.write().unwrap();
cache.last_mtime = stat.st_mtime;
cache.last_mtime_nsec = stat.st_mtime_nsec;
cache.data = Some((config.clone(), digest.clone()));
Ok((config, digest))
}
pub fn save_config(config: &SectionConfigData) -> Result<(), Error> {
let raw = CONFIG.write(USER_CFG_FILENAME, &config)?;