diff options
authorAtousa Pahlevan Duprat <>2015-11-05 06:38:41 (GMT)
committerJunio C Hamano <>2015-11-05 18:35:11 (GMT)
commit3bc72fde3f35b988c902abf5a0bc027f2e54d0c1 (patch)
parent441c4a40173fe1ee8a5c0094e587dfc47e2a6460 (diff)
sha1: provide another level of indirection for the SHA-1 functions
The git source uses git_SHA1_Update() and friends to call into the code that computes the hashes. Traditionally, we used to map these directly to underlying implementation of the SHA-1 hash (e.g. SHA1_Update() from OpenSSL or blk_SHA1_Update() from block-sha1/). This arrangement however makes it hard to tweak behaviour of the underlying implementation without fully replacing. If we want to introduce a tweaked_SHA1_Update() wrapper to implement the "Update" in a slightly different way, for example, the implementation of the wrapper still would want to call into the underlying implementation, but tweaked_SHA1_Update() cannot call git_SHA1_Update() to get to the underlying implementation (often but not always SHA1_Update()). Add another level of indirection that maps platform_SHA1_Update() and friends to their underlying implementations, and by default make git_SHA1_Update() and friends map to platform_SHA1_* functions. Doing it this way will later allow us to map git_SHA1_Update() to tweaked_SHA1_Update(), and the latter can use platform_SHA1_Update() in its implementation. Signed-off-by: Atousa Pahlevan Duprat <> Signed-off-by: Junio C Hamano <>
3 files changed, 25 insertions, 13 deletions
diff --git a/block-sha1/sha1.h b/block-sha1/sha1.h
index b864df6..4df6747 100644
--- a/block-sha1/sha1.h
+++ b/block-sha1/sha1.h
@@ -16,7 +16,7 @@ void blk_SHA1_Init(blk_SHA_CTX *ctx);
void blk_SHA1_Update(blk_SHA_CTX *ctx, const void *dataIn, unsigned long len);
void blk_SHA1_Final(unsigned char hashout[20], blk_SHA_CTX *ctx);
-#define git_SHA_CTX blk_SHA_CTX
-#define git_SHA1_Init blk_SHA1_Init
-#define git_SHA1_Update blk_SHA1_Update
-#define git_SHA1_Final blk_SHA1_Final
+#define platform_SHA_CTX blk_SHA_CTX
+#define platform_SHA1_Init blk_SHA1_Init
+#define platform_SHA1_Update blk_SHA1_Update
+#define platform_SHA1_Final blk_SHA1_Final
diff --git a/cache.h b/cache.h
index 22b7b81..0d89ad8 100644
--- a/cache.h
+++ b/cache.h
@@ -11,13 +11,25 @@
#include "string-list.h"
#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
+#ifndef platform_SHA_CTX
+ * platform's underlying implementation of SHA-1; could be OpenSSL,
+ * blk_SHA, Apple CommonCrypto, etc... Note that including
+ * SHA1_HEADER may have already defined platform_SHA_CTX for our
+ * own implementations like block-sha1 and ppc-sha1, so we list
+ * the default for OpenSSL compatible SHA-1 implementations here.
+ */
+#define platform_SHA_CTX SHA_CTX
+#define platform_SHA1_Init SHA1_Init
+#define platform_SHA1_Update SHA1_Update
+#define platform_SHA1_Final SHA1_Final
+#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
#include <zlib.h>
typedef struct git_zstream {
z_stream z;
diff --git a/ppc/sha1.h b/ppc/sha1.h
index c405f73..9b24b32 100644
--- a/ppc/sha1.h
+++ b/ppc/sha1.h
@@ -19,7 +19,7 @@ int ppc_SHA1_Init(ppc_SHA_CTX *c);
int ppc_SHA1_Update(ppc_SHA_CTX *c, const void *p, unsigned long n);
int ppc_SHA1_Final(unsigned char *hash, ppc_SHA_CTX *c);
-#define git_SHA_CTX ppc_SHA_CTX
-#define git_SHA1_Init ppc_SHA1_Init
-#define git_SHA1_Update ppc_SHA1_Update
-#define git_SHA1_Final ppc_SHA1_Final
+#define platform_SHA_CTX ppc_SHA_CTX
+#define platform_SHA1_Init ppc_SHA1_Init
+#define platform_SHA1_Update ppc_SHA1_Update
+#define platform_SHA1_Final ppc_SHA1_Final