[PATCH] preserve mtime of local clone

[Clemens Buchacher <drizzd@aon.at>]

A local clone without hardlinks copies all objects, including dangling
ones, to the new repository. Since the mtimes are renewed, those
dangling objects cannot be pruned by "git gc --prune", even if they
would have been old enough for pruning in the original repository.

Instead, preserve mtime during copy. "git gc --prune" will then work
in the clone just like it did in the original.

Signed-off-by: Clemens Buchacher <drizzd@aon.at>
---

On Sat, Sep 12, 2009 at 10:26:24AM +0200, Clemens Buchacher wrote:

> If it's a problem we can use utime() instead. I was just trying to use the
> file descriptors, since they were available. But the patch would be a little
> smaller if I didn't touch copy_fd().

Here we go.

 builtin-clone.c   |    2 +-
 builtin-init-db.c |    2 +-
 cache.h           |    4 +++-
 copy.c            |   18 +++++++++++++++++-
 rerere.c          |    2 +-
 5 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/builtin-clone.c b/builtin-clone.c
index ad04808..cb3c895 100644
--- a/builtin-clone.c
+++ b/builtin-clone.c
@@ -269,7 +269,7 @@ static void copy_or_link_directory(struct strbuf *src, struct strbuf *dest)
 				die_errno("failed to create link '%s'", dest->buf);
 			option_no_hardlinks = 1;
 		}
-		if (copy_file(dest->buf, src->buf, 0666))
+		if (copy_file(dest->buf, src->buf, 0666, 1))
 			die_errno("failed to copy file to '%s'", dest->buf);
 	}
 	closedir(dir);
diff --git a/builtin-init-db.c b/builtin-init-db.c
index dd84cae..5deb81d 100644
--- a/builtin-init-db.c
+++ b/builtin-init-db.c
@@ -100,7 +100,7 @@ static void copy_templates_1(char *path, int baselen,
 				die_errno("cannot symlink '%s' '%s'", lnk, path);
 		}
 		else if (S_ISREG(st_template.st_mode)) {
-			if (copy_file(path, template, st_template.st_mode))
+			if (copy_file(path, template, st_template.st_mode, 0))
 				die_errno("cannot copy '%s' to '%s'", template,
 					  path);
 		}
diff --git a/cache.h b/cache.h
index 5fad24c..ac692d0 100644
--- a/cache.h
+++ b/cache.h
@@ -922,7 +922,9 @@ extern const char *git_mailmap_file;
 /* IO helper functions */
 extern void maybe_flush_or_die(FILE *, const char *);
 extern int copy_fd(int ifd, int ofd);
-extern int copy_file(const char *dst, const char *src, int mode);
+extern int copy_file(const char *dst, const char *src, int mode, int
+		preserve_times);
+extern int copy_times(const char *dst, const char *src);
 extern ssize_t read_in_full(int fd, void *buf, size_t count);
 extern ssize_t write_in_full(int fd, const void *buf, size_t count);
 extern void write_or_die(int fd, const void *buf, size_t count);
diff --git a/copy.c b/copy.c
index e54d15a..fb5e946 100644
--- a/copy.c
+++ b/copy.c
@@ -35,7 +35,21 @@ int copy_fd(int ifd, int ofd)
 	return 0;
 }
 
-int copy_file(const char *dst, const char *src, int mode)
+int copy_times(const char *dst, const char *src)
+{
+	struct stat st;
+	struct utimbuf times;
+	if (stat(src, &st) < 0)
+		return -1;
+	times.actime = st.st_atime;
+	times.modtime = st.st_mtime;
+	if (utime(dst, &times) < 0)
+		return -1;
+	return 0;
+}
+
+int copy_file(const char *dst, const char *src, int mode,
+		int preserve_times)
 {
 	int fdi, fdo, status;
 
@@ -52,6 +66,8 @@ int copy_file(const char *dst, const char *src, int mode)
 
 	if (!status && adjust_shared_perm(dst))
 		return -1;
+	if (!status && preserve_times && copy_times(dst, src))
+		return -1;
 
 	return status;
 }
diff --git a/rerere.c b/rerere.c
index 87360dc..d25f5f1 100644
--- a/rerere.c
+++ b/rerere.c
@@ -326,7 +326,7 @@ static int do_plain_rerere(struct string_list *rr, int fd)
 			continue;
 
 		fprintf(stderr, "Recorded resolution for '%s'.\n", path);
-		copy_file(rerere_path(name, "postimage"), path, 0666);
+		copy_file(rerere_path(name, "postimage"), path, 0666, 0);
 	mark_resolved:
 		rr->items[i].util = NULL;
 	}
-- 
1.6.5.rc0.164.g5f6b0