mvcc_cell is a multiversion concurrency control-based
transactional-memory system for Rust.
Transactions are fully isolated and serialized with respect to controlled values: * Each transaction sees a fixed snapshot as of its start time * Any concurrent commits to cells that a transaction has accessed will prevent that transaction from committing
``` use mvcc_cell::{Mvcc,MvccCell}; let mvcc = Mvcc::new();
// Create a transactional slot let slot = MvccCell::new(&mvcc, Box::new(0));
// Start concurrent transactions let mut t1 = mvcc.begin(); let mut t2 = mvcc.begin(); let ro = mvcc.begin();
// Uncommitted values are not visible outside the transaction t1[&slot] = 42; assert_eq!(t2[&slot], 0);
// First committer wins, regardless of actual modification order t2[&slot] = 7; assert!(t2.trycommit().isok());
// Failed commits return the transaction, so you can still read // the computed values let t1fail = t1.trycommit().unwraperr(); asserteq!(t1_fail[&slot], 42);
// Transactions always read the values that were current when // begin() was called. asserteq!(ro[&slot], 0); asserteq!(mvcc.begin()[&slot], 7); ```