restack: Add bottom restacking strategy

For now this is the same as the generic one

include/utils/restack.hpp

@@ -8,7 +8,12 @@
 POLYBAR_NS
 
 namespace restack_util {
+  using params = std::pair<xcb_window_t, xcb_stack_mode_t>;
+
   void restack_relative(connection& conn, xcb_window_t win, xcb_window_t sibling, xcb_stack_mode_t stack_mode);
+  bool are_siblings(connection& conn, xcb_window_t win, xcb_window_t sibling);
+  params get_bottom_params(connection& conn, xcb_window_t bar_window);
+  params get_generic_params(connection& conn, xcb_window_t bar_window);
 }
 
 POLYBAR_NS_END

src/components/bar.cpp

@@ -480,8 +480,11 @@ void bar::toggle() {
 }
 
 /**
- * Move the bar window above defined sibling
+ * Move the bar window above/below defined sibling in the X window stack.
- * in the X window stack
+ *
+ * How the sibling is determined depends on the wm-restack setting.
+ *
+ * This is meant to resolve polybar appearing above other windows (especially in fullscreen).
  */
 void bar::restack_window() {
   string wm_restack;
@@ -492,15 +495,15 @@ void bar::restack_window() {
     return;
   }
 
+  xcb_window_t bar_window = m_opts.x_data.window;
+
   xcb_window_t restack_sibling = XCB_NONE;
   xcb_stack_mode_t stack_mode = XCB_STACK_MODE_ABOVE;
 
   if (wm_restack == "generic") {
-    auto children = m_connection.query_tree(m_connection.root()).children();
+    std::tie(restack_sibling, stack_mode) = restack_util::get_bottom_params(m_connection, bar_window);
-    if (children.begin() != children.end() && *children.begin() != m_opts.x_data.window) {
+  } else if (wm_restack == "bottom") {
-      restack_sibling = *children.begin();
+    std::tie(restack_sibling, stack_mode) = restack_util::get_bottom_params(m_connection, bar_window);
-      stack_mode = XCB_STACK_MODE_BELOW;
-    }
   } else if (wm_restack == "bspwm") {
     restack_sibling = bspwm_util::get_restack_sibling(m_connection, m_opts.monitor);
 #if ENABLE_I3
@@ -517,13 +520,13 @@ void bar::restack_window() {
 
   if (restack_sibling != XCB_NONE) {
     try {
-      restack_util::restack_relative(m_connection, m_opts.x_data.window, restack_sibling, stack_mode);
+      restack_util::restack_relative(m_connection, bar_window, restack_sibling, stack_mode);
       m_log.info("Successfully restacked bar window");
     } catch (const exception& err) {
       m_log.err("Failed to restack bar window (err=%s)", err.what());
     }
   } else if (!wm_restack.empty()) {
-    m_log.err("Failed to restack bar window");
+    m_log.err("Failed to restack bar window: No suitable sibling window for restacking was found");
   }
 }
 

src/utils/bspwm.cpp

@@ -36,10 +36,7 @@ vector<xcb_window_t> root_windows(connection& conn) {
 }
 
 /**
- * Restack given window relative to the bspwm root window
+ * Returns window against which to restack.
- * for the given monitor.
- *
- * Fixes the issue with always-on-top window's
  */
 xcb_window_t get_restack_sibling(connection& conn, const monitor_t& mon) {
   for (auto&& root : root_windows(conn)) {

src/utils/i3.cpp

@@ -66,10 +66,7 @@ namespace i3_util {
   }
 
   /**
-   * Restack given window relative to the i3 root window
+   * Returns window against which to restack.
-   * defined for the given monitor
-   *
-   * Fixes the issue with always-on-top window's
    */
   xcb_window_t get_restack_sibling(connection& conn) {
     return root_window(conn);

src/utils/restack.cpp

@@ -3,6 +3,9 @@
 POLYBAR_NS
 
 namespace restack_util {
+
+static constexpr params NONE_PARAMS = {XCB_NONE, XCB_STACK_MODE_ABOVE};
+
 /**
  * Restacks the given window relative to a given sibling with some stack order (above, below)
  *
@@ -18,6 +21,51 @@ namespace restack_util {
   const std::array<uint32_t, 2> value_list = {sibling, stack_mode};
   conn.configure_window_checked(win, value_mask, value_list.data());
 }
+
+/**
+ * @return true iff the two given windows are sibings (are different windows and have same parent).
+ */
+bool are_siblings(connection& conn, xcb_window_t win, xcb_window_t sibling) {
+  if (win == XCB_NONE || sibling == XCB_NONE || win == sibling) {
+    return false;
   }
 
+  auto win_tree = conn.query_tree(win);
+  auto sibling_tree = conn.query_tree(sibling);
+  return win_tree->parent == sibling_tree->parent;
+}
+
+/**
+ * "bottom" restack strategy.
+ *
+ * Moves the bar window to the bottom of the window stack
+ */
+std::pair<xcb_window_t, xcb_stack_mode_t> get_bottom_params(connection& conn, xcb_window_t bar_window) {
+  auto children = conn.query_tree(conn.root()).children();
+  if (children.begin() != children.end() && *children.begin() != bar_window) {
+    return {*children.begin(), XCB_STACK_MODE_BELOW};
+  }
+
+  return NONE_PARAMS;
+}
+
+/**
+ * Generic restack stratgey.
+ *
+ * Tries to provide the best WM-agnostic restacking.
+ *
+ * Currently tries to the following stratgies in order:
+ * * bottom
+ */
+std::pair<xcb_window_t, xcb_stack_mode_t> get_generic_params(connection& conn, xcb_window_t bar_window) {
+  auto [sibling, mode] = get_bottom_params(conn, bar_window);
+
+  if (are_siblings(conn, bar_window, sibling)) {
+    return {sibling, mode};
+  }
+
+  return NONE_PARAMS;
+}
+} // namespace restack_util
+
 POLYBAR_NS_END