Allow dropping more data types on PGTK

* lisp/loadup.el (featurep): Load `pgtk-dnd'.
* lisp/pgtk-dnd.el: New file.
(pgtk-dnd-test-function, pgtk-dnd-types-alist)
(pgtk-dnd-known-types, pgtk-dnd-use-offix-drop)
(pgtk-dnd-current-state, pgtk-get-selection-internal)
(pgtk-register-dnd-targets, pgtk-dnd-empty-state)
(pgtk-dnd-init-frame, pgtk-dnd-get-state-cons-for-frame)
(pgtk-dnd-get-state-for-frame, pgtk-dnd-default-test-function)
(pgtk-dnd-current-type, pgtk-dnd-forget-drop)
(pgtk-dnd-maybe-call-test-function, pgtk-dnd-save-state)
(pgtk-dnd-handle-moz-url, pgtk-dnd-insert-utf8-text)
(pgtk-dnd-insert-utf16-text, pgtk-dnd-insert-ctext)
(pgtk-dnd-handle-uri-list, pgtk-dnd-handle-file-name)
(pgtk-dnd-choose-type, pgtk-dnd-drop-data)
(pgtk-dnd-handle-drag-n-drop-event, pgtk-update-drop-status)
(pgtk-drop-finish, pgtk-dnd-handle-gdk, pgtk-dnd): New variables
and functions and library.

* lisp/term/pgtk-win.el (special-event-map): Load
`drag-n-drop-event'.
(after-make-frame-functions): Register DND after make frame
functions.

* src/emacs.c (main): Stop calling empty init_pgtkterm function.

* src/pgtkselect.c (Fpgtk_register_dnd_targets, Fpgtk_drop_finish)
(Fpgtk_update_drop_status): New functions.
(syms_of_pgtkselect): Register new functions.
* src/pgtkterm.c (struct event_queue_t): Fix coding style of
definition.
(symbol_to_drag_action, drag_action_to_symbol)
(pgtk_update_drop_status, pgtk_finish_drop): New functions.
(drag_data_received): Delete function.
(pgtk_set_event_handler): Register for DND correctly.
(syms_of_pgtkterm): New defsyms for DND types.
(init_pgtkterm): Delete function.

* src/pgtkterm.h: Update prototypes, fix prototype coding style.

4 files changed, 378 insertions, 120 deletions

diff --git a/src/emacs.c b/src/emacs.c
index 37c6c76e7a3..3c768412818 100644
--- a/src/emacs.c
+++ b/src/emacs.c
@@ -1930,9 +1930,6 @@ Using an Emacs configured with --with-x-toolkit=lucid does not have this problem
   init_bignum ();
   init_threads ();
   init_eval ();
-#ifdef HAVE_PGTK
-  init_pgtkterm (); /* Must come before `init_atimer'.  */
-#endif
   running_asynch_code = 0;
   init_random ();
   init_xfaces ();
diff --git a/src/pgtkselect.c b/src/pgtkselect.c
index 122b5d8c073..2a4f6adba4b 100644
--- a/src/pgtkselect.c
+++ b/src/pgtkselect.c
@@ -1762,6 +1762,86 @@ pgtk_handle_selection_notify (GdkEventSelection *event)
            (event->property != GDK_NONE ? Qt : Qlambda));
 }
 
+
+/***********************************************************************
+                      Drag and drop support
+***********************************************************************/
+
+DEFUN ("pgtk-register-dnd-targets", Fpgtk_register_dnd_targets,
+       Spgtk_register_dnd_targets, 2, 2, 0,
+       doc: /* Register TARGETS on FRAME.
+TARGETS should be a list of strings describing data types (selection
+targets) that can be dropped on top of FRAME.  */)
+  (Lisp_Object frame, Lisp_Object targets)
+{
+  struct frame *f;
+  GtkTargetEntry *entries;
+  GtkTargetList *list;
+  ptrdiff_t length, n;
+  Lisp_Object tem, t;
+  char *buf;
+  USE_SAFE_ALLOCA;
+
+  f = decode_window_system_frame (frame);
+  CHECK_LIST (targets);
+  length = list_length (targets);
+  n = 0;
+  entries = SAFE_ALLOCA (sizeof *entries * length);
+  memset (entries, 0, sizeof *entries * length);
+  tem = targets;
+
+  FOR_EACH_TAIL (tem)
+    {
+      if (!CONSP (tem))
+        continue;
+
+      t = XCAR (tem);
+
+      CHECK_STRING (t);
+      SAFE_ALLOCA_STRING (buf, t);
+
+      entries[n++].target = buf;
+    }
+  CHECK_LIST_END (tem, targets);
+
+  if (n != length)
+    emacs_abort ();
+
+  list = gtk_target_list_new (entries, n);
+  gtk_drag_dest_set_target_list (FRAME_GTK_WIDGET (f), list);
+  gtk_target_list_unref (list);
+
+  SAFE_FREE ();
+
+  return Qnil;
+}
+
+DEFUN ("pgtk-drop-finish", Fpgtk_drop_finish, Spgtk_drop_finish, 3, 3, 0,
+       doc: /* Finish the drag-n-drop event that happened at TIMESTAMP.
+SUCCESS is whether or not the drop was successful, i.e. the action
+chosen in the last call to `pgtk-update-drop-status' was performed.
+TIMESTAMP is the time associated with the drag-n-drop event that is
+being finished.
+DELETE is whether or not the action was `move'.  */)
+  (Lisp_Object success, Lisp_Object timestamp, Lisp_Object delete)
+{
+  pgtk_finish_drop (success, timestamp, delete);
+
+  return Qnil;
+}
+
+DEFUN ("pgtk-update-drop-status", Fpgtk_update_drop_status,
+       Spgtk_update_drop_status, 2, 2, 0,
+       doc: /* Update the status of the current drag-and-drop operation.
+ACTION is the action the drop source should take.
+TIMESTAMP is the same as in `pgtk-drop-finish'.  */)
+  (Lisp_Object action, Lisp_Object timestamp)
+{
+  pgtk_update_drop_status (action, timestamp);
+
+  return Qnil;
+}
+
 void
 syms_of_pgtkselect (void)
 {
@@ -1777,23 +1857,22 @@ syms_of_pgtkselect (void)
   DEFSYM (QNULL, "NULL");
   DEFSYM (QATOM, "ATOM");
   DEFSYM (QTARGETS, "TARGETS");
-
-  DEFSYM (Qpgtk_sent_selection_functions,
-          "pgtk-sent-selection-functions");
-  DEFSYM (Qpgtk_lost_selection_functions,
-          "pgtk-lost-selection-functions");
-
-  DEFSYM (Qforeign_selection, "foreign-selection");
   DEFSYM (QUTF8_STRING, "UTF8_STRING");
-  DEFSYM (QSTRING, "STRING");
   DEFSYM (QCOMPOUND_TEXT, "COMPOUND_TEXT");
-  DEFSYM (Qtext_plain_charset_utf_8, "text/plain;charset=utf-8");
+
+  DEFSYM (Qforeign_selection, "foreign-selection");
+
+  DEFSYM (Qpgtk_sent_selection_functions, "pgtk-sent-selection-functions");
+  DEFSYM (Qpgtk_lost_selection_functions, "pgtk-lost-selection-functions");
 
   defsubr (&Spgtk_disown_selection_internal);
   defsubr (&Spgtk_get_selection_internal);
   defsubr (&Spgtk_own_selection_internal);
   defsubr (&Spgtk_selection_exists_p);
   defsubr (&Spgtk_selection_owner_p);
+  defsubr (&Spgtk_register_dnd_targets);
+  defsubr (&Spgtk_update_drop_status);
+  defsubr (&Spgtk_drop_finish);
 
   DEFVAR_LISP ("selection-converter-alist", Vselection_converter_alist,
                doc: /* SKIP: real doc in xselect.c.  */);
@@ -1817,7 +1896,7 @@ The functions are called with three arguments:
 We might have failed (and declined the request) for any number of reasons,
 including being asked for a selection that we no longer own, or being asked
 to convert into a type that we don't know about or that is inappropriate.
-This hook doesn't let you change the behavior of Emacs's selection replies,
+xThis hook doesn't let you change the behavior of Emacs's selection replies,
 it merely informs you that they have happened.  */);
   Vpgtk_sent_selection_functions = Qnil;
 
diff --git a/src/pgtkterm.c b/src/pgtkterm.c
index 91874ff58a5..a123311366a 100644
--- a/src/pgtkterm.c
+++ b/src/pgtkterm.c
@@ -76,25 +76,36 @@ along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */
 
 static bool any_help_event_p;
 
-struct pgtk_display_info *x_display_list;       /* Chain of existing displays */
-extern Lisp_Object tip_frame;
+/* Chain of existing displays */
+struct pgtk_display_info *x_display_list;
 
-static struct event_queue_t
+struct event_queue_t
 {
   union buffered_input_event *q;
   int nr, cap;
-} event_q = {
-  NULL, 0, 0,
 };
 
+/* A queue of events that will be read by the read_socket_hook.  */
+static struct event_queue_t event_q;
+
 /* Non-zero timeout value means ignore next mouse click if it arrives
    before that timeout elapses (i.e. as part of the same sequence of
    events resulting from clicking on a frame to select it).  */
-
 static Time ignore_next_mouse_click_timeout;
 
+/* The default Emacs icon .  */
 static Lisp_Object xg_default_icon_file;
 
+/* The current GdkDragContext of a drop.  */
+static GdkDragContext *current_drop_context;
+
+/* Whether or not current_drop_context was set from a drop
+   handler.  */
+static bool current_drop_context_drop;
+
+/* The time of the last drop.  */
+static guint32 current_drop_time;
+
 static void pgtk_delete_display (struct pgtk_display_info *);
 static void pgtk_clear_frame_area (struct frame *, int, int, int, int);
 static void pgtk_fill_rectangle (struct frame *, unsigned long, int, int,
@@ -6146,40 +6157,217 @@ scroll_event (GtkWidget *widget, GdkEvent *event, gpointer *user_data)
   return TRUE;
 }
 
+
+
+/* C part of drop handling code.
+   The Lisp part is in pgtk-dnd.el.  */
+
+static GdkDragAction
+symbol_to_drag_action (Lisp_Object act)
+{
+  if (EQ (act, Qcopy))
+    return GDK_ACTION_COPY;
+
+  if (EQ (act, Qmove))
+    return GDK_ACTION_MOVE;
+
+  if (EQ (act, Qlink))
+    return GDK_ACTION_LINK;
+
+  if (EQ (act, Qprivate))
+    return GDK_ACTION_PRIVATE;
+
+  if (NILP (act))
+    return GDK_ACTION_DEFAULT;
+
+  signal_error ("Invalid drag acction", act);
+}
+
+static Lisp_Object
+drag_action_to_symbol (GdkDragAction action)
+{
+  switch (action)
+    {
+    case GDK_ACTION_COPY:
+      return Qcopy;
+
+    case GDK_ACTION_MOVE:
+      return Qmove;
+
+    case GDK_ACTION_LINK:
+      return Qlink;
+
+    case GDK_ACTION_PRIVATE:
+      return Qprivate;
+
+    case GDK_ACTION_DEFAULT:
+    default:
+      return Qnil;
+    }
+}
+
+void
+pgtk_update_drop_status (Lisp_Object action, Lisp_Object event_time)
+{
+  guint32 time;
+
+  CONS_TO_INTEGER (event_time, guint32, time);
+
+  if (!current_drop_context || time < current_drop_time)
+    return;
+
+  gdk_drag_status (current_drop_context,
+                   symbol_to_drag_action (action),
+                   time);
+}
+
+void
+pgtk_finish_drop (Lisp_Object success, Lisp_Object event_time,
+                  Lisp_Object del)
+{
+  guint32 time;
+
+  CONS_TO_INTEGER (event_time, guint32, time);
+
+  if (!current_drop_context || time < current_drop_time)
+    return;
+
+  gtk_drag_finish (current_drop_context, !NILP (success),
+                   !NILP (del), time);
+
+  if (current_drop_context_drop)
+    g_clear_pointer (&current_drop_context,
+                     g_object_unref);
+}
+
 static void
-drag_data_received (GtkWidget *widget, GdkDragContext *context,
-                    gint x, gint y, GtkSelectionData *data,
-                    guint info, guint time, gpointer user_data)
+drag_leave (GtkWidget *widget, GdkDragContext *context,
+            guint time, gpointer user_data)
 {
-  struct frame *f = pgtk_any_window_to_frame (gtk_widget_get_window (widget));
-  gchar **uris = gtk_selection_data_get_uris (data);
+  struct frame *f;
+  union buffered_input_event inev;
+
+  f = pgtk_any_window_to_frame (gtk_widget_get_window (widget));
 
-  if (uris != NULL)
+  if (current_drop_context)
     {
-      for (int i = 0; uris[i] != NULL; i++)
-        {
-          union buffered_input_event inev;
-          Lisp_Object arg = Qnil;
+      if (current_drop_context_drop)
+        gtk_drag_finish (current_drop_context,
+                         FALSE, FALSE, current_drop_time);
 
-          EVENT_INIT (inev.ie);
-          inev.ie.kind = NO_EVENT;
-          inev.ie.arg = Qnil;
+      g_clear_pointer (&current_drop_context,
+                       g_object_unref);
+    }
 
-          arg = list2 (Qurl, build_string (uris[i]));
+  inev.ie.kind = DRAG_N_DROP_EVENT;
+  inev.ie.modifiers = 0;
+  inev.ie.arg = Qnil;
+  inev.ie.timestamp = time;
 
-          inev.ie.kind = DRAG_N_DROP_EVENT;
-          inev.ie.modifiers = 0;
-          XSETINT (inev.ie.x, x);
-          XSETINT (inev.ie.y, y);
-          XSETFRAME (inev.ie.frame_or_window, f);
-          inev.ie.arg = arg;
-          inev.ie.timestamp = 0;
+  XSETINT (inev.ie.x, 0);
+  XSETINT (inev.ie.y, 0);
+  XSETFRAME (inev.ie.frame_or_window, f);
 
-          evq_enqueue (&inev);
-        }
+  evq_enqueue (&inev);
+}
+
+static gboolean
+drag_motion (GtkWidget *widget, GdkDragContext *context,
+             gint x, gint y, guint time)
+
+{
+  struct frame *f;
+  union buffered_input_event inev;
+  GdkAtom name;
+  GdkDragAction suggestion;
+
+  f = pgtk_any_window_to_frame (gtk_widget_get_window (widget));
+
+  if (!f)
+    return FALSE;
+
+  if (current_drop_context)
+    {
+      if (current_drop_context_drop)
+        gtk_drag_finish (current_drop_context,
+                         FALSE, FALSE, current_drop_time);
+
+      g_clear_pointer (&current_drop_context,
+                       g_object_unref);
     }
 
-  gtk_drag_finish (context, TRUE, FALSE, time);
+  current_drop_context = g_object_ref (context);
+  current_drop_time = time;
+  current_drop_context_drop = false;
+
+  name = gdk_drag_get_selection (context);
+  suggestion = gdk_drag_context_get_suggested_action (context);
+
+  EVENT_INIT (inev.ie);
+
+  inev.ie.kind = DRAG_N_DROP_EVENT;
+  inev.ie.modifiers = 0;
+  inev.ie.arg = list4 (Qlambda, intern (gdk_atom_name (name)),
+                       make_uint (time),
+                       drag_action_to_symbol (suggestion));
+  inev.ie.timestamp = time;
+
+  XSETINT (inev.ie.x, x);
+  XSETINT (inev.ie.y, y);
+  XSETFRAME (inev.ie.frame_or_window, f);
+
+  evq_enqueue (&inev);
+
+  return TRUE;
+}
+
+static gboolean
+drag_drop (GtkWidget *widget, GdkDragContext *context,
+           int x, int y, guint time, gpointer user_data)
+{
+  struct frame *f;
+  union buffered_input_event inev;
+  GdkAtom name;
+  GdkDragAction selected_action;
+
+  f = pgtk_any_window_to_frame (gtk_widget_get_window (widget));
+
+  if (!f)
+    return FALSE;
+
+  if (current_drop_context)
+    {
+      if (current_drop_context_drop)
+        gtk_drag_finish (current_drop_context,
+                         FALSE, FALSE, current_drop_time);
+
+      g_clear_pointer (&current_drop_context,
+                       g_object_unref);
+    }
+
+  current_drop_context = g_object_ref (context);
+  current_drop_time = time;
+  current_drop_context_drop = true;
+
+  name = gdk_drag_get_selection (context);
+  selected_action = gdk_drag_context_get_selected_action (context);
+
+  EVENT_INIT (inev.ie);
+
+  inev.ie.kind = DRAG_N_DROP_EVENT;
+  inev.ie.modifiers = 0;
+  inev.ie.arg = list4 (Qquote, intern (gdk_atom_name (name)),
+                       make_uint (time),
+                       drag_action_to_symbol (selected_action));
+  inev.ie.timestamp = time;
+
+  XSETINT (inev.ie.x, x);
+  XSETINT (inev.ie.y, y);
+  XSETFRAME (inev.ie.frame_or_window, f);
+
+  evq_enqueue (&inev);
+
+  return TRUE;
 }
 
 static void
@@ -6208,9 +6396,9 @@ pgtk_set_event_handler (struct frame *f)
       return;
     }
 
-  gtk_drag_dest_set (FRAME_GTK_WIDGET (f), GTK_DEST_DEFAULT_ALL, NULL, 0,
-                     GDK_ACTION_COPY);
-  gtk_drag_dest_add_uri_targets (FRAME_GTK_WIDGET (f));
+  gtk_drag_dest_set (FRAME_GTK_WIDGET (f), 0, NULL, 0,
+                     (GDK_ACTION_MOVE | GDK_ACTION_COPY
+                      | GDK_ACTION_LINK | GDK_ACTION_PRIVATE));
 
   if (FRAME_GTK_OUTER_WIDGET (f))
     {
@@ -6251,8 +6439,12 @@ pgtk_set_event_handler (struct frame *f)
                     G_CALLBACK (scroll_event), NULL);
   g_signal_connect (G_OBJECT (FRAME_GTK_WIDGET (f)), "configure-event",
                     G_CALLBACK (configure_event), NULL);
-  g_signal_connect (G_OBJECT (FRAME_GTK_WIDGET (f)), "drag-data-received",
-                    G_CALLBACK (drag_data_received), NULL);
+  g_signal_connect (G_OBJECT (FRAME_GTK_WIDGET (f)), "drag-leave",
+                    G_CALLBACK (drag_leave), NULL);
+  g_signal_connect (G_OBJECT (FRAME_GTK_WIDGET (f)), "drag-motion",
+                    G_CALLBACK (drag_motion), NULL);
+  g_signal_connect (G_OBJECT (FRAME_GTK_WIDGET (f)), "drag-drop",
+                    G_CALLBACK (drag_drop), NULL);
   g_signal_connect (G_OBJECT (FRAME_GTK_WIDGET (f)), "draw",
                     G_CALLBACK (pgtk_handle_draw), NULL);
   g_signal_connect (G_OBJECT (FRAME_GTK_WIDGET (f)), "property-notify-event",
@@ -6803,12 +6995,17 @@ syms_of_pgtkterm (void)
 
   DEFSYM (Qlatin_1, "latin-1");
 
-  xg_default_icon_file =
-    build_pure_c_string ("icons/hicolor/scalable/apps/emacs.svg");
+  xg_default_icon_file
+    = build_pure_c_string ("icons/hicolor/scalable/apps/emacs.svg");
   staticpro (&xg_default_icon_file);
 
   DEFSYM (Qx_gtk_map_stock, "x-gtk-map-stock");
 
+  DEFSYM (Qcopy, "copy");
+  DEFSYM (Qmove, "move");
+  DEFSYM (Qlink, "link");
+  DEFSYM (Qprivate, "private");
+
 
   Fput (Qalt, Qmodifier_value, make_fixnum (alt_modifier));
   Fput (Qhyper, Qmodifier_value, make_fixnum (hyper_modifier));
@@ -7093,8 +7290,3 @@ pgtk_cr_export_frames (Lisp_Object frames, cairo_surface_type_t surface_type)
 
   return CALLN (Fapply, intern ("concat"), Fnreverse (acc));
 }
-
-void
-init_pgtkterm (void)
-{
-}
diff --git a/src/pgtkterm.h b/src/pgtkterm.h
index 86578be6b56..fcc6c5310e9 100644
--- a/src/pgtkterm.h
+++ b/src/pgtkterm.h
@@ -448,9 +448,9 @@ enum
 #define FRAME_FONT(f)             (FRAME_X_OUTPUT (f)->font)
 #define FRAME_GTK_OUTER_WIDGET(f) (FRAME_X_OUTPUT (f)->widget)
 #define FRAME_GTK_WIDGET(f)       (FRAME_X_OUTPUT (f)->edit_widget)
-#define FRAME_WIDGET(f)           (FRAME_GTK_OUTER_WIDGET (f) ?         \
-                                   FRAME_GTK_OUTER_WIDGET (f) :         \
-                                   FRAME_GTK_WIDGET (f))
+#define FRAME_WIDGET(f)           (FRAME_GTK_OUTER_WIDGET (f)   \
+                                   ? FRAME_GTK_OUTER_WIDGET (f) \
+                                   : FRAME_GTK_WIDGET (f))
 
 #define FRAME_PGTK_VIEW(f)         FRAME_GTK_WIDGET (f)
 #define FRAME_X_WINDOW(f)          FRAME_GTK_OUTER_WIDGET (f)
@@ -538,69 +538,57 @@ extern void pgtk_handle_property_notify (GdkEventProperty *);
 extern void pgtk_handle_selection_notify (GdkEventSelection *);
 
 /* Display init/shutdown functions implemented in pgtkterm.c */
-extern struct pgtk_display_info *pgtk_term_init (Lisp_Object display_name,
-                                                 char *resource_name);
-extern void pgtk_term_shutdown (int sig);
+extern struct pgtk_display_info *pgtk_term_init (Lisp_Object, char *);
+extern void pgtk_term_shutdown (int);
 
 /* Implemented in pgtkterm, published in or needed from pgtkfns. */
-extern void pgtk_clear_frame (struct frame *f);
-extern char *pgtk_xlfd_to_fontname (const char *xlfd);
+extern void pgtk_clear_frame (struct frame *);
+extern char *pgtk_xlfd_to_fontname (const char *);
 
 /* Implemented in pgtkfns.c.  */
 extern void pgtk_set_doc_edited (void);
-extern const char *pgtk_get_defaults_value (const char *key);
-extern const char *pgtk_get_string_resource (XrmDatabase rdb,
-                                             const char *name,
-                                             const char *class);
-extern void pgtk_implicitly_set_name (struct frame *f, Lisp_Object arg,
-                                      Lisp_Object oldval);
+extern const char *pgtk_get_defaults_value (const char *);
+extern const char *pgtk_get_string_resource (XrmDatabase, const char *, const char *);
+extern void pgtk_implicitly_set_name (struct frame *, Lisp_Object, Lisp_Object);
 
 /* Color management implemented in pgtkterm. */
-extern bool pgtk_defined_color (struct frame *f,
-                                const char *name,
-                                Emacs_Color * color_def, bool alloc,
-                                bool makeIndex);
-extern void pgtk_query_color (struct frame *f, Emacs_Color * color);
-extern void pgtk_query_colors (struct frame *f, Emacs_Color * colors,
-                               int ncolors);
-extern int pgtk_parse_color (struct frame *f, const char *color_name,
-                             Emacs_Color * color);
+extern bool pgtk_defined_color (struct frame *, const char *,
+                                Emacs_Color *, bool, bool);
+extern void pgtk_query_color (struct frame *, Emacs_Color *);
+extern void pgtk_query_colors (struct frame *, Emacs_Color *, int);
+extern int pgtk_parse_color (struct frame *, const char *, Emacs_Color *);
 
 /* Implemented in pgtkterm.c */
-extern void pgtk_clear_area (struct frame *f, int x, int y, int width,
-                             int height);
-extern int pgtk_gtk_to_emacs_modifiers (struct pgtk_display_info *dpyinfo,
-                                        int state);
-extern void pgtk_clear_under_internal_border (struct frame *f);
-extern void pgtk_set_event_handler (struct frame *f);
+extern void pgtk_clear_area (struct frame *, int, int, int, int);
+extern int pgtk_gtk_to_emacs_modifiers (struct pgtk_display_info *, int);
+extern void pgtk_clear_under_internal_border (struct frame *);
+extern void pgtk_set_event_handler (struct frame *);
 
 /* Implemented in pgtkterm.c */
 extern int pgtk_display_pixel_height (struct pgtk_display_info *);
 extern int pgtk_display_pixel_width (struct pgtk_display_info *);
 
-extern void pgtk_destroy_window (struct frame *f);
-extern void pgtk_set_parent_frame (struct frame *f, Lisp_Object, Lisp_Object);
+extern void pgtk_destroy_window (struct frame *);
+extern void pgtk_set_parent_frame (struct frame *, Lisp_Object, Lisp_Object);
 extern void pgtk_set_no_focus_on_map (struct frame *, Lisp_Object, Lisp_Object);
 extern void pgtk_set_no_accept_focus (struct frame *, Lisp_Object, Lisp_Object);
 extern void pgtk_set_z_group (struct frame *, Lisp_Object, Lisp_Object);
 
 /* Cairo related functions implemented in pgtkterm.c */
 extern void pgtk_cr_update_surface_desired_size (struct frame *, int, int, bool);
-extern cairo_t *pgtk_begin_cr_clip (struct frame *f);
-extern void pgtk_end_cr_clip (struct frame *f);
+extern cairo_t *pgtk_begin_cr_clip (struct frame *);
+extern void pgtk_end_cr_clip (struct frame *);
 extern void pgtk_set_cr_source_with_gc_foreground (struct frame *, Emacs_GC *, bool);
 extern void pgtk_set_cr_source_with_gc_background (struct frame *, Emacs_GC *, bool);
 extern void pgtk_set_cr_source_with_color (struct frame *, unsigned long, bool);
-extern void pgtk_cr_draw_frame (cairo_t * cr, struct frame *f);
-extern void pgtk_cr_destroy_frame_context (struct frame *f);
-extern Lisp_Object pgtk_cr_export_frames (Lisp_Object frames, cairo_surface_type_t surface_type);
+extern void pgtk_cr_draw_frame (cairo_t *, struct frame *);
+extern void pgtk_cr_destroy_frame_context (struct frame *);
+extern Lisp_Object pgtk_cr_export_frames (Lisp_Object , cairo_surface_type_t);
 
 /* Defined in pgtkmenu.c */
-extern Lisp_Object pgtk_popup_dialog (struct frame *f, Lisp_Object header,
-                                      Lisp_Object contents);
-extern Lisp_Object pgtk_dialog_show (struct frame *f, Lisp_Object title,
-                                     Lisp_Object header,
-                                     const char **error_name);
+extern Lisp_Object pgtk_popup_dialog (struct frame *, Lisp_Object, Lisp_Object);
+extern Lisp_Object pgtk_dialog_show (struct frame *, Lisp_Object, Lisp_Object,
+                                     const char **);
 extern void initialize_frame_menubar (struct frame *);
 
 
@@ -612,44 +600,46 @@ extern void syms_of_pgtkselect (void);
 extern void syms_of_pgtkim (void);
 
 /* Initialization and marking implemented in pgtkterm.c */
-extern void init_pgtkterm (void);
 extern void mark_pgtkterm (void);
-extern void pgtk_delete_terminal (struct terminal *terminal);
+extern void pgtk_delete_terminal (struct terminal *);
 
-extern void pgtk_make_frame_visible (struct frame *f);
-extern void pgtk_make_frame_invisible (struct frame *f);
+extern void pgtk_make_frame_visible (struct frame *);
+extern void pgtk_make_frame_invisible (struct frame *);
 extern void pgtk_free_frame_resources (struct frame *);
-extern void pgtk_iconify_frame (struct frame *f);
-extern void pgtk_focus_frame (struct frame *f, bool noactivate);
-extern void pgtk_set_scroll_bar_default_width (struct frame *f);
-extern void pgtk_set_scroll_bar_default_height (struct frame *f);
-extern Lisp_Object pgtk_get_focus_frame (struct frame *frame);
+extern void pgtk_iconify_frame (struct frame *);
+extern void pgtk_focus_frame (struct frame *, bool);
+extern void pgtk_set_scroll_bar_default_width (struct frame *);
+extern void pgtk_set_scroll_bar_default_height (struct frame *);
+extern Lisp_Object pgtk_get_focus_frame (struct frame *);
 
-extern void pgtk_frame_rehighlight (struct pgtk_display_info *dpyinfo);
+extern void pgtk_frame_rehighlight (struct pgtk_display_info *);
 
 extern void pgtk_change_tab_bar_height (struct frame *, int);
 
-extern struct pgtk_display_info *check_pgtk_display_info (Lisp_Object object);
+extern struct pgtk_display_info *check_pgtk_display_info (Lisp_Object);
 
-extern void pgtk_default_font_parameter (struct frame *f, Lisp_Object parms);
+extern void pgtk_default_font_parameter (struct frame *, Lisp_Object);
 
-extern void pgtk_menu_set_in_use (bool in_use);
+extern void pgtk_menu_set_in_use (bool);
 
+/* Drag and drop functions used by Lisp.  */
+extern void pgtk_update_drop_status (Lisp_Object, Lisp_Object);
+extern void pgtk_finish_drop (Lisp_Object, Lisp_Object, Lisp_Object);
 
-extern void pgtk_enqueue_string (struct frame *f, gchar * str);
-extern void pgtk_enqueue_preedit (struct frame *f, Lisp_Object image_data);
-extern void pgtk_im_focus_in (struct frame *f);
-extern void pgtk_im_focus_out (struct frame *f);
-extern bool pgtk_im_filter_keypress (struct frame *f, GdkEventKey * ev);
-extern void pgtk_im_set_cursor_location (struct frame *f, int x, int y,
-                                         int width, int height);
-extern void pgtk_im_init (struct pgtk_display_info *dpyinfo);
-extern void pgtk_im_finish (struct pgtk_display_info *dpyinfo);
+extern void pgtk_enqueue_string (struct frame *, gchar *);
+extern void pgtk_enqueue_preedit (struct frame *, Lisp_Object);
+extern void pgtk_im_focus_in (struct frame *);
+extern void pgtk_im_focus_out (struct frame *);
+extern bool pgtk_im_filter_keypress (struct frame *, GdkEventKey *);
+extern void pgtk_im_set_cursor_location (struct frame *, int, int,
+                                         int, int);
+extern void pgtk_im_init (struct pgtk_display_info *);
+extern void pgtk_im_finish (struct pgtk_display_info *);
 
 extern bool xg_set_icon (struct frame *, Lisp_Object);
-extern bool xg_set_icon_from_xpm_data (struct frame *f, const char **data);
+extern bool xg_set_icon_from_xpm_data (struct frame *, const char **);
 
-extern bool pgtk_text_icon (struct frame *f, const char *icon_name);
+extern bool pgtk_text_icon (struct frame *, const char *);
 
 extern double pgtk_frame_scale_factor (struct frame *);
 extern int pgtk_emacs_to_gtk_modifiers (struct pgtk_display_info *, int);