gtk2/gtk/gtkselectionmodel.c
2020-08-21 15:29:34 +02:00

562 lines
18 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 "gtkbitset.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 most 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)
{
GtkBitset *bitset;
gboolean selected;
bitset = gtk_selection_model_get_selection_in_range (model, position, 1);
selected = gtk_bitset_contains (bitset, position);
gtk_bitset_unref (bitset);
return selected;
}
static GtkBitset *
gtk_selection_model_default_get_selection_in_range (GtkSelectionModel *model,
guint position,
guint n_items)
{
GtkBitset *bitset;
guint i;
bitset = gtk_bitset_new_empty ();
for (i = position; i < position + n_items; i++)
{
if (gtk_selection_model_is_selected (model, i))
gtk_bitset_add (bitset, i);
}
return bitset;
}
static gboolean
gtk_selection_model_default_select_item (GtkSelectionModel *model,
guint position,
gboolean unselect_rest)
{
GtkBitset *selected;
GtkBitset *mask;
gboolean result;
selected = gtk_bitset_new_empty ();
gtk_bitset_add (selected, position);
if (unselect_rest)
{
mask = gtk_bitset_new_empty ();
gtk_bitset_add_range (mask, 0, g_list_model_get_n_items (G_LIST_MODEL (model)));
}
else
{
mask = gtk_bitset_ref (selected);
}
result = gtk_selection_model_set_selection (model, selected, mask);
gtk_bitset_unref (selected);
gtk_bitset_unref (mask);
return result;
}
static gboolean
gtk_selection_model_default_unselect_item (GtkSelectionModel *model,
guint position)
{
GtkBitset *selected;
GtkBitset *mask;
gboolean result;
selected = gtk_bitset_new_empty ();
mask = gtk_bitset_new_empty ();
gtk_bitset_add (mask, position);
result = gtk_selection_model_set_selection (model, selected, mask);
gtk_bitset_unref (selected);
gtk_bitset_unref (mask);
return result;
}
static gboolean
gtk_selection_model_default_select_range (GtkSelectionModel *model,
guint position,
guint n_items,
gboolean unselect_rest)
{
GtkBitset *selected;
GtkBitset *mask;
gboolean result;
selected = gtk_bitset_new_empty ();
gtk_bitset_add_range (selected, position, n_items);
if (unselect_rest)
{
mask = gtk_bitset_new_empty ();
gtk_bitset_add_range (mask, 0, g_list_model_get_n_items (G_LIST_MODEL (model)));
}
else
{
mask = gtk_bitset_ref (selected);
}
result = gtk_selection_model_set_selection (model, selected, mask);
gtk_bitset_unref (selected);
gtk_bitset_unref (mask);
return result;
}
static gboolean
gtk_selection_model_default_unselect_range (GtkSelectionModel *model,
guint position,
guint n_items)
{
GtkBitset *selected;
GtkBitset *mask;
gboolean result;
selected = gtk_bitset_new_empty ();
mask = gtk_bitset_new_empty ();
gtk_bitset_add_range (mask, position, n_items);
result = gtk_selection_model_set_selection (model, selected, mask);
gtk_bitset_unref (selected);
gtk_bitset_unref (mask);
return result;
}
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 gboolean
gtk_selection_model_default_set_selection (GtkSelectionModel *model,
GtkBitset *selected,
GtkBitset *mask)
{
return FALSE;
}
static void
gtk_selection_model_default_init (GtkSelectionModelInterface *iface)
{
iface->is_selected = gtk_selection_model_default_is_selected;
iface->get_selection_in_range = gtk_selection_model_default_get_selection_in_range;
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->set_selection = gtk_selection_model_default_set_selection;
/**
* 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_get_selection:
* @model: a #GtkSelectionModel
*
* Gets the set containing all currently selected items in the model.
*
* This function may be slow, so if you are only interested in single item,
* consider using gtk_selection_model_is_selected() or if you are only
* interested in a few consider gtk_selection_model_get_selection_in_range().
*
* Returns: (transfer full): a #GtkBitset containing all the values currently
* selected in @model. If no items are selected, the bitset is empty.
* The bitset must not be modified.
**/
GtkBitset *
gtk_selection_model_get_selection (GtkSelectionModel *model)
{
g_return_val_if_fail (GTK_IS_SELECTION_MODEL (model), gtk_bitset_new_empty ());
return gtk_selection_model_get_selection_in_range (model, 0, g_list_model_get_n_items (G_LIST_MODEL (model)));
}
/**
* gtk_selection_model_get_selection_in_range:
* @model: a #GtkSelectionModel
* @position: start of the queired range
* @n_items: number of items in the queried range
*
* Gets a set containing a set where the values in the range `[position,
* position + n_items)` match the selected state of the items in that range.
* All values outside that range are undefined.
*
* This function is an optimization for gtk_selection_model_get_selection() when
* you are only interested in part of the model's selected state. A common use
* case is in response to the #GtkSelectionModel::selection-changed signal.
*
* Returns: A #GtkBitset that matches the selection state for the given state
* with all other values being undefined.
* The bitset must not be modified.
**/
GtkBitset *
gtk_selection_model_get_selection_in_range (GtkSelectionModel *model,
guint position,
guint n_items)
{
GtkSelectionModelInterface *iface;
g_return_val_if_fail (GTK_IS_SELECTION_MODEL (model), gtk_bitset_new_empty ());
if (n_items == 0)
return gtk_bitset_new_empty ();
iface = GTK_SELECTION_MODEL_GET_IFACE (model);
return iface->get_selection_in_range (model, position, n_items);
}
/**
* 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.
*
* Returns: %TRUE if this action was supported and no fallback should be
* tried. This does not mean the item was selected.
*/
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), FALSE);
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.
*
* Returns: %TRUE if this action was supported and no fallback should be
* tried. This does not mean the item was unselected.
*/
gboolean
gtk_selection_model_unselect_item (GtkSelectionModel *model,
guint position)
{
GtkSelectionModelInterface *iface;
g_return_val_if_fail (GTK_IS_SELECTION_MODEL (model), FALSE);
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.
*
* Returns: %TRUE if this action was supported and no fallback should be
* tried. This does not mean the range was selected.
*/
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), FALSE);
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.
*
* Returns: %TRUE if this action was supported and no fallback should be
* tried. This does not mean the range was unselected.
*/
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), FALSE);
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.
*
* Returns: %TRUE if this action was supported and no fallback should be
* tried. This does not mean that all items are now selected.
*/
gboolean
gtk_selection_model_select_all (GtkSelectionModel *model)
{
GtkSelectionModelInterface *iface;
g_return_val_if_fail (GTK_IS_SELECTION_MODEL (model), FALSE);
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.
*
* Returns: %TRUE if this action was supported and no fallback should be
* tried. This does not mean that all items are now unselected.
*/
gboolean
gtk_selection_model_unselect_all (GtkSelectionModel *model)
{
GtkSelectionModelInterface *iface;
g_return_val_if_fail (GTK_IS_SELECTION_MODEL (model), FALSE);
iface = GTK_SELECTION_MODEL_GET_IFACE (model);
return iface->unselect_all (model);
}
/**
* gtk_selection_model_set_selection:
* @model: a #GtkSelectionModel
* @selected: bitmask specifying if items should be selected or
* unselected
* @mask: bitmask specifying which items should be updated
*
* This is the most advanced selection updating method that allows
* the most fine-grained control over selection changes.
* If you can, you should try the simpler versions, as implementations
* are more likely to implement support for those.
*
* Requests that the selection state of all positions set in @mask be
* updated to the respective value in the @selected bitmask.
*
* In pseudocode, it would look something like this:
*
* |[<!-- language="C" -->
* for (i = 0; i < n_items; i++)
* {
* // don't change values not in the mask
* if (!gtk_bitset_contains (mask, i))
* continue;
*
* if (gtk_bitset_contains (selected, i))
* select_item (i);
* else
* unselect_item (i);
* }
*
* gtk_selection_model_selection_changed (model, first_changed_item, n_changed_items);
* ]|
*
* @mask and @selected must not be modified. They may refer to the same bitset,
* which would mean that every item in the set should be selected.
*
* Returns: %TRUE if this action was supported and no fallback should be
* tried. This does not mean that all items were updated according
* to the inputs.
**/
gboolean
gtk_selection_model_set_selection (GtkSelectionModel *model,
GtkBitset *selected,
GtkBitset *mask)
{
GtkSelectionModelInterface *iface;
g_return_val_if_fail (GTK_IS_SELECTION_MODEL (model), FALSE);
g_return_val_if_fail (selected != NULL, FALSE);
g_return_val_if_fail (mask != NULL, FALSE);
iface = GTK_SELECTION_MODEL_GET_IFACE (model);
return iface->set_selection (model, selected, mask);
}
/**
* 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
* #GtkSelectionModel::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);
}