From f47b66b315ab38c4e786a8d9e73fb8992faab5ba Mon Sep 17 00:00:00 2001
From: Rabindra Harlalka <Rabindra.Harlalka@nice.com>
Date: Wed, 5 Aug 2020 13:06:17 +0530
Subject: [PATCH] Opaque: Drop extra reference when object is un-owned before
 dispose

If the Owned property of a Gst.MiniObject (base class Opaque) is set
from true to false during its lifetime, its reference count is not
decremented.

For example when Gst.Event (derived from Gst.MiniObject) is created
using Gst.Event.NewEos(), Gst.MiniObject.Ref() increments its ref count
and sets Owned = true. Then, passing the event to Gst.Pad.PushEvent(),
sets Owned = false, but this change won't remove the extra reference
that MiniObject.Ref() added earlier and it won't get cleared even when
Unref() gets eventualy called from Dispose(), because
Gst.MiniObject.Unref() only decrements ref count of objects that are
Owned.

This change Unref()s the object when Owned property gets set to false.
---
 Source/glib/Opaque.cs | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/Source/glib/Opaque.cs b/Source/glib/Opaque.cs
index 955285f6a..155416fb9 100644
--- a/Source/glib/Opaque.cs
+++ b/Source/glib/Opaque.cs
@@ -32,6 +32,8 @@ public class Opaque : IWrapper, IDisposable {
 
 		IntPtr _obj;
 		bool owned;
+		bool disposing;
+		bool setOwnedRecursionGuard;
 
 		public static Opaque GetOpaque (IntPtr o, Type type, bool owned)
 		{
@@ -42,7 +44,9 @@ public static Opaque GetOpaque (IntPtr o, Type type, bool owned)
 			if (owned) {
 				if (opaque.owned) {
 					// The constructor took a Ref it shouldn't have, so undo it
+					opaque.setOwnedRecursionGuard = true;
 					opaque.Unref (o);
+					opaque.setOwnedRecursionGuard = false;
 				}
 				opaque.owned = true;
 			} else 
@@ -85,6 +89,7 @@ protected IntPtr Raw {
 
 		public virtual void Dispose ()
 		{
+			disposing = true;
 			Raw = IntPtr.Zero;
 			GC.SuppressFinalize (this);
 		}
@@ -119,6 +124,14 @@ public bool Owned {
 				return owned;
 			}
 			set {
+				// unref if Owned is set to false without disposing this object
+				if (setOwnedRecursionGuard) return;
+				if (owned && !value && _obj != IntPtr.Zero && !disposing) {
+					setOwnedRecursionGuard = true;
+					this.Unref(_obj);
+					setOwnedRecursionGuard = false;
+				}
+
 				owned = value;
 			}
 		}