Add XFCE Support.

  * Check if XDG_CURRENT_DESKTOP is set to XFCE.
  * Use xfce4-session-logout as logout/reboot/shutdown prompt.
  * Use xfce4-settings-manager for 'Settings...'.
  * Use xflock4 to attept a session lock.
  * Use xfce4-about for info about this computer (not fully
    appropriate but XFCE does not have any appropriate equivalent
    as found in GNOME or MATE).

Fixes AyatanaIndicators/ayatana-indicator-session#1.

3 files changed, 78 insertions, 9 deletions

diff --git a/src/backend-dbus/actions.c b/src/backend-dbus/actions.c
index 84d6600..a8699de 100644
--- a/src/backend-dbus/actions.c
+++ b/src/backend-dbus/actions.c
@@ -94,6 +94,7 @@ typedef enum
   PROMPT_WITH_ZENITY,
   PROMPT_WITH_AYATANA,
   PROMPT_WITH_MATE,
+  PROMPT_WITH_XFCE,
 }
 prompt_status_t;
 
@@ -111,6 +112,19 @@ have_mate_program (const gchar *program)
   return FALSE;
 }
 
+static gboolean
+have_xfce_program (const gchar *program)
+{
+  g_auto(GStrv) desktop_names = NULL;
+
+  if (is_xfce()) {
+    g_autofree gchar *path = g_find_program_in_path (program);
+    return path != NULL;
+  }
+
+  return FALSE;
+}
+
 static prompt_status_t
 get_prompt_status (IndicatorSessionActionsDbus * self)
 {
@@ -123,6 +137,10 @@ get_prompt_status (IndicatorSessionActionsDbus * self)
       if ((prompt == PROMPT_NONE) && have_mate_program ("mate-session-save"))
           prompt = PROMPT_WITH_MATE;
 
+      /* can we use the XFCE prompt? */
+      if ((prompt == PROMPT_NONE) && have_xfce_program ("xfce4-session-logout"))
+          prompt = PROMPT_WITH_XFCE;
+
       /* can we use the Unity/Ayatana prompt? */
       if ((prompt == PROMPT_NONE) && p && p->end_session_dialog)
         {
@@ -809,6 +827,10 @@ my_logout (IndicatorSessionActions * actions)
         run_outside_app ("mate-session-save --logout-dialog");
         break;
 
+      case PROMPT_WITH_XFCE:
+        run_outside_app ("xfce4-session-logout");
+        break;
+
       case PROMPT_NONE:
         logout_now (self);
         break;
@@ -851,6 +873,10 @@ my_reboot (IndicatorSessionActions * actions)
         run_outside_app ("mate-session-save --shutdown-dialog");
         break;
 
+      case PROMPT_WITH_XFCE:
+        run_outside_app ("xfce4-session-logout");
+        break;
+
       case PROMPT_NONE:
         reboot_now (self);
         break;
@@ -888,6 +914,10 @@ my_power_off (IndicatorSessionActions * actions)
         run_outside_app ("mate-session-save --shutdown-dialog");
         break;
 
+      case PROMPT_WITH_XFCE:
+        run_outside_app ("xfce4-session-logout");
+        break;
+
       case PROMPT_WITH_ZENITY:
         if (zenity_question (self,
               "system-shutdown",
@@ -908,15 +938,6 @@ my_power_off (IndicatorSessionActions * actions)
 ****
 ***/
 
-static void
-my_desktop_help (IndicatorSessionActions * self G_GNUC_UNUSED)
-{
-  if (have_mate_program ("yelp"))
-    run_outside_app ("yelp help:mate-user-guide");
-  else
-    run_outside_app ("yelp");
-}
-
 static char *
 find_browser ()
 {
@@ -949,6 +970,24 @@ find_browser ()
 }
 
 static void
+my_desktop_help (IndicatorSessionActions * self G_GNUC_UNUSED)
+{
+  static char * browser = NULL;
+
+  if (have_mate_program ("yelp"))
+    run_outside_app ("yelp help:mate-user-guide");
+  else if (is_xfce())
+    {
+      if (browser == NULL)
+        browser = find_browser();
+      if (browser != NULL)
+        run_outside_app(g_strdup_printf("%s '%s'", browser, "https://docs.xfce.org/"));
+    }
+  else
+    run_outside_app ("yelp");
+}
+
+static void
 my_distro_help (IndicatorSessionActions * self G_GNUC_UNUSED)
 {
   static char * browser = NULL;
@@ -1002,6 +1041,8 @@ my_settings (IndicatorSessionActions * self G_GNUC_UNUSED)
     run_outside_app ("gnome-control-center");
   else if (have_mate_program ("mate-control-center"))
     run_outside_app ("mate-control-center");
+  else if (have_xfce_program ("xfce4-settings-manager"))
+    run_outside_app ("xfce4-settings-manager");
   else
     zenity_warning ("dialog-warning",
                     _("Warning"),
@@ -1030,6 +1071,8 @@ my_about (IndicatorSessionActions * self G_GNUC_UNUSED)
     run_outside_app ("gnome-control-center info");
   else if (have_mate_program ("mate-system-monitor"))
     run_outside_app ("mate-system-monitor --show-system-tab");
+  else if (have_xfce_program ("xfce4-about"))
+    run_outside_app ("xfce4-about");
   else
     zenity_warning ("dialog-warning",
                     _("Warning"),
@@ -1060,6 +1103,10 @@ lock_current_session (IndicatorSessionActions * self, gboolean immediate)
     {
       run_outside_app ("mate-screensaver-command --lock");
     }
+  else if (have_xfce_program ("xflock4"))
+    {
+      run_outside_app ("xflock4");
+    }
   else
     {
       g_return_if_fail (p->screen_saver != NULL);
diff --git a/src/utils.c b/src/utils.c
index 4bc6d68..dad9354 100644
--- a/src/utils.c
+++ b/src/utils.c
@@ -79,6 +79,27 @@ is_mate ()
   return FALSE;
 }
 
+gboolean
+is_xfce ()
+{
+  const gchar *xdg_current_desktop;
+  gchar **desktop_names;
+  int i;
+
+  xdg_current_desktop = g_getenv ("XDG_CURRENT_DESKTOP");
+  if (xdg_current_desktop != NULL) {
+    desktop_names = g_strsplit (xdg_current_desktop, ":", 0);
+    for (i = 0; desktop_names[i]; ++i) {
+      if (!g_strcmp0 (desktop_names[i], "XFCE")) {
+        g_strfreev (desktop_names);
+        return TRUE;
+      }
+    }
+    g_strfreev (desktop_names);
+  }
+  return FALSE;
+}
+
 GHashTable*
 get_os_release (void)
 {
diff --git a/src/utils.h b/src/utils.h
index bb9e750..69bf2c6 100644
--- a/src/utils.h
+++ b/src/utils.h
@@ -23,6 +23,7 @@
 gboolean is_unity();
 gboolean is_gnome();
 gboolean is_mate();
+gboolean is_xfce();
 
 const char* get_distro_name();
 const char* get_distro_url();