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Cowswap Process Quality Review
Score: 73%

Overview

This is a Cowswap Process Quality Review completed on 23/09/2021. It was performed using the Process Review process (version 0.7.3) and is documented here. The review was performed by Nick of DeFiSafety. Check out our Telegram.
The final score of the review is 73%, a PASS. The breakdown of the scoring is in Scoring Appendix. For our purposes, a pass is 70%.

Summary of the Process

Very simply, the review looks for the following declarations from the developer's site. With these declarations, it is reasonable to trust the smart contracts.
    Here are my smart contracts on the blockchain
    Here is the documentation that explains what my smart contracts do
    Here are the tests I ran to verify my smart contract
    Here are the audit(s) performed on my code by third party experts
    Here are the admin controls and strategies

Disclaimer

This report is for informational purposes only and does not constitute investment advice of any kind, nor does it constitute an offer to provide investment advisory or other services. Nothing in this report shall be considered a solicitation or offer to buy or sell any security, token, future, option or other financial instrument or to offer or provide any investment advice or service to any person in any jurisdiction. Nothing contained in this report constitutes investment advice or offers any opinion with respect to the suitability of any security, and the views expressed in this report should not be taken as advice to buy, sell or hold any security. The information in this report should not be relied upon for the purpose of investing. In preparing the information contained in this report, we have not taken into account the investment needs, objectives and financial circumstances of any particular investor. This information has no regard to the specific investment objectives, financial situation and particular needs of any specific recipient of this information and investments discussed may not be suitable for all investors.
Any views expressed in this report by us were prepared based upon the information available to us at the time such views were written. The views expressed within this report are limited to DeFiSafety and the author and do not reflect those of any additional or third party and are strictly based upon DeFiSafety, its authors, interpretations and evaluation of relevant data. Changed or additional information could cause such views to change. All information is subject to possible correction. Information may quickly become unreliable for various reasons, including changes in market conditions or economic circumstances.
This completed report is copyright (c) DeFiSafety 2021. Permission is given to copy in whole, retaining this copyright label.

Chain

This section indicates the blockchain used by this protocol.
Chain: Ethereum
Guidance: Ethereum Binance Smart Chain Polygon Avalanche Terra

Code and Team

This section looks at the code deployed on the Mainnet that gets reviewed and its corresponding software repository. The document explaining these questions is here. This review will answer the following questions:
1) Are the executing code addresses readily available? (%) 2) Is the code actively being used? (%) 3) Is there a public software repository? (Y/N) 4) Is there a development history visible? (%) 5) Is the team public (not anonymous)? (Y/N)

1) Are the executing code addresses readily available? (%)

Answer: 100%
They are available at website https://github.com/gnosis/gp-v2-contracts/blob/main/networks.json, as indicated in the Appendix. The contracts were located on the bottom left of the front page.
Guidance: 100% Clearly labelled and on website, docs or repo, quick to find 70% Clearly labelled and on website, docs or repo but takes a bit of looking 40% Addresses in mainnet.json, in discord or sub graph, etc 20% Address found but labeling not clear or easy to find 0% Executing addresses could not be found

2) Is the code actively being used? (%)

Answer: 100%
Activity is 400 transactions a day on contract Gnosis Protocol: GPv2Settlement, as indicated in the Appendix.

Guidance:

100% More than 10 transactions a day 70% More than 10 transactions a week 40% More than 10 transactions a month 10% Less than 10 transactions a month 0% No activity

3) Is there a public software repository? (Y/N)

Answer: Yes
Is there a public software repository with the code at a minimum, but also normally test and scripts. Even if the repository was created just to hold the files and has just 1 transaction, it gets a "Yes". For teams with private repositories, this answer is "No".

4) Is there a development history visible? (%)

Answer: 100%
With 1712 commits and 72 branches, Cowswap's development history is beautifully rich and detailed.
This metric checks if the software repository demonstrates a strong steady history. This is normally demonstrated by commits, branches and releases in a software repository. A healthy history demonstrates a history of more than a month (at a minimum).
Guidance: 100% Any one of 100+ commits, 10+branches 70% Any one of 70+ commits, 7+branches 50% Any one of 50+ commits, 5+branches 30% Any one of 30+ commits, 3+branches 0% Less than 2 branches or less than 30 commits

5) Is the team public (not anonymous)? (Y/N)

Answer: Yes
For a "Yes" in this question, the real names of some team members must be public on the website or other documentation (LinkedIn, etc). If the team is anonymous, then this question is a "No".

Documentation

This section looks at the software documentation. The document explaining these questions is here.
Required questions are;
6) Is there a whitepaper? (Y/N) 7) Are the basic software functions documented? (Y/N) 8) Does the software function documentation fully (100%) cover the deployed contracts? (%) 9) Are there sufficiently detailed comments for all functions within the deployed contract code (%) 10) Is it possible to trace from software documentation to the implementation in code (%)

6) Is there a whitepaper? (Y/N)

Answer: Yes

7) Are the basic software functions documented? (Y/N)

Answer: Yes
The documents cover basic software functions.

How to improve this score:

Write the document based on the deployed code. For guidance, refer to the SecurEth System Description Document.

8) Does the software function documentation fully (100%) cover the deployed contracts? (%)

Answer: 100%
The software documentation fully covers both deployed contracts.
Guidance:
100% All contracts and functions documented 80% Only the major functions documented 79-1% Estimate of the level of software documentation 0% No software documentation

9) Are there sufficiently detailed comments for all functions within the deployed contract code (%)

Answer: 0%
Code examples are in the Appendix. As per the SLOC, there is 19% commenting to code (CtC).
The Comments to Code (CtC) ratio is the primary metric for this score.
Guidance: 100% CtC > 100 Useful comments consistently on all code 90-70% CtC > 70 Useful comment on most code 60-20% CtC > 20 Some useful commenting 0% CtC < 20 No useful commenting

How to improve this score

This score can improve by adding comments to the deployed code such that it comprehensively covers the code. For guidance, refer to the SecurEth Software Requirements.

10) Is it possible to trace from software documentation to the implementation in code (%)

Answer: 40%
The Cowswap documentation lists all functions and describes them clearly, but there is no mention of code used in the smart contracts and there is no explicit traceability to their deployment.
Guidance: 100% Clear explicit traceability between code and documentation at a requirement level for all code 60% Clear association between code and documents via non explicit traceability 40% Documentation lists all the functions and describes their functions 0% No connection between documentation and code

How to improve this score:

This score can improve by adding traceability from documentation to code such that it is clear where each outlined function is coded in the source code. For reference, check the SecurEth guidelines on traceability.

Testing

This section looks at the software testing available. It is explained in this document. This section answers the following questions;
11) Full test suite (Covers all the deployed code) (%) 12) Code coverage (Covers all the deployed lines of code, or explains misses) (%) 13) Scripts and instructions to run the tests (Y/N) 14) Report of the results (%) 15) Formal Verification test done (%) 16) Stress Testing environment (%)

11) Is there a Full test suite? (%)

Answer: 100%
Code examples are in the Appendix. As per the SLOC, there is 332% testing to code (TtC).
This score is guided by the Test to Code ratio (TtC). Generally a good test to code ratio is over 100%. However the reviewers best judgement is the final deciding factor.
Guidance: 100% TtC > 120% Both unit and system test visible 80% TtC > 80% Both unit and system test visible 40% TtC < 80% Some tests visible 0% No tests obvious

12) Code coverage (Covers all the deployed lines of code, or explains misses) (%)

Answer: 50%
No code coverage could be found, but given the extremely impressive TtC score it is clear that a significant amount of testing has been undertaken.
Guidance: 100% Documented full coverage 99-51% Value of test coverage from documented results 50% No indication of code coverage but clearly there is a reasonably complete set of tests 30% Some tests evident but not complete 0% No test for coverage seen

How to improve this score:

This score can improved by adding tests that achieve full code coverage. A clear report and scripts in the software repository will guarantee a high score.

13) Scripts and instructions to run the tests (Y/N)

Answer: Yes
Scripts/Instructions location: https://github.com/gnosis/cowswap

14) Report of the results (%)

Answer: 0%
No test report was found.
Guidance: 100% Detailed test report as described below 70% GitHub code coverage report visible 0% No test report evident

How to improve this score

Add a report with the results. The test scripts should generate the report or elements of it.

15) Formal Verification test done (%)

Answer: 0%
No formal verification could be found.

16) Stress Testing environment (%)

Answer: 100%
Cowswap has been deployed to multiple testnets.

Security

This section looks at the 3rd party software audits done. It is explained in this document. This section answers the following questions;
17) Did 3rd Party audits take place? (%) 18) Is the bounty value acceptably high?

17) Did 3rd Party audits take place? (%)

Answer: 70%
One audit was conducted shortly after Cowswap's deployment and while the results are public it is very short at just 3 pages.
Guidance: 100% Multiple Audits performed before deployment and results public and implemented or not required 90% Single audit performed before deployment and results public and implemented or not required 70% Audit(s) performed after deployment and no changes required. Audit report is public
50% Audit(s) performed after deployment and changes needed but not implemented 20% No audit performed 0% Audit Performed after deployment, existence is public, report is not public and no improvements deployed OR smart contract address' not found, (where question 1 is 0%)
Deduct 25% if code is in a private repo and no note from auditors that audit is applicable to deployed code

18) Is the bounty value acceptably high (%)

Answer: 0%
No bug bounty information could be found.
Guidance:
100% Bounty is 10% TVL or at least $1M AND active program (see below) 90% Bounty is 5% TVL or at least 500k AND active program 80% Bounty is 5% TVL or at least 500k 70% Bounty is 100k or over AND active program 60% Bounty is 100k or over 50% Bounty is 50k or over AND active program 40% Bounty is 50k or over 20% Bug bounty program bounty is less than 50k 0% No bug bounty program offered
An active program means that a third party (such as Immunefi) is actively driving hackers to the site. An inactive program would be static mentions on the docs.

Access Controls

This section covers the documentation of special access controls for a DeFi protocol. The admin access controls are the contracts that allow updating contracts or coefficients in the protocol. Since these contracts can allow the protocol admins to "change the rules", complete disclosure of capabilities is vital for user's transparency. It is explained in this document. The questions this section asks are as follow;
19) Can a user clearly and quickly find the status of the admin controls? 20) Is the information clear and complete? 21) Is the information in non-technical terms that pertain to the investments? 22) Is there Pause Control documentation including records of tests?

19) Can a user clearly and quickly find the status of the access controls (%)

Answer: 100%
The documents detailing the planned decentralisation process clearly state the status of access controls.
Guidance: 100% Clearly labelled and on website, docs or repo, quick to find 70% Clearly labelled and on website, docs or repo but takes a bit of looking 40% Access control docs in multiple places and not well labelled 20% Access control docs in multiple places and not labelled 0% Admin Control information could not be found

20) Is the information clear and complete (%)

Answer: 100%
All the contracts are immutable.
Guidance: All the contracts are immutable -- 100% OR
a) All contracts are clearly labelled as upgradeable (or not) -- 30% AND b) The type of ownership is clearly indicated (OnlyOwner / MultiSig / Defined Roles) -- 30% AND c) The capabilities for change in the contracts are described -- 30%

21) Is the information in non-technical terms that pertain to the investments (%)

Answer: 100%
The contracts are immutable, and this is clearly identified.
Guidance: 100% All the contracts are immutable 90% Description relates to investments safety and updates in clear, complete non-software l language 30% Description all in software specific language 0% No admin control information could not be found

22) Is there Pause Control documentation including records of tests (%)

Answer: 0%
No pause control information was found.
Guidance: 100% All the contracts are immutable or no pause control needed and this is explained OR 100% Pause control(s) are clearly documented and there is records of at least one test within 3 months 80% Pause control(s) explained clearly but no evidence of regular tests 40% Pause controls mentioned with no detail on capability or tests 0% Pause control not documented or explained

How to improve this score:

Create a document that covers the items described above in plain language that investors can understand. An example is enclosed.

Appendices

Author Details

The author of this review is Rex of DeFi Safety.
Email : [email protected] Twitter : @defisafety
I started with Ethereum just before the DAO and that was a wonderful education. It showed the importance of code quality. The second Parity hack also showed the importance of good process. Here my aviation background offers some value. Aerospace knows how to make reliable code using quality processes.
I was coaxed to go to EthDenver 2018 and there I started SecuEth.org with Bryant and Roman. We created guidelines on good processes for blockchain code development. We got EthFoundation funding to assist in their development.
Process Quality Reviews are an extension of the SecurEth guidelines that will further increase the quality processes in Solidity and Vyper development.
DeFiSafety is my full time gig and we are working on funding vehicles for a permanent staff.

Scoring Appendix

Executing Code Appendix

Code Used Appendix

Example Code Appendix

1
2
3
constructor(GPv2Authentication authenticator_, IVault vault_) {
4
authenticator = authenticator_;
5
vault = vault_;
6
vaultRelayer = new GPv2VaultRelayer(vault_);
7
}
8
9
// solhint-disable-next-line no-empty-blocks
10
receive() external payable {
11
// NOTE: Include an empty receive function so that the settlement
12
// contract can receive Ether from contract interactions.
13
}
14
15
/// @dev This modifier is called by settle function to block any non-listed
16
/// senders from settling batches.
17
modifier onlySolver {
18
require(authenticator.isSolver(msg.sender), "GPv2: not a solver");
19
_;
20
}
21
22
/// @dev Modifier to ensure that an external function is only callable as a
23
/// settlement interaction.
24
modifier onlyInteraction {
25
require(address(this) == msg.sender, "GPv2: not an interaction");
26
_;
27
}
28
29
/// @dev Settle the specified orders at a clearing price. Note that it is
30
/// the responsibility of the caller to ensure that all GPv2 invariants are
31
/// upheld for the input settlement, otherwise this call will revert.
32
/// Namely:
33
/// - All orders are valid and signed
34
/// - Accounts have sufficient balance and approval.
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/// - Settlement contract has sufficient balance to execute trades. Note
36
/// this implies that the accumulated fees held in the contract can also
37
/// be used for settlement. This is OK since:
38
/// - Solvers need to be authorized
39
/// - Misbehaving solvers will be slashed for abusing accumulated fees for
40
/// settlement
41
/// - Critically, user orders are entirely protected
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///
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/// @param tokens An array of ERC20 tokens to be traded in the settlement.
44
/// Trades encode tokens as indices into this array.
45
/// @param clearingPrices An array of clearing prices where the `i`-th price
46
/// is for the `i`-th token in the [`tokens`] array.
47
/// @param trades Trades for signed orders.
48
/// @param interactions Smart contract interactions split into three
49
/// separate lists to be run before the settlement, during the settlement
50
/// and after the settlement respectively.
51
function settle(
52
IERC20[] calldata tokens,
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uint256[] calldata clearingPrices,
54
GPv2Trade.Data[] calldata trades,
55
GPv2Interaction.Data[][3] calldata interactions
56
) external nonReentrant onlySolver {
57
executeInteractions(interactions[0]);
58
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(
60
GPv2Transfer.Data[] memory inTransfers,
61
GPv2Transfer.Data[] memory outTransfers
62
) = computeTradeExecutions(tokens, clearingPrices, trades);
63
64
vaultRelayer.transferFromAccounts(inTransfers);
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66
executeInteractions(interactions[1]);
67
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vault.transferToAccounts(outTransfers);
69
70
executeInteractions(interactions[2]);
71
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emit Settlement(msg.sender);
73
}
74
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/// @dev Settle an order directly against Balancer V2 pools.
76
///
77
/// @param swaps The Balancer V2 swap steps to use for trading.
78
/// @param tokens An array of ERC20 tokens to be traded in the settlement.
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/// Swaps and the trade encode tokens as indices into this array.
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/// @param trade The trade to match directly against Balancer liquidity. The
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/// order will always be fully executed, so the trade's `executedAmount`
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/// field is used to represent a swap limit amount.
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function swap(
84
IVault.BatchSwapStep[] calldata swaps,
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IERC20[] calldata tokens,
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GPv2Trade.Data calldata trade
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) external nonReentrant onlySolver {
88
RecoveredOrder memory recoveredOrder = allocateRecoveredOrder();
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GPv2Order.Data memory order = recoveredOrder.data;
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recoverOrderFromTrade(recoveredOrder, tokens, trade);
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IVault.SwapKind kind =
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order.kind == GPv2Order.KIND_SELL
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? IVault.SwapKind.GIVEN_IN
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: IVault.SwapKind.GIVEN_OUT;
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IVault.FundManagement memory funds;
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funds.sender = recoveredOrder.owner;
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funds.fromInternalBalance =
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order.sellTokenBalance == GPv2Order.BALANCE_INTERNAL;
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funds.recipient = payable(recoveredOrder.receiver);
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funds.toInternalBalance =
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order.buyTokenBalance == GPv2Order.BALANCE_INTERNAL;
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int256[] memory limits = new int256[](tokens.length);
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uint256 limitAmount = trade.executedAmount;
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// NOTE: Array allocation initializes elements to 0, so we only need to
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// set the limits we care about. This ensures that the swap will respect
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// the order's limit price.
110
if (order.kind == GPv2Order.KIND_SELL) {
111
require(limitAmount >= order.buyAmount, "GPv2: limit too low");
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limits[trade.sellTokenIndex] = order.sellAmount.toInt256();
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limits[trade.buyTokenIndex] = -limitAmount.toInt256();
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} else {
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require(limitAmount <= order.sellAmount, "GPv2: limit too high");
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limits[trade.sellTokenIndex] = limitAmount.toInt256();
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limits[trade.buyTokenIndex] = -order.buyAmount.toInt256();
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}
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GPv2Transfer.Data memory feeTransfer;
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feeTransfer.account = recoveredOrder.owner;
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feeTransfer.token = order.sellToken;
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feeTransfer.amount = order.feeAmount;
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feeTransfer.balance = order.sellTokenBalance;
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int256[] memory tokenDeltas =
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vaultRelayer.batchSwapWithFee(
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kind,
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swaps,
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tokens,
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funds,
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limits,
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// NOTE: Specify a deadline to ensure that an expire order
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// cannot be used to trade.
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order.validTo,
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feeTransfer
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);
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bytes memory orderUid = recoveredOrder.uid;
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uint256 executedSellAmount =
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tokenDeltas[trade.sellTokenIndex].toUint256();
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uint256 executedBuyAmount =
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(-tokenDeltas[trade.buyTokenIndex]).toUint256();
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// NOTE: Check that the orders were completely filled and update their
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// filled amounts to avoid replaying them. The limit price and order
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// validity have already been verified when executing the swap through
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// the `limit` and `deadline` parameters.
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require(filledAmount[orderUid] == 0, "GPv2: order filled");
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if (order.kind == GPv2Order.KIND_SELL) {
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require(
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executedSellAmount == order.sellAmount,
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"GPv2: sell amount not respected"
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);
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filledAmount[orderUid] = order.sellAmount;
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} else {
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require(
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executedBuyAmount == order.buyAmount,
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"GPv2: buy amount not respected"
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);
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filledAmount[orderUid] = order.buyAmount;
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}
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emit Trade(
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recoveredOrder.owner,
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order.sellToken,
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order.buyToken,
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executedSellAmount,
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executedBuyAmount,
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order.feeAmount,
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orderUid
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);
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emit Settlement(msg.sender);
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}
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/// @dev Invalidate onchain an order that has been signed offline.
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///
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/// @param orderUid The unique identifier of the order that is to be made
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/// invalid after calling this function. The user that created the order
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/// must be the the sender of this message. See [`extractOrderUidParams`]
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/// for details on orderUid.
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function invalidateOrder(bytes calldata orderUid) external {
183
(, address owner, ) = orderUid.extractOrderUidParams();
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require(owner == msg.sender, "GPv2: caller does not own order");
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filledAmount[orderUid] = uint256(-1);
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emit OrderInvalidated(owner, orderUid);
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}
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/// @dev Free storage from the filled amounts of **expired** orders to claim
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/// a gas refund. This method can only be called as an interaction.
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///
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/// @param orderUids The unique identifiers of the expired order to free
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/// storage for.
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function freeFilledAmountStorage(bytes[] calldata orderUids)
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external
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onlyInteraction
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{
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freeOrderStorage(filledAmount, orderUids);
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}
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/// @dev Free storage from the pre signatures of **expired** orders to claim
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/// a gas refund. This method can only be called as an interaction.
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///
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/// @param orderUids The unique identifiers of the expired order to free
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/// storage for.
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function freePreSignatureStorage(bytes[] calldata orderUids)
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external
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onlyInteraction
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{
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freeOrderStorage(preSignature, orderUids);
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}
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/// @dev Process all trades one at a time returning the computed net in and
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/// out transfers for the trades.
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///
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/// This method reverts if processing of any single trade fails. See
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/// [`computeTradeExecution`] for more details.
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///
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/// @param tokens An array of ERC20 tokens to be traded in the settlement.
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/// @param clearingPrices An array of token clearing prices.
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/// @param trades Trades for signed orders.
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/// @return inTransfers Array of in transfers of executed sell amounts.
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/// @return outTransfers Array of out transfers of executed buy amounts.
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function computeTradeExecutions(
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IERC20[] calldata tokens,
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uint256[] calldata clearingPrices,
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GPv2Trade.Data[] calldata trades
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)
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internal
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returns (
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GPv2Transfer.Data[] memory inTransfers,
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GPv2Transfer.Data[] memory outTransfers
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)
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{
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RecoveredOrder memory recoveredOrder = allocateRecoveredOrder();
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inTransfers = new GPv2Transfer.Data[](trades.length);
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outTransfers = new GPv2Transfer.Data[](trades.length);
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for (uint256 i = 0; i < trades.length; i++) {
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GPv2Trade.Data calldata trade = trades[i];
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recoverOrderFromTrade(recoveredOrder, tokens, trade);
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computeTradeExecution(
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recoveredOrder,
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clearingPrices[trade.sellTokenIndex],
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clearingPrices[trade.buyTokenIndex],
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trade.executedAmount,
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inTransfers[i],
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outTransfers[i]
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);
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}
253
}
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SLOC Appendix

Solidity Contracts

Language
Files
Lines
Blanks
Comments
Code
Complexity
Solidity
4
1380
69
205
1106
35
Comments to Code 205/1106 = 19%

Javascript Tests

Language
Files
Lines
Blanks
Comments
Code
Complexity
JavaScript
9
4192
479
57
3656
79
TypeScript
1
9
0
0
9
0
Python
1
41
4
29
8
3
Total
11
4242
483
86
3673
82
Tests to Code 3673/1106 = 332%
Last modified 18d ago