SellerHandlerFacet Code Style Findings

SHF-01C: Inefficient mapping Lookups

Type	Severity	Location
Gas Optimization		SellerHandlerFacet.sol:L95-L106, L114-L115, L122-L127

Description:

The linked statements perform key-based lookup operations on mapping declarations from storage multiple times for the same key redundantly.

Example:

Copy
113require(
114    protocolLookups().sellerIdByAuthToken[_authToken.tokenType][_authToken.tokenId] == 0 ||
115        protocolLookups().sellerIdByAuthToken[_authToken.tokenType][_authToken.tokenId] == _seller.id,
116    AUTH_TOKEN_MUST_BE_UNIQUE
117);

Recommendation:

As the lookups internally perform an expensive keccak256 operation, we advise the lookups to be cached wherever possible to a single local declaration that either holds the value of the mapping in case of primitive types or holds a storage pointer to the struct contained.

Alleviation (44009967e4f68092941d841e9e0f5dd2bb31bf0b):

The referenced mapping lookups have been optimized to the greatest extent possible thus greatly reducing the gas cost of the codebase.

SHF-02C: Repetitive Invocations of Getter Function

Type	Severity	Location
Gas Optimization		SellerHandlerFacet.sol:L95-L106, L114-L115, L122-L127, L133-L136, L148

Description:

The linked statements repetitively invoke the same getter function whilst its return value remains unchanged.

Example:

Copy
95(protocolLookups().sellerIdByOperator[_seller.operator] == 0 ||
96    protocolLookups().sellerIdByOperator[_seller.operator] == _seller.id) &&
97    (protocolLookups().sellerIdByOperator[_seller.clerk] == 0 ||
98        protocolLookups().sellerIdByOperator[_seller.clerk] == _seller.id) &&
99    (protocolLookups().sellerIdByAdmin[_seller.operator] == 0 ||
100        protocolLookups().sellerIdByAdmin[_seller.operator] == _seller.id) &&
101    (protocolLookups().sellerIdByAdmin[_seller.clerk] == 0 ||
102        protocolLookups().sellerIdByAdmin[_seller.clerk] == _seller.id) &&
103    (protocolLookups().sellerIdByClerk[_seller.operator] == 0 ||
104        protocolLookups().sellerIdByClerk[_seller.operator] == _seller.id) &&
105    (protocolLookups().sellerIdByClerk[_seller.clerk] == 0 ||
106        protocolLookups().sellerIdByClerk[_seller.clerk] == _seller.id),

Recommendation:

We advise the getter function to be invoked once and its result to be stored to a local variable that is consequently utilized optimizing the gas cost of the statements significantly.

Alleviation (44009967e4f68092941d841e9e0f5dd2bb31bf0b):

The protocol lookups are now correctly cached to local variable declarations thus optimizing the codebase's gas cost.