Port Client::transient_for handling to XCB

The type of the transient_for related variables are changed to
xcb_window_t. They cannot be Xcb::Window as we don't take ownership over
the transient for window.

Variables are renamed to m_camelCase to follow naming scheme.

A wrapper for retrieving the TransientFor hint is added to the Xcb
Wrappers.

client.cpp

@@ -99,8 +99,8 @@ Client::Client()
     , move_resize_has_keyboard_grab(false)
     , m_managed(false)
     , transient_for (NULL)
-    , transient_for_id(None)
+    , m_transientForId(XCB_WINDOW_NONE)
-    , original_transient_for_id(None)
+    , m_originalTransientForId(XCB_WINDOW_NONE)
     , shade_below(NULL)
     , skip_switcher(false)
     , blocks_compositing(false)

client.h

@@ -283,7 +283,7 @@ public:
     ClientList allMainClients() const; // Call once before loop , is indirect
     bool hasTransient(const Client* c, bool indirect) const;
     const ClientList& transients() const; // Is not indirect
-    void checkTransient(Window w);
+    void checkTransient(xcb_window_t w);
     Client* findModal(bool allow_itself = false);
     const Group* group() const;
     Group* group();
@@ -869,16 +869,16 @@ private:
     int quick_tile_mode;
 
     void readTransient();
-    Window verifyTransientFor(Window transient_for, bool set);
+    xcb_window_t verifyTransientFor(xcb_window_t transient_for, bool set);
     void addTransient(Client* cl);
     void removeTransient(Client* cl);
     void removeFromMainClients();
     void cleanGrouping();
     void checkGroupTransients();
-    void setTransient(Window new_transient_for_id);
+    void setTransient(xcb_window_t new_transient_for_id);
     Client* transient_for;
-    Window transient_for_id;
+    xcb_window_t m_transientForId;
-    Window original_transient_for_id;
+    xcb_window_t m_originalTransientForId;
     ClientList transients_list; // SELI TODO: Make this ordered in stacking order?
     ShadeMode shade_mode;
     Client *shade_below;
@@ -1033,19 +1033,19 @@ inline Client* Client::transientFor()
 
 inline bool Client::groupTransient() const
 {
-    return transient_for_id == rootWindow();
+    return m_transientForId == rootWindow();
 }
 
 // Needed because verifyTransientFor() may set transient_for_id to root window,
 // if the original value has a problem (window doesn't exist, etc.)
 inline bool Client::wasOriginallyGroupTransient() const
 {
-    return original_transient_for_id == rootWindow();
+    return m_originalTransientForId == rootWindow();
 }
 
 inline bool Client::isTransient() const
 {
-    return transient_for_id != None;
+    return m_transientForId != XCB_WINDOW_NONE;
 }
 
 inline const ClientList& Client::transients() const

group.cpp

@@ -588,26 +588,27 @@ bool Client::sameAppWindowRoleMatch(const Client* c1, const Client* c2, bool act
 void Client::readTransient()
 {
     TRANSIENCY_CHECK(this);
-    Window new_transient_for_id;
+    Xcb::TransientFor transientFor(window());
-    if (XGetTransientForHint(display(), window(), &new_transient_for_id)) {
+    xcb_window_t new_transient_for_id = XCB_WINDOW_NONE;
-        original_transient_for_id = new_transient_for_id;
+    if (transientFor.getTransientFor(&new_transient_for_id)) {
+        m_originalTransientForId = new_transient_for_id;
         new_transient_for_id = verifyTransientFor(new_transient_for_id, true);
     } else {
-        original_transient_for_id = None;
+        m_originalTransientForId = XCB_WINDOW_NONE;
-        new_transient_for_id = verifyTransientFor(None, false);
+        new_transient_for_id = verifyTransientFor(XCB_WINDOW_NONE, false);
     }
     setTransient(new_transient_for_id);
 }
 
-void Client::setTransient(Window new_transient_for_id)
+void Client::setTransient(xcb_window_t new_transient_for_id)
 {
     TRANSIENCY_CHECK(this);
-    if (new_transient_for_id != transient_for_id) {
+    if (new_transient_for_id != m_transientForId) {
         removeFromMainClients();
         transient_for = NULL;
-        transient_for_id = new_transient_for_id;
+        m_transientForId = new_transient_for_id;
-        if (transient_for_id != None && !groupTransient()) {
+        if (m_transientForId != XCB_WINDOW_NONE && !groupTransient()) {
-            transient_for = workspace()->findClient(WindowMatchPredicate(transient_for_id));
+            transient_for = workspace()->findClient(WindowMatchPredicate(m_transientForId));
             assert(transient_for != NULL);   // verifyTransient() had to check this
             transient_for->addTransient(this);
         } // checkGroup() will check 'check_active_modal'
@@ -755,18 +756,18 @@ void Client::checkGroupTransients()
 /*!
   Check that the window is not transient for itself, and similar nonsense.
  */
-Window Client::verifyTransientFor(Window new_transient_for, bool defined)
+xcb_window_t Client::verifyTransientFor(xcb_window_t new_transient_for, bool set)
 {
-    Window new_property_value = new_transient_for;
+    xcb_window_t new_property_value = new_transient_for;
     // make sure splashscreens are shown above all their app's windows, even though
     // they're in Normal layer
-    if (isSplash() && new_transient_for == None)
+    if (isSplash() && new_transient_for == XCB_WINDOW_NONE)
         new_transient_for = rootWindow();
-    if (new_transient_for == None) {
+    if (new_transient_for == XCB_WINDOW_NONE) {
-        if (defined)   // sometimes WM_TRANSIENT_FOR is set to None, instead of root window
+        if (set)   // sometimes WM_TRANSIENT_FOR is set to None, instead of root window
             new_property_value = new_transient_for = rootWindow();
         else
-            return None;
+            return XCB_WINDOW_NONE;
     }
     if (new_transient_for == window()) { // pointing to self
         // also fix the property itself
@@ -776,19 +777,15 @@ Window Client::verifyTransientFor(Window new_transient_for, bool defined)
 //  The transient_for window may be embedded in another application,
 //  so kwin cannot see it. Try to find the managed client for the
 //  window and fix the transient_for property if possible.
-    WId before_search = new_transient_for;
+    xcb_window_t before_search = new_transient_for;
-    while (new_transient_for != None
+    while (new_transient_for != XCB_WINDOW_NONE
             && new_transient_for != rootWindow()
             && !workspace()->findClient(WindowMatchPredicate(new_transient_for))) {
-        Window root_return, parent_return;
+        Xcb::Tree tree(new_transient_for);
-        Window* wins = NULL;
+        if (tree.isNull()) {
-        unsigned int nwins;
-        int r = XQueryTree(display(), new_transient_for, &root_return, &parent_return, &wins, &nwins);
-        if (wins)
-            XFree((void *) wins);
-        if (r == 0)
             break;
-        new_transient_for = parent_return;
+        }
+        new_transient_for = tree->parent;
     }
     if (Client* new_transient_for_client = workspace()->findClient(WindowMatchPredicate(new_transient_for))) {
         if (new_transient_for != before_search) {
@@ -802,12 +799,12 @@ Window Client::verifyTransientFor(Window new_transient_for, bool defined)
 // group transients cannot cause loops, because they're considered transient only for non-transient
 // windows in the group
     int count = 20;
-    Window loop_pos = new_transient_for;
+    xcb_window_t loop_pos = new_transient_for;
-    while (loop_pos != None && loop_pos != rootWindow()) {
+    while (loop_pos != XCB_WINDOW_NONE && loop_pos != rootWindow()) {
         Client* pos = workspace()->findClient(WindowMatchPredicate(loop_pos));
         if (pos == NULL)
             break;
-        loop_pos = pos->transient_for_id;
+        loop_pos = pos->m_transientForId;
         if (--count == 0 || pos == this) {
             kWarning(1216) << "Client " << this << " caused WM_TRANSIENT_FOR loop." ;
             new_transient_for = rootWindow();
@@ -818,8 +815,8 @@ Window Client::verifyTransientFor(Window new_transient_for, bool defined)
         // it's transient for a specific window, but that window is not mapped
         new_transient_for = rootWindow();
     }
-    if (new_property_value != original_transient_for_id)
+    if (new_property_value != m_originalTransientForId)
-        XSetTransientForHint(display(), window(), new_property_value);
+        xcb_icccm_set_wm_transient_for(connection(), window(), new_property_value);
     return new_transient_for;
 }
 
@@ -849,18 +846,18 @@ void Client::removeTransient(Client* cl)
     // cl is transient for this, but this is going away
     // make cl group transient
     if (cl->transientFor() == this) {
-        cl->transient_for_id = None;
+        cl->m_transientForId = XCB_WINDOW_NONE;
         cl->transient_for = NULL; // SELI
 // SELI       cl->setTransient( rootWindow());
-        cl->setTransient(None);
+        cl->setTransient(XCB_WINDOW_NONE);
     }
 }
 
 // A new window has been mapped. Check if it's not a mainwindow for this already existing window.
-void Client::checkTransient(Window w)
+void Client::checkTransient(xcb_window_t w)
 {
     TRANSIENCY_CHECK(this);
-    if (original_transient_for_id != w)
+    if (m_originalTransientForId != w)
         return;
     w = verifyTransientFor(w, true);
     setTransient(w);

xcbutils.h

@@ -29,6 +29,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 #include <xcb/xcb.h>
 #include <xcb/composite.h>
+#include <xcb/xcb_icccm.h>
 
 namespace KWin {
 
@@ -206,6 +207,27 @@ public:
     }
 };
 
+class TransientFor : public Wrapper<xcb_get_property_reply_t, xcb_get_property_cookie_t, &xcb_get_property_reply, &xcb_icccm_get_wm_transient_for_unchecked>
+{
+public:
+    explicit TransientFor(WindowId window) : Wrapper<xcb_get_property_reply_t, xcb_get_property_cookie_t, &xcb_get_property_reply, &xcb_icccm_get_wm_transient_for_unchecked>(window) {}
+
+    /**
+     * @brief Fill given window pointer with the WM_TRANSIENT_FOR property of a window.
+     * @param prop WM_TRANSIENT_FOR property value.
+     * @returns @c true on success, @c false otherwise
+     **/
+    inline bool getTransientFor(WindowId *prop) {
+        if (isNull()) {
+            return false;
+        }
+        if (xcb_icccm_get_wm_transient_for_from_reply(prop, const_cast<xcb_get_property_reply_t*>(data()))) {
+            return true;
+        }
+        return false;
+    }
+};
+
 class ExtensionData
 {
 public: