gtk2/gtk/gtkselectionmodel.c
Benjamin Otte 541aaa2392 selectionmodel: Add unselect_rest argument to select_callback
This is not just about consistency with other functions.

It is about avoiding reentrancy problems.

GtkListBase first doing an unselect_all() will then force the
SelectionModel to consider a state where all items are unselected
(and potentially deciding to autoselect one) and then cause a
"selection-changed" emission that unselects all items and potentially
updates all the list item widgets in the GtkListBase to the unselected
state.

After this, GtkListBase selects new items, but to the SelectionModel and
the list item widgets this looks like an enitrely new operation and
there is no way to associate it with the previous state, so the
SelectionModel cannot undo any previous actions it took when
unselecting.
And all listitem widgets will now think they were just selected and
start running animations about selecting.
2020-06-08 19:06:56 +02:00

448 lines
15 KiB
C

/*
* Copyright © 2018 Benjamin Otte
*
* 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 2.1 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/>.
*
* Authors: Benjamin Otte <otte@gnome.org>
*/
#include "config.h"
#include "gtkselectionmodel.h"
#include "gtkintl.h"
#include "gtkmarshalers.h"
/**
* SECTION:gtkselectionmodel
* @Title: GtkSelectionModel
* @Short_description: An extension of the list model interface that handles selections
* @See_also: #GListModel, #GtkSingleSelection
*
* #GtkSelectionModel is an interface that extends the #GListModel interface by adding
* support for selections. This support is then used by widgets using list models to add
* the ability to select and unselect various items.
*
* GTK provides default implementations of the mode common selection modes such as
* #GtkSingleSelection, so you will only need to implement this interface if you want
* detailed control about how selections should be handled.
*
* A #GtkSelectionModel supports a single boolean per item indicating if an item is selected
* or not. This can be queried via gtk_selection_model_is_selected(). When the selected
* state of one or more items changes, the model will emit the
* #GtkSelectionModel::selection-changed signal by calling the
* gtk_selection_model_selection_changed() function. The positions given in that signal
* may have their selection state changed, though that is not a requirement.
* If new items added to the model via the #GListModel::items-changed signal are selected
* or not is up to the implementation.
*
* Note that items added via #GListModel::items-changed may already be selected
* and no #GtkSelectionModel::selection-changed will be emitted for them. So to
* track which items are selected, it is necessary to listen to both signals.
*
* Additionally, the interface can expose functionality to select and unselect items.
* If these functions are implemented, GTK's list widgets will allow users to select and
* unselect items. However, #GtkSelectionModels are free to only implement them
* partially or not at all. In that case the widgets will not support the unimplemented
* operations.
*
* When selecting or unselecting is supported by a model, the return values of the
* selection functions do NOT indicate if selection or unselection happened. They are
* only meant to indicate complete failure, like when this mode of selecting is not
* supported by the model.
*
* Selections may happen asynchronously, so the only reliable way to find out when an
* item was selected is to listen to the signals that indicate selection.
*/
G_DEFINE_INTERFACE (GtkSelectionModel, gtk_selection_model, G_TYPE_LIST_MODEL)
enum {
SELECTION_CHANGED,
LAST_SIGNAL
};
static guint signals[LAST_SIGNAL] = { 0 };
static gboolean
gtk_selection_model_default_is_selected (GtkSelectionModel *model,
guint position)
{
return FALSE;
}
static gboolean
gtk_selection_model_default_select_item (GtkSelectionModel *model,
guint position,
gboolean unselect_rest)
{
return FALSE;
}
static gboolean
gtk_selection_model_default_unselect_item (GtkSelectionModel *model,
guint position)
{
return FALSE;
}
static gboolean
gtk_selection_model_default_select_range (GtkSelectionModel *model,
guint position,
guint n_items,
gboolean unselect_rest)
{
return FALSE;
}
static gboolean
gtk_selection_model_default_unselect_range (GtkSelectionModel *model,
guint position,
guint n_items)
{
return FALSE;
}
static gboolean
gtk_selection_model_default_select_callback (GtkSelectionModel *model,
gboolean unselect_rest,
GtkSelectionCallback callback,
gpointer data)
{
return FALSE;
}
static gboolean
gtk_selection_model_default_unselect_callback (GtkSelectionModel *model,
GtkSelectionCallback callback,
gpointer data)
{
return FALSE;
}
static gboolean
gtk_selection_model_default_select_all (GtkSelectionModel *model)
{
return gtk_selection_model_select_range (model, 0, g_list_model_get_n_items (G_LIST_MODEL (model)), FALSE);
}
static gboolean
gtk_selection_model_default_unselect_all (GtkSelectionModel *model)
{
return gtk_selection_model_unselect_range (model, 0, g_list_model_get_n_items (G_LIST_MODEL (model)));
}
static void
gtk_selection_model_default_query_range (GtkSelectionModel *model,
guint position,
guint *start_range,
guint *n_items,
gboolean *selected)
{
*start_range = position;
if (position >= g_list_model_get_n_items (G_LIST_MODEL (model)))
{
*n_items = 0;
*selected = FALSE;
}
else
{
*n_items = 1;
*selected = gtk_selection_model_is_selected (model, position);
}
}
static void
gtk_selection_model_default_init (GtkSelectionModelInterface *iface)
{
iface->is_selected = gtk_selection_model_default_is_selected;
iface->select_item = gtk_selection_model_default_select_item;
iface->unselect_item = gtk_selection_model_default_unselect_item;
iface->select_range = gtk_selection_model_default_select_range;
iface->unselect_range = gtk_selection_model_default_unselect_range;
iface->select_all = gtk_selection_model_default_select_all;
iface->unselect_all = gtk_selection_model_default_unselect_all;
iface->select_callback = gtk_selection_model_default_select_callback;
iface->unselect_callback = gtk_selection_model_default_unselect_callback;
iface->query_range = gtk_selection_model_default_query_range;
/**
* GtkSelectionModel::selection-changed
* @model: a #GtkSelectionModel
* @position: The first item that may have changed
* @n_items: number of items with changes
*
* Emitted when the selection state of some of the items in @model changes.
*
* Note that this signal does not specify the new selection state of the items,
* they need to be queried manually.
* It is also not necessary for a model to change the selection state of any of
* the items in the selection model, though it would be rather useless to emit
* such a signal.
*/
signals[SELECTION_CHANGED] =
g_signal_new ("selection-changed",
GTK_TYPE_SELECTION_MODEL,
G_SIGNAL_RUN_LAST,
0,
NULL, NULL,
_gtk_marshal_VOID__UINT_UINT,
G_TYPE_NONE, 2, G_TYPE_UINT, G_TYPE_UINT);
g_signal_set_va_marshaller (signals[SELECTION_CHANGED],
GTK_TYPE_SELECTION_MODEL,
_gtk_marshal_VOID__UINT_UINTv);
}
/**
* gtk_selection_model_is_selected:
* @model: a #GtkSelectionModel
* @position: the position of the item to query
*
* Checks if the given item is selected.
*
* Returns: %TRUE if the item is selected
**/
gboolean
gtk_selection_model_is_selected (GtkSelectionModel *model,
guint position)
{
GtkSelectionModelInterface *iface;
g_return_val_if_fail (GTK_IS_SELECTION_MODEL (model), 0);
iface = GTK_SELECTION_MODEL_GET_IFACE (model);
return iface->is_selected (model, position);
}
/**
* gtk_selection_model_select_item:
* @model: a #GtkSelectionModel
* @position: the position of the item to select
* @unselect_rest: whether previously selected items should be unselected
*
* Requests to select an item in the model.
*/
gboolean
gtk_selection_model_select_item (GtkSelectionModel *model,
guint position,
gboolean unselect_rest)
{
GtkSelectionModelInterface *iface;
g_return_val_if_fail (GTK_IS_SELECTION_MODEL (model), 0);
iface = GTK_SELECTION_MODEL_GET_IFACE (model);
return iface->select_item (model, position, unselect_rest);
}
/**
* gtk_selection_model_unselect_item:
* @model: a #GtkSelectionModel
* @position: the position of the item to unselect
*
* Requests to unselect an item in the model.
*/
gboolean
gtk_selection_model_unselect_item (GtkSelectionModel *model,
guint position)
{
GtkSelectionModelInterface *iface;
g_return_val_if_fail (GTK_IS_SELECTION_MODEL (model), 0);
iface = GTK_SELECTION_MODEL_GET_IFACE (model);
return iface->unselect_item (model, position);
}
/**
* gtk_selection_model_select_range:
* @model: a #GtkSelectionModel
* @position: the first item to select
* @n_items: the number of items to select
* @unselect_rest: whether previously selected items should be unselected
*
* Requests to select a range of items in the model.
*/
gboolean
gtk_selection_model_select_range (GtkSelectionModel *model,
guint position,
guint n_items,
gboolean unselect_rest)
{
GtkSelectionModelInterface *iface;
g_return_val_if_fail (GTK_IS_SELECTION_MODEL (model), 0);
iface = GTK_SELECTION_MODEL_GET_IFACE (model);
return iface->select_range (model, position, n_items, unselect_rest);
}
/**
* gtk_selection_model_unselect_range:
* @model: a #GtkSelectionModel
* @position: the first item to unselect
* @n_items: the number of items to unselect
*
* Requests to unselect a range of items in the model.
*/
gboolean
gtk_selection_model_unselect_range (GtkSelectionModel *model,
guint position,
guint n_items)
{
GtkSelectionModelInterface *iface;
g_return_val_if_fail (GTK_IS_SELECTION_MODEL (model), 0);
iface = GTK_SELECTION_MODEL_GET_IFACE (model);
return iface->unselect_range (model, position, n_items);
}
/**
* gtk_selection_model_select_all:
* @model: a #GtkSelectionModel
*
* Requests to select all items in the model.
*/
gboolean
gtk_selection_model_select_all (GtkSelectionModel *model)
{
GtkSelectionModelInterface *iface;
g_return_val_if_fail (GTK_IS_SELECTION_MODEL (model), 0);
iface = GTK_SELECTION_MODEL_GET_IFACE (model);
return iface->select_all (model);
}
/**
* gtk_selection_model_unselect_all:
* @model: a #GtkSelectionModel
*
* Requests to unselect all items in the model.
*/
gboolean
gtk_selection_model_unselect_all (GtkSelectionModel *model)
{
GtkSelectionModelInterface *iface;
g_return_val_if_fail (GTK_IS_SELECTION_MODEL (model), 0);
iface = GTK_SELECTION_MODEL_GET_IFACE (model);
return iface->unselect_all (model);
}
/**
* gtk_selection_model_select_callback:
* @model: a #GtkSelectionModel
* @unselect_rest: whether previously selected items should be unselected
* @callback: (scope call): a #GtkSelectionCallback to determine items to select
* @data: data to pass to @callback
*
* Requests to select all items for which @callback returns
* @selected as TRUE.
*/
gboolean
gtk_selection_model_select_callback (GtkSelectionModel *model,
gboolean unselect_rest,
GtkSelectionCallback callback,
gpointer data)
{
g_return_val_if_fail (GTK_IS_SELECTION_MODEL (model), FALSE);
return GTK_SELECTION_MODEL_GET_IFACE (model)->select_callback (model, unselect_rest, callback, data);
}
/**
* gtk_selection_model_unselect_callback:
* @model: a #GtkSelectionModel
* @callback: (scope call): a #GtkSelectionCallback to determine items to select
* @data: data to pass to @callback
*
* Requests to unselect all items for which @callback returns
* @selected as TRUE.
*/
gboolean
gtk_selection_model_unselect_callback (GtkSelectionModel *model,
GtkSelectionCallback callback,
gpointer data)
{
g_return_val_if_fail (GTK_IS_SELECTION_MODEL (model), FALSE);
return GTK_SELECTION_MODEL_GET_IFACE (model)->unselect_callback (model, callback, data);
}
/**
* gtk_selection_model_query_range:
* @model: a #GtkSelectionModel
* @position: the position inside the range
* @start_range: (out): returns the position of the first element of the range
* @n_items: (out): returns the size of the range
* @selected: (out): returns whether items in @range are selected
*
* This function allows to query the selection status of multiple elements at once.
* It is passed a position and returns a range of elements of uniform selection status.
*
* If @position is greater than the number of items in @model, @n_items is set to 0.
* Otherwise the returned range is guaranteed to include the passed-in position, so
* @n_items will be >= 1.
*
* Positions directly adjacent to the returned range may have the same selection
* status as the returned range.
*
* This is an optimization function to make iterating over a model faster when few
* items are selected. However, it is valid behavior for implementations to use a
* naive implementation that only ever returns a single element.
*/
void
gtk_selection_model_query_range (GtkSelectionModel *model,
guint position,
guint *start_range,
guint *n_items,
gboolean *selected)
{
GtkSelectionModelInterface *iface;
g_return_if_fail (GTK_IS_SELECTION_MODEL (model));
g_return_if_fail (start_range != NULL);
g_return_if_fail (n_items != NULL);
g_return_if_fail (selected != NULL);
iface = GTK_SELECTION_MODEL_GET_IFACE (model);
return iface->query_range (model, position, start_range, n_items, selected);
}
/**
* gtk_selection_model_selection_changed:
* @model: a #GtkSelectionModel
* @position: the first changed item
* @n_items: the number of changed items
*
* Helper function for implementations of #GtkSelectionModel.
* Call this when a the selection changes to emit the ::selection-changed
* signal.
*/
void
gtk_selection_model_selection_changed (GtkSelectionModel *model,
guint position,
guint n_items)
{
g_return_if_fail (GTK_IS_SELECTION_MODEL (model));
g_return_if_fail (n_items > 0);
g_return_if_fail (position + n_items <= g_list_model_get_n_items (G_LIST_MODEL (model)));
g_signal_emit (model, signals[SELECTION_CHANGED], 0, position, n_items);
}