refactor _hasValidAttestation

packages/contracts-periphery/contracts/universal/op-nft/OptimistAllowlist.sol

@@ -65,6 +65,26 @@ contract OptimistAllowlist is Semver {
         OPTIMIST_INVITER = _optimistInviter;
     }
 
+    /**
+     * @notice Checks whether a given address is allowed to mint the Optimist NFT yet. Since the
+     *         Optimist NFT will also be used as part of the Citizens House, mints are currently
+     *         restricted. Eventually anyone will be able to mint.
+     *
+     *         Currently, address is allowed to mint if it satisfies any of the following:
+     *         1) Has a valid 'optimist.can-mint' attestation from the allowlist attestor.
+     *         2) Has a valid 'coinbase.quest-eligible' attestation from Coinbase Quest attestor
+     *         3) Has a valid 'optimist.can-mint-from-invite' attestation from the OptimistInviter
+     *            contract.
+     *
+     * @return Whether or not the address is allowed to mint yet.
+     */
+    function isAllowedToMint(address _claimer) public view returns (bool) {
+        return
+            _hasAttestationFromAllowlistAttestor(_claimer) ||
+            _hasAttestationFromCoinbaseQuestAttestor(_claimer) ||
+            _hasAttestationFromOptimistInviter(_claimer);
+    }
+
     /**
      * @notice Checks whether an address has a valid 'optimist.can-mint' attestation from the
      *         allowlist attestor.
@@ -74,12 +94,9 @@ contract OptimistAllowlist is Semver {
      * @return Whether or not the address has a valid attestation.
      */
     function _hasAttestationFromAllowlistAttestor(address _claimer) internal view returns (bool) {
-        // Expected attestation value is bytes32("true"), but we consider any non-zero value
-        // to be truthy.
+        // Expected attestation value is bytes32("true")
         return
-            ATTESTATION_STATION
-                .attestations(ALLOWLIST_ATTESTOR, _claimer, OPTIMIST_CAN_MINT_ATTESTATION_KEY)
-                .length > 0;
+            _hasValidAttestation(ALLOWLIST_ATTESTOR, _claimer, OPTIMIST_CAN_MINT_ATTESTATION_KEY);
     }
 
     /**
@@ -94,16 +111,13 @@ contract OptimistAllowlist is Semver {
         view
         returns (bool)
     {
-        // Expected attestation value is bytes32("true"), but we consider any non-zero value
-        // to be truthy.
+        // Expected attestation value is bytes32("true")
         return
-            ATTESTATION_STATION
-                .attestations(
+            _hasValidAttestation(
                 COINBASE_QUEST_ATTESTOR,
                 _claimer,
                 COINBASE_QUEST_ELIGIBLE_ATTESTATION_KEY
-                )
-                .length > 0;
+            );
     }
 
     /**
@@ -114,34 +128,30 @@ contract OptimistAllowlist is Semver {
      * @return Whether or not the address has a valid attestation.
      */
     function _hasAttestationFromOptimistInviter(address _claimer) internal view returns (bool) {
-        // Expected attestation value is the inviter's address, but we just check that it's set.
+        // Expected attestation value is the inviter's address
         return
-            ATTESTATION_STATION
-                .attestations(
+            _hasValidAttestation(
                 OPTIMIST_INVITER,
                 _claimer,
                 OptimistConstants.OPTIMIST_CAN_MINT_FROM_INVITE_ATTESTATION_KEY
-                )
-                .length > 0;
+            );
     }
 
     /**
-     * @notice Checks whether a given address is allowed to mint the Optimist NFT yet. Since the
-     *         Optimist NFT will also be used as part of the Citizens House, mints are currently
-     *         restricted. Eventually anyone will be able to mint.
+     * @notice Checks whether an address has a valid truthy attestation.
+     *         Any attestation val other than bytes32("") is considered truthy.
      *
-     *         Currently, address is allowed to mint if it satisfies any of the following:
-     *         1) Has a valid 'optimist.can-mint' attestation from the allowlist attestor.
-     *         2) Has a valid 'coinbase.quest-eligible' attestation from Coinbase Quest attestor
-     *         3) Has a valid 'optimist.can-mint-from-invite' attestation from the OptimistInviter
-     *            contract.
+     * @param _creator Address that made the attestation.
+     * @param _about   Address attestation is about.
+     * @param _key     Key of the attestation.
      *
-     * @return Whether or not the address is allowed to mint yet.
+     * @return Whether or not the address has a valid truthy attestation.
      */
-    function isAllowedToMint(address _claimer) public view returns (bool) {
-        return
-            _hasAttestationFromAllowlistAttestor(_claimer) ||
-            _hasAttestationFromCoinbaseQuestAttestor(_claimer) ||
-            _hasAttestationFromOptimistInviter(_claimer);
+    function _hasValidAttestation(
+        address _creator,
+        address _about,
+        bytes32 _key
+    ) internal view returns (bool) {
+        return ATTESTATION_STATION.attestations(_creator, _about, _key).length > 0;
     }
 }