[PATCH 09/10] object-file.c: add a literal version of write_object_file_prepare()

["Ævar Arnfjörð Bjarmason" <avarab@gmail.com>]

Split off a *_literally() variant of the write_object_file_prepare()
function. To do this create a new "hash_object_body()" static helper.

We now defer the type_name() call until the very last moment in
format_object_header() for those callers that aren't "hash-object
--literally".

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
 object-file.c | 41 ++++++++++++++++++++++++++++++-----------
 1 file changed, 30 insertions(+), 11 deletions(-)

diff --git a/object-file.c b/object-file.c
index 27f587d1dcd..0a6d56db39f 100644
--- a/object-file.c
+++ b/object-file.c
@@ -1775,21 +1775,40 @@ void *read_object_with_reference(struct repository *r,
 	}
 }
 
+static void hash_object_body(const struct git_hash_algo *algo, git_hash_ctx *c,
+			     const void *buf, unsigned long len,
+			     struct object_id *oid,
+			     char *hdr, int *hdrlen)
+{
+	algo->init_fn(c);
+	algo->update_fn(c, hdr, *hdrlen);
+	algo->update_fn(c, buf, len);
+	algo->final_oid_fn(oid, c);
+}
+
 static void write_object_file_prepare(const struct git_hash_algo *algo,
 				      const void *buf, unsigned long len,
-				      const char *type, struct object_id *oid,
+				      enum object_type type, struct object_id *oid,
 				      char *hdr, int *hdrlen)
 {
 	git_hash_ctx c;
 
 	/* Generate the header */
-	*hdrlen = format_object_header_literally(hdr, *hdrlen, type, len);
+	*hdrlen = format_object_header(hdr, *hdrlen, type, len);
 
 	/* Sha1.. */
-	algo->init_fn(&c);
-	algo->update_fn(&c, hdr, *hdrlen);
-	algo->update_fn(&c, buf, len);
-	algo->final_oid_fn(oid, &c);
+	hash_object_body(algo, &c, buf, len, oid, hdr, hdrlen);
+}
+
+static void write_object_file_prepare_literally(const struct git_hash_algo *algo,
+				      const void *buf, unsigned long len,
+				      const char *type, struct object_id *oid,
+				      char *hdr, int *hdrlen)
+{
+	git_hash_ctx c;
+
+	*hdrlen = format_object_header_literally(hdr, *hdrlen, type, len);
+	hash_object_body(algo, &c, buf, len, oid, hdr, hdrlen);
 }
 
 /*
@@ -1849,7 +1868,7 @@ void hash_object_file(const struct git_hash_algo *algo, const void *buf,
 	char hdr[MAX_HEADER_LEN];
 	int hdrlen = sizeof(hdr);
 
-	write_object_file_prepare(algo, buf, len, type_name(type), oid, hdr, &hdrlen);
+	write_object_file_prepare(algo, buf, len, type, oid, hdr, &hdrlen);
 }
 
 static void hash_object_file_literally(const struct git_hash_algo *algo, const void *buf,
@@ -1859,7 +1878,7 @@ static void hash_object_file_literally(const struct git_hash_algo *algo, const v
 	char hdr[MAX_HEADER_LEN];
 	int hdrlen = sizeof(hdr);
 
-	write_object_file_prepare(algo, buf, len, type, oid, hdr, &hdrlen);
+	write_object_file_prepare_literally(algo, buf, len, type, oid, hdr, &hdrlen);
 }
 
 int hash_object_file_oideq(const struct git_hash_algo *algo, const void *buf,
@@ -2036,7 +2055,7 @@ int write_object_file_flags(const void *buf, unsigned long len,
 	/* Normally if we have it in the pack then we do not bother writing
 	 * it out into .git/objects/??/?{38} file.
 	 */
-	write_object_file_prepare(the_hash_algo, buf, len, type_name(type), oid, hdr,
+	write_object_file_prepare(the_hash_algo, buf, len, type, oid, hdr,
 				  &hdrlen);
 	if (freshen_packed_object(oid) || freshen_loose_object(oid))
 		return 0;
@@ -2053,8 +2072,8 @@ int hash_write_object_file_literally(const void *buf, unsigned long len,
 	/* type string, SP, %lu of the length plus NUL must fit this */
 	hdrlen = strlen(type) + MAX_HEADER_LEN;
 	header = xmalloc(hdrlen);
-	write_object_file_prepare(the_hash_algo, buf, len, type, oid, header,
-				  &hdrlen);
+	write_object_file_prepare_literally(the_hash_algo, buf, len, type,
+					    oid, header, &hdrlen);
 
 	if (!(flags & HASH_WRITE_OBJECT))
 		goto cleanup;
-- 
2.35.0.913.g12b4baa2536