MYSO-26: Improve programmatic lender access

[asardon]

Description

Currently, lenders need to keep track of their on-chain quote history with event listeners. However, there aren't any getters to easily access the overall on-chain quote history as well as the overall number of on-chain quotes that were added. This can make deleting open on-chain quotes a bit tedious.

Similarly, there's no function to get return the total number of signers on a vault, hence if a lender wants to know the currently active signers they need to iterate over the signer array.

Recommendation

Add a storage append only array that keeps track of all the added on-chain quote hashes as well as the valid until timestamp. Moreover, add a getter to retrieve the total onchain quote historay length as well as the total number of signers.

[asardon]

Implementation

The append only array for on-chain quote hashes is implemented here:

v2/contracts/peer-to-peer/QuoteHandler.sol

Lines 49 to 55 in 93bf122

	// @dev: on-chain quote history is append only
	onChainQuoteHistory[lenderVault].push(
	DataTypesPeerToPeer.OnChainQuoteInfo({
	quoteHash: onChainQuoteHash,
	validUntil: onChainQuote.generalQuoteInfo.validUntil
	})
	);

The on-chain quote hashes can be retrieved via:

v2/contracts/peer-to-peer/QuoteHandler.sol

Lines 284 to 305 in 93bf122

	function getOnChainQuoteHistory(
	address lenderVault,
	uint256 idx
	) external view returns (DataTypesPeerToPeer.OnChainQuoteInfo memory) {
	if (idx < onChainQuoteHistory[lenderVault].length) {
	return onChainQuoteHistory[lenderVault][idx];
	} else {
	revert Errors.InvalidArrayIndex();
	}
	}
	function getFullOnChainQuoteHistory(
	address lenderVault
	) external view returns (DataTypesPeerToPeer.OnChainQuoteInfo[] memory) {
	return onChainQuoteHistory[lenderVault];
	}
	function getOnChainQuoteHistoryLength(
	address lenderVault
	) external view returns (uint256) {
	return onChainQuoteHistory[lenderVault].length;
	}

The on-chain quote hash history is stored via the following struct which also stores the valid until time to allow lenders to quickly check which on-chain quotes are currently still active:

v2/contracts/peer-to-peer/DataTypesPeerToPeer.sol

Lines 156 to 161 in 93bf122

	struct OnChainQuoteInfo {
	// hash of on chain quote
	bytes32 quoteHash;
	// valid until timestamp
	uint256 validUntil;
	}

[asardon]

Additional Improvements

To minimize the overhead when updating and deleting on-chain quotes, lenders now only need to pass on the quotehash rather than the (old) onChainQuote struct, ie the oldOnChainQuote was removed from the update function:

v2/contracts/peer-to-peer/QuoteHandler.sol

Lines 97 to 99 in 93bf122

	function deleteOnChainQuote(
	address lenderVault,
	bytes32 onChainQuoteHash

and similarly, the onChainQuote struct was removed from the delete function:

v2/contracts/peer-to-peer/QuoteHandler.sol

Lines 97 to 100 in 93bf122

	function deleteOnChainQuote(
	address lenderVault,
	bytes32 onChainQuoteHash
	) external {

Lastly, the number of signers can now be retrieved via:

v2/contracts/peer-to-peer/LenderVaultImpl.sol

Lines 417 to 419 in 93bf122

	function totalNumSigners() external view returns (uint256) {
	return signers.length;
	}