1 files changed, 84 insertions, 2 deletions
diff --git a/src/core/ext/filters/client_channel/lb_policy_factory.h b/src/core/ext/filters/client_channel/lb_policy_factory.h
index a165ebafab..a59deadb26 100644
--- a/src/core/ext/filters/client_channel/lb_policy_factory.h
+++ b/src/core/ext/filters/client_channel/lb_policy_factory.h
@@ -21,9 +21,91 @@
 
 #include <grpc/support/port_platform.h>
 
+#include "src/core/lib/iomgr/resolve_address.h"
+
+#include "src/core/ext/filters/client_channel/client_channel_factory.h"
 #include "src/core/ext/filters/client_channel/lb_policy.h"
-#include "src/core/lib/gprpp/abstract.h"
-#include "src/core/lib/gprpp/orphanable.h"
+#include "src/core/lib/uri/uri_parser.h"
+
+//
+// representation of an LB address
+//
+
+// Channel arg key for grpc_lb_addresses.
+#define GRPC_ARG_LB_ADDRESSES "grpc.lb_addresses"
+
+/** A resolved address alongside any LB related information associated with it.
+ * \a user_data, if not NULL, contains opaque data meant to be consumed by the
+ * gRPC LB policy. Note that no all LB policies support \a user_data as input.
+ * Those who don't will simply ignore it and will correspondingly return NULL in
+ * their namesake pick() output argument. */
+// TODO(roth): Once we figure out a better way of handling user_data in
+// LB policies, convert these structs to C++ classes.
+typedef struct grpc_lb_address {
+  grpc_resolved_address address;
+  bool is_balancer;
+  char* balancer_name; /* For secure naming. */
+  void* user_data;
+} grpc_lb_address;
+
+typedef struct grpc_lb_user_data_vtable {
+  void* (*copy)(void*);
+  void (*destroy)(void*);
+  int (*cmp)(void*, void*);
+} grpc_lb_user_data_vtable;
+
+typedef struct grpc_lb_addresses {
+  size_t num_addresses;
+  grpc_lb_address* addresses;
+  const grpc_lb_user_data_vtable* user_data_vtable;
+} grpc_lb_addresses;
+
+/** Returns a grpc_addresses struct with enough space for
+    \a num_addresses addresses.  The \a user_data_vtable argument may be
+    NULL if no user data will be added. */
+grpc_lb_addresses* grpc_lb_addresses_create(
+    size_t num_addresses, const grpc_lb_user_data_vtable* user_data_vtable);
+
+/** Creates a copy of \a addresses. */
+grpc_lb_addresses* grpc_lb_addresses_copy(const grpc_lb_addresses* addresses);
+
+/** Sets the value of the address at index \a index of \a addresses.
+ * \a address is a socket address of length \a address_len. */
+void grpc_lb_addresses_set_address(grpc_lb_addresses* addresses, size_t index,
+                                   const void* address, size_t address_len,
+                                   bool is_balancer, const char* balancer_name,
+                                   void* user_data);
+
+/** Sets the value of the address at index \a index of \a addresses from \a uri.
+ * Returns true upon success, false otherwise. */
+bool grpc_lb_addresses_set_address_from_uri(grpc_lb_addresses* addresses,
+                                            size_t index, const grpc_uri* uri,
+                                            bool is_balancer,
+                                            const char* balancer_name,
+                                            void* user_data);
+
+/** Compares \a addresses1 and \a addresses2. */
+int grpc_lb_addresses_cmp(const grpc_lb_addresses* addresses1,
+                          const grpc_lb_addresses* addresses2);
+
+/** Destroys \a addresses. */
+void grpc_lb_addresses_destroy(grpc_lb_addresses* addresses);
+
+/** Returns a channel arg containing \a addresses. */
+grpc_arg grpc_lb_addresses_create_channel_arg(
+    const grpc_lb_addresses* addresses);
+
+/** Returns the \a grpc_lb_addresses instance in \a channel_args or NULL */
+grpc_lb_addresses* grpc_lb_addresses_find_channel_arg(
+    const grpc_channel_args* channel_args);
+
+// Returns true if addresses contains at least one balancer address.
+bool grpc_lb_addresses_contains_balancer_address(
+    const grpc_lb_addresses& addresses);
+
+//
+// LB policy factory
+//
 
 namespace grpc_core {