repack: move 'delta_base_offset' to 'struct pack_objects_args'

The static variable 'delta_base_offset' determines whether or not we
pass the "--delta-base-offset" command-line argument when spawning
pack-objects as a child process. Its introduction dates back to when
repack was rewritten in C, all the way back in a1bbc6c (repack:
rewrite the shell script in C, 2013-09-15).

'struct pack_objects_args' was introduced much later on in 4571324
(builtin/repack.c: allow configuring cruft pack generation, 2022-05-20),
but did not move the 'delta_base_offset' variable.

Since the 'delta_base_offset' is a property of an individual
pack-objects command, re-introduce that variable as a member of 'struct
pack_objects_args', which will enable further code movement in the
subsequent commits.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: ttaylorr

builtin/repack.c

@@ -34,7 +34,6 @@
 #define RETAIN_PACK 2
 
 static int pack_everything;
-static int delta_base_offset = 1;
 static int pack_kept_objects = -1;
 static int write_bitmaps = -1;
 static int use_delta_islands;
@@ -63,9 +62,10 @@ static int repack_config(const char *var, const char *value,
 			 const struct config_context *ctx, void *cb)
 {
 	struct repack_config_ctx *repack_ctx = cb;
+	struct pack_objects_args *po_args = repack_ctx->po_args;
 	struct pack_objects_args *cruft_po_args = repack_ctx->cruft_po_args;
 	if (!strcmp(var, "repack.usedeltabaseoffset")) {
-		delta_base_offset = git_config_bool(var, value);
+		po_args->delta_base_offset = git_config_bool(var, value);
 		return 0;
 	}
 	if (!strcmp(var, "repack.packkeptobjects")) {
@@ -315,7 +315,7 @@ static void prepare_pack_objects(struct child_process *cmd,
 		strvec_push(&cmd->args,  "--local");
 	if (args->quiet)
 		strvec_push(&cmd->args,  "--quiet");
-	if (delta_base_offset)
+	if (args->delta_base_offset)
 		strvec_push(&cmd->args,  "--delta-base-offset");
 	strvec_push(&cmd->args, out);
 	cmd->git_cmd = 1;
@@ -1271,8 +1271,8 @@ int cmd_repack(int argc,
 	const char *unpack_unreachable = NULL;
 	int keep_unreachable = 0;
 	struct string_list keep_pack_list = STRING_LIST_INIT_NODUP;
-	struct pack_objects_args po_args = { 0 };
-	struct pack_objects_args cruft_po_args = { 0 };
+	struct pack_objects_args po_args = PACK_OBJECTS_ARGS_INIT;
+	struct pack_objects_args cruft_po_args = PACK_OBJECTS_ARGS_INIT;
 	int write_midx = 0;
 	const char *cruft_expiration = NULL;
 	const char *expire_to = NULL;
@@ -1567,6 +1567,7 @@ int cmd_repack(int argc,
 
 		cruft_po_args.local = po_args.local;
 		cruft_po_args.quiet = po_args.quiet;
+		cruft_po_args.delta_base_offset = po_args.delta_base_offset;
 
 		ret = write_cruft_pack(&cruft_po_args, packtmp, pack_prefix,
 				       cruft_expiration,

repack.h

@@ -15,9 +15,12 @@ struct pack_objects_args {
 	int local;
 	int name_hash_version;
 	int path_walk;
+	int delta_base_offset;
 	struct list_objects_filter_options filter_options;
 };
 
+#define PACK_OBJECTS_ARGS_INIT { .delta_base_offset = 1 }
+
 void pack_objects_args_release(struct pack_objects_args *args);
 
 #endif /* REPACK_H */