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[PATCH v4 14/23] log_ref_setup(): pass the open file descriptor back to the caller

From
Michael Haggerty <mhagger@alum.mit.edu>
Date
Jan 6, 2017, 16:22 UTC
Message-ID
<500171920606ec6b58b603882a98b8d47739ccb7.1483719289.git.mhagger@alum.mit.edu>
In-Reply-To
<cover.1483719289.git.mhagger@alum.mit.edu>

This function will most often be called by log_ref_write_1(), which wants to append to the reflog file. In that case, it is silly to close the file only for the caller to reopen it immediately. So, in the case that the file was opened, pass the open file descriptor back to the caller.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
---
 refs/files-backend.c | 39 ++++++++++++++++++++++-----------------
 1 file changed, 22 insertions(+), 17 deletions(-)
diff --git a/refs/files-backend.c b/refs/files-backend.c
index 27d4fd3..f723834 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -2719,19 +2719,23 @@ static int open_or_create_logfile(const char *path, void *cb)
 }
 
 /*
- * Create a reflog for a ref.  If force_create = 0, the reflog will
- * only be created for certain refs (those for which
- * should_autocreate_reflog returns non-zero.  Otherwise, create it
- * regardless of the ref name.  Fill in *err and return -1 on failure.
+ * Create a reflog for a ref. Store its path to *logfile. If
+ * force_create = 0, only create the reflog for certain refs (those
+ * for which should_autocreate_reflog returns non-zero). Otherwise,
+ * create it regardless of the reference name. If the logfile already
+ * existed or was created, return 0 and set *logfd to the file
+ * descriptor opened for appending to the file. If no logfile exists
+ * and we decided not to create one, return 0 and set *logfd to -1. On
+ * failure, fill in *err, set *logfd to -1, and return -1.
  */
-static int log_ref_setup(const char *refname, struct strbuf *logfile, struct strbuf *err, int force_create)
+static int log_ref_setup(const char *refname,
+			 struct strbuf *logfile, int *logfd,
+			 struct strbuf *err, int force_create)
 {
-	int logfd;
-
 	strbuf_git_path(logfile, "logs/%s", refname);
 
 	if (force_create || should_autocreate_reflog(refname)) {
-		if (raceproof_create_file(logfile->buf, open_or_create_logfile, &logfd)) {
+		if (raceproof_create_file(logfile->buf, open_or_create_logfile, logfd)) {
 			if (errno == ENOENT)
 				strbuf_addf(err, "unable to create directory for '%s': "
 					    "%s", logfile->buf, strerror(errno));
@@ -2745,8 +2749,8 @@ static int log_ref_setup(const char *refname, struct strbuf *logfile, struct str
 			return -1;
 		}
 	} else {
-		logfd = open(logfile->buf, O_APPEND | O_WRONLY, 0666);
-		if (logfd < 0) {
+		*logfd = open(logfile->buf, O_APPEND | O_WRONLY, 0666);
+		if (*logfd < 0) {
 			if (errno == ENOENT || errno == EISDIR) {
 				/*
 				 * The logfile doesn't already exist,
@@ -2763,10 +2767,8 @@ static int log_ref_setup(const char *refname, struct strbuf *logfile, struct str
 		}
 	}
 
-	if (logfd >= 0) {
+	if (*logfd >= 0)
 		adjust_shared_perm(logfile->buf);
-		close(logfd);
-	}
 
 	return 0;
 }
@@ -2777,11 +2779,14 @@ static int files_create_reflog(struct ref_store *ref_store,
 {
 	int ret;
 	struct strbuf sb = STRBUF_INIT;
+	int fd;
 
 	/* Check validity (but we don't need the result): */
 	files_downcast(ref_store, 0, "create_reflog");
 
-	ret = log_ref_setup(refname, &sb, err, force_create);
+	ret = log_ref_setup(refname, &sb, &fd, err, force_create);
+	if (fd >= 0)
+		close(fd);
 	strbuf_release(&sb);
 	return ret;
 }
@@ -2817,17 +2822,17 @@ static int log_ref_write_1(const char *refname, const unsigned char *old_sha1,
 			   struct strbuf *logfile, int flags,
 			   struct strbuf *err)
 {
-	int logfd, result, oflags = O_APPEND | O_WRONLY;
+	int logfd, result;
 
 	if (log_all_ref_updates < 0)
 		log_all_ref_updates = !is_bare_repository();
 
-	result = log_ref_setup(refname, logfile, err, flags & REF_FORCE_CREATE_REFLOG);
+	result = log_ref_setup(refname, logfile, &logfd, err,
+			       flags & REF_FORCE_CREATE_REFLOG);
 
 	if (result)
 		return result;
 
-	logfd = open(logfile->buf, oflags);
 	if (logfd < 0)
 		return 0;
 	result = log_ref_write_fd(logfd, old_sha1, new_sha1,
-- 
2.9.3
Previous: Michael HaggertyNext: Jeff King
Message 24 of 25 in “Delete directories left empty after ref deletion”
  1. 00/23 Delete directories left empty after ref deletionMichael Haggerty, Jan 6, 2017
  2. 01/23 files_rename_ref(): tidy up whitespaceMichael Haggerty, Jan 6, 2017
  3. 03/23 t5505: use "for-each-ref" to test for the non-existence of referencesMichael Haggerty, Jan 6, 2017
  4. 06/23 raceproof_create_file(): new functionMichael Haggerty, Jan 6, 2017
  5. 02/23 refname_is_safe(): correct docstringMichael Haggerty, Jan 6, 2017
  6. 05/23 safe_create_leading_directories(): set errno on SCLD_EXISTSMichael Haggerty, Jan 6, 2017
  7. 10/23 rename_tmp_log(): improve error reportingMichael Haggerty, Jan 6, 2017
  8. 09/23 rename_tmp_log(): use raceproof_create_file()Michael Haggerty, Jan 6, 2017
  9. 04/23 safe_create_leading_directories_const(): preserve errnoMichael Haggerty, Jan 6, 2017
  10. 07/23 lock_ref_sha1_basic(): inline constantMichael Haggerty, Jan 6, 2017
  11. 13/23 log_ref_setup(): improve robustness against racesMichael Haggerty, Jan 6, 2017
  12. 08/23 lock_ref_sha1_basic(): use raceproof_create_file()Michael Haggerty, Jan 6, 2017
  13. 11/23 log_ref_write(): inline functionMichael Haggerty, Jan 6, 2017
  14. 23/23 files_transaction_commit(): clean up empty directoriesMichael Haggerty, Jan 6, 2017
  15. 18/23 delete_ref_loose(): derive loose reference path from lockMichael Haggerty, Jan 6, 2017
  16. 19/23 delete_ref_loose(): inline functionMichael Haggerty, Jan 6, 2017
  17. 22/23 try_remove_empty_parents(): teach to remove parents of reflogs, tooMichael Haggerty, Jan 6, 2017
  18. 21/23 try_remove_empty_parents(): don't trash argument contentsMichael Haggerty, Jan 6, 2017
  19. 20/23 try_remove_empty_parents(): rename parameter "name" -> "refname"Michael Haggerty, Jan 6, 2017
  20. 16/23 log_ref_setup(): manage the name of the reflog file internallyMichael Haggerty, Jan 6, 2017
  21. 12/23 log_ref_setup(): separate code for create vs non-createMichael Haggerty, Jan 6, 2017
  22. 15/23 log_ref_write_1(): don't depend on logfile argumentMichael Haggerty, Jan 6, 2017
  23. 17/23 log_ref_write_1(): inline functionMichael Haggerty, Jan 6, 2017
  24. 14/23 log_ref_setup(): pass the open file descriptor back to the callerMichael Haggerty, Jan 6, 2017
  25. Jeff KingJan 6, 2017

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