clone: request the 'bundle-uri' command when available

Set up all the needed client parts of the 'bundle-uri' protocol v2
command, without actually doing anything with the bundle URIs.

If the server says it supports 'bundle-uri' teach Git to issue the
'bundle-uri' command after the 'ls-refs' during 'git clone'. The
returned key=value pairs are passed to the bundle list code which is
tested using a different ingest mechanism in t5750-bundle-uri-parse.sh.

At this point, Git does nothing with that bundle list. It will not
download any of the bundles. That will come in a later change after
these protocol bits are finalized.

The no-op client is initially used only by 'git clone' to test the basic
functionality, and eventually will bootstrap the initial download of Git
objects during a fresh clone. The bundle URI client will not be
integrated into other fetches until a mechanism is created to select a
subset of bundles for download.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 19 insertions, 0 deletions

diff --git a/transport.h b/transport.h
index b5bf7b3e70..85150f504f 100644
--- a/transport.h
+++ b/transport.h
@@ -62,6 +62,7 @@ enum transport_family {
 	TRANSPORT_FAMILY_IPV6
 };
 
+struct bundle_list;
 struct transport {
 	const struct transport_vtable *vtable;
 
@@ -76,6 +77,18 @@ struct transport {
 	 */
 	unsigned got_remote_refs : 1;
 
+	/**
+	 * Indicates whether we already called get_bundle_uri_list(); set by
+	 * transport.c::transport_get_remote_bundle_uri().
+	 */
+	unsigned got_remote_bundle_uri : 1;
+
+	/*
+	 * The results of "command=bundle-uri", if both sides support
+	 * the "bundle-uri" capability.
+	 */
+	struct bundle_list *bundles;
+
 	/*
 	 * Transports that call take-over destroys the data specific to
 	 * the transport type while doing so, and cannot be reused.
@@ -281,6 +294,12 @@ void transport_ls_refs_options_release(struct transport_ls_refs_options *opts);
 const struct ref *transport_get_remote_refs(struct transport *transport,
 					    struct transport_ls_refs_options *transport_options);
 
+/**
+ * Retrieve bundle URI(s) from a remote. Populates "struct
+ * transport"'s "bundle_uri" and "got_remote_bundle_uri".
+ */
+int transport_get_remote_bundle_uri(struct transport *transport);
+
 /*
  * Fetch the hash algorithm used by a remote.
  *