curds: Improve queueing notifications

The UI might take a while to process queued notifications, so to keep
from overwhelming the UI we want to only queue notification that haven't
been added already.

I also add in a lock around the notification queue since the main thread
processes notifications added by other threads.

Signed-off-by: Anna Schumaker <Anna@NoWheyCreamery.com>

curds/notify.py

@@ -1,13 +1,17 @@
 # Copyright 2019 (c) Anna Schumaker.
+import threading
 
 registered = { }
 queued     = [ ]
+lock       = threading.Lock()
 
 def notify(name, *args):
     for (func, queue) in registered.get(name, []):
         if queue == True:
-            queued.append((func, args))
-            notify("task-queued")
+            with lock:
+                if (func, args) not in queued:
+                    queued.append((func, args))
+                    notify("task-queued")
         else:
             func(*args)
 
@@ -25,7 +29,8 @@ def register(name, func, queue=False):
     cb.append((func, queue))
 
 def run_queued():
-    if len(queued) > 0:
-        (func, args) = queued.pop(0)
-        func(*args)
-    return len(queued) > 0
+    with lock:
+        if len(queued) > 0:
+            (func, args) = queued.pop(0)
+            func(*args)
+        return len(queued) > 0

curds/playlist/test_library.py

@@ -14,6 +14,7 @@ class TestLibraryPlaylist(unittest.TestCase):
     def setUp(self):
         library.reset()
         tags.clear()
+        notify.registered.clear()
 
     def tearDownClass():
         library.stop()

curds/test_notify.py

@@ -11,14 +11,16 @@ class TestNotify(unittest.TestCase):
         self.test_arg2   = None
         self.task_queued = False
 
-    def on_test1(self, arg1, arg2):
-        self.test_count += 1
-    def on_test2(self, arg1, arg2):
-        self.test_arg1   = arg1
-    def on_test3(self, arg1, arg2):
-        self.test_arg2   = arg2
-    def on_queued(self):
-        self.task_queued = True
+    def tearDown(self):
+        notify.queued.clear()
+        notify.registered.clear()
+
+    def on_test1(self, arg1, arg2): self.test_count += 1
+    def on_test2(self, arg1, arg2): self.test_arg1   = arg1
+    def on_test3(self, arg1, arg2): self.test_arg2   = arg2
+
+    def on_task_queued(self):      self.task_queued = True
+    def on_test_queue(self, arg1): self.test_count += 1; self.test_arg1 = arg1
 
     def test_notify(self):
         self.assertEqual(notify.registered, {})
@@ -29,17 +31,14 @@ class TestNotify(unittest.TestCase):
         notify.register("on-test", self.on_test1, True)
         notify.register("on-test", self.on_test2)
         notify.register("on-test", self.on_test3, True)
-        notify.register("task-queued", self.on_queued)
         self.assertEqual(notify.registered, {"on-test" : [ (self.on_test1,  False),
                                                            (self.on_test2,  False),
-                                                           (self.on_test3,  True ) ],
-                                         "task-queued" : [ (self.on_queued, False) ]})
+                                                           (self.on_test3,  True ) ]})
 
         notify.notify("on-test", "It Worked", "CoolCoolCool")
         self.assertEqual(self.test_count, 1)
         self.assertEqual(self.test_arg1, "It Worked")
         self.assertEqual(self.test_arg2, None)
-        self.assertTrue(self.task_queued)
 
         self.assertEqual(notify.queued, [ (self.on_test3, ("It Worked", "CoolCoolCool")) ])
         self.assertFalse(notify.run_queued())
@@ -49,8 +48,7 @@ class TestNotify(unittest.TestCase):
         notify.notify("no-cb", "Please", "Don't", "Crash")
         self.assertFalse(notify.run_queued())
 
-        notify.cancel("task-queued", self.on_queued)
-        notify.cancel("on-test",     self.on_test2)
+        notify.cancel("on-test", self.on_test2)
         self.assertEqual(notify.registered, {"on-test" : [ (self.on_test1, False),
                                                            (self.on_test3, True) ]})
         notify.cancel("on-test", self.on_test1)
@@ -59,3 +57,34 @@ class TestNotify(unittest.TestCase):
         self.assertEqual(notify.registered, { })
         notify.cancel("on-test", self.on_test1)
         self.assertEqual(notify.registered, { })
+
+    def test_queue(self):
+        notify.register("task-queued", self.on_task_queued)
+        notify.register("on-test", self.on_test_queue, True)
+
+        self.assertEqual(notify.registered, {"on-test" : [ (self.on_test_queue,  True)  ],
+                                         "task-queued" : [ (self.on_task_queued, False) ]})
+
+        notify.notify("on-test", "Test Bundle")
+        self.assertTrue(self.task_queued)
+        self.assertEqual(notify.queued, [ (self.on_test_queue, ("Test Bundle",)) ])
+
+        self.task_queued = False
+        notify.notify("on-test", "Test Bundle")
+        self.assertFalse(self.task_queued)
+        self.assertEqual(notify.queued, [ (self.on_test_queue, ("Test Bundle",)) ])
+
+        notify.notify("on-test", "Test Bundle 2")
+        self.assertTrue(self.task_queued)
+        self.assertEqual(notify.queued, [ (self.on_test_queue, ("Test Bundle",)),
+                                          (self.on_test_queue, ("Test Bundle 2",)) ])
+
+        self.assertTrue(notify.run_queued())
+        self.assertEqual(self.test_count, 1)
+        self.assertEqual(self.test_arg1, "Test Bundle")
+        self.assertEqual(notify.queued, [ (self.on_test_queue, ("Test Bundle 2",)) ])
+
+        self.assertFalse(notify.run_queued())
+        self.assertEqual(self.test_count, 2)
+        self.assertEqual(self.test_arg1, "Test Bundle 2")
+        self.assertEqual(notify.queued, [ ])