Add a naming system for IDs in dispatch.

src/lib/dispatch/.may_include

@@ -2,6 +2,7 @@ orconfig.h
 
 ext/tor_queue.h
 
+lib/cc/*.h
 lib/container/*.h
 lib/dispatch/*.h
 lib/intmath/*.h

src/lib/dispatch/dispatch_naming.c

+/* Copyright (c) 2001, Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#include "orconfig.h"
+
+#include "lib/cc/compat_compiler.h"
+
+#include "lib/dispatch/dispatch_naming.h"
+#include "lib/dispatch/msgtypes.h"
+
+#include "lib/container/namemap.h"
+#include "lib/container/namemap_st.h"
+
+#include "lib/log/util_bug.h"
+#include "lib/log/log.h"
+
+#include <stdlib.h>
+
+/** Global namemap for message IDs. */
+static namemap_t message_id_map = NAMEMAP_INIT();
+/** Global namemap for subsystem IDs. */
+static namemap_t subsys_id_map = NAMEMAP_INIT();
+/** Global namemap for channel IDs. */
+static namemap_t channel_id_map = NAMEMAP_INIT();
+/** Global namemap for message type IDs. */
+static namemap_t msg_type_id_map = NAMEMAP_INIT();
+
+void
+dispatch_naming_init(void)
+{
+}
+
+/* Helper macro: declare functions to map IDs to and from names for a given
+ * type in a namemap_t.
+ */
+#define DECLARE_ID_MAP_FNS(type)                                        \
+  type##_id_t                                                           \
+  get_##type##_id(const char *name)                                     \
+  {                                                                     \
+    unsigned u = namemap_get_or_create_id(&type##_id_map, name);        \
+    tor_assert(u != NAMEMAP_ERR);                                       \
+    tor_assert(u != ERROR_ID);                                          \
+    return (type##_id_t) u;                                             \
+  }                                                                     \
+  const char *                                                          \
+  get_##type##_id_name(type##_id_t id)                                  \
+  {                                                                     \
+    return namemap_fmt_name(&type##_id_map, id);                        \
+  }                                                                     \
+  size_t                                                                \
+  get_num_##type##_ids(void)                                            \
+  {                                                                     \
+    return namemap_get_size(&type##_id_map);                            \
+  }                                                                     \
+  EAT_SEMICOLON
+
+DECLARE_ID_MAP_FNS(message);
+DECLARE_ID_MAP_FNS(channel);
+DECLARE_ID_MAP_FNS(subsys);
+DECLARE_ID_MAP_FNS(msg_type);

src/lib/dispatch/dispatch_naming.h

+/* Copyright (c) 2001, Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#ifndef TOR_DISPATCH_NAMING_H
+#define TOR_DISPATCH_NAMING_H
+
+#include "lib/dispatch/msgtypes.h"
+#include <stddef.h>
+
+/**
+ * Return an existing channel ID by name, allocating the channel ID if
+ * if necessary.  Returns ERROR_ID if we have run out of
+ * channels
+ */
+channel_id_t get_channel_id(const char *);
+/**
+ * Return the name corresponding to a given channel ID.
+ **/
+const char *get_channel_id_name(channel_id_t);
+/**
+ * Return the total number of _named_ channel IDs.
+ **/
+size_t get_num_channel_ids(void);
+
+/* As above, but for messages. */
+message_id_t get_message_id(const char *);
+const char *get_message_id_name(message_id_t);
+size_t get_num_message_ids(void);
+
+/* As above, but for subsystems */
+subsys_id_t get_subsys_id(const char *);
+const char *get_subsys_id_name(subsys_id_t);
+size_t get_num_subsys_ids(void);
+
+/* As above, but for types. Note that types additionally must be
+ * "defined", if any message is to use them. */
+msg_type_id_t get_msg_type_id(const char *);
+const char *get_msg_type_id_name(msg_type_id_t);
+size_t get_num_msg_type_ids(void);
+
+void dispatch_naming_init(void);
+
+#endif

src/lib/dispatch/include.am

@@ -8,6 +8,7 @@ endif
 src_lib_libtor_dispatch_a_SOURCES =			\
 	src/lib/dispatch/dispatch_cfg.c			\
 	src/lib/dispatch/dispatch_core.c		\
+	src/lib/dispatch/dispatch_naming.c		\
 	src/lib/dispatch/dispatch_new.c
 
 src_lib_libtor_dispatch_testing_a_SOURCES = \
@@ -19,5 +20,6 @@ noinst_HEADERS +=					\
 	src/lib/dispatch/dispatch.h			\
 	src/lib/dispatch/dispatch_cfg.h 		\
 	src/lib/dispatch/dispatch_cfg_st.h 		\
+	src/lib/dispatch/dispatch_naming.h		\
 	src/lib/dispatch/dispatch_st.h			\
 	src/lib/dispatch/msgtypes.h