ChainlinkPriceProvider

Overview

License: MIT

contract ChainlinkPriceProvider is PriceProvider, Initializable, AccessControlUpgradeable

The ChainlinkPriceProvider contract is the contract that provides the functionality for getting the price of a token using Chainlink.

Structs info

ChainlinkMetadata

struct ChainlinkMetadata {
	bool isActive;
	address[] aggregatorPath;
}

Events info

SetTokenAndAggregator

event SetTokenAndAggregator(address indexed token, address[] aggregatorPath)

Emitted when a token and its corresponding Chainlink aggregator path are set.

Parameters:

Name	Type	Description
token	address	The address of the token.
aggregatorPath	address[]	The array of Chainlink aggregator addresses used to get the price of the token.

ChangeActive

event ChangeActive(address indexed token, bool active)

Emitted when the active status of a token is changed.

Parameters:

Name	Type	Description
token	address	The address of the token whose active status is changed.
active	bool	The new active status of the token.

SetTimeOut

event SetTimeOut(address indexed aggregatorPath, uint256 newTimeOut)

Emitted when the time out for a Chainlink aggregator path is set.

Parameters:

Name	Type	Description
aggregatorPath	address	The address of the Chainlink aggregator path.
newTimeOut	uint256	The new time out value in seconds.

SetTokenDecimals

event SetTokenDecimals(uint8 newTokenDecimals)

Emitted when the token decimals is set.

Parameters:

Name	Type	Description
newTokenDecimals	uint8	The new token decimals.

Constants info

MODERATOR_ROLE (0x797669c9)

bytes32 constant MODERATOR_ROLE = keccak256("MODERATOR_ROLE")

DESCRIPTION (0xf1ae8856)

string constant DESCRIPTION = "Price provider that uses chainlink"

MAX_PRICE_PATH_LENGTH (0x01a9a5d3)

uint8 constant MAX_PRICE_PATH_LENGTH = 5

State variables info

tokenDecimals (0x3b97e856)

uint8 tokenDecimals

timeOuts (0x2a6377a9)

mapping(address => uint256) timeOuts

chainlinkMetadata (0x8cc19163)

mapping(address => struct ChainlinkPriceProvider.ChainlinkMetadata) chainlinkMetadata

Modifiers info

onlyModerator

modifier onlyModerator()

Modifier to restrict access to functions to only the contract's moderator.

Functions info

initialize (0x8129fc1c)

function initialize() public initializer

Initializes the contract by setting up the access control roles and assigning them to the contract deployer. The DEFAULT_ADMIN_ROLE and MODERATOR_ROLE roles are set up with the contract deployer as the initial role bearer. decimals is set to 8.

setTokenDecimals (0xf2cf47be)

function setTokenDecimals(uint8 newTokenDecimals) public onlyModerator

Sets the number of decimals used by the token. Only the moderator can call this function.

Parameters:

Name	Type	Description
newTokenDecimals	uint8	The new number of decimals used by the token.

setTimeOut (0x60c74154)

function setTimeOut(
    address aggregatorPath,
    uint256 newTimeOut
) external onlyModerator

Sets the timeout value corresponding to the aggregatorPath.

Example: ETH/USD have a new answer is written when the off-chain data moves more than the 0.5% deviation threshold or 3600 seconds have passed since the last answer was written on-chain. So, the timeOut value for each aggregator will be equal to the heartbeat threshold value plus a period of time to make the transaction update the price, that time period can be 60s or a little more.

Parameters:

Name	Type	Description
aggregatorPath	address	The address of chainlink aggregator contract.
newTimeOut	uint256	It is the amount of time it takes for a new round of aggregation to start after a specified
amount of time since the last update plus a period of time waiting for new price update transactions to execute.

setTokenAndAggregator (0xedc607b0)

function setTokenAndAggregator(
    address token,
    address[] memory aggregatorPath
) public onlyModerator

Set token and aggregator path.

Parameters:

Name	Type	Description
token	address	The address of the token.
aggregatorPath	address[]	The address of the aggregator path.

changeActive (0x258a4532)

function changeActive(address token, bool active) public override onlyModerator

Change active status of token.

Parameters:

Name	Type	Description
token	address	The address of the token.
active	bool	The active status of token.

isListed (0xf794062e)

function isListed(address token) public view override returns (bool)

Returns the is listed status of token.

Parameters:

Name	Type	Description
token	address	the address of token.

Return values:

Name	Type	Description
[0]	bool	isListed the is listed status of token.

isActive (0x9f8a13d7)

function isActive(address token) public view override returns (bool)

Returns the is active status of token.

Parameters:

Name	Type	Description
token	address	the address of token.

Return values:

Name	Type	Description
[0]	bool	isActive the is active status of token.

getLatestPrice (0x16345f18)

function getLatestPrice(
    address aggregatorPath
) public view virtual returns (uint256)

ReturnS the latest price after performing sanity check and staleness check.

Parameters:

Name	Type	Description
aggregatorPath	address	The address of chainlink aggregator contract.

Return values:

Name	Type	Description
[0]	uint256	The latest price (answer).

getPrice (0x41976e09)

function getPrice(
    address token
) public view override returns (uint256 priceMantissa, uint8 priceDecimals)

Returns the latest asset price mantissa and price decimals.

[price] = USD/token

• First step is get priceMantissa with priceDecimals by this formula: price = 1 * 10 ** tokenDecimals * (chainlinkPrice_1 / 10 ** priceDecimals_1) * ... * (chainlinkPrice_n / 10 ** priceDecimals_n) = = 10 ** tokenDecimals (chainlinkPrice_1 * ... * chainlinkPrice_n) / 10 ** (priceDecimals_1 + ... + priceDecimals_n)

• Second step is scale priceMantissa to usdDecimals.

Parameters:

Name	Type	Description
token	address	the token address.

getPriceDecimals (0x1b30aafc)

function getPriceDecimals() public view override returns (uint8)

Returns the number of decimals used for the price provided by the Chainlink oracle.

Return values:

Name	Type	Description
[0]	uint8	The number of decimals used for the price.

getChainlinkMetadata (0xd718fc11)

function getChainlinkMetadata(
    address token
) public view returns (ChainlinkPriceProvider.ChainlinkMetadata memory)

Returns the metadata set up for token.

Parameters:

Name	Type	Description
token	address	The address of the token.

Return values:

Name	Type	Description
[0]	struct ChainlinkPriceProvider.ChainlinkMetadata	metadata The metadata includes active status of token and array of Chainlink aggregator addresses used to get the price of the token.