Merge branch 'bc/hash-algo'

An infrastructure to define what hash function is used in Git is
introduced, and an effort to plumb that throughout various
codepaths has been started.

* bc/hash-algo:
  repository: fix a sparse 'using integer as NULL pointer' warning
  Switch empty tree and blob lookups to use hash abstraction
  Integrate hash algorithm support with repo setup
  Add structure representing hash algorithm
  setup: expose enumerated repo info

1 files changed, 8 insertions, 4 deletions

diff --git a/cache.h b/cache.h
index cb5db7bf83..d3e240228c 100644
--- a/cache.h
+++ b/cache.h
@@ -14,6 +14,7 @@
 #include "hash.h"
 #include "path.h"
 #include "sha1-array.h"
+#include "repository.h"
 
 #ifndef platform_SHA_CTX
 /*
@@ -77,6 +78,8 @@ struct object_id {
 	unsigned char hash[GIT_MAX_RAWSZ];
 };
 
+#define the_hash_algo the_repository->hash_algo
+
 #if defined(DT_UNKNOWN) && !defined(NO_D_TYPE_IN_DIRENT)
 #define DTYPE(de)	((de)->d_type)
 #else
@@ -907,6 +910,7 @@ struct repository_format {
 	int version;
 	int precious_objects;
 	int is_bare;
+	int hash_algo;
 	char *work_tree;
 	struct string_list unknown_extensions;
 };
@@ -1039,22 +1043,22 @@ extern const struct object_id empty_blob_oid;
 
 static inline int is_empty_blob_sha1(const unsigned char *sha1)
 {
-	return !hashcmp(sha1, EMPTY_BLOB_SHA1_BIN);
+	return !hashcmp(sha1, the_hash_algo->empty_blob->hash);
 }
 
 static inline int is_empty_blob_oid(const struct object_id *oid)
 {
-	return !hashcmp(oid->hash, EMPTY_BLOB_SHA1_BIN);
+	return !oidcmp(oid, the_hash_algo->empty_blob);
 }
 
 static inline int is_empty_tree_sha1(const unsigned char *sha1)
 {
-	return !hashcmp(sha1, EMPTY_TREE_SHA1_BIN);
+	return !hashcmp(sha1, the_hash_algo->empty_tree->hash);
 }
 
 static inline int is_empty_tree_oid(const struct object_id *oid)
 {
-	return !hashcmp(oid->hash, EMPTY_TREE_SHA1_BIN);
+	return !oidcmp(oid, the_hash_algo->empty_tree);
 }
 
 /* set default permissions by passing mode arguments to open(2) */