[gnome-shell/mcatanzaro/#2717] endSessionDialog: default to not installing updates on low battery

[Michael Catanzaro <mcatanzaro src gnome org>]

commit 7d9e26c97dcd6d50f38b4d2811c1e854b96baf3d
Author: Michael Catanzaro <mcatanzaro gnome org>
Date:   Fri Jul 24 19:08:16 2020 -0500

    endSessionDialog: default to not installing updates on low battery
    
    If the user's battery power is low, we should not check the checkbox to
    install updates by default. Rationale: if the user's battery is not low,
    it's very unlikely to run out during a normal system upgrade. Low
    battery is defined as any level below 30%, matching our battery status
    indicator.
    
    We'll also change the battery warning to only display when battery is
    actually low. However, we will still always warn on battery for full
    system upgrades, since these are expected to take a long time.
    
    Future improvement: it would be nice to make the checkbox insensitive
    when on low power. However, I don't think we currently have a proper
    style for insensitive checkboxes. I was unable to make it look good.
    
    Lastly, note that I did not test this on a laptop. I tested this by
    mocking the return values of _isDischargingBattery() and
    _isBatteryLow().
    
    Fixes https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/2717

 js/ui/endSessionDialog.js | 39 +++++++++++++++++++++++++++++----------
 1 file changed, 29 insertions(+), 10 deletions(-)
---
diff --git a/js/ui/endSessionDialog.js b/js/ui/endSessionDialog.js
index b936352f48..4c69443450 100644
--- a/js/ui/endSessionDialog.js
+++ b/js/ui/endSessionDialog.js
@@ -18,7 +18,7 @@
  */
 
 const { AccountsService, Clutter, Gio,
-        GLib, GObject, Pango, Polkit, Shell, St }  = imports.gi;
+        GLib, GObject, Pango, Polkit, Shell, St, UPowerGlib: UPower }  = imports.gi;
 
 const CheckBox = imports.ui.checkBox;
 const Dialog = imports.ui.dialog;
@@ -47,6 +47,7 @@ const logoutDialogContent = {
                         seconds).format(seconds);
     },
     showBatteryWarning: false,
+    isSystemUpgrade: false,
     confirmButtons: [{ signal: 'ConfirmedLogout',
                        label: C_("button", "Log Out") }],
     showOtherSessions: false,
@@ -62,6 +63,7 @@ const shutdownDialogContent = {
     },
     checkBoxText: C_("checkbox", "Install pending software updates"),
     showBatteryWarning: true,
+    isSystemUpgrade: false,
     confirmButtons: [{ signal: 'ConfirmedReboot',
                        label: C_("button", "Restart") },
                      { signal: 'ConfirmedShutdown',
@@ -78,6 +80,7 @@ const restartDialogContent = {
                         seconds).format(seconds);
     },
     showBatteryWarning: false,
+    isSystemUpgrade: false,
     confirmButtons: [{ signal: 'ConfirmedReboot',
                        label: C_("button", "Restart") }],
     iconName: 'view-refresh-symbolic',
@@ -93,6 +96,7 @@ const restartUpdateDialogContent = {
                         seconds).format(seconds);
     },
     showBatteryWarning: true,
+    isSystemUpgrade: false,
     confirmButtons: [{ signal: 'ConfirmedReboot',
                        label: C_("button", "Restart &amp; Install") }],
     unusedFutureButtonForTranslation: C_("button", "Install &amp; Power Off"),
@@ -112,6 +116,7 @@ const restartUpgradeDialogContent = {
     },
     disableTimer: true,
     showBatteryWarning: false,
+    isSystemUpgrade: true,
     confirmButtons: [{ signal: 'ConfirmedReboot',
                        label: C_("button", "Restart &amp; Install") }],
     iconName: 'view-refresh-symbolic',
@@ -142,7 +147,7 @@ const LogindSession = Gio.DBusProxy.makeProxyWrapper(LogindSessionIface);
 const PkOfflineIface = loadInterfaceXML('org.freedesktop.PackageKit.Offline');
 const PkOfflineProxy = Gio.DBusProxy.makeProxyWrapper(PkOfflineIface);
 
-const UPowerIface = loadInterfaceXML('org.freedesktop.UPower');
+const UPowerIface = loadInterfaceXML('org.freedesktop.UPower.Device');
 const UPowerProxy = Gio.DBusProxy.makeProxyWrapper(UPowerIface);
 
 function findAppFromInhibitor(inhibitor) {
@@ -224,7 +229,7 @@ class EndSessionDialog extends ModalDialog.ModalDialog {
 
         this._powerProxy = new UPowerProxy(Gio.DBus.system,
                                            'org.freedesktop.UPower',
-                                           '/org/freedesktop/UPower',
+                                           '/org/freedesktop/UPower/devices/DisplayDevice',
                                            (proxy, error) => {
                                                if (error) {
                                                    log(error.message);
@@ -256,7 +261,7 @@ class EndSessionDialog extends ModalDialog.ModalDialog {
 
         this._batteryWarning = new St.Label({
             style_class: 'end-session-dialog-battery-warning',
-            text: _('Running on battery power: Please plug in before installing updates.'),
+            text: _('Low battery power: please plug in before installing updates.'),
         });
         this._batteryWarning.clutter_text.ellipsize = Pango.EllipsizeMode.NONE;
         this._batteryWarning.clutter_text.line_wrap = true;
@@ -306,6 +311,16 @@ class EndSessionDialog extends ModalDialog.ModalDialog {
         this._user.disconnect(this._userChangedId);
     }
 
+    _isDischargingBattery() {
+        return this._powerProxy.IsPresent &&
+               this._powerProxy.State !== UPower.DeviceState.CHARGING &&
+               this._powerProxy.State !== UPower.DeviceState.FULLY_CHARGED;
+    }
+
+    _isBatteryLow() {
+        return this._isDischargingBattery() && this._powerProxy.Percentage < 30;
+    }
+
     _sync() {
         let open = this.state == ModalDialog.State.OPENING || this.state == ModalDialog.State.OPENED;
         if (!open)
@@ -319,10 +334,9 @@ class EndSessionDialog extends ModalDialog.ModalDialog {
         if (dialogContent.subjectWithUpdates && this._checkBox.checked)
             subject = dialogContent.subjectWithUpdates;
 
-        if (dialogContent.showBatteryWarning) {
-            this._batteryWarning.visible =
-                this._powerProxy.OnBattery && this._checkBox.checked;
-        }
+        // Hide battery warning if the user has plugged in.
+        if (this._batteryWarning.visible)
+            this._batteryWarning.visible = this._isDischargingBattery();
 
         let description;
         let displayTime = _roundSecondsToInterval(this._totalSecondsToStayOpen,
@@ -677,13 +691,18 @@ class EndSessionDialog extends ModalDialog.ModalDialog {
 
         _setCheckBoxLabel(this._checkBox, dialogContent.checkBoxText || '');
         this._checkBox.visible = dialogContent.checkBoxText && updatePrepared && updatesAllowed;
-        this._checkBox.checked = this._checkBox.visible;
+
+        if (dialogContent.isSystemUpgrade)
+            this._checkBox.checked = this._checkBox.visible && updateTriggered && 
!this._isDischargingBattery();
+        else
+            this._checkBox.checked = this._checkBox.visible && !this._isBatteryLow();
 
         // We show the warning either together with the checkbox, or when
         // updates have already been triggered, but the user doesn't have
         // enough permissions to cancel them.
         this._batteryWarning.visible = dialogContent.showBatteryWarning &&
-                                        (this._checkBox.visible || updatePrepared && updateTriggered && 
!updatesAllowed);
+                                       this._isBatteryLow() &&
+                                       (this._checkBox.visible || updatePrepared && updateTriggered && 
!updatesAllowed);
 
         this._updateButtons();