From b012efc12d005d2ecde82398d7a230deab6842cc Mon Sep 17 00:00:00 2001
From: Matthew Chen <matthew@signal.org>
Date: Thu, 22 Mar 2018 17:28:05 -0400
Subject: [PATCH] Fix screen lock presentation logic.

---
 Signal/src/util/OWSScreenLock.swift | 19 +++++++++++++++++++
 Signal/src/util/OWSScreenLockUI.m   |  8 +++++---
 2 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/Signal/src/util/OWSScreenLock.swift b/Signal/src/util/OWSScreenLock.swift
index fffe6de24b..ad054ed57b 100644
--- a/Signal/src/util/OWSScreenLock.swift
+++ b/Signal/src/util/OWSScreenLock.swift
@@ -32,6 +32,10 @@ import LocalAuthentication
     private let OWSScreenLock_Key_IsScreenLockEnabled = "OWSScreenLock_Key_IsScreenLockEnabled"
     private let OWSScreenLock_Key_ScreenLockTimeoutSeconds = "OWSScreenLock_Key_ScreenLockTimeoutSeconds"
 
+    // We don't want the verification process itself to trigger unlock verification.
+    // Passcode-code only authentication process deactivates the app.
+    private var ignoreUnlock = false
+
     // MARK - Singleton class
 
     @objc(sharedManager)
@@ -137,6 +141,13 @@ import LocalAuthentication
     @objc public func tryToUnlockScreenLock(success: @escaping (() -> Void),
                                             failure: @escaping ((Error) -> Void),
                                             cancel: @escaping (() -> Void)) {
+        guard !ignoreUnlock else {
+            DispatchQueue.main.async {
+                success()
+            }
+            return
+        }
+
         tryToVerifyLocalAuthentication(localizedReason: NSLocalizedString("SCREEN_LOCK_REASON_UNLOCK_SCREEN_LOCK",
                                                                         comment: "Description of how and why Signal iOS uses Touch ID/Face ID/Phone Passcode to unlock 'screen lock'."),
                                        completion: { (outcome: OWSScreenLockOutcome) in
@@ -159,6 +170,7 @@ import LocalAuthentication
     // isScreenLockEnabled.
     private func tryToVerifyLocalAuthentication(localizedReason: String,
                                                 completion completionParam: @escaping ((OWSScreenLockOutcome) -> Void)) {
+        AssertIsOnMainThread()
 
         // Ensure completion is always called on the main thread.
         let completion = { (outcome: OWSScreenLockOutcome) in
@@ -194,7 +206,14 @@ import LocalAuthentication
             return
         }
 
+        // Use ignoreUnlock to suppress unlock verifications.
+        ignoreUnlock = true
         context.evaluatePolicy(.deviceOwnerAuthentication, localizedReason: localizedReason) { success, evaluateError in
+
+            DispatchQueue.main.async {
+                self.ignoreUnlock = false
+            }
+
             if success {
                 Logger.info("\(self.logTag) local authentication succeeded.")
                 completion(.success)
diff --git a/Signal/src/util/OWSScreenLockUI.m b/Signal/src/util/OWSScreenLockUI.m
index d0e26d6119..c86c1ddbed 100644
--- a/Signal/src/util/OWSScreenLockUI.m
+++ b/Signal/src/util/OWSScreenLockUI.m
@@ -117,9 +117,7 @@ NS_ASSUME_NONNULL_BEGIN
     }
 
     BOOL shouldHaveScreenLock = NO;
-    if (self.appIsInactive) {
-        // Don't show 'Screen Lock' if app is inactive.
-    } else if (![TSAccountManager isRegistered]) {
+    if (![TSAccountManager isRegistered]) {
         // Don't show 'Screen Lock' if user is not registered.
     } else if (!OWSScreenLock.sharedManager.isScreenLockEnabled) {
         // Don't show 'Screen Lock' if 'Screen Lock' isn't enabled.
@@ -128,6 +126,9 @@ NS_ASSUME_NONNULL_BEGIN
     } else if (!self.appBecameInactiveDate) {
         // Show 'Screen Lock' if app hasn't become inactive yet (just launched).
         shouldHaveScreenLock = YES;
+        DDLogVerbose(@"%@, shouldHaveScreenLock 2: %d", self.logTag, self.appIsInactive);
+    } else if (!self.appIsInactive) {
+        // Don't show 'Screen Lock' if app is inactive.
     } else {
         OWSAssert(self.appBecameInactiveDate);
 
@@ -141,6 +142,7 @@ NS_ASSUME_NONNULL_BEGIN
         } else {
             // Otherwise, show 'Screen Lock'.
             shouldHaveScreenLock = YES;
+            DDLogVerbose(@"%@, shouldHaveScreenLock 1: %d", self.logTag, self.appIsInactive);
         }
     }