The write_message() function safely writes an strbuf to a file.
Sometimes it is inconvenient to require an strbuf, though: the text to
be written may not be stored in a strbuf, or the strbuf should not be
released after writing.
Let's refactor "safely writing string to a file" into
write_with_lock_file(), and make write_message() use it. The new
function makes it easy to create new convenience function
write_file_gently(); as some of the upcoming callers of this new
function would want to append a newline character, add a flag for it in
write_file_gently(), and thus in write_with_lock_file().
While at it, roll back the locked files in case of failure, as pointed
out by Hannes Sixt.
Signed-off-by: Johannes Schindelin <johannes.schindelin@xxxxxx>
---
sequencer.c | 31 ++++++++++++++++++++++++++-----
1 file changed, 26 insertions(+), 5 deletions(-)
diff --git a/sequencer.c b/sequencer.c
index 45a3651..5cca8d8 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -234,22 +234,43 @@ static void print_advice(int show_hint, struct replay_opts *opts)
}
}
-static int write_message(struct strbuf *msgbuf, const char *filename)
+static int write_with_lock_file(const char *filename,
+ const void *buf, size_t len, int append_eol)
{
static struct lock_file msg_file;
int msg_fd = hold_lock_file_for_update(&msg_file, filename, 0);
if (msg_fd < 0)
return error_errno(_("Could not lock '%s'"), filename);
- if (write_in_full(msg_fd, msgbuf->buf, msgbuf->len) < 0)
- return error_errno(_("Could not write to %s"), filename);
- strbuf_release(msgbuf);
- if (commit_lock_file(&msg_file) < 0)
+ if (write_in_full(msg_fd, buf, len) < 0) {
+ rollback_lock_file(&msg_file);
+ return error_errno(_("Could not write to '%s'"), filename);
+ }
+ if (append_eol && write(msg_fd, "\n", 1) < 0) {
+ rollback_lock_file(&msg_file);
+ return error_errno(_("Could not write eol to '%s"), filename);
+ }
+ if (commit_lock_file(&msg_file) < 0) {
+ rollback_lock_file(&msg_file);
return error(_("Error wrapping up %s."), filename);
+ }
return 0;
}
+static int write_message(struct strbuf *msgbuf, const char *filename)
+{
+ int res = write_with_lock_file(filename, msgbuf->buf, msgbuf->len, 0);
+ strbuf_release(msgbuf);
+ return res;
+}
+
+static int write_file_gently(const char *filename,
+ const char *text, int append_eol)
+{
+ return write_with_lock_file(filename, text, strlen(text), append_eol);
+}
+
/*
* Reads a file that was presumably written by a shell script, i.e.
* with an end-of-line marker that needs to be stripped.
--
2.10.0.windows.1.325.ge6089c1