[PATCH] enable a timeout for hold_lock_file_for_update

[Martin Nicolay <m.nicolay@osm-ag.de>]

The new funktion get_files_lock_timeout_ms reads the config
core.fileslocktimeout analog get_files_ref_lock_timeout_ms.

This value is used in hold_lock_file_for_update instead of the
fixed value 0.
---
While working with complex scripts invoking git multiple times my
editor detects the changes and calls "git status". This leads to
aborts in "git-stash". With this patch and an appropriate value
core.fileslocktimeout this problem goes away.

 lockfile.c | 15 +++++++++++++++
 lockfile.h |  4 +++-
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/lockfile.c b/lockfile.c
index 8e8ab4f29f..ac19de8937 100644
--- a/lockfile.c
+++ b/lockfile.c
@@ -145,6 +145,21 @@ static int lock_file_timeout(struct lock_file *lk, const char *path,
 	}
 }
 
+long get_files_lock_timeout_ms(void)
+{
+	static int configured = 0;
+
+	/* The default timeout is 100 ms: */
+	static int timeout_ms = 100;
+
+	if (!configured) {
+		git_config_get_int("core.fileslocktimeout", &timeout_ms);
+		configured = 1;
+	}
+
+	return timeout_ms;
+}
+
 void unable_to_lock_message(const char *path, int err, struct strbuf *buf)
 {
 	if (err == EEXIST) {
diff --git a/lockfile.h b/lockfile.h
index 9843053ce8..a0520e6a7b 100644
--- a/lockfile.h
+++ b/lockfile.h
@@ -163,6 +163,8 @@ int hold_lock_file_for_update_timeout(
 		struct lock_file *lk, const char *path,
 		int flags, long timeout_ms);
 
+long get_files_lock_timeout_ms(void);
+
 /*
  * Attempt to create a lockfile for the file at `path` and return a
  * file descriptor for writing to it, or -1 on error. The flags
@@ -172,7 +174,7 @@ static inline int hold_lock_file_for_update(
 		struct lock_file *lk, const char *path,
 		int flags)
 {
-	return hold_lock_file_for_update_timeout(lk, path, flags, 0);
+	return hold_lock_file_for_update_timeout(lk, path, flags, get_files_lock_timeout_ms() );
 }
 
 /*
-- 
2.13.7