From cfe83216e404223ce8c5f6ef79c4ba9a27ff872e Mon Sep 17 00:00:00 2001
From: Derrick Stolee <dstolee@microsoft.com>
Date: Mon, 2 Apr 2018 16:34:15 -0400
Subject: csum-file: refactor finalize_hashfile() method

If we want to use a hashfile on the temporary file for a lockfile, then
we need finalize_hashfile() to fully write the trailing hash but also keep
the file descriptor open.

Do this by adding a new CSUM_HASH_IN_STREAM flag along with a functional
change that checks this flag before writing the checksum to the stream.
This differs from previous behavior since it would be written if either
CSUM_CLOSE or CSUM_FSYNC is provided.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index 5126623..c4a5a95 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -837,9 +837,9 @@ static void write_pack_file(void)
 		 * If so, rewrite it like in fast-import
 		 */
 		if (pack_to_stdout) {
-			finalize_hashfile(f, oid.hash, CSUM_CLOSE);
+			finalize_hashfile(f, oid.hash, CSUM_HASH_IN_STREAM | CSUM_CLOSE);
 		} else if (nr_written == nr_remaining) {
-			finalize_hashfile(f, oid.hash, CSUM_FSYNC);
+			finalize_hashfile(f, oid.hash, CSUM_HASH_IN_STREAM | CSUM_FSYNC | CSUM_CLOSE);
 		} else {
 			int fd = finalize_hashfile(f, oid.hash, 0);
 			fixup_pack_header_footer(fd, oid.hash, pack_tmp_name,
diff --git a/bulk-checkin.c b/bulk-checkin.c
index e8094f5..a3e1b59 100644
--- a/bulk-checkin.c
+++ b/bulk-checkin.c
@@ -35,7 +35,7 @@ static void finish_bulk_checkin(struct bulk_checkin_state *state)
 		unlink(state->pack_tmp_name);
 		goto clear_exit;
 	} else if (state->nr_written == 1) {
-		finalize_hashfile(state->f, oid.hash, CSUM_FSYNC);
+		finalize_hashfile(state->f, oid.hash, CSUM_HASH_IN_STREAM | CSUM_FSYNC | CSUM_CLOSE);
 	} else {
 		int fd = finalize_hashfile(state->f, oid.hash, 0);
 		fixup_pack_header_footer(fd, oid.hash, state->pack_tmp_name,
diff --git a/csum-file.c b/csum-file.c
index e6c95a6..53ce37f 100644
--- a/csum-file.c
+++ b/csum-file.c
@@ -61,11 +61,11 @@ int finalize_hashfile(struct hashfile *f, unsigned char *result, unsigned int fl
 	the_hash_algo->final_fn(f->buffer, &f->ctx);
 	if (result)
 		hashcpy(result, f->buffer);
-	if (flags & (CSUM_CLOSE | CSUM_FSYNC)) {
-		/* write checksum and close fd */
+	if (flags & CSUM_HASH_IN_STREAM)
 		flush(f, f->buffer, the_hash_algo->rawsz);
-		if (flags & CSUM_FSYNC)
-			fsync_or_die(f->fd, f->name);
+	if (flags & CSUM_FSYNC)
+		fsync_or_die(f->fd, f->name);
+	if (flags & CSUM_CLOSE) {
 		if (close(f->fd))
 			die_errno("%s: sha1 file error on close", f->name);
 		fd = 0;
diff --git a/csum-file.h b/csum-file.h
index 9ba87f0..c5a2e33 100644
--- a/csum-file.h
+++ b/csum-file.h
@@ -27,8 +27,9 @@ extern void hashfile_checkpoint(struct hashfile *, struct hashfile_checkpoint *)
 extern int hashfile_truncate(struct hashfile *, struct hashfile_checkpoint *);
 
 /* finalize_hashfile flags */
-#define CSUM_CLOSE	1
-#define CSUM_FSYNC	2
+#define CSUM_CLOSE		1
+#define CSUM_FSYNC		2
+#define CSUM_HASH_IN_STREAM	4
 
 extern struct hashfile *hashfd(int fd, const char *name);
 extern struct hashfile *hashfd_check(const char *name);
diff --git a/pack-bitmap-write.c b/pack-bitmap-write.c
index 662b44f..db4c832 100644
--- a/pack-bitmap-write.c
+++ b/pack-bitmap-write.c
@@ -535,7 +535,7 @@ void bitmap_writer_finish(struct pack_idx_entry **index,
 	if (options & BITMAP_OPT_HASH_CACHE)
 		write_hash_cache(f, index, index_nr);
 
-	finalize_hashfile(f, NULL, CSUM_FSYNC);
+	finalize_hashfile(f, NULL, CSUM_HASH_IN_STREAM | CSUM_FSYNC | CSUM_CLOSE);
 
 	if (adjust_shared_perm(tmp_file.buf))
 		die_errno("unable to make temporary bitmap file readable");
diff --git a/pack-write.c b/pack-write.c
index 044f427..a9d46bc 100644
--- a/pack-write.c
+++ b/pack-write.c
@@ -170,8 +170,9 @@ const char *write_idx_file(const char *index_name, struct pack_idx_entry **objec
 	}
 
 	hashwrite(f, sha1, the_hash_algo->rawsz);
-	finalize_hashfile(f, NULL, ((opts->flags & WRITE_IDX_VERIFY)
-				    ? CSUM_CLOSE : CSUM_FSYNC));
+	finalize_hashfile(f, NULL, CSUM_HASH_IN_STREAM | CSUM_CLOSE |
+				    ((opts->flags & WRITE_IDX_VERIFY)
+				    ? 0 : CSUM_FSYNC));
 	return index_name;
 }
 
-- 
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