[gnome-software] gs-details-page: Show a pulsing progress bar if progress is unknown

[Richard Hughes <rhughes src gnome org>]

commit c961c8ff208e744f1ed350601d25f3cc040c3397
Author: Philip Withnall <withnall endlessm com>
Date:   Tue Apr 28 18:28:12 2020 +0100

    gs-details-page: Show a pulsing progress bar if progress is unknown
    
    Use the new unknown progress support (see the previous few commits) to
    display a pulsing progress bar before switching to showing 0% progress
    (and then, hopefully, fairly steady progress 1% onwards). This reduces
    the amount of time for which the UI displays 0% progress, which was
    confusing and frustrating users, who had wondered whether the
    installation failed.
    
    Signed-off-by: Philip Withnall <withnall endlessm com>
    Fixes: #276

 src/gs-details-page.c | 37 ++++++++++++++++++++++++++++++++++++-
 1 file changed, 36 insertions(+), 1 deletion(-)
---
diff --git a/src/gs-details-page.c b/src/gs-details-page.c
index 8eb07bd3..8a9aebbb 100644
--- a/src/gs-details-page.c
+++ b/src/gs-details-page.c
@@ -138,6 +138,7 @@ struct _GsDetailsPage
        GtkWidget               *label_details_kudo_translated;
        GtkWidget               *label_details_kudo_updated;
        GtkWidget               *progressbar_top;
+       guint                    progress_pulse_id;
        GtkWidget               *popover_license_free;
        GtkWidget               *popover_license_nonfree;
        GtkWidget               *popover_license_unknown;
@@ -285,6 +286,25 @@ gs_details_page_switch_to (GsPage *page, gboolean scroll_up)
        gs_grab_focus_when_mapped (self->scrolledwindow_details);
 }
 
+static gboolean
+_pulse_cb (gpointer user_data)
+{
+       GsDetailsPage *self = GS_DETAILS_PAGE (user_data);
+
+       gtk_progress_bar_pulse (GTK_PROGRESS_BAR (self->progressbar_top));
+
+       return G_SOURCE_CONTINUE;
+}
+
+static void
+stop_progress_pulsing (GsDetailsPage *self)
+{
+       if (self->progress_pulse_id != 0) {
+               g_source_remove (self->progress_pulse_id);
+               self->progress_pulse_id = 0;
+       }
+}
+
 static void
 gs_details_page_refresh_progress (GsDetailsPage *self)
 {
@@ -359,10 +379,22 @@ gs_details_page_refresh_progress (GsDetailsPage *self)
        switch (state) {
        case AS_APP_STATE_INSTALLING:
                percentage = gs_app_get_progress (self->app);
-               if (percentage <= 100) {
+               if (percentage == GS_APP_PROGRESS_UNKNOWN) {
+                       /* Translators: This string is shown when preparing to download and install an app. */
+                       gtk_label_set_label (GTK_LABEL (self->label_progress_status), _("Preparing…"));
+                       gtk_widget_set_visible (self->label_progress_status, TRUE);
+                       gtk_widget_set_visible (self->label_progress_percentage, FALSE);
+
+                       if (self->progress_pulse_id == 0)
+                               self->progress_pulse_id = g_timeout_add (50, _pulse_cb, self);
+
+                       gtk_widget_set_visible (self->progressbar_top, TRUE);
+                       break;
+               } else if (percentage <= 100) {
                        g_autofree gchar *str = g_strdup_printf ("%u%%", percentage);
                        gtk_label_set_label (GTK_LABEL (self->label_progress_percentage), str);
                        gtk_widget_set_visible (self->label_progress_percentage, TRUE);
+                       stop_progress_pulsing (self);
                        gtk_progress_bar_set_fraction (GTK_PROGRESS_BAR (self->progressbar_top),
                                                       (gdouble) percentage / 100.f);
                        gtk_widget_set_visible (self->progressbar_top, TRUE);
@@ -372,6 +404,7 @@ gs_details_page_refresh_progress (GsDetailsPage *self)
        default:
                gtk_widget_set_visible (self->label_progress_percentage, FALSE);
                gtk_widget_set_visible (self->progressbar_top, FALSE);
+               stop_progress_pulsing (self);
                break;
        }
        if (app_has_pending_action (self->app)) {
@@ -2655,6 +2688,8 @@ gs_details_page_dispose (GObject *object)
 {
        GsDetailsPage *self = GS_DETAILS_PAGE (object);
 
+       stop_progress_pulsing (self);
+
        if (self->app != NULL) {
                g_signal_handlers_disconnect_by_func (self->app, gs_details_page_notify_state_changed_cb, 
self);
                g_signal_handlers_disconnect_by_func (self->app, gs_details_page_progress_changed_cb, self);