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.

1 files changed, 234 insertions, 42 deletions

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)
-{
-}