Improve the robustness of the migration logic.

Signal/src/AppDelegate.m

@@ -230,35 +230,64 @@ static NSString *const kURLHostVerifyPrefix             = @"verify";
 
 - (BOOL)ensureIsReadyForAppExtensions
 {
+    // Given how sensitive this migration is, we verbosely
+    // log the contents of all involved paths before and after.
+    //
+    // TODO: Remove this logging once we have high confidence
+    // in our migration logic.
+    NSArray<NSString *> *paths = @[
+        TSStorageManager.legacyDatabaseFilePath,
+        TSStorageManager.legacyDatabaseFilePath_SHM,
+        TSStorageManager.legacyDatabaseFilePath_WAL,
+        TSStorageManager.sharedDataDatabaseFilePath,
+        TSStorageManager.sharedDataDatabaseFilePath_SHM,
+        TSStorageManager.sharedDataDatabaseFilePath_WAL,
+    ];
+    NSFileManager *fileManager = [NSFileManager defaultManager];
+    for (NSString *path in paths) {
+        if ([fileManager fileExistsAtPath:path]) {
+            DDLogInfo(@"%@ storage file: %@, %@", self.logTag, path, [OWSFileSystem fileSizeOfPath:path]);
+        }
+    }
+
     if ([OWSPreferences isReadyForAppExtensions]) {
         return YES;
     }
 
     if ([NSFileManager.defaultManager fileExistsAtPath:TSStorageManager.legacyDatabaseFilePath]) {
-        DDLogInfo(@"%@ Database file size: %@",
+        DDLogInfo(@"%@ Legacy Database file size: %@",
             self.logTag,
             [OWSFileSystem fileSizeOfPath:TSStorageManager.legacyDatabaseFilePath]);
-        DDLogInfo(@"%@ \t SHM file size: %@",
+        DDLogInfo(@"%@ \t Legacy SHM file size: %@",
             self.logTag,
             [OWSFileSystem fileSizeOfPath:TSStorageManager.legacyDatabaseFilePath_SHM]);
-        DDLogInfo(@"%@ \t WAL file size: %@",
+        DDLogInfo(@"%@ \t Legacy WAL file size: %@",
             self.logTag,
             [OWSFileSystem fileSizeOfPath:TSStorageManager.legacyDatabaseFilePath_WAL]);
     }
 
     NSError *_Nullable error = [self convertDatabaseIfNecessary];
+
+    if (!error) {
+        [NSUserDefaults migrateToSharedUserDefaults];
+    }
+
+    if (!error) {
+        error = [TSStorageManager migrateToSharedData];
+    }
+    if (!error) {
+        error = [OWSProfileManager migrateToSharedData];
+    }
+    if (!error) {
+        error = [TSAttachmentStream migrateToSharedData];
+    }
+
     if (error) {
         OWSFail(@"%@ database conversion failed: %@", self.logTag, error);
         [self showLaunchFailureUI:error];
         return NO;
     }
 
-    [NSUserDefaults migrateToSharedUserDefaults];
-
-    [TSStorageManager migrateToSharedData];
-    [OWSProfileManager migrateToSharedData];
-    [TSAttachmentStream migrateToSharedData];
-
     return YES;
 }
 
@@ -304,6 +333,8 @@ static NSString *const kURLHostVerifyPrefix             = @"verify";
 
 - (nullable NSError *)convertDatabaseIfNecessary
 {
+    DDLogInfo(@"%@ %s", self.logTag, __PRETTY_FUNCTION__);
+
     NSString *databaseFilePath = [TSStorageManager legacyDatabaseFilePath];
     if (![[NSFileManager defaultManager] fileExistsAtPath:databaseFilePath]) {
         DDLogVerbose(@"%@ no legacy database file found", self.logTag);

SignalMessaging/profiles/OWSProfileManager.h

@@ -1,5 +1,5 @@
 //
-//  Copyright (c) 2017 Open Whisper Systems. All rights reserved.
+//  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
 //
 
 #import <SignalServiceKit/ProfileManagerProtocol.h>
@@ -24,7 +24,7 @@ extern const NSUInteger kOWSProfileManager_MaxAvatarDiameter;
 
 - (void)resetProfileStorage;
 
-+ (void)migrateToSharedData;
++ (nullable NSError *)migrateToSharedData;
 
 #pragma mark - Local Profile
 

SignalMessaging/profiles/OWSProfileManager.m

@@ -1113,9 +1113,11 @@ const NSUInteger kOWSProfileManager_MaxAvatarDiameter = 640;
     return [[OWSFileSystem appSharedDataDirectoryPath] stringByAppendingPathComponent:@"ProfileAvatars"];
 }
 
-+ (void)migrateToSharedData
++ (nullable NSError *)migrateToSharedData
 {
-    [OWSFileSystem moveAppFilePath:self.legacyProfileAvatarsDirPath
+    DDLogInfo(@"%@ %s", self.logTag, __PRETTY_FUNCTION__);
+
+    return [OWSFileSystem moveAppFilePath:self.legacyProfileAvatarsDirPath
                        sharedDataFilePath:self.sharedDataProfileAvatarsDirPath
                             exceptionName:@"ProfileManagerCouldNotMigrateProfileDirectory"];
 }

SignalServiceKit/src/Messages/Attachments/TSAttachmentStream.h

@@ -58,7 +58,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (CGFloat)audioDurationSeconds;
 
-+ (void)migrateToSharedData;
++ (nullable NSError *)migrateToSharedData;
 
 @end
 

SignalServiceKit/src/Messages/Attachments/TSAttachmentStream.m

@@ -194,9 +194,11 @@ NS_ASSUME_NONNULL_BEGIN
     return [[OWSFileSystem appSharedDataDirectoryPath] stringByAppendingPathComponent:@"Attachments"];
 }
 
-+ (void)migrateToSharedData
++ (nullable NSError *)migrateToSharedData
 {
-    [OWSFileSystem moveAppFilePath:self.legacyAttachmentsDirPath
+    DDLogInfo(@"%@ %s", self.logTag, __PRETTY_FUNCTION__);
+
+    return [OWSFileSystem moveAppFilePath:self.legacyAttachmentsDirPath
                        sharedDataFilePath:self.sharedDataAttachmentsDirPath
                             exceptionName:@"CouldNotMigrateAttachmentsDirectory"];
 }

SignalServiceKit/src/Storage/TSStorageManager.h

@@ -21,13 +21,16 @@ void runAsyncRegistrationsForStorage(OWSStorage *storage);
 + (YapDatabaseConnection *)dbReadConnection;
 + (YapDatabaseConnection *)dbReadWriteConnection;
 
-+ (void)migrateToSharedData;
++ (nullable NSError *)migrateToSharedData;
 
 + (NSString *)databaseFilePath;
 
 + (NSString *)legacyDatabaseFilePath;
 + (NSString *)legacyDatabaseFilePath_SHM;
 + (NSString *)legacyDatabaseFilePath_WAL;
++ (NSString *)sharedDataDatabaseFilePath;
++ (NSString *)sharedDataDatabaseFilePath_SHM;
++ (NSString *)sharedDataDatabaseFilePath_WAL;
 
 @end
 

SignalServiceKit/src/Storage/TSStorageManager.m

@@ -220,8 +220,10 @@ void runAsyncRegistrationsForStorage(OWSStorage *storage)
     return [self.sharedDataDatabaseDirPath stringByAppendingPathComponent:self.databaseFilename_WAL];
 }
 
-+ (void)migrateToSharedData
++ (nullable NSError *)migrateToSharedData
 {
+    DDLogInfo(@"%@ %s", self.logTag, __PRETTY_FUNCTION__);
+
     // Given how sensitive this migration is, we verbosely
     // log the contents of all involved paths before and after.
     NSArray<NSString *> *paths = @[
@@ -235,7 +237,7 @@ void runAsyncRegistrationsForStorage(OWSStorage *storage)
     NSFileManager *fileManager = [NSFileManager defaultManager];
     for (NSString *path in paths) {
         if ([fileManager fileExistsAtPath:path]) {
-            DDLogInfo(@"%@ migrateToSharedData before %@: %@", self.logTag, path, [OWSFileSystem fileSizeOfPath:path]);
+            DDLogInfo(@"%@ before migrateToSharedData: %@, %@", self.logTag, path, [OWSFileSystem fileSizeOfPath:path]);
         }
     }
 
@@ -252,21 +254,33 @@ void runAsyncRegistrationsForStorage(OWSStorage *storage)
     [OWSFileSystem protectFileOrFolderAtPath:self.legacyDatabaseFilePath_SHM];
     [OWSFileSystem protectFileOrFolderAtPath:self.legacyDatabaseFilePath_WAL];
 
-    [OWSFileSystem moveAppFilePath:self.legacyDatabaseFilePath
+    NSError *_Nullable error = nil;
+    error = [OWSFileSystem moveAppFilePath:self.legacyDatabaseFilePath
                         sharedDataFilePath:self.sharedDataDatabaseFilePath
                              exceptionName:TSStorageManagerExceptionName_CouldNotMoveDatabaseFile];
-    [OWSFileSystem moveAppFilePath:self.legacyDatabaseFilePath_SHM
+    if (error) {
+        return error;
+    }
+    error = [OWSFileSystem moveAppFilePath:self.legacyDatabaseFilePath_SHM
                         sharedDataFilePath:self.sharedDataDatabaseFilePath_SHM
                              exceptionName:TSStorageManagerExceptionName_CouldNotMoveDatabaseFile];
-    [OWSFileSystem moveAppFilePath:self.legacyDatabaseFilePath_WAL
+    if (error) {
+        return error;
+    }
+    error = [OWSFileSystem moveAppFilePath:self.legacyDatabaseFilePath_WAL
                         sharedDataFilePath:self.sharedDataDatabaseFilePath_WAL
                              exceptionName:TSStorageManagerExceptionName_CouldNotMoveDatabaseFile];
+    if (error) {
+        return error;
+    }
 
     for (NSString *path in paths) {
         if ([fileManager fileExistsAtPath:path]) {
-            DDLogInfo(@"%@ migrateToSharedData after %@: %@", self.logTag, path, [OWSFileSystem fileSizeOfPath:path]);
+            DDLogInfo(@"%@ after migrateToSharedData: %@, %@", self.logTag, path, [OWSFileSystem fileSizeOfPath:path]);
         }
     }
+
+    return nil;
 }
 
 + (NSString *)databaseFilePath

SignalServiceKit/src/Util/NSUserDefaults+OWS.m

@@ -2,8 +2,8 @@
 //  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
 //
 
-#import "AppContext.h"
 #import "NSUserDefaults+OWS.h"
+#import "AppContext.h"
 #import "TSConstants.h"
 
 NS_ASSUME_NONNULL_BEGIN
@@ -17,6 +17,8 @@ NS_ASSUME_NONNULL_BEGIN
 
 + (void)migrateToSharedUserDefaults
 {
+    DDLogInfo(@"%@ %s", self.logTag, __PRETTY_FUNCTION__);
+
     NSUserDefaults *appUserDefaults = self.appUserDefaults;
 
     NSDictionary<NSString *, id> *dictionary = [NSUserDefaults standardUserDefaults].dictionaryRepresentation;

SignalServiceKit/src/Util/OWSAsserts.h

@@ -121,6 +121,13 @@ NS_ASSUME_NONNULL_BEGIN
 // This macro is intended for use in Objective-C.
 #define OWSAssertIsOnMainThread() OWSCAssert([NSThread isMainThread])
 
+#define OWSProdLogAndFail(_messageFormat, ...)                                                                         \
+    {                                                                                                                  \
+        DDLogError(_messageFormat, ##__VA_ARGS__);                                                                     \
+        [DDLog flushLog];                                                                                              \
+        OWSFail(_messageFormat, ##__VA_ARGS__);                                                                        \
+    }
+
 // This function is intended for use in Swift.
 void AssertIsOnMainThread(void);
 

SignalServiceKit/src/Util/OWSError.h

@@ -27,7 +27,8 @@ typedef NS_ENUM(NSInteger, OWSErrorCode) {
     OWSErrorCodeContactsUpdaterRateLimit = 777408,
     OWSErrorCodeCouldNotWriteAttachmentData = 777409,
     OWSErrorCodeMessageDeletedBeforeSent = 777410,
-    OWSErrorCodeDatabaseConversionFatalError = 777411
+    OWSErrorCodeDatabaseConversionFatalError = 777411,
+    OWSErrorCodeMoveFileToSharedDataContainerError = 777412
 };
 
 extern NSString *const OWSErrorRecipientIdentifierKey;

SignalServiceKit/src/Util/OWSFileSystem.h

@@ -17,7 +17,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 + (NSString *)cachesDirectoryPath;
 
-+ (void)moveAppFilePath:(NSString *)oldFilePath
++ (nullable NSError *)moveAppFilePath:(NSString *)oldFilePath
                    sharedDataFilePath:(NSString *)newFilePath
                         exceptionName:(NSString *)exceptionName;
 

SignalServiceKit/src/Util/OWSFileSystem.m

@@ -3,6 +3,7 @@
 //
 
 #import "OWSFileSystem.h"
+#import "OWSError.h"
 #import "TSConstants.h"
 
 NS_ASSUME_NONNULL_BEGIN
@@ -107,23 +108,47 @@ NS_ASSUME_NONNULL_BEGIN
     return paths[0];
 }
 
-+ (void)moveAppFilePath:(NSString *)oldFilePath
++ (nullable NSError *)moveAppFilePath:(NSString *)oldFilePath
                    sharedDataFilePath:(NSString *)newFilePath
                         exceptionName:(NSString *)exceptionName
 {
     NSFileManager *fileManager = [NSFileManager defaultManager];
     if (![fileManager fileExistsAtPath:oldFilePath]) {
-        return;
+        return nil;
     }
 
     DDLogInfo(@"%@ Moving file or directory from: %@ to: %@", self.logTag, oldFilePath, newFilePath);
 
     if ([fileManager fileExistsAtPath:newFilePath]) {
-        OWSFail(@"%@ Can't move file or directory from: %@ to: %@; destination already exists.",
+        // If a file/directory already exists at the destination,
+        // try to move it "aside" by renaming it with an extension.
+        NSString *legacyFilePath =
+            [[newFilePath stringByAppendingString:@"."] stringByAppendingString:[NSUUID UUID].UUIDString];
+        DDLogInfo(@"%@ Trying to rename pre-existing destination file or directory from: %@ to: %@",
+            self.logTag,
+            newFilePath,
+            legacyFilePath);
+
+        NSError *_Nullable error;
+        BOOL success = [fileManager moveItemAtPath:newFilePath toPath:legacyFilePath error:&error];
+        if (!success || error) {
+            OWSProdLogAndFail(
+                @"%@ Could not move pre-existing destination file or directory from: %@ to: %@, error: %@",
+                self.logTag,
+                newFilePath,
+                legacyFilePath,
+                error);
+            return error;
+        }
+    }
+
+    if ([fileManager fileExistsAtPath:newFilePath]) {
+        OWSProdLogAndFail(@"%@ Can't move file or directory from: %@ to: %@; destination already exists.",
             self.logTag,
             oldFilePath,
             newFilePath);
-        return;
+        return OWSErrorWithCodeDescription(
+            OWSErrorCodeMoveFileToSharedDataContainerError, @"Can't move file; destination already exists.");
     }
     
     NSDate *startDate = [NSDate new];
@@ -131,14 +156,12 @@ NS_ASSUME_NONNULL_BEGIN
     NSError *_Nullable error;
     BOOL success = [fileManager moveItemAtPath:oldFilePath toPath:newFilePath error:&error];
     if (!success || error) {
-        NSString *errorDescription =
+        OWSProdLogAndFail(@"%@ Could not move file or directory from: %@ to: %@, error: %@",
-            [NSString stringWithFormat:@"%@ Could not move file or directory from: %@ to: %@, error: %@",
             self.logTag,
             oldFilePath,
             newFilePath,
-                      error];
+            error);
-        OWSFail(@"%@", errorDescription);
+        return error;
-        OWSRaiseException(exceptionName, @"%@", errorDescription);
     }
 
     DDLogInfo(@"%@ Moved file or directory from: %@ to: %@ in: %f",
@@ -153,6 +176,8 @@ NS_ASSUME_NONNULL_BEGIN
     dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
         [self protectRecursiveContentsAtPath:newFilePath];
     });
+
+    return nil;
 }
 
 + (BOOL)ensureDirectoryExists:(NSString *)dirPath