Re-enable and clean up Signal PINs.

- Require PINs during registration agian.
- Change min length to 4.
- Allow the full-screen megaphone to be enabled remotely.
- Clean up and remove some code.

app/src/main/java/org/thoughtcrime/securesms/keyvalue/KbsValues.java

@@ -1,10 +1,8 @@
 package org.thoughtcrime.securesms.keyvalue;
 
-import androidx.annotation.CheckResult;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 
-import org.thoughtcrime.securesms.lock.v2.PinKeyboardType;
 import org.thoughtcrime.securesms.util.JsonUtils;
 import org.whispersystems.signalservice.api.RegistrationLockData;
 import org.whispersystems.signalservice.api.kbs.MasterKey;
@@ -19,7 +17,6 @@ public final class KbsValues {
   private static final String MASTER_KEY          = "kbs.registration_lock_master_key";
   private static final String TOKEN_RESPONSE      = "kbs.token_response";
   private static final String LOCK_LOCAL_PIN_HASH = "kbs.registration_lock_local_pin_hash";
-  private static final String KEYBOARD_TYPE       = "kbs.keyboard_type";
 
   private final KeyValueStore store;
 
@@ -35,7 +32,6 @@ public final class KbsValues {
          .remove(V2_LOCK_ENABLED)
          .remove(TOKEN_RESPONSE)
          .remove(LOCK_LOCAL_PIN_HASH)
-         .remove(KEYBOARD_TYPE)
          .commit();
   }
 
@@ -97,15 +93,15 @@ public final class KbsValues {
     }
   }
 
-  public @Nullable String getLocalPinHash() {
+  public synchronized @Nullable String getLocalPinHash() {
     return store.getString(LOCK_LOCAL_PIN_HASH, null);
   }
 
-  public boolean isV2RegistrationLockEnabled() {
+  public synchronized boolean isV2RegistrationLockEnabled() {
     return store.getBoolean(V2_LOCK_ENABLED, false);
   }
 
-  public @Nullable TokenResponse getRegistrationLockTokenResponse() {
+  public synchronized @Nullable TokenResponse getRegistrationLockTokenResponse() {
     String token = store.getString(TOKEN_RESPONSE, null);
 
     if (token == null) return null;
@@ -116,19 +112,4 @@ public final class KbsValues {
       throw new AssertionError(e);
     }
   }
-
-  public void setKeyboardType(@NonNull PinKeyboardType keyboardType) {
-    store.beginWrite()
-         .putString(KEYBOARD_TYPE, keyboardType.getCode())
-         .commit();
-  }
-
-  @CheckResult
-  public @NonNull PinKeyboardType getKeyboardType() {
-    return PinKeyboardType.fromCode(store.getString(KEYBOARD_TYPE, null));
-  }
-
-  public boolean hasMigratedToPinsForAll() {
-    return store.getString(KEYBOARD_TYPE, null) != null && store.getBoolean(V2_LOCK_ENABLED, false);
-  }
 }

app/src/main/java/org/thoughtcrime/securesms/keyvalue/PinValues.java

@@ -1,16 +1,24 @@
 package org.thoughtcrime.securesms.keyvalue;
 
+import androidx.annotation.CheckResult;
+import androidx.annotation.NonNull;
+
 import org.thoughtcrime.securesms.dependencies.ApplicationDependencies;
 import org.thoughtcrime.securesms.lock.SignalPinReminders;
+import org.thoughtcrime.securesms.lock.v2.PinKeyboardType;
 import org.thoughtcrime.securesms.logging.Log;
 import org.thoughtcrime.securesms.util.TextSecurePreferences;
 
+/**
+ * Specifically handles just the UI/UX state around PINs. For actual keys, see {@link KbsValues}.
+ */
 public final class PinValues {
 
   private static final String TAG = Log.tag(PinValues.class);
 
   private static final String LAST_SUCCESSFUL_ENTRY = "pin.last_successful_entry";
   private static final String NEXT_INTERVAL         = "pin.interval_index";
+  private static final String KEYBOARD_TYPE         = "kbs.keyboard_type";
 
   private final KeyValueStore store;
 
@@ -47,7 +55,6 @@ public final class PinValues {
          .apply();
   }
 
-
   public void onPinChange() {
     long nextInterval = SignalPinReminders.INITIAL_INTERVAL;
     Log.i(TAG, "onPinChange() nextInterval: " + nextInterval);
@@ -65,4 +72,14 @@ public final class PinValues {
   public long getLastSuccessfulEntryTime() {
     return store.getLong(LAST_SUCCESSFUL_ENTRY, TextSecurePreferences.getRegistrationLockLastReminderTime(ApplicationDependencies.getApplication()));
   }
+
+  public void setKeyboardType(@NonNull PinKeyboardType keyboardType) {
+    store.beginWrite()
+         .putString(KEYBOARD_TYPE, keyboardType.getCode())
+         .commit();
+  }
+
+  public @NonNull PinKeyboardType getKeyboardType() {
+    return PinKeyboardType.fromCode(store.getString(KEYBOARD_TYPE, null));
+  }
 }

app/src/main/java/org/thoughtcrime/securesms/keyvalue/RegistrationValues.java

@@ -17,8 +17,7 @@ public final class RegistrationValues {
   public synchronized void onFirstEverAppLaunch() {
     store.beginWrite()
          .putBoolean(REGISTRATION_COMPLETE, false)
-         // TODO [greyson] [pins] Maybe re-enable in the future
-//         .putBoolean(PIN_REQUIRED, true)
+         .putBoolean(PIN_REQUIRED, true)
          .commit();
   }