[PATCH v4 20/25] sequencer: refactor write_message()
- From
Johannes Schindelin <johannes.schindelin@gmx.de>
- Date
- Oct 14, 2016, 13:18 UTC
- Message-ID
- <9a66d53ebd86d35136597e534be03605bb1346bc.1476450940.git.johannes.schindelin@gmx.de>
- In-Reply-To
- <cover.1476450940.git.johannes.schindelin@gmx.de>
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 will make it easy to create a new convenience function write_file_gently() that does not die(); as some of the upcoming callers of this new function will want to append a newline character, we already add that flag as parameter to 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@gmx.de> --- sequencer.c | 25 ++++++++++++++++++++----- 1 file changed, 20 insertions(+), 5 deletions(-)
diff --git a/sequencer.c b/sequencer.c index 914a576..baccee9 100644 --- a/sequencer.c +++ b/sequencer.c @@ -234,22 +234,37 @@ 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; +} + /* * Reads a file that was presumably written by a shell script, i.e. * with an end-of-line marker that needs to be stripped.
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