[PATCH v4 1/3] Provide another level of abstraction for the SHA1 utilities.

[atousa.p@gmail.com]

From: Atousa Pahlevan Duprat <apahlevan@ieee.org>

The git source uses git_SHA1_Update() and friends to call
into the code that computes the hashes.  This is can then be
mapped directly to an implementation that computes the hash,
such as platform_SHA1_Update(); or as we will do in a subsequent
patch, it can be mapped to something more complex that will in turn call
into the platform's SHA implementation.

Signed-off-by: Atousa Pahlevan Duprat <apahlevan@ieee.org>
---
 cache.h | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/cache.h b/cache.h
index a9aaa03..a934a2e 100644
--- a/cache.h
+++ b/cache.h
@@ -12,10 +12,21 @@
 
 #include SHA1_HEADER
 #ifndef git_SHA_CTX
-#define git_SHA_CTX	SHA_CTX
-#define git_SHA1_Init	SHA1_Init
-#define git_SHA1_Update	SHA1_Update
-#define git_SHA1_Final	SHA1_Final
+
+/* platform's underlying implementation of SHA1, could be OpenSSL,
+   blk_SHA, Apple CommonCrypto, etc...  */
+#define platform_SHA_CTX	SHA_CTX
+#define platform_SHA1_Init	SHA1_Init
+#define platform_SHA1_Update	SHA1_Update
+#define platform_SHA1_Final    	SHA1_Final
+
+/* git may call platform's underlying implementation of SHA1 directly,
+   or may call it through a wrapper */
+#define git_SHA_CTX		platform_SHA_CTX
+#define git_SHA1_Init		platform_SHA1_Init
+#define git_SHA1_Update		platform_SHA1_Update
+#define git_SHA1_Final		platform_SHA1_Final
+
 #endif
 
 #include <zlib.h>
-- 
2.4.9 (Apple Git-60)