pack-write: pass hash_algo to write_rev_file()

The `write_rev_file()` function uses the global `the_hash_algo` variable
to access the repository's hash function. To avoid global variable
usage, let's pass the hash function from the layers above.

Altough the layers above could have access to the hash function
internally, simply pass in `the_hash_algo`. This avoids any
compatibility issues and bubbles up global variable usage to upper
layers which can be eventually resolved.

However, in `midx-write.c`, since all usage of global variables is
removed, don't reintroduce them and instead use the `repo` available in
the context.

Signed-off-by: Karthik Nayak <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: KarthikNayak

builtin/index-pack.c

@@ -2096,9 +2096,9 @@ int cmd_index_pack(int argc,
 	curr_index = write_idx_file(the_hash_algo, index_name, idx_objects,
 				    nr_objects, &opts, pack_hash);
 	if (rev_index)
-		curr_rev_index = write_rev_file(rev_index_name, idx_objects,
-						nr_objects, pack_hash,
-						opts.flags);
+		curr_rev_index = write_rev_file(the_hash_algo, rev_index_name,
+						idx_objects, nr_objects,
+						pack_hash, opts.flags);
 	free(idx_objects);
 
 	if (!verify)

midx-write.c

@@ -658,8 +658,8 @@ static void write_midx_reverse_index(char *midx_name, unsigned char *midx_hash,
 	strbuf_addf(&buf, "%s-%s.rev", midx_name, hash_to_hex_algop(midx_hash,
 								    ctx->repo->hash_algo));
 
-	tmp_file = write_rev_file_order(NULL, ctx->pack_order, ctx->entries_nr,
-					midx_hash, WRITE_REV);
+	tmp_file = write_rev_file_order(ctx->repo->hash_algo, NULL, ctx->pack_order,
+					ctx->entries_nr, midx_hash, WRITE_REV);
 
 	if (finalize_object_file(tmp_file, buf.buf))
 		die(_("cannot store reverse index file"));

pack-write.c

@@ -194,11 +194,12 @@ static int pack_order_cmp(const void *va, const void *vb, void *ctx)
 	return 0;
 }
 
-static void write_rev_header(struct hashfile *f)
+static void write_rev_header(const struct git_hash_algo *hash_algo,
+			     struct hashfile *f)
 {
 	hashwrite_be32(f, RIDX_SIGNATURE);
 	hashwrite_be32(f, RIDX_VERSION);
-	hashwrite_be32(f, oid_version(the_hash_algo));
+	hashwrite_be32(f, oid_version(hash_algo));
 }
 
 static void write_rev_index_positions(struct hashfile *f,
@@ -215,7 +216,8 @@ static void write_rev_trailer(struct hashfile *f, const unsigned char *hash)
 	hashwrite(f, hash, the_hash_algo->rawsz);
 }
 
-char *write_rev_file(const char *rev_name,
+char *write_rev_file(const struct git_hash_algo *hash_algo,
+		     const char *rev_name,
 		     struct pack_idx_entry **objects,
 		     uint32_t nr_objects,
 		     const unsigned char *hash,
@@ -233,15 +235,16 @@ char *write_rev_file(const char *rev_name,
 		pack_order[i] = i;
 	QSORT_S(pack_order, nr_objects, pack_order_cmp, objects);
 
-	ret = write_rev_file_order(rev_name, pack_order, nr_objects, hash,
-				   flags);
+	ret = write_rev_file_order(hash_algo, rev_name, pack_order, nr_objects,
+				   hash, flags);
 
 	free(pack_order);
 
 	return ret;
 }
 
-char *write_rev_file_order(const char *rev_name,
+char *write_rev_file_order(const struct git_hash_algo *hash_algo,
+			   const char *rev_name,
 			   uint32_t *pack_order,
 			   uint32_t nr_objects,
 			   const unsigned char *hash,
@@ -280,7 +283,7 @@ char *write_rev_file_order(const char *rev_name,
 		return NULL;
 	}
 
-	write_rev_header(f);
+	write_rev_header(hash_algo, f);
 
 	write_rev_index_positions(f, pack_order, nr_objects);
 	write_rev_trailer(f, hash);
@@ -568,8 +571,8 @@ void stage_tmp_packfiles(const struct git_hash_algo *hash_algo,
 	if (adjust_shared_perm(*idx_tmp_name))
 		die_errno("unable to make temporary index file readable");
 
-	rev_tmp_name = write_rev_file(NULL, written_list, nr_written, hash,
-				      pack_idx_opts->flags);
+	rev_tmp_name = write_rev_file(hash_algo, NULL, written_list, nr_written,
+				      hash, pack_idx_opts->flags);
 
 	if (pack_idx_opts->flags & WRITE_MTIMES) {
 		mtimes_tmp_name = write_mtimes_file(to_pack, written_list,

pack.h

@@ -105,8 +105,18 @@ struct ref;
 
 void write_promisor_file(const char *promisor_name, struct ref **sought, int nr_sought);
 
-char *write_rev_file(const char *rev_name, struct pack_idx_entry **objects, uint32_t nr_objects, const unsigned char *hash, unsigned flags);
-char *write_rev_file_order(const char *rev_name, uint32_t *pack_order, uint32_t nr_objects, const unsigned char *hash, unsigned flags);
+char *write_rev_file(const struct git_hash_algo *hash_algo,
+		     const char *rev_name,
+		     struct pack_idx_entry **objects,
+		     uint32_t nr_objects,
+		     const unsigned char *hash,
+		     unsigned flags);
+char *write_rev_file_order(const struct git_hash_algo *hash_algo,
+			   const char *rev_name,
+			   uint32_t *pack_order,
+			   uint32_t nr_objects,
+			   const unsigned char *hash,
+			   unsigned flags);
 
 /*
  * The "hdr" output buffer should be at least this big, which will handle sizes