OVM_FraudVerifier.sol

contract OVM_FraudVerifier is Lib_AddressResolver, OVM_FraudContributor, iOVM_FraudVerifier {
    /**
     * Finalizes the fraud verification process.
     * @param _preStateRoot State root before the fraudulent transaction.
     * @param _preStateRootBatchHeader Batch header for the provided pre-state root.
     * @param _preStateRootProof Inclusion proof for the provided pre-state root.
     * @param _txHash The transaction for the state root
     * @param _postStateRoot State root after the fraudulent transaction.
     * @param _postStateRootBatchHeader Batch header for the provided post-state root.
     * @param _postStateRootProof Inclusion proof for the provided post-state root.
     */
    function finalizeFraudVerification(
        bytes32 _preStateRoot,
        Lib_OVMCodec.ChainBatchHeader memory _preStateRootBatchHeader,
        Lib_OVMCodec.ChainInclusionProof memory _preStateRootProof,
        bytes32 _txHash,
        bytes32 _postStateRoot,
        Lib_OVMCodec.ChainBatchHeader memory _postStateRootBatchHeader,
        Lib_OVMCodec.ChainInclusionProof memory _postStateRootProof
    )
        override
        public
        contributesToFraudProof(_preStateRoot, _txHash)
    {
        iOVM_StateTransitioner transitioner = getStateTransitioner(_preStateRoot, _txHash);
        
        // ... a bunch of require statements omitted

        // If the post state root did not match, then there was fraud and we should delete the batch
        require(
            _postStateRoot != transitioner.getPostStateRoot(),
            "State transition has not been proven fraudulent."
        );
        
        _cancelStateTransition(_postStateRootBatchHeader, _preStateRoot);

        // TEMPORARY: Remove the transitioner; for minnet.
        transitioners[keccak256(abi.encodePacked(_preStateRoot, _txHash))] = iOVM_StateTransitioner(0x0000000000000000000000000000000000000000);

        emit FraudProofFinalized(
            _preStateRoot,
            _preStateRootProof.index,
            _txHash,
            msg.sender
        );
    }
    
    /**
     * Removes a state transition from the state commitment chain.
     * @param _postStateRootBatchHeader Header for the post-state root.
     * @param _preStateRoot Pre-state root hash.
     */
    function _cancelStateTransition(
        Lib_OVMCodec.ChainBatchHeader memory _postStateRootBatchHeader,
        bytes32 _preStateRoot
    )
        internal
    {
        iOVM_StateCommitmentChain ovmStateCommitmentChain = iOVM_StateCommitmentChain(resolve("OVM_StateCommitmentChain"));
        iOVM_BondManager ovmBondManager = iOVM_BondManager(resolve("OVM_BondManager"));

        // Delete the state batch.
        ovmStateCommitmentChain.deleteStateBatch(
            _postStateRootBatchHeader
        );

        // Get the timestamp and publisher for that block.
        (uint256 timestamp, address publisher) = abi.decode(_postStateRootBatchHeader.extraData, (uint256, address));

        // Slash the bonds at the bond manager.
        ovmBondManager.finalize(
            _preStateRoot,
            publisher,
            timestamp
        );
    }
}