Re: [PATCH 04/15] sequencer: refactor sequencer_add_exec_commands() to work on a todo_list

This refactors sequencer_add_exec_commands() to work on a todo_list to
avoid redundant reads and writes to the disk.

sequencer_add_exec_commands() still reads the todo list from the disk,
as it is needed by rebase -p.  todo_list_add_exec_commands() works on a
todo_list structure, and reparses it at the end.

Signed-off-by: Alban Gruin <redacted>
---
  sequencer.c | 56 +++++++++++++++++++++++++++++++----------------------
  1 file changed, 33 insertions(+), 23 deletions(-)

diff --git a/sequencer.c b/sequencer.c
index 8dda61927c..6d998f21a4 100644
--- a/sequencer.c
+++ b/sequencer.c

@@ -4370,34 +4370,21 @@ int sequencer_make_script(FILE *out, int argc, const char **argv,
  	return 0;
  }
  
-/*
- * Add commands after pick and (series of) squash/fixup commands
- * in the todo list.
- */
-int sequencer_add_exec_commands(const char *commands)
+static void todo_list_add_exec_commands(struct todo_list *todo_list,
+					const char *commands)
  {
-	const char *todo_file = rebase_path_todo();
-	struct todo_list todo_list = TODO_LIST_INIT;
-	struct strbuf *buf = &todo_list.buf;
+	struct strbuf *buf = &todo_list->buf;
  	size_t offset = 0, commands_len = strlen(commands);
  	int i, insert;
  
-	if (strbuf_read_file(&todo_list.buf, todo_file, 0) < 0)
-		return error(_("could not read '%s'."), todo_file);
-
-	if (todo_list_parse_insn_buffer(todo_list.buf.buf, &todo_list)) {
-		todo_list_release(&todo_list);
-		return error(_("unusable todo list: '%s'"), todo_file);
-	}
-
  	/*
  	 * Insert <commands> after every pick. Here, fixup/squash chains
  	 * are considered part of the pick, so we insert the commands *after*
  	 * those chains if there are any.
  	 */
  	insert = -1;
-	for (i = 0; i < todo_list.nr; i++) {
-		enum todo_command command = todo_list.items[i].command;
+	for (i = 0; i < todo_list->nr; i++) {
+		enum todo_command command = todo_list->items[i].command;
  
  		if (insert >= 0) {
  			/* skip fixup/squash chains */

@@ -4408,7 +4395,7 @@ int sequencer_add_exec_commands(const char *commands)
  				continue;
  			}
  			strbuf_insert(buf,
-				      todo_list.items[insert].offset_in_buf +
+				      todo_list->items[insert].offset_in_buf +
  				      offset, commands, commands_len);
  			offset += commands_len;
  			insert = -1;

@@ -4419,15 +4406,38 @@ int sequencer_add_exec_commands(const char *commands)
  	}
  
  	/* insert or append final <commands> */
-	if (insert >= 0 && insert < todo_list.nr)
-		strbuf_insert(buf, todo_list.items[insert].offset_in_buf +
+	if (insert >= 0 && insert < todo_list->nr)
+		strbuf_insert(buf, todo_list->items[insert].offset_in_buf +
  			      offset, commands, commands_len);
  	else if (insert >= 0 || !offset)
  		strbuf_add(buf, commands, commands_len);
  
-	i = write_message(buf->buf, buf->len, todo_file, 0);
+	if (todo_list_parse_insn_buffer(buf->buf, todo_list))
+		BUG("unusable todo list");}