lockscreen: Add support for passwordless logins

look-and-feel/contents/lockscreen/FlickContainer.qml

@@ -1,8 +1,5 @@
-/*
- *   SPDX-FileCopyrightText: 2021 Devin Lin <devin@kde.org>
- *
- *   SPDX-License-Identifier: LGPL-2.0-or-later
- */
+// SPDX-FileCopyrightText: 2021-2022 Devin Lin <devin@kde.org>
+// SPDX-License-Identifier: LGPL-2.0-or-later
 
 import QtQuick 2.15
 import QtQuick.Layouts 1.15
@@ -16,6 +13,8 @@ Flickable {
     
     required property real keypadHeight
     
+    signal opened()
+    
     function cancelAnimations() {
         positionAnim.stop();
     }
@@ -45,6 +44,12 @@ Flickable {
         id: positionAnim
         duration: PlasmaCore.Units.longDuration * 2
         easing.type: Easing.OutCubic
+        
+        onFinished: {
+            if (root.position === keypadHeight) {
+                root.opened();
+            }
+        }
     }
     
     // we use flickable solely for capturing flicks, not positioning elements
@@ -55,7 +60,6 @@ Flickable {
     
     readonly property real startContentY: contentHeight / 2
     
-    
     property int oldPosition: position
     property bool movingUp: false 
     

look-and-feel/contents/lockscreen/LockScreen.qml

@@ -69,6 +69,13 @@ PlasmaCore.ColorScope {
         
         property real openFactor: position / keypadHeight
         
+        onOpened: {
+            if (root.lockScreenState.passwordless) {
+                // try unlocking if flicked to the top, and we have passwordless login
+                root.lockScreenState.tryPassword();
+            }
+        }
+        
         keypadHeight: PlasmaCore.Units.gridUnit * 20
         
         // go to closed position when loaded
@@ -162,6 +169,7 @@ PlasmaCore.ColorScope {
             Loader {
                 width: parent.width
                 asynchronous: true
+                active: !root.lockScreenState.passwordless // only load keypad if not passwordless
                 
                 anchors.bottom: parent.bottom
                 

look-and-feel/contents/lockscreen/LockScreenState.qml

@@ -1,8 +1,5 @@
-/*
- * SPDX-FileCopyrightText: 2022 Devin Lin <espidev@gmail.com>
- * 
- * SPDX-License-Identifier: GPL-2.0-or-later
- */
+// SPDX-FileCopyrightText: 2022 Devin Lin <espidev@gmail.com>
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 import QtQml 2.15
 import QtQuick 2.15
@@ -16,8 +13,12 @@ QtObject {
     // whether waiting for authentication after trying password
     property bool waitingForAuth: false
     
+    // the info message given
     property string info: ""
     
+    // whether the lockscreen was passwordless
+    property bool passwordless: true
+    
     signal reset()
     signal unlockSucceeded()
     signal unlockFailed()
@@ -26,6 +27,7 @@ QtObject {
         if (root.password !== '') { // prevent typing lock when password is empty
             waitingForAuth = true;
         }
+        connections.hasPrompt = true;
         authenticator.tryUnlock();
     }
     
@@ -34,21 +36,35 @@ QtObject {
         root.reset();
     }
     
+    Component.onCompleted: {
+        // determine whether we have passwordless login
+        // if we do, authenticator will emit a success signal, otherwise it will emit failure
+        authenticator.tryUnlock();
+    }
+    
     property var connections: Connections {
         target: authenticator
         
+        // false for our test of whether we have passwordless login, otherwise it's true
+        property bool hasPrompt: false
+        
         function onSucceeded() {
-            console.log('login succeeded');
-            root.waitingForAuth = false;
-            root.unlockSucceeded();
-            Qt.quit();
+            if (hasPrompt) {
+                console.log('login succeeded');
+                root.waitingForAuth = false;
+                root.unlockSucceeded();
+                Qt.quit();
+            }
         }
         
         function onFailed() {
-            console.log('login failed');
-            root.waitingForAuth = false;
-            root.password = "";
-            root.unlockFailed();
+            root.passwordless = false;
+            if (hasPrompt) {
+                console.log('login failed');
+                root.waitingForAuth = false;
+                root.password = "";
+                root.unlockFailed();
+            }
         }
         
         function onInfoMessage(msg) {