sequencer: make sequencer_make_script() write its script to a strbuf

This makes sequencer_make_script() write its script to a strbuf (ie. the
buffer of a todo_list) instead of a FILE.  This reduce the amount of
read/write made by rebase interactive.

Signed-off-by: Alban Gruin <alban.gruin@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

3 files changed, 28 insertions, 31 deletions

diff --git a/builtin/rebase--interactive.c b/builtin/rebase--interactive.c
index 60b15f9693..b4190e58e1 100644
--- a/builtin/rebase--interactive.c
+++ b/builtin/rebase--interactive.c
@@ -71,7 +71,8 @@ static int do_interactive_rebase(struct replay_opts *opts, unsigned flags,
 	const char *head_hash = NULL;
 	char *revisions = NULL, *shortrevisions = NULL;
 	struct argv_array make_script_args = ARGV_ARRAY_INIT;
-	FILE *todo_list;
+	FILE *todo_list_file;
+	struct todo_list todo_list = TODO_LIST_INIT;
 
 	if (prepare_branch_to_be_rebased(opts, switch_to))
 		return -1;
@@ -93,8 +94,8 @@ static int do_interactive_rebase(struct replay_opts *opts, unsigned flags,
 	if (!upstream && squash_onto)
 		write_file(path_squash_onto(), "%s\n", squash_onto);
 
-	todo_list = fopen(rebase_path_todo(), "w");
-	if (!todo_list) {
+	todo_list_file = fopen(rebase_path_todo(), "w");
+	if (!todo_list_file) {
 		free(revisions);
 		free(shortrevisions);
 
@@ -105,10 +106,11 @@ static int do_interactive_rebase(struct replay_opts *opts, unsigned flags,
 	if (restrict_revision)
 		argv_array_push(&make_script_args, restrict_revision);
 
-	ret = sequencer_make_script(the_repository, todo_list,
+	ret = sequencer_make_script(the_repository, &todo_list.buf,
 				    make_script_args.argc, make_script_args.argv,
 				    flags);
-	fclose(todo_list);
+	fputs(todo_list.buf.buf, todo_list_file);
+	fclose(todo_list_file);
 
 	if (ret)
 		error(_("could not generate todo list"));
@@ -121,6 +123,7 @@ static int do_interactive_rebase(struct replay_opts *opts, unsigned flags,
 
 	free(revisions);
 	free(shortrevisions);
+	todo_list_release(&todo_list);
 	argv_array_clear(&make_script_args);
 
 	return ret;
diff --git a/sequencer.c b/sequencer.c
index 7798f93b23..cf716fa5b8 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -4215,7 +4215,7 @@ static const char *label_oid(struct object_id *oid, const char *label,
 }
 
 static int make_script_with_merges(struct pretty_print_context *pp,
-				   struct rev_info *revs, FILE *out,
+				   struct rev_info *revs, struct strbuf *out,
 				   unsigned flags)
 {
 	int keep_empty = flags & TODO_LIST_KEEP_EMPTY;
@@ -4360,7 +4360,7 @@ static int make_script_with_merges(struct pretty_print_context *pp,
 	 * gathering commits not yet shown, reversing the list on the fly,
 	 * then outputting that list (labeling revisions as needed).
 	 */
-	fprintf(out, "%s onto\n", cmd_label);
+	strbuf_addf(out, "%s onto\n", cmd_label);
 	for (iter = tips; iter; iter = iter->next) {
 		struct commit_list *list = NULL, *iter2;
 
@@ -4370,9 +4370,9 @@ static int make_script_with_merges(struct pretty_print_context *pp,
 		entry = oidmap_get(&state.commit2label, &commit->object.oid);
 
 		if (entry)
-			fprintf(out, "\n%c Branch %s\n", comment_line_char, entry->string);
+			strbuf_addf(out, "\n%c Branch %s\n", comment_line_char, entry->string);
 		else
-			fprintf(out, "\n");
+			strbuf_addch(out, '\n');
 
 		while (oidset_contains(&interesting, &commit->object.oid) &&
 		       !oidset_contains(&shown, &commit->object.oid)) {
@@ -4385,8 +4385,8 @@ static int make_script_with_merges(struct pretty_print_context *pp,
 		}
 
 		if (!commit)
-			fprintf(out, "%s %s\n", cmd_reset,
-				rebase_cousins ? "onto" : "[new root]");
+			strbuf_addf(out, "%s %s\n", cmd_reset,
+				    rebase_cousins ? "onto" : "[new root]");
 		else {
 			const char *to = NULL;
 
@@ -4399,12 +4399,12 @@ static int make_script_with_merges(struct pretty_print_context *pp,
 					       &state);
 
 			if (!to || !strcmp(to, "onto"))
-				fprintf(out, "%s onto\n", cmd_reset);
+				strbuf_addf(out, "%s onto\n", cmd_reset);
 			else {
 				strbuf_reset(&oneline);
 				pretty_print_commit(pp, commit, &oneline);
-				fprintf(out, "%s %s # %s\n",
-					cmd_reset, to, oneline.buf);
+				strbuf_addf(out, "%s %s # %s\n",
+					    cmd_reset, to, oneline.buf);
 			}
 		}
 
@@ -4413,11 +4413,11 @@ static int make_script_with_merges(struct pretty_print_context *pp,
 			entry = oidmap_get(&commit2todo, oid);
 			/* only show if not already upstream */
 			if (entry)
-				fprintf(out, "%s\n", entry->string);
+				strbuf_addf(out, "%s\n", entry->string);
 			entry = oidmap_get(&state.commit2label, oid);
 			if (entry)
-				fprintf(out, "%s %s\n",
-					cmd_label, entry->string);
+				strbuf_addf(out, "%s %s\n",
+					    cmd_label, entry->string);
 			oidset_insert(&shown, oid);
 		}
 
@@ -4439,13 +4439,11 @@ static int make_script_with_merges(struct pretty_print_context *pp,
 	return 0;
 }
 
-int sequencer_make_script(struct repository *r, FILE *out,
-			  int argc, const char **argv,
-			  unsigned flags)
+int sequencer_make_script(struct repository *r, struct strbuf *out, int argc,
+			  const char **argv, unsigned flags)
 {
 	char *format = NULL;
 	struct pretty_print_context pp = {0};
-	struct strbuf buf = STRBUF_INIT;
 	struct rev_info revs;
 	struct commit *commit;
 	int keep_empty = flags & TODO_LIST_KEEP_EMPTY;
@@ -4488,16 +4486,13 @@ int sequencer_make_script(struct repository *r, FILE *out,
 
 		if (!is_empty && (commit->object.flags & PATCHSAME))
 			continue;
-		strbuf_reset(&buf);
 		if (!keep_empty && is_empty)
-			strbuf_addf(&buf, "%c ", comment_line_char);
-		strbuf_addf(&buf, "%s %s ", insn,
+			strbuf_addf(out, "%c ", comment_line_char);
+		strbuf_addf(out, "%s %s ", insn,
 			    oid_to_hex(&commit->object.oid));
-		pretty_print_commit(&pp, commit, &buf);
-		strbuf_addch(&buf, '\n');
-		fputs(buf.buf, out);
+		pretty_print_commit(&pp, commit, out);
+		strbuf_addch(out, '\n');
 	}
-	strbuf_release(&buf);
 	return 0;
 }
 
diff --git a/sequencer.h b/sequencer.h
index add50f04f1..e25f5151d3 100644
--- a/sequencer.h
+++ b/sequencer.h
@@ -142,9 +142,8 @@ int sequencer_remove_state(struct replay_opts *opts);
 #define TODO_LIST_REBASE_COUSINS (1U << 4)
 #define TODO_LIST_APPEND_TODO_HELP (1U << 5)
 
-int sequencer_make_script(struct repository *r, FILE *out, int argc,
-			  const char **argv,
-			  unsigned flags);
+int sequencer_make_script(struct repository *r, struct strbuf *out, int argc,
+			  const char **argv, unsigned flags);
 
 int sequencer_add_exec_commands(struct repository *r,
 				struct string_list *commands);