filter: Add GtkStringFilter

Users provide a search filter and an expression that evaluates the items
to a string and then the filter goes and matches those strings to the
search term.

docs/reference/gtk/gtk4-docs.xml

@@ -53,6 +53,7 @@
       <section>
         <xi:include href="xml/gtkfilter.xml" />
         <xi:include href="xml/gtkcustomfilter.xml" />
+        <xi:include href="xml/gtkstringfilter.xml" />
       </section>
       <xi:include href="xml/gtkflattenlistmodel.xml" />
       <xi:include href="xml/gtkmaplistmodel.xml" />

docs/reference/gtk/gtk4-sections.txt

@@ -7101,3 +7101,21 @@ GTK_TYPE_EXPRESSION
 <SUBSECTION Private>
 gtk_expression_get_type
 </SECTION>
+
+<SECTION>
+<FILE>gtkstringfilter</FILE>
+GtkStringFilter
+GtkStringFilterMatchMode
+gtk_string_filter_new
+gtk_string_filter_get_search
+gtk_string_filter_set_search
+gtk_string_filter_get_expression
+gtk_string_filter_set_expression
+gtk_string_filter_get_ignore_case
+gtk_string_filter_set_ignore_case
+gtk_string_filter_get_match_mode
+gtk_string_filter_set_match_mode
+
+<SUBSECTION Private>
+gtk_string_filter_get_type
+</SECTION>

docs/reference/gtk/gtk4.types.in

@@ -189,6 +189,7 @@ gtk_stack_page_get_type
 gtk_stack_sidebar_get_type
 gtk_stack_switcher_get_type
 gtk_statusbar_get_type
+gtk_string_filter_get_type
 gtk_switch_get_type
 gtk_level_bar_get_type
 gtk_style_context_get_type

gtk/gtk.h

@@ -222,6 +222,7 @@
 #include <gtk/gtkstack.h>
 #include <gtk/gtkstackswitcher.h>
 #include <gtk/gtkstatusbar.h>
+#include <gtk/gtkstringfilter.h>
 #include <gtk/gtkstylecontext.h>
 #include <gtk/gtkstyleprovider.h>
 #include <gtk/gtkswitch.h>

gtk/gtkstringfilter.c

@@ -0,0 +1,532 @@
+/*
+ * Copyright © 2019 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 "gtkstringfilter.h"
+
+#include "gtkintl.h"
+#include "gtktypebuiltins.h"
+
+/**
+ * SECTION:gtkstringfilter
+ * @Title: GtkStringFilter
+ * @Short_description: Filtering by string
+ *
+ * GtkStringFilter determines whether to include items by looking
+ * at strings and comparing them to a fixed search term. The strings
+ * are obtained from the items by evaluating a #GtkExpression.
+ *
+ * GtkStringFilter has several different modes of comparison - it
+ * can match the whole string, just a prefix, or any substring.
+ */
+
+struct _GtkStringFilter
+{
+  GtkFilter parent_instance;
+
+  char *search;
+  char *search_prepared;
+
+  gboolean ignore_case;
+  GtkStringFilterMatchMode match_mode;
+
+  GtkExpression *expression;
+};
+
+enum {
+  PROP_0,
+  PROP_EXPRESSION,
+  PROP_IGNORE_CASE,
+  PROP_MATCH_MODE,
+  PROP_SEARCH,
+  NUM_PROPERTIES
+};
+
+G_DEFINE_TYPE (GtkStringFilter, gtk_string_filter, GTK_TYPE_FILTER)
+
+static GParamSpec *properties[NUM_PROPERTIES] = { NULL, };
+
+static char *
+gtk_string_filter_prepare (GtkStringFilter *self,
+                           const char      *s)
+{
+  char *tmp;
+  char *result;
+
+  if (s == NULL || s[0] == '\0')
+    return NULL;
+
+  tmp = g_utf8_normalize (s, -1, G_NORMALIZE_ALL);
+
+  if (!self->ignore_case)
+    return tmp;
+
+  result = g_utf8_casefold (tmp, -1);
+  g_free (tmp);
+
+  return result;
+}
+
+/* This is necessary because code just looks at self->search otherwise
+ * and that can be the empty string...
+ */
+static gboolean
+gtk_string_filter_has_search (GtkStringFilter *self)
+{
+  return self->search_prepared != NULL;
+}
+
+static gboolean
+gtk_string_filter_match (GtkFilter *filter,
+                         gpointer   item)
+{
+  GtkStringFilter *self = GTK_STRING_FILTER (filter);
+  GValue value = G_VALUE_INIT;
+  char *prepared;
+  const char *s;
+  gboolean result;
+
+  if (!gtk_string_filter_has_search (self))
+    return TRUE;
+
+  if (self->expression == NULL ||
+      !gtk_expression_evaluate (self->expression, item, &value))
+    return FALSE;
+  s = g_value_get_string (&value);
+  if (s == NULL)
+    return FALSE;
+  prepared = gtk_string_filter_prepare (self, s);
+
+  switch (self->match_mode)
+    {
+    case GTK_STRING_FILTER_MATCH_MODE_EXACT:
+      result = strcmp (prepared, self->search_prepared) == 0;
+      break;
+    case GTK_STRING_FILTER_MATCH_MODE_SUBSTRING:
+      result = strstr (prepared, self->search_prepared) != NULL;
+      break;
+    case GTK_STRING_FILTER_MATCH_MODE_PREFIX:
+      result = g_str_has_prefix (prepared, self->search_prepared);
+      break;
+    default:
+      g_assert_not_reached ();
+    }
+
+#if 0
+  g_print ("%s (%s) %s %s (%s)\n", s, prepared, result ? "==" : "!=", self->search, self->search_prepared);
+#endif
+
+  g_free (prepared);
+  g_value_unset (&value);
+
+  return result;
+}
+
+static GtkFilterMatch
+gtk_string_filter_get_strictness (GtkFilter *filter)
+{
+  GtkStringFilter *self = GTK_STRING_FILTER (filter);
+
+  if (!gtk_string_filter_has_search (self))
+    return GTK_FILTER_MATCH_ALL;
+
+  if (self->expression == NULL)
+    return GTK_FILTER_MATCH_NONE;
+
+  return GTK_FILTER_MATCH_SOME;
+}
+
+static void
+gtk_string_filter_set_property (GObject      *object,
+                                guint         prop_id,
+                                const GValue *value,
+                                GParamSpec   *pspec)
+{
+  GtkStringFilter *self = GTK_STRING_FILTER (object);
+
+  switch (prop_id)
+    {
+    case PROP_EXPRESSION:
+      gtk_string_filter_set_expression (self, g_value_get_boxed (value));
+      break;
+
+    case PROP_IGNORE_CASE:
+      gtk_string_filter_set_ignore_case (self, g_value_get_boolean (value));
+      break;
+
+    case PROP_MATCH_MODE:
+      gtk_string_filter_set_match_mode (self, g_value_get_enum (value));
+      break;
+
+    case PROP_SEARCH:
+      gtk_string_filter_set_search (self, g_value_get_string (value));
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+    }
+}
+
+static void 
+gtk_string_filter_get_property (GObject     *object,
+                                guint        prop_id,
+                                GValue      *value,
+                                GParamSpec  *pspec)
+{
+  GtkStringFilter *self = GTK_STRING_FILTER (object);
+
+  switch (prop_id)
+    {
+    case PROP_EXPRESSION:
+      g_value_set_boxed (value, self->expression);
+      break;
+
+    case PROP_IGNORE_CASE:
+      g_value_set_boolean (value, self->ignore_case);
+      break;
+
+    case PROP_MATCH_MODE:
+      g_value_set_enum (value, self->match_mode);
+      break;
+
+    case PROP_SEARCH:
+      g_value_set_string (value, self->search);
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+    }
+}
+
+static void
+gtk_string_filter_dispose (GObject *object)
+{
+  GtkStringFilter *self = GTK_STRING_FILTER (object);
+
+  g_clear_pointer (&self->search, g_free);
+  g_clear_pointer (&self->search_prepared, g_free);
+  g_clear_pointer (&self->expression, gtk_expression_unref);
+
+  G_OBJECT_CLASS (gtk_string_filter_parent_class)->dispose (object);
+}
+
+static void
+gtk_string_filter_class_init (GtkStringFilterClass *class)
+{
+  GtkFilterClass *filter_class = GTK_FILTER_CLASS (class);
+  GObjectClass *object_class = G_OBJECT_CLASS (class);
+
+  filter_class->match = gtk_string_filter_match;
+  filter_class->get_strictness = gtk_string_filter_get_strictness;
+
+  object_class->get_property = gtk_string_filter_get_property;
+  object_class->set_property = gtk_string_filter_set_property;
+  object_class->dispose = gtk_string_filter_dispose;
+
+  /**
+   * GtkStringFilter:expression:
+   *
+   * The expression to evalute on item to get a string to compare with
+   */
+  properties[PROP_EXPRESSION] =
+      g_param_spec_boxed ("expression",
+                          P_("Expression"),
+                          P_("Expression to compare with"),
+                          GTK_TYPE_EXPRESSION,
+                          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS | G_PARAM_EXPLICIT_NOTIFY);
+
+  /**
+   * GtkStringFilter:ignore-case:
+   *
+   * If matching is case sensitive
+   */
+  properties[PROP_IGNORE_CASE] =
+      g_param_spec_boolean ("ignore-case",
+                            P_("Ignore case"),
+                            P_("If matching is case sensitive"),
+                            TRUE,
+                            G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS | G_PARAM_EXPLICIT_NOTIFY);
+
+  /**
+   * GtkStringFilter:match-mode:
+   *
+   * If exact matches are necessary or if substrings are allowed
+   */
+  properties[PROP_MATCH_MODE] =
+      g_param_spec_enum ("match-mode",
+                         P_("Match mode"),
+                         P_("If exact matches are necessary or if substrings are allowed"),
+                         GTK_TYPE_STRING_FILTER_MATCH_MODE,
+                         GTK_STRING_FILTER_MATCH_MODE_SUBSTRING,
+                         G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS | G_PARAM_EXPLICIT_NOTIFY);
+
+  /**
+   * GtkStringFilter:search:
+   *
+   * The search term
+   */
+  properties[PROP_SEARCH] =
+      g_param_spec_string ("search",
+                           P_("Search"),
+                           P_("The search term"),
+                           NULL,
+                           G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS | G_PARAM_EXPLICIT_NOTIFY);
+
+  g_object_class_install_properties (object_class, NUM_PROPERTIES, properties);
+
+}
+
+static void
+gtk_string_filter_init (GtkStringFilter *self)
+{
+  self->ignore_case = TRUE;
+  self->match_mode = GTK_STRING_FILTER_MATCH_MODE_SUBSTRING;
+}
+
+/**
+ * gtk_string_filter_new:
+ *
+ * Creates a new string filter.
+ *
+ * You will want to set up the filter by providing a string to search for
+ * and by providing a property to look up on the item.
+ *
+ * Returns: a new #GtkStringFilter
+ **/
+GtkFilter *
+gtk_string_filter_new (void)
+{
+  return g_object_new (GTK_TYPE_STRING_FILTER, NULL);
+}
+
+/**
+ * gtk_string_filter_get_search:
+ * @self: a #GtkStringFilter
+ *
+ * Gets the search string set via gtk_string_filter_set_search().
+ *
+ * Returns: (allow-none) (transfer none): The search string
+ **/
+const char *
+gtk_string_filter_get_search (GtkStringFilter *self)
+{
+  g_return_val_if_fail (GTK_IS_STRING_FILTER (self), NULL);
+
+  return self->search;
+}
+
+/**
+ * gtk_string_filter_set_search:
+ * @self: a #GtkStringFilter
+ * @search: (transfer none) (nullable): The string to search for
+ *     or %NULL to clear the search
+ *
+ * Sets the string to search for.
+ **/
+void
+gtk_string_filter_set_search (GtkStringFilter *self,
+                              const char      *search)
+{
+  GtkFilterChange change;
+
+  g_return_if_fail (GTK_IS_STRING_FILTER (self));
+
+  if (g_strcmp0 (self->search, search) == 0)
+    return;
+
+  if (search == NULL || search[0] == 0)
+    change = GTK_FILTER_CHANGE_LESS_STRICT;
+  else if (!gtk_string_filter_has_search (self))
+    change = GTK_FILTER_CHANGE_MORE_STRICT;
+  else if (g_str_has_prefix (search, self->search))
+    change = GTK_FILTER_CHANGE_MORE_STRICT;
+  else if (g_str_has_prefix (self->search, search))
+    change = GTK_FILTER_CHANGE_LESS_STRICT;
+  else
+    change = GTK_FILTER_CHANGE_DIFFERENT;
+
+  g_free (self->search);
+  g_free (self->search_prepared);
+
+  self->search = g_strdup (search);
+  self->search_prepared = gtk_string_filter_prepare (self, search);
+
+  gtk_filter_changed (GTK_FILTER (self), change);
+
+  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_SEARCH]);
+}
+
+/**
+ * gtk_string_filter_get_expression:
+ * @self: a #GtkStringFilter
+ *
+ * Gets the expression that the string filter uses to
+ * obtain strings from items.
+ *
+ * Returns: a #GtkExpression
+ */
+GtkExpression *
+gtk_string_filter_get_expression (GtkStringFilter *self)
+{
+  g_return_val_if_fail (GTK_IS_STRING_FILTER (self), NULL);
+
+  return self->expression;
+}
+
+/**
+ * gtk_string_filter_set_expression:
+ * @self: a #GtkStringFilter
+ * @expression: a #GtkExpression
+ *
+ * Sets the expression that the string filter uses to
+ * obtain strings from items. The expression must have
+ * a value type of #G_TYPE_STRING.
+ */
+void
+gtk_string_filter_set_expression (GtkStringFilter *self,
+                                  GtkExpression   *expression)
+{
+  g_return_if_fail (GTK_IS_STRING_FILTER (self));
+  g_return_if_fail (expression == NULL || gtk_expression_get_value_type (expression) == G_TYPE_STRING);
+
+  if (self->expression == expression)
+    return;
+
+  g_clear_pointer (&self->expression, gtk_expression_unref);
+  self->expression = gtk_expression_ref (expression);
+
+  if (gtk_string_filter_has_search (self))
+    gtk_filter_changed (GTK_FILTER (self), GTK_FILTER_CHANGE_DIFFERENT);
+
+  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_EXPRESSION]);
+}
+
+/**
+ * gtk_string_filter_get_ignore_case:
+ * @self: a #GtkStringFilter
+ *
+ * Returns whether the filter ignores case differences.
+ *
+ * Returns: %TRUE if the filter ignores case
+ */
+gboolean
+gtk_string_filter_get_ignore_case (GtkStringFilter *self)
+{
+  g_return_val_if_fail (GTK_IS_STRING_FILTER (self), TRUE);
+
+  return self->ignore_case;
+}
+
+/**
+ * gtk_string_filter_set_ignore_case:
+ * @self: a #GtkStringFilter
+ * @ignore_case: %TRUE to ignore case
+ *
+ * Sets whether the filter ignores case differences.
+ */
+void
+gtk_string_filter_set_ignore_case (GtkStringFilter *self,
+                                   gboolean         ignore_case)
+{
+  g_return_if_fail (GTK_IS_STRING_FILTER (self));
+
+  if (self->ignore_case == ignore_case)
+    return;
+
+  self->ignore_case = ignore_case;
+
+  if (self->search)
+    {
+      g_free (self->search_prepared);
+      self->search_prepared = gtk_string_filter_prepare (self, self->search);
+      gtk_filter_changed (GTK_FILTER (self), ignore_case ? GTK_FILTER_CHANGE_LESS_STRICT : GTK_FILTER_CHANGE_MORE_STRICT);
+    }
+
+  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_IGNORE_CASE]);
+}
+
+/**
+ * gtk_string_filter_get_match_mode:
+ * @self: a #GtkStringFilter
+ *
+ * Returns the match mode that the filter is using.
+ *
+ * Returns: the match mode of the filter
+ */
+GtkStringFilterMatchMode
+gtk_string_filter_get_match_mode (GtkStringFilter *self)
+{
+  g_return_val_if_fail (GTK_IS_STRING_FILTER (self), GTK_STRING_FILTER_MATCH_MODE_EXACT);
+
+  return self->match_mode;
+}
+
+/**
+ * gtk_string_filter_set_match_mode:
+ * @self: a #GtkStringFilter
+ * @mode: the new match mode
+ *
+ * Sets the match mode fot the filter.
+ */
+void
+gtk_string_filter_set_match_mode (GtkStringFilter *self,
+                                  GtkStringFilterMatchMode mode)
+{
+  GtkStringFilterMatchMode old_mode;
+
+  g_return_if_fail (GTK_IS_STRING_FILTER (self));
+
+  if (self->match_mode == mode)
+    return;
+
+  old_mode = self->match_mode;
+  self->match_mode = mode;
+
+  if (self->search_prepared && self->expression)
+    {
+      switch (old_mode)
+        {
+        case GTK_STRING_FILTER_MATCH_MODE_EXACT:
+          gtk_filter_changed (GTK_FILTER (self), GTK_FILTER_CHANGE_LESS_STRICT);
+          break;
+
+        case GTK_STRING_FILTER_MATCH_MODE_SUBSTRING:
+          gtk_filter_changed (GTK_FILTER (self), GTK_FILTER_CHANGE_MORE_STRICT);
+          break;
+
+        case GTK_STRING_FILTER_MATCH_MODE_PREFIX:
+          if (mode == GTK_STRING_FILTER_MATCH_MODE_SUBSTRING)
+            gtk_filter_changed (GTK_FILTER (self), GTK_FILTER_CHANGE_LESS_STRICT);
+          else
+            gtk_filter_changed (GTK_FILTER (self), GTK_FILTER_CHANGE_MORE_STRICT);
+          break;
+
+        default:
+          g_assert_not_reached ();
+          break;
+        }
+    }
+
+  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_MATCH_MODE]);
+}
+
+                                                                 

gtk/gtkstringfilter.h

@@ -0,0 +1,81 @@
+/*
+ * Copyright © 2019 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>
+ */
+
+#ifndef __GTK_STRING_FILTER_H__
+#define __GTK_STRING_FILTER_H__
+
+#if !defined (__GTK_H_INSIDE__) && !defined (GTK_COMPILATION)
+#error "Only <gtk/gtk.h> can be included directly."
+#endif
+
+#include <gtk/gtkexpression.h>
+#include <gtk/gtkfilter.h>
+
+G_BEGIN_DECLS
+
+/**
+ * GtkStringFilterMatchMode:
+ * @GTK_STRING_FILTER_MATCH_MODE_EXACT: The search string and
+ *     text must match exactly.
+ * @GTK_STRING_FILTER_MATCH_MODE_SUBSTRING: The search string
+ *     must be contained as a substring inside the text.
+ * @GTK_STRING_FILTER_MATCH_MODE_PREFIX: The text must begin
+ *     with the search string.
+ *
+ * Specifies how search strings are matched inside text.
+ */
+typedef enum {
+  GTK_STRING_FILTER_MATCH_MODE_EXACT,
+  GTK_STRING_FILTER_MATCH_MODE_SUBSTRING,
+  GTK_STRING_FILTER_MATCH_MODE_PREFIX
+} GtkStringFilterMatchMode;
+
+#define GTK_TYPE_STRING_FILTER             (gtk_string_filter_get_type ())
+GDK_AVAILABLE_IN_ALL
+G_DECLARE_FINAL_TYPE (GtkStringFilter, gtk_string_filter, GTK, STRING_FILTER, GtkFilter)
+
+GDK_AVAILABLE_IN_ALL
+GtkFilter *             gtk_string_filter_new                   (void);
+
+GDK_AVAILABLE_IN_ALL
+const char *            gtk_string_filter_get_search            (GtkStringFilter        *self);
+GDK_AVAILABLE_IN_ALL
+void                    gtk_string_filter_set_search            (GtkStringFilter        *self,
+                                                                 const char             *search);
+GDK_AVAILABLE_IN_ALL
+GtkExpression *         gtk_string_filter_get_expression        (GtkStringFilter        *self);
+GDK_AVAILABLE_IN_ALL
+void                    gtk_string_filter_set_expression        (GtkStringFilter        *self,
+                                                                 GtkExpression          *expression);
+GDK_AVAILABLE_IN_ALL
+gboolean                gtk_string_filter_get_ignore_case       (GtkStringFilter        *self);
+GDK_AVAILABLE_IN_ALL
+void                    gtk_string_filter_set_ignore_case       (GtkStringFilter        *self,
+                                                                 gboolean                ignore_case);
+GDK_AVAILABLE_IN_ALL
+GtkStringFilterMatchMode gtk_string_filter_get_match_mode   (GtkStringFilter          *self);
+GDK_AVAILABLE_IN_ALL
+void                     gtk_string_filter_set_match_mode   (GtkStringFilter          *self,
+                                                             GtkStringFilterMatchMode  mode);
+
+
+
+G_END_DECLS
+
+#endif /* __GTK_STRING_FILTER_H__ */

gtk/meson.build

@@ -352,6 +352,7 @@ gtk_public_sources = files([
   'gtkstacksidebar.c',
   'gtkstackswitcher.c',
   'gtkstatusbar.c',
+  'gtkstringfilter.c',
   'gtkstylecontext.c',
   'gtkstyleprovider.c',
   'gtkswitch.c',
@@ -596,6 +597,7 @@ gtk_public_headers = files([
   'gtkstacksidebar.h',
   'gtkstackswitcher.h',
   'gtkstatusbar.h',
+  'gtkstringfilter.h',
   'gtkstylecontext.h',
   'gtkstyleprovider.h',
   'gtkswitch.h',