Bug: Photo hash comparison is case sensitive

[dereck009]

I have an ejabberd installation which sends photo hashes with letters in all uppercase.

The vCardTempCoreDataStorageObject calculates its own hash from the data with letters in all lowercase.

https://github.com/robbiehanson/XMPPFramework/blob/master/Extensions/XEP-0054/CoreDataStorage/XMPPvCardCoreDataStorageObject.m#L135

[[photoData xmpp_sha1Digest] xmpp_hexStringValue]

Then the vCardAvatarModule uses case sensitive isEqualToString comparison:

https://github.com/robbiehanson/XMPPFramework/blob/master/Extensions/XEP-0153/XMPPvCardAvatarModule.m#L237

This results in the photo always being fetched from the server.

Suggestion: use the caseInsensitiveCompare string method to compare hashes!

[dereck009]

The comparison: https://github.com/robbiehanson/XMPPFramework/blob/master/Extensions/XEP-0153/XMPPvCardAvatarModule.m#L237

...should look like this:

// check the hash
if ([photoHash caseInsensitiveCompare:savedPhotoHash] != NSOrderedSame
    && !([photoHash length] == 0 && [savedPhotoHash length] == 0)) {
    [_xmppvCardTempModule fetchvCardTempForJID:jid ignoreStorage:YES];
}

Note: I also used the savedPhotoHash variable which was defined just above this conditional.