LocalProver

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Overview

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Constructor

constructor(address portal)

• ChainIdTooLarge(uint256): Current chain ID exceeds uint64.max

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State Variables

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_PORTAL

IPortal private immutable _PORTAL

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_CHAIN_ID

uint64 private immutable _CHAIN_ID

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_flashFulfillInProgress

bytes32 private _flashFulfillInProgress

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Core Functions

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prove

function prove(
    address /* sender */,
    uint64 /* sourceChainId */,
    bytes calldata /* encodedProofs */,
    bytes calldata /* data */
) external payable

• Intentionally empty (no-op)
• Does not revert to allow usage with fulfillAndProve

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provenIntents

function provenIntents(
    bytes32 intentHash
) public view returns (ProofData memory)

• claimant (address): Address eligible for rewards
• destination (uint64): Chain ID (_CHAIN_ID)

1. Griefing Protection: If Portal.claimants contains LocalProver address (without using flashFulfill)
   • Returns ProofData(address(0), 0) to treat intent as unfulfilled
   • Allows refunds after deadline
2. Intent Fulfilled: If Portal.claimants contains valid solver address
   • Validates address is valid EVM address
   • Returns ProofData(solver, _CHAIN_ID)
   • If invalid EVM address, returns ProofData(address(0), 0) for griefing protection
3. Flash Fulfill In Progress: If _flashFulfillInProgress == intentHash
   • Returns ProofData(address(this), _CHAIN_ID)
   • Enables withdrawal to LocalProver during atomic execution
4. Intent Not Fulfilled:
   • Returns ProofData(address(0), 0)

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flashFulfill

function flashFulfill(
    Route calldata route,
    Reward calldata reward,
    bytes32 claimant
) external payable nonReentrant returns (bytes[] memory results)

1. CHECKS:
   • Validates claimant is not zero
   • Validates claimant is not LocalProver address
   • Computes intentHash from route and reward
2. EFFECTS:
   • Sets _flashFulfillInProgress = intentHash
3. INTERACTIONS:
   • Withdraws reward from vault to LocalProver
   • Approves Portal to spend route tokens
   • Calls Portal.fulfill with entire contract balance
   • Portal records actual claimant (not LocalProver)
4. EFFECTS (Cleanup):
   • Transfers all remaining reward tokens to claimant
   • Transfers all remaining native ETH to claimant
   • Emits FlashFulfilled event

• All ERC20 tokens in reward.tokens (minus any consumed by route.tokens)
• All native ETH from reward.nativeAmount (minus consumed by route.nativeAmount)
• Plus any msg.value sent by caller

• InvalidClaimant(): Claimant is zero or LocalProver address
• NativeTransferFailed(): Native token transfer to claimant failed

• Uses nonReentrant modifier to prevent reentrancy attacks
• Follows checks-effects-interactions pattern

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challengeIntentProof

function challengeIntentProof(
    uint64 /* destination */,
    bytes32 /* routeHash */,
    bytes32 /* rewardHash */
) external pure

• Intentionally empty (no-op)

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getProofType

function getProofType() external pure returns (string memory)

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receive

receive() external payable

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Events

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FlashFulfilled

event FlashFulfilled(
    bytes32 indexed intentHash,
    bytes32 claimant,
    uint256 remainingNative
)

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Errors

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InvalidClaimant

error InvalidClaimant()

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NativeTransferFailed

error NativeTransferFailed()

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ChainIdTooLarge

error ChainIdTooLarge(uint256 chainId)

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Usage Example

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Flash Fulfill an Intent

// Prepare route and reward data
Route memory route = Route({
    steps: [...],
    tokens: [...]
});

Reward memory reward = Reward({
    creator: intentCreator,
    prover: address(localProver),
    deadline: block.timestamp + 1 hours,
    nativeAmount: 0.1 ether,
    tokens: [TokenAmount(rewardToken, 1000e18)]
});

// Flash fulfill (solver specifies themselves as claimant)
bytes32 claimant = bytes32(uint256(uint160(msg.sender)));
bytes[] memory results = localProver.flashFulfill{value: routeNativeAmount}(
    route,
    reward,
    claimant
);

// Solver receives:
// - All reward tokens (minus consumed by route)
// - All reward native (minus consumed by route)
// - Immediately, in single transaction

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Check Proof Status

// Query proof data
IProver.ProofData memory proof = localProver.provenIntents(intentHash);

if (proof.claimant != address(0)) {
    // Intent is proven and fulfilled
    // proof.claimant is the solver
    // proof.destination is the current chain
} else {
    // Intent not yet fulfilled
}

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Griefing Protection

1. LocalProver as Claimant: If someone calls Portal.fulfill with LocalProver as claimant (without using flashFulfill), provenIntents returns address(0) to treat the intent as unfulfilled.
2. Invalid EVM Address: If Portal.claimants contains a non-EVM bytes32 value, provenIntents returns address(0) to allow refunds.

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Flash Fulfill Atomicity

1. Withdraw rewards from vault → LocalProver
2. Approve Portal to spend route tokens
3. Call Portal.fulfill (which executes route steps)
4. Transfer remaining rewards → claimant

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Reentrancy Protection

• Multiple simultaneous flash fulfills
• Cross-intent reentrancy attacks
• State manipulation during execution