degesch: refactor Lua weak objects

1 files changed, 111 insertions, 222 deletions

diff --git a/degesch.c b/degesch.c
index f1eceb8..61355ef 100644
--- a/degesch.c
+++ b/degesch.c
@@ -8322,113 +8322,126 @@ lua_plugin_parse (lua_State *L)
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-#define XLUA_USER_METATABLE "user"      ///< Identifier for the Lua metatable
+// Lua code can use weakly referenced wrappers for internal objects.
 
-struct lua_user
+typedef struct weak_ref_link *
+	(*lua_weak_ref_fn) (void *object, destroy_cb_fn cb, void *user_data);
+typedef void (*lua_weak_unref_fn) (void *object, struct weak_ref_link **link);
+
+struct lua_weak_info
+{
+	const char *name;                   ///< Metatable name
+	lua_weak_ref_fn ref;                ///< Weak link invalidator
+	lua_weak_unref_fn unref;            ///< Weak link generator
+};
+
+struct lua_weak
 {
 	struct lua_plugin *plugin;          ///< The plugin we belong to
-	struct user *user;                  ///< The user
+	void *object;                       ///< The object
 	struct weak_ref_link *weak_ref;     ///< A weak reference link
 };
 
 static void
-lua_user_invalidate (void *object, void *user_data)
+lua_weak_invalidate (void *object, void *user_data)
 {
-	struct lua_user *wrapper = user_data;
-	wrapper->user = NULL;
+	struct lua_weak *wrapper = user_data;
+	wrapper->object = NULL;
 	wrapper->weak_ref = NULL;
 	// This can in theory call the GC, order isn't arbitrary here
 	lua_cache_invalidate (wrapper->plugin->L, object);
 }
 
 static void
-lua_plugin_push_user (struct lua_plugin *plugin, struct user *user)
+lua_weak_push (struct lua_plugin *plugin, void *object,
+	struct lua_weak_info *info)
 {
 	lua_State *L = plugin->L;
-	if (lua_cache_get (L, user))
+	if (!object)
+	{
+		lua_pushnil (L);
+		return;
+	}
+	if (lua_cache_get (L, object))
 		return;
 
-	struct lua_user *wrapper = lua_newuserdata (L, sizeof *wrapper);
-	luaL_setmetatable (L, XLUA_USER_METATABLE);
+	struct lua_weak *wrapper = lua_newuserdata (L, sizeof *wrapper);
+	luaL_setmetatable (L, info->name);
 	wrapper->plugin = plugin;
-	wrapper->user = user;
-	wrapper->weak_ref = user_weak_ref (user, lua_user_invalidate, wrapper);
-	lua_cache_store (L, user, -1);
+	wrapper->object = object;
+	wrapper->weak_ref = info->ref (object, lua_weak_invalidate, wrapper);
+	lua_cache_store (L, object, -1);
 }
 
-// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-
-/// Identifier for the Lua metatable
-#define XLUA_CHANNEL_METATABLE "channel"
-
-struct lua_channel
+static int
+lua_weak_gc (lua_State *L, const struct lua_weak_info *info)
 {
-	struct lua_plugin *plugin;          ///< The plugin we belong to
-	struct channel *channel;            ///< The channel
-	struct weak_ref_link *weak_ref;     ///< A weak reference link
-};
+	struct lua_weak *wrapper = luaL_checkudata (L, 1, info->name);
+	if (wrapper->object)
+	{
+		lua_cache_invalidate (L, wrapper->object);
+		info->unref (wrapper->object, &wrapper->weak_ref);
+		wrapper->object = NULL;
+	}
+	return 0;
+}
 
-static void
-lua_channel_invalidate (void *object, void *user_data)
+static struct lua_weak *
+lua_weak_deref (lua_State *L, const struct lua_weak_info *info)
 {
-	struct lua_channel *wrapper = user_data;
-	wrapper->channel = NULL;
-	wrapper->weak_ref = NULL;
-	// This can in theory call the GC, order isn't arbitrary here
-	lua_cache_invalidate (wrapper->plugin->L, object);
+	struct lua_weak *weak = luaL_checkudata (L, 1, info->name);
+	luaL_argcheck (L, weak->object, 1, "dead reference used");
+	return weak;
 }
 
-static void
-lua_plugin_push_channel (struct lua_plugin *plugin, struct channel *channel)
-{
-	lua_State *L = plugin->L;
-	if (lua_cache_get (L, channel))
-		return;
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-	struct lua_channel *wrapper = lua_newuserdata (L, sizeof *wrapper);
-	luaL_setmetatable (L, XLUA_CHANNEL_METATABLE);
-	wrapper->plugin = plugin;
-	wrapper->channel = channel;
-	wrapper->weak_ref = channel_weak_ref
-		(channel, lua_channel_invalidate, wrapper);
-	lua_cache_store (L, channel, -1);
-}
+#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,                        \
+	};
+
+#define XLUA_USER_METATABLE    "user"     ///< Identifier for Lua metatable
+#define XLUA_CHANNEL_METATABLE "channel"  ///< Identifier for Lua metatable
+#define XLUA_BUFFER_METATABLE  "buffer"   ///< Identifier for Lua metatable
+#define XLUA_SERVER_METATABLE  "server"   ///< Identifier for Lua metatable
+
+LUA_WEAK_DECLARE (user,    XLUA_USER_METATABLE)
+LUA_WEAK_DECLARE (channel, XLUA_CHANNEL_METATABLE)
+LUA_WEAK_DECLARE (buffer,  XLUA_BUFFER_METATABLE)
+LUA_WEAK_DECLARE (server,  XLUA_SERVER_METATABLE)
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
 static int
 lua_user_gc (lua_State *L)
 {
-	struct lua_user *wrapper = luaL_checkudata (L, 1, XLUA_USER_METATABLE);
-	if (wrapper->user)
-	{
-		lua_cache_invalidate (L, wrapper->user);
-		user_weak_unref (wrapper->user, &wrapper->weak_ref);
-		wrapper->user = NULL;
-	}
-	return 0;
+	return lua_weak_gc (L, &lua_user_info);
 }
 
 static int
 lua_user_get_nickname (lua_State *L)
 {
-	struct lua_user *wrapper = luaL_checkudata (L, 1, XLUA_USER_METATABLE);
-	luaL_argcheck (L, wrapper->user, 1, "dead reference used");
-	lua_pushstring (L, wrapper->user->nickname);
+	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_user *wrapper = luaL_checkudata (L, 1, XLUA_USER_METATABLE);
-	luaL_argcheck (L, wrapper->user, 1, "dead reference used");
+	struct lua_weak *wrapper = lua_weak_deref (L, &lua_user_info);
+	struct user *user = wrapper->object;
 
 	int i = 1;
 	lua_newtable (L);
-	LIST_FOR_EACH (struct user_channel, iter, wrapper->user->channels)
+	LIST_FOR_EACH (struct user_channel, iter, user->channels)
 	{
-		lua_plugin_push_channel (wrapper->plugin, iter->channel);
+		lua_weak_push (wrapper->plugin, iter->channel, &lua_channel_info);
 		lua_rawseti (L, -2, i++);
 	}
 	return 1;
@@ -8447,40 +8460,30 @@ static luaL_Reg lua_user_table[] =
 static int
 lua_channel_gc (lua_State *L)
 {
-	struct lua_channel *wrapper =
-		luaL_checkudata (L, 1, XLUA_CHANNEL_METATABLE);
-	if (wrapper->channel)
-	{
-		lua_cache_invalidate (L, wrapper->channel);
-		channel_weak_unref (wrapper->channel, &wrapper->weak_ref);
-		wrapper->channel = NULL;
-	}
-	return 0;
+	return lua_weak_gc (L, &lua_channel_info);
 }
 
 static int
 lua_channel_get_name (lua_State *L)
 {
-	struct lua_channel *wrapper =
-		luaL_checkudata (L, 1, XLUA_CHANNEL_METATABLE);
-	luaL_argcheck (L, wrapper->channel, 1, "dead reference used");
-	lua_pushstring (L, wrapper->channel->name);
+	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_channel *wrapper =
-		luaL_checkudata (L, 1, XLUA_CHANNEL_METATABLE);
-	luaL_argcheck (L, wrapper->channel, 1, "dead reference used");
+	struct lua_weak *wrapper = lua_weak_deref (L, &lua_channel_info);
+	struct channel *channel = wrapper->object;
 
 	int i = 1;
 	lua_newtable (L);
-	LIST_FOR_EACH (struct channel_user, iter, wrapper->channel->users)
+	LIST_FOR_EACH (struct channel_user, iter, channel->users)
 	{
 		lua_createtable (L, 0, 2);
-		lua_plugin_push_user (wrapper->plugin, iter->user);
+		lua_weak_push (wrapper->plugin, iter->user, &lua_user_info);
 		lua_setfield (L, -2, "user");
 		lua_plugin_kv (L, "prefixes", iter->prefixes.str);
 
@@ -8499,140 +8502,45 @@ static luaL_Reg lua_channel_table[] =
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-#define XLUA_BUFFER_METATABLE "buffer"  ///< Identifier for the Lua metatable
-
-struct lua_buffer
-{
-	struct lua_plugin *plugin;          ///< The plugin we belong to
-	struct buffer *buffer;              ///< The buffer
-	struct weak_ref_link *weak_ref;     ///< A weak reference link
-};
-
-static void
-lua_buffer_invalidate (void *object, void *user_data)
-{
-	struct lua_buffer *wrapper = user_data;
-	wrapper->buffer = NULL;
-	wrapper->weak_ref = NULL;
-	// This can in theory call the GC, order isn't arbitrary here
-	lua_cache_invalidate (wrapper->plugin->L, object);
-}
-
-static void
-lua_plugin_push_buffer (struct lua_plugin *plugin, struct buffer *buffer)
-{
-	lua_State *L = plugin->L;
-	if (lua_cache_get (L, buffer))
-		return;
-
-	struct lua_buffer *wrapper = lua_newuserdata (L, sizeof *wrapper);
-	luaL_setmetatable (L, XLUA_BUFFER_METATABLE);
-	wrapper->plugin = plugin;
-	wrapper->buffer = buffer;
-	wrapper->weak_ref = buffer_weak_ref
-		(buffer, lua_buffer_invalidate, wrapper);
-	lua_cache_store (L, buffer, -1);
-}
-
-// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-
-#define XLUA_SERVER_METATABLE "server"  ///< Identifier for the Lua metatable
-
-struct lua_server
-{
-	struct lua_plugin *plugin;          ///< The plugin we belong to
-	struct server *server;              ///< The server
-	struct weak_ref_link *weak_ref;     ///< A weak reference link
-};
-
-static void
-lua_server_invalidate (void *object, void *user_data)
-{
-	struct lua_server *wrapper = user_data;
-	wrapper->server = NULL;
-	wrapper->weak_ref = NULL;
-	// This can in theory call the GC, order isn't arbitrary here
-	lua_cache_invalidate (wrapper->plugin->L, object);
-}
-
-static void
-lua_plugin_push_server (struct lua_plugin *plugin, struct server *server)
-{
-	lua_State *L = plugin->L;
-	if (lua_cache_get (L, server))
-		return;
-
-	struct lua_server *wrapper = lua_newuserdata (L, sizeof *wrapper);
-	luaL_setmetatable (L, XLUA_SERVER_METATABLE);
-	wrapper->plugin = plugin;
-	wrapper->server = server;
-	wrapper->weak_ref = server_weak_ref
-		(server, lua_server_invalidate, wrapper);
-	lua_cache_store (L, server, -1);
-}
-
-// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-
 static int
 lua_buffer_gc (lua_State *L)
 {
-	struct lua_buffer *wrapper = luaL_checkudata (L, 1, XLUA_BUFFER_METATABLE);
-	if (wrapper->buffer)
-	{
-		lua_cache_invalidate (L, wrapper->buffer);
-		buffer_weak_unref (wrapper->buffer, &wrapper->weak_ref);
-		wrapper->buffer = NULL;
-	}
-	return 0;
+	return lua_weak_gc (L, &lua_buffer_info);
 }
 
 static int
 lua_buffer_get_user (lua_State *L)
 {
-	struct lua_buffer *wrapper = luaL_checkudata (L, 1, XLUA_BUFFER_METATABLE);
-	luaL_argcheck (L, wrapper->buffer, 1, "dead reference used");
-
-	if (wrapper->buffer->user)
-		lua_plugin_push_user (wrapper->plugin, wrapper->buffer->user);
-	else
-		lua_pushnil (L);
+	struct lua_weak *wrapper = lua_weak_deref (L, &lua_buffer_info);
+	struct buffer *buffer = wrapper->object;
+	lua_weak_push (wrapper->plugin, buffer->user, &lua_user_info);
 	return 1;
 }
 
 static int
 lua_buffer_get_channel (lua_State *L)
 {
-	struct lua_buffer *wrapper = luaL_checkudata (L, 1, XLUA_BUFFER_METATABLE);
-	luaL_argcheck (L, wrapper->buffer, 1, "dead reference used");
-
-	if (wrapper->buffer->channel)
-		lua_plugin_push_channel (wrapper->plugin, wrapper->buffer->channel);
-	else
-		lua_pushnil (L);
+	struct lua_weak *wrapper = lua_weak_deref (L, &lua_buffer_info);
+	struct buffer *buffer = wrapper->object;
+	lua_weak_push (wrapper->plugin, buffer->channel, &lua_channel_info);
 	return 1;
 }
 
 static int
 lua_buffer_get_server (lua_State *L)
 {
-	struct lua_buffer *wrapper = luaL_checkudata (L, 1, XLUA_BUFFER_METATABLE);
-	luaL_argcheck (L, wrapper->buffer, 1, "dead reference used");
-
-	if (wrapper->buffer->server)
-		lua_plugin_push_server (wrapper->plugin, wrapper->buffer->server);
-	else
-		lua_pushnil (L);
+	struct lua_weak *wrapper = lua_weak_deref (L, &lua_buffer_info);
+	struct buffer *buffer = wrapper->object;
+	lua_weak_push (wrapper->plugin, buffer->server, &lua_server_info);
 	return 1;
 }
 
 static int
 lua_buffer_log (lua_State *L)
 {
-	struct lua_buffer *wrapper = luaL_checkudata (L, 1, XLUA_BUFFER_METATABLE);
-	luaL_argcheck (L, wrapper->buffer, 1, "dead reference used");
+	struct lua_weak *wrapper = lua_weak_deref (L, &lua_buffer_info);
+	struct buffer *buffer = wrapper->object;
 	const char *message = lua_plugin_check_utf8 (L, 2);
-
-	struct buffer *buffer = wrapper->buffer;
 	log_full (wrapper->plugin->ctx, buffer->server, buffer,
 		BUFFER_LINE_STATUS, "#s", message);
 	return 0;
@@ -8641,11 +8549,9 @@ lua_buffer_log (lua_State *L)
 static int
 lua_buffer_execute (lua_State *L)
 {
-	struct lua_buffer *wrapper = luaL_checkudata (L, 1, XLUA_BUFFER_METATABLE);
-	luaL_argcheck (L, wrapper->buffer, 1, "dead reference used");
+	struct lua_weak *wrapper = lua_weak_deref (L, &lua_buffer_info);
+	struct buffer *buffer = wrapper->object;
 	const char *line = lua_plugin_check_utf8 (L, 2);
-
-	struct buffer *buffer = wrapper->buffer;
 	process_input_utf8 (wrapper->plugin->ctx, buffer, line, 0);
 	return 0;
 }
@@ -8667,50 +8573,33 @@ static luaL_Reg lua_buffer_table[] =
 static int
 lua_server_gc (lua_State *L)
 {
-	struct lua_server *wrapper = luaL_checkudata (L, 1, XLUA_SERVER_METATABLE);
-	if (wrapper->server)
-	{
-		lua_cache_invalidate (L, wrapper->server);
-		server_weak_unref (wrapper->server, &wrapper->weak_ref);
-		wrapper->server = NULL;
-	}
-	return 0;
+	return lua_weak_gc (L, &lua_server_info);
 }
 
 static int
 lua_server_get_user (lua_State *L)
 {
-	struct lua_server *wrapper = luaL_checkudata (L, 1, XLUA_SERVER_METATABLE);
-	luaL_argcheck (L, wrapper->server, 1, "dead reference used");
-
-	if (wrapper->server->irc_user)
-		lua_plugin_push_user (wrapper->plugin, wrapper->server->irc_user);
-	else
-		lua_pushnil (L);
+	struct lua_weak *wrapper = lua_weak_deref (L, &lua_server_info);
+	struct server *server = wrapper->object;
+	lua_weak_push (wrapper->plugin, server->irc_user, &lua_user_info);
 	return 1;
 }
 
 static int
 lua_server_get_buffer (lua_State *L)
 {
-	struct lua_server *wrapper = luaL_checkudata (L, 1, XLUA_SERVER_METATABLE);
-	luaL_argcheck (L, wrapper->server, 1, "dead reference used");
-
-	if (wrapper->server->buffer)
-		lua_plugin_push_buffer (wrapper->plugin, wrapper->server->buffer);
-	else
-		lua_pushnil (L);
+	struct lua_weak *wrapper = lua_weak_deref (L, &lua_server_info);
+	struct server *server = wrapper->object;
+	lua_weak_push (wrapper->plugin, server->buffer, &lua_buffer_info);
 	return 1;
 }
 
 static int
 lua_server_send (lua_State *L)
 {
-	struct lua_server *wrapper = luaL_checkudata (L, 1, XLUA_SERVER_METATABLE);
-	luaL_argcheck (L, wrapper->server, 1, "dead reference used");
-	const char *line = luaL_checkstring (L, 2);
-
-	irc_send (wrapper->server, "%s", line);
+	struct lua_weak *wrapper = lua_weak_deref (L, &lua_server_info);
+	struct server *server = wrapper->object;
+	irc_send (server, "%s", luaL_checkstring (L, 2));
 	return 0;
 }
 
@@ -8807,9 +8696,9 @@ lua_input_hook_filter (struct input_hook *self, struct buffer *buffer,
 	lua_State *L = plugin->L;
 
 	lua_rawgeti (L, LUA_REGISTRYINDEX, hook->ref_callback);
-	lua_rawgetp (L, LUA_REGISTRYINDEX, hook);  // 1: hook
-	lua_plugin_push_buffer (plugin, buffer);   // 2: buffer
-	lua_pushstring (L, input);                 // 3: input
+	lua_rawgetp (L, LUA_REGISTRYINDEX, hook);          // 1: hook
+	lua_weak_push (plugin, buffer, &lua_buffer_info);  // 2: buffer
+	lua_pushstring (L, input);                         // 3: input
 
 	struct error *e = NULL;
 	if (lua_plugin_call (plugin, 3, 1, &e))
@@ -8838,9 +8727,9 @@ lua_irc_hook_filter (struct irc_hook *self, struct server *s, char *message)
 	lua_State *L = plugin->L;
 
 	lua_rawgeti (L, LUA_REGISTRYINDEX, hook->ref_callback);
-	lua_rawgetp (L, LUA_REGISTRYINDEX, hook);  // 1: hook
-	lua_plugin_push_server (plugin, s);        // 2: server
-	lua_pushstring (L, message);               // 3: message
+	lua_rawgetp (L, LUA_REGISTRYINDEX, hook);     // 1: hook
+	lua_weak_push (plugin, s, &lua_server_info);  // 2: server
+	lua_pushstring (L, message);                  // 3: message
 
 	struct error *e = NULL;
 	if (lua_plugin_call (plugin, 3, 1, &e))
@@ -8927,7 +8816,7 @@ lua_completion_hook_complete (struct completion_hook *self,
 	lua_rawgetp (L, LUA_REGISTRYINDEX, hook);  // 1: hook
 	lua_plugin_push_completion (L, data);      // 2: data
 
-	lua_plugin_push_buffer (plugin, plugin->ctx->current_buffer);
+	lua_weak_push (plugin, plugin->ctx->current_buffer, &lua_buffer_info);
 	lua_setfield (L, -2, "buffer");
 
 	lua_pushstring (L, word);                  // 3: word