Modify TSStorageManager to use separate shared read and write connections.

// FREEBIE

src/Contacts/Contact.m

@@ -244,13 +244,12 @@ NS_ASSUME_NONNULL_BEGIN
 - (NSArray<NSString *> *)textSecureIdentifiers {
     __block NSMutableArray *identifiers = [NSMutableArray array];
 
-    [[TSStorageManager sharedManager]
-            .dbConnection readWithBlock:^(YapDatabaseReadTransaction *transaction) {
-      for (PhoneNumber *number in self.parsedPhoneNumbers) {
-          if ([SignalRecipient recipientWithTextSecureIdentifier:number.toE164 withTransaction:transaction]) {
-              [identifiers addObject:number.toE164];
-          }
-      }
+    [[TSStorageManager sharedManager].dbReadConnection readWithBlock:^(YapDatabaseReadTransaction *transaction) {
+        for (PhoneNumber *number in self.parsedPhoneNumbers) {
+            if ([SignalRecipient recipientWithTextSecureIdentifier:number.toE164 withTransaction:transaction]) {
+                [identifiers addObject:number.toE164];
+            }
+        }
     }];
     return [identifiers copy];
 }

src/Contacts/ContactsUpdater.m

@@ -122,11 +122,11 @@ NS_ASSUME_NONNULL_BEGIN
     }
 
     NSMutableSet *recipientIds = [NSMutableSet set];
-    [[TSStorageManager sharedManager]
-            .dbConnection readWithBlock:^(YapDatabaseReadTransaction *_Nonnull transaction) {
-      NSArray *allRecipientKeys = [transaction allKeysInCollection:[SignalRecipient collection]];
-      [recipientIds addObjectsFromArray:allRecipientKeys];
-    }];
+    [[TSStorageManager sharedManager].dbReadConnection
+        readWithBlock:^(YapDatabaseReadTransaction *_Nonnull transaction) {
+            NSArray *allRecipientKeys = [transaction allKeysInCollection:[SignalRecipient collection]];
+            [recipientIds addObjectsFromArray:allRecipientKeys];
+        }];
 
     NSMutableSet<NSString *> *allContacts = [[abPhoneNumbers setByAddingObjectsFromSet:recipientIds] mutableCopy];
 
@@ -135,7 +135,7 @@ NS_ASSUME_NONNULL_BEGIN
                                  [recipientIds minusSet:matchedIds];
 
                                  // Cleaning up unregistered identifiers
-                                 [[TSStorageManager sharedManager].dbConnection
+                                 [[TSStorageManager sharedManager].dbReadWriteConnection
                                      readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
                                          for (NSString *identifier in recipientIds) {
                                              SignalRecipient *recipient =
@@ -185,23 +185,22 @@ NS_ASSUME_NONNULL_BEGIN
             }
 
             // Insert or update contact attributes
-            [[TSStorageManager sharedManager]
-                    .dbConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
-              for (NSString *identifier in attributesForIdentifier) {
-                  SignalRecipient *recipient =
-                      [SignalRecipient recipientWithTextSecureIdentifier:identifier withTransaction:transaction];
-                  if (!recipient) {
-                      recipient = [[SignalRecipient alloc] initWithTextSecureIdentifier:identifier
-                                                                                  relay:nil];
-                  }
+            [[TSStorageManager sharedManager].dbReadWriteConnection
+                readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
+                    for (NSString *identifier in attributesForIdentifier) {
+                        SignalRecipient *recipient =
+                            [SignalRecipient recipientWithTextSecureIdentifier:identifier withTransaction:transaction];
+                        if (!recipient) {
+                            recipient = [[SignalRecipient alloc] initWithTextSecureIdentifier:identifier relay:nil];
+                        }
 
-                  NSDictionary *attributes = [attributesForIdentifier objectForKey:identifier];
+                        NSDictionary *attributes = [attributesForIdentifier objectForKey:identifier];
 
-                  recipient.relay = attributes[@"relay"];
+                        recipient.relay = attributes[@"relay"];
 
-                  [recipient saveWithTransaction:transaction];
-              }
-            }];
+                        [recipient saveWithTransaction:transaction];
+                    }
+                }];
 
             success([NSSet setWithArray:attributesForIdentifier.allKeys]);
           }

src/Contacts/SignalRecipient.m

@@ -37,7 +37,7 @@ NS_ASSUME_NONNULL_BEGIN
 + (nullable instancetype)recipientWithTextSecureIdentifier:(NSString *)textSecureIdentifier
 {
     __block SignalRecipient *recipient;
-    [self.dbConnection readWithBlock:^(YapDatabaseReadTransaction *_Nonnull transaction) {
+    [self.dbReadConnection readWithBlock:^(YapDatabaseReadTransaction *_Nonnull transaction) {
         recipient = [self recipientWithTextSecureIdentifier:textSecureIdentifier withTransaction:transaction];
     }];
     return recipient;

src/Contacts/TSThread.m

@@ -131,7 +131,7 @@ NS_ASSUME_NONNULL_BEGIN
  */
 - (void)enumerateInteractionsUsingBlock:(void (^)(TSInteraction *interaction))block
 {
-    [self.dbConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
+    [self.dbReadWriteConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
         [self enumerateInteractionsWithTransaction:transaction
                                         usingBlock:^(
                                             TSInteraction *interaction, YapDatabaseReadTransaction *transaction) {
@@ -172,7 +172,7 @@ NS_ASSUME_NONNULL_BEGIN
 - (NSUInteger)numberOfInteractions
 {
     __block NSUInteger count;
-    [[self dbConnection] readWithBlock:^(YapDatabaseReadTransaction *_Nonnull transaction) {
+    [[self dbReadConnection] readWithBlock:^(YapDatabaseReadTransaction *_Nonnull transaction) {
         YapDatabaseViewTransaction *interactionsByThread = [transaction ext:TSMessageDatabaseViewExtensionName];
         count = [interactionsByThread numberOfItemsInGroup:self.uniqueId];
     }];
@@ -237,7 +237,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (TSInteraction *) lastInteraction {
     __block TSInteraction *last;
-    [TSStorageManager.sharedManager.dbConnection readWithBlock:^(YapDatabaseReadTransaction *transaction){
+    [TSStorageManager.sharedManager.dbReadConnection readWithBlock:^(YapDatabaseReadTransaction *transaction) {
         last = [[transaction ext:TSMessageDatabaseViewExtensionName] lastObjectInGroup:self.uniqueId];
     }];
     return last;
@@ -246,7 +246,7 @@ NS_ASSUME_NONNULL_BEGIN
 - (TSInteraction *)lastInteractionForInbox
 {
     __block TSInteraction *last = nil;
-    [TSStorageManager.sharedManager.dbConnection readWithBlock:^(YapDatabaseReadTransaction *transaction) {
+    [TSStorageManager.sharedManager.dbReadConnection readWithBlock:^(YapDatabaseReadTransaction *transaction) {
         [[transaction ext:TSMessageDatabaseViewExtensionName]
             enumerateRowsInGroup:self.uniqueId
                      withOptions:NSEnumerationReverse
@@ -397,7 +397,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (void)updateWithMutedUntilDate:(NSDate *)mutedUntilDate
 {
-    [self.dbConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
+    [self.dbReadWriteConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
         [self applyChangeToSelfAndLatestThread:transaction
                                             changeBlock:^(TSThread *thread) {
                                                 [thread setMutedUntilDate:mutedUntilDate];

src/Contacts/Threads/TSContactThread.m

@@ -76,7 +76,7 @@ NS_ASSUME_NONNULL_BEGIN
     OWSAssert(contactId.length > 0);
 
     __block TSContactThread *thread;
-    [[self dbConnection] readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
+    [[self dbReadWriteConnection] readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
         thread = [self getOrCreateThreadWithContactId:contactId transaction:transaction];
     }];
 

src/Contacts/Threads/TSGroupThread.m

@@ -91,7 +91,7 @@ NS_ASSUME_NONNULL_BEGIN
     OWSAssert(groupModel.groupId.length > 0);
 
     __block TSGroupThread *thread;
-    [[self dbConnection] readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
+    [[self dbReadWriteConnection] readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
         thread = [self getOrCreateThreadWithGroupModel:groupModel transaction:transaction];
     }];
     return thread;

src/Devices/OWSReadReceipt.m

@@ -1,4 +1,6 @@
-//  Copyright © 2016 Open Whisper Systems. All rights reserved.
+//
+//  Copyright (c) 2017 Open Whisper Systems. All rights reserved.
+//
 
 #import "OWSReadReceipt.h"
 #import <YapDatabase/YapDatabase.h>
@@ -104,7 +106,7 @@ NSString *const OWSReadReceiptColumnSenderId = @"senderId";
         stringWithFormat:@"WHERE %@ = ? AND %@ = ?", OWSReadReceiptColumnSenderId, OWSReadReceiptColumnTimestamp];
     YapDatabaseQuery *query = [YapDatabaseQuery queryWithFormat:queryFormat, senderId, @(timestamp)];
 
-    [[self dbConnection] readWithBlock:^(YapDatabaseReadTransaction *_Nonnull transaction) {
+    [[self dbReadConnection] readWithBlock:^(YapDatabaseReadTransaction *_Nonnull transaction) {
         [[transaction ext:OWSReadReceiptIndexOnSenderIdAndTimestamp]
             enumerateKeysAndObjectsMatchingQuery:query
                                       usingBlock:^(NSString *collection, NSString *key, id object, BOOL *stop) {

src/Devices/OWSReadReceiptsProcessor.m

@@ -94,7 +94,8 @@ NSString *const OWSReadReceiptsProcessorMarkedMessageAsReadNotification =
             // Always mark the message specified by the read receipt as read.
             [interactionsToMarkAsRead addObject:message];
 
-            [self.storageManager.dbConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
+            [self.storageManager.dbReadWriteConnection readWriteWithBlock:^(
+                YapDatabaseReadWriteTransaction *transaction) {
                 [[TSDatabaseView unseenDatabaseViewExtension:transaction]
                     enumerateRowsInGroup:message.uniqueThreadId
                               usingBlock:^(NSString *collection,

src/Messages/Attachments/TSAttachmentStream.m

@@ -387,7 +387,7 @@ NS_ASSUME_NONNULL_BEGIN
     if (transaction) {
         updateDataStore(transaction);
     } else {
-        [self.dbConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
+        [self.dbReadWriteConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
             updateDataStore(transaction);
         }];
     }
@@ -458,7 +458,7 @@ NS_ASSUME_NONNULL_BEGIN
     if (transaction) {
         updateDataStore(transaction);
     } else {
-        [self.dbConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
+        [self.dbReadWriteConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
             updateDataStore(transaction);
         }];
     }

src/Messages/Interactions/TSIncomingMessage.m

@@ -78,7 +78,7 @@ NSString *const TSIncomingMessageWasReadOnThisDeviceNotification = @"TSIncomingM
 + (nullable instancetype)findMessageWithAuthorId:(NSString *)authorId timestamp:(uint64_t)timestamp
 {
     __block TSIncomingMessage *foundMessage;
-    [self.dbConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
+    [self.dbReadWriteConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
         // In theory we could build a new secondaryIndex for (authorId,timestamp), but in practice there should
         // be *very* few (millisecond) timestamps with multiple authors.
         [TSDatabaseSecondaryIndexes

src/Messages/Interactions/TSOutgoingMessage.m

@@ -245,7 +245,7 @@ NSString *const kTSOutgoingMessageSentRecipientAll = @"kTSOutgoingMessageSentRec
 {
     OWSAssert(error);
 
-    [self.dbConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
+    [self.dbReadWriteConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
         [self applyChangeToSelfAndLatestOutgoingMessage:transaction
                                             changeBlock:^(TSOutgoingMessage *message) {
                                                 [message setMessageState:TSOutgoingMessageStateUnsent];
@@ -256,7 +256,7 @@ NSString *const kTSOutgoingMessageSentRecipientAll = @"kTSOutgoingMessageSentRec
 
 - (void)updateWithMessageState:(TSOutgoingMessageState)messageState
 {
-    [self.dbConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
+    [self.dbReadWriteConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
         [self updateWithMessageState:messageState transaction:transaction];
     }];
 }
@@ -274,7 +274,7 @@ NSString *const kTSOutgoingMessageSentRecipientAll = @"kTSOutgoingMessageSentRec
 
 - (void)updateWithHasSyncedTranscript:(BOOL)hasSyncedTranscript
 {
-    [self.dbConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
+    [self.dbReadWriteConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
         [self applyChangeToSelfAndLatestOutgoingMessage:transaction
                                             changeBlock:^(TSOutgoingMessage *message) {
                                                 [message setHasSyncedTranscript:hasSyncedTranscript];
@@ -295,7 +295,7 @@ NSString *const kTSOutgoingMessageSentRecipientAll = @"kTSOutgoingMessageSentRec
 
 - (void)updateWithCustomMessage:(NSString *)customMessage
 {
-    [self.dbConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
+    [self.dbReadWriteConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
         [self updateWithCustomMessage:customMessage transaction:transaction];
     }];
 }
@@ -312,14 +312,14 @@ NSString *const kTSOutgoingMessageSentRecipientAll = @"kTSOutgoingMessageSentRec
 
 - (void)updateWithWasDelivered
 {
-    [self.dbConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
+    [self.dbReadWriteConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
         [self updateWithWasDeliveredWithTransaction:transaction];
     }];
 }
 
 - (void)updateWithWasSentAndDelivered
 {
-    [self.dbConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
+    [self.dbReadWriteConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
         [self applyChangeToSelfAndLatestOutgoingMessage:transaction
                                             changeBlock:^(TSOutgoingMessage *message) {
                                                 [message setMessageState:TSOutgoingMessageStateSentToService];
@@ -397,7 +397,7 @@ NSString *const kTSOutgoingMessageSentRecipientAll = @"kTSOutgoingMessageSentRec
 
 - (void)updateWithSentRecipient:(NSString *)contactId
 {
-    [self.dbConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
+    [self.dbReadWriteConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
         [self updateWithSentRecipient:contactId transaction:transaction];
     }];
 }

src/Messages/OWSIdentityManager.m

@@ -423,7 +423,7 @@ NSString *const kNSNotificationName_IdentityStateDidChange = @"kNSNotificationNa
         [messages addObject:[TSErrorMessage nonblockingIdentityChangeInThread:groupThread recipientId:recipientId]];
     }
 
-    [self.storageManager.dbConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
+    [self.storageManager.dbReadWriteConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
         for (TSMessage *message in messages) {
             [message saveWithTransaction:transaction];
         }
@@ -452,7 +452,8 @@ NSString *const kNSNotificationName_IdentityStateDidChange = @"kNSNotificationNa
         @synchronized(self)
         {
             NSMutableArray<NSString *> *recipientIds = [NSMutableArray new];
-            [self.storageManager.dbConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
+            [self.storageManager.dbReadWriteConnection readWriteWithBlock:^(
+                YapDatabaseReadWriteTransaction *transaction) {
                 [transaction enumerateKeysAndObjectsInCollection:OWSIdentityManager_QueuedVerificationStateSyncMessages
                                                       usingBlock:^(NSString *_Nonnull recipientId,
                                                                    id _Nonnull object,
@@ -731,7 +732,7 @@ NSString *const kNSNotificationName_IdentityStateDidChange = @"kNSNotificationNa
                                                                      isLocalChange:isLocalChange]];
     }
 
-    [self.storageManager.dbConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
+    [self.storageManager.dbReadWriteConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
         for (TSMessage *message in messages) {
             [message saveWithTransaction:transaction];
         }

src/Messages/TSCall.m

@@ -116,7 +116,7 @@ NSUInteger TSCallCurrentSchemaVersion = 1;
 
     _callType = callType;
 
-    [self.dbConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *_Nonnull transaction) {
+    [self.dbReadWriteConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *_Nonnull transaction) {
         [self saveWithTransaction:transaction];
 
         // redraw any thread-related unread count UI.

src/Messages/TSMessagesManager.m

@@ -525,7 +525,7 @@ NS_ASSUME_NONNULL_BEGIN
             NSString *recipientId = incomingEnvelope.source;
 
             __block TSThread *thread;
-            [[TSStorageManager sharedManager].dbConnection
+            [[TSStorageManager sharedManager].dbReadWriteConnection
                 readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
                     thread = [TSContactThread getOrCreateThreadWithContactId:recipientId transaction:transaction];
                 }];

src/Security/OWSRecipientIdentity.m

@@ -91,7 +91,7 @@ OWSSignalServiceProtosVerifiedState OWSVerificationStateToProtoState(OWSVerifica
 {
     changeBlock(self);
 
-    [[self class].dbConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *_Nonnull transaction) {
+    [[self class].dbReadWriteConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *_Nonnull transaction) {
         OWSRecipientIdentity *latest = [[self class] fetchObjectWithUniqueID:self.uniqueId transaction:transaction];
         if (latest == nil) {
             [self saveWithTransaction:transaction];

src/Storage/AxolotlStore/TSStorageManager+SignedPreKeyStore.m

@@ -148,7 +148,7 @@ NSString *const TSStorageManagerKeyPrekeyCurrentSignedPrekeyId = @"currentSigned
     NSDate *firstPrekeyUpdateFailureDate = [self firstPrekeyUpdateFailureDate];
     NSUInteger prekeyUpdateFailureCount = [self prekeyUpdateFailureCount];
 
-    [self.dbConnection readWithBlock:^(YapDatabaseReadTransaction *_Nonnull transaction) {
+    [self.dbReadConnection readWithBlock:^(YapDatabaseReadTransaction *_Nonnull transaction) {
         __block int i = 0;
 
         DDLogInfo(@"%@ SignedPreKeys Report:", tag);

src/Storage/OWSOrphanedDataCleaner.m

@@ -1,4 +1,6 @@
-// Copyright (c) 2016 Open Whisper Systems. All rights reserved.
+//
+//  Copyright (c) 2017 Open Whisper Systems. All rights reserved.
+//
 
 #import "OWSOrphanedDataCleaner.h"
 #import "TSAttachmentStream.h"
@@ -32,7 +34,7 @@
 - (NSArray<NSString *> *)orphanedInteractionIds
 {
     NSMutableArray *interactionIds = [NSMutableArray new];
-    [[TSInteraction dbConnection] readWithBlock:^(YapDatabaseReadTransaction *_Nonnull transaction) {
+    [[TSInteraction dbReadConnection] readWithBlock:^(YapDatabaseReadTransaction *_Nonnull transaction) {
         [TSInteraction enumerateCollectionObjectsWithTransaction:transaction
                                                       usingBlock:^(TSInteraction *interaction, BOOL *stop) {
                                                           TSThread *thread = [TSThread

src/Storage/TSStorageManager+keyingMaterial.m

@@ -53,7 +53,7 @@
 
 - (void)storePhoneNumber:(NSString *)phoneNumber
 {
-    [self.dbConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
+    [self.dbReadWriteConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
         [transaction setObject:phoneNumber
                         forKey:TSStorageRegisteredNumberKey
                   inCollection:TSStorageUserAccountCollection];
@@ -61,13 +61,12 @@
 }
 
 + (void)storeServerToken:(NSString *)authToken signalingKey:(NSString *)signalingKey {
-    YapDatabaseConnection *dbConn = [[self sharedManager] dbConnection];
-
-    [dbConn readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
-      [transaction setObject:authToken forKey:TSStorageServerAuthToken inCollection:TSStorageUserAccountCollection];
-      [transaction setObject:signalingKey
-                      forKey:TSStorageServerSignalingKey
-                inCollection:TSStorageUserAccountCollection];
+    TSStorageManager *sharedManager = self.sharedManager;
+    [sharedManager.dbReadWriteConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
+        [transaction setObject:authToken forKey:TSStorageServerAuthToken inCollection:TSStorageUserAccountCollection];
+        [transaction setObject:signalingKey
+                        forKey:TSStorageServerSignalingKey
+                  inCollection:TSStorageUserAccountCollection];
 
     }];
 }

src/Storage/TSStorageManager.h

@@ -61,7 +61,8 @@ NS_ASSUME_NONNULL_BEGIN
 - (nullable SignedPreKeyRecord *)signedPreKeyRecordForKey:(NSString *)key inCollection:(NSString *)collection;
 - (void)purgeCollection:(NSString *)collection;
 
-@property (nullable, nonatomic, readonly) YapDatabaseConnection *dbConnection;
+@property (nullable, nonatomic, readonly) YapDatabaseConnection *dbReadConnection;
+@property (nullable, nonatomic, readonly) YapDatabaseConnection *dbReadWriteConnection;
 
 @end
 

src/Storage/TSStorageManager.m

@@ -156,7 +156,8 @@ static NSString *keychainDBPassAccount    = @"TSDatabasePass";
     if (!_database) {
         return NO;
     }
-    _dbConnection = self.newDatabaseConnection;
+    _dbReadConnection = self.newDatabaseConnection;
+    _dbReadWriteConnection = self.newDatabaseConnection;
 
     return YES;
 }
@@ -388,19 +389,19 @@ static NSString *keychainDBPassAccount    = @"TSDatabasePass";
 #pragma mark - convenience methods
 
 - (void)purgeCollection:(NSString *)collection {
-    [self.dbConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
-      [transaction removeAllObjectsInCollection:collection];
+    [self.dbReadWriteConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
+        [transaction removeAllObjectsInCollection:collection];
     }];
 }
 
 - (void)setObject:(id)object forKey:(NSString *)key inCollection:(NSString *)collection {
-    [self.dbConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
-      [transaction setObject:object forKey:key inCollection:collection];
+    [self.dbReadWriteConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
+        [transaction setObject:object forKey:key inCollection:collection];
     }];
 }
 
 - (void)removeObjectForKey:(NSString *)string inCollection:(NSString *)collection {
-    [self.dbConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
+    [self.dbReadWriteConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
         [transaction removeObjectForKey:string inCollection:collection];
     }];
 }
@@ -408,8 +409,8 @@ static NSString *keychainDBPassAccount    = @"TSDatabasePass";
 - (id)objectForKey:(NSString *)key inCollection:(NSString *)collection {
     __block NSString *object;
 
-    [self.dbConnection readWithBlock:^(YapDatabaseReadTransaction *transaction) {
-      object = [transaction objectForKey:key inCollection:collection];
+    [self.dbReadConnection readWithBlock:^(YapDatabaseReadTransaction *transaction) {
+        object = [transaction objectForKey:key inCollection:collection];
     }];
 
     return object;
@@ -419,8 +420,8 @@ static NSString *keychainDBPassAccount    = @"TSDatabasePass";
 {
     __block NSDictionary *object;
 
-    [self.dbConnection readWithBlock:^(YapDatabaseReadTransaction *transaction) {
-      object = [transaction objectForKey:key inCollection:collection];
+    [self.dbReadConnection readWithBlock:^(YapDatabaseReadTransaction *transaction) {
+        object = [transaction objectForKey:key inCollection:collection];
     }];
 
     return object;
@@ -479,7 +480,7 @@ static NSString *keychainDBPassAccount    = @"TSDatabasePass";
 - (int)incrementIntForKey:(NSString *)key inCollection:(NSString *)collection
 {
     __block int value = 0;
-    [self.dbConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
+    [self.dbReadWriteConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
         value = [[transaction objectForKey:key inCollection:collection] intValue];
         value++;
         [transaction setObject:@(value) forKey:key inCollection:collection];
@@ -503,11 +504,11 @@ static NSString *keychainDBPassAccount    = @"TSDatabasePass";
 }
 
 - (void)deleteThreadsAndMessages {
-    [self.dbConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
-      [transaction removeAllObjectsInCollection:[TSThread collection]];
-      [transaction removeAllObjectsInCollection:[SignalRecipient collection]];
-      [transaction removeAllObjectsInCollection:[TSInteraction collection]];
-      [transaction removeAllObjectsInCollection:[TSAttachment collection]];
+    [self.dbReadWriteConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
+        [transaction removeAllObjectsInCollection:[TSThread collection]];
+        [transaction removeAllObjectsInCollection:[SignalRecipient collection]];
+        [transaction removeAllObjectsInCollection:[TSInteraction collection]];
+        [transaction removeAllObjectsInCollection:[TSAttachment collection]];
     }];
     [TSAttachmentStream deleteAttachments];
 }
@@ -529,7 +530,8 @@ static NSString *keychainDBPassAccount    = @"TSDatabasePass";
 - (void)resetSignalStorage
 {
     self.database = nil;
-    _dbConnection = nil;
+    _dbReadConnection = nil;
+    _dbReadWriteConnection = nil;
 
     [self deletePasswordFromKeychain];
 

src/Storage/TSYapDatabaseObject.h

@@ -58,10 +58,12 @@
                                        usingBlock:(void (^)(id object, BOOL *stop))block;
 
 /**
- * @return A shared database connection.
+ * @return Shared database connections for reading and writing.
  */
-- (YapDatabaseConnection *)dbConnection;
-+ (YapDatabaseConnection *)dbConnection;
+- (YapDatabaseConnection *)dbReadConnection;
++ (YapDatabaseConnection *)dbReadConnection;
+- (YapDatabaseConnection *)dbReadWriteConnection;
++ (YapDatabaseConnection *)dbReadWriteConnection;
 
 - (TSStorageManager *)storageManager;
 + (TSStorageManager *)storageManager;

src/Storage/TSYapDatabaseObject.m

@@ -1,5 +1,6 @@
-//  Created by Frederic Jacobs on 16/11/14.
-//  Copyright (c) 2014 Open Whisper Systems. All rights reserved.
+//
+//  Copyright (c) 2017 Open Whisper Systems. All rights reserved.
+//
 
 #import "TSYapDatabaseObject.h"
 #import "TSStorageManager.h"
@@ -31,7 +32,7 @@
 
 - (void)save
 {
-    [[self dbConnection] readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
+    [[self dbReadWriteConnection] readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
         [self saveWithTransaction:transaction];
     }];
 }
@@ -43,7 +44,7 @@
 
 - (void)touch
 {
-    [[self dbConnection] readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
+    [[self dbReadWriteConnection] readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
         [self touchWithTransaction:transaction];
     }];
 }
@@ -55,14 +56,19 @@
 
 - (void)remove
 {
-    [[self dbConnection] readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
+    [[self dbReadWriteConnection] readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
         [self removeWithTransaction:transaction];
     }];
 }
 
-- (YapDatabaseConnection *)dbConnection
+- (YapDatabaseConnection *)dbReadConnection
 {
-    return [[self class] dbConnection];
+    return [[self class] dbReadConnection];
+}
+
+- (YapDatabaseConnection *)dbReadWriteConnection
+{
+    return [[self class] dbReadWriteConnection];
 }
 
 - (TSStorageManager *)storageManager
@@ -72,9 +78,19 @@
 
 #pragma mark Class Methods
 
-+ (YapDatabaseConnection *)dbConnection
++ (YapDatabaseConnection *)dbReadConnection
+{
+    // We use TSStorageManager's dbReadWriteConnection (not its dbReadConnection)
+    // for consistency, since we tend to [TSYapDatabaseObject save] and want to
+    // write to the same connection we read from.  To get true consistency, we'd
+    // want to update entities by reading & writing from within the same
+    // transaction, but that'll be a big refactor.
+    return [self storageManager].dbReadWriteConnection;
+}
+
++ (YapDatabaseConnection *)dbReadWriteConnection
 {
-    return [self storageManager].dbConnection;
+    return [self storageManager].dbReadWriteConnection;
 }
 
 + (TSStorageManager *)storageManager
@@ -90,7 +106,7 @@
 + (NSUInteger)numberOfKeysInCollection
 {
     __block NSUInteger count;
-    [[self dbConnection] readWithBlock:^(YapDatabaseReadTransaction *transaction) {
+    [[self dbReadConnection] readWithBlock:^(YapDatabaseReadTransaction *transaction) {
         count = [self numberOfKeysInCollectionWithTransaction:transaction];
     }];
     return count;
@@ -112,7 +128,7 @@
 
 + (void)enumerateCollectionObjectsUsingBlock:(void (^)(id object, BOOL *stop))block
 {
-    [[self dbConnection] readWithBlock:^(YapDatabaseReadTransaction *transaction) {
+    [[self dbReadConnection] readWithBlock:^(YapDatabaseReadTransaction *transaction) {
         [self enumerateCollectionObjectsWithTransaction:transaction usingBlock:block];
     }];
 }
@@ -131,7 +147,7 @@
 
 + (void)removeAllObjectsInCollection
 {
-    [[self dbConnection] readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
+    [[self dbReadWriteConnection] readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
         [transaction removeAllObjectsInCollection:[self collection]];
     }];
 }
@@ -144,7 +160,7 @@
 + (instancetype)fetchObjectWithUniqueID:(NSString *)uniqueID
 {
     __block id object;
-    [[self dbConnection] readWithBlock:^(YapDatabaseReadTransaction *transaction) {
+    [[self dbReadConnection] readWithBlock:^(YapDatabaseReadTransaction *transaction) {
         object = [transaction objectForKey:uniqueID inCollection:[self collection]];
     }];
     return object;