Remove saturation parameter

Remove saturation parameter, delta, and instead use expansionRate as part of the storage request, in preparation for a linear curve of the expanding window definition.

contracts/Configuration.sol

@@ -6,7 +6,6 @@ import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
 struct MarketplaceConfig {
   CollateralConfig collateral;
   ProofConfig proofs;
-  SlotReservationsConfig reservations;
 }
 
 struct CollateralConfig {
@@ -30,10 +29,3 @@ struct ProofConfig {
   // blocks. Should be a prime number to ensure there are no cycles.
   uint8 downtimeProduct;
 }
-
-struct SlotReservationsConfig {
-  // Percentage of total time before expiry that all addresses are eligible to
-  // reserve a slot. Total time is the duration between request creation and
-  // expiry. Valid range is [0, 99].
-  uint8 saturation;
-}

contracts/FuzzMarketplace.sol

@@ -10,8 +10,7 @@ contract FuzzMarketplace is Marketplace {
     Marketplace(
       MarketplaceConfig(
         CollateralConfig(10, 5, 3, 10),
-        ProofConfig(10, 5, 64, "", 67),
-        SlotReservationsConfig(20)
+        ProofConfig(10, 5, 64, "", 67)
       ),
       new TestToken(),
       new TestVerifier()

contracts/Marketplace.sol

@@ -59,10 +59,7 @@ contract Marketplace is SlotReservations, Proofs, StateRetrieval, Endian {
     MarketplaceConfig memory configuration,
     IERC20 token_,
     IGroth16Verifier verifier
-  )
-    SlotReservations(configuration.reservations)
-    Proofs(configuration.proofs, verifier)
-  {
+  ) Proofs(configuration.proofs, verifier) {
     _token = token_;
 
     require(
@@ -105,8 +102,8 @@ contract Marketplace is SlotReservations, Proofs, StateRetrieval, Endian {
       "maxSlotLoss exceeds slots"
     );
     require(
-      request.expansion > 0 && request.expansion <= 100,
-      "expansion must be [1, 100]"
+      request.expansionRate >= 0 && request.expansionRate <= 100,
+      "expansionRate must be [0, 100]"
     );
 
     _requests[id] = request;

contracts/Requests.sol

@@ -10,10 +10,12 @@ struct Request {
   Content content;
   uint256 expiry; // amount of seconds since start of the request at which this request expires
   bytes32 nonce; // random nonce to differentiate between similar requests
-  // Percentage of addresses eligible to reserve a slot halfway between request
-  // creation and when all network addresses are eligible to participate
-  // (saturation). Acceptable range is [1-100].
-  uint8 expansion;
+  // Percentage of total time before expiry that all addresses are eligible to
+  // reserve a slot. Total time is the duration between request creation and
+  // expiry. Higher number means faster expansion. Valid range is [0, 100],
+  // where 100 means all addresses will be eligible at request creation, and 0
+  // indicates that all addresses will be eligible at the time of expiry.
+  uint8 expansionRate;
 }
 
 struct Ask {

contracts/SlotReservations.sol

@@ -9,15 +9,9 @@ contract SlotReservations {
   using EnumerableSet for EnumerableSet.AddressSet;
 
   mapping(SlotId => EnumerableSet.AddressSet) internal _reservations;
-  SlotReservationsConfig private _config;
 
   uint8 private constant _MAX_RESERVATIONS = 3;
 
-  constructor(SlotReservationsConfig memory config) {
-    require(config.saturation <= 100, "saturation must be [0, 100]");
-    _config = config;
-  }
-
   function reserveSlot(SlotId slotId) public {
     address host = msg.sender;
     require(canReserveSlot(slotId), "Reservation not allowed");

contracts/TestSlotReservations.sol

@@ -6,9 +6,6 @@ import "./SlotReservations.sol";
 contract TestSlotReservations is SlotReservations {
   using EnumerableSet for EnumerableSet.AddressSet;
 
-  // solhint-disable-next-line no-empty-blocks
-  constructor(SlotReservationsConfig memory config) SlotReservations(config) {}
-
   function contains(SlotId slotId, address host) public view returns (bool) {
     return _reservations[slotId].contains(host);
   }

test/Marketplace.test.js

@@ -225,15 +225,10 @@ describe("Marketplace", function () {
       )
     })
 
-    it("is rejected when expansion is out of bounds", async function () {
-      request.expansion = 0
+    it("is rejected when expansionRate is out of bounds", async function () {
+      request.expansionRate = 101
       await expect(marketplace.requestStorage(request)).to.be.revertedWith(
-        "expansion must be [1, 100]"
-      )
-
-      request.expansion = 101
-      await expect(marketplace.requestStorage(request)).to.be.revertedWith(
-        "expansion must be [1, 100]"
+        "expansionRate must be [0, 100]"
       )
     })
 

test/SlotReservations.test.js

@@ -4,7 +4,6 @@ const { exampleRequest } = require("./examples")
 const { requestId, slotId } = require("./ids")
 
 describe("SlotReservations", function () {
-  const saturation = 20
   let reservations
   let provider, address1, address2, address3
   let request
@@ -15,7 +14,7 @@ describe("SlotReservations", function () {
     let SlotReservations = await ethers.getContractFactory(
       "TestSlotReservations"
     )
-    reservations = await SlotReservations.deploy({ saturation })
+    reservations = await SlotReservations.deploy()
     ;[provider, address1, address2, address3] = await ethers.getSigners()
 
     request = await exampleRequest()

test/examples.js

@@ -39,7 +39,9 @@ const exampleRequest = async () => {
     },
     expiry: hours(1),
     nonce: hexlify(randomBytes(32)),
-    expansion: 60, // 60% of nodes are eligible halfway to when all addresses eligible
+    // 60% of the time before expiry, all addresses will be eligible to reserve
+    // slots
+    expansionRate: 60,
   }
 }
 

test/ids.js

@@ -34,7 +34,7 @@ function requestToArray(request) {
       contentToArray(request.content),
       request.expiry,
       request.nonce,
-      request.expansion,
+      request.expansionRate,
     ],
   ]
 }