refactor parallel code

milo/apis/taskRunner.lua

@@ -0,0 +1,35 @@
+local class = require('class')
+
+local parallel = _G.parallel
+
+local TaskRunner = class()
+
+function TaskRunner:init(args)
+  self.tasks = { }
+  self.errorMsg = 'Task failed: '
+
+  for k,v in pairs(args or { }) do
+    self[k] = v
+  end
+end
+
+function TaskRunner:add(fn)
+  table.insert(self.tasks, function()
+    local s, m = pcall(fn)
+    if not s and m then
+      self:onError(m)
+    end
+  end)
+end
+
+function TaskRunner:run()
+  if #self.tasks > 0 then
+    parallel.waitForAll(table.unpack(self.tasks))
+  end
+end
+
+function TaskRunner:onError(msg)
+  _G._debug(msg.errorMsg .. msg)
+end
+
+return TaskRunner