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selectionmodel: Change prototype of query_range()

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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.
This commit is contained in:
Benjamin Otte 2019-02-11 04:57:46 +01:00
parent cd37b872ca
commit 1f56f5c2e9
4 changed files with 86 additions and 40 deletions
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54
gtk/gtkselectionmodel.c
View File

@ -120,13 +120,25 @@ 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
static void
gtk_selection_model_default_query_range (GtkSelectionModel *model,
guint *position,
guint *n_items)
guint position,
guint *start_range,
guint *n_items,
gboolean *selected)
{
*n_items = 1;
return gtk_selection_model_is_selected (model, *position);
*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
@ -266,27 +278,41 @@ gtk_selection_model_unselect_all (GtkSelectionModel *model)
/**
* gtk_selection_model_query_range:
* @model: a #GtkSelectionModel
* @position: (inout): specifies the position on input, and the first element of the range on output
* @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.
* The returned range is guaranteed to include the passed-in position.
* The selection status is returned from this function.
*
* Returns: %TRUE if the elements in the returned range are selected, %FALSE otherwise
* 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.
*/
gboolean
void
gtk_selection_model_query_range (GtkSelectionModel *model,
guint *position,
guint *n_items)
guint position,
guint *start_range,
guint *n_items,
gboolean *selected)
{
GtkSelectionModelInterface *iface;
g_return_val_if_fail (GTK_IS_SELECTION_MODEL (model), FALSE);
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, n_items);
return iface->query_range (model, position, start_range, n_items, selected);
}
void

16
gtk/gtkselectionmodel.h
View File

@ -79,9 +79,11 @@ struct _GtkSelectionModelInterface
guint n_items);
gboolean (* select_all) (GtkSelectionModel *model);
gboolean (* unselect_all) (GtkSelectionModel *model);
gboolean (* query_range) (GtkSelectionModel *model,
guint *position,
guint *n_items);
void (* query_range) (GtkSelectionModel *model,
guint position,
guint *start_range,
guint *n_items,
gboolean *selected);
};
GDK_AVAILABLE_IN_ALL
@ -110,9 +112,11 @@ GDK_AVAILABLE_IN_ALL
gboolean gtk_selection_model_unselect_all (GtkSelectionModel *model);
GDK_AVAILABLE_IN_ALL
gboolean gtk_selection_model_query_range (GtkSelectionModel *model,
guint *position,
guint *n_items);
void gtk_selection_model_query_range (GtkSelectionModel *model,
guint position,
guint *start_range,
guint *n_items,
gboolean *selected);
/* for implementations only */
GDK_AVAILABLE_IN_ALL

47
gtk/gtksingleselection.c
View File

@ -133,36 +133,47 @@ gtk_single_selection_unselect_item (GtkSelectionModel *model,
return TRUE;
}
static gboolean
static void
gtk_single_selection_query_range (GtkSelectionModel *model,
guint *position,
guint *n_items)
guint position,
guint *start_range,
guint *n_range,
gboolean *selected)
{
GtkSingleSelection *self = GTK_SINGLE_SELECTION (model);
guint n_items;
if (self->selected == GTK_INVALID_LIST_POSITION)
n_items = g_list_model_get_n_items (self->model);
if (position >= n_items)
{
*position = 0;
*n_items = g_list_model_get_n_items (self->model);
return FALSE;
*start_range = position;
*n_range = 0;
*selected = FALSE;
}
else if (*position < self->selected)
else if (self->selected == GTK_INVALID_LIST_POSITION)
{
*position = 0;
*n_items = self->selected;
return FALSE;
*start_range = 0;
*n_range = n_items;
*selected = FALSE;
}
else if (*position > self->selected)
else if (position < self->selected)
{
*position = self->selected + 1;
*n_items = g_list_model_get_n_items (self->model) - *position;
return FALSE;
*start_range = 0;
*n_range = self->selected;
*selected = FALSE;
}
else if (position > self->selected)
{
*start_range = self->selected + 1;
*n_range = n_items - *start_range;
*selected = FALSE;
}
else
{
*position = self->selected;
*n_items = 1;
return TRUE;
*start_range = self->selected;
*n_range = 1;
*selected = TRUE;
}
}

9
testsuite/gtk/singleselection.c
View File

@ -495,14 +495,19 @@ check_query_range (GtkSelectionModel *selection)
/* check that range always contains position, and has uniform selection */
for (i = 0; i < g_list_model_get_n_items (G_LIST_MODEL (selection)); i++)
{
position = i;
selected = gtk_selection_model_query_range (selection, &position, &n_items);
gtk_selection_model_query_range (selection, i, &position, &n_items, &selected);
g_assert_cmpint (position, <=, i);
g_assert_cmpint (i, <, position + n_items);
for (j = position; j < position + n_items; j++)
g_assert_true (selected == gtk_selection_model_is_selected (selection, j));
}
/* check that out-of-range returns the correct invalid values */
i = MIN (i, g_random_int ());
gtk_selection_model_query_range (selection, i, &position, &n_items, &selected);
g_assert_cmpint (position, ==, i);
g_assert_cmpint (n_items, ==, 0);
g_assert_true (!selected);
}
static void