forked from AuroraMiddleware/gtk
1f56f5c2e9
1. Do not make position an inout variable The function is meant to return a range for a given position, not modify a position. So it makes no conceptual sense to use an inout variable. 2. Pass the selected state as an out variable Using a boolean return value - in particular in an interface full of boolean return values - makes the return value intuitively feel like a success/failure return. Using an out variable clarifies the usage. 3. Allow passing every position value Define what happens when position >= list.n_items 4. Clarify the docs about how this function should behave In particular, mention the case from point (3) 5. Add more tests Again, (3) needs testing.
330 lines
12 KiB
C
330 lines
12 KiB
C
/*
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* Copyright © 2018 Benjamin Otte
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library. If not, see <http://www.gnu.org/licenses/>.
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*
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* Authors: Benjamin Otte <otte@gnome.org>
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*/
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#include "config.h"
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#include "gtkselectionmodel.h"
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#include "gtkintl.h"
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#include "gtkmarshalers.h"
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/**
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* SECTION:gtkselectionmodel
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* @Title: GtkSelectionModel
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* @Short_description: An extension of the list model interface that handles selections
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* @See_also: #GListModel, #GtkSingleSelection
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*
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* #GtkSelectionModel is an interface that extends the #GListModel interface by adding
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* support for selections. This support is then used by widgets using list models to add
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* the ability to select and unselect various items.
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*
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* GTK provides default implementations of the mode common selection modes such as
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* #GtkSingleSelection, so you will only need to implement this interface if you want
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* detailed control about how selections should be handled.
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*
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* A #GtkSelectionModel supports a single boolean per row indicating if a row is selected
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* or not. This can be queried via gtk_selection_model_is_selected(). When the selected
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* state of one or more rows changes, the model will emit the
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* GtkSelectionModel::selection-changed signal by calling the
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* gtk_selection_model_selection_changed() function. The positions given in that signal
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* may have their selection state changed, though that is not a requirement.
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* If new items added to the model via the #GListModel::items-changed signal are selected
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* or not is up to the implementation.
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*
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* Additionally, the interface can expose functionality to select and unselect items.
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* If these functions are implemented, GTK's list widgets will allow users to select and
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* unselect items. However, #GtkSelectionModels are free to only implement them
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* partially or not at all. In that case the widgets will not support the unimplemented
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* operations.
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*
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* When selecting or unselecting is supported by a model, the return values of the
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* selection functions do NOT indicate if selection or unselection happened. They are
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* only meant to indicate complete failure, like when this mode of selecting is not
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* supported by the model.
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* Selections may happen asynchronously, so the only reliable way to find out when an
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* item was selected is to listen to the signals that indicate selection.
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*/
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G_DEFINE_INTERFACE (GtkSelectionModel, gtk_selection_model, G_TYPE_LIST_MODEL)
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enum {
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SELECTION_CHANGED,
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LAST_SIGNAL
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};
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static guint signals[LAST_SIGNAL] = { 0 };
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static gboolean
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gtk_selection_model_default_is_selected (GtkSelectionModel *model,
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guint position)
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{
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return FALSE;
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}
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static gboolean
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gtk_selection_model_default_select_item (GtkSelectionModel *model,
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guint position,
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gboolean exclusive)
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{
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return FALSE;
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}
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static gboolean
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gtk_selection_model_default_unselect_item (GtkSelectionModel *model,
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guint position)
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{
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return FALSE;
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}
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static gboolean
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gtk_selection_model_default_select_range (GtkSelectionModel *model,
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guint position,
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guint n_items,
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gboolean exclusive)
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{
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return FALSE;
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}
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static gboolean
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gtk_selection_model_default_unselect_range (GtkSelectionModel *model,
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guint position,
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guint n_items)
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{
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return FALSE;
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}
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static gboolean
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gtk_selection_model_default_select_all (GtkSelectionModel *model)
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{
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return gtk_selection_model_select_range (model, 0, g_list_model_get_n_items (G_LIST_MODEL (model)), FALSE);
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}
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static gboolean
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gtk_selection_model_default_unselect_all (GtkSelectionModel *model)
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{
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return gtk_selection_model_unselect_range (model, 0, g_list_model_get_n_items (G_LIST_MODEL (model)));;
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}
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static void
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gtk_selection_model_default_query_range (GtkSelectionModel *model,
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guint position,
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guint *start_range,
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guint *n_items,
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gboolean *selected)
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{
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*start_range = position;
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if (position >= g_list_model_get_n_items (G_LIST_MODEL (model)))
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{
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*n_items = 0;
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*selected = FALSE;
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}
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else
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{
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*n_items = 1;
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*selected = gtk_selection_model_is_selected (model, position);
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}
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}
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static void
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gtk_selection_model_default_init (GtkSelectionModelInterface *iface)
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{
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iface->is_selected = gtk_selection_model_default_is_selected;
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iface->select_item = gtk_selection_model_default_select_item;
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iface->unselect_item = gtk_selection_model_default_unselect_item;
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iface->select_range = gtk_selection_model_default_select_range;
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iface->unselect_range = gtk_selection_model_default_unselect_range;
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iface->select_all = gtk_selection_model_default_select_all;
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iface->unselect_all = gtk_selection_model_default_unselect_all;
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iface->query_range = gtk_selection_model_default_query_range;
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/**
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* GtkSelectionModel::selection-changed
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* @model: a #GtkSelectionModel
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* @position: The first item that may have changed
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* @n_items: number of items with changes
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*
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* Emitted when the selection state of some of the items in @model changes.
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*
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* Note that this signal does not specify the new selection state of the items,
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* they need to be queried manually.
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* It is also not necessary for a model to change the selection state of any of
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* the items in the selection model, though it would be rather useless to emit
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* such a signal.
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*/
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signals[SELECTION_CHANGED] =
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g_signal_new ("selection-changed",
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GTK_TYPE_SELECTION_MODEL,
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G_SIGNAL_RUN_LAST,
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0,
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NULL, NULL,
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_gtk_marshal_VOID__UINT_UINT,
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G_TYPE_NONE, 2, G_TYPE_UINT, G_TYPE_UINT);
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g_signal_set_va_marshaller (signals[SELECTION_CHANGED],
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GTK_TYPE_SELECTION_MODEL,
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_gtk_marshal_VOID__UINT_UINTv);
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}
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/**
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* gtk_selection_model_is_selected:
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* @model: a #GtkSelectionModel
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* @position: the position of the item to query
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*
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* Checks if the given item is selected.
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*
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* Returns: %TRUE if the item is selected
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**/
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gboolean
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gtk_selection_model_is_selected (GtkSelectionModel *model,
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guint position)
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{
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GtkSelectionModelInterface *iface;
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g_return_val_if_fail (GTK_IS_SELECTION_MODEL (model), 0);
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iface = GTK_SELECTION_MODEL_GET_IFACE (model);
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return iface->is_selected (model, position);
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}
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gboolean
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gtk_selection_model_select_item (GtkSelectionModel *model,
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guint position,
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gboolean exclusive)
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{
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GtkSelectionModelInterface *iface;
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g_return_val_if_fail (GTK_IS_SELECTION_MODEL (model), 0);
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iface = GTK_SELECTION_MODEL_GET_IFACE (model);
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return iface->select_item (model, position, exclusive);
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}
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gboolean
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gtk_selection_model_unselect_item (GtkSelectionModel *model,
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guint position)
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{
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GtkSelectionModelInterface *iface;
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g_return_val_if_fail (GTK_IS_SELECTION_MODEL (model), 0);
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iface = GTK_SELECTION_MODEL_GET_IFACE (model);
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return iface->unselect_item (model, position);
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}
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gboolean
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gtk_selection_model_select_range (GtkSelectionModel *model,
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guint position,
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guint n_items,
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gboolean exclusive)
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{
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GtkSelectionModelInterface *iface;
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g_return_val_if_fail (GTK_IS_SELECTION_MODEL (model), 0);
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iface = GTK_SELECTION_MODEL_GET_IFACE (model);
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return iface->select_range (model, position, n_items, exclusive);
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}
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gboolean
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gtk_selection_model_unselect_range (GtkSelectionModel *model,
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guint position,
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guint n_items)
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{
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GtkSelectionModelInterface *iface;
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g_return_val_if_fail (GTK_IS_SELECTION_MODEL (model), 0);
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iface = GTK_SELECTION_MODEL_GET_IFACE (model);
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return iface->unselect_range (model, position, n_items);
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}
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gboolean
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gtk_selection_model_select_all (GtkSelectionModel *model)
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{
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GtkSelectionModelInterface *iface;
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g_return_val_if_fail (GTK_IS_SELECTION_MODEL (model), 0);
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iface = GTK_SELECTION_MODEL_GET_IFACE (model);
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return iface->select_all (model);
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}
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gboolean
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gtk_selection_model_unselect_all (GtkSelectionModel *model)
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{
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GtkSelectionModelInterface *iface;
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g_return_val_if_fail (GTK_IS_SELECTION_MODEL (model), 0);
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iface = GTK_SELECTION_MODEL_GET_IFACE (model);
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return iface->unselect_all (model);
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}
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/**
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* gtk_selection_model_query_range:
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* @model: a #GtkSelectionModel
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* @position: the position inside the range
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* @start_range: (out): returns the position of the first element of the range
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* @n_items: (out): returns the size of the range
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* @selected: (out): returns whether items in @range are selected
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*
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* This function allows to query the selection status of multiple elements at once.
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* It is passed a position and returns a range of elements of uniform selection status.
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*
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* If @position is greater than the number of items in @model, @n_items is set to 0.
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* Otherwise the returned range is guaranteed to include the passed-in position, so
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* @n_items will be >= 1.
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*
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* Positions directly adjacent to the returned range may have the same selection
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* status as the returned range.
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*
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* This is an optimization function to make iterating over a model faster when few
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* items are selected. However, it is valid behavior for implementations to use a
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* naive implementation that only ever returns a single element.
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*/
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void
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gtk_selection_model_query_range (GtkSelectionModel *model,
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guint position,
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guint *start_range,
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guint *n_items,
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gboolean *selected)
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{
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GtkSelectionModelInterface *iface;
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g_return_if_fail (GTK_IS_SELECTION_MODEL (model));
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g_return_if_fail (start_range != NULL);
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g_return_if_fail (n_items != NULL);
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g_return_if_fail (selected != NULL);
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iface = GTK_SELECTION_MODEL_GET_IFACE (model);
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return iface->query_range (model, position, start_range, n_items, selected);
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}
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void
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gtk_selection_model_selection_changed (GtkSelectionModel *model,
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guint position,
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guint n_items)
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{
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g_return_if_fail (GTK_IS_SELECTION_MODEL (model));
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g_return_if_fail (n_items > 0);
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g_return_if_fail (position + n_items <= g_list_model_get_n_items (G_LIST_MODEL (model)));
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g_signal_emit (model, signals[SELECTION_CHANGED], 0, position, n_items);
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}
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