ui/gtk: add clipboard support

This patch adds clipboard support to the qemu gtk ui.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-id: 20210519053940.1888907-1-kraxel@redhat.com
Message-Id: <20210519053940.1888907-10-kraxel@redhat.com>

3 files changed, 194 insertions, 1 deletions

diff --git a/ui/gtk-clipboard.c b/ui/gtk-clipboard.c
new file mode 100644
index 0000000000..bff28d2030
--- /dev/null
+++ b/ui/gtk-clipboard.c
@@ -0,0 +1,192 @@
+/*
+ * GTK UI -- clipboard support
+ *
+ * Copyright (C) 2021 Gerd Hoffmann <kraxel@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include "qemu/osdep.h"
+#include "qemu-common.h"
+#include "qemu/main-loop.h"
+
+#include "ui/gtk.h"
+
+static QemuClipboardSelection gd_find_selection(GtkDisplayState *gd,
+                                                GtkClipboard *clipboard)
+{
+    QemuClipboardSelection s;
+
+    for (s = 0; s < QEMU_CLIPBOARD_SELECTION__COUNT; s++) {
+        if (gd->gtkcb[s] == clipboard) {
+            return s;
+        }
+    }
+    return QEMU_CLIPBOARD_SELECTION_CLIPBOARD;
+}
+
+static void gd_clipboard_get_data(GtkClipboard     *clipboard,
+                                  GtkSelectionData *selection_data,
+                                  guint             selection_info,
+                                  gpointer          data)
+{
+    GtkDisplayState *gd = data;
+    QemuClipboardSelection s = gd_find_selection(gd, clipboard);
+    QemuClipboardType type = QEMU_CLIPBOARD_TYPE_TEXT;
+    QemuClipboardInfo *info = qemu_clipboard_info_ref(gd->cbinfo[s]);
+
+    qemu_clipboard_request(info, type);
+    while (info == gd->cbinfo[s] &&
+           info->types[type].available &&
+           info->types[type].data == NULL) {
+        main_loop_wait(false);
+    }
+
+    if (info == gd->cbinfo[s] && gd->cbowner[s]) {
+        gtk_selection_data_set_text(selection_data,
+                                    info->types[type].data,
+                                    info->types[type].size);
+    } else {
+        /* clipboard owner changed while waiting for the data */
+    }
+
+    qemu_clipboard_info_unref(info);
+}
+
+static void gd_clipboard_clear(GtkClipboard *clipboard,
+                               gpointer data)
+{
+    GtkDisplayState *gd = data;
+    QemuClipboardSelection s = gd_find_selection(gd, clipboard);
+
+    gd->cbowner[s] = false;
+}
+
+static void gd_clipboard_notify(Notifier *notifier, void *data)
+{
+    GtkDisplayState *gd = container_of(notifier, GtkDisplayState, cbpeer.update);
+    QemuClipboardInfo *info = data;
+    QemuClipboardSelection s = info->selection;
+    bool self_update = info->owner == &gd->cbpeer;
+
+    if (info != gd->cbinfo[s]) {
+        qemu_clipboard_info_unref(gd->cbinfo[s]);
+        gd->cbinfo[s] = qemu_clipboard_info_ref(info);
+        gd->cbpending[s] = 0;
+        if (!self_update) {
+            GtkTargetList *list;
+            GtkTargetEntry *targets;
+            gint n_targets;
+
+            list = gtk_target_list_new(NULL, 0);
+            if (info->types[QEMU_CLIPBOARD_TYPE_TEXT].available) {
+                gtk_target_list_add_text_targets(list, 0);
+            }
+            targets = gtk_target_table_new_from_list(list, &n_targets);
+
+            gtk_clipboard_clear(gd->gtkcb[s]);
+            gd->cbowner[s] = true;
+            gtk_clipboard_set_with_data(gd->gtkcb[s],
+                                        targets, n_targets,
+                                        gd_clipboard_get_data,
+                                        gd_clipboard_clear,
+                                        gd);
+
+            gtk_target_table_free(targets, n_targets);
+            gtk_target_list_unref(list);
+        }
+        return;
+    }
+
+    if (self_update) {
+        return;
+    }
+
+    /*
+     * Clipboard got updated, with data probably.  No action here, we
+     * are waiting for updates in gd_clipboard_get_data().
+     */
+}
+
+static void gd_clipboard_request(QemuClipboardInfo *info,
+                                 QemuClipboardType type)
+{
+    GtkDisplayState *gd = container_of(info->owner, GtkDisplayState, cbpeer);
+    char *text;
+
+    switch (type) {
+    case QEMU_CLIPBOARD_TYPE_TEXT:
+        text = gtk_clipboard_wait_for_text(gd->gtkcb[info->selection]);
+        if (text) {
+            qemu_clipboard_set_data(&gd->cbpeer, info, type,
+                                    strlen(text), text, true);
+            g_free(text);
+        }
+        break;
+    default:
+        break;
+    }
+}
+
+static void gd_owner_change(GtkClipboard *clipboard,
+                            GdkEvent *event,
+                            gpointer data)
+{
+    GtkDisplayState *gd = data;
+    QemuClipboardSelection s = gd_find_selection(gd, clipboard);
+    QemuClipboardInfo *info;
+
+    if (gd->cbowner[s]) {
+        /* ignore notifications about our own grabs */
+        return;
+    }
+
+
+    switch (event->owner_change.reason) {
+    case GDK_SETTING_ACTION_NEW:
+        info = qemu_clipboard_info_new(&gd->cbpeer, s);
+        if (gtk_clipboard_wait_is_text_available(clipboard)) {
+            info->types[QEMU_CLIPBOARD_TYPE_TEXT].available = true;
+        }
+
+        qemu_clipboard_update(info);
+        qemu_clipboard_info_unref(info);
+        break;
+    default:
+        break;
+    }
+}
+
+void gd_clipboard_init(GtkDisplayState *gd)
+{
+    gd->cbpeer.name = "gtk";
+    gd->cbpeer.update.notify = gd_clipboard_notify;
+    gd->cbpeer.request = gd_clipboard_request;
+    qemu_clipboard_peer_register(&gd->cbpeer);
+
+    gd->gtkcb[QEMU_CLIPBOARD_SELECTION_CLIPBOARD] =
+        gtk_clipboard_get(gdk_atom_intern("CLIPBOARD", FALSE));
+    gd->gtkcb[QEMU_CLIPBOARD_SELECTION_PRIMARY] =
+        gtk_clipboard_get(gdk_atom_intern("PRIMARY", FALSE));
+    gd->gtkcb[QEMU_CLIPBOARD_SELECTION_SECONDARY] =
+        gtk_clipboard_get(gdk_atom_intern("SECONDARY", FALSE));
+
+    g_signal_connect(gd->gtkcb[QEMU_CLIPBOARD_SELECTION_CLIPBOARD],
+                     "owner-change", G_CALLBACK(gd_owner_change), gd);
+    g_signal_connect(gd->gtkcb[QEMU_CLIPBOARD_SELECTION_PRIMARY],
+                     "owner-change", G_CALLBACK(gd_owner_change), gd);
+    g_signal_connect(gd->gtkcb[QEMU_CLIPBOARD_SELECTION_SECONDARY],
+                     "owner-change", G_CALLBACK(gd_owner_change), gd);
+}
diff --git a/ui/gtk.c b/ui/gtk.c
index 7da288a251..98046f577b 100644
--- a/ui/gtk.c
+++ b/ui/gtk.c
@@ -2267,6 +2267,7 @@ static void gtk_display_init(DisplayState *ds, DisplayOptions *opts)
         opts->u.gtk.grab_on_hover) {
         gtk_menu_item_activate(GTK_MENU_ITEM(s->grab_on_hover_item));
     }
+    gd_clipboard_init(s);
 }
 
 static void early_gtk_display_init(DisplayOptions *opts)
diff --git a/ui/meson.build b/ui/meson.build
index f37ef882e0..b5aed14886 100644
--- a/ui/meson.build
+++ b/ui/meson.build
@@ -65,7 +65,7 @@ if gtk.found()
   softmmu_ss.add(when: 'CONFIG_WIN32', if_true: files('win32-kbd-hook.c'))
 
   gtk_ss = ss.source_set()
-  gtk_ss.add(gtk, vte, pixman, files('gtk.c'))
+  gtk_ss.add(gtk, vte, pixman, files('gtk.c', 'gtk-clipboard.c'))
   gtk_ss.add(when: x11, if_true: files('x_keymap.c'))
   gtk_ss.add(when: [opengl, 'CONFIG_OPENGL'], if_true: files('gtk-gl-area.c'))
   gtk_ss.add(when: [x11, opengl, 'CONFIG_OPENGL'], if_true: files('gtk-egl.c'))