File indexing completed on 2024-04-21 03:59:21

 /*
     SPDX-FileCopyrightText: 2003 Lubos Lunak <l.lunak@kde.org>
 
     SPDX-License-Identifier: MIT
 */
 
 #include "kselectionwatcher.h"
 
 #include "kwindowsystem.h"
 #include <config-kwindowsystem.h>
 
 #include <QAbstractNativeEventFilter>
 #include <QCoreApplication>
 
 #include <private/qtx11extras_p.h>
 
 static xcb_window_t get_selection_owner(xcb_connection_t *c, xcb_atom_t selection)
 {
     xcb_window_t owner = XCB_NONE;
     xcb_get_selection_owner_reply_t *reply = xcb_get_selection_owner_reply(c, xcb_get_selection_owner(c, selection), nullptr);
 
     if (reply) {
         owner = reply->owner;
         free(reply);
     }
 
     return owner;
 }
 
 static xcb_atom_t intern_atom(xcb_connection_t *c, const char *name)
 {
     xcb_atom_t atom = XCB_NONE;
     xcb_intern_atom_reply_t *reply = xcb_intern_atom_reply(c, xcb_intern_atom(c, false, strlen(name), name), nullptr);
 
     if (reply) {
         atom = reply->atom;
         free(reply);
     }
 
     return atom;
 }
 
 //*******************************************
 // KSelectionWatcher
 //*******************************************
 
 class Q_DECL_HIDDEN KSelectionWatcher::Private : public QAbstractNativeEventFilter
 {
 public:
     Private(KSelectionWatcher *watcher_P, xcb_atom_t selection_P, xcb_connection_t *c, xcb_window_t root)
         : connection(c)
         , root(root)
         , selection(selection_P)
         , selection_owner(XCB_NONE)
         , watcher(watcher_P)
     {
         QCoreApplication::instance()->installNativeEventFilter(this);
     }
 
     xcb_connection_t *connection;
     xcb_window_t root;
     const xcb_atom_t selection;
     xcb_window_t selection_owner;
     static xcb_atom_t manager_atom;
 
     static Private *create(KSelectionWatcher *watcher, xcb_atom_t selection_P, int screen_P);
     static Private *create(KSelectionWatcher *watcher, const char *selection_P, int screen_P);
     static Private *create(KSelectionWatcher *watcher, xcb_atom_t selection_P, xcb_connection_t *c, xcb_window_t root);
     static Private *create(KSelectionWatcher *watcher, const char *selection_P, xcb_connection_t *c, xcb_window_t root);
 
 protected:
     bool nativeEventFilter(const QByteArray &eventType, void *message, qintptr *) override
     {
         if (eventType != "xcb_generic_event_t") {
             return false;
         }
         watcher->filterEvent(message);
         return false;
     }
 
 private:
     KSelectionWatcher *watcher;
 };
 
 KSelectionWatcher::Private *KSelectionWatcher::Private::create(KSelectionWatcher *watcher, xcb_atom_t selection_P, int screen_P)
 {
     if (KWindowSystem::isPlatformX11()) {
         return create(watcher, selection_P, QX11Info::connection(), QX11Info::appRootWindow(screen_P));
     }
     return nullptr;
 }
 
 KSelectionWatcher::Private *KSelectionWatcher::Private::create(KSelectionWatcher *watcher, xcb_atom_t selection_P, xcb_connection_t *c, xcb_window_t root)
 {
     return new Private(watcher, selection_P, c, root);
 }
 
 KSelectionWatcher::Private *KSelectionWatcher::Private::create(KSelectionWatcher *watcher, const char *selection_P, int screen_P)
 {
     if (KWindowSystem::isPlatformX11()) {
         return create(watcher, selection_P, QX11Info::connection(), QX11Info::appRootWindow(screen_P));
     }
     return nullptr;
 }
 
 KSelectionWatcher::Private *KSelectionWatcher::Private::create(KSelectionWatcher *watcher, const char *selection_P, xcb_connection_t *c, xcb_window_t root)
 {
     return new Private(watcher, intern_atom(c, selection_P), c, root);
 }
 
 KSelectionWatcher::KSelectionWatcher(xcb_atom_t selection_P, int screen_P, QObject *parent_P)
     : QObject(parent_P)
     , d(Private::create(this, selection_P, screen_P))
 {
     init();
 }
 
 KSelectionWatcher::KSelectionWatcher(const char *selection_P, int screen_P, QObject *parent_P)
     : QObject(parent_P)
     , d(Private::create(this, selection_P, screen_P))
 {
     init();
 }
 
 KSelectionWatcher::KSelectionWatcher(xcb_atom_t selection, xcb_connection_t *c, xcb_window_t root, QObject *parent)
     : QObject(parent)
     , d(Private::create(this, selection, c, root))
 {
     init();
 }
 
 KSelectionWatcher::KSelectionWatcher(const char *selection, xcb_connection_t *c, xcb_window_t root, QObject *parent)
     : QObject(parent)
     , d(Private::create(this, selection, c, root))
 {
     init();
 }
 
 KSelectionWatcher::~KSelectionWatcher()
 {
     delete d;
 }
 
 void KSelectionWatcher::init()
 {
     if (!d) {
         return;
     }
     if (Private::manager_atom == XCB_NONE) {
         xcb_connection_t *c = d->connection;
 
         xcb_intern_atom_cookie_t atom_cookie = xcb_intern_atom(c, false, strlen("MANAGER"), "MANAGER");
         xcb_get_window_attributes_cookie_t attr_cookie = xcb_get_window_attributes(c, d->root);
 
         xcb_intern_atom_reply_t *atom_reply = xcb_intern_atom_reply(c, atom_cookie, nullptr);
         Private::manager_atom = atom_reply->atom;
         free(atom_reply);
 
         xcb_get_window_attributes_reply_t *attr = xcb_get_window_attributes_reply(c, attr_cookie, nullptr);
         uint32_t event_mask = attr->your_event_mask;
         free(attr);
 
         if (!(event_mask & XCB_EVENT_MASK_STRUCTURE_NOTIFY)) {
             // We need XCB_EVENT_MASK_STRUCTURE_NORITY on the root window
             event_mask |= XCB_EVENT_MASK_STRUCTURE_NOTIFY;
             xcb_change_window_attributes(c, d->root, XCB_CW_EVENT_MASK, &event_mask);
         }
     }
 
     owner(); // trigger reading of current selection status
 }
 
 xcb_window_t KSelectionWatcher::owner()
 {
     if (!d) {
         return XCB_WINDOW_NONE;
     }
     xcb_connection_t *c = d->connection;
 
     xcb_window_t current_owner = get_selection_owner(c, d->selection);
     if (current_owner == XCB_NONE) {
         return XCB_NONE;
     }
 
     if (current_owner == d->selection_owner) {
         return d->selection_owner;
     }
 
     // We have a new selection owner - select for structure notify events
     uint32_t mask = XCB_EVENT_MASK_STRUCTURE_NOTIFY;
     xcb_void_cookie_t cookie = xcb_change_window_attributes_checked(c, current_owner, XCB_CW_EVENT_MASK, &mask);
 
     // Verify that the owner didn't change again while selecting for events
     xcb_window_t new_owner = get_selection_owner(c, d->selection);
     xcb_generic_error_t *err = xcb_request_check(c, cookie);
 
     if (!err && current_owner == new_owner) {
         d->selection_owner = current_owner;
         Q_EMIT newOwner(d->selection_owner);
     } else {
         // ### This doesn't look right - the selection could have an owner
         d->selection_owner = XCB_NONE;
     }
 
     if (err) {
         free(err);
     }
 
     return d->selection_owner;
 }
 
 void KSelectionWatcher::filterEvent(void *ev_P)
 {
     if (!d) {
         return;
     }
     xcb_generic_event_t *event = reinterpret_cast<xcb_generic_event_t *>(ev_P);
     const uint response_type = event->response_type & ~0x80;
     if (response_type == XCB_CLIENT_MESSAGE) {
         xcb_client_message_event_t *cm_event = reinterpret_cast<xcb_client_message_event_t *>(event);
 
         if (cm_event->type != Private::manager_atom || cm_event->data.data32[1] != d->selection) {
             return;
         }
         // owner() checks whether the owner changed and emits newOwner()
         owner();
         return;
     }
     if (response_type == XCB_DESTROY_NOTIFY) {
         xcb_destroy_notify_event_t *ev = reinterpret_cast<xcb_destroy_notify_event_t *>(event);
         if (d->selection_owner == XCB_NONE || ev->window != d->selection_owner) {
             return;
         }
 
         d->selection_owner = XCB_NONE; // in case the exactly same ID gets reused as the owner
 
         if (owner() == XCB_NONE) {
             Q_EMIT lostOwner(); // it must be safe to delete 'this' in a slot
         }
         return;
     }
 }
 
 xcb_atom_t KSelectionWatcher::Private::manager_atom = XCB_NONE;
 
 #include "moc_kselectionwatcher.cpp"