Respond to CR.

// FREEBIE

src/Messages/Attachments/TSAttachment.h

@@ -6,8 +6,6 @@
 
 NS_ASSUME_NONNULL_BEGIN
 
-@class TSAttachmentPointer;
-
 @interface TSAttachment : TSYapDatabaseObject {
 
 @protected
@@ -24,7 +22,6 @@ NS_ASSUME_NONNULL_BEGIN
 @property (atomic, readwrite) UInt64 serverId;
 @property (atomic, readwrite) NSData *encryptionKey;
 @property (nonatomic, readonly) NSString *contentType;
-// This property
 
 @property (atomic, readwrite) BOOL isDownloaded;
 
@@ -40,7 +37,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 // This constructor is used for new instances of TSAttachmentStream
 // that represent downloaded incoming attachments.
-- (instancetype)initWithPointer:(TSAttachmentPointer *)pointer;
+- (instancetype)initWithPointer:(TSAttachment *)pointer;
 
 - (void)upgradeFromAttachmentSchemaVersion:(NSUInteger)attachmentSchemaVersion;
 

src/Messages/Attachments/TSAttachment.m

@@ -4,7 +4,6 @@
 
 #import "TSAttachment.h"
 #import "MIMETypeUtil.h"
-#import "TSAttachmentPointer.h"
 
 NS_ASSUME_NONNULL_BEGIN
 
@@ -54,7 +53,7 @@ NSUInteger const TSAttachmentSchemaVersion = 3;
 
 // This constructor is used for new instances of TSAttachmentStream
 // that represent downloaded incoming attachments.
-- (instancetype)initWithPointer:(TSAttachmentPointer *)pointer
+- (instancetype)initWithPointer:(TSAttachment *)pointer
 {
     // Once saved, this AttachmentStream will replace the AttachmentPointer in the attachments collection.
     self = [super initWithUniqueId:pointer.uniqueId];
@@ -70,11 +69,6 @@ NSUInteger const TSAttachmentSchemaVersion = 3;
     return self;
 }
 
-- (BOOL)isDecimalNumberText:(NSString *)text
-{
-    return [text componentsSeparatedByCharactersInSet:[NSCharacterSet decimalDigitCharacterSet]].count == 1;
-}
-
 - (nullable instancetype)initWithCoder:(NSCoder *)coder
 {
     self = [super initWithCoder:coder];
@@ -92,25 +86,8 @@ NSUInteger const TSAttachmentSchemaVersion = 3;
 
 - (void)upgradeFromAttachmentSchemaVersion:(NSUInteger)attachmentSchemaVersion
 {
-    // TSAttachment is a base class for TSAttachmentPointer (a yet-to-be-downloaded
-    // incoming attachment) and TSAttachmentStream (an outgoing or already-downloaded
-    // incoming attachment).
-    //
-    // The attachmentSchemaVersion and serverId properties only apply to
-    // TSAttachmentPointer, which can be distinguished by the isDownloaded
-    // property.
-    if (!_isDownloaded && _attachmentSchemaVersion < 2) {
-        if (!_serverId) {
-            OWSAssert([self isDecimalNumberText:self.uniqueId]);
-            if (![self isDecimalNumberText:self.uniqueId]) {
-                DDLogError(@"%@ invalid legacy attachment uniqueId: %@.", self.tag, self.uniqueId);
-            }
-            _serverId = [self.uniqueId integerValue];
-            if (!_serverId) {
-                DDLogError(@"%@ failed to parse legacy attachment uniqueId: %@.", self.tag, self.uniqueId);
-            }
-        }
-    }
+    // This method is overridden by the base classes TSAttachmentPointer and
+    // TSAttachmentStream.
 }
 
 + (NSString *)collection {

src/Messages/Attachments/TSAttachmentPointer.m

@@ -28,6 +28,38 @@ NS_ASSUME_NONNULL_BEGIN
     return self;
 }
 
+- (BOOL)isDecimalNumberText:(NSString *)text
+{
+    return [text componentsSeparatedByCharactersInSet:[NSCharacterSet decimalDigitCharacterSet]].count == 1;
+}
+
+- (void)upgradeFromAttachmentSchemaVersion:(NSUInteger)attachmentSchemaVersion
+{
+    // Legacy instances of TSAttachmentPointer apparently used the serverId as their
+    // uniqueId.
+    if (attachmentSchemaVersion < 2 && self.serverId == 0) {
+        OWSAssert([self isDecimalNumberText:self.uniqueId]);
+        if ([self isDecimalNumberText:self.uniqueId]) {
+            // For legacy instances, try to parse the serverId from the uniqueId.
+            self.serverId = [self.uniqueId integerValue];
+        } else {
+            DDLogError(@"%@ invalid legacy attachment uniqueId: %@.", self.tag, self.uniqueId);
+        }
+    }
+}
+
+#pragma mark - Logging
+
++ (NSString *)tag
+{
+    return [NSString stringWithFormat:@"[%@]", self.class];
+}
+
+- (NSString *)tag
+{
+    return self.class.tag;
+}
+
 @end
 
 NS_ASSUME_NONNULL_END