add: modify add_files_to_cache() to avoid globals

The function add_files_to_cache() is used by all three of builtin/{add,
checkout, commit}.c.  That suggests this is common library code, and
should be moved somewhere else, like read-cache.c.  However, the
function and its helpers made use of two global variables that made
straight code movement difficult:
  * the_index
  * include_sparse
The latter was perhaps more problematic since it was only accessible in
builtin/add.c but was still affecting builtin/checkout.c and
builtin/commit.c without this fact being very clear from the code.  I'm
not sure if the other two callers would want to add a `--sparse` flag
similar to add.c to get non-default behavior, but exposing this
dependence will help if we ever decide we do want to add such a flag.

Modify add_files_to_cache() and its helpers to accept the necessary
arguments instead of relying on globals.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/add.c

@@ -37,6 +37,8 @@ static int include_sparse;
 static const char *pathspec_from_file;
 
 struct update_callback_data {
+	struct index_state *index;
+	int include_sparse;
 	int flags;
 	int add_errors;
 };
@@ -100,7 +102,8 @@ static void update_callback(struct diff_queue_struct *q,
 		struct diff_filepair *p = q->queue[i];
 		const char *path = p->one->path;
 
-		if (!include_sparse && !path_in_sparse_checkout(path, &the_index))
+		if (!data->include_sparse &&
+		    !path_in_sparse_checkout(path, data->index))
 			continue;
 
 		switch (fix_unmerged_status(p, data)) {
@@ -108,7 +111,7 @@ static void update_callback(struct diff_queue_struct *q,
 			die(_("unexpected diff status %c"), p->status);
 		case DIFF_STATUS_MODIFIED:
 		case DIFF_STATUS_TYPE_CHANGED:
-			if (add_file_to_index(&the_index, path,	data->flags)) {
+			if (add_file_to_index(data->index, path, data->flags)) {
 				if (!(data->flags & ADD_CACHE_IGNORE_ERRORS))
 					die(_("updating files failed"));
 				data->add_errors++;
@@ -118,7 +121,7 @@ static void update_callback(struct diff_queue_struct *q,
 			if (data->flags & ADD_CACHE_IGNORE_REMOVAL)
 				break;
 			if (!(data->flags & ADD_CACHE_PRETEND))
-				remove_file_from_index(&the_index, path);
+				remove_file_from_index(data->index, path);
 			if (data->flags & (ADD_CACHE_PRETEND|ADD_CACHE_VERBOSE))
 				printf(_("remove '%s'\n"), path);
 			break;
@@ -126,16 +129,19 @@ static void update_callback(struct diff_queue_struct *q,
 	}
 }
 
-int add_files_to_cache(const char *prefix,
+int add_files_to_cache(struct repository *repo, const char *prefix,
-		       const struct pathspec *pathspec, int flags)
+		       const struct pathspec *pathspec, int include_sparse,
+		       int flags)
 {
 	struct update_callback_data data;
 	struct rev_info rev;
 
 	memset(&data, 0, sizeof(data));
+	data.index = repo->index;
+	data.include_sparse = include_sparse;
 	data.flags = flags;
 
-	repo_init_revisions(the_repository, &rev, prefix);
+	repo_init_revisions(repo, &rev, prefix);
 	setup_revisions(0, NULL, &rev, NULL);
 	if (pathspec)
 		copy_pathspec(&rev.prune_data, pathspec);
@@ -640,7 +646,9 @@ int cmd_add(int argc, const char **argv, const char *prefix)
 	if (add_renormalize)
 		exit_status |= renormalize_tracked_files(&pathspec, flags);
 	else
-		exit_status |= add_files_to_cache(prefix, &pathspec, flags);
+		exit_status |= add_files_to_cache(the_repository, prefix,
+						  &pathspec, include_sparse,
+						  flags);
 
 	if (add_new_files)
 		exit_status |= add_files(&dir, flags);

builtin/checkout.c

@@ -861,7 +861,7 @@ static int merge_working_tree(const struct checkout_opts *opts,
 			 * entries in the index.
 			 */
 
-			add_files_to_cache(NULL, NULL, 0);
+			add_files_to_cache(the_repository, NULL, NULL, 0, 0);
 			init_merge_options(&o, the_repository);
 			o.verbosity = 0;
 			work = write_in_core_index_as_tree(the_repository);

builtin/commit.c

@@ -447,7 +447,8 @@ static const char *prepare_index(const char **argv, const char *prefix,
 	if (all || (also && pathspec.nr)) {
 		repo_hold_locked_index(the_repository, &index_lock,
 				       LOCK_DIE_ON_ERROR);
-		add_files_to_cache(also ? prefix : NULL, &pathspec, 0);
+		add_files_to_cache(the_repository, also ? prefix : NULL,
+				   &pathspec, 0, 0);
 		refresh_cache_or_die(refresh_flags);
 		cache_tree_update(&the_index, WRITE_TREE_SILENT);
 		if (write_locked_index(&the_index, &index_lock, 0))

cache.h

@@ -554,7 +554,9 @@ int cmp_cache_name_compare(const void *a_, const void *b_);
  * return 0 if success, 1 - if addition of a file failed and
  * ADD_FILES_IGNORE_ERRORS was specified in flags
  */
-int add_files_to_cache(const char *prefix, const struct pathspec *pathspec, int flags);
+int add_files_to_cache(struct repository *repo, const char *prefix,
+		       const struct pathspec *pathspec, int include_sparse,
+		       int flags);
 
 /* diff.c */
 extern int diff_auto_refresh_index;