Implement safe item transactions

itemcontroller.lua

@@ -245,11 +245,14 @@ local PAGES = {
       end,
       function()
         print("Importing...")
-        for _,nodeStack in state.node:find(function(s) return not s:isEmpty() end) do
-          if not state.controller:insertStack(nodeStack) then
-            print("Couldn't find a free slot for: "..(nodeStack:getDisplayName() or nodeStack:getName() or "[EMPTY]"))
+        -- Safely handle transfers, priming computer for a full reset/rescan in case server stops mid-transaction
+        state:itemTransaction(function()
+          for _,nodeStack in state.node:find(function(s) return not s:isEmpty() end) do
+            if not state.controller:insertStack(nodeStack) then
+              print("Couldn't find a free slot for: "..(nodeStack:getDisplayName() or nodeStack:getName() or "[EMPTY]"))
+            end
           end
-        end
+        end)
       end
     )
     state.pageState[state.currentPage] = pageState
@@ -284,9 +287,18 @@ local CONTROLLER_STATE = {
   monitor = monitor,
   nextPage = "MAIN",
   exit = false,
-  pageState = {}
+  pageState = {},
+  lock = lock,
+  unlock = unlock,
+  isLocked = isLocked
 }
 
+function CONTROLLER_STATE:itemTransaction(transact)
+  self.lock()
+  transact()
+  self.unlock()
+end
+
 os.queueEvent("dummy_event")
 while not CONTROLLER_STATE.exit do
   updatePageRender(CONTROLLER_STATE, PAGES)