Merge branch 'jh/fsck-promisors'

In preparation for implementing narrow/partial clone, the machinery
for checking object connectivity used by gc and fsck has been
taught that a missing object is OK when it is referenced by a
packfile specially marked as coming from trusted repository that
promises to make them available on-demand and lazily.

* jh/fsck-promisors:
  gc: do not repack promisor packfiles
  rev-list: support termination at promisor objects
  sha1_file: support lazily fetching missing objects
  introduce fetch-object: fetch one promisor object
  index-pack: refactor writing of .keep files
  fsck: support promisor objects as CLI argument
  fsck: support referenced promisor objects
  fsck: support refs pointing to promisor objects
  fsck: introduce partialclone extension
  extension.partialclone: introduce partial clone extension

1 files changed, 27 insertions, 0 deletions

diff --git a/fetch-object.c b/fetch-object.c
new file mode 100644
index 0000000000..258fcfac75
--- /dev/null
+++ b/fetch-object.c
@@ -0,0 +1,27 @@
+#include "cache.h"
+#include "packfile.h"
+#include "pkt-line.h"
+#include "strbuf.h"
+#include "transport.h"
+#include "fetch-object.h"
+
+void fetch_object(const char *remote_name, const unsigned char *sha1)
+{
+	struct remote *remote;
+	struct transport *transport;
+	struct ref *ref;
+	int original_fetch_if_missing = fetch_if_missing;
+
+	fetch_if_missing = 0;
+	remote = remote_get(remote_name);
+	if (!remote->url[0])
+		die(_("Remote with no URL"));
+	transport = transport_get(remote, remote->url[0]);
+
+	ref = alloc_ref(sha1_to_hex(sha1));
+	hashcpy(ref->old_oid.hash, sha1);
+	transport_set_option(transport, TRANS_OPT_FROM_PROMISOR, "1");
+	transport_set_option(transport, TRANS_OPT_NO_DEPENDENTS, "1");
+	transport_fetch_refs(transport, ref);
+	fetch_if_missing = original_fetch_if_missing;
+}