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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
//! This module implements the primitive functions to implement
//! safe updating from the server.
use crate::error::Result;
use crate::stateful::persistence::{Database, StoreId, Writer};
use crate::Experiment;
const KEY_PENDING_UPDATES: &str = "pending-experiment-updates";
pub fn write_pending_experiments(
db: &Database,
writer: &mut Writer,
experiments: Vec<Experiment>,
) -> Result<()> {
db.get_store(StoreId::Updates)
.put(writer, KEY_PENDING_UPDATES, &experiments)
}
pub fn read_and_remove_pending_experiments(
db: &Database,
writer: &mut Writer,
) -> Result<Option<Vec<Experiment>>> {
let store = db.get_store(StoreId::Updates);
let experiments = store.get::<Vec<Experiment>, _>(writer, KEY_PENDING_UPDATES)?;
// Only clear the store if there's updates available.
// If we're accidentally called from the main thread,
// we don't want to be writing unless we absolutely have to.
if experiments.is_some() {
store.clear(writer)?;
}
// An empty Some(vec![]) is "updates of an empty list" i.e. unenrolling from all experiments
// None is "there are no pending updates".
Ok(experiments)
}