From: Josef 'Jeff' Sipek <jeff.sipek@open-xchange.com>
Date: Thu, 4 Mar 2021 21:21:07 +0000 (-0500)
Subject: lib-lua: Implement a Lua 5.1 & 5.2 compatibility wrapper for lua_isinteger
X-Git-Tag: 2.3.15~294
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=32e963965c6ba68a141ec5bd68f6cd3c14f0736a;p=thirdparty%2Fdovecot%2Fcore.git

lib-lua: Implement a Lua 5.1 & 5.2 compatibility wrapper for lua_isinteger
---

diff --git a/src/lib-lua/dlua-compat.c b/src/lib-lua/dlua-compat.c
index f057b09c31..d50d2d53f9 100644
--- a/src/lib-lua/dlua-compat.c
+++ b/src/lib-lua/dlua-compat.c
@@ -25,6 +25,27 @@ void luaL_setfuncs (lua_State *L, const luaL_Reg *l, int nup) {
 }
 #endif
 
+#ifndef HAVE_LUA_ISINTEGER
+#  if LUA_VERSION_NUM >= 503
+#    error "Lua 5.3+ should have lua_isinteger()"
+#  endif
+/*
+ * Lua 5.3 added lua_isinteger() which tells us whether or not the input is
+ * an integer.  In Lua 5.1 and 5.2, we have to emulate it.
+ */
+int lua_isinteger(lua_State *L, int idx)
+{
+	int isnum;
+
+	if (lua_type(L, idx) != LUA_TNUMBER)
+		return 0;
+
+	(void) lua_tointegerx(L, idx, &isnum);
+
+	return isnum;
+}
+#endif
+
 #ifndef HAVE_LUA_TOINTEGERX
 #  if LUA_VERSION_NUM >= 502
 #    error "Lua 5.2+ should have lua_tointegerx()"
diff --git a/src/lib-lua/dlua-compat.h b/src/lib-lua/dlua-compat.h
index d35f474597..f1e564d5d0 100644
--- a/src/lib-lua/dlua-compat.h
+++ b/src/lib-lua/dlua-compat.h
@@ -5,6 +5,18 @@
  * In general, make whatever Lua version we have behave more like Lua 5.3.
  */
 
+#ifndef HAVE_LUA_ISINTEGER
+/*
+ * Lua 5.3 can actually keep track of intergers vs. numbers.  As a
+ * consequence, lua_isinteger() tells us if the internal representation of
+ * the number is an integer (vs. a number).  In previous versions, there was
+ * no way to check for this and our compatibility wrapper is not quite
+ * capable of matching the 5.3 behavior exactly.  Therefore, it returns 1
+ * when the number is representable as an integer instead.
+ */
+int lua_isinteger(lua_State *L, int idx);
+#endif
+
 #ifndef HAVE_LUA_TOINTEGERX
 /*
  * Lua 5.2 and 5.3 both have lua_tointegerx(), but their behavior is subtly
diff --git a/src/lib-lua/test-lua.c b/src/lib-lua/test-lua.c
index 607f275d93..5e7e8e5346 100644
--- a/src/lib-lua/test-lua.c
+++ b/src/lib-lua/test-lua.c
@@ -66,6 +66,7 @@ static void test_lua(void)
 
 /* check lua_tointegerx against top-of-stack item */
 static void check_tointegerx_compat(lua_State *L, int expected_isnum,
+				    int expected_isint,
 				    lua_Integer expected_value)
 {
 	lua_Integer value;
@@ -77,10 +78,12 @@ static void check_tointegerx_compat(lua_State *L, int expected_isnum,
 	if (isnum == 1)
 		test_assert(value == expected_value);
 
+	test_assert(lua_isinteger(L, -1) == expected_isint);
+
 	lua_pop(L, 1);
 }
 
-static void test_compat_tointegerx(void)
+static void test_compat_tointegerx_and_isinteger(void)
 {
 	static const struct {
 		const char *input;
@@ -155,25 +158,35 @@ static void test_compat_tointegerx(void)
 	const char *error;
 	size_t i;
 
-	test_begin("lua compat tostringx");
+	test_begin("lua compat tostringx/isinteger");
 
 	test_assert(dlua_script_create_string("", &script, NULL, &error) == 0);
 
 	for (i = 0; i < N_ELEMENTS(str_tests); i++) {
 		lua_pushstring(script->L, str_tests[i].input);
-		check_tointegerx_compat(script->L, str_tests[i].isnum,
+		check_tointegerx_compat(script->L, str_tests[i].isnum, 0,
 					str_tests[i].output);
 	}
 
 	for (i = 0; i < N_ELEMENTS(num_tests); i++) {
+		int isint;
+
+		/* See lua_isinteger() comment in dlua-compat.h */
+#if LUA_VERSION_NUM == 503
+		isint = 0;
+#else
+		isint = num_tests[i].isnum;
+#endif
+
 		lua_pushnumber(script->L, num_tests[i].input);
 		check_tointegerx_compat(script->L, num_tests[i].isnum,
+					isint,
 					num_tests[i].output);
 	}
 
 	for (i = 0; i < N_ELEMENTS(int_tests); i++) {
 		lua_pushinteger(script->L, int_tests[i].input);
-		check_tointegerx_compat(script->L, 1,
+		check_tointegerx_compat(script->L, 1, 1,
 					int_tests[i].output);
 	}
 
@@ -185,7 +198,7 @@ static void test_compat_tointegerx(void)
 int main(void) {
 	void (*tests[])(void) = {
 		test_lua,
-		test_compat_tointegerx,
+		test_compat_tointegerx_and_isinteger,
 		NULL
 	};