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///Immutable, non-custodial, conditional smart contract escrow.
   ╚═══════╝  ╚═╝ ╚═══════╝   ╚════════╝ ╚═══╝ ╚══════╝ ╚════╝

Overview

Immutable, non-custodial, flexibly-conditioned escrow, transfers, and swaps.

All LeXscroW types have the following features:

• Ownerless unique contract deployment
• Optional conditions for execution, including signatures, time, oracle-fed data, and more, which are immutable from construction and may be combined
• specify depositing part(ies) or allow any address to deposit (open offer)
• parties may replace their own address, and may be an EOA or a contract
• mutual early termination option
• expiration denominated in seconds / Unix time
• re-usable until expiration

As all parameters aside from parties' addresses are immutable upon a LeXscroW's deployment, configuration of each such parameter is critical.

Below is some basic information on each type of LeXscroW. For more details, please consult the documentation.

Directory

README
LICENSE
└─ docs
   ├─_overview.mdx
   ├─_design.mdx
   ├─_deploy.mdx
   └─_use.mdx
└─ src
   ├─ DoubleTokenLexscrow.sol
   ├─ DoubleTokenLexscrowFactory.sol
   ├─ EthLexscrow.sol
   ├─ EthLexscrowFactory.sol
   ├─ TokenLexscrow.sol
   ├─ TokenLexscrowFactory.sol
   └─ libs
      └─ LexscrowConditionManager.sol
   └─ test
      ├─ DoubleTokenLexscrow.t.sol
      ├─ DoubleTokenLexscrowFactory.t.sol
      ├─ EthLexscrow.t.sol
      ├─ EthLexscrowFactory.t.sol
      ├─ LexscrowConditionManager.t.sol
      ├─ TokenLexscrow.t.sol
      └─ TokenLexscrowFactory.t.sol

DoubleTokenLexscrow

Conditional Atomic Token Swaps

Bilateral smart escrow contract for (non-fee-on-transfer, non-rebasing) ERC20 tokens.

• buyer (or, if an open offer, any address) deposits token1 and seller (or if an open offer, any address) deposits token2 via depositTokens() or depositTokensWithPermit()

• if desired, buyer may replace its address by passing the new address to updateBuyer(), and seller may do the same with updateSeller()

• parties may choose to mutually terminate early by passing true to electToTerminate(); if both do so, their deposited tokens will be returned and the LeXscroW will be expired

• execute() is not permissioned, and thus may be called by any address. If called, the LeXscrow executes and simultaneously releases totalAmount1 of token1 to seller and totalAmount2 of token2 to buyer iff:

  (1) buyer and seller have respectively deposited totalAmount1 + any applicable fee1 of token1 and totalAmount2 + any applicable fee2 of token2,

  (2) expirationTime > block.timestamp, and

  (3) if there is/are condition(s), such condition(s) is/are satisfied upon the external call in execute().

If executed, the LeXscroW is re-usable by parties until the set expiration time.

Otherwise, all deposited amounts of token1 are returned to buyer and all deposited amounts of token2 are returned to seller if the LeXscroW expires.

TokenLexscrow

Conditional Token Payments

Unilateral smart escrow contract for (non-fee-on-transfer, non-rebasing) ERC20 tokens.

• initialized with a deposit amount which can be any amount up to the totalAmount, and may be refundable or non-refundable to buyer upon expiry

• buyer (or, if an open offer, any address) deposits via depositTokens() or depositTokensWithPermit()

• if desired, buyer may replace its address by passing the new address to updateBuyer(), and seller may do the same with updateSeller()

• seller may call rejectDepositor() to reject a depositing address, which will cause any amount deposited by such address to become withdrawable (via withdraw()) by the rejected depositor. Also enables early mutual termination.

• execute() is not permissioned, and thus may be called by any address. If called, the LeXscroW executes and simultaneously releases totalAmount to seller iff:

  (1) buyer has deposited totalAmount + any applicable fee net of any pendingWithdraw amount,

  (2) expirationTime > block.timestamp,

  (3) if there is/are condition(s), such condition(s) is/are satisfied upon the external call in execute().

If executed, the LeXscroW is re-usable by parties until the set expiration time.

Otherwise, amount held in the LeXscroW will be treated according to the code in checkIfExpired() when called following expiry. If expired, the applicable party must call withdraw() to receive their tokens.

EthLexscrow

Conditional Gas Token Transfers

Unilateral smart escrow contract for native gas tokens, denominated in 1e18 decimals (wei).

• initialized with a deposit amount which can be any amount up to the totalAmount, and may be refundable or non-refundable to buyer upon expiry

• buyer (or, if an open offer, any address) deposits by sending amount directly to the LeXscroW contract address and thus invoking the receive() function. The conditional logic rejects any amount in excess of totalWithFee

• if desired, buyer may replace its address by passing the new address to updateBuyer(), and seller may do the same with updateSeller()

• seller may call rejectDepositor() to reject a depositing address, which will cause any amount deposited by such address to become withdrawable (via withdraw()) by the rejected depositor. Also enables early mutual termination.

• execute() is not permissioned, and thus may be called by any address. If called, the LeXscroW executes and simultaneously releases totalAmount to seller iff:

  (1) buyer has deposited totalAmount + any applicable fee net of any pendingWithdraw amount,

  (2) expirationTime > block.timestamp, and

  (3) if there is/are condition(s), such condition(s) is/are satisfied upon the external call in execute().

If executed, the LeXscroW is re-usable by parties until the set expiration time.

Otherwise, amount held in the LeXscroW will be treated according to the code in checkIfExpired() when called following expiry. If expired, the applicable party must call withdraw() to receive their funds.

Other Contracts

• DoubleTokenLexscrowFactory, TokenLexscrowFactory, and EthLexscrowFactory set any applicable fee amounts, fee receiver address, and enable easy deployment of the corresponding LeXscroW type (including simultaneous deployment of a Ricardian Tripler and a corresponding LeXscroW where supported).

• LexscrowConditionManager is an adaptation of the BORG-CORE ConditionManager, without auth/access control (and thus also the ability to add or remove conditions post-deployment) in favor of immutability.

Prerequisites

Before you begin, ensure you have the following installed:

• Node.js
• Foundry
• solc v0.8.20

Installation

To set up the project locally, follow these steps:

1. Clone the repository

   git clone https://github.com/MetaLex-Tech/LeXscroW
   cd LeXscroW

2. Install dependencies

   foundryup # Update Foundry tools
   forge install # Install project dependencies

3. Compile Contracts

   forge build