rebase -i -x: add exec commands via the rebase--helper

Recent work on `git-rebase--interactive` aims to convert shell code to
C. Even if this is most likely not a big performance enhancement, let's
convert it too since a coming change to abbreviate command names
requires it to be updated.

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

builtin/rebase--helper.c

@@ -15,7 +15,8 @@ int cmd_rebase__helper(int argc, const char **argv, const char *prefix)
 	unsigned flags = 0, keep_empty = 0;
 	enum {
 		CONTINUE = 1, ABORT, MAKE_SCRIPT, SHORTEN_OIDS, EXPAND_OIDS,
-		CHECK_TODO_LIST, SKIP_UNNECESSARY_PICKS, REARRANGE_SQUASH
+		CHECK_TODO_LIST, SKIP_UNNECESSARY_PICKS, REARRANGE_SQUASH,
+		ADD_EXEC
 	} command = 0;
 	struct option options[] = {
 		OPT_BOOL(0, "ff", &opts.allow_ff, N_("allow fast-forward")),
@@ -36,6 +37,8 @@ int cmd_rebase__helper(int argc, const char **argv, const char *prefix)
 			N_("skip unnecessary picks"), SKIP_UNNECESSARY_PICKS),
 		OPT_CMDMODE(0, "rearrange-squash", &command,
 			N_("rearrange fixup/squash lines"), REARRANGE_SQUASH),
+		OPT_CMDMODE(0, "add-exec-commands", &command,
+			N_("insert exec commands in todo list"), ADD_EXEC),
 		OPT_END()
 	};
 
@@ -65,5 +68,7 @@ int cmd_rebase__helper(int argc, const char **argv, const char *prefix)
 		return !!skip_unnecessary_picks();
 	if (command == REARRANGE_SQUASH && argc == 1)
 		return !!rearrange_squash();
+	if (command == ADD_EXEC && argc == 2)
+		return !!sequencer_add_exec_commands(argv[1]);
 	usage_with_options(builtin_rebase_helper_usage, options);
 }

git-rebase--interactive.sh

@@ -722,27 +722,6 @@ collapse_todo_ids() {
 	git rebase--helper --shorten-ids
 }
 
-# Add commands after a pick or after a squash/fixup series
-# in the todo list.
-add_exec_commands () {
-	{
-		first=t
-		while read -r insn rest
-		do
-			case $insn in
-			pick)
-				test -n "$first" ||
-				printf "%s" "$cmd"
-				;;
-			esac
-			printf "%s %s\n" "$insn" "$rest"
-			first=
-		done
-		printf "%s" "$cmd"
-	} <"$1" >"$1.new" &&
-	mv "$1.new" "$1"
-}
-
 # Switch to the branch in $into and notify it in the reflog
 checkout_onto () {
 	GIT_REFLOG_ACTION="$GIT_REFLOG_ACTION: checkout $onto_name"
@@ -982,7 +961,7 @@ fi
 
 test -s "$todo" || echo noop >> "$todo"
 test -z "$autosquash" || git rebase--helper --rearrange-squash || exit
-test -n "$cmd" && add_exec_commands "$todo"
+test -n "$cmd" && git rebase--helper --add-exec-commands "$cmd"
 
 todocount=$(git stripspace --strip-comments <"$todo" | wc -l)
 todocount=${todocount##* }

sequencer.c

@@ -2494,6 +2494,45 @@ 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)
+{
+	const char *todo_file = rebase_path_todo();
+	struct todo_list todo_list = TODO_LIST_INIT;
+	struct todo_item *item;
+	struct strbuf *buf = &todo_list.buf;
+	size_t offset = 0, commands_len = strlen(commands);
+	int i, first;
+
+	if (strbuf_read_file(&todo_list.buf, todo_file, 0) < 0)
+		return error(_("could not read '%s'."), todo_file);
+
+	if (parse_insn_buffer(todo_list.buf.buf, &todo_list)) {
+		todo_list_release(&todo_list);
+		return error(_("unusable todo list: '%s'"), todo_file);
+	}
+
+	first = 1;
+	/* insert <commands> before every pick except the first one */
+	for (item = todo_list.items, i = 0; i < todo_list.nr; i++, item++) {
+		if (item->command == TODO_PICK && !first) {
+			strbuf_insert(buf, item->offset_in_buf + offset,
+				      commands, commands_len);
+			offset += commands_len;
+		}
+		first = 0;
+	}
+
+	/* append final <commands> */
+	strbuf_add(buf, commands, commands_len);
+
+	i = write_message(buf->buf, buf->len, todo_file, 0);
+	todo_list_release(&todo_list);
+	return i;
+}
 
 int transform_todos(unsigned flags)
 {

sequencer.h

@@ -50,6 +50,7 @@ int sequencer_remove_state(struct replay_opts *opts);
 int sequencer_make_script(FILE *out, int argc, const char **argv,
 			  unsigned flags);
 
+int sequencer_add_exec_commands(const char *command);
 int transform_todos(unsigned flags);
 int check_todo_list(void);
 int skip_unnecessary_picks(void);