Avoid potential null dereferences

As judged by GCC anyway.

3 files changed, 12 insertions, 5 deletions

diff --git a/src/Canvas.cpp b/src/Canvas.cpp
index 6b10128..d86049d 100644
--- a/src/Canvas.cpp
+++ b/src/Canvas.cpp
@@ -312,7 +312,10 @@ disconnect_edge(GanvEdge* edge, void* data)
 {
   auto*       canvas = static_cast<Canvas*>(data);
   Ganv::Edge* edgemm = Glib::wrap(edge);
-  canvas->on_disconnect(edgemm->get_tail(), edgemm->get_head());
+
+  if (canvas && edgemm) {
+    canvas->on_disconnect(edgemm->get_tail(), edgemm->get_head());
+  }
 }
 
 bool
diff --git a/src/Patchage.cpp b/src/Patchage.cpp
index 86d5dbf..7d10abf 100644
--- a/src/Patchage.cpp
+++ b/src/Patchage.cpp
@@ -639,9 +639,11 @@ update_edge_color(GanvEdge* edge, void* data)
   auto*       patchage = static_cast<Patchage*>(data);
   Ganv::Edge* edgemm   = Glib::wrap(edge);
 
-  auto* tail = dynamic_cast<CanvasPort*>((edgemm)->get_tail());
-  if (tail) {
-    edgemm->set_color(patchage->conf().get_port_color(tail->type()));
+  if (edgemm) {
+    auto* tail = dynamic_cast<CanvasPort*>((edgemm)->get_tail());
+    if (tail) {
+      edgemm->set_color(patchage->conf().get_port_color(tail->type()));
+    }
   }
 }
 
diff --git a/src/Reactor.cpp b/src/Reactor.cpp
index 6b141f8..b7458f2 100644
--- a/src/Reactor.cpp
+++ b/src/Reactor.cpp
@@ -89,7 +89,9 @@ Reactor::operator()(const action::DisconnectClient& action)
 {
   if (CanvasModule* mod = find_module(action.client, action.direction)) {
     for (Ganv::Port* p : *mod) {
-      p->disconnect();
+      if (p) {
+        p->disconnect();
+      }
     }
   }
 }