wschwab / transience

A Solidity library for transient storage management ✨

✨ Transience

A Solidity library for transient storage

Transience is a Solidity library for safely managing transient storage in smart contracts. It stores values by call depth, allowing reentrancy-aware functions that ensure isolated storage across reentrant calls.

Features

• Transient Storage: Transience offers methods for writing and reading transient storage without having to use assembly/Yul.

• Reentrancy Awareness: Transience keeps track of the current call depth, preventing a reentrant function call from overwriting its parent's transient storage location.

How It Works

Transience uses a unique slot identifier and the current call depth to determine a distinct storage location. The library provides two main functions:

• get(bytes32 _slot): Retrieves the value in transient storage corresponding to _slot at the current call depth.
• set(bytes32 _slot, uint256 _value): Sets _value as the value in transient storage corresponding to _slot at the current call depth.

The TransientReentrancyAware contract offers a reentrantAware modifier that automatically increments and decrements the call depth when entering and exiting a function, ensuring isolation from calls at other call depths (i.e., from a reentrant call).

Getting Started

1. Install the library in your Solidity project

forge install ethereum-optimism/transience

2. Import the library's contracts in your smart contract

import {TransientContext, TransientReentrancyAware} from "transience/src/TransientContext.sol";

3. Inherit from TransientReentrancyAware to access the reentrantAware modifier
4. Use get(bytes32 _slot) and set(bytes32 _slot, uint256 _value) to retrieve and set values in transient storage

Contribute & Feedback

Feel free to raise an issue, suggest a feature, or even fork the repository for personal tweaks. If you'd like to contribute, please fork the repository and make changes as you'd like. Pull requests are warmly welcome.