coroutine pool in parallel code

milo/apis/taskRunner.lua

@@ -1,8 +1,31 @@
 local class = require('class')
 
-local parallel = _G.parallel
+local os = _G.os
 
 local TaskRunner = class()
+local free = { }
+
+local function createTask(fn)
+	local task = table.remove(free)
+  if not task then
+    task = {
+      fn = fn,
+      co = coroutine.create(function()
+        local args = { }
+        while true do
+          pcall(task.fn, table.unpack(args))
+          task.dead = true
+          table.insert(free, task)
+          args = { coroutine.yield() }
+        end
+      end)
+    }
+  else
+    task.dead = nil
+    task.fn = fn
+  end
+	return task
+end
 
 function TaskRunner:init(args)
   self.tasks = { }
@@ -14,17 +37,30 @@ function TaskRunner:init(args)
 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)
+  table.insert(self.tasks, createTask(fn))
 end
 
 function TaskRunner:run()
   if #self.tasks > 0 then
-    parallel.waitForAll(table.unpack(self.tasks))
+    local event = { }
+
+    while #self.tasks > 0 do
+      for n = #self.tasks, 1, -1 do
+        local task = self.tasks[n]
+        if task.filter == nil or task.filter == event[1] or event[1] == "terminate" then
+          local ok, param = coroutine.resume(task.co, table.unpack(event))
+          if not ok then
+            self:onError(param)
+          else
+            task.filter = param
+          end
+          if task.dead then
+            table.remove(self.tasks, n)
+          end
+        end
+      end
+      event = { os.pullEventRaw() }
+    end
   end
 end