From d6af5028ca5948da361c31bf007bdf525a8edadb Mon Sep 17 00:00:00 2001
From: Michael Kirk <michael.code@endoftheworl.de>
Date: Fri, 17 Mar 2017 16:49:56 -0400
Subject: [PATCH] Fix receiving attachments from old clients

Protobuf's null-object pattern provides an empty NSData when no digest
is provided rather than nil.

// FREEBIE
---
 src/Messages/Attachments/OWSAttachmentsProcessor.m | 10 +++++++++-
 src/Messages/Attachments/TSAttachmentPointer.h     |  2 +-
 src/Messages/Attachments/TSAttachmentPointer.m     |  3 +--
 3 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/src/Messages/Attachments/OWSAttachmentsProcessor.m b/src/Messages/Attachments/OWSAttachmentsProcessor.m
index 3683e78d4..2d59730df 100644
--- a/src/Messages/Attachments/OWSAttachmentsProcessor.m
+++ b/src/Messages/Attachments/OWSAttachmentsProcessor.m
@@ -63,9 +63,17 @@ NS_ASSUME_NONNULL_BEGIN
     NSMutableArray<NSString *> *supportedAttachmentIds = [NSMutableArray new];
 
     for (OWSSignalServiceProtosAttachmentPointer *attachmentProto in attachmentProtos) {
+
+        OWSAssert(attachmentProto.id != 0);
+        OWSAssert(attachmentProto.key != nil);
+        OWSAssert(attachmentProto.contentType != nil);
+
+        // digest will be empty for old clients.
+        NSData *digest = attachmentProto.hasDigest ? attachmentProto.digest : nil;
+
         TSAttachmentPointer *pointer = [[TSAttachmentPointer alloc] initWithServerId:attachmentProto.id
                                                                                  key:attachmentProto.key
-                                                                              digest:attachmentProto.digest
+                                                                              digest:digest
                                                                          contentType:attachmentProto.contentType
                                                                                relay:relay];
 
diff --git a/src/Messages/Attachments/TSAttachmentPointer.h b/src/Messages/Attachments/TSAttachmentPointer.h
index a96aef9fb..a6a825b5c 100644
--- a/src/Messages/Attachments/TSAttachmentPointer.h
+++ b/src/Messages/Attachments/TSAttachmentPointer.h
@@ -13,7 +13,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (instancetype)initWithServerId:(UInt64)serverId
                              key:(NSData *)key
-                          digest:(NSData *)digest
+                          digest:(nullable NSData *)digest
                      contentType:(NSString *)contentType
                            relay:(NSString *)relay NS_DESIGNATED_INITIALIZER;
 
diff --git a/src/Messages/Attachments/TSAttachmentPointer.m b/src/Messages/Attachments/TSAttachmentPointer.m
index 0010c79c8..40a930830 100644
--- a/src/Messages/Attachments/TSAttachmentPointer.m
+++ b/src/Messages/Attachments/TSAttachmentPointer.m
@@ -10,7 +10,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (instancetype)initWithServerId:(UInt64)serverId
                              key:(NSData *)key
-                          digest:(NSData *)digest
+                          digest:(nullable NSData *)digest
                      contentType:(NSString *)contentType
                            relay:(NSString *)relay
 {
@@ -19,7 +19,6 @@ NS_ASSUME_NONNULL_BEGIN
         return self;
     }
 
-    OWSAssert(digest != nil);
     _digest = digest;
     _failed = NO;
     _downloading = NO;