Re: [PATCH v5 1/2] cache.h: eliminate SHA-1 deprecation warnings on Mac OS X

[Eric Sunshine <sunshine@sunshineco.com>]

On Wed, May 15, 2013 at 1:56 PM, Torsten Bögershausen <tboegi@web.de> wrote:
> On 2013-05-15 09.11, David Aguilar wrote:
>> +     ifndef NO_APPLE_COMMON_CRYPTO
>> +             APPLE_COMMON_CRYPTO = YesPlease
>> +     endif
>>       NO_REGEX = YesPlease
>>       PTHREAD_LIBS =
>>  endif
>> @@ -1389,10 +1396,16 @@ ifdef PPC_SHA1
>>       LIB_OBJS += ppc/sha1.o ppc/sha1ppc.o
>>       LIB_H += ppc/sha1.h
>>  else
>> +ifdef APPLE_COMMON_CRYPTO
>> +     BASIC_CFLAGS += -DCOMMON_DIGEST_FOR_OPENSSL
>> +     SHA1_HEADER = <CommonCrypto/CommonDigest.h>
>
> Would it make sense to replace APPLE_COMMON_CRYPTO
> with COMMON_DIGEST_FOR_OPENSSL ?
>
> In the spirit of other Makefile-defines becoming Compiler defines,
> a random picked example:
> ifdef NO_STRTOULL
>         COMPAT_CFLAGS += -DNO_STRTOULL
> endif

Not necessarily. Unlike NO_STRTOULL and cousins,
COMMON_DIGEST_FOR_OPENSSL is not a Git build tweak; it is merely a
(public) implementation detail of the Apple header [1] to magically
associate OpenSSL digest functions with CommonCrypto counterparts.
It's not the only such macro recognized by the Apple headers. For
instance, COMMON_DIGEST_FOR_RFC_1321 magically associates legacy MD5
digest functions with CommonCrypto counterparts.

Further, as Junio noted elsewhere, David is using CommonCrypto for
HMAC replacements, not just for digest replacements, so a Makefile
knob with DIGEST in its name is not really appropriate. More
generally, David would like to find CommonCrypto replacements for all
the OpenSSL functionality, so a Makefile knob named after DIGEST is
too specific.

These considerations motivated the original suggestion for a single
Git Makefile knob to enable/disable, as a unit, all CommonCrypto
replacements. Such a knob would naturally have COMMON_CRYPTO as part
of its name.

[1]: /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.8.sdk/usr/include/CommonCrypto/CommonDigest.h

-- ES