App: Implement Applications Management (#1241)

This allows us to completely replace libbamf in some specific cases (like system shell elements)

Co-authored-by: Danielle Foré <danielle@elementary.io>

Author: tintou

lib/App.vala

@@ -0,0 +1,179 @@
+/*
+ * Copyright 2021 elementary, Inc. <https://elementary.io>
+ * Copyright 2021 Corentin Noël <tintou@noel.tf>
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+public enum Gala.AppState {
+    STOPPED,
+    STARTING,
+    RUNNING
+}
+
+public class Gala.App : GLib.Object {
+    public string id {
+        get {
+            if (app_info != null) {
+                return app_info.get_id ();
+            } else {
+                return window_id_string;
+            }
+        }
+    }
+
+    public GLib.DesktopAppInfo? app_info { get; construct; }
+
+    public GLib.Icon icon {
+        get {
+            if (app_info != null) {
+                return app_info.get_icon ();
+            }
+
+            if (fallback_icon == null) {
+                fallback_icon = new GLib.ThemedIcon ("application-x-executable");
+            }
+
+            return fallback_icon;
+        }
+    }
+
+    public string name {
+        get {
+            if (app_info != null) {
+                return app_info.get_name ();
+            } else {
+                unowned string? name = null;
+                var window = get_backing_window ();
+                if (window != null) {
+                    name = window.get_wm_class ();
+                }
+
+                return name ?? C_("program", "Unknown");
+            }
+        }
+    }
+
+    public string? description {
+        get {
+            if (app_info != null) {
+                return app_info.get_description ();
+            }
+
+            return null;
+        }
+    }
+
+    public Gala.AppState state { get; private set; default = AppState.STOPPED; }
+
+    private GLib.SList<Meta.Window> windows = new GLib.SList<Meta.Window> ();
+    private uint interesting_windows = 0;
+    private string? window_id_string = null;
+    private GLib.Icon? fallback_icon = null;
+    private int started_on_workspace;
+
+    public static unowned App? new_from_startup_sequence (Meta.StartupSequence sequence) {
+        unowned string? app_id = sequence.get_application_id ();
+        if (app_id == null) {
+            return null;
+        }
+
+        var basename = GLib.Path.get_basename (app_id);
+        unowned var appsys = Gala.AppSystem.get_default ();
+        return appsys.lookup_app (basename);
+    }
+
+    public App (GLib.DesktopAppInfo info) {
+        Object (app_info: info);
+    }
+
+    public App.for_window (Meta.Window window) {
+        window_id_string = "window:%u".printf (window.get_stable_sequence ());
+        add_window (window);
+    }
+
+    public unowned GLib.SList<Meta.Window> get_windows () {
+        return windows;
+    }
+
+    public void add_window (Meta.Window window) {
+        if (windows.find (window) != null) {
+            return;
+        }
+
+        windows.prepend (window);
+        if (!window.is_skip_taskbar ()) {
+            interesting_windows++;
+        }
+
+        sync_running_state ();
+    }
+
+
+    public void remove_window (Meta.Window window) {
+        if (windows.find (window) == null) {
+            return;
+        }
+
+        if (!window.is_skip_taskbar ()) {
+            interesting_windows--;
+        }
+
+        windows.remove (window);
+        sync_running_state ();
+    }
+
+    private void sync_running_state () {
+        if (state != Gala.AppState.STARTING) {
+            unowned var app_sys = Gala.AppSystem.get_default ();
+            if (interesting_windows == 0) {
+                state = Gala.AppState.STOPPED;
+                app_sys.notify_app_state_changed (this);
+            } else {
+                state = Gala.AppState.RUNNING;
+                app_sys.notify_app_state_changed (this);
+            }
+        }
+    }
+
+    public void handle_startup_sequence (Meta.StartupSequence sequence) {
+        bool starting = !sequence.get_completed ();
+
+        if (starting && state == AppState.STOPPED) {
+            state = AppState.STARTING;
+        }
+
+        if (starting) {
+            started_on_workspace = sequence.workspace;
+        } else if (interesting_windows > 0) {
+            state = AppState.RUNNING;
+        } else {
+            state = AppState.STOPPED;
+        }
+
+        unowned var app_sys = Gala.AppSystem.get_default ();
+        app_sys.notify_app_state_changed (this);
+    }
+
+    private Meta.Window? get_backing_window () requires (app_info == null) {
+        return windows.data;
+    }
+
+    public GLib.SList<Posix.pid_t?> get_pids () {
+        var results = new GLib.SList<Posix.pid_t?> ();
+        foreach (unowned var window in windows) {
+            var pid = window.get_pid ();
+            if (pid < 1) {
+                continue;
+            }
+
+            /* Note in the (by far) common case, app will only have one pid, so
+             * we'll hit the first element, so don't worry about O(N^2) here.
+             */
+            if (results.find (pid) == null) {
+                results.prepend (pid);
+            }
+        }
+
+        return results;
+    }
+}

lib/AppCache.vala

@@ -20,16 +20,16 @@ public class Gala.AppCache : GLib.Object {
 
     private const int DEFAULT_TIMEOUT_SECONDS = 3;
 
-    private Gee.HashMap<string, string> startup_wm_class_to_id;
-    private Gee.HashMap<string, GLib.DesktopAppInfo> id_to_app;
+    private GLib.HashTable<unowned string, unowned string> startup_wm_class_to_id;
+    private GLib.HashTable<unowned string, GLib.DesktopAppInfo> id_to_app;
 
     private GLib.AppInfoMonitor app_info_monitor;
 
     private uint queued_update_id = 0;
 
     construct {
-        startup_wm_class_to_id = new Gee.HashMap<string, string> ();
-        id_to_app = new Gee.HashMap<string, GLib.DesktopAppInfo> ();
+        startup_wm_class_to_id = new GLib.HashTable<unowned string, unowned string> (str_hash, str_equal);
+        id_to_app = new GLib.HashTable<unowned string, GLib.DesktopAppInfo> (str_hash, str_equal);
 
         app_info_monitor = GLib.AppInfoMonitor.@get ();
         app_info_monitor.changed.connect (queue_cache_update);
@@ -59,8 +59,8 @@ public class Gala.AppCache : GLib.Object {
 
         new Thread<void> ("rebuild_cache", () => {
             lock (startup_wm_class_to_id) {
-                startup_wm_class_to_id.clear ();
-                id_to_app.clear ();
+                startup_wm_class_to_id.remove_all ();
+                id_to_app.remove_all ();
 
                 var app_infos = GLib.AppInfo.get_all ();
 
@@ -74,7 +74,7 @@ public class Gala.AppCache : GLib.Object {
                         continue;
                     }
 
-                    var old_id = startup_wm_class_to_id[startup_wm_class];
+                    unowned var old_id = startup_wm_class_to_id[startup_wm_class];
                     if (old_id == null || id == startup_wm_class) {
                         startup_wm_class_to_id[startup_wm_class] = id;
                     }
@@ -87,7 +87,7 @@ public class Gala.AppCache : GLib.Object {
         yield;
     }
 
-    public GLib.DesktopAppInfo? lookup_id (string? id) {
+    public unowned GLib.DesktopAppInfo? lookup_id (string? id) {
         if (id == null) {
             return null;
         }
@@ -100,7 +100,7 @@ public class Gala.AppCache : GLib.Object {
             return null;
         }
 
-        var id = startup_wm_class_to_id[wm_class];
+        unowned var id = startup_wm_class_to_id[wm_class];
         if (id == null) {
             return null;
         }

lib/AppSystem.vala

@@ -0,0 +1,111 @@
+/*
+ * Copyright 2021 elementary, Inc. <https://elementary.io>
+ * Copyright 2021 Corentin Noël <tintou@noel.tf>
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+public class Gala.AppSystem : GLib.Object {
+    private static GLib.Once<AppSystem> instance;
+    public static unowned AppSystem get_default () {
+        return instance.once (() => new AppSystem ());
+    }
+
+    private GLib.HashTable<Gala.App, unowned Gala.App> running_apps;
+    private GLib.HashTable<unowned string, Gala.App> id_to_app;
+    private GLib.HashTable<string, string> startup_wm_class_to_id;
+    private Gala.AppCache app_cache;
+
+    construct {
+        id_to_app = new GLib.HashTable<unowned string, Gala.App> (str_hash, str_equal);
+        startup_wm_class_to_id = new GLib.HashTable<string, string> (str_hash, str_equal);
+        running_apps = new GLib.HashTable<Gala.App, unowned Gala.App> (null, null);
+        app_cache = new AppCache ();
+    }
+
+    public unowned Gala.App? lookup_app (string id) {
+        unowned Gala.App? app = id_to_app.lookup (id);
+        if (app != null) {
+            return app;
+        }
+
+        GLib.DesktopAppInfo? info = app_cache.lookup_id (id);
+        if (info == null) {
+            return null;
+        }
+
+        var owned_app = new Gala.App (info);
+        app = owned_app;
+        id_to_app.insert (owned_app.id, (owned) owned_app);
+        return app;
+    }
+
+    public unowned Gala.App? lookup_startup_wmclass (string wmclass) {
+        GLib.DesktopAppInfo? info = app_cache.lookup_startup_wmclass (wmclass);
+        if (info == null) {
+            return null;
+        }
+
+        return lookup_app (info.get_id ());
+    }
+
+    private unowned Gala.App? lookup_heuristic_basename (string name) {
+        /* Vendor prefixes are something that can be preprended to a .desktop
+         * file name.
+         */
+        const string[] VENDOR_PREFIXES = {
+            "gnome-",
+            "fedora-",
+            "mozilla-",
+            "debian-",
+        };
+
+        unowned Gala.App? result = lookup_app (name);
+        if (result != null) {
+            return result;
+        }
+
+        foreach (unowned string prefix in VENDOR_PREFIXES) {
+            result = lookup_app (prefix.concat (name));
+            if (result != null) {
+                return result;
+            }
+        }
+
+        return null;
+    }
+
+    public unowned Gala.App? lookup_desktop_wmclass (string wmclass) {
+        /* First try without changing the case (this handles
+        org.example.Foo.Bar.desktop applications)
+
+        Note that is slightly wrong in that Gtk+ would set
+        the WM_CLASS to Org.example.Foo.Bar, but it also
+        sets the instance part to org.example.Foo.Bar, so we're ok
+        */
+        var desktop_file = wmclass.concat (".desktop");
+        unowned Gala.App? app = lookup_heuristic_basename (desktop_file);
+        if (app != null) {
+            return app;
+        }
+
+        /* This handles "Fedora Eclipse", probably others.
+         * Note _strdelimit is modify-in-place. */
+        desktop_file._delimit (" ", '-');
+
+        desktop_file = desktop_file.ascii_down ().concat (".desktop");
+
+        return lookup_heuristic_basename (desktop_file);
+    }
+
+    public void notify_app_state_changed (Gala.App app) {
+        if (app.state == Gala.AppState.RUNNING) {
+            running_apps.insert (app, app);
+        } else if (app.state == Gala.AppState.STOPPED) {
+            running_apps.remove (app);
+        }
+    }
+
+    public GLib.List<unowned Gala.App> get_running_apps () {
+        return running_apps.get_keys ();
+    }
+}

lib/meson.build

@@ -1,6 +1,8 @@
 gala_lib_sources = files(
     'ActivatableComponent.vala',
+    'App.vala',
     'AppCache.vala',
+    'AppSystem.vala',
     'Constants.vala',
     'DragDropAction.vala',
     'Drawing/BufferSurface.vala',
@@ -48,7 +50,7 @@ pkg.generate(
     name: 'Gala',
     description: 'Library to develop plugins for Gala',
     subdirs: 'gala',
-    requires: [glib_dep, gobject_dep, libmutter_dep],
+    requires: [glib_dep, gobject_dep, gio_dep, gio_unix_dep, libmutter_dep],
     variables: [
         'datarootdir=${prefix}/@0@'.format(get_option('datadir')),
         'pkgdatadir=${datarootdir}/gala'

meson.build

@@ -87,6 +87,7 @@ canberra_dep = dependency('libcanberra')
 glib_dep = dependency('glib-2.0', version: '>= @0@'.format(glib_version_required))
 gobject_dep = dependency('gobject-2.0', version: '>= @0@'.format(glib_version_required))
 gio_dep = dependency('gio-2.0', version: '>= @0@'.format(glib_version_required))
+gio_unix_dep = dependency('gio-unix-2.0', version: '>= @0@'.format(glib_version_required))
 gmodule_dep = dependency('gmodule-2.0')
 gtk_dep = [dependency('gtk+-3.0', version: '>= @0@'.format(gtk_version_required)), dependency('gdk-x11-3.0')]
 gee_dep = dependency('gee-0.8')
@@ -190,7 +191,7 @@ endif
 add_project_arguments(vala_flags, language: 'vala')
 add_project_link_arguments(['-Wl,-rpath,@0@'.format(mutter_typelib_dir)], language: 'c')
 
-gala_base_dep = [canberra_dep, glib_dep, gobject_dep, gio_dep, gmodule_dep, gee_dep, gtk_dep, mutter_dep, granite_dep, gnome_desktop_dep, m_dep, posix_dep, gexiv2_dep, config_dep]
+gala_base_dep = [canberra_dep, glib_dep, gobject_dep, gio_dep, gio_unix_dep, gmodule_dep, gee_dep, gtk_dep, mutter_dep, granite_dep, gnome_desktop_dep, m_dep, posix_dep, gexiv2_dep, config_dep]
 
 if get_option('systemd')
     gala_base_dep += systemd_dep

src/DBus.vala

@@ -33,6 +33,10 @@ namespace Gala {
                     try {
                         connection.register_object ("/org/pantheon/gala", instance);
                     } catch (Error e) { warning (e.message); }
+
+                    try {
+                        connection.register_object ("/org/pantheon/gala/DesktopInterface", new DesktopIntegration (wm));
+                    } catch (Error e) { warning (e.message); }
                 },
                 () => {},
                 () => warning ("Could not acquire name\n") );