bt2: make it possible to remove a trace class or trace destruction listener

This patch adds the possibility to remove a previously added trace or
trace class destruction listener.  Calling
{_TraceClass,_Trace}.add_destruction_listener returns a
_ListenerHandle.  To remove the listener, the user must pass this handle
back to {_TraceClass,_Trace}.remove_destruction_listener.

Change-Id: I6020135c1e056658d941d2e022b171466c5df7b3
Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Reviewed-on: https://review.lttng.org/c/babeltrace/+/2077
Reviewed-by: Philippe Proulx <eeppeliteloop@gmail.com>

diff --git a/src/bindings/python/bt2/bt2/trace.py b/src/bindings/python/bt2/bt2/trace.py
index b25c8b822a2b1e7a88a1e619a5e68fd2f585f0b2..5dcaa15c422d58f48df913aebf1a4de8717913de 100644 (file)
--- a/src/bindings/python/bt2/bt2/trace.py
+++ b/src/bindings/python/bt2/bt2/trace.py
@@ -178,6 +178,23 @@ class _TraceConst(object._SharedObject, collections.abc.Mapping):
 
         return utils._ListenerHandle(listener_id, self)
 
+    def remove_destruction_listener(self, listener_handle):
+        utils._check_type(listener_handle, utils._ListenerHandle)
+
+        if listener_handle._obj.addr != self.addr:
+            raise ValueError(
+                'This trace destruction listener does not match the trace object.'
+            )
+
+        if listener_handle._listener_id is None:
+            raise ValueError('This trace destruction listener was already removed.')
+
+        status = native_bt.trace_remove_destruction_listener(
+            self._ptr, listener_handle._listener_id
+        )
+        utils._handle_func_status(status)
+        listener_handle._listener_id = None
+
 
 class _Trace(_TraceConst):
     _borrow_stream_ptr_by_id = staticmethod(native_bt.trace_borrow_stream_by_id)

diff --git a/src/bindings/python/bt2/bt2/trace_class.py b/src/bindings/python/bt2/bt2/trace_class.py
index 44a213070b76a0de39884e7ec7d82bd1732f2c8a..9146efacb927b7389857ae189ed7baf8ba18ea57 100644 (file)
--- a/src/bindings/python/bt2/bt2/trace_class.py
+++ b/src/bindings/python/bt2/bt2/trace_class.py
@@ -111,6 +111,25 @@ class _TraceClassConst(object._SharedObject, collections.abc.Mapping):
 
         return utils._ListenerHandle(listener_id, self)
 
+    def remove_destruction_listener(self, listener_handle):
+        utils._check_type(listener_handle, utils._ListenerHandle)
+
+        if listener_handle._obj.addr != self.addr:
+            raise ValueError(
+                'This trace class destruction listener does not match the trace object.'
+            )
+
+        if listener_handle._listener_id is None:
+            raise ValueError(
+                'This trace class destruction listener was already removed.'
+            )
+
+        status = native_bt.trace_class_remove_destruction_listener(
+            self._ptr, listener_handle._listener_id
+        )
+        utils._handle_func_status(status)
+        listener_handle._listener_id = None
+
 
 class _TraceClass(_TraceClassConst):
     _borrow_stream_class_ptr_by_index = staticmethod(

diff --git a/tests/bindings/python/bt2/test_trace.py b/tests/bindings/python/bt2/test_trace.py
index efda9e64ca7a8bd754c4783bb017d1aef8ec4c68..d4dca589367f91978299a52a6119a8de576a794c 100644 (file)
--- a/tests/bindings/python/bt2/test_trace.py
+++ b/tests/bindings/python/bt2/test_trace.py
@@ -24,6 +24,7 @@ from bt2 import trace_class as bt2_trace_class
 from bt2 import value as bt2_value
 from bt2 import trace as bt2_trace
 from bt2 import stream as bt2_stream
+from bt2 import utils as bt2_utils
 
 
 class TraceTestCase(unittest.TestCase):
@@ -144,15 +145,15 @@ class TraceTestCase(unittest.TestCase):
 
     def test_destruction_listener(self):
         def on_trace_class_destruction(trace_class):
-            nonlocal trace_class_destroyed
-            trace_class_destroyed = True
+            nonlocal num_trace_class_destroyed_calls
+            num_trace_class_destroyed_calls += 1
 
         def on_trace_destruction(trace):
-            nonlocal trace_destroyed
-            trace_destroyed = True
+            nonlocal num_trace_destroyed_calls
+            num_trace_destroyed_calls += 1
 
-        trace_destroyed = False
-        trace_class_destroyed = False
+        num_trace_class_destroyed_calls = 0
+        num_trace_destroyed_calls = 0
 
         trace_class = get_default_trace_class()
         stream_class = trace_class.create_stream_class()
@@ -160,30 +161,79 @@ class TraceTestCase(unittest.TestCase):
         stream = trace.create_stream(stream_class)
 
         trace_class.add_destruction_listener(on_trace_class_destruction)
-        trace.add_destruction_listener(on_trace_destruction)
+        td_handle1 = trace.add_destruction_listener(on_trace_destruction)
+        td_handle2 = trace.add_destruction_listener(on_trace_destruction)
 
-        self.assertFalse(trace_class_destroyed)
-        self.assertFalse(trace_destroyed)
+        self.assertIs(type(td_handle1), bt2_utils._ListenerHandle)
+
+        trace.remove_destruction_listener(td_handle2)
+
+        del td_handle1
+        del td_handle2
+
+        self.assertEqual(num_trace_class_destroyed_calls, 0)
+        self.assertEqual(num_trace_destroyed_calls, 0)
 
         del trace
 
-        self.assertFalse(trace_class_destroyed)
-        self.assertFalse(trace_destroyed)
+        self.assertEqual(num_trace_class_destroyed_calls, 0)
+        self.assertEqual(num_trace_destroyed_calls, 0)
 
         del stream
 
-        self.assertFalse(trace_class_destroyed)
-        self.assertTrue(trace_destroyed)
+        self.assertEqual(num_trace_class_destroyed_calls, 0)
+        self.assertEqual(num_trace_destroyed_calls, 1)
 
         del trace_class
 
-        self.assertFalse(trace_class_destroyed)
-        self.assertTrue(trace_destroyed)
+        self.assertEqual(num_trace_class_destroyed_calls, 0)
+        self.assertEqual(num_trace_destroyed_calls, 1)
 
         del stream_class
 
-        self.assertTrue(trace_class_destroyed)
-        self.assertTrue(trace_destroyed)
+        self.assertEqual(num_trace_class_destroyed_calls, 1)
+        self.assertEqual(num_trace_destroyed_calls, 1)
+
+    def test_remove_destruction_listener_wrong_type(self):
+        trace_class = get_default_trace_class()
+        trace = trace_class()
+
+        with self.assertRaisesRegex(
+            TypeError, r"'int' is not a '<class 'bt2.utils._ListenerHandle'>' object"
+        ):
+            trace.remove_destruction_listener(123)
+
+    def test_remove_destruction_listener_wrong_object(self):
+        def on_trace_destruction(trace):
+            pass
+
+        trace_class_1 = get_default_trace_class()
+        trace1 = trace_class_1()
+        trace_class_2 = get_default_trace_class()
+        trace2 = trace_class_2()
+
+        handle1 = trace1.add_destruction_listener(on_trace_destruction)
+
+        with self.assertRaisesRegex(
+            ValueError,
+            r'This trace destruction listener does not match the trace object\.',
+        ):
+            trace2.remove_destruction_listener(handle1)
+
+    def test_remove_destruction_listener_twice(self):
+        def on_trace_destruction(trace_class):
+            pass
+
+        trace_class = get_default_trace_class()
+        trace = trace_class()
+        handle = trace.add_destruction_listener(on_trace_destruction)
+
+        trace.remove_destruction_listener(handle)
+
+        with self.assertRaisesRegex(
+            ValueError, r'This trace destruction listener was already removed\.'
+        ):
+            trace.remove_destruction_listener(handle)
 
 
 if __name__ == '__main__':

diff --git a/tests/bindings/python/bt2/test_trace_class.py b/tests/bindings/python/bt2/test_trace_class.py
index 2acb7fbe54509ca58db0d5cdc78cb1d539d50bce..4c2941da8f5aa1eddc038c5d1b1ce8fd787dcd74 100644 (file)
--- a/tests/bindings/python/bt2/test_trace_class.py
+++ b/tests/bindings/python/bt2/test_trace_class.py
@@ -24,6 +24,7 @@ from utils import (
 )
 from bt2 import stream_class as bt2_stream_class
 from bt2 import trace_class as bt2_trace_class
+from bt2 import utils as bt2_utils
 
 
 class TraceClassTestCase(unittest.TestCase):
@@ -175,19 +176,65 @@ class TraceClassTestCase(unittest.TestCase):
 
     def test_destruction_listener(self):
         def on_trace_class_destruction(trace_class):
-            nonlocal trace_class_destroyed
-            trace_class_destroyed = True
+            nonlocal num_destruct_calls
+            num_destruct_calls += 1
 
-        trace_class_destroyed = False
+        num_destruct_calls = 0
 
         trace_class = get_default_trace_class()
-        trace_class.add_destruction_listener(on_trace_class_destruction)
 
-        self.assertFalse(trace_class_destroyed)
+        handle1 = trace_class.add_destruction_listener(on_trace_class_destruction)
+        self.assertIs(type(handle1), bt2_utils._ListenerHandle)
+
+        handle2 = trace_class.add_destruction_listener(on_trace_class_destruction)
+
+        trace_class.remove_destruction_listener(handle2)
+
+        del handle1
+        del handle2
+
+        self.assertEqual(num_destruct_calls, 0)
 
         del trace_class
 
-        self.assertTrue(trace_class_destroyed)
+        self.assertEqual(num_destruct_calls, 1)
+
+    def test_remove_destruction_listener_wrong_type(self):
+        trace_class = get_default_trace_class()
+
+        with self.assertRaisesRegex(
+            TypeError, r"'int' is not a '<class 'bt2.utils._ListenerHandle'>' object"
+        ):
+            trace_class.remove_destruction_listener(123)
+
+    def test_remove_destruction_listener_wrong_object(self):
+        def on_trace_class_destruction(trace_class):
+            pass
+
+        trace_class_1 = get_default_trace_class()
+        trace_class_2 = get_default_trace_class()
+
+        handle1 = trace_class_1.add_destruction_listener(on_trace_class_destruction)
+
+        with self.assertRaisesRegex(
+            ValueError,
+            r'This trace class destruction listener does not match the trace object\.',
+        ):
+            trace_class_2.remove_destruction_listener(handle1)
+
+    def test_remove_destruction_listener_twice(self):
+        def on_trace_class_destruction(trace_class):
+            pass
+
+        trace_class = get_default_trace_class()
+        handle = trace_class.add_destruction_listener(on_trace_class_destruction)
+
+        trace_class.remove_destruction_listener(handle)
+
+        with self.assertRaisesRegex(
+            ValueError, r'This trace class destruction listener was already removed\.'
+        ):
+            trace_class.remove_destruction_listener(handle)
 
 
 if __name__ == '__main__':