Implement listen cancelling

Signed-off-by: Rahix <rahix@rahix.de>

tests/listening.lua

@@ -134,3 +134,64 @@ do
     end
   end
 end
+
+function test_listen_cancel()
+  local bc = BaseControl:new()
+  bc:register("lcan1", 123)
+  bc:finalize()
+
+  local n = 0
+  local id = bc:listen("lcan1", BaseControl.Query.Change, function()
+    n = n + 1
+  end)
+
+
+  assert_equal(0, n, "wrong number of listener invokations")
+  bc:set("lcan1", 321)
+  assert_equal(1, n, "wrong number of listener invokations")
+
+  -- Cancel the listener
+  bc:cancel("lcan1", id)
+
+  bc:set("lcan1", 12)
+  assert_equal(1, n, "wrong number of listener invokations")
+
+  assert_error_match("unknown", function()
+    bc:cancel("lcan1", id)
+  end)
+
+  assert_error_match("unknown", function()
+    bc:cancel("lcan2", "fooid")
+  end)
+end
+
+function test_listen_cancel_remote()
+  local bc1 = BaseControl:new()
+  local addr1 = network.get_scene()
+  bc1:register("lcanr1", 123)
+  bc1:finalize()
+
+  local bc2 = BaseControl:new()
+  local addr2 = network.get_scene()
+
+  local n = 0
+  local id, ok = bc2:listen("lcanr1", BaseControl.Query.Change, function()
+    n = n + 1
+  end)
+  assert_true(ok, "failed installing")
+
+  network.set_scene(addr1)
+  assert_equal(0, n, "wrong number of listener invokations")
+  bc1:set("lcanr1", 34)
+  assert_equal(1, n, "wrong number of listener invokations")
+
+  -- Dirty hack to get the test working
+  local save = bc2.listeners["lcanr1"][id]
+  network.set_scene(addr2)
+  bc2:cancel("lcanr1", id)
+  bc2.listeners["lcanr1"][id] = save
+
+  network.set_scene(addr1)
+  bc1:set("lcanr1", 21)
+  assert_equal(1, n, "wrong number of listener invokations")
+end