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Learning_GTK4_tree/gdk/gdkdrag.c

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/* GDK - The GIMP Drawing Kit
* Copyright (C) 1995-1999 Peter Mattis, Spencer Kimball and Josh MacDonald
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see <http://www.gnu.org/licenses/>.
*/
/*
* Modified by the GTK+ Team and others 1997-2000. See the AUTHORS
* file for a list of people on the GTK+ Team. See the ChangeLog
* files for a list of changes. These files are distributed with
* GTK+ at ftp://ftp.gtk.org/pub/gtk/.
*/
/**
* GdkDrag:
*
* The `GdkDrag` object represents the source of an ongoing DND operation.
*
* A `GdkDrag` is created when a drag is started, and stays alive for duration of
* the DND operation. After a drag has been started with [func@Gdk.Drag.begin],
* the caller gets informed about the status of the ongoing drag operation
* with signals on the `GdkDrag` object.
*
* GTK provides a higher level abstraction based on top of these functions,
* and so they are not normally needed in GTK applications. See the
* "Drag and Drop" section of the GTK documentation for more information.
*/
#include "config.h"
#include "gdkdragprivate.h"
#include "gdkdisplay.h"
#include "gdksurface.h"
#include <glib/gi18n-lib.h>
#include "gdkcontentformats.h"
#include "gdkcontentprovider.h"
#include "gdkcontentserializer.h"
#include "gdkcursor.h"
#include "gdkenumtypes.h"
#include "gdkeventsprivate.h"
static struct {
GdkDragAction action;
const char *name;
GdkCursor *cursor;
} drag_cursors[] = {
{ GDK_ACTION_ASK, "dnd-ask", NULL },
{ GDK_ACTION_COPY, "dnd-copy", NULL },
{ GDK_ACTION_MOVE, "dnd-move", NULL },
{ GDK_ACTION_LINK, "dnd-link", NULL },
{ 0, "dnd-none", NULL },
};
enum {
PROP_0,
PROP_CONTENT,
PROP_DEVICE,
PROP_DISPLAY,
PROP_FORMATS,
PROP_SELECTED_ACTION,
PROP_ACTIONS,
PROP_SURFACE,
N_PROPERTIES
};
enum {
CANCEL,
DROP_PERFORMED,
DND_FINISHED,
N_SIGNALS
};
typedef struct _GdkDragPrivate GdkDragPrivate;
struct _GdkDragPrivate {
GdkSurface *surface;
GdkDisplay *display;
GdkDevice *device;
GdkContentFormats *formats;
GdkContentProvider *content;
GdkDragAction actions;
GdkDragAction selected_action;
guint drop_done : 1; /* Whether gdk_drag_drop_done() was performed */
};
static GParamSpec *properties[N_PROPERTIES] = { NULL, };
static guint signals[N_SIGNALS] = { 0 };
static GList *drags = NULL;
G_DEFINE_ABSTRACT_TYPE_WITH_PRIVATE (GdkDrag, gdk_drag, G_TYPE_OBJECT)
/**
* gdk_drag_get_display: (attributes org.gtk.Method.get_property=display)
* @drag: a `GdkDrag`
*
* Gets the `GdkDisplay` that the drag object was created for.
*
* Returns: (transfer none): a `GdkDisplay`
*/
GdkDisplay *
gdk_drag_get_display (GdkDrag *drag)
{
GdkDragPrivate *priv = gdk_drag_get_instance_private (drag);
g_return_val_if_fail (GDK_IS_DRAG (drag), NULL);
return priv->display;
}
/**
* gdk_drag_get_formats: (attributes org.gtk.Method.get_property=formats)
* @drag: a `GdkDrag`
*
* Retrieves the formats supported by this `GdkDrag` object.
*
* Returns: (transfer none): a `GdkContentFormats`
*/
GdkContentFormats *
gdk_drag_get_formats (GdkDrag *drag)
{
GdkDragPrivate *priv = gdk_drag_get_instance_private (drag);
g_return_val_if_fail (GDK_IS_DRAG (drag), NULL);
return priv->formats;
}
/**
* gdk_drag_get_actions: (attributes org.gtk.Method.get_property=actions)
* @drag: a `GdkDrag`
*
* Determines the bitmask of possible actions proposed by the source.
*
* Returns: the `GdkDragAction` flags
*/
GdkDragAction
gdk_drag_get_actions (GdkDrag *drag)
{
GdkDragPrivate *priv = gdk_drag_get_instance_private (drag);
g_return_val_if_fail (GDK_IS_DRAG (drag), 0);
return priv->actions;
}
/**
* gdk_drag_get_selected_action: (attributes org.gtk.Method.get_property=selected-action)
* @drag: a `GdkDrag`
*
* Determines the action chosen by the drag destination.
*
* Returns: a `GdkDragAction` value
*/
GdkDragAction
gdk_drag_get_selected_action (GdkDrag *drag)
{
GdkDragPrivate *priv = gdk_drag_get_instance_private (drag);
g_return_val_if_fail (GDK_IS_DRAG (drag), 0);
return priv->selected_action;
}
/**
* gdk_drag_get_device: (attributes org.gtk.Method.get_property=device)
* @drag: a `GdkDrag`
*
* Returns the `GdkDevice` associated to the `GdkDrag` object.
*
* Returns: (transfer none): The `GdkDevice` associated to @drag.
*/
GdkDevice *
gdk_drag_get_device (GdkDrag *drag)
{
GdkDragPrivate *priv = gdk_drag_get_instance_private (drag);
g_return_val_if_fail (GDK_IS_DRAG (drag), NULL);
return priv->device;
}
/**
* gdk_drag_get_content: (attributes org.gtk.Method.get_property=content)
* @drag: a `GdkDrag`
*
* Returns the `GdkContentProvider` associated to the `GdkDrag` object.
*
* Returns: (transfer none): The `GdkContentProvider` associated to @drag.
*/
GdkContentProvider *
gdk_drag_get_content (GdkDrag *drag)
{
GdkDragPrivate *priv = gdk_drag_get_instance_private (drag);
g_return_val_if_fail (GDK_IS_DRAG (drag), NULL);
return priv->content;
}
/**
* gdk_drag_get_surface: (attributes org.gtk.Method.get_property=surface)
* @drag: a `GdkDrag`
*
* Returns the `GdkSurface` where the drag originates.
*
* Returns: (transfer none): The `GdkSurface` where the drag originates
*/
GdkSurface *
gdk_drag_get_surface (GdkDrag *drag)
{
GdkDragPrivate *priv = gdk_drag_get_instance_private (drag);
g_return_val_if_fail (GDK_IS_DRAG (drag), NULL);
return priv->surface;
}
static void
gdk_drag_init (GdkDrag *drag)
{
drags = g_list_prepend (drags, drag);
}
static void
gdk_drag_set_property (GObject *gobject,
guint prop_id,
const GValue *value,
GParamSpec *pspec)
{
GdkDrag *drag = GDK_DRAG (gobject);
GdkDragPrivate *priv = gdk_drag_get_instance_private (drag);
switch (prop_id)
{
case PROP_CONTENT:
priv->content = g_value_dup_object (value);
if (priv->content)
{
g_assert (priv->formats == NULL);
priv->formats = gdk_content_provider_ref_formats (priv->content);
}
break;
case PROP_DEVICE:
priv->device = g_value_dup_object (value);
g_assert (priv->device != NULL);
priv->display = gdk_device_get_display (priv->device);
break;
case PROP_FORMATS:
if (priv->formats)
{
GdkContentFormats *override = g_value_dup_boxed (value);
if (override)
{
gdk_content_formats_unref (priv->formats);
priv->formats = override;
}
}
else
{
priv->formats = g_value_dup_boxed (value);
g_assert (priv->formats != NULL);
}
break;
case PROP_SELECTED_ACTION:
{
GdkDragAction action = g_value_get_flags (value);
gdk_drag_set_selected_action (drag, action);
}
break;
case PROP_ACTIONS:
{
GdkDragAction actions = g_value_get_flags (value);
gdk_drag_set_actions (drag, actions);
}
break;
case PROP_SURFACE:
priv->surface = g_value_dup_object (value);
g_assert (priv->surface != NULL);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (gobject, prop_id, pspec);
break;
}
}
static void
gdk_drag_get_property (GObject *gobject,
guint prop_id,
GValue *value,
GParamSpec *pspec)
{
GdkDrag *drag = GDK_DRAG (gobject);
GdkDragPrivate *priv = gdk_drag_get_instance_private (drag);
switch (prop_id)
{
case PROP_CONTENT:
g_value_set_object (value, priv->content);
break;
case PROP_DEVICE:
g_value_set_object (value, priv->device);
break;
case PROP_DISPLAY:
g_value_set_object (value, priv->display);
break;
case PROP_FORMATS:
g_value_set_boxed (value, priv->formats);
break;
case PROP_SELECTED_ACTION:
g_value_set_flags (value, priv->selected_action);
break;
case PROP_ACTIONS:
g_value_set_flags (value, priv->actions);
break;
case PROP_SURFACE:
g_value_set_object (value, priv->surface);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (gobject, prop_id, pspec);
break;
}
}
static void
gdk_drag_finalize (GObject *object)
{
GdkDrag *drag = GDK_DRAG (object);
GdkDragPrivate *priv = gdk_drag_get_instance_private (drag);
drags = g_list_remove (drags, drag);
g_clear_object (&priv->content);
g_clear_pointer (&priv->formats, gdk_content_formats_unref);
g_clear_object (&priv->surface);
G_OBJECT_CLASS (gdk_drag_parent_class)->finalize (object);
}
static void
gdk_drag_class_init (GdkDragClass *klass)
{
GObjectClass *object_class = G_OBJECT_CLASS (klass);
object_class->get_property = gdk_drag_get_property;
object_class->set_property = gdk_drag_set_property;
object_class->finalize = gdk_drag_finalize;
/**
* GdkDrag:content: (attributes org.gtk.Property.get=gdk_drag_get_content)
*
* The `GdkContentProvider`.
*/
properties[PROP_CONTENT] =
g_param_spec_object ("content", NULL, NULL,
GDK_TYPE_CONTENT_PROVIDER,
G_PARAM_READWRITE |
G_PARAM_CONSTRUCT_ONLY |
G_PARAM_STATIC_STRINGS |
G_PARAM_EXPLICIT_NOTIFY);
/**
* GdkDrag:device: (attributes org.gtk.Property.get=gdk_drag_get_device)
*
* The `GdkDevice` that is performing the drag.
*/
properties[PROP_DEVICE] =
g_param_spec_object ("device", NULL, NULL,
GDK_TYPE_DEVICE,
G_PARAM_READWRITE |
G_PARAM_CONSTRUCT_ONLY |
G_PARAM_STATIC_STRINGS |
G_PARAM_EXPLICIT_NOTIFY);
/**
* GdkDrag:display: (attributes org.gtk.Property.get=gdk_drag_get_display)
*
* The `GdkDisplay` that the drag belongs to.
*/
properties[PROP_DISPLAY] =
g_param_spec_object ("display", NULL, NULL,
GDK_TYPE_DISPLAY,
G_PARAM_READABLE |
G_PARAM_STATIC_STRINGS |
G_PARAM_EXPLICIT_NOTIFY);
/**
* GdkDrag:formats: (attributes org.gtk.Property.get=gdk_drag_get_formats)
*
* The possible formats that the drag can provide its data in.
*/
properties[PROP_FORMATS] =
g_param_spec_boxed ("formats", NULL, NULL,
GDK_TYPE_CONTENT_FORMATS,
G_PARAM_READWRITE |
G_PARAM_CONSTRUCT_ONLY |
G_PARAM_STATIC_STRINGS |
G_PARAM_EXPLICIT_NOTIFY);
/**
* GdkDrag:selected-action: (attributes org.gtk.Property.get=gdk_drag_get_selected_action)
*
* The currently selected action of the drag.
*/
properties[PROP_SELECTED_ACTION] =
g_param_spec_flags ("selected-action", NULL, NULL,
GDK_TYPE_DRAG_ACTION,
0,
G_PARAM_READWRITE |
G_PARAM_STATIC_STRINGS |
G_PARAM_EXPLICIT_NOTIFY);
/**
* GdkDrag:actions: (attributes org.gtk.Property.get=gdk_drag_get_actions)
*
* The possible actions of this drag.
*/
properties[PROP_ACTIONS] =
g_param_spec_flags ("actions", NULL, NULL,
GDK_TYPE_DRAG_ACTION,
0,
G_PARAM_READWRITE |
G_PARAM_STATIC_STRINGS |
G_PARAM_EXPLICIT_NOTIFY);
/**
* GdkDrag:surface: (attributes org.gtk.Property.get=gdk_drag_get_surface)
*
* The surface where the drag originates.
*/
properties[PROP_SURFACE] =
g_param_spec_object ("surface", NULL, NULL,
GDK_TYPE_SURFACE,
G_PARAM_READWRITE |
G_PARAM_CONSTRUCT_ONLY |
G_PARAM_STATIC_STRINGS |
G_PARAM_EXPLICIT_NOTIFY);
/**
* GdkDrag::cancel:
* @drag: The object on which the signal is emitted
* @reason: The reason the drag was cancelled
*
* Emitted when the drag operation is cancelled.
*/
signals[CANCEL] =
g_signal_new (g_intern_static_string ("cancel"),
G_TYPE_FROM_CLASS (object_class),
G_SIGNAL_RUN_LAST,
G_STRUCT_OFFSET (GdkDragClass, cancel),
NULL, NULL,
NULL,
G_TYPE_NONE, 1, GDK_TYPE_DRAG_CANCEL_REASON);
/**
* GdkDrag::drop-performed:
* @drag: The object on which the signal is emitted
*
* Emitted when the drop operation is performed on an accepting client.
*/
signals[DROP_PERFORMED] =
g_signal_new (g_intern_static_string ("drop-performed"),
G_TYPE_FROM_CLASS (object_class),
G_SIGNAL_RUN_LAST,
G_STRUCT_OFFSET (GdkDragClass, drop_performed),
NULL, NULL,
NULL,
G_TYPE_NONE, 0);
/**
* GdkDrag::dnd-finished:
* @drag: The object on which the signal is emitted
*
* Emitted when the destination side has finished reading all data.
*
* The drag object can now free all miscellaneous data.
*/
signals[DND_FINISHED] =
g_signal_new (g_intern_static_string ("dnd-finished"),
G_TYPE_FROM_CLASS (object_class),
G_SIGNAL_RUN_LAST,
G_STRUCT_OFFSET (GdkDragClass, dnd_finished),
NULL, NULL,
NULL,
G_TYPE_NONE, 0);
g_object_class_install_properties (object_class, N_PROPERTIES, properties);
}
static void
gdk_drag_write_done (GObject *content,
GAsyncResult *result,
gpointer task)
{
GError *error = NULL;
if (gdk_content_provider_write_mime_type_finish (GDK_CONTENT_PROVIDER (content), result, &error))
g_task_return_boolean (task, TRUE);
else
g_task_return_error (task, error);
g_object_unref (task);
}
static void
gdk_drag_write_serialize_done (GObject *content,
GAsyncResult *result,
gpointer task)
{
GError *error = NULL;
if (gdk_content_serialize_finish (result, &error))
g_task_return_boolean (task, TRUE);
else
g_task_return_error (task, error);
g_object_unref (task);
}
void
gdk_drag_write_async (GdkDrag *drag,
const char *mime_type,
GOutputStream *stream,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
GdkDragPrivate *priv = gdk_drag_get_instance_private (drag);
GdkContentFormats *formats, *mime_formats;
GTask *task;
GType gtype;
g_return_if_fail (GDK_IS_DRAG (drag));
g_return_if_fail (priv->content);
g_return_if_fail (mime_type != NULL);
g_return_if_fail (mime_type == g_intern_string (mime_type));
g_return_if_fail (G_IS_OUTPUT_STREAM (stream));
g_return_if_fail (cancellable == NULL || G_IS_CANCELLABLE (cancellable));
g_return_if_fail (callback != NULL);
task = g_task_new (drag, cancellable, callback, user_data);
g_task_set_priority (task, io_priority);
g_task_set_source_tag (task, gdk_drag_write_async);
formats = gdk_content_provider_ref_formats (priv->content);
if (gdk_content_formats_contain_mime_type (formats, mime_type))
{
gdk_content_provider_write_mime_type_async (priv->content,
mime_type,
stream,
io_priority,
cancellable,
gdk_drag_write_done,
task);
gdk_content_formats_unref (formats);
return;
}
mime_formats = gdk_content_formats_new ((const char *[2]) { mime_type, NULL }, 1);
mime_formats = gdk_content_formats_union_serialize_gtypes (mime_formats);
gtype = gdk_content_formats_match_gtype (formats, mime_formats);
if (gtype != G_TYPE_INVALID)
{
GValue value = G_VALUE_INIT;
GError *error = NULL;
g_assert (gtype != G_TYPE_INVALID);
g_value_init (&value, gtype);
if (gdk_content_provider_get_value (priv->content, &value, &error))
{
gdk_content_serialize_async (stream,
mime_type,
&value,
io_priority,
cancellable,
gdk_drag_write_serialize_done,
g_object_ref (task));
}
else
{
g_task_return_error (task, error);
}
g_value_unset (&value);
}
else
{
g_task_return_new_error (task, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
_("No compatible formats to transfer clipboard contents."));
}
gdk_content_formats_unref (mime_formats);
gdk_content_formats_unref (formats);
g_object_unref (task);
}
gboolean
gdk_drag_write_finish (GdkDrag *drag,
GAsyncResult *result,
GError **error)
{
g_return_val_if_fail (g_task_is_valid (result, drag), FALSE);
g_return_val_if_fail (g_task_get_source_tag (G_TASK (result)) == gdk_drag_write_async, FALSE);
return g_task_propagate_boolean (G_TASK (result), error);
}
void
gdk_drag_set_actions (GdkDrag *drag,
GdkDragAction actions)
{
GdkDragPrivate *priv = gdk_drag_get_instance_private (drag);
if (priv->actions == actions)
return;
priv->actions = actions;
g_object_notify_by_pspec (G_OBJECT (drag), properties[PROP_ACTIONS]);
}
void
gdk_drag_set_selected_action (GdkDrag *drag,
GdkDragAction action)
{
GdkDragPrivate *priv = gdk_drag_get_instance_private (drag);
GdkCursor *cursor;
if (priv->selected_action == action)
return;
priv->selected_action = action;
cursor = gdk_drag_get_cursor (drag, action);
gdk_drag_set_cursor (drag, cursor);
g_object_notify_by_pspec (G_OBJECT (drag), properties[PROP_SELECTED_ACTION]);
}
/**
* gdk_drag_get_drag_surface:
* @drag: a `GdkDrag`
*
* Returns the surface on which the drag icon should be rendered
* during the drag operation.
*
* Note that the surface may not be available until the drag operation
* has begun. GDK will move the surface in accordance with the ongoing
* drag operation. The surface is owned by @drag and will be destroyed
* when the drag operation is over.
*
* Returns: (nullable) (transfer none): the drag surface
*/
GdkSurface *
gdk_drag_get_drag_surface (GdkDrag *drag)
{
g_return_val_if_fail (GDK_IS_DRAG (drag), NULL);
if (GDK_DRAG_GET_CLASS (drag)->get_drag_surface)
return GDK_DRAG_GET_CLASS (drag)->get_drag_surface (drag);
return NULL;
}
/**
* gdk_drag_set_hotspot:
* @drag: a `GdkDrag`
* @hot_x: x coordinate of the drag surface hotspot
* @hot_y: y coordinate of the drag surface hotspot
*
* Sets the position of the drag surface that will be kept
* under the cursor hotspot.
*
* Initially, the hotspot is at the top left corner of the drag surface.
*/
void
gdk_drag_set_hotspot (GdkDrag *drag,
int hot_x,
int hot_y)
{
g_return_if_fail (GDK_IS_DRAG (drag));
if (GDK_DRAG_GET_CLASS (drag)->set_hotspot)
GDK_DRAG_GET_CLASS (drag)->set_hotspot (drag, hot_x, hot_y);
}
/**
* gdk_drag_drop_done:
* @drag: a `GdkDrag`
* @success: whether the drag was ultimatively successful
*
* Informs GDK that the drop ended.
*
* Passing %FALSE for @success may trigger a drag cancellation
* animation.
*
* This function is called by the drag source, and should be the
* last call before dropping the reference to the @drag.
*
* The `GdkDrag` will only take the first [method@Gdk.Drag.drop_done]
* call as effective, if this function is called multiple times,
* all subsequent calls will be ignored.
*/
void
gdk_drag_drop_done (GdkDrag *drag,
gboolean success)
{
GdkDragPrivate *priv = gdk_drag_get_instance_private (drag);
g_return_if_fail (GDK_IS_DRAG (drag));
if (priv->drop_done)
return;
priv->drop_done = TRUE;
if (GDK_DRAG_GET_CLASS (drag)->drop_done)
GDK_DRAG_GET_CLASS (drag)->drop_done (drag, success);
}
void
gdk_drag_set_cursor (GdkDrag *drag,
GdkCursor *cursor)
{
g_return_if_fail (GDK_IS_DRAG (drag));
if (GDK_DRAG_GET_CLASS (drag)->set_cursor)
GDK_DRAG_GET_CLASS (drag)->set_cursor (drag, cursor);
}
void
gdk_drag_cancel (GdkDrag *drag,
GdkDragCancelReason reason)
{
g_return_if_fail (GDK_IS_DRAG (drag));
g_signal_emit (drag, signals[CANCEL], 0, reason);
}
gboolean
gdk_drag_handle_source_event (GdkEvent *event)
{
GdkDrag *drag;
GList *l;
for (l = drags; l; l = l->next)
{
drag = l->data;
if (!GDK_DRAG_GET_CLASS (drag)->handle_event)
continue;
if (GDK_DRAG_GET_CLASS (drag)->handle_event (drag, event))
return TRUE;
}
return FALSE;
}
GdkCursor *
gdk_drag_get_cursor (GdkDrag *drag,
GdkDragAction action)
{
int i;
for (i = 0 ; i < G_N_ELEMENTS (drag_cursors) - 1; i++)
if (drag_cursors[i].action == action)
break;
if (drag_cursors[i].cursor == NULL)
drag_cursors[i].cursor = gdk_cursor_new_from_name (drag_cursors[i].name, NULL);
return drag_cursors[i].cursor;
}
/**
* gdk_drag_action_is_unique:
* @action: a `GdkDragAction`
*
* Checks if @action represents a single action or includes
* multiple actions.
*
* When @action is 0 - ie no action was given, %TRUE
* is returned.
*
* Returns: %TRUE if exactly one action was given
*/
gboolean
gdk_drag_action_is_unique (GdkDragAction action)
{
return (action & (action - 1)) == 0;
}
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