Update Arbitrum's vendored contracts to Nitro (#3692)

Co-authored-by: Francisco <frangio.1@gmail.com>
(cherry picked from commit 9938a85558e43bcadefe411d8e85e4a471de6a32)

CHANGELOG.md

@@ -34,6 +34,7 @@
  * `Ownable2Step`: extension of `Ownable` that makes the ownership transfers a two step process. ([#3620](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3620))
  * `Math` and `SignedMath`: optimize function `max` by using `>` instead of `>=`. ([#3679](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3679))
  * `Math`: Add `log2`, `log10` and `log256`. ([#3670](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3670))
+ * Arbitrum: Update the vendored arbitrum contracts to match the nitro upgrade. ([#3692](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3692))
 
 ### Breaking changes
 

contracts/crosschain/arbitrum/LibArbitrumL1.sol

@@ -4,7 +4,6 @@
 pragma solidity ^0.8.4;
 
 import {IBridge as ArbitrumL1_Bridge} from "../../vendor/arbitrum/IBridge.sol";
-import {IInbox as ArbitrumL1_Inbox} from "../../vendor/arbitrum/IInbox.sol";
 import {IOutbox as ArbitrumL1_Outbox} from "../../vendor/arbitrum/IOutbox.sol";
 import "../errors.sol";
 

contracts/vendor/arbitrum/IArbSys.sol

@@ -1,19 +1,15 @@
-// SPDX-License-Identifier: MIT
-// OpenZeppelin Contracts (last updated v4.6.0) (vendor/arbitrum/IArbSys.sol)
+// Copyright 2021-2022, Offchain Labs, Inc.
+// For license information, see https://github.com/OffchainLabs/nitro/blob/master/LICENSE
+// SPDX-License-Identifier: BUSL-1.1
+
 pragma solidity >=0.4.21 <0.9.0;
 
 /**
- * @title Precompiled contract that exists in every Arbitrum chain at address(100), 0x0000000000000000000000000000000000000064. Exposes a variety of system-level functionality.
+ * @title System level functionality
+ * @notice For use by contracts to interact with core L2-specific functionality.
+ * Precompiled contract that exists in every Arbitrum chain at address(100), 0x0000000000000000000000000000000000000064.
  */
 interface IArbSys {
-    /**
-     * @notice Get internal version number identifying an ArbOS build
-     * @return version number as int
-     */
-    function arbOSVersion() external pure returns (uint256);
-
-    function arbChainID() external view returns (uint256);
-
     /**
      * @notice Get Arbitrum block number (distinct from L1 block number; Arbitrum genesis block has block number 0)
      * @return block number as int
@@ -21,43 +17,44 @@ interface IArbSys {
     function arbBlockNumber() external view returns (uint256);
 
     /**
-     * @notice Send given amount of Eth to dest from sender.
-     * This is a convenience function, which is equivalent to calling sendTxToL1 with empty calldataForL1.
-     * @param destination recipient address on L1
-     * @return unique identifier for this L2-to-L1 transaction.
+     * @notice Get Arbitrum block hash (reverts unless currentBlockNum-256 <= arbBlockNum < currentBlockNum)
+     * @return block hash
      */
-    function withdrawEth(address destination) external payable returns (uint256);
+    function arbBlockHash(uint256 arbBlockNum) external view returns (bytes32);
 
     /**
-     * @notice Send a transaction to L1
-     * @param destination recipient address on L1
-     * @param calldataForL1 (optional) calldata for L1 contract call
-     * @return a unique identifier for this L2-to-L1 transaction.
+     * @notice Gets the rollup's unique chain identifier
+     * @return Chain identifier as int
      */
-    function sendTxToL1(address destination, bytes calldata calldataForL1) external payable returns (uint256);
+    function arbChainID() external view returns (uint256);
 
     /**
-     * @notice get the number of transactions issued by the given external account or the account sequence number of the given contract
-     * @param account target account
-     * @return the number of transactions issued by the given external account or the account sequence number of the given contract
+     * @notice Get internal version number identifying an ArbOS build
+     * @return version number as int
      */
-    function getTransactionCount(address account) external view returns (uint256);
+    function arbOSVersion() external view returns (uint256);
 
     /**
-     * @notice get the value of target L2 storage slot
-     * This function is only callable from address 0 to prevent contracts from being able to call it
-     * @param account target account
-     * @param index target index of storage slot
-     * @return stotage value for the given account at the given index
+     * @notice Returns 0 since Nitro has no concept of storage gas
+     * @return uint 0
      */
-    function getStorageAt(address account, uint256 index) external view returns (uint256);
+    function getStorageGasAvailable() external view returns (uint256);
 
     /**
-     * @notice check if current call is coming from l1
-     * @return true if the caller of this was called directly from L1
+     * @notice (deprecated) check if current call is top level (meaning it was triggered by an EoA or a L1 contract)
+     * @dev this call has been deprecated and may be removed in a future release
+     * @return true if current execution frame is not a call by another L2 contract
      */
     function isTopLevelCall() external view returns (bool);
 
+    /**
+     * @notice map L1 sender contract address to its L2 alias
+     * @param sender sender address
+     * @param unused argument no longer used
+     * @return aliased sender address
+     */
+    function mapL1SenderContractAddressToL2Alias(address sender, address unused) external pure returns (address);
+
     /**
      * @notice check if the caller (of this caller of this) is an aliased L1 contract address
      * @return true iff the caller's address is an alias for an L1 contract address
@@ -71,19 +68,55 @@ interface IArbSys {
     function myCallersAddressWithoutAliasing() external view returns (address);
 
     /**
-     * @notice map L1 sender contract address to its L2 alias
-     * @param sender sender address
-     * @param dest destination address
-     * @return aliased sender address
+     * @notice Send given amount of Eth to dest from sender.
+     * This is a convenience function, which is equivalent to calling sendTxToL1 with empty data.
+     * @param destination recipient address on L1
+     * @return unique identifier for this L2-to-L1 transaction.
      */
-    function mapL1SenderContractAddressToL2Alias(address sender, address dest) external pure returns (address);
+    function withdrawEth(address destination) external payable returns (uint256);
 
     /**
-     * @notice get the caller's amount of available storage gas
-     * @return amount of storage gas available to the caller
+     * @notice Send a transaction to L1
+     * @dev it is not possible to execute on the L1 any L2-to-L1 transaction which contains data
+     * to a contract address without any code (as enforced by the Bridge contract).
+     * @param destination recipient address on L1
+     * @param data (optional) calldata for L1 contract call
+     * @return a unique identifier for this L2-to-L1 transaction.
      */
-    function getStorageGasAvailable() external view returns (uint256);
+    function sendTxToL1(address destination, bytes calldata data) external payable returns (uint256);
+
+    /**
+     * @notice Get send Merkle tree state
+     * @return size number of sends in the history
+     * @return root root hash of the send history
+     * @return partials hashes of partial subtrees in the send history tree
+     */
+    function sendMerkleTreeState()
+        external
+        view
+        returns (
+            uint256 size,
+            bytes32 root,
+            bytes32[] memory partials
+        );
+
+    /**
+     * @notice creates a send txn from L2 to L1
+     * @param position = (level << 192) + leaf = (0 << 192) + leaf = leaf
+     */
+    event L2ToL1Tx(
+        address caller,
+        address indexed destination,
+        uint256 indexed hash,
+        uint256 indexed position,
+        uint256 arbBlockNum,
+        uint256 ethBlockNum,
+        uint256 timestamp,
+        uint256 callvalue,
+        bytes data
+    );
 
+    /// @dev DEPRECATED in favour of the new L2ToL1Tx event above after the nitro upgrade
     event L2ToL1Transaction(
         address caller,
         address indexed destination,
@@ -96,4 +129,12 @@ interface IArbSys {
         uint256 callvalue,
         bytes data
     );
+
+    /**
+     * @notice logs a merkle branch for proof synthesis
+     * @param reserved an index meant only to align the 4th index with L2ToL1Transaction's 4th event
+     * @param hash the merkle hash
+     * @param position = (level << 192) + leaf
+     */
+    event SendMerkleUpdate(uint256 indexed reserved, bytes32 indexed hash, uint256 indexed position);
 }

contracts/vendor/arbitrum/IBridge.sol

@@ -1,23 +1,9 @@
-// SPDX-License-Identifier: Apache-2.0
-// OpenZeppelin Contracts (last updated v4.6.0) (vendor/arbitrum/IBridge.sol)
-
-/*
- * Copyright 2021, Offchain Labs, Inc.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-pragma solidity ^0.8.0;
+// Copyright 2021-2022, Offchain Labs, Inc.
+// For license information, see https://github.com/nitro/blob/master/LICENSE
+// SPDX-License-Identifier: BUSL-1.1
+
+// solhint-disable-next-line compiler-version
+pragma solidity >=0.6.9 <0.9.0;
 
 interface IBridge {
     event MessageDelivered(
@@ -26,41 +12,97 @@ interface IBridge {
         address inbox,
         uint8 kind,
         address sender,
-        bytes32 messageDataHash
+        bytes32 messageDataHash,
+        uint256 baseFeeL1,
+        uint64 timestamp
     );
 
-    event BridgeCallTriggered(address indexed outbox, address indexed destAddr, uint256 amount, bytes data);
+    event BridgeCallTriggered(address indexed outbox, address indexed to, uint256 value, bytes data);
 
     event InboxToggle(address indexed inbox, bool enabled);
 
     event OutboxToggle(address indexed outbox, bool enabled);
 
-    function deliverMessageToInbox(
+    event SequencerInboxUpdated(address newSequencerInbox);
+
+    function allowedDelayedInboxList(uint256) external returns (address);
+
+    function allowedOutboxList(uint256) external returns (address);
+
+    /// @dev Accumulator for delayed inbox messages; tail represents hash of the current state; each element represents the inclusion of a new message.
+    function delayedInboxAccs(uint256) external view returns (bytes32);
+
+    /// @dev Accumulator for sequencer inbox messages; tail represents hash of the current state; each element represents the inclusion of a new message.
+    function sequencerInboxAccs(uint256) external view returns (bytes32);
+
+    // OpenZeppelin: changed return type from IOwnable
+    function rollup() external view returns (address);
+
+    function sequencerInbox() external view returns (address);
+
+    function activeOutbox() external view returns (address);
+
+    function allowedDelayedInboxes(address inbox) external view returns (bool);
+
+    function allowedOutboxes(address outbox) external view returns (bool);
+
+    function sequencerReportedSubMessageCount() external view returns (uint256);
+
+    /**
+     * @dev Enqueue a message in the delayed inbox accumulator.
+     *      These messages are later sequenced in the SequencerInbox, either
+     *      by the sequencer as part of a normal batch, or by force inclusion.
+     */
+    function enqueueDelayedMessage(
         uint8 kind,
         address sender,
         bytes32 messageDataHash
     ) external payable returns (uint256);
 
     function executeCall(
-        address destAddr,
-        uint256 amount,
+        address to,
+        uint256 value,
         bytes calldata data
     ) external returns (bool success, bytes memory returnData);
 
-    // These are only callable by the admin
-    function setInbox(address inbox, bool enabled) external;
+    function delayedMessageCount() external view returns (uint256);
 
-    function setOutbox(address inbox, bool enabled) external;
+    function sequencerMessageCount() external view returns (uint256);
 
-    // View functions
+    // ---------- onlySequencerInbox functions ----------
 
-    function activeOutbox() external view returns (address);
+    function enqueueSequencerMessage(
+        bytes32 dataHash,
+        uint256 afterDelayedMessagesRead,
+        uint256 prevMessageCount,
+        uint256 newMessageCount
+    )
+        external
+        returns (
+            uint256 seqMessageIndex,
+            bytes32 beforeAcc,
+            bytes32 delayedAcc,
+            bytes32 acc
+        );
 
-    function allowedInboxes(address inbox) external view returns (bool);
+    /**
+     * @dev Allows the sequencer inbox to submit a delayed message of the batchPostingReport type
+     *      This is done through a separate function entrypoint instead of allowing the sequencer inbox
+     *      to call `enqueueDelayedMessage` to avoid the gas overhead of an extra SLOAD in either
+     *      every delayed inbox or every sequencer inbox call.
+     */
+    function submitBatchSpendingReport(address batchPoster, bytes32 dataHash) external returns (uint256 msgNum);
 
-    function allowedOutboxes(address outbox) external view returns (bool);
+    // ---------- onlyRollupOrOwner functions ----------
+
+    function setSequencerInbox(address _sequencerInbox) external;
+
+    function setDelayedInbox(address inbox, bool enabled) external;
+
+    function setOutbox(address inbox, bool enabled) external;
 
-    function inboxAccs(uint256 index) external view returns (bytes32);
+    // ---------- initializer ----------
 
-    function messageCount() external view returns (uint256);
+    // OpenZeppelin: changed rollup_ type from IOwnable
+    function initialize(address rollup_) external;
 }

contracts/vendor/arbitrum/IDelayedMessageProvider.sol

@@ -0,0 +1,15 @@
+// Copyright 2021-2022, Offchain Labs, Inc.
+// For license information, see https://github.com/nitro/blob/master/LICENSE
+// SPDX-License-Identifier: BUSL-1.1
+
+// solhint-disable-next-line compiler-version
+pragma solidity >=0.6.9 <0.9.0;
+
+interface IDelayedMessageProvider {
+    /// @dev event emitted when a inbox message is added to the Bridge's delayed accumulator
+    event InboxMessageDelivered(uint256 indexed messageNum, bytes data);
+
+    /// @dev event emitted when a inbox message is added to the Bridge's delayed accumulator
+    /// same as InboxMessageDelivered but the batch data is available in tx.input
+    event InboxMessageDeliveredFromOrigin(uint256 indexed messageNum);
+}

contracts/vendor/arbitrum/IInbox.sol

@@ -1,92 +1,151 @@
-// SPDX-License-Identifier: Apache-2.0
-// OpenZeppelin Contracts (last updated v4.6.0) (vendor/arbitrum/IInbox.sol)
-
-/*
- * Copyright 2021, Offchain Labs, Inc.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-pragma solidity ^0.8.0;
-
-import "./IMessageProvider.sol";
-
-interface IInbox is IMessageProvider {
+// Copyright 2021-2022, Offchain Labs, Inc.
+// For license information, see https://github.com/nitro/blob/master/LICENSE
+// SPDX-License-Identifier: BUSL-1.1
+
+// solhint-disable-next-line compiler-version
+pragma solidity >=0.6.9 <0.9.0;
+
+import "./IBridge.sol";
+import "./IDelayedMessageProvider.sol";
+
+interface IInbox is IDelayedMessageProvider {
+    function bridge() external view returns (IBridge);
+
+    // OpenZeppelin: changed return type from ISequencerInbox
+    function sequencerInbox() external view returns (address);
+
+    /**
+     * @notice Send a generic L2 message to the chain
+     * @dev This method is an optimization to avoid having to emit the entirety of the messageData in a log. Instead validators are expected to be able to parse the data from the transaction's input
+     * @param messageData Data of the message being sent
+     */
+    function sendL2MessageFromOrigin(bytes calldata messageData) external returns (uint256);
+
+    /**
+     * @notice Send a generic L2 message to the chain
+     * @dev This method can be used to send any type of message that doesn't require L1 validation
+     * @param messageData Data of the message being sent
+     */
     function sendL2Message(bytes calldata messageData) external returns (uint256);
 
-    function sendUnsignedTransaction(
-        uint256 maxGas,
-        uint256 gasPriceBid,
+    function sendL1FundedUnsignedTransaction(
+        uint256 gasLimit,
+        uint256 maxFeePerGas,
         uint256 nonce,
-        address destAddr,
-        uint256 amount,
+        address to,
         bytes calldata data
-    ) external returns (uint256);
+    ) external payable returns (uint256);
 
-    function sendContractTransaction(
-        uint256 maxGas,
-        uint256 gasPriceBid,
-        address destAddr,
-        uint256 amount,
+    function sendL1FundedContractTransaction(
+        uint256 gasLimit,
+        uint256 maxFeePerGas,
+        address to,
         bytes calldata data
-    ) external returns (uint256);
+    ) external payable returns (uint256);
 
-    function sendL1FundedUnsignedTransaction(
-        uint256 maxGas,
-        uint256 gasPriceBid,
+    function sendUnsignedTransaction(
+        uint256 gasLimit,
+        uint256 maxFeePerGas,
         uint256 nonce,
-        address destAddr,
+        address to,
+        uint256 value,
         bytes calldata data
-    ) external payable returns (uint256);
+    ) external returns (uint256);
 
-    function sendL1FundedContractTransaction(
-        uint256 maxGas,
-        uint256 gasPriceBid,
-        address destAddr,
+    function sendContractTransaction(
+        uint256 gasLimit,
+        uint256 maxFeePerGas,
+        address to,
+        uint256 value,
         bytes calldata data
-    ) external payable returns (uint256);
+    ) external returns (uint256);
 
+    /**
+     * @notice Get the L1 fee for submitting a retryable
+     * @dev This fee can be paid by funds already in the L2 aliased address or by the current message value
+     * @dev This formula may change in the future, to future proof your code query this method instead of inlining!!
+     * @param dataLength The length of the retryable's calldata, in bytes
+     * @param baseFee The block basefee when the retryable is included in the chain, if 0 current block.basefee will be used
+     */
+    function calculateRetryableSubmissionFee(uint256 dataLength, uint256 baseFee) external view returns (uint256);
+
+    /**
+     * @notice Deposit eth from L1 to L2 to address of the sender if sender is an EOA, and to its aliased address if the sender is a contract
+     * @dev This does not trigger the fallback function when receiving in the L2 side.
+     *      Look into retryable tickets if you are interested in this functionality.
+     * @dev This function should not be called inside contract constructors
+     */
+    function depositEth() external payable returns (uint256);
+
+    /**
+     * @notice Put a message in the L2 inbox that can be reexecuted for some fixed amount of time if it reverts
+     * @dev all msg.value will deposited to callValueRefundAddress on L2
+     * @dev Gas limit and maxFeePerGas should not be set to 1 as that is used to trigger the RetryableData error
+     * @param to destination L2 contract address
+     * @param l2CallValue call value for retryable L2 message
+     * @param maxSubmissionCost Max gas deducted from user's L2 balance to cover base submission fee
+     * @param excessFeeRefundAddress gasLimit x maxFeePerGas - execution cost gets credited here on L2 balance
+     * @param callValueRefundAddress l2Callvalue gets credited here on L2 if retryable txn times out or gets cancelled
+     * @param gasLimit Max gas deducted from user's L2 balance to cover L2 execution. Should not be set to 1 (magic value used to trigger the RetryableData error)
+     * @param maxFeePerGas price bid for L2 execution. Should not be set to 1 (magic value used to trigger the RetryableData error)
+     * @param data ABI encoded data of L2 message
+     * @return unique message number of the retryable transaction
+     */
     function createRetryableTicket(
-        address destAddr,
-        uint256 arbTxCallValue,
+        address to,
+        uint256 l2CallValue,
         uint256 maxSubmissionCost,
-        address submissionRefundAddress,
-        address valueRefundAddress,
-        uint256 maxGas,
-        uint256 gasPriceBid,
+        address excessFeeRefundAddress,
+        address callValueRefundAddress,
+        uint256 gasLimit,
+        uint256 maxFeePerGas,
         bytes calldata data
     ) external payable returns (uint256);
 
-    function createRetryableTicketNoRefundAliasRewrite(
-        address destAddr,
-        uint256 arbTxCallValue,
+    /**
+     * @notice Put a message in the L2 inbox that can be reexecuted for some fixed amount of time if it reverts
+     * @dev Same as createRetryableTicket, but does not guarantee that submission will succeed by requiring the needed funds
+     * come from the deposit alone, rather than falling back on the user's L2 balance
+     * @dev Advanced usage only (does not rewrite aliases for excessFeeRefundAddress and callValueRefundAddress).
+     * createRetryableTicket method is the recommended standard.
+     * @dev Gas limit and maxFeePerGas should not be set to 1 as that is used to trigger the RetryableData error
+     * @param to destination L2 contract address
+     * @param l2CallValue call value for retryable L2 message
+     * @param maxSubmissionCost Max gas deducted from user's L2 balance to cover base submission fee
+     * @param excessFeeRefundAddress gasLimit x maxFeePerGas - execution cost gets credited here on L2 balance
+     * @param callValueRefundAddress l2Callvalue gets credited here on L2 if retryable txn times out or gets cancelled
+     * @param gasLimit Max gas deducted from user's L2 balance to cover L2 execution. Should not be set to 1 (magic value used to trigger the RetryableData error)
+     * @param maxFeePerGas price bid for L2 execution. Should not be set to 1 (magic value used to trigger the RetryableData error)
+     * @param data ABI encoded data of L2 message
+     * @return unique message number of the retryable transaction
+     */
+    function unsafeCreateRetryableTicket(
+        address to,
+        uint256 l2CallValue,
         uint256 maxSubmissionCost,
-        address submissionRefundAddress,
-        address valueRefundAddress,
-        uint256 maxGas,
-        uint256 gasPriceBid,
+        address excessFeeRefundAddress,
+        address callValueRefundAddress,
+        uint256 gasLimit,
+        uint256 maxFeePerGas,
         bytes calldata data
     ) external payable returns (uint256);
 
-    function depositEth(uint256 maxSubmissionCost) external payable returns (uint256);
+    // ---------- onlyRollupOrOwner functions ----------
 
-    function bridge() external view returns (address);
+    /// @notice pauses all inbox functionality
+    function pause() external;
 
-    function pauseCreateRetryables() external;
+    /// @notice unpauses all inbox functionality
+    function unpause() external;
 
-    function unpauseCreateRetryables() external;
+    // ---------- initializer ----------
 
-    function startRewriteAddress() external;
+    /**
+     * @dev function to be called one time during the inbox upgrade process
+     *      this is used to fix the storage slots
+     */
+    function postUpgradeInit(IBridge _bridge) external;
 
-    function stopRewriteAddress() external;
+    // OpenZeppelin: changed _sequencerInbox type from ISequencerInbox
+    function initialize(IBridge _bridge, address _sequencerInbox) external;
 }

contracts/vendor/arbitrum/IMessageProvider.sol

@@ -1,26 +0,0 @@
-// SPDX-License-Identifier: Apache-2.0
-// OpenZeppelin Contracts (last updated v4.6.0) (vendor/arbitrum/IMessageProvider.sol)
-
-/*
- * Copyright 2021, Offchain Labs, Inc.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-pragma solidity ^0.8.0;
-
-interface IMessageProvider {
-    event InboxMessageDelivered(uint256 indexed messageNum, bytes data);
-
-    event InboxMessageDeliveredFromOrigin(uint256 indexed messageNum);
-}

contracts/vendor/arbitrum/IOutbox.sol

@@ -1,51 +1,120 @@
-// SPDX-License-Identifier: Apache-2.0
-// OpenZeppelin Contracts (last updated v4.6.0) (vendor/arbitrum/IOutbox.sol)
-
-/*
- * Copyright 2021, Offchain Labs, Inc.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-pragma solidity ^0.8.0;
+// Copyright 2021-2022, Offchain Labs, Inc.
+// For license information, see https://github.com/nitro/blob/master/LICENSE
+// SPDX-License-Identifier: BUSL-1.1
+
+// solhint-disable-next-line compiler-version
+pragma solidity >=0.6.9 <0.9.0;
+
+import "./IBridge.sol";
 
 interface IOutbox {
-    event OutboxEntryCreated(
-        uint256 indexed batchNum,
-        uint256 outboxEntryIndex,
-        bytes32 outputRoot,
-        uint256 numInBatch
-    );
+    event SendRootUpdated(bytes32 indexed blockHash, bytes32 indexed outputRoot);
     event OutBoxTransactionExecuted(
-        address indexed destAddr,
+        address indexed to,
         address indexed l2Sender,
-        uint256 indexed outboxEntryIndex,
+        uint256 indexed zero,
         uint256 transactionIndex
     );
 
+    function rollup() external view returns (address); // the rollup contract
+
+    function bridge() external view returns (IBridge); // the bridge contract
+
+    function spent(uint256) external view returns (bytes32); // packed spent bitmap
+
+    function roots(bytes32) external view returns (bytes32); // maps root hashes => L2 block hash
+
+    // solhint-disable-next-line func-name-mixedcase
+    function OUTBOX_VERSION() external view returns (uint128); // the outbox version
+
+    function updateSendRoot(bytes32 sendRoot, bytes32 l2BlockHash) external;
+
+    /// @notice When l2ToL1Sender returns a nonzero address, the message was originated by an L2 account
+    ///         When the return value is zero, that means this is a system message
+    /// @dev the l2ToL1Sender behaves as the tx.origin, the msg.sender should be validated to protect against reentrancies
     function l2ToL1Sender() external view returns (address);
 
+    /// @return l2Block return L2 block when the L2 tx was initiated or 0 if no L2 to L1 transaction is active
     function l2ToL1Block() external view returns (uint256);
 
+    /// @return l1Block return L1 block when the L2 tx was initiated or 0 if no L2 to L1 transaction is active
     function l2ToL1EthBlock() external view returns (uint256);
 
+    /// @return timestamp return L2 timestamp when the L2 tx was initiated or 0 if no L2 to L1 transaction is active
     function l2ToL1Timestamp() external view returns (uint256);
 
-    function l2ToL1BatchNum() external view returns (uint256);
-
+    /// @return outputId returns the unique output identifier of the L2 to L1 tx or 0 if no L2 to L1 transaction is active
     function l2ToL1OutputId() external view returns (bytes32);
 
-    function processOutgoingMessages(bytes calldata sendsData, uint256[] calldata sendLengths) external;
+    /**
+     * @notice Executes a messages in an Outbox entry.
+     * @dev Reverts if dispute period hasn't expired, since the outbox entry
+     *      is only created once the rollup confirms the respective assertion.
+     * @dev it is not possible to execute any L2-to-L1 transaction which contains data
+     *      to a contract address without any code (as enforced by the Bridge contract).
+     * @param proof Merkle proof of message inclusion in send root
+     * @param index Merkle path to message
+     * @param l2Sender sender if original message (i.e., caller of ArbSys.sendTxToL1)
+     * @param to destination address for L1 contract call
+     * @param l2Block l2 block number at which sendTxToL1 call was made
+     * @param l1Block l1 block number at which sendTxToL1 call was made
+     * @param l2Timestamp l2 Timestamp at which sendTxToL1 call was made
+     * @param value wei in L1 message
+     * @param data abi-encoded L1 message data
+     */
+    function executeTransaction(
+        bytes32[] calldata proof,
+        uint256 index,
+        address l2Sender,
+        address to,
+        uint256 l2Block,
+        uint256 l1Block,
+        uint256 l2Timestamp,
+        uint256 value,
+        bytes calldata data
+    ) external;
+
+    /**
+     *  @dev function used to simulate the result of a particular function call from the outbox
+     *       it is useful for things such as gas estimates. This function includes all costs except for
+     *       proof validation (which can be considered offchain as a somewhat of a fixed cost - it's
+     *       not really a fixed cost, but can be treated as so with a fixed overhead for gas estimation).
+     *       We can't include the cost of proof validation since this is intended to be used to simulate txs
+     *       that are included in yet-to-be confirmed merkle roots. The simulation entrypoint could instead pretend
+     *       to confirm a pending merkle root, but that would be less practical for integrating with tooling.
+     *       It is only possible to trigger it when the msg sender is address zero, which should be impossible
+     *       unless under simulation in an eth_call or eth_estimateGas
+     */
+    function executeTransactionSimulation(
+        uint256 index,
+        address l2Sender,
+        address to,
+        uint256 l2Block,
+        uint256 l1Block,
+        uint256 l2Timestamp,
+        uint256 value,
+        bytes calldata data
+    ) external;
+
+    /**
+     * @param index Merkle path to message
+     * @return true if the message has been spent
+     */
+    function isSpent(uint256 index) external view returns (bool);
+
+    function calculateItemHash(
+        address l2Sender,
+        address to,
+        uint256 l2Block,
+        uint256 l1Block,
+        uint256 l2Timestamp,
+        uint256 value,
+        bytes calldata data
+    ) external pure returns (bytes32);
 
-    function outboxEntryExists(uint256 batchNum) external view returns (bool);
+    function calculateMerkleRoot(
+        bytes32[] memory proof,
+        uint256 path,
+        bytes32 item
+    ) external pure returns (bytes32);
 }