Advertise h2-16, h2-15, h2-14, and accept any of them.

(Fixing the rollback from earlier - we were passing '1' as the protocol count, not num_alpn_protocols)
	Change on 2014/12/10 by ctiller <ctiller@google.com>
-------------
Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=81783755

2 files changed, 21 insertions, 5 deletions

diff --git a/src/core/transport/chttp2/alpn.c b/src/core/transport/chttp2/alpn.c
index cd9cf67a90..8107406f8b 100644
--- a/src/core/transport/chttp2/alpn.c
+++ b/src/core/transport/chttp2/alpn.c
@@ -32,14 +32,25 @@
  */
 
 #include "src/core/transport/chttp2/alpn.h"
+#include <grpc/support/log.h>
+#include <grpc/support/useful.h>
 
-static const char *const supported_versions[] = {GRPC_CHTTP2_ALPN_VERSION,
-                                                 "h2-15", "h2-14"};
+/* in order of preference */
+static const char *const supported_versions[] = {"h2-16", "h2-15", "h2-14"};
 
 int grpc_chttp2_is_alpn_version_supported(const char *version, size_t size) {
   size_t i;
-  for (i = 0; i < sizeof(supported_versions) / sizeof(const char *); i++) {
+  for (i = 0; i < GPR_ARRAY_SIZE(supported_versions); i++) {
     if (!strncmp(version, supported_versions[i], size)) return 1;
   }
   return 0;
 }
+
+size_t grpc_chttp2_num_alpn_versions() {
+  return GPR_ARRAY_SIZE(supported_versions);
+}
+
+const char *grpc_chttp2_get_alpn_version_index(size_t i) {
+  GPR_ASSERT(i < GPR_ARRAY_SIZE(supported_versions));
+  return supported_versions[i];
+}
diff --git a/src/core/transport/chttp2/alpn.h b/src/core/transport/chttp2/alpn.h
index 1353a18b1b..de4da8fedb 100644
--- a/src/core/transport/chttp2/alpn.h
+++ b/src/core/transport/chttp2/alpn.h
@@ -36,9 +36,14 @@
 
 #include <string.h>
 
-#define GRPC_CHTTP2_ALPN_VERSION "h2-15"
-
 /* Retuns 1 if the version is supported, 0 otherwise. */
 int grpc_chttp2_is_alpn_version_supported(const char *version, size_t size);
 
+/* Returns the number of protocol versions to advertise */
+size_t grpc_chttp2_num_alpn_versions();
+
+/* Returns the protocol version at index i (0 <= i <
+ * grpc_chttp2_num_alpn_versions()) */
+const char *grpc_chttp2_get_alpn_version_index(size_t i);
+
 #endif /* __GRPC_INTERNAL_TRANSPORT_CHTTP2_ALPN_H_ */