Add screen lock feature.

Signal/src/util/OWSScreenLock.swift

@@ -12,9 +12,21 @@ import LocalAuthentication
     public enum OWSScreenLockOutcome {
         case success
         case cancel
+//        case userCancel
+//        case otherCancel
         case failure(error:String)
+//        case permanentFailure(error:String)
     }
 
+    @objc public let screenLockTimeouts = [
+        5 * kSecondInterval,
+        15 * kSecondInterval,
+        30 * kSecondInterval,
+        1 * kMinuteInterval,
+        5 * kMinuteInterval,
+        0
+    ]
+
     @objc public static let ScreenLockDidChange = Notification.Name("ScreenLockDidChange")
 
     let primaryStorage: OWSPrimaryStorage
@@ -68,7 +80,8 @@ import LocalAuthentication
             return 0
         }
 
-        return self.dbConnection.double(forKey: OWSScreenLock_Key_ScreenLockTimeoutSeconds, inCollection: OWSScreenLock_Collection, defaultValue: 0)
+        let defaultTimeout = screenLockTimeouts[0]
+        return self.dbConnection.double(forKey: OWSScreenLock_Key_ScreenLockTimeoutSeconds, inCollection: OWSScreenLock_Collection, defaultValue: defaultTimeout)
     }
 
     private func setIsScreenLockEnabled(value: TimeInterval) {

Signal/src/util/OWSScreenLockUI.m

@@ -143,16 +143,7 @@ NS_ASSUME_NONNULL_BEGIN
         OWSAssert(screenLockTimeout >= 0);
         if (self.appBecameInactiveDate && screenLockInterval < screenLockTimeout) {
             // Don't show 'Screen Lock' if 'Screen Lock' timeout hasn't elapsed.
-            shouldHaveScreenProtection = YES;
-
-            // Check again when screen lock timeout should elapse.
-            NSTimeInterval screenLockRemaining = screenLockTimeout - screenLockInterval + 0.2f;
-            OWSAssert(screenLockRemaining >= 0);
-            dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(screenLockRemaining * NSEC_PER_SEC)),
-                dispatch_get_main_queue(),
-                ^{
-                    [self ensureScreenProtection];
-                });
+            shouldHaveScreenLock = NO;
         } else {
             // Otherwise, show 'Screen Lock'.
             shouldHaveScreenLock = YES;
@@ -160,6 +151,11 @@ NS_ASSUME_NONNULL_BEGIN
     }
 
     BOOL shouldShowBlockWindow = shouldHaveScreenProtection || shouldHaveScreenLock;
+    DDLogVerbose(@"%@, shouldHaveScreenProtection: %d, shouldHaveScreenLock: %d, shouldShowBlockWindow: %d",
+        self.logTag,
+        shouldHaveScreenProtection,
+        shouldHaveScreenLock,
+        shouldShowBlockWindow);
     self.screenBlockingWindow.hidden = !shouldShowBlockWindow;
 
     if (shouldHaveScreenLock) {

SignalServiceKit/src/Util/NSDate+OWS.h

@@ -5,6 +5,7 @@
 NS_ASSUME_NONNULL_BEGIN
 
 // These NSTimeInterval constants provide simplified durations for readability.
+extern const NSTimeInterval kSecondInterval;
 extern const NSTimeInterval kMinuteInterval;
 extern const NSTimeInterval kHourInterval;
 extern const NSTimeInterval kDayInterval;

SignalServiceKit/src/Util/NSDate+OWS.mm

@@ -7,6 +7,8 @@
 
 NS_ASSUME_NONNULL_BEGIN
 
+
+const NSTimeInterval kSecondInterval = 1;
 const NSTimeInterval kMinuteInterval = 60;
 const NSTimeInterval kHourInterval = 60 * kMinuteInterval;
 const NSTimeInterval kDayInterval = 24 * kHourInterval;