rebase -i: refactor transform_todo_ids

The transform_todo_ids function is a little hard to read. Lets try
to make it easier by using more of the strbuf API. Also, since we'll
soon be adding command abbreviations, let's rename the function so
it's name reflects that change.

Signed-off-by: Liam Beguin <liambeguin@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

3 files changed, 31 insertions, 44 deletions

diff --git a/builtin/rebase--helper.c b/builtin/rebase--helper.c
index f8519363a3..8ad4779d16 100644
--- a/builtin/rebase--helper.c
+++ b/builtin/rebase--helper.c
@@ -55,9 +55,9 @@ int cmd_rebase__helper(int argc, const char **argv, const char *prefix)
 	if (command == MAKE_SCRIPT && argc > 1)
 		return !!sequencer_make_script(keep_empty, stdout, argc, argv);
 	if (command == SHORTEN_SHA1S && argc == 1)
-		return !!transform_todo_ids(1);
+		return !!transform_todos(1);
 	if (command == EXPAND_SHA1S && argc == 1)
-		return !!transform_todo_ids(0);
+		return !!transform_todos(0);
 	if (command == CHECK_TODO_LIST && argc == 1)
 		return !!check_todo_list();
 	if (command == SKIP_UNNECESSARY_PICKS && argc == 1)
diff --git a/sequencer.c b/sequencer.c
index 5033b049d9..c9a661a8c4 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -2494,60 +2494,47 @@ int sequencer_make_script(int keep_empty, FILE *out,
 }
 
 
-int transform_todo_ids(int shorten_ids)
+int transform_todos(int shorten_ids)
 {
 	const char *todo_file = rebase_path_todo();
 	struct todo_list todo_list = TODO_LIST_INIT;
-	int fd, res, i;
-	FILE *out;
+	struct strbuf buf = STRBUF_INIT;
+	struct todo_item *item;
+	int i;
 
-	strbuf_reset(&todo_list.buf);
-	fd = open(todo_file, O_RDONLY);
-	if (fd < 0)
-		return error_errno(_("could not open '%s'"), todo_file);
-	if (strbuf_read(&todo_list.buf, fd, 0) < 0) {
-		close(fd);
+	if (strbuf_read_file(&todo_list.buf, todo_file, 0) < 0)
 		return error(_("could not read '%s'."), todo_file);
-	}
-	close(fd);
 
-	res = parse_insn_buffer(todo_list.buf.buf, &todo_list);
-	if (res) {
+	if (parse_insn_buffer(todo_list.buf.buf, &todo_list)) {
 		todo_list_release(&todo_list);
 		return error(_("unusable todo list: '%s'"), todo_file);
 	}
 
-	out = fopen(todo_file, "w");
-	if (!out) {
-		todo_list_release(&todo_list);
-		return error(_("unable to open '%s' for writing"), todo_file);
-	}
-	for (i = 0; i < todo_list.nr; i++) {
-		struct todo_item *item = todo_list.items + i;
-		int bol = item->offset_in_buf;
-		const char *p = todo_list.buf.buf + bol;
-		int eol = i + 1 < todo_list.nr ?
-			todo_list.items[i + 1].offset_in_buf :
-			todo_list.buf.len;
-
-		if (item->command >= TODO_EXEC && item->command != TODO_DROP)
-			fwrite(p, eol - bol, 1, out);
-		else {
-			const char *id = shorten_ids ?
-				short_commit_name(item->commit) :
-				oid_to_hex(&item->commit->object.oid);
-			int len;
-
-			p += strspn(p, " \t"); /* left-trim command */
-			len = strcspn(p, " \t"); /* length of command */
-
-			fprintf(out, "%.*s %s %.*s\n",
-				len, p, id, item->arg_len, item->arg);
+	for (item = todo_list.items, i = 0; i < todo_list.nr; i++, item++) {
+		/* if the item is not a command write it and continue */
+		if (item->command >= TODO_COMMENT) {
+			strbuf_addf(&buf, "%.*s\n", item->arg_len, item->arg);
+			continue;
+		}
+
+		/* add command to the buffer */
+		strbuf_addstr(&buf, command_to_string(item->command));
+
+		/* add commit id */
+		if (item->commit) {
+			const char *oid = shorten_ids ?
+					  short_commit_name(item->commit) :
+					  oid_to_hex(&item->commit->object.oid);
+
+			strbuf_addf(&buf, " %s", oid);
 		}
+		/* add all the rest */
+		strbuf_addf(&buf, " %.*s\n", item->arg_len, item->arg);
 	}
-	fclose(out);
+
+	i = write_message(buf.buf, buf.len, todo_file, 0);
 	todo_list_release(&todo_list);
-	return 0;
+	return i;
 }
 
 enum check_level {
diff --git a/sequencer.h b/sequencer.h
index 6f3d3df82c..4f7f2c93f8 100644
--- a/sequencer.h
+++ b/sequencer.h
@@ -48,7 +48,7 @@ int sequencer_remove_state(struct replay_opts *opts);
 int sequencer_make_script(int keep_empty, FILE *out,
 		int argc, const char **argv);
 
-int transform_todo_ids(int shorten_ids);
+int transform_todos(int shorten_ids);
 int check_todo_list(void);
 int skip_unnecessary_picks(void);
 int rearrange_squash(void);