window-props: re-add support for _NET_WM_PID

We will use _NET_WM_PID when xserver does not have XRes extension
or its version is too old.

This partially reverts 9135966673e9fd430b9e8252abdb9c946295e25b.

3 files changed, 30 insertions, 0 deletions

diff --git a/src/core/window-private.h b/src/core/window-private.h
index 67ade36a..ff1a606c 100644
--- a/src/core/window-private.h
+++ b/src/core/window-private.h
@@ -131,6 +131,7 @@ struct _MetaWindow
   char *startup_id;
   char *gtk_theme_variant;
 
+  int net_wm_pid;
   pid_t client_pid;
 
   Window xtransient_for;
diff --git a/src/core/window-props.c b/src/core/window-props.c
index 23b10e29..0b42e569 100644
--- a/src/core/window-props.c
+++ b/src/core/window-props.c
@@ -389,6 +389,28 @@ reload_wm_window_role (MetaWindow    *window,
 }
 
 static void
+reload_net_wm_pid (MetaWindow    *window,
+                   MetaPropValue *value,
+                   gboolean       initial)
+{
+  if (value->type != META_PROP_VALUE_INVALID)
+    {
+      gulong cardinal = (int) value->v.cardinal;
+
+      if (cardinal <= 0)
+        {
+          g_warning ("Application set a bogus _NET_WM_PID %lu", cardinal);
+        }
+      else
+        {
+          window->net_wm_pid = cardinal;
+          meta_verbose ("Window has _NET_WM_PID %d\n",
+                        window->net_wm_pid);
+        }
+    }
+}
+
+static void
 reload_net_wm_user_time (MetaWindow    *window,
                          MetaPropValue *value,
                          gboolean       initial)
@@ -1782,6 +1804,12 @@ meta_display_init_window_prop_hooks (MetaDisplay *display)
       LOAD_INIT | INCLUDE_OR
     },
     {
+      display->atom__NET_WM_PID,
+      META_PROP_VALUE_CARDINAL,
+      reload_net_wm_pid,
+      LOAD_INIT | INCLUDE_OR
+    },
+    {
       XA_WM_NAME,
       META_PROP_VALUE_TEXT_PROPERTY,
       reload_wm_name,
diff --git a/src/core/window.c b/src/core/window.c
index 7933a0f9..1512a18e 100644
--- a/src/core/window.c
+++ b/src/core/window.c
@@ -567,6 +567,7 @@ meta_window_new (MetaDisplay    *display,
   window->startup_id = NULL;
   window->gtk_theme_variant = NULL;
 
+  window->net_wm_pid = -1;
   window->client_pid = -1;
 
   window->xtransient_for = None;