From: Nguyen Thai Ngoc Duy <pclouds@gmail.com>
Date: Tue, 28 Feb 2012 01:08:42 GMT
Subject: Re: [PATCH 03/11] cat-file: use streaming interface to print blobs
Message-ID: <CACsJy8Aa_KRTYVMy8SgB91D3g_=DwP_noxWAO7NWYuQupKPcyA@mail.gmail.com>
In-Reply-To: <7vzkc49nnu.fsf@alter.siamese.dyndns.org>

2012/2/28 Junio C Hamano <gitster@pobox.com>:
>> +             enum object_type type;
>> +             unsigned long size;
>> +             char *buffer = read_sha1_file(sha1, &type, &size);
>> +             if (memcmp(buffer, "object ", 7) ||
>> +                 get_sha1_hex(buffer + 7, new_sha1))
>> +                     die("%s not a valid tag", sha1_to_hex(sha1));
>> +             sha1 = new_sha1;
>> +             free(buffer);
>> +     }
>> +
>> +     return streaming_write_sha1(1, 0, sha1, OBJ_BLOB, NULL);
>
> I do not think your previous refactoring added a fall-back codepath to the
> function you are calling here.  In the original context, the caller of
> streaming_write_entry() made sure that the blob is suitable for streaming
> write by getting an istream, and called the function only when that is the
> case.  Blobs unsuitable for streaming (e.g. an deltified object in a pack)
> were handled by the caller that decided not to call
> streaming_write_entry() with the conventional "read to core and then write
> it out" codepath.
>
> And I do not think your updated caller in cat_one_file() is equipped to do
> so at all.
>
> So it looks to me that this patch totally breaks the cat-file.  What am I
> missing?

I think open_istream can deal with unsuitable for streaming objects
too. There's a fallback "incore" backend that does
read_sha1_file_extended.
-- 
Duy