ChainlinkPriceFeeds

Title: ChainlinkPriceFeeds

Author: 0xJem

Provides prices derived from Chainlink price feed(s)

Constants

BASE_10_MAX_EXPONENT

Any token or pool with a decimal scale greater than this would result in an overflow

uint8 internal constant BASE_10_MAX_EXPONENT = 50;

ONE_FEED_PARAMS_LENGTH

The expected length of the encoded one feed parameters (address + uint48 = 64 bytes)

uint256 internal constant ONE_FEED_PARAMS_LENGTH = 64;

TWO_FEED_PARAMS_LENGTH

The expected length of the encoded two feed parameters (2x address + 2x uint48 = 128 bytes)

uint256 internal constant TWO_FEED_PARAMS_LENGTH = 128;

Functions

constructor

constructor(Module parent_) Submodule(parent_);

Parameters

Name	Type	Description
parent_	`Module`

SUBKEYCODE

20 byte identifier for the submodule. First 5 bytes must match PARENT().

function SUBKEYCODE() public pure override returns (SubKeycode);

Returns

Name	Type	Description
<none>	`SubKeycode`

VERSION

Returns the version of the contract

function VERSION() public pure override returns (uint8 major, uint8 minor);

Returns

Name	Type	Description
major	`uint8`	- Major version upgrade indicates breaking change to the interface.
minor	`uint8`	- Minor version change retains backward-compatible interface.

_validatePriceFeedResult

Validates the result of the price feed

This function will revert if:
Answer <= 0
Updated at timestamp before the update threshold from the current time

function _validatePriceFeedResult(
        AggregatorV2V3Interface feed_,
        FeedRoundData memory roundData,
        uint256 blockTimestamp,
        uint256 paramsUpdateThreshold
    ) internal pure;

Parameters

Name	Type	Description
feed_	`AggregatorV2V3Interface`	Chainlink price feed
roundData	`FeedRoundData`	The round data returned by the price feed
blockTimestamp	`uint256`	The current block timestamp
paramsUpdateThreshold	`uint256`	The maximum number of seconds elapsed since the last price feed update

_getFeedPrice

Retrieves the latest price returned by the specified Chainlink price feed.

The result is validated using _validatePriceFeedResult, and will revert if invalid

function _getFeedPrice(
        AggregatorV2V3Interface feed_,
        uint256 updateThreshold_,
        uint8 feedDecimals_,
        uint8 outputDecimals_
    ) internal view returns (uint256);

Parameters

Name	Type	Description
feed_	`AggregatorV2V3Interface`	Chainlink price feed
updateThreshold_	`uint256`	The maximum number of seconds elapsed since the last price feed update
feedDecimals_	`uint8`	The number of decimals of the price feed
outputDecimals_	`uint8`	The number of decimals to return the price in

Returns

Name	Type	Description
<none>	`uint256`	uint256 The validated price in the scale of `outputDecimals_`

getOneFeedPrice

Returns the price from a single Chainlink feed, as specified in params_.

This function will revert if:
PRICE's priceDecimals or the feed's decimals are out of bounds and would lead to an overflow
The price feed's results are invalid

function getOneFeedPrice(
        address,
        uint8 outputDecimals_,
        bytes calldata params_
    ) external view returns (uint256);

Parameters

Name	Type	Description
_	`address`
outputDecimals_	`uint8`	The number of output decimals (assumed to be the same as PRICE decimals)
params_	`bytes`	Chainlink pool parameters of type `OneFeedParams`

Returns

Name	Type	Description
<none>	`uint256`	uint256 Price in the scale of `outputDecimals_`

getTwoFeedPriceDiv

Returns the result of dividing the price from the first Chainlink feed by the price from the second.

For example, passing in ETH-DAI and USD-DAI will return the ETH-USD price.
This function will revert if:
PRICE's priceDecimals or any of the feed's decimals are out of bounds and would lead to an overflow
Any of the price feeds' results are invalid

function getTwoFeedPriceDiv(
        address,
        uint8 outputDecimals_,
        bytes calldata params_
    ) external view returns (uint256);

Parameters

Name	Type	Description
_	`address`
outputDecimals_	`uint8`	The number of output decimals (assumed to be the same as PRICE decimals)
params_	`bytes`	Chainlink pool parameters of type `TwoFeedParams`

Returns

Name	Type	Description
<none>	`uint256`	uint256 Price in the scale of `outputDecimals_`

getTwoFeedPriceMul

Returns the result of multiplying the price from the first Chainlink feed by the price from the second.

For example, passing in ETH-DAI and DAI-USD will return the ETH-USD price.
This function will revert if:
PRICE's priceDecimals or any of the feed's decimals are out of bounds and would lead to an overflow
Any of the price feeds' results are invalid

function getTwoFeedPriceMul(
        address,
        uint8 outputDecimals_,
        bytes calldata params_
    ) external view returns (uint256);

Parameters

Name	Type	Description
_	`address`
outputDecimals_	`uint8`	The number of output decimals (assumed to be the same as PRICE decimals)
params_	`bytes`	Chainlink pool parameters of type `TwoFeedParams`

Returns

Name	Type	Description
<none>	`uint256`	uint256 Price in the scale of `outputDecimals_`

Errors

Chainlink_ParamsInvalid

The provided parameters are invalid

error Chainlink_ParamsInvalid(bytes params_);

Parameters

Name	Type	Description
params_	`bytes`	The encoded parameters

Chainlink_FeedDecimalsOutOfBounds

The number of decimals of the price feed is greater than the maximum allowed

error Chainlink_FeedDecimalsOutOfBounds(address feed_, uint8 feedDecimals_, uint8 maxDecimals_);

Parameters

Name	Type	Description
feed_	`address`	The address of the price feed
feedDecimals_	`uint8`	The number of decimals of the price feed
maxDecimals_	`uint8`	The maximum number of decimals allowed

Chainlink_FeedPriceInvalid

The price returned by the price feed is invalid

This could be because:
The price is <= 0

error Chainlink_FeedPriceInvalid(address feed_, int256 price_);

Parameters

Name	Type	Description
feed_	`address`	The address of the price feed
price_	`int256`	The price returned by the price feed

Chainlink_FeedRoundStale

The data returned by the price feed is stale

This could be because:
The price feed was last updated before the update threshold

error Chainlink_FeedRoundStale(
        address feed_,
        uint256 roundTimestamp_,
        uint256 thresholdTimestamp_
    );

Parameters

Name	Type	Description
feed_	`address`	The address of the price feed
roundTimestamp_	`uint256`	The timestamp of the round returned by the price feed
thresholdTimestamp_	`uint256`	The earliest acceptable timestamp

Chainlink_ParamsFeedInvalid

A price feed specified in the parameters is invalid

error Chainlink_ParamsFeedInvalid(uint8 paramsIndex_, address feed_);

Parameters

Name	Type	Description
paramsIndex_	`uint8`	The index of the parameter
feed_	`address`	The address of the price feed

Chainlink_ParamsUpdateThresholdInvalid

An update threshold specified in the parameters is invalid

This currently occurs if the update threshold is 0

error Chainlink_ParamsUpdateThresholdInvalid(uint8 paramsIndex_, uint48 updateThreshold_);

Parameters

Name	Type	Description
paramsIndex_	`uint8`	The index of the parameter
updateThreshold_	`uint48`	The update threshold

Chainlink_FeedInvalid

The price feed is invalid

This is triggered if the price feed reverted when called,
and indicates that the feed address is not a Chainlink price feed.

error Chainlink_FeedInvalid(address feed_);

Parameters

Name	Type	Description
feed_	`address`	The address of the price feed

Chainlink_OutputDecimalsOutOfBounds

The number of decimals to return the price in is greater than the maximum allowed

error Chainlink_OutputDecimalsOutOfBounds(uint8 outputDecimals_, uint8 maxDecimals_);

Parameters

Name	Type	Description
outputDecimals_	`uint8`	The number of decimals to return the price in
maxDecimals_	`uint8`	The maximum number of decimals allowed

Structs

OneFeedParams

Parameters for a single Chainlink price feed

struct OneFeedParams {
        AggregatorV2V3Interface feed;
        uint48 updateThreshold;
    }

Properties

Name	Type	Description
feed	`AggregatorV2V3Interface`	Address of the Chainlink price feed
updateThreshold	`uint48`	The maximum number of seconds elapsed since the last price feed update

TwoFeedParams

Parameters for a two Chainlink price feeds

struct TwoFeedParams {
        AggregatorV2V3Interface firstFeed;
        uint48 firstUpdateThreshold;
        AggregatorV2V3Interface secondFeed;
        uint48 secondUpdateThreshold;
    }

Properties

Name	Type	Description
firstFeed	`AggregatorV2V3Interface`	First: Address of the Chainlink price feed
firstUpdateThreshold	`uint48`	First: The maximum number of seconds elapsed since the last price feed update
secondFeed	`AggregatorV2V3Interface`	Second: Address of the Chainlink price feed
secondUpdateThreshold	`uint48`	Second: The maximum number of seconds elapsed since the last price feed update

FeedRoundData

Struct to represent data returned by the Chainlink price feed

struct FeedRoundData {
        uint80 roundId;
        int256 priceInt;
        uint256 startedAt;
        uint256 updatedAt;
    }

Properties

Name	Type	Description
roundId	`uint80`
priceInt	`int256`
startedAt	`uint256`
updatedAt	`uint256`

ChainlinkPriceFeeds

Constants​

BASE_10_MAX_EXPONENT​

ONE_FEED_PARAMS_LENGTH​

TWO_FEED_PARAMS_LENGTH​

Functions​

constructor​

SUBKEYCODE​

VERSION​

_validatePriceFeedResult​

_getFeedPrice​

getOneFeedPrice​

getTwoFeedPriceDiv​

getTwoFeedPriceMul​

Errors​

Chainlink_ParamsInvalid​

Chainlink_FeedDecimalsOutOfBounds​

Chainlink_FeedPriceInvalid​

Chainlink_FeedRoundStale​

Chainlink_ParamsFeedInvalid​

Chainlink_ParamsUpdateThresholdInvalid​

Chainlink_FeedInvalid​

Chainlink_OutputDecimalsOutOfBounds​

Structs​

OneFeedParams​

TwoFeedParams​

FeedRoundData​

Constants

BASE_10_MAX_EXPONENT

ONE_FEED_PARAMS_LENGTH

TWO_FEED_PARAMS_LENGTH

Functions

constructor

SUBKEYCODE

VERSION

_validatePriceFeedResult

_getFeedPrice

getOneFeedPrice

getTwoFeedPriceDiv

getTwoFeedPriceMul

Errors

Chainlink_ParamsInvalid

Chainlink_FeedDecimalsOutOfBounds

Chainlink_FeedPriceInvalid

Chainlink_FeedRoundStale

Chainlink_ParamsFeedInvalid

Chainlink_ParamsUpdateThresholdInvalid

Chainlink_FeedInvalid

Chainlink_OutputDecimalsOutOfBounds

Structs

OneFeedParams

TwoFeedParams

FeedRoundData