[ostree] core: Set mtime of content objects to 0

[Colin Walters <walters src gnome org>]

commit fe5ed36461a52b38cb366162bfd222ad3b326bf2
Author: Roddy Shuler <roddy endlessm com>
Date:   Thu Dec 12 14:56:19 2013 -0800

    core: Set mtime of content objects to 0
    
    This is necessary to satisfy tools such as guile and python, which
    compare mtimes to determine whether or not source files need to be
    compiled.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=720363

 src/libostree/ostree-repo-commit.c |   18 ++++++++++++++++++
 tests/test-basic.sh                |    7 +++++++
 2 files changed, 25 insertions(+), 0 deletions(-)
---
diff --git a/src/libostree/ostree-repo-commit.c b/src/libostree/ostree-repo-commit.c
index 4fc46c3..caa5103 100644
--- a/src/libostree/ostree-repo-commit.c
+++ b/src/libostree/ostree-repo-commit.c
@@ -100,6 +100,7 @@ commit_loose_object_trusted (OstreeRepo        *self,
     {
       int fd;
       int res;
+      struct timespec times[2];
 
       g_assert (temp_out != NULL);
 
@@ -134,6 +135,23 @@ commit_loose_object_trusted (OstreeRepo        *self,
               if (!gs_fd_set_all_xattrs (fd, xattrs, cancellable, error))
                 goto out;
             }
+
+          /* To satisfy tools such as guile which compare mtimes
+           * to determine whether or not source files need to be compiled,
+           * set the modification time to 0.
+           */
+          times[0].tv_sec = 0; /* atime */
+          times[0].tv_nsec = UTIME_OMIT;
+          times[1].tv_sec = 0; /* mtime */
+          times[1].tv_nsec = 0;
+          do
+            res = futimens (fd, times);
+          while (G_UNLIKELY (res == -1 && errno == EINTR));
+          if (G_UNLIKELY (res == -1))
+            {
+              ot_util_set_error_from_errno (error, errno);
+              goto out;
+            }
         }
 
       /* Ensure that in case of a power cut, these files have the data we
diff --git a/tests/test-basic.sh b/tests/test-basic.sh
index dd6103b..2ac197f 100755
--- a/tests/test-basic.sh
+++ b/tests/test-basic.sh
@@ -310,3 +310,10 @@ ${CMD_PREFIX} ostree --repo=repo remote show-url aremote > aremote-url.txt
 assert_file_has_content aremote-url.txt 'http.*remote\.example\.com/repo'
 echo "ok remote show-url"
 
+cd ${test_tmpdir}
+rm -rf test2-checkout
+$OSTREE checkout test2 test2-checkout
+stat '--format=%Y' test2-checkout/baz/cow > cow-mtime
+assert_file_has_content cow-mtime 0
+echo "ok content mtime"
+