mv: replace src_dir with a strvec

We manually manage the src_dir array with ALLOC_GROW. Using a strvec is
a little more ergonomic, and makes the memory ownership more clear. It
does mean that we copy the strings (which were otherwise just pointers
into the "sources" strvec), but using the same rationale as 9fcd9e4
(builtin/mv duplicate string list memory, 2024-05-27), it's just not
enough to be worth worrying about here.

As a bonus, this gets rid of some "int"s used for allocation management
(though in practice these were limited to command-line sizes and thus
not overflowable).

Signed-off-by: Jeff King <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: peff

builtin/mv.c

@@ -197,8 +197,7 @@ int cmd_mv(int argc, const char **argv, const char *prefix)
 	struct strvec submodule_gitfiles_to_free = STRVEC_INIT;
 	const char **submodule_gitfiles;
 	char *dst_w_slash = NULL;
-	const char **src_dir = NULL;
-	int src_dir_nr = 0, src_dir_alloc = 0;
+	struct strvec src_dir = STRVEC_INIT;
 	enum update_mode *modes, dst_mode = 0;
 	struct stat st, dest_st;
 	struct string_list src_for_dst = STRING_LIST_INIT_DUP;
@@ -344,8 +343,7 @@ int cmd_mv(int argc, const char **argv, const char *prefix)
 			/* last - first >= 1 */
 			modes[i] |= WORKING_DIRECTORY;
 
-			ALLOC_GROW(src_dir, src_dir_nr + 1, src_dir_alloc);
-			src_dir[src_dir_nr++] = src;
+			strvec_push(&src_dir, src);
 
 			n = argc + last - first;
 			REALLOC_ARRAY(modes, n);
@@ -559,7 +557,7 @@ int cmd_mv(int argc, const char **argv, const char *prefix)
 		}
 	}
 
-	remove_empty_src_dirs(src_dir, src_dir_nr);
+	remove_empty_src_dirs(src_dir.v, src_dir.nr);
 
 	if (dirty_paths.nr)
 		advise_on_moving_dirty_path(&dirty_paths);
@@ -574,7 +572,7 @@ int cmd_mv(int argc, const char **argv, const char *prefix)
 	ret = 0;
 
 out:
-	free(src_dir);
+	strvec_clear(&src_dir);
 	free(dst_w_slash);
 	string_list_clear(&src_for_dst, 0);
 	string_list_clear(&dirty_paths, 0);