From: Josef 'Jeff' Sipek <jeff.sipek@open-xchange.com>
Date: Thu, 25 Feb 2021 15:22:24 +0000 (-0500)
Subject: lib-lua: Add DLUA_WRAP_C_DATA macro to more easily expose C structures to lua
X-Git-Tag: 2.3.15~172
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=21a2bddaeb9737a91d086c0e24895c70efe19d5c;p=thirdparty%2Fdovecot%2Fcore.git

lib-lua: Add DLUA_WRAP_C_DATA macro to more easily expose C structures to lua
---

diff --git a/src/lib-lua/Makefile.am b/src/lib-lua/Makefile.am
index c2c4e5ac1e..99a64636bc 100644
--- a/src/lib-lua/Makefile.am
+++ b/src/lib-lua/Makefile.am
@@ -19,7 +19,8 @@ libdovecot_lua_la_LDFLAGS = -export-dynamic
 headers = \
 	dlua-compat.h \
 	dlua-script.h \
-	dlua-script-private.h
+	dlua-script-private.h \
+	dlua-wrapper.h
 
 pkginc_libdir=$(pkgincludedir)
 pkginc_lib_HEADERS = $(headers)
diff --git a/src/lib-lua/dlua-wrapper.h b/src/lib-lua/dlua-wrapper.h
new file mode 100644
index 0000000000..a86c6b255b
--- /dev/null
+++ b/src/lib-lua/dlua-wrapper.h
@@ -0,0 +1,111 @@
+/*
+ * Copyright (c) 2020 Josef 'Jeff' Sipek <jeffpc@josefsipek.net>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#ifndef DLUA_WRAPPER_H
+#define DLUA_WRAPPER_H
+
+#define DLUA_WRAP_C_DATA(typename, type, putref, extra_fxns_arg)	\
+struct lua_wrapper_##typename {						\
+	type *ptr;							\
+	bool ro;							\
+};									\
+									\
+static inline type *xlua_##typename##_getptr(lua_State *state, int idx,	\
+					 bool *ro_r)			\
+{									\
+	struct lua_wrapper_##typename *wrapper;				\
+									\
+	wrapper = luaL_checkudata(state, idx, #type);			\
+									\
+	if (ro_r != NULL)						\
+		*ro_r = wrapper->ro;					\
+									\
+	return wrapper->ptr;						\
+}									\
+									\
+static int xlua_wrapper_##typename##_gc(lua_State *state)		\
+{									\
+	putref(xlua_##typename##_getptr(state, -1, NULL));		\
+									\
+	return 0;							\
+}									\
+									\
+static const luaL_Reg provided_##typename##_fxns[] = {			\
+	{ "__gc", xlua_wrapper_##typename##_gc },			\
+	{ NULL, NULL },							\
+};									\
+									\
+/* push [-0,+1,e] */							\
+static void xlua_push##typename(lua_State *state, type *ptr, bool ro)	\
+{									\
+	struct lua_wrapper_##typename *wrapper;				\
+									\
+	if (ptr == NULL) {						\
+		lua_pushnil(state);					\
+		return;							\
+	}								\
+									\
+	wrapper = lua_newuserdata(state, sizeof(struct lua_wrapper_##typename)); \
+	i_assert(wrapper != NULL);					\
+									\
+	wrapper->ptr = (ptr);						\
+	wrapper->ro = ro;						\
+									\
+	/* get the current metatable */					\
+	luaL_getmetatable(state, #type);				\
+	if (lua_type(state, -1) != LUA_TTABLE) {			\
+		/* initialize a new metatable */			\
+		luaL_Reg *extra_fxns = (extra_fxns_arg);		\
+		lua_CFunction index;					\
+									\
+		lua_pop(state, 1);					\
+		luaL_newmetatable(state, #type);			\
+		luaL_setfuncs(state, provided_##typename##_fxns, 0);	\
+									\
+		index = NULL;						\
+		if (extra_fxns != NULL) {				\
+			unsigned i;					\
+									\
+			luaL_setfuncs(state, extra_fxns, 0);		\
+									\
+			for (i = 0; extra_fxns[i].name != NULL; i++) {	\
+				if (strcmp(extra_fxns[i].name,		\
+					   "__index") == 0) {		\
+					index = extra_fxns[i].func;	\
+					break;				\
+				}					\
+			}						\
+		}							\
+									\
+		if (index == NULL) {					\
+			/* set __index == metatable */			\
+			lua_pushliteral(state, "__index");		\
+			lua_pushvalue(state, -2); /* dup the table */	\
+			lua_settable(state, -3);			\
+		}							\
+	}								\
+									\
+	/* set the metatable */						\
+	lua_setmetatable(state, -2);					\
+}
+
+#endif