Use attachment pointers to restore attachments from backup.

Signal/src/util/Backup/OWSBackup.m

@@ -618,6 +618,11 @@ NS_ASSUME_NONNULL_BEGIN
         return completion(NO);
     }
 
+    if (![OWSFileSystem deleteFileIfExists:attachmentFilePath]) {
+        OWSLogError(@"Couldn't delete exist file at attachment path.");
+        return completion(NO);
+    }
+
     NSError *error;
     BOOL success =
         [NSFileManager.defaultManager moveItemAtPath:decryptedFilePath toPath:attachmentFilePath error:&error];

Signal/src/util/Backup/OWSBackupExportJob.m

@@ -507,6 +507,17 @@ NS_ASSUME_NONNULL_BEGIN
                                                   TSYapDatabaseObject *entity = object;
                                                   count++;
 
+                                                  if ([entity isKindOfClass:[TSAttachmentStream class]]) {
+                                                      // Convert attachment streams to pointers,
+                                                      // since we'll need to restore them.
+                                                      TSAttachmentStream *attachmentStream
+                                                          = (TSAttachmentStream *)entity;
+                                                      TSAttachmentPointer *attachmentPointer =
+                                                          [[TSAttachmentPointer alloc]
+                                                              initForRestoreWithAttachmentStream:attachmentStream];
+                                                      entity = attachmentPointer;
+                                                  }
+
                                                   if (![exportStream writeObject:entity entityType:entityType]) {
                                                       *stop = YES;
                                                       aborted = YES;
@@ -536,6 +547,7 @@ NS_ASSUME_NONNULL_BEGIN
             [TSAttachment class],
             ^(id object) {
                 if (![object isKindOfClass:[TSAttachmentStream class]]) {
+                    // No need to backup the contents of attachment pointers.
                     return NO;
                 }
                 TSAttachmentStream *attachmentStream = object;

SignalServiceKit/src/Messages/Attachments/TSAttachment.h

@@ -6,6 +6,7 @@
 
 NS_ASSUME_NONNULL_BEGIN
 
+@class TSAttachmentPointer;
 @class TSMessage;
 
 typedef NS_ENUM(NSUInteger, TSAttachmentType) {
@@ -64,10 +65,11 @@ typedef NS_ENUM(NSUInteger, TSAttachmentType) {
 
 // This constructor is used for new instances of TSAttachmentPointer,
 // i.e. undownloaded restoring attachments.
-- (instancetype)initWithContentType:(NSString *)contentType
-                     sourceFilename:(nullable NSString *)sourceFilename
-                            caption:(nullable NSString *)caption
-                     albumMessageId:(nullable NSString *)albumMessageId;
+- (instancetype)initWithUniqueId:(NSString *)uniqueId
+                     contentType:(NSString *)contentType
+                  sourceFilename:(nullable NSString *)sourceFilename
+                         caption:(nullable NSString *)caption
+                  albumMessageId:(nullable NSString *)albumMessageId;
 
 // This constructor is used for new instances of TSAttachmentStream
 // that represent new, un-uploaded outgoing attachments.
@@ -79,7 +81,7 @@ typedef NS_ENUM(NSUInteger, TSAttachmentType) {
 
 // This constructor is used for new instances of TSAttachmentStream
 // that represent downloaded incoming attachments.
-- (instancetype)initWithPointer:(TSAttachment *)pointer;
+- (instancetype)initWithPointer:(TSAttachmentPointer *)pointer;
 
 - (nullable instancetype)initWithCoder:(NSCoder *)coder;
 

SignalServiceKit/src/Messages/Attachments/TSAttachment.m

@@ -4,6 +4,7 @@
 
 #import "TSAttachment.h"
 #import "MIMETypeUtil.h"
+#import "TSAttachmentPointer.h"
 #import "TSMessage.h"
 #import <SignalCoreKit/NSString+SSK.h>
 #import <SignalCoreKit/iOSVersions.h>
@@ -67,11 +68,13 @@ NSUInteger const TSAttachmentSchemaVersion = 4;
 
 // This constructor is used for new instances of TSAttachmentPointer,
 // i.e. undownloaded restoring attachments.
-- (instancetype)initWithContentType:(NSString *)contentType
-                     sourceFilename:(nullable NSString *)sourceFilename
-                            caption:(nullable NSString *)caption
-                     albumMessageId:(nullable NSString *)albumMessageId
+- (instancetype)initWithUniqueId:(NSString *)uniqueId
+                     contentType:(NSString *)contentType
+                  sourceFilename:(nullable NSString *)sourceFilename
+                         caption:(nullable NSString *)caption
+                  albumMessageId:(nullable NSString *)albumMessageId
 {
+    OWSAssertDebug(uniqueId.length > 0);
     if (contentType.length < 1) {
         OWSLogWarn(@"incoming attachment has invalid content type");
 
@@ -79,7 +82,8 @@ NSUInteger const TSAttachmentSchemaVersion = 4;
     }
     OWSAssertDebug(contentType.length > 0);
 
-    self = [super init];
+    // Once saved, this AttachmentStream will replace the AttachmentPointer in the attachments collection.
+    self = [super initWithUniqueId:uniqueId];
     if (!self) {
         return self;
     }
@@ -128,13 +132,15 @@ NSUInteger const TSAttachmentSchemaVersion = 4;
 
 // This constructor is used for new instances of TSAttachmentStream
 // that represent downloaded incoming attachments.
-- (instancetype)initWithPointer:(TSAttachment *)pointer
+- (instancetype)initWithPointer:(TSAttachmentPointer *)pointer
 {
-    OWSAssertDebug(pointer.serverId > 0);
-    OWSAssertDebug(pointer.encryptionKey.length > 0);
-    if (pointer.byteCount <= 0) {
-        // This will fail with legacy iOS clients which don't upload attachment size.
-        OWSLogWarn(@"Missing pointer.byteCount for attachment with serverId: %lld", pointer.serverId);
+    if (!pointer.lazyRestoreFragment) {
+        OWSAssertDebug(pointer.serverId > 0);
+        OWSAssertDebug(pointer.encryptionKey.length > 0);
+        if (pointer.byteCount <= 0) {
+            // This will fail with legacy iOS clients which don't upload attachment size.
+            OWSLogWarn(@"Missing pointer.byteCount for attachment with serverId: %lld", pointer.serverId);
+        }
     }
     OWSAssertDebug(pointer.contentType.length > 0);
 

SignalServiceKit/src/Messages/Attachments/TSAttachmentPointer.h

@@ -8,6 +8,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 @class OWSBackupFragment;
 @class SSKProtoAttachmentPointer;
+@class TSAttachmentStream;
 @class TSMessage;
 
 typedef NS_ENUM(NSUInteger, TSAttachmentPointerType) {
@@ -49,11 +50,7 @@ typedef NS_ENUM(NSUInteger, TSAttachmentPointerState) {
                   albumMessageId:(nullable NSString *)albumMessageId
                   attachmentType:(TSAttachmentType)attachmentType NS_DESIGNATED_INITIALIZER;
 
-- (instancetype)initForRestoreWithContentType:(NSString *)contentType
-                               sourceFilename:(nullable NSString *)sourceFilename
-                                      caption:(nullable NSString *)caption
-                               albumMessageId:(nullable NSString *)albumMessageId
-                               attachmentType:(TSAttachmentType)attachmentType NS_DESIGNATED_INITIALIZER;
+- (instancetype)initForRestoreWithAttachmentStream:(TSAttachmentStream *)attachmentStream NS_DESIGNATED_INITIALIZER;
 
 + (nullable TSAttachmentPointer *)attachmentPointerFromProto:(SSKProtoAttachmentPointer *)attachmentProto
                                                 albumMessage:(nullable TSMessage *)message;

SignalServiceKit/src/Messages/Attachments/TSAttachmentPointer.m

@@ -4,6 +4,7 @@
 
 #import "TSAttachmentPointer.h"
 #import "OWSBackupFragment.h"
+#import "TSAttachmentStream.h"
 #import <SignalServiceKit/MimeTypeUtil.h>
 #import <SignalServiceKit/SignalServiceKit-Swift.h>
 #import <YapDatabase/YapDatabase.h>
@@ -71,22 +72,21 @@ NS_ASSUME_NONNULL_BEGIN
     return self;
 }
 
-- (instancetype)initForRestoreWithContentType:(NSString *)contentType
-                               sourceFilename:(nullable NSString *)sourceFilename
-                                      caption:(nullable NSString *)caption
-                               albumMessageId:(nullable NSString *)albumMessageId
-                               attachmentType:(TSAttachmentType)attachmentType
+- (instancetype)initForRestoreWithAttachmentStream:(TSAttachmentStream *)attachmentStream
 {
-    self = [super initWithContentType:contentType
-                       sourceFilename:sourceFilename
-                              caption:caption
-                       albumMessageId:albumMessageId];
+    OWSAssertDebug(attachmentStream);
+
+    self = [super initWithUniqueId:attachmentStream.uniqueId
+                       contentType:attachmentStream.contentType
+                    sourceFilename:attachmentStream.sourceFilename
+                           caption:attachmentStream.caption
+                    albumMessageId:attachmentStream.albumMessageId];
     if (!self) {
         return self;
     }
 
     _state = TSAttachmentPointerStateEnqueued;
-    self.attachmentType = attachmentType;
+    self.attachmentType = attachmentStream.attachmentType;
     _pointerType = TSAttachmentPointerTypeRestoring;
 
     return self;

SignalServiceKit/src/Messages/OWSMessageSender.m

@@ -566,7 +566,7 @@ NSString *const OWSMessageSenderRateLimitedException = @"RateLimitedException";
         }
     } else {
         // Neither a group nor contact thread? This should never happen.
-        OWSFailDebug(@"Unknown message type: %@", [message class]);
+        OWSLogError(@"Unknown message type: %@", [message class]);
         NSError *error = OWSErrorMakeFailedToSendOutgoingMessageError();
         [error setIsRetryable:NO];
         *errorHandle = error;