droptarget: Redo

This is a huge reorganization of GtkDropTarget. I did not know how to
split this up, so it's unfortunately all one commit.

Highlights:

- Split GtkDropTarget into GtkDropTarget and GtkDropTargetAsync
  GtkDropTarget is the simple one that only works with GTypes and offers
  a synchronous interface.
  GtkDropTargetAsync retains the full old functionality and allows
  handling mime types.

- Drop events are handled differently
  Instead of picking a single drop target and sending all DND events to
  it, every event is sent to every drop target. The first one to handle
  the event gets to call gdk_drop_status(), further handlers do not
  interact with the GdkDrop.
  Of course, for the ultimate GDK_DROP_STARTING event, only the first
  one to accept the drop gets to handle it.
  This allows stacking DND event controllers that aren't necessarily
  interested in handling the event or that might decide later to drop
  it.

- Port all widgets to either of those
  Both have a somewhat changed API due to the new event handling.
  For the ones who should use the sync version, lots of cleanup was
  involved to operate on a sync API.

1 files changed, 58 insertions, 154 deletions

diff --git a/gtk/gtkcalendar.c b/gtk/gtkcalendar.c
index eb63b38db0..ec71a373cc 100644
--- a/gtk/gtkcalendar.c
+++ b/gtk/gtkcalendar.c
@@ -95,7 +95,7 @@
 #endif
 
 #include "gtkcalendar.h"
-#include "gtkdragdest.h"
+#include "gtkdroptarget.h"
 #include "gtkintl.h"
 #include "gtkmain.h"
 #include "gtkmarshalers.h"
@@ -285,17 +285,6 @@ static void     gtk_calendar_focus_controller_focus     (GtkEventController    *
                                                          GtkWidget             *widget);
 static void     gtk_calendar_state_flags_changed  (GtkWidget     *widget,
                                                    GtkStateFlags  previous_state);
-static gboolean gtk_calendar_drag_accept        (GtkDropTarget    *dest,
-                                                 GdkDrop          *drop,
-                                                 GtkCalendar      *calendar);
-static void     gtk_calendar_drag_leave         (GtkDropTarget    *dest,
-                                                 GdkDrop          *drop,
-                                                 GtkCalendar      *calendar);
-static gboolean gtk_calendar_drag_drop          (GtkDropTarget    *dest,
-                                                 GdkDrop          *drop,
-                                                 int               x,
-                                                 int               y,
-                                                 GtkCalendar      *calendar);
 
 
 static void calendar_invalidate_day     (GtkCalendar *widget,
@@ -321,6 +310,57 @@ static char    *default_monthname[12];
 G_DEFINE_TYPE_WITH_PRIVATE (GtkCalendar, gtk_calendar, GTK_TYPE_WIDGET)
 
 static void
+gtk_calendar_drag_notify_value (GtkDropTarget  *target,
+                                GParamSpec    **pspec,
+                                GtkCalendar    *calendar)
+{
+  GDate *date;
+  const GValue *value;
+
+  value = gtk_drop_target_get_value (target);
+  if (value == NULL)
+    return;
+
+  date = g_date_new ();
+  g_date_set_parse (date, g_value_get_string (value));
+  if (!g_date_valid (date))
+    gtk_drop_target_reject (target);
+  g_date_free (date);
+}
+
+static gboolean
+gtk_calendar_drag_drop (GtkDropTarget  *dest,
+                        const GValue   *value,
+                        double          x,
+                        double          y,
+                        GtkCalendar    *calendar)
+{
+  GDate *date;
+  GDateTime *datetime;
+
+  date = g_date_new ();
+  g_date_set_parse (date, g_value_get_string (value));
+
+  if (!g_date_valid (date))
+    {
+      g_warning ("Received invalid date data");
+      g_date_free (date);
+      return FALSE;
+    }
+
+  datetime = g_date_time_new_local (g_date_get_year (date),
+                                    g_date_get_month (date),
+                                    g_date_get_day (date),
+                                    0, 0, 0);
+  g_date_free (date);
+
+  gtk_calendar_select_day (calendar, datetime);
+  g_date_time_unref (datetime);
+
+  return TRUE;
+}
+
+static void
 gtk_calendar_dispose (GObject *object)
 {
   GtkCalendarPrivate *priv = gtk_calendar_get_instance_private (GTK_CALENDAR (object));
@@ -518,6 +558,7 @@ gtk_calendar_init (GtkCalendar *calendar)
   GtkWidget *widget = GTK_WIDGET (calendar);
   GtkEventController *controller;
   GtkGesture *gesture;
+  GtkDropTarget *target;
   gint i;
 #ifdef G_OS_WIN32
   wchar_t wbuffer[100];
@@ -535,7 +576,6 @@ gtk_calendar_init (GtkCalendar *calendar)
 #else
   gchar *week_start;
 #endif
-  GtkDropTarget *dest;
   int min_year_width;
   GDateTime *now;
 
@@ -718,14 +758,11 @@ gtk_calendar_init (GtkCalendar *calendar)
 
   priv->in_drag = 0;
 
-  dest = gtk_drop_target_new (gdk_content_formats_new_for_gtype (G_TYPE_STRING),
-                              GDK_ACTION_COPY);
-
-  g_signal_connect (dest, "accept", G_CALLBACK (gtk_calendar_drag_accept), calendar);
-  g_signal_connect (dest, "drag-leave", G_CALLBACK (gtk_calendar_drag_leave), calendar);
-  g_signal_connect (dest, "drag-drop", G_CALLBACK (gtk_calendar_drag_drop), calendar);
-
-  gtk_widget_add_controller (widget, GTK_EVENT_CONTROLLER (dest));
+  target = gtk_drop_target_new (G_TYPE_STRING, GDK_ACTION_COPY);
+  gtk_drop_target_set_preload (target, TRUE);
+  g_signal_connect (target, "notify::value", G_CALLBACK (gtk_calendar_drag_notify_value), calendar);
+  g_signal_connect (target, "drop", G_CALLBACK (gtk_calendar_drag_drop), calendar);
+  gtk_widget_add_controller (widget, GTK_EVENT_CONTROLLER (target));
 
   priv->year_before = 0;
 
@@ -1417,139 +1454,6 @@ gtk_calendar_state_flags_changed (GtkWidget     *widget,
     }
 }
 
-/* Get/set whether drag_motion requested the drag data and
- * drag_data_received should thus not actually insert the data,
- * since the data doesn’t result from a drop.
- */
-static void
-set_status_pending (GdkDrop       *drop,
-                    GdkDragAction  suggested_action)
-{
-  g_object_set_data (G_OBJECT (drop),
-                     I_("gtk-calendar-status-pending"),
-                     GINT_TO_POINTER (suggested_action));
-}
-
-static GdkDragAction
-get_status_pending (GdkDrop *drop)
-{
-  return GPOINTER_TO_INT (g_object_get_data (G_OBJECT (drop),
-                                             "gtk-calendar-status-pending"));
-}
-
-static void
-gtk_calendar_drag_leave (GtkDropTarget *dest,
-                         GdkDrop       *drop,
-                         GtkCalendar   *calendar)
-{
-}
-
-static void
-got_text (GObject      *source,
-          GAsyncResult *result,
-          gpointer      data)
-{
-  GtkDropTarget *dest = GTK_DROP_TARGET (data);
-  GtkCalendar *calendar = GTK_CALENDAR (gtk_event_controller_get_widget (GTK_EVENT_CONTROLLER (dest)));
-  GdkDrop *drop = GDK_DROP (source);
-  gchar *str;
-  GDate *date;
-  GDateTime *datetime;
-  GdkDragAction suggested_action;
-
-  suggested_action = get_status_pending (drop);
-  set_status_pending (drop, 0);
-
-  str = gdk_drop_read_text_finish (drop, result, NULL);
-
-  if (suggested_action)
-    {
-      if (str)
-        {
-          date = g_date_new ();
-          g_date_set_parse (date, str);
-          if (!g_date_valid (date))
-              suggested_action = 0;
-          g_date_free (date);
-          g_free (str);
-        }
-      else
-        suggested_action = 0;
-      gdk_drop_status (drop, suggested_action);
-      if (suggested_action == 0)
-        gtk_drop_target_deny_drop (dest, drop);
-      return;
-    }
-
-  date = g_date_new ();
-  if (str)
-    {
-      g_date_set_parse (date, str);
-      g_free (str);
-    }
-
-  if (!g_date_valid (date))
-    {
-      g_warning ("Received invalid date data");
-      g_date_free (date);
-      gdk_drop_finish (drop, 0);
-      gtk_drop_target_deny_drop (dest, drop);
-      return;
-    }
-
-  datetime = g_date_time_new_local (g_date_get_year (date),
-                                    g_date_get_month (date),
-                                    g_date_get_day (date),
-                                    0, 0, 0);
-  g_date_free (date);
-
-  gdk_drop_finish (drop, suggested_action);
-
-  gtk_calendar_select_day (calendar, datetime);
-  g_date_time_unref (datetime);
-}
-
-static gboolean
-gtk_calendar_drag_accept (GtkDropTarget *dest,
-                          GdkDrop       *drop,
-                          GtkCalendar   *calendar)
-{
-  const char *target;
-
-  target = gtk_drop_target_find_mimetype (dest);
-  if (!target || gdk_drop_get_actions (drop) == 0)
-    {
-      gdk_drop_status (drop, 0);
-      return FALSE;
-    }
-  else if (get_status_pending (drop) == 0)
-    {
-      set_status_pending (drop, gdk_drop_get_actions (drop));
-      gdk_drop_read_text_async (drop, NULL, got_text, dest);
-    }
-  return TRUE;
-}
-
-static gboolean
-gtk_calendar_drag_drop (GtkDropTarget  *dest,
-                        GdkDrop        *drop,
-                        int             x,
-                        int             y,
-                        GtkCalendar    *calendar)
-{
-  const char *target;
-
-  target = gtk_drop_target_find_mimetype (dest);
-  if (target != NULL)
-    {
-      set_status_pending (drop, 0);
-      gdk_drop_read_text_async (drop, NULL, got_text, dest);
-      return TRUE;
-    }
-
-  return FALSE;
-}
-
 
 /****************************************
  *              Public API              *