Cache unique database stat sort values

spec/System/TestItemDBControl_spec.lua

@@ -62,6 +62,56 @@ describe("ItemDBControl", function()
 		assert.are.equal(-math.huge, invalidItem.measuredPower)
 	end)
 
+	it("reuses unique stat values until relevant build state changes", function()
+		local calcCount = 0
+		local item = {
+			name = "Test Item",
+			base = { },
+			enchantModLines = { },
+			implicitModLines = { },
+			explicitModLines = { },
+			baseModList = { },
+		}
+		local itemsTab = {
+			activeItemSet = { useSecondWeaponSet = false },
+			slots = { ["Body Armour"] = { } },
+			build = {
+				outputRevision = 1,
+				characterLevel = 100,
+				calcsTab = {
+					mainOutput = { Str = 100, Dex = 100, Int = 100 },
+					GetMiscCalculator = function()
+						return function()
+							calcCount = calcCount + 1
+							return { TotalDPS = calcCount }
+						end
+					end,
+				},
+			},
+			IsItemValidForSlot = function()
+				return true
+			end,
+		}
+		local control = new("ItemDBControl"):ItemDBControl(nil, { 0, 0, 100, 100 }, itemsTab, { list = { item } }, "UNIQUE")
+		control.sortDetail = { stat = "TotalDPS" }
+		control.sortOrder = { control.sortControl.STAT, control.sortControl.NAME }
+
+		control:ListBuilder()
+		control:ListBuilder()
+		assert.are.equal(1, calcCount)
+		assert.are.equal(1, item.measuredPower)
+
+		itemsTab.build.outputRevision = 2
+		control:ListBuilder()
+		assert.are.equal(2, calcCount)
+		assert.are.equal(2, item.measuredPower)
+
+		itemsTab.activeItemSet.useSecondWeaponSet = true
+		control:ListBuilder()
+		assert.are.equal(3, calcCount)
+		assert.are.equal(3, item.measuredPower)
+	end)
+
 	it("searches Foulborn modifier text without case sensitivity", function()
 		local item = new("Item"):Item([[
 			Rarity: Unique

src/Classes/ItemDBControl.lua

@@ -256,15 +256,33 @@ function ItemDBClass:ListBuilder()
 		local useFullDPS = self.sortDetail.stat == "FullDPS"
 		local start = GetTime()
 		local calcFunc, calcBase = self.itemsTab.build.calcsTab:GetMiscCalculator(self.build)
+		local statCache
+		if self.dbType == "UNIQUE" then
+			local outputRevision = self.itemsTab.build.outputRevision
+			if self.statCacheOutputRevision ~= outputRevision then
+				self.statCache = { }
+				self.statCacheOutputRevision = outputRevision
+			end
+			local cacheKey = self.sortDetail.stat..":"..(self.itemsTab.activeItemSet.useSecondWeaponSet and "2" or "1")
+			self.statCache = self.statCache or { }
+			self.statCache[cacheKey] = self.statCache[cacheKey] or { }
+			statCache = self.statCache[cacheKey]
+		end
 		for itemIndex, item in ipairs(list) do
-			item.measuredPower = -math.huge
-			for slotName, slot in pairs(self.itemsTab.slots) do
-				if self.itemsTab:IsItemValidForSlot(item, slotName) and not slot.inactive and (not slot.weaponSet or slot.weaponSet == (self.itemsTab.activeItemSet.useSecondWeaponSet and 2 or 1)) then
-					local output = calcFunc(item.base.flask and { toggleFlask = item } or item.base.tincture and { toggleTincture = item } or { repSlotName = slotName, repItem = item }, useFullDPS)
-					local measuredPower = data.powerStatList.GetFromOutput(output, self.sortDetail)
-					item.measuredPower = m_max(item.measuredPower, measuredPower)
+			local measuredPower = statCache and statCache[item]
+			if measuredPower == nil then
+				measuredPower = -math.huge
+				for slotName, slot in pairs(self.itemsTab.slots) do
+					if self.itemsTab:IsItemValidForSlot(item, slotName) and not slot.inactive and (not slot.weaponSet or slot.weaponSet == (self.itemsTab.activeItemSet.useSecondWeaponSet and 2 or 1)) then
+						local output = calcFunc(item.base.flask and { toggleFlask = item } or item.base.tincture and { toggleTincture = item } or { repSlotName = slotName, repItem = item }, useFullDPS)
+						measuredPower = m_max(measuredPower, data.powerStatList.GetFromOutput(output, self.sortDetail))
+					end
+				end
+				if statCache then
+					statCache[item] = measuredPower
 				end
 			end
+			item.measuredPower = measuredPower
 			local now = GetTime()
 			if now - start > 50 then
 				self.defaultText = "^7Sorting... ("..m_floor(itemIndex/#list*100).."%)"