From 8c6891f1e210424c4b9d257a5194f17f56ae3f26 Mon Sep 17 00:00:00 2001
From: Mark Spanbroek <mark@spanbroek.net>
Date: Tue, 17 Jan 2023 09:05:44 +0100
Subject: [PATCH] [marketplace] slotIsNotFree() modifier

Replaces _slot getter
---
 contracts/Marketplace.sol     | 15 +++++++--------
 contracts/TestMarketplace.sol |  4 ----
 test/Marketplace.test.js      |  8 +-------
 3 files changed, 8 insertions(+), 19 deletions(-)

diff --git a/contracts/Marketplace.sol b/contracts/Marketplace.sol
index db67205..9f9d942 100644
--- a/contracts/Marketplace.sol
+++ b/contracts/Marketplace.sol
@@ -102,8 +102,8 @@ contract Marketplace is Collateral, Proofs, StateRetrieval {
     }
   }
 
-  function freeSlot(SlotId slotId) public {
-    Slot storage slot = _slot(slotId);
+  function freeSlot(SlotId slotId) public slotIsNotFree(slotId) {
+    Slot storage slot = slots[slotId];
     require(slot.host == msg.sender, "Slot filled by other host");
     SlotState state = slotState(slotId);
     require(state != SlotState.Paid, "Already paid");
@@ -133,7 +133,7 @@ contract Marketplace is Collateral, Proofs, StateRetrieval {
   }
 
   function _forciblyFreeSlot(SlotId slotId) internal marketplaceInvariant {
-    Slot storage slot = _slot(slotId);
+    Slot storage slot = slots[slotId];
     RequestId requestId = slot.requestId;
     RequestContext storage context = requestContexts[requestId];
 
@@ -174,7 +174,7 @@ contract Marketplace is Collateral, Proofs, StateRetrieval {
     Request storage request = requests[requestId];
     context.state = RequestState.Finished;
     removeFromMyRequests(request.client, requestId);
-    Slot storage slot = _slot(slotId);
+    Slot storage slot = slots[slotId];
 
     removeFromMySlots(slot.host, slotId);
 
@@ -226,10 +226,9 @@ contract Marketplace is Collateral, Proofs, StateRetrieval {
     return requests[requestId];
   }
 
-  function _slot(SlotId slotId) internal view returns (Slot storage) {
-    Slot storage slot = slots[slotId];
-    require(slot.state != SlotState.Free, "Slot empty");
-    return slot;
+  modifier slotIsNotFree(SlotId slotId) {
+    require(slots[slotId].state != SlotState.Free, "Slot is free");
+    _;
   }
 
   function proofPeriod() public view returns (uint256) {
diff --git a/contracts/TestMarketplace.sol b/contracts/TestMarketplace.sol
index 3815386..2e3a08b 100644
--- a/contracts/TestMarketplace.sol
+++ b/contracts/TestMarketplace.sol
@@ -33,8 +33,4 @@ contract TestMarketplace is Marketplace {
   function forciblyFreeSlot(SlotId slotId) public {
     _forciblyFreeSlot(slotId);
   }
-
-  function slot(SlotId slotId) public view returns (Slot memory) {
-    return _slot(slotId);
-  }
 }
diff --git a/test/Marketplace.test.js b/test/Marketplace.test.js
index 18043a6..52be8db 100644
--- a/test/Marketplace.test.js
+++ b/test/Marketplace.test.js
@@ -297,7 +297,7 @@ describe("Marketplace", function () {
       slot.index = 5
       let nonExistentId = slotId(slot)
       await expect(marketplace.freeSlot(nonExistentId)).to.be.revertedWith(
-        "Slot empty"
+        "Slot is free"
       )
     })
 
@@ -320,12 +320,6 @@ describe("Marketplace", function () {
         .to.emit(marketplace, "SlotFreed")
         .withArgs(slot.request, id)
     })
-
-    it("cannot get slot once freed", async function () {
-      await waitUntilStarted(marketplace, request, proof)
-      await marketplace.freeSlot(id)
-      await expect(marketplace.slot(id)).to.be.revertedWith("Slot empty")
-    })
   })
 
   describe("paying out a slot", function () {