From aff1261b08a8e106a0e8ccd7be7499b6bb11a078 Mon Sep 17 00:00:00 2001
From: takase1121 <20792268+takase1121@users.noreply.github.com>
Date: Wed, 1 Dec 2021 20:41:27 +0800
Subject: [PATCH] move NULL check to import side

---
 scripts/generate_header.sh | 10 +++++++++-
 src/api/system.c           |  1 -
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/scripts/generate_header.sh b/scripts/generate_header.sh
index 3613de17..8d5da527 100755
--- a/scripts/generate_header.sh
+++ b/scripts/generate_header.sh
@@ -38,6 +38,11 @@ ptrize() {
   grep '^LUA' | grep -v "$IGNORE_SYM" | sed -e "s/$sym_regex/static\t\2(*\3)\t(\4);/"
 }
 
+# create a stub function that warns user when calling it
+makestub() {
+  grep '^LUA' | grep -v "$IGNORE_SYM" | sed -e "s/$sym_regex/static\t\2\t__lite_xl_fallback_\3\t(\4) { fputs(\"warning: \3 is a stub\", stderr); }/"
+}
+
 import_sym() {
   grep '^LUA' | grep -v "$IGNORE_SYM" | sed -e "s/$sym_regex/\tIMPORT_SYMBOL(\3, \2, \4);/"
 }
@@ -55,6 +60,8 @@ decl() {
   ptrize <<< "$header1"
   # defines
   (grep '^#' | grep -v "$IGNORE_SYM") <<< "$header"
+  # stubs
+  makestub <<< "$header1"
 }
 
 decl_import() {
@@ -93,7 +100,7 @@ generate_header() {
   decl "$LUA_PATH/lauxlib.h"
   echo
 
-  echo "#define IMPORT_SYMBOL(name, ret, ...) name = (ret (*) (__VA_ARGS__)) symbol(#name)"
+  echo "#define IMPORT_SYMBOL(name, ret, ...) name = (name = (ret (*) (__VA_ARGS__)) symbol(#name), name == NULL ? &__lite_xl_fallback_##name : name)"
   echo "static void lite_xl_plugin_init(void *XL) {"
   echo -e "\tvoid* (*symbol)(const char *) = (void* (*) (const char *)) XL;"
 
@@ -134,3 +141,4 @@ main() {
 }
 
 main "$@"
+# create a stub function that warns user when calling it
diff --git a/src/api/system.c b/src/api/system.c
index f42a46d2..70b5b01c 100644
--- a/src/api/system.c
+++ b/src/api/system.c
@@ -699,7 +699,6 @@ static void* api_require(const char* symbol) {
     if (strcmp(nodes[i].symbol, symbol) == 0)
       return nodes[i].address;
   }
-  fprintf(stderr, "WARNING: %s is not available\n", symbol);
   return NULL;
 }