[glibmm] Add Gio::AppInfoMonitor

[Kjell Ahlstedt <kjellahl src gnome org>]

commit 2fe9dbd84c7d5fc7acd9381c5599d8ba85d9446a
Author: Kjell Ahlstedt <kjellahlstedt gmail com>
Date:   Wed Feb 16 13:33:48 2022 +0100

    Add Gio::AppInfoMonitor
    
    Fixes #97

 gio/giomm.h                |  1 +
 gio/giomm/meson.build      |  3 +-
 gio/src/appinfomonitor.ccg | 22 ++++++++++++++
 gio/src/appinfomonitor.hg  | 72 ++++++++++++++++++++++++++++++++++++++++++++++
 gio/src/filelist.am        |  3 +-
 tools/m4/convert_gio.m4    |  1 +
 6 files changed, 100 insertions(+), 2 deletions(-)
---
diff --git a/gio/giomm.h b/gio/giomm.h
index 007cb27e..fe33c51e 100644
--- a/gio/giomm.h
+++ b/gio/giomm.h
@@ -25,6 +25,7 @@
 #include <giomm/actiongroup.h>
 #include <giomm/actionmap.h>
 #include <giomm/appinfo.h>
+#include <giomm/appinfomonitor.h>
 #include <giomm/applaunchcontext.h>
 #include <giomm/application.h>
 #include <giomm/applicationcommandline.h>
diff --git a/gio/giomm/meson.build b/gio/giomm/meson.build
index fc508246..faaeb9b5 100644
--- a/gio/giomm/meson.build
+++ b/gio/giomm/meson.build
@@ -29,8 +29,9 @@ giomm_any_hg_ccg_basenames = [
   'action',
   'actiongroup',
   'actionmap',
-  'applaunchcontext',
   'appinfo',
+  'appinfomonitor',
+  'applaunchcontext',
   'application',
   'applicationcommandline',
   'asyncinitable',
diff --git a/gio/src/appinfomonitor.ccg b/gio/src/appinfomonitor.ccg
new file mode 100644
index 00000000..f6042447
--- /dev/null
+++ b/gio/src/appinfomonitor.ccg
@@ -0,0 +1,22 @@
+/* Copyright (C) 2022 The giomm Development Team
+ *
+ * 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/>.
+ */
+
+#include <gio/gio.h>
+
+namespace Gio
+{
+
+} // namespace Gio
diff --git a/gio/src/appinfomonitor.hg b/gio/src/appinfomonitor.hg
new file mode 100644
index 00000000..0f6fcf38
--- /dev/null
+++ b/gio/src/appinfomonitor.hg
@@ -0,0 +1,72 @@
+/* Copyright (C) 2022 The giomm Development Team
+ *
+ * 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/>.
+ */
+
+_CONFIGINCLUDE(giommconfig.h)
+
+#include <glibmm/object.h>
+
+_DEFS(giomm,gio)
+_PINCLUDE(glibmm/private/object_p.h)
+
+namespace Gio
+{
+
+/** Monitor application information for changes.
+ *
+ * %Gio::AppInfoMonitor is a very simple object used for monitoring the app
+ * info database for changes (ie: newly installed or removed
+ * applications).
+ *
+ * Call get() to get a %Gio::AppInfoMonitor and connect to signal_changed().
+ *
+ * In the usual case, applications should try to make note of the change
+ * (doing things like invalidating caches) but not act on it. In
+ * particular, applications should avoid making calls to Gio::AppInfo APIs
+ * in response to the change signal, deferring these until the time that
+ * the data is actually required. The exception to this case is when
+ * application information is actually being displayed on the screen
+ * (eg: during a search or when the list of all applications is shown).
+ * The reason for this is that changes to the list of installed
+ * applications often come in groups (like during system updates) and
+ * rescanning the list on every change is pointless and expensive.
+ *
+ * @newin{2,72}
+ */
+class GIOMM_API AppInfoMonitor : public Glib::Object
+{
+  _CLASS_GOBJECT(AppInfoMonitor, GAppInfoMonitor, G_APP_INFO_MONITOR, Glib::Object, GObject, , , GIOMM_API)
+
+public:
+  /** Gets the %AppInfoMonitor for the current thread-default main context.
+   *
+   * The %AppInfoMonitor will emit a "changed" signal in the
+   * thread-default main context whenever the list of installed
+   * applications (as reported by Gio::AppInfo::get_all()) may have changed.
+   *
+   * You must only drop the last reference on the return value from under
+   * the same main context as you created it.
+   *
+   * @newin{2,72}
+   *
+   * @return A reference to a %Gio::AppInfoMonitor.
+   */
+  _WRAP_METHOD(static Glib::RefPtr<AppInfoMonitor> get(), g_app_info_monitor_get, newin "2,72")
+
+  // no_default_handler because the wrapped C signal has no default handler.
+  _WRAP_SIGNAL(void changed(), "changed", no_default_handler, newin "2,72")
+};
+
+} // namespace Gio
diff --git a/gio/src/filelist.am b/gio/src/filelist.am
index 38f92d85..8f0f297f 100644
--- a/gio/src/filelist.am
+++ b/gio/src/filelist.am
@@ -14,8 +14,9 @@ giomm_files_any_hg =                  \
        action.hg                       \
        actiongroup.hg                  \
        actionmap.hg                    \
-       applaunchcontext.hg             \
        appinfo.hg                      \
+       appinfomonitor.hg                       \
+       applaunchcontext.hg             \
        application.hg                  \
        applicationcommandline.hg       \
        asyncinitable.hg                \
diff --git a/tools/m4/convert_gio.m4 b/tools/m4/convert_gio.m4
index a8498630..2a5ca578 100644
--- a/tools/m4/convert_gio.m4
+++ b/tools/m4/convert_gio.m4
@@ -93,6 +93,7 @@ _CONVERSION(`const Glib::RefPtr<ActionGroup>&',`GActionGroup*',__CONVERT_REFPTR_
 
 # AppInfo
 _CONVERSION(`GAppInfo*',`Glib::RefPtr<AppInfo>',`Glib::wrap($3)')
+_CONVERSION(`GAppInfoMonitor*',`Glib::RefPtr<AppInfoMonitor>',`Glib::wrap($3)')
 _CONVERSION(`const Glib::RefPtr<AppLaunchContext>&',`GAppLaunchContext*',__CONVERT_REFPTR_TO_P)
 _CONVERSION(`GAppLaunchContext*',`const Glib::RefPtr<AppLaunchContext>&',Glib::wrap($3))
 _CONVERSION(`const Glib::RefPtr<AppInfo>&',`GAppInfo*',__CONVERT_REFPTR_TO_P)