degesch: begin work on direct introspection

1 files changed, 176 insertions, 30 deletions

diff --git a/degesch.c b/degesch.c
index bbc9b0f..255bcff 100644
--- a/degesch.c
+++ b/degesch.c
@@ -1241,6 +1241,49 @@ weak_unref (struct weak_ref_link **list, struct weak_ref_link **link)
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
+// Simple introspection framework to simplify exporting stuff to Lua, since
+// there is a lot of it.  While not fully automated, at least we have control
+// over which fields are exported.
+
+enum ispect_type
+{
+	ISPECT_BOOL,
+	ISPECT_INT,
+	ISPECT_UINT,
+	ISPECT_SIZE,
+	ISPECT_STRING,
+#if 0
+	// TODO: also str_map, str_vector
+	ISPECT_REF,                         ///< Weakly referenced
+	ISPECT_LIST,                        ///< Typically copied, depending on type
+#endif
+};
+
+// TODO: once this finalizes, turn instatiations into macros
+struct ispect
+{
+	// TODO:
+	//   - "list" flag?
+	//   - weak_ref/weak_unref methods?
+	struct ispect_field *fields;        ///< Fields
+};
+
+struct ispect_field
+{
+	const char *name;                   ///< Name of the field
+	size_t offset;                      ///< Offset in the structure
+	enum ispect_type type;              ///< Type of the field
+	struct ispect *subtype;             ///< Subtype information
+};
+
+#define ISPECT(object, field, type)                                            \
+	{ #field, offsetof (struct object, field), ISPECT_ ## type, NULL },
+#define ISPECT_(object, field, type, subtype)                                  \
+	{ #field, offsetof (struct object, field), ISPECT_ ## type,                \
+	  &g_ ## subtype ## _type },
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
 struct user_channel
 {
 	LIST_HEADER (struct user_channel)
@@ -1279,6 +1322,18 @@ struct user
 	struct user_channel *channels;      ///< Channels the user is on
 };
 
+static struct ispect_field g_user_ispect_fields[] =
+{
+	ISPECT( user, nickname, STRING )
+	ISPECT( user, away,     BOOL   )
+	{}
+};
+
+static struct ispect g_user_ispect =
+{
+	.fields = g_user_ispect_fields,
+};
+
 static struct user *
 user_new (void)
 {
@@ -1347,6 +1402,20 @@ struct channel
 	bool left_manually;                 ///< Don't rejoin on reconnect
 };
 
+static struct ispect_field g_channel_ispect_fields[] =
+{
+	ISPECT( channel, name,          STRING )
+	ISPECT( channel, topic,         STRING )
+	ISPECT( channel, users_len,     SIZE   )
+	ISPECT( channel, left_manually, BOOL   )
+	{}
+};
+
+static struct ispect g_channel_ispect =
+{
+	.fields = g_channel_ispect_fields,
+};
+
 static struct channel *
 channel_new (void)
 {
@@ -1519,6 +1588,21 @@ struct buffer
 	struct user *user;                  ///< Reference to user
 };
 
+static struct ispect_field g_buffer_ispect_fields[] =
+{
+	ISPECT( buffer, name,                  STRING )
+	ISPECT( buffer, new_messages_count,    UINT   )
+	ISPECT( buffer, new_unimportant_count, UINT   )
+	ISPECT( buffer, highlighted,           BOOL   )
+	ISPECT( buffer, hide_unimportant,      BOOL   )
+	{}
+};
+
+static struct ispect g_buffer_ispect =
+{
+	.fields = g_buffer_ispect_fields,
+};
+
 static struct buffer *
 buffer_new (struct input *input)
 {
@@ -1667,6 +1751,23 @@ struct server
 	unsigned irc_max_modes;             ///< Max parametrized modes per command
 };
 
+static struct ispect_field g_server_ispect_fields[] =
+{
+	ISPECT( server, name,              STRING )
+	ISPECT( server, state,             INT    )
+	ISPECT( server, reconnect_attempt, UINT   )
+	ISPECT( server, manual_disconnect, BOOL   )
+	ISPECT( server, irc_user_host,     STRING )
+	ISPECT( server, autoaway_active,   BOOL   )
+	ISPECT( server, cap_echo_message,  BOOL   )
+	{}
+};
+
+static struct ispect g_server_ispect =
+{
+	.fields = g_server_ispect_fields,
+};
+
 static void on_irc_timeout (void *user_data);
 static void on_irc_ping_timeout (void *user_data);
 static void on_irc_autojoin_timeout (void *user_data);
@@ -8418,6 +8519,10 @@ typedef void (*lua_weak_unref_fn) (void *object, struct weak_ref_link **link);
 struct lua_weak_info
 {
 	const char *name;                   ///< Metatable name
+	struct ispect *ispect;              ///< Introspection data
+
+	// XXX: not sure if these should be _here_ and not in "struct ispect"
+
 	lua_weak_ref_fn ref;                ///< Weak link invalidator
 	lua_weak_unref_fn unref;            ///< Weak link generator
 };
@@ -8425,6 +8530,7 @@ struct lua_weak_info
 struct lua_weak
 {
 	struct lua_plugin *plugin;          ///< The plugin we belong to
+	struct lua_weak_info *info;         ///< Introspection data
 	void *object;                       ///< The object
 	struct weak_ref_link *weak_ref;     ///< A weak reference link
 };
@@ -8455,6 +8561,7 @@ lua_weak_push (struct lua_plugin *plugin, void *object,
 	struct lua_weak *wrapper = lua_newuserdata (L, sizeof *wrapper);
 	luaL_setmetatable (L, info->name);
 	wrapper->plugin = plugin;
+	wrapper->info = info;
 	wrapper->object = object;
 	wrapper->weak_ref = info->ref (object, lua_weak_invalidate, wrapper);
 	lua_cache_store (L, object, -1);
@@ -8486,9 +8593,10 @@ lua_weak_deref (lua_State *L, const struct lua_weak_info *info)
 #define LUA_WEAK_DECLARE(id, metatable_id)                                     \
 	static struct lua_weak_info lua_ ## id ## _info =                          \
 	{                                                                          \
-		.name  = metatable_id,                                                 \
-		.ref   = (lua_weak_ref_fn)   id ## _weak_ref,                          \
-		.unref = (lua_weak_unref_fn) id ## _weak_unref,                        \
+		.name   = metatable_id,                                                \
+		.ispect = &g_ ## id ## _ispect,                                        \
+		.ref    = (lua_weak_ref_fn)   id ## _weak_ref,                         \
+		.unref  = (lua_weak_unref_fn) id ## _weak_unref,                       \
 	};
 
 #define XLUA_USER_METATABLE    "user"     ///< Identifier for Lua metatable
@@ -8510,15 +8618,6 @@ lua_user_gc (lua_State *L)
 }
 
 static int
-lua_user_get_nickname (lua_State *L)
-{
-	struct lua_weak *wrapper = lua_weak_deref (L, &lua_user_info);
-	struct user *user = wrapper->object;
-	lua_pushstring (L, user->nickname);
-	return 1;
-}
-
-static int
 lua_user_get_channels (lua_State *L)
 {
 	struct lua_weak *wrapper = lua_weak_deref (L, &lua_user_info);
@@ -8537,7 +8636,6 @@ lua_user_get_channels (lua_State *L)
 static luaL_Reg lua_user_table[] =
 {
 	{ "__gc",         lua_user_gc           },
-	{ "get_nickname", lua_user_get_nickname },
 	{ "get_channels", lua_user_get_channels },
 	{ NULL,           NULL                  }
 };
@@ -8551,15 +8649,6 @@ lua_channel_gc (lua_State *L)
 }
 
 static int
-lua_channel_get_name (lua_State *L)
-{
-	struct lua_weak *wrapper = lua_weak_deref (L, &lua_channel_info);
-	struct channel *channel = wrapper->object;
-	lua_pushstring (L, channel->name);
-	return 1;
-}
-
-static int
 lua_channel_get_users (lua_State *L)
 {
 	struct lua_weak *wrapper = lua_weak_deref (L, &lua_channel_info);
@@ -8582,7 +8671,6 @@ lua_channel_get_users (lua_State *L)
 static luaL_Reg lua_channel_table[] =
 {
 	{ "__gc",      lua_channel_gc        },
-	{ "get_name",  lua_channel_get_name  },
 	{ "get_users", lua_channel_get_users },
 	{ NULL,        NULL                  }
 };
@@ -8645,7 +8733,6 @@ lua_buffer_execute (lua_State *L)
 
 static luaL_Reg lua_buffer_table[] =
 {
-	// TODO: some useful methods or values
 	{ "__gc",        lua_buffer_gc          },
 	{ "get_user",    lua_buffer_get_user    },
 	{ "get_channel", lua_buffer_get_channel },
@@ -8692,7 +8779,6 @@ lua_server_send (lua_State *L)
 
 static luaL_Reg lua_server_table[] =
 {
-	// TODO: some useful methods or values
 	{ "__gc",       lua_server_gc         },
 	{ "get_user",   lua_server_get_user   },
 	{ "get_buffer", lua_server_get_buffer },
@@ -9701,6 +9787,16 @@ static luaL_Reg lua_plugin_library[] =
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
+static struct lua_ispect_mapping
+{
+	struct ispect *ispect;              ///< Type info
+	struct lua_weak_info *info;         ///< Lua-specific additions
+}
+lua_types[] =
+{
+	{ &g_buffer_ispect, &lua_buffer_info },
+};
+
 static void *
 lua_plugin_alloc (void *ud, void *ptr, size_t o_size, size_t n_size)
 {
@@ -9724,6 +9820,35 @@ lua_plugin_panic (lua_State *L)
 	return 0;
 }
 
+static bool
+lua_plugin_property_get_ispect (lua_State *L, const char *property_name)
+{
+	struct lua_weak_info *info = lua_touserdata (L, lua_upvalueindex (1));
+	if (!info || !info->ispect)
+		return false;
+
+	struct lua_weak *weak = luaL_checkudata (L, 1, info->name);
+	// TODO: I think we can do better than this, maybe binary search at least?
+	struct ispect_field *iter;
+	for (iter = info->ispect->fields; iter->name; iter++)
+		if (!strcmp (property_name, iter->name))
+			break;
+
+	if (iter->name)
+	{
+		void *p = (uint8_t *) weak->object + iter->offset;
+		switch (iter->type)
+		{
+		case ISPECT_BOOL:   lua_pushboolean (L, *(bool     *) p); return true;
+		case ISPECT_INT:    lua_pushinteger (L, *(int      *) p); return true;
+		case ISPECT_UINT:   lua_pushinteger (L, *(unsigned *) p); return true;
+		case ISPECT_SIZE:   lua_pushinteger (L, *(size_t   *) p); return true;
+		case ISPECT_STRING: lua_pushstring  (L, *(char    **) p); return true;
+		}
+	}
+	return false;
+}
+
 static int
 lua_plugin_property_get (lua_State *L)
 {
@@ -9746,6 +9871,10 @@ lua_plugin_property_get (lua_State *L)
 		return 1;
 	}
 
+	// Maybe we can find it via introspection
+	if (lua_plugin_property_get_ispect (L, property_name))
+		return 1;
+
 	// Or we look for a property set by the user (__gc cannot be overriden)
 	if (lua_getuservalue (L, 1) != LUA_TTABLE)
 		lua_pushnil (L);
@@ -9787,7 +9916,24 @@ lua_plugin_create_meta (lua_State *L, const char *name, luaL_Reg *fns)
 	luaL_setfuncs (L, fns, 0);
 
 	// Emulate properties for convenience
-	lua_pushcfunction (L, lua_plugin_property_get);
+	lua_pushlightuserdata (L, NULL);
+	lua_pushcclosure (L, lua_plugin_property_get, 1);
+	lua_setfield (L, -2, "__index");
+	lua_pushcfunction (L, lua_plugin_property_set);
+	lua_setfield (L, -2, "__newindex");
+
+	lua_pop (L, 1);
+}
+
+static void
+lua_plugin_create_weak (lua_State *L, struct lua_weak_info *info, luaL_Reg *fns)
+{
+	luaL_newmetatable (L, info->name);
+	luaL_setfuncs (L, fns, 0);
+
+	// Emulate properties for convenience
+	lua_pushlightuserdata (L, info);
+	lua_pushcclosure (L, lua_plugin_property_get, 1);
 	lua_setfield (L, -2, "__index");
 	lua_pushcfunction (L, lua_plugin_property_set);
 	lua_setfield (L, -2, "__newindex");
@@ -9824,10 +9970,10 @@ lua_plugin_load (struct app_context *ctx, const char *filename,
 
 	// Create metatables for our objects
 	lua_plugin_create_meta (L, XLUA_HOOK_METATABLE,       lua_hook_table);
-	lua_plugin_create_meta (L, XLUA_USER_METATABLE,       lua_user_table);
-	lua_plugin_create_meta (L, XLUA_CHANNEL_METATABLE,    lua_channel_table);
-	lua_plugin_create_meta (L, XLUA_BUFFER_METATABLE,     lua_buffer_table);
-	lua_plugin_create_meta (L, XLUA_SERVER_METATABLE,     lua_server_table);
+	lua_plugin_create_weak (L, &lua_user_info,            lua_user_table);
+	lua_plugin_create_weak (L, &lua_channel_info,         lua_channel_table);
+	lua_plugin_create_weak (L, &lua_buffer_info,          lua_buffer_table);
+	lua_plugin_create_weak (L, &lua_server_info,          lua_server_table);
 	lua_plugin_create_meta (L, XLUA_SCHEMA_METATABLE,     lua_schema_table);
 	lua_plugin_create_meta (L, XLUA_CONNECTION_METATABLE, lua_connection_table);
 	lua_plugin_create_meta (L, XLUA_CONNECTOR_METATABLE,  lua_connector_table);