From 0c84ea6d71bc30ee2aa7f61c6502ea379cc51960 Mon Sep 17 00:00:00 2001
From: Edgar Thier <edgar.thier@theimagingsource.com>
Date: Fri, 16 Dec 2022 08:56:44 +0100
Subject: [PATCH] gst: Fix device lost notification handling for closed devices

---
 src/CaptureDeviceImpl.cpp                    |  2 ++
 src/gstreamer-1.0/tcamsrc/gsttcammainsrc.cpp | 15 +++++++++++++++
 2 files changed, 17 insertions(+)

diff --git a/src/CaptureDeviceImpl.cpp b/src/CaptureDeviceImpl.cpp
index fede17c2e..ebab9044c 100644
--- a/src/CaptureDeviceImpl.cpp
+++ b/src/CaptureDeviceImpl.cpp
@@ -87,6 +87,8 @@ CaptureDeviceImpl::~CaptureDeviceImpl()
 
     available_output_formats_.clear();
 
+    index_.remove_device_lost(deviceindex_lost_cb);
+
     device_.reset();
 }
 
diff --git a/src/gstreamer-1.0/tcamsrc/gsttcammainsrc.cpp b/src/gstreamer-1.0/tcamsrc/gsttcammainsrc.cpp
index f0e00dfbd..122fed108 100644
--- a/src/gstreamer-1.0/tcamsrc/gsttcammainsrc.cpp
+++ b/src/gstreamer-1.0/tcamsrc/gsttcammainsrc.cpp
@@ -341,6 +341,19 @@ static void gst_tcam_mainsrc_device_lost_callback(const tcam::tcam_device_info*
 {
     GstTcamMainSrc* self = (GstTcamMainSrc*)user_data;
 
+    GstState state;
+
+    // wait for 1 seconds max
+    gst_element_get_state(GST_ELEMENT(self), &state, nullptr, 1000000000);
+
+    if (!self->device || state == GST_STATE_NULL)
+    {
+        // device does not exist
+        // or source is null (aka no device exists)
+        // do nothing
+        return;
+    }
+
     if (!self->device->is_streaming_)
     {
         return;
@@ -386,6 +399,8 @@ static bool gst_tcam_mainsrc_init_camera(GstTcamMainSrc* self)
         return false;
     }
 
+    // this cb will automatically be deleted once the device is closed
+    // no need for explicit cleanup
     self->device->device_->register_device_lost_callback(gst_tcam_mainsrc_device_lost_callback,
                                                          self);