Apply assert to ensure singletons are only created once.

// FREEBIE

src/Account/TSAccountManager.h

@@ -1,9 +1,5 @@
 //
-//  TSAccountManagement.h
-//  TextSecureKit
-//
-//  Created by Frederic Jacobs on 27/10/14.
-//  Copyright (c) 2014 Open Whisper Systems. All rights reserved.
+//  Copyright (c) 2017 Open Whisper Systems. All rights reserved.
 //
 
 #import <Foundation/Foundation.h>
@@ -21,6 +17,8 @@ static NSString *const TSRegistrationErrorUserInfoHTTPStatus = @"TSHTTPStatus";
 
 #pragma mark - Initializers
 
+- (instancetype)init NS_UNAVAILABLE;
+
 - (instancetype)initWithNetworkManager:(TSNetworkManager *)networkManager
                         storageManager:(TSStorageManager *)storageManager;
 

src/Account/TSAccountManager.m

@@ -35,6 +35,8 @@ NS_ASSUME_NONNULL_BEGIN
     _networkManager = networkManager;
     _storageManager = storageManager;
 
+    OWSSingletonAssert();
+
     return self;
 }
 

src/Account/TSPrivacyPreferences.h

@@ -1,5 +1,6 @@
-//  Created by Michael Kirk on 11/7/16.
-//  Copyright © 2016 Open Whisper Systems. All rights reserved.
+//
+//  Copyright (c) 2017 Open Whisper Systems. All rights reserved.
+//
 
 #import "TSYapDatabaseObject.h"
 
@@ -7,6 +8,8 @@ NS_ASSUME_NONNULL_BEGIN
 
 @interface TSPrivacyPreferences : TSYapDatabaseObject
 
+- (instancetype)init NS_UNAVAILABLE;
+
 + (instancetype)sharedInstance;
 
 @property BOOL shouldBlockOnIdentityChange;

src/Account/TSPrivacyPreferences.m

@@ -1,5 +1,6 @@
-//  Created by Michael Kirk on 11/7/16.
-//  Copyright © 2016 Open Whisper Systems. All rights reserved.
+//
+//  Copyright (c) 2017 Open Whisper Systems. All rights reserved.
+//
 
 #import "TSPrivacyPreferences.h"
 
@@ -37,6 +38,8 @@ NSString *const TSPrivacyPreferencesSingletonKey = @"TSPrivacyPreferences";
 
     _shouldBlockOnIdentityChange = shouldBlockOnIdentityChange;
 
+    OWSSingletonAssert();
+
     return self;
 }
 

src/Contacts/ContactsUpdater.m

@@ -25,6 +25,19 @@ NS_ASSUME_NONNULL_BEGIN
     return sharedInstance;
 }
 
+
+- (instancetype)init
+{
+    self = [super init];
+    if (!self) {
+        return self;
+    }
+
+    OWSSingletonAssert();
+
+    return self;
+}
+
 - (nullable SignalRecipient *)synchronousLookup:(NSString *)identifier error:(NSError **)error
 {
     dispatch_semaphore_t sema = dispatch_semaphore_create(0);

src/Contacts/PhoneNumberUtil.m

@@ -23,6 +23,8 @@
 
     if (self) {
         _nbPhoneNumberUtil = [[NBPhoneNumberUtil alloc] init];
+
+        OWSSingletonAssert();
     }
 
     return self;

src/Messages/OWSMessageSender.h

@@ -1,5 +1,6 @@
-//  Created by Michael Kirk on 10/7/16.
-//  Copyright © 2016 Open Whisper Systems. All rights reserved.
+//
+//  Copyright (c) 2017 Open Whisper Systems. All rights reserved.
+//
 
 NS_ASSUME_NONNULL_BEGIN
 
@@ -23,6 +24,8 @@ NS_SWIFT_NAME(MessageSender)
     ContactsUpdater *_contactsUpdater;
 }
 
+- (instancetype)init NS_UNAVAILABLE;
+
 - (instancetype)initWithNetworkManager:(TSNetworkManager *)networkManager
                         storageManager:(TSStorageManager *)storageManager
                        contactsManager:(id<ContactsManagerProtocol>)contactsManager

src/Messages/OWSMessageSender.m

@@ -288,6 +288,8 @@ NSString *const OWSMessageSenderRateLimitedException = @"RateLimitedException";
     _dbConnection = storageManager.newDatabaseConnection;
     _disappearingMessagesJob = [[OWSDisappearingMessagesJob alloc] initWithStorageManager:storageManager];
 
+    OWSSingletonAssert();
+
     return self;
 }
 

src/Network/API/TSNetworkManager.h

@@ -28,6 +28,8 @@ NS_ASSUME_NONNULL_BEGIN
 
 @interface TSNetworkManager : NSObject
 
+- (instancetype)init NS_UNAVAILABLE;
+
 + (id)sharedManager;
 
 - (void)makeRequest:(TSRequest *)request

src/Network/API/TSNetworkManager.m

@@ -43,6 +43,8 @@ typedef void (^failureBlock)(NSURLSessionDataTask *task, NSError *error);
 
     _signalService = signalService;
 
+    OWSSingletonAssert();
+
     return self;
 }