mapmanager: fixes and some cleanup

resources/[managers]/mapmanager/mapmanager_shared.lua

@@ -1 +1,86 @@
 -- shared logic file for map manager - don't call any subsystem-specific functions here
+mapFiles = {}
+
+function addMap(file, owningResource)
+    if not mapFiles[owningResource] then
+        mapFiles[owningResource] = {}
+    end
+
+    table.insert(mapFiles[owningResource], file)
+end
+
+undoCallbacks = {}
+
+function loadMap(res)
+    if mapFiles[res] then
+        for _, file in ipairs(mapFiles[res]) do
+            parseMap(file, res)
+        end
+    end
+end
+
+function unloadMap(res)
+    if undoCallbacks[res] then
+        for _, cb in ipairs(undoCallbacks[res]) do
+            cb()
+        end
+
+        undoCallbacks[res] = nil
+        mapFiles[res] = nil
+    end
+end
+
+function parseMap(file, owningResource)
+    if not undoCallbacks[owningResource] then
+        undoCallbacks[owningResource] = {}
+    end
+
+    local env = {
+        math = math, pairs = pairs, ipairs = ipairs, next = next, tonumber = tonumber, tostring = tostring,
+        type = type, table = table, string = string, _G = env
+    }
+
+    TriggerEvent('getMapDirectives', function(key, cb, undocb)
+        env[key] = function(...)
+            local state = {}
+
+            state.add = function(k, v)
+                state[k] = v
+            end
+
+            local result = cb(state, ...)
+            local args = table.pack(...)
+
+            table.insert(undoCallbacks[owningResource], function()
+                undocb(state)
+            end)
+
+            return result
+        end
+    end)
+
+    local mt = {
+        __index = function(t, k)
+            if rawget(t, k) ~= nil then return rawget(t, k) end
+
+            -- as we're not going to return nothing here (to allow unknown directives to be ignored)
+            local f = function()
+                return f
+            end
+
+            return function() return f end
+        end
+    }
+
+    setmetatable(env, mt)
+    
+    local fileData = LoadResourceFile(owningResource, file)
+    local mapFunction, err = load(fileData, file, 't', env)
+
+    if not mapFunction then
+        Citizen.Trace("Couldn't load map " .. file .. ": " .. err .. " (type of fileData: " .. type(fileData) .. ")\n")
+        return
+    end
+
+    mapFunction()
+end