Merge branch 'charlesmchen/honorAttachmentFilenames'

protobuf/OWSSignalServiceProtos.proto

@@ -39,11 +39,15 @@ message Content {
 message CallMessage {
   message Offer {
     optional uint64 id          = 1;
+	// We've renamed the description field on iOS to avoid
+	// conflicts with [NSObject description].
     optional string sessionDescription = 2;
   }
 
   message Answer {
     optional uint64 id          = 1;
+	// We've renamed the description field on iOS to avoid
+	// conflicts with [NSObject description].
     optional string sessionDescription = 2;
   }
 
@@ -134,14 +138,16 @@ message AttachmentPointer {
   optional uint32  size        = 4;
   optional bytes   thumbnail   = 5;
   optional bytes   digest      = 6;
+  optional string  fileName    = 7;
 }
 
 message GroupContext {
   enum Type {
-    UNKNOWN = 0;
+    UNKNOWN      = 0;
-    UPDATE  = 1;
+    UPDATE       = 1;
-    DELIVER = 2;
+    DELIVER      = 2;
-    QUIT    = 3;
+    QUIT         = 3;
+    REQUEST_INFO = 4;
   }
   optional bytes             id      = 1;
   optional Type              type    = 2;

src/Messages/Attachments/OWSAttachmentsProcessor.m

@@ -75,7 +75,8 @@ NS_ASSUME_NONNULL_BEGIN
                                                                                  key:attachmentProto.key
                                                                               digest:digest
                                                                          contentType:attachmentProto.contentType
-                                                                               relay:relay];
+                                                                               relay:relay
+                                                                            filename:attachmentProto.fileName];
 
         [attachmentIds addObject:pointer.uniqueId];
 

src/Messages/Attachments/TSAttachmentPointer.h

@@ -21,9 +21,11 @@ typedef NS_ENUM(NSUInteger, TSAttachmentPointerState) {
                              key:(NSData *)key
                           digest:(nullable NSData *)digest
                      contentType:(NSString *)contentType
-                           relay:(NSString *)relay NS_DESIGNATED_INITIALIZER;
+                           relay:(NSString *)relay
+                        filename:(nullable NSString *)filename NS_DESIGNATED_INITIALIZER;
 
 @property (nonatomic, readonly) NSString *relay;
+@property (nonatomic, readonly, nullable) NSString *filename;
 @property (atomic) TSAttachmentPointerState state;
 
 // Though now required, `digest` may be null for pre-existing records or from

src/Messages/Attachments/TSAttachmentPointer.m

@@ -30,6 +30,7 @@ NS_ASSUME_NONNULL_BEGIN
                           digest:(nullable NSData *)digest
                      contentType:(NSString *)contentType
                            relay:(NSString *)relay
+                        filename:(nullable NSString *)filename
 {
     self = [super initWithServerId:serverId encryptionKey:key contentType:contentType];
     if (!self) {
@@ -39,6 +40,7 @@ NS_ASSUME_NONNULL_BEGIN
     _digest = digest;
     _state = TSAttachmentPointerStateEnqueued;
     _relay = relay;
+    _filename = filename;
 
     return self;
 }

src/Messages/Attachments/TSAttachmentStream.h

@@ -24,6 +24,8 @@ NS_ASSUME_NONNULL_BEGIN
 // This only applies for attachments being uploaded.
 @property (atomic) BOOL isUploaded;
 
+@property (nonatomic, readonly, nullable) NSString *filename;
+
 #if TARGET_OS_IPHONE
 - (nullable UIImage *)image;
 #endif

src/Messages/Attachments/TSAttachmentStream.m

@@ -42,6 +42,7 @@ NS_ASSUME_NONNULL_BEGIN
     // state, but this constructor is used only for new incoming
     // attachments which don't need to be uploaded.
     _isUploaded = YES;
+    _filename = pointer.filename;
 
     return self;
 }
@@ -115,6 +116,7 @@ NS_ASSUME_NONNULL_BEGIN
 {
     return [MIMETypeUtil filePathForAttachment:self.uniqueId
                                     ofMIMEType:self.contentType
+                                      filename:self.filename
                                       inFolder:[[self class] attachmentsFolder]];
 }
 

src/Messages/DeviceSyncing/OWSSyncContactsMessage.m

@@ -1,4 +1,6 @@
-//  Copyright © 2016 Open Whisper Systems. All rights reserved.
+//
+//  Copyright (c) 2017 Open Whisper Systems. All rights reserved.
+//
 
 #import "OWSSyncContactsMessage.h"
 #import "Contact.h"
@@ -39,7 +41,7 @@ NS_ASSUME_NONNULL_BEGIN
     }
 
     OWSSignalServiceProtosAttachmentPointer *attachmentProto =
-        [self buildAttachmentProtoForAttachmentId:self.attachmentIds[0]];
+        [self buildAttachmentProtoForAttachmentId:self.attachmentIds[0] filename:nil];
 
     OWSSignalServiceProtosSyncMessageContactsBuilder *contactsBuilder =
         [OWSSignalServiceProtosSyncMessageContactsBuilder new];

src/Messages/DeviceSyncing/OWSSyncGroupsMessage.m

@@ -1,4 +1,6 @@
-//  Copyright © 2016 Open Whisper Systems. All rights reserved.
+//
+//  Copyright (c) 2017 Open Whisper Systems. All rights reserved.
+//
 
 #import "OWSSyncGroupsMessage.h"
 #import "NSDate+millisecondTimeStamp.h"
@@ -25,7 +27,7 @@ NS_ASSUME_NONNULL_BEGIN
             (unsigned long)self.attachmentIds.count);
     }
     OWSSignalServiceProtosAttachmentPointer *attachmentProto =
-        [self buildAttachmentProtoForAttachmentId:self.attachmentIds[0]];
+        [self buildAttachmentProtoForAttachmentId:self.attachmentIds[0] filename:nil];
 
     OWSSignalServiceProtosSyncMessageGroupsBuilder *groupsBuilder =
         [OWSSignalServiceProtosSyncMessageGroupsBuilder new];

src/Messages/Interactions/TSMessage.m

@@ -128,7 +128,6 @@ static const NSUInteger OWSMessageSchemaVersion = 3;
     }
 
     if (!_attachmentIds) {
-        // previously allowed nil _attachmentIds
         _attachmentIds = [NSMutableArray new];
     }
 

src/Messages/Interactions/TSOutgoingMessage.h

@@ -57,6 +57,8 @@ typedef NS_ENUM(NSInteger, TSOutgoingMessageState) {
 @property BOOL hasSyncedTranscript;
 @property NSString *customMessage;
 @property (atomic, readonly) NSString *mostRecentFailureText;
+// A map of attachment id-to-filename.
+@property (nonatomic, readonly) NSMutableDictionary<NSString *, NSString *> *attachmentFilenameMap;
 
 /**
  * Whether the message should be serialized as a modern aka Content, or the old style legacy message.
@@ -94,10 +96,14 @@ typedef NS_ENUM(NSInteger, TSOutgoingMessageState) {
  * @param attachmentId
  *   id of an AttachmentStream containing the meta data used when populating the attachment proto
  *
+ * @param filename
+ *   optional filename of the attachment.
+ *
  * @return
  *      An attachment pointer protobuf suitable for including in various container protobuf builders
  */
-- (OWSSignalServiceProtosAttachmentPointer *)buildAttachmentProtoForAttachmentId:(NSString *)attachmentId;
+- (OWSSignalServiceProtosAttachmentPointer *)buildAttachmentProtoForAttachmentId:(NSString *)attachmentId
+                                                                        filename:(nullable NSString *)filename;
 
 @end
 

src/Messages/Interactions/TSOutgoingMessage.m

@@ -15,7 +15,13 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (instancetype)initWithCoder:(NSCoder *)coder
 {
-    return [super initWithCoder:coder];
+    self = [super initWithCoder:coder];
+    if (self) {
+        if (!_attachmentFilenameMap) {
+            _attachmentFilenameMap = [NSMutableDictionary new];
+        }
+    }
+    return self;
 }
 
 - (instancetype)initWithTimestamp:(uint64_t)timestamp
@@ -86,6 +92,7 @@ NS_ASSUME_NONNULL_BEGIN
     } else {
         self.groupMetaMessage = TSGroupMessageNone;
     }
+    _attachmentFilenameMap = [NSMutableDictionary new];
 
     OWSAssert(self.receivedAtDate);
 
@@ -142,7 +149,8 @@ NS_ASSUME_NONNULL_BEGIN
             case TSGroupMessageNew: {
                 if (gThread.groupModel.groupImage != nil && self.attachmentIds.count == 1) {
                     attachmentWasGroupAvatar = YES;
-                    [groupBuilder setAvatar:[self buildAttachmentProtoForAttachmentId:self.attachmentIds[0]]];
+                    [groupBuilder
+                        setAvatar:[self buildAttachmentProtoForAttachmentId:self.attachmentIds[0] filename:nil]];
                 }
 
                 [groupBuilder setMembersArray:gThread.groupModel.groupMemberIds];
@@ -160,7 +168,8 @@ NS_ASSUME_NONNULL_BEGIN
     if (!attachmentWasGroupAvatar) {
         NSMutableArray *attachments = [NSMutableArray new];
         for (NSString *attachmentId in self.attachmentIds) {
-            [attachments addObject:[self buildAttachmentProtoForAttachmentId:attachmentId]];
+            NSString *filename = self.attachmentFilenameMap[attachmentId];
+            [attachments addObject:[self buildAttachmentProtoForAttachmentId:attachmentId filename:filename]];
         }
         [builder setAttachmentsArray:attachments];
     }
@@ -191,7 +200,10 @@ NS_ASSUME_NONNULL_BEGIN
 }
 
 - (OWSSignalServiceProtosAttachmentPointer *)buildAttachmentProtoForAttachmentId:(NSString *)attachmentId
+                                                                        filename:(nullable NSString *)filename
 {
+    OWSAssert(attachmentId.length > 0);
+
     TSAttachment *attachment = [TSAttachmentStream fetchObjectWithUniqueID:attachmentId];
     if (![attachment isKindOfClass:[TSAttachmentStream class]]) {
         DDLogError(@"Unexpected type for attachment builder: %@", attachment);
@@ -202,6 +214,7 @@ NS_ASSUME_NONNULL_BEGIN
     OWSSignalServiceProtosAttachmentPointerBuilder *builder = [OWSSignalServiceProtosAttachmentPointerBuilder new];
     [builder setId:attachmentStream.serverId];
     [builder setContentType:attachmentStream.contentType];
+    [builder setFileName:filename];
     [builder setKey:attachmentStream.encryptionKey];
     [builder setDigest:attachmentStream.digest];
 

src/Messages/OWSCallAnswerMessage.m

@@ -1,5 +1,6 @@
-//  Created by Michael Kirk on 12/1/16.
+//
-//  Copyright © 2016 Open Whisper Systems. All rights reserved.
+//  Copyright (c) 2017 Open Whisper Systems. All rights reserved.
+//
 
 #import "OWSCallAnswerMessage.h"
 #import "OWSSignalServiceProtos.pb.h"

src/Messages/OWSCallOfferMessage.m

@@ -1,5 +1,6 @@
-//  Created by Michael Kirk on 12/1/16.
+//
-//  Copyright © 2016 Open Whisper Systems. All rights reserved.
+//  Copyright (c) 2017 Open Whisper Systems. All rights reserved.
+//
 
 #import "OWSCallOfferMessage.h"
 #import "OWSSignalServiceProtos.pb.h"

src/Messages/OWSMessageSender.h

@@ -55,6 +55,7 @@ NS_SWIFT_NAME(MessageSender)
  */
 - (void)sendAttachmentData:(NSData *)attachmentData
                contentType:(NSString *)contentType
+                  filename:(nullable NSString *)filename
                  inMessage:(TSOutgoingMessage *)outgoingMessage
                    success:(void (^)())successHandler
                    failure:(void (^)(NSError *error))failureHandler;

src/Messages/OWSMessageSender.m

@@ -437,6 +437,7 @@ NSString *const OWSMessageSenderRateLimitedException = @"RateLimitedException";
 
     [self sendAttachmentData:attachmentData
                  contentType:contentType
+                    filename:nil
                    inMessage:message
                      success:successWithDeleteHandler
                      failure:failureWithDeleteHandler];
@@ -444,6 +445,7 @@ NSString *const OWSMessageSenderRateLimitedException = @"RateLimitedException";
 
 - (void)sendAttachmentData:(NSData *)data
                contentType:(NSString *)contentType
+                  filename:(nullable NSString *)filename
                  inMessage:(TSOutgoingMessage *)message
                    success:(void (^)())successHandler
                    failure:(void (^)(NSError *error))failureHandler
@@ -467,6 +469,9 @@ NSString *const OWSMessageSenderRateLimitedException = @"RateLimitedException";
 
         [attachmentStream save];
         [message.attachmentIds addObject:attachmentStream.uniqueId];
+        if (filename) {
+            message.attachmentFilenameMap[attachmentStream.uniqueId] = filename;
+        }
         [message save];
 
         dispatch_async(dispatch_get_main_queue(), ^{

src/Messages/OWSSignalServiceProtos.pb.h

@@ -1,4 +1,6 @@
-// Generated by the protocol buffer compiler.  DO NOT EDIT!
+//
+//  Copyright (c) 2017 Open Whisper Systems. All rights reserved.
+//
 
 #import <ProtocolBuffers/ProtocolBuffers.h>
 
@@ -128,6 +130,7 @@ typedef NS_ENUM(SInt32, OWSSignalServiceProtosGroupContextType) {
   OWSSignalServiceProtosGroupContextTypeUpdate = 1,
   OWSSignalServiceProtosGroupContextTypeDeliver = 2,
   OWSSignalServiceProtosGroupContextTypeQuit = 3,
+  OWSSignalServiceProtosGroupContextTypeRequestInfo = 4,
 };
 
 BOOL OWSSignalServiceProtosGroupContextTypeIsValidValue(OWSSignalServiceProtosGroupContextType value);
@@ -1278,16 +1281,19 @@ NSString *NSStringFromOWSSignalServiceProtosGroupContextType(OWSSignalServicePro
 #define AttachmentPointer_size @"size"
 #define AttachmentPointer_thumbnail @"thumbnail"
 #define AttachmentPointer_digest @"digest"
+#define AttachmentPointer_fileName @"fileName"
 @interface OWSSignalServiceProtosAttachmentPointer : PBGeneratedMessage<GeneratedMessageProtocol> {
 @private
   BOOL hasId_:1;
   BOOL hasContentType_:1;
+  BOOL hasFileName_:1;
   BOOL hasKey_:1;
   BOOL hasThumbnail_:1;
   BOOL hasDigest_:1;
   BOOL hasSize_:1;
   UInt64 id;
   NSString* contentType;
+  NSString* fileName;
   NSData* key;
   NSData* thumbnail;
   NSData* digest;
@@ -1299,12 +1305,14 @@ NSString *NSStringFromOWSSignalServiceProtosGroupContextType(OWSSignalServicePro
 - (BOOL) hasSize;
 - (BOOL) hasThumbnail;
 - (BOOL) hasDigest;
+- (BOOL) hasFileName;
 @property (readonly) UInt64 id;
 @property (readonly, strong) NSString* contentType;
 @property (readonly, strong) NSData* key;
 @property (readonly) UInt32 size;
 @property (readonly, strong) NSData* thumbnail;
 @property (readonly, strong) NSData* digest;
+@property (readonly, strong) NSString* fileName;
 
 + (instancetype) defaultInstance;
 - (instancetype) defaultInstance;
@@ -1370,6 +1378,11 @@ NSString *NSStringFromOWSSignalServiceProtosGroupContextType(OWSSignalServicePro
 - (NSData*) digest;
 - (OWSSignalServiceProtosAttachmentPointerBuilder*) setDigest:(NSData*) value;
 - (OWSSignalServiceProtosAttachmentPointerBuilder*) clearDigest;
+
+- (BOOL) hasFileName;
+- (NSString*) fileName;
+- (OWSSignalServiceProtosAttachmentPointerBuilder*) setFileName:(NSString*) value;
+- (OWSSignalServiceProtosAttachmentPointerBuilder*) clearFileName;
 @end
 
 #define GroupContext_id @"id"

src/Messages/OWSSignalServiceProtos.pb.m

@@ -1,4 +1,6 @@
-// Generated by the protocol buffer compiler.  DO NOT EDIT!
+//
+//  Copyright (c) 2017 Open Whisper Systems. All rights reserved.
+//
 
 #import "OWSSignalServiceProtos.pb.h"
 // @@protoc_insertion_point(imports)
@@ -5320,6 +5322,7 @@ static OWSSignalServiceProtosSyncMessageRead* defaultOWSSignalServiceProtosSyncM
 @property UInt32 size;
 @property (strong) NSData* thumbnail;
 @property (strong) NSData* digest;
+@property (strong) NSString* fileName;
 @end
 
 @implementation OWSSignalServiceProtosAttachmentPointer
@@ -5366,6 +5369,13 @@ static OWSSignalServiceProtosSyncMessageRead* defaultOWSSignalServiceProtosSyncM
   hasDigest_ = !!_value_;
 }
 @synthesize digest;
+- (BOOL) hasFileName {
+  return !!hasFileName_;
+}
+- (void) setHasFileName:(BOOL) _value_ {
+  hasFileName_ = !!_value_;
+}
+@synthesize fileName;
 - (instancetype) init {
   if ((self = [super init])) {
     self.id = 0L;
@@ -5374,6 +5384,7 @@ static OWSSignalServiceProtosSyncMessageRead* defaultOWSSignalServiceProtosSyncM
     self.size = 0;
     self.thumbnail = [NSData data];
     self.digest = [NSData data];
+    self.fileName = @"";
   }
   return self;
 }
@@ -5411,6 +5422,9 @@ static OWSSignalServiceProtosAttachmentPointer* defaultOWSSignalServiceProtosAtt
   if (self.hasDigest) {
     [output writeData:6 value:self.digest];
   }
+  if (self.hasFileName) {
+    [output writeString:7 value:self.fileName];
+  }
   [self.unknownFields writeToCodedOutputStream:output];
 }
 - (SInt32) serializedSize {
@@ -5438,6 +5452,9 @@ static OWSSignalServiceProtosAttachmentPointer* defaultOWSSignalServiceProtosAtt
   if (self.hasDigest) {
     size_ += computeDataSize(6, self.digest);
   }
+  if (self.hasFileName) {
+    size_ += computeStringSize(7, self.fileName);
+  }
   size_ += self.unknownFields.serializedSize;
   memoizedSerializedSize = size_;
   return size_;
@@ -5491,6 +5508,9 @@ static OWSSignalServiceProtosAttachmentPointer* defaultOWSSignalServiceProtosAtt
   if (self.hasDigest) {
     [output appendFormat:@"%@%@: %@\n", indent, @"digest", self.digest];
   }
+  if (self.hasFileName) {
+    [output appendFormat:@"%@%@: %@\n", indent, @"fileName", self.fileName];
+  }
   [self.unknownFields writeDescriptionTo:output withIndent:indent];
 }
 - (void) storeInDictionary:(NSMutableDictionary *)dictionary {
@@ -5512,6 +5532,9 @@ static OWSSignalServiceProtosAttachmentPointer* defaultOWSSignalServiceProtosAtt
   if (self.hasDigest) {
     [dictionary setObject: self.digest forKey: @"digest"];
   }
+  if (self.hasFileName) {
+    [dictionary setObject: self.fileName forKey: @"fileName"];
+  }
   [self.unknownFields storeInDictionary:dictionary];
 }
 - (BOOL) isEqual:(id)other {
@@ -5535,6 +5558,8 @@ static OWSSignalServiceProtosAttachmentPointer* defaultOWSSignalServiceProtosAtt
       (!self.hasThumbnail || [self.thumbnail isEqual:otherMessage.thumbnail]) &&
       self.hasDigest == otherMessage.hasDigest &&
       (!self.hasDigest || [self.digest isEqual:otherMessage.digest]) &&
+      self.hasFileName == otherMessage.hasFileName &&
+      (!self.hasFileName || [self.fileName isEqual:otherMessage.fileName]) &&
       (self.unknownFields == otherMessage.unknownFields || (self.unknownFields != nil && [self.unknownFields isEqual:otherMessage.unknownFields]));
 }
 - (NSUInteger) hash {
@@ -5557,6 +5582,9 @@ static OWSSignalServiceProtosAttachmentPointer* defaultOWSSignalServiceProtosAtt
   if (self.hasDigest) {
     hashCode = hashCode * 31 + [self.digest hash];
   }
+  if (self.hasFileName) {
+    hashCode = hashCode * 31 + [self.fileName hash];
+  }
   hashCode = hashCode * 31 + [self.unknownFields hash];
   return hashCode;
 }
@@ -5618,6 +5646,9 @@ static OWSSignalServiceProtosAttachmentPointer* defaultOWSSignalServiceProtosAtt
   if (other.hasDigest) {
     [self setDigest:other.digest];
   }
+  if (other.hasFileName) {
+    [self setFileName:other.fileName];
+  }
   [self mergeUnknownFields:other.unknownFields];
   return self;
 }
@@ -5663,6 +5694,10 @@ static OWSSignalServiceProtosAttachmentPointer* defaultOWSSignalServiceProtosAtt
         [self setDigest:[input readData]];
         break;
       }
+      case 58: {
+        [self setFileName:[input readString]];
+        break;
+      }
     }
   }
 }
@@ -5762,6 +5797,22 @@ static OWSSignalServiceProtosAttachmentPointer* defaultOWSSignalServiceProtosAtt
   resultAttachmentPointer.digest = [NSData data];
   return self;
 }
+- (BOOL) hasFileName {
+  return resultAttachmentPointer.hasFileName;
+}
+- (NSString*) fileName {
+  return resultAttachmentPointer.fileName;
+}
+- (OWSSignalServiceProtosAttachmentPointerBuilder*) setFileName:(NSString*) value {
+  resultAttachmentPointer.hasFileName = YES;
+  resultAttachmentPointer.fileName = value;
+  return self;
+}
+- (OWSSignalServiceProtosAttachmentPointerBuilder*) clearFileName {
+  resultAttachmentPointer.hasFileName = NO;
+  resultAttachmentPointer.fileName = @"";
+  return self;
+}
 @end
 
 @interface OWSSignalServiceProtosGroupContext ()
@@ -6001,6 +6052,7 @@ BOOL OWSSignalServiceProtosGroupContextTypeIsValidValue(OWSSignalServiceProtosGr
     case OWSSignalServiceProtosGroupContextTypeUpdate:
     case OWSSignalServiceProtosGroupContextTypeDeliver:
     case OWSSignalServiceProtosGroupContextTypeQuit:
+    case OWSSignalServiceProtosGroupContextTypeRequestInfo:
       return YES;
     default:
       return NO;
@@ -6016,6 +6068,8 @@ NSString *NSStringFromOWSSignalServiceProtosGroupContextType(OWSSignalServicePro
       return @"OWSSignalServiceProtosGroupContextTypeDeliver";
     case OWSSignalServiceProtosGroupContextTypeQuit:
       return @"OWSSignalServiceProtosGroupContextTypeQuit";
+    case OWSSignalServiceProtosGroupContextTypeRequestInfo:
+      return @"OWSSignalServiceProtosGroupContextTypeRequestInfo";
     default:
       return nil;
   }

src/Util/MIMETypeUtil.h

@@ -29,11 +29,11 @@ extern NSString *const OWSMimeTypeUnknownForTests;
 + (BOOL)isVideo:(NSString *)contentType;
 + (BOOL)isAudio:(NSString *)contentType;
 
-+ (NSString *)filePathForAttachment:(NSString *)uniqueId ofMIMEType:(NSString *)contentType inFolder:(NSString *)folder;
+// filename is optional and should not be trusted.
-+ (NSString *)filePathForImage:(NSString *)uniqueId ofMIMEType:(NSString *)contentType inFolder:(NSString *)folder;
++ (NSString *)filePathForAttachment:(NSString *)uniqueId
-+ (NSString *)filePathForVideo:(NSString *)uniqueId ofMIMEType:(NSString *)contentType inFolder:(NSString *)folder;
+                         ofMIMEType:(NSString *)contentType
-+ (NSString *)filePathForAudio:(NSString *)uniqueId ofMIMEType:(NSString *)contentType inFolder:(NSString *)folder;
+                           filename:(nullable NSString *)filename
-+ (NSString *)filePathForAnimated:(NSString *)uniqueId ofMIMEType:(NSString *)contentType inFolder:(NSString *)folder;
+                           inFolder:(NSString *)folder;
 
 + (NSURL *)simLinkCorrectExtensionOfFile:(NSURL *)mediaURL ofMIMEType:(NSString *)contentType;
 

src/Util/MIMETypeUtil.m

@@ -261,7 +261,70 @@ NSString *const OWSMimeTypeUnknownForTests = @"unknown/mimetype";
 
 + (NSString *)filePathForAttachment:(NSString *)uniqueId
                          ofMIMEType:(NSString *)contentType
-                           inFolder:(NSString *)folder {
+                           filename:(nullable NSString *)filename
+                           inFolder:(NSString *)folder
+{
+    NSString *kDefaultFileExtension = @"bin";
+
+    if (filename.length > 0) {
+        NSString *normalizedFilename =
+            [filename stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
+        // Ensure that the filename is a valid filesystem name,
+        // replacing invalid characters with an underscore.
+        for (NSCharacterSet *invalidCharacterSet in @[
+                 [NSCharacterSet whitespaceAndNewlineCharacterSet],
+                 [NSCharacterSet illegalCharacterSet],
+                 [NSCharacterSet controlCharacterSet],
+                 [NSCharacterSet characterSetWithCharactersInString:@"<>|\\:()&;?*/~"],
+             ]) {
+            normalizedFilename = [[normalizedFilename componentsSeparatedByCharactersInSet:invalidCharacterSet]
+                componentsJoinedByString:@"_"];
+        }
+        
+        // Remove leading periods to prevent hidden files,
+        // "." and ".." special file names.
+        while ([normalizedFilename hasPrefix:@"."]) {
+            normalizedFilename = [normalizedFilename substringFromIndex:1];
+        }
+
+        NSString *fileExtension = [[normalizedFilename pathExtension]
+            stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
+        NSString *filenameWithoutExtension = [[[normalizedFilename lastPathComponent] stringByDeletingPathExtension]
+            stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
+
+        // If the filename has not file extension, deduce one
+        // from the MIME type.
+        if (fileExtension.length < 1) {
+            fileExtension = [self fileExtensionForMIMEType:contentType];
+            if (fileExtension.length < 1) {
+                fileExtension = kDefaultFileExtension;
+            }
+        }
+        fileExtension = [fileExtension lowercaseString];
+
+        if (filenameWithoutExtension.length > 0) {
+            // Store the file in a subdirectory whose name is the uniqueId of this attachment,
+            // to avoid collisions between multiple attachments with the same name.
+            NSString *attachmentFolderPath = [folder stringByAppendingPathComponent:uniqueId];
+            NSError *error = nil;
+            BOOL attachmentFolderPathExists = [[NSFileManager defaultManager] fileExistsAtPath:attachmentFolderPath];
+            if (!attachmentFolderPathExists) {
+                [[NSFileManager defaultManager] createDirectoryAtPath:attachmentFolderPath
+                                          withIntermediateDirectories:YES
+                                                           attributes:nil
+                                                                error:&error];
+                if (error) {
+                    DDLogError(@"Failed to create attachment directory: %@", error);
+                    OWSAssert(0);
+                    return nil;
+                }
+            }
+            return [attachmentFolderPath
+                stringByAppendingPathComponent:[NSString
+                                                   stringWithFormat:@"%@.%@", filenameWithoutExtension, fileExtension]];
+        }
+    }
+
     if ([self isVideo:contentType]) {
         return [MIMETypeUtil filePathForVideo:uniqueId ofMIMEType:contentType inFolder:folder];
     } else if ([self isAudio:contentType]) {
@@ -291,7 +354,7 @@ NSString *const OWSMimeTypeUnknownForTests = @"unknown/mimetype";
 
     DDLogError(@"Got asked for path of file %@ which is unsupported", contentType);
     // Use a fallback file extension.
-    return [self filePathForData:uniqueId withFileExtension:@"bin" inFolder:folder];
+    return [self filePathForData:uniqueId withFileExtension:kDefaultFileExtension inFolder:folder];
 }
 
 + (NSURL *)simLinkCorrectExtensionOfFile:(NSURL *)mediaURL ofMIMEType:(NSString *)contentType {