libcamera: base: object: Prevent the same signal being connected more than once

Objects are not expected to be connected to the same signal more than
once. Doing so likely indicates a bug in the code, and can be
highlighted in debug builds with an assert that performs a lookup on the
signals_ list.

While it is possible to allow the implementation to let objects connect
to a specific signal multiple times, there are no expected use cases for
this in libcamera and this behaviour is restricted to favour defensive
programming by raising an error when this occurs.

Remove the support in the test framework which uses multiple Signal
connections on the same object, and update the test to use a second
Signal.

Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

1 files changed, 11 insertions, 6 deletions

diff --git a/test/signal.cpp b/test/signal.cpp
index fcf2def1..5c6b304d 100644
--- a/test/signal.cpp
+++ b/test/signal.cpp
@@ -212,17 +212,19 @@ protected:
 		/* ----------------- Signal -> Object tests ----------------- */
 
 		/*
-		 * Test automatic disconnection on object deletion. Connect the
-		 * slot twice to ensure all instances are disconnected.
+		 * Test automatic disconnection on object deletion. Connect two
+		 * signals to ensure all instances are disconnected.
 		 */
 		signalVoid_.disconnect();
+		signalVoid2_.disconnect();
 
 		SlotObject *slotObject = new SlotObject();
 		signalVoid_.connect(slotObject, &SlotObject::slot);
-		signalVoid_.connect(slotObject, &SlotObject::slot);
+		signalVoid2_.connect(slotObject, &SlotObject::slot);
 		delete slotObject;
 		valueStatic_ = 0;
 		signalVoid_.emit();
+		signalVoid2_.emit();
 		if (valueStatic_ != 0) {
 			cout << "Signal disconnection on object deletion test failed" << endl;
 			return TestFail;
@@ -298,17 +300,19 @@ protected:
 		/* --------- Signal -> Object (multiple inheritance) -------- */
 
 		/*
-		 * Test automatic disconnection on object deletion. Connect the
-		 * slot twice to ensure all instances are disconnected.
+		 * Test automatic disconnection on object deletion. Connect two
+		 * signals to ensure all instances are disconnected.
 		 */
 		signalVoid_.disconnect();
+		signalVoid2_.disconnect();
 
 		SlotMulti *slotMulti = new SlotMulti();
 		signalVoid_.connect(slotMulti, &SlotMulti::slot);
-		signalVoid_.connect(slotMulti, &SlotMulti::slot);
+		signalVoid2_.connect(slotMulti, &SlotMulti::slot);
 		delete slotMulti;
 		valueStatic_ = 0;
 		signalVoid_.emit();
+		signalVoid2_.emit();
 		if (valueStatic_ != 0) {
 			cout << "Signal disconnection on object deletion test failed" << endl;
 			return TestFail;
@@ -345,6 +349,7 @@ protected:
 
 private:
 	Signal<> signalVoid_;
+	Signal<> signalVoid2_;
 	Signal<int> signalInt_;
 	Signal<int, const std::string &> signalMultiArgs_;