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Pangolin Process Quality Review
Score: 36%

Overview

This is a Pangolin Process Quality Review completed on June 24th 2021. It was performed using the Process Review process (version 0.7.2) and is documented here. The review was performed by Nic of DeFiSafety. Check out our Telegram.
The final score of the review is 36%, a fail. 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: Avalanche
Guidance: Ethereum Binance Smart Chain Polygon Avalanche

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 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: 70%
They are available at website https://github.com/pangolindex/exchange-contracts as indicated in the Appendix.
Note: gave them a 70% because they direct you to the smart contract address from their core repo in their GitHub. It definitely takes some searching for relatively inexperienced users.
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 labelling not clear or easy to find 0% Executing addresses could not be found

How to improve this score

Make the Ethereum addresses of the smart contract utilized by your application available on either your website or your GitHub (in the README for instance). Ensure the addresses is up to date. This is a very important question wrt to the final score.

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

Answer: 100%
Activity is more than 10 transactions a day on contract Avalanche PangolinRouter.sol, as indicated in the Appendix.

Percentage Score 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 normally test and scripts also (Y/N). Even if the repo was created just to hold the files and has just 1 transaction, it gets a Yes. For teams with private repos, this answer is No.

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

Answer: 0%
With 17 commits and 2 branches in their smart contract repo, this is an unhealthy repository.
This 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 10 commits

How to improve this score

Continue to test and perform other verification activities after deployment, including routine maintenance updating to new releases of testing and deployment tools. A public development history indicates clearly to the public the level of continued investment and activity by the developers on the application. This gives a level of security and faith in the application.

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

Answer: Yes
Team member info can be found at https://www.linkedin.com/company/pangolindex
For a yes in this question the real names of some team members must be public on the website or other documentation. If the team is anonymous and 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: No
No software documentation found.

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

Answer: 0%
Pangolin has API documentation at https://github.com/pangolindex/pangolin-api, but does not state any documentation of their actual smart contract functions anywhere.
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

How to improve this score

This score can improve by adding content to the requirements document such that it comprehensively covers the requirements. For guidance, refer to the SecurEth System Description Document . Using tools that aid traceability detection will help.

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 8% 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: 0%
There was no tracability between any functions and their documentation.
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 requirements to code such that it is clear where each requirement is coded. 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: 40%
Code examples are in the Appendix. As per the SLOC, there is 37% 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

How to improve this score

This score can improve by adding tests to fully cover the code. Document what is covered by traceability or test results in the software repository.

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

Answer: 30%
No test for coverage seen, but some testing evident.
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 improve by adding tests achieving 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

14) Report of the results (%)

Answer: 0%
No test report found in any of their documentation.
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 evidence of a Pangolin Exchange formal verification has been found in their documentation or on the web.

16) Stress Testing environment (%)

Answer: 0%
No evidence of test-net smart contract address usage in any of their documentation.

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: 20%
They have not done any audits because they are a fork of Compound and Uniswap: two very audited protocols.
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, question

18) Is the bounty value acceptably high (%)

Answer: 70%
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
Active program means a third party actively driving hackers to the site. Inactive program would be static mention 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? 2`) 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%
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: 60%
a) Clearly labelled as upgradeable
b) Defined voting roles
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%

How to improve this score

Create a document that covers the items described above. An example is enclosed.

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

Answer: 30%
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

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.

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

Answer: 0%
No Pause Control info in their documentation and no testing evidence found in their GitHub.
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
receive() external payable {
2
assert(msg.sender == WAVAX); // only accept AVAX via fallback from the WAVAX contract
3
}
4
5
// **** ADD LIQUIDITY ****
6
function _addLiquidity(
7
address tokenA,
8
address tokenB,
9
uint amountADesired,
10
uint amountBDesired,
11
uint amountAMin,
12
uint amountBMin
13
) internal virtual returns (uint amountA, uint amountB) {
14
// create the pair if it doesn't exist yet
15
if (IPangolinFactory(factory).getPair(tokenA, tokenB) == address(0)) {
16
IPangolinFactory(factory).createPair(tokenA, tokenB);
17
}
18
(uint reserveA, uint reserveB) = PangolinLibrary.getReserves(factory, tokenA, tokenB);
19
if (reserveA == 0 && reserveB == 0) {
20
(amountA, amountB) = (amountADesired, amountBDesired);
21
} else {
22
uint amountBOptimal = PangolinLibrary.quote(amountADesired, reserveA, reserveB);
23
if (amountBOptimal <= amountBDesired) {
24
require(amountBOptimal >= amountBMin, 'PangolinRouter: INSUFFICIENT_B_AMOUNT');
25
(amountA, amountB) = (amountADesired, amountBOptimal);
26
} else {
27
uint amountAOptimal = PangolinLibrary.quote(amountBDesired, reserveB, reserveA);
28
assert(amountAOptimal <= amountADesired);
29
require(amountAOptimal >= amountAMin, 'PangolinRouter: INSUFFICIENT_A_AMOUNT');
30
(amountA, amountB) = (amountAOptimal, amountBDesired);
31
}
32
}
33
}
34
function addLiquidity(
35
address tokenA,
36
address tokenB,
37
uint amountADesired,
38
uint amountBDesired,
39
uint amountAMin,
40
uint amountBMin,
41
address to,
42
uint deadline
43
) external virtual override ensure(deadline) returns (uint amountA, uint amountB, uint liquidity) {
44
(amountA, amountB) = _addLiquidity(tokenA, tokenB, amountADesired, amountBDesired, amountAMin, amountBMin);
45
address pair = PangolinLibrary.pairFor(factory, tokenA, tokenB);
46
TransferHelper.safeTransferFrom(tokenA, msg.sender, pair, amountA);
47
TransferHelper.safeTransferFrom(tokenB, msg.sender, pair, amountB);
48
liquidity = IPangolinPair(pair).mint(to);
49
}
50
function addLiquidityAVAX(
51
address token,
52
uint amountTokenDesired,
53
uint amountTokenMin,
54
uint amountAVAXMin,
55
address to,
56
uint deadline
57
) external virtual override payable ensure(deadline) returns (uint amountToken, uint amountAVAX, uint liquidity) {
58
(amountToken, amountAVAX) = _addLiquidity(
59
token,
60
WAVAX,
61
amountTokenDesired,
62
msg.value,
63
amountTokenMin,
64
amountAVAXMin
65
);
66
address pair = PangolinLibrary.pairFor(factory, token, WAVAX);
67
TransferHelper.safeTransferFrom(token, msg.sender, pair, amountToken);
68
IWAVAX(WAVAX).deposit{value: amountAVAX}();
69
assert(IWAVAX(WAVAX).transfer(pair, amountAVAX));
70
liquidity = IPangolinPair(pair).mint(to);
71
// refund dust AVAX, if any
72
if (msg.value > amountAVAX) TransferHelper.safeTransferAVAX(msg.sender, msg.value - amountAVAX);
73
}
74
75
// **** REMOVE LIQUIDITY ****
76
function removeLiquidity(
77
address tokenA,
78
address tokenB,
79
uint liquidity,
80
uint amountAMin,
81
uint amountBMin,
82
address to,
83
uint deadline
84
) public virtual override ensure(deadline) returns (uint amountA, uint amountB) {
85
address pair = PangolinLibrary.pairFor(factory, tokenA, tokenB);
86
IPangolinPair(pair).transferFrom(msg.sender, pair, liquidity); // send liquidity to pair
87
(uint amount0, uint amount1) = IPangolinPair(pair).burn(to);
88
(address token0,) = PangolinLibrary.sortTokens(tokenA, tokenB);
89
(amountA, amountB) = tokenA == token0 ? (amount0, amount1) : (amount1, amount0);
90
require(amountA >= amountAMin, 'PangolinRouter: INSUFFICIENT_A_AMOUNT');
91
require(amountB >= amountBMin, 'PangolinRouter: INSUFFICIENT_B_AMOUNT');
92
}
93
function removeLiquidityAVAX(
94
address token,
95
uint liquidity,
96
uint amountTokenMin,
97
uint amountAVAXMin,
98
address to,
99
uint deadline
100
) public virtual override ensure(deadline) returns (uint amountToken, uint amountAVAX) {
101
(amountToken, amountAVAX) = removeLiquidity(
102
token,
103
WAVAX,
104
liquidity,
105
amountTokenMin,
106
amountAVAXMin,
107
address(this),
108
deadline
109
);
110
TransferHelper.safeTransfer(token, to, amountToken);
111
IWAVAX(WAVAX).withdraw(amountAVAX);
112
TransferHelper.safeTransferAVAX(to, amountAVAX);
113
}
114
function removeLiquidityWithPermit(
115
address tokenA,
116
address tokenB,
117
uint liquidity,
118
uint amountAMin,
119
uint amountBMin,
120
address to,
121
uint deadline,
122
bool approveMax, uint8 v, bytes32 r, bytes32 s
123
) external virtual override returns (uint amountA, uint amountB) {
124
address pair = PangolinLibrary.pairFor(factory, tokenA, tokenB);
125
uint value = approveMax ? uint(-1) : liquidity;
126
IPangolinPair(pair).permit(msg.sender, address(this), value, deadline, v, r, s);
127
(amountA, amountB) = removeLiquidity(tokenA, tokenB, liquidity, amountAMin, amountBMin, to, deadline);
128
}
129
function removeLiquidityAVAXWithPermit(
130
address token,
131
uint liquidity,
132
uint amountTokenMin,
133
uint amountAVAXMin,
134
address to,
135
uint deadline,
136
bool approveMax, uint8 v, bytes32 r, bytes32 s
137
) external virtual override returns (uint amountToken, uint amountAVAX) {
138
address pair = PangolinLibrary.pairFor(factory, token, WAVAX);
139
uint value = approveMax ? uint(-1) : liquidity;
140
IPangolinPair(pair).permit(msg.sender, address(this), value, deadline, v, r, s);
141
(amountToken, amountAVAX) = removeLiquidityAVAX(token, liquidity, amountTokenMin, amountAVAXMin, to, deadline);
142
}
143
144
// **** REMOVE LIQUIDITY (supporting fee-on-transfer tokens) ****
145
function removeLiquidityAVAXSupportingFeeOnTransferTokens(
146
address token,
147
uint liquidity,
148
uint amountTokenMin,
149
uint amountAVAXMin,
150
address to,
151
uint deadline
152
) public virtual override ensure(deadline) returns (uint amountAVAX) {
153
(, amountAVAX) = removeLiquidity(
154
token,
155
WAVAX,
156
liquidity,
157
amountTokenMin,
158
amountAVAXMin,
159
address(this),
160
deadline
161
);
162
TransferHelper.safeTransfer(token, to, IERC20(token).balanceOf(address(this)));
163
IWAVAX(WAVAX).withdraw(amountAVAX);
164
TransferHelper.safeTransferAVAX(to, amountAVAX);
165
}
166
function removeLiquidityAVAXWithPermitSupportingFeeOnTransferTokens(
167
address token,
168
uint liquidity,
169
uint amountTokenMin,
170
uint amountAVAXMin,
171
address to,
172
uint deadline,
173
bool approveMax, uint8 v, bytes32 r, bytes32 s
174
) external virtual override returns (uint amountAVAX) {
175
address pair = PangolinLibrary.pairFor(factory, token, WAVAX);
176
uint value = approveMax ? uint(-1) : liquidity;
177
IPangolinPair(pair).permit(msg.sender, address(this), value, deadline, v, r, s);
178
amountAVAX = removeLiquidityAVAXSupportingFeeOnTransferTokens(
179
token, liquidity, amountTokenMin, amountAVAXMin, to, deadline
180
);
181
}
182
183
// **** SWAP ****
184
// requires the initial amount to have already been sent to the first pair
185
function _swap(uint[] memory amounts, address[] memory path, address _to) internal virtual {
186
for (uint i; i < path.length - 1; i++) {
187
(address input, address output) = (path[i], path[i + 1]);
188
(address token0,) = PangolinLibrary.sortTokens(input, output);
189
uint amountOut = amounts[i + 1];
190
(uint amount0Out, uint amount1Out) = input == token0 ? (uint(0), amountOut) : (amountOut, uint(0));
191
address to = i < path.length - 2 ? PangolinLibrary.pairFor(factory, output, path[i + 2]) : _to;
192
IPangolinPair(PangolinLibrary.pairFor(factory, input, output)).swap(
193
amount0Out, amount1Out, to, new bytes(0)
194
);
195
}
196
}
197
function swapExactTokensForTokens(
198
uint amountIn,
199
uint amountOutMin,
200
address[] calldata path,
201
address to,
202
uint deadline
203
) external virtual override ensure(deadline) returns (uint[] memory amounts) {
204
amounts = PangolinLibrary.getAmountsOut(factory, amountIn, path);
205
require(amounts[amounts.length - 1] >= amountOutMin, 'PangolinRouter: INSUFFICIENT_OUTPUT_AMOUNT');
206
TransferHelper.safeTransferFrom(
207
path[0], msg.sender, PangolinLibrary.pairFor(factory, path[0], path[1]), amounts[0]
208
);
209
_swap(amounts, path, to);
210
}
211
function swapTokensForExactTokens(
212
uint amountOut,
213
uint amountInMax,
214
address[] calldata path,
215
address to,
216
uint deadline
217
) external virtual override ensure(deadline) returns (uint[] memory amounts) {
218
amounts = PangolinLibrary.getAmountsIn(factory, amountOut, path);
219
require(amounts[0] <= amountInMax, 'PangolinRouter: EXCESSIVE_INPUT_AMOUNT');
220
TransferHelper.safeTransferFrom(
221
path[0], msg.sender, PangolinLibrary.pairFor(factory, path[0], path[1]), amounts[0]
222
);
223
_swap(amounts, path, to);
224
}
225
function swapExactAVAXForTokens(uint amountOutMin, address[] calldata path, address to, uint deadline)
226
external
227
virtual
228
override
229
payable
230
ensure(deadline)
231
returns (uint[] memory amounts)
232
{
233
require(path[0] == WAVAX, 'PangolinRouter: INVALID_PATH');
234
amounts = PangolinLibrary.getAmountsOut(factory, msg.value, path);
235
require(amounts[amounts.length - 1] >= amountOutMin, 'PangolinRouter: INSUFFICIENT_OUTPUT_AMOUNT');
236
IWAVAX(WAVAX).deposit{value: amounts[0]}();
237
assert(IWAVAX(WAVAX).transfer(PangolinLibrary.pairFor(factory, path[0], path[1]), amounts[0]));
238
_swap(amounts, path, to);
239
}
240
function swapTokensForExactAVAX(uint amountOut, uint amountInMax, address[] calldata path, address to, uint deadline)
241
external
242
virtual
243
override
244
ensure(deadline)
245
returns (uint[] memory amounts)
246
{
247
require(path[path.length - 1] == WAVAX, 'PangolinRouter: INVALID_PATH');
248
amounts = PangolinLibrary.getAmountsIn(factory, amountOut, path);
249
require(amounts[0] <= amountInMax, 'PangolinRouter: EXCESSIVE_INPUT_AMOUNT');
250
TransferHelper.safeTransferFrom(
251
path[0], msg.sender, PangolinLibrary.pairFor(factory, path[0], path[1]), amounts[0]
252
);
253
_swap(amounts, path, address(this));
254
IWAVAX(WAVAX).withdraw(amounts[amounts.length - 1]);
255
TransferHelper.safeTransferAVAX(to, amounts[amounts.length - 1]);
256
}
257
function swapExactTokensForAVAX(uint amountIn, uint amountOutMin, address[] calldata path, address to, uint deadline)
258
external
259
virtual
260
override
261
ensure(deadline)
262
returns (uint[] memory amounts)
263
{
264
require(path[path.length - 1] == WAVAX, 'PangolinRouter: INVALID_PATH');
265
amounts = PangolinLibrary.getAmountsOut(factory, amountIn, path);
266
require(amounts[amounts.length - 1] >= amountOutMin, 'PangolinRouter: INSUFFICIENT_OUTPUT_AMOUNT');
267
TransferHelper.safeTransferFrom(
268
path[0], msg.sender, PangolinLibrary.pairFor(factory, path[0], path[1]), amounts[0]
269
);
270
_swap(amounts, path, address(this));
271
IWAVAX(WAVAX).withdraw(amounts[amounts.length - 1]);
272
TransferHelper.safeTransferAVAX(to, amounts[amounts.length - 1]);
273
}
274
function swapAVAXForExactTokens(uint amountOut, address[] calldata path, address to, uint deadline)
275
external
276
virtual
277
override
278
payable
279
ensure(deadline)
280
returns (uint[] memory amounts)
281
{
282
require(path[0] == WAVAX, 'PangolinRouter: INVALID_PATH');
283
amounts = PangolinLibrary.getAmountsIn(factory, amountOut, path);
284
require(amounts[0] <= msg.value, 'PangolinRouter: EXCESSIVE_INPUT_AMOUNT');
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IWAVAX(WAVAX).deposit{value: amounts[0]}();
286
assert(IWAVAX(WAVAX).transfer(PangolinLibrary.pairFor(factory, path[0], path[1]), amounts[0]));
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_swap(amounts, path, to);
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// refund dust AVAX, if any
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if (msg.value > amounts[0]) TransferHelper.safeTransferAVAX(msg.sender, msg.value - amounts[0]);
290
}
291
292
// **** SWAP (supporting fee-on-transfer tokens) ****
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// requires the initial amount to have already been sent to the first pair
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function _swapSupportingFeeOnTransferTokens(address[] memory path, address _to) internal virtual {
295
for (uint i; i < path.length - 1; i++) {
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(address input, address output) = (path[i], path[i + 1]);
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(address token0,) = PangolinLibrary.sortTokens(input, output);
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IPangolinPair pair = IPangolinPair(PangolinLibrary.pairFor(factory, input, output));
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uint amountInput;
300
uint amountOutput;
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{ // scope to avoid stack too deep errors
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(uint reserve0, uint reserve1,) = pair.getReserves();
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(uint reserveInput, uint reserveOutput) = input == token0 ? (reserve0, reserve1) : (reserve1, reserve0);
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amountInput = IERC20(input).balanceOf(address(pair)).sub(reserveInput);
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amountOutput = PangolinLibrary.getAmountOut(amountInput, reserveInput, reserveOutput);
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}
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(uint amount0Out, uint amount1Out) = input == token0 ? (uint(0), amountOutput) : (amountOutput, uint(0));
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address to = i < path.length - 2 ? PangolinLibrary.pairFor(factory, output, path[i + 2]) : _to;
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pair.swap(amount0Out, amount1Out, to, new bytes(0));
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}
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}
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function swapExactTokensForTokensSupportingFeeOnTransferTokens(
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uint amountIn,
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uint amountOutMin,
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address[] calldata path,
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address to,
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uint deadline
318
) external virtual override ensure(deadline) {
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TransferHelper.safeTransferFrom(
320
path[0], msg.sender, PangolinLibrary.pairFor(factory, path[0], path[1]), amountIn
321
);
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uint balanceBefore = IERC20(path[path.length - 1]).balanceOf(to);
323
_swapSupportingFeeOnTransferTokens(path, to);
324
require(
325
IERC20(path[path.length - 1]).balanceOf(to).sub(balanceBefore) >= amountOutMin,
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'PangolinRouter: INSUFFICIENT_OUTPUT_AMOUNT'
327
);
328
}
329
function swapExactAVAXForTokensSupportingFeeOnTransferTokens(
330
uint amountOutMin,
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address[] calldata path,
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address to,
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uint deadline
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)
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external
336
virtual
337
override
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payable
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ensure(deadline)
340
{
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require(path[0] == WAVAX, 'PangolinRouter: INVALID_PATH');
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uint amountIn = msg.value;
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IWAVAX(WAVAX).deposit{value: amountIn}();
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assert(IWAVAX(WAVAX).transfer(PangolinLibrary.pairFor(factory, path[0], path[1]), amountIn));
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uint balanceBefore = IERC20(path[path.length - 1]).balanceOf(to);
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_swapSupportingFeeOnTransferTokens(path, to);
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require(
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IERC20(path[path.length - 1]).balanceOf(to).sub(balanceBefore) >= amountOutMin,
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'PangolinRouter: INSUFFICIENT_OUTPUT_AMOUNT'
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);
351
}
352
function swapExactTokensForAVAXSupportingFeeOnTransferTokens(
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uint amountIn,
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uint amountOutMin,
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address[] calldata path,
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address to,
357
uint deadline
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)
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external
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virtual
361
override
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ensure(deadline)
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{
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require(path[path.length - 1] == WAVAX, 'PangolinRouter: INVALID_PATH');
365
TransferHelper.safeTransferFrom(
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path[0], msg.sender, PangolinLibrary.pairFor(factory, path[0], path[1]), amountIn
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);
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_swapSupportingFeeOnTransferTokens(path, address(this));
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uint amountOut = IERC20(WAVAX).balanceOf(address(this));
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require(amountOut >= amountOutMin, 'PangolinRouter: INSUFFICIENT_OUTPUT_AMOUNT');
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IWAVAX(WAVAX).withdraw(amountOut);
372
TransferHelper.safeTransferAVAX(to, amountOut);
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}
374
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// **** LIBRARY FUNCTIONS ****
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function quote(uint amountA, uint reserveA, uint reserveB) public pure virtual override returns (uint amountB) {
377
return PangolinLibrary.quote(amountA, reserveA, reserveB);
378
}
379
380
function getAmountOut(uint amountIn, uint reserveIn, uint reserveOut)
381
public
382
pure
383
virtual
384
override
385
returns (uint amountOut)
386
{
387
return PangolinLibrary.getAmountOut(amountIn, reserveIn, reserveOut);
388
}
389
390
function getAmountIn(uint amountOut, uint reserveIn, uint reserveOut)
391
public
392
pure
393
virtual
394
override
395
returns (uint amountIn)
396
{
397
return PangolinLibrary.getAmountIn(amountOut, reserveIn, reserveOut);
398
}
399
400
function getAmountsOut(uint amountIn, address[] memory path)
401
public
402
view
403
virtual
404
override
405
returns (uint[] memory amounts)
406
{
407
return PangolinLibrary.getAmountsOut(factory, amountIn, path);
408
}
409
410
function getAmountsIn(uint amountOut, address[] memory path)
411
public
412
view
413
virtual
414
override
415
returns (uint[] memory amounts)
416
{
417
return PangolinLibrary.getAmountsIn(factory, amountOut, path);
418
}
419
}
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SLOC Appendix

Solidity Contracts

Language
Files
Lines
Blanks
Comments
Code
Complexity
Solidity
23
1650
174
115
1361
146
Comments to Code 115/1361 = 8%

Javascript Tests

Language
Files
Lines
Blanks
Comments
Code
Complexity
JavaScript
11
619
104
18
497
12
Tests to Code 497/1361 = 37%
Last modified 3mo ago