bundle-uri: download bundles from an advertised list

The logic in fetch_bundle_uri() is useful for the --bundle-uri option of
'git clone', but is not helpful when the clone operation discovers a
list of URIs from the bundle-uri protocol v2 command. To actually
download and unbundle the advertised bundles, we need a different
mechanism.

Create the new fetch_bundle_list() method which is very similar to
fetch_bundle_uri() except that it relies on download_bundle_list()
instead of fetch_bundle_uri_internal(). The download_bundle_list()
method will recursively call fetch_bundle_uri_internal() if any of the
advertised URIs serve a bundle list instead of a bundle. This will also
follow the bundle.list.mode setting from the input list: "any" will
download only one such URI while "all" will download data from all of
the URIs.

In an identical way to fetch_bundle_uri(), the bundles are unbundled
after all of the bundle lists have been expanded and all necessary URIs.

Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

bundle-uri.c

@@ -577,6 +577,27 @@ cleanup:
 	return result;
 }
 
+int fetch_bundle_list(struct repository *r, struct bundle_list *list)
+{
+	int result;
+	struct bundle_list global_list;
+
+	init_bundle_list(&global_list);
+
+	/* If a bundle is added to this global list, then it is required. */
+	global_list.mode = BUNDLE_MODE_ALL;
+
+	if ((result = download_bundle_list(r, list, &global_list, 0)))
+		goto cleanup;
+
+	result = unbundle_all_bundles(r, &global_list);
+
+cleanup:
+	for_all_bundles_in_list(&global_list, unlink_bundle, NULL);
+	clear_bundle_list(&global_list);
+	return result;
+}
+
 /**
  * API for serve.c.
  */

bundle-uri.h

@@ -107,6 +107,20 @@ int bundle_uri_parse_config_format(const char *uri,
  */
 int fetch_bundle_uri(struct repository *r, const char *uri);
 
+/**
+ * Given a bundle list that was already advertised (likely by the
+ * bundle-uri protocol v2 verb) at the given uri, fetch and unbundle the
+ * bundles according to the bundle strategy of that list.
+ *
+ * It is expected that the given 'list' is initialized, including its
+ * 'baseURI' value.
+ *
+ * Returns non-zero if there was an error trying to download the list
+ * or any of its advertised bundles.
+ */
+int fetch_bundle_list(struct repository *r,
+		      struct bundle_list *list);
+
 /**
  * API for serve.c.
  */