editor: add a function to launch the sequence editor

As part of the rewrite of interactive rebase, the sequencer will need to
open the sequence editor to allow the user to edit the todo list.
Instead of duplicating the existing launch_editor() function, this
refactors it to a new function, launch_specified_editor(), which takes
the editor as a parameter, in addition to the path, the buffer and the
environment variables.  launch_sequence_editor() is then added to launch
the sequence editor.

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

1 files changed, 2 insertions, 0 deletions

diff --git a/strbuf.h b/strbuf.h
index 60a35ae..66da982 100644
--- a/strbuf.h
+++ b/strbuf.h
@@ -575,6 +575,8 @@ extern void strbuf_add_unique_abbrev(struct strbuf *sb,
  * file's contents are not read into the buffer upon completion.
  */
 extern int launch_editor(const char *path, struct strbuf *buffer, const char *const *env);
+extern int launch_sequence_editor(const char *path, struct strbuf *buffer,
+				  const char *const *env);
 
 extern void strbuf_add_lines(struct strbuf *sb, const char *prefix, const char *buf, size_t size);