grin/util/src/lib.rs
Ignotus Peverell 15ea8da34a
New Chain struct acting as facade for all chain operations
Introduce a new Chain struct that maintains the current head,
acts as facade to the store and the block processing pipeline
and handles all appropriate locking.

All higher level components, like the overall server, REST APIs
and miner have been update to only depend on Chain. Cleaned up
some duplication and tests now that there's a single entry point
to all blockchain operations.
2017-07-04 09:17:11 -07:00

53 lines
1.7 KiB
Rust

// Copyright 2016 The Grin Developers
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
/// Various low-level utilities that factor Rust patterns that are frequent
/// within the grin codebase.
use std::cell::{RefCell, Ref};
#[allow(unused_imports)]
use std::ops::Deref;
mod hex;
pub use hex::*;
// Encapsulation of a RefCell<Option<T>> for one-time initialization after
// construction. This implementation will purposefully fail hard if not used
// properly, for example if it's not initialized before being first used
// (borrowed).
#[derive(Clone)]
pub struct OneTime<T> {
inner: RefCell<Option<T>>,
}
unsafe impl<T> Sync for OneTime<T> {}
unsafe impl<T> Send for OneTime<T> {}
impl<T> OneTime<T> {
/// Builds a new uninitialized OneTime.
pub fn new() -> OneTime<T> {
OneTime { inner: RefCell::new(None) }
}
/// Initializes the OneTime, should only be called once after construction.
pub fn init(&self, value: T) {
let mut inner_mut = self.inner.borrow_mut();
*inner_mut = Some(value);
}
/// Borrows the OneTime, should only be called after initialization.
pub fn borrow(&self) -> Ref<T> {
Ref::map(self.inner.borrow(), |o| o.as_ref().unwrap())
}
}