Refactor task adding with less locking

src/Worker/WorkerManager.py

@@ -460,12 +460,7 @@ class WorkerManager(object):
                 return 2
         return 0
 
-    # Create new task and return asyncresult
-    def addTask(self, inner_path, peer=None, priority=0, file_info=None):
-        self.lock_add_task.acquire()
-        self.site.onFileStart(inner_path)  # First task, trigger site download started
-        task = self.tasks.findTask(inner_path)
-        if task:  # Already has task for that file
+    def addTaskUpdate(self, task, peer, priority=0):
         if priority > task["priority"]:
             self.tasks.updateItem(task, "priority", priority)
         if peer and task["peers"]:  # This peer also has new version, add it to task possible peers
@@ -476,7 +471,8 @@ class WorkerManager(object):
             task["failed"].remove(peer)  # New update arrived, remove the peer from failed peers
             self.log.debug("Removed peer %s from failed %s" % (peer.key, task["inner_path"]))
             self.startWorkers([peer], reason="Added new task (peer failed before)")
-        else:  # No task for that file yet
+
+    def addTaskCreate(self, inner_path, peer, priority=0, file_info=None):
         evt = gevent.event.AsyncResult()
         if peer:
             peers = [peer]  # Only download from this peer
@@ -492,6 +488,15 @@ class WorkerManager(object):
             size = file_info.get("size", 0)
         else:
             size = 0
+
+        self.lock_add_task.acquire()
+
+        # Check again if we have task for this file
+        task = self.tasks.findTask(inner_path)
+        if task:
+            self.addTaskUpdate(task, peer, priority)
+            return task
+
         priority += self.getPriorityBoost(inner_path)
 
         if self.started_task_num == 0:  # Boost priority for first requested file
@@ -504,6 +509,7 @@ class WorkerManager(object):
         }
 
         self.tasks.append(task)
+        self.lock_add_task.release()
 
         self.next_task_id += 1
         self.started_task_num += 1
@@ -525,7 +531,16 @@ class WorkerManager(object):
 
         else:
             self.startWorkers(peers, reason="Added new task")
-        self.lock_add_task.release()
+        return task
+
+    # Create new task and return asyncresult
+    def addTask(self, inner_path, peer=None, priority=0, file_info=None):
+        self.site.onFileStart(inner_path)  # First task, trigger site download started
+        task = self.tasks.findTask(inner_path)
+        if task:  # Already has task for that file
+            self.addTaskUpdate(task, peer, priority)
+        else:  # No task for that file yet
+            task = self.addTaskCreate(inner_path, peer, priority, file_info)
         return task
 
     def addTaskWorker(self, task, worker):