From edd3b36a9fd6785ddc3507bc14077c2f13a03172 Mon Sep 17 00:00:00 2001
From: Enno Rehling <enno.rehling@gmail.com>
Date: Sun, 30 Apr 2017 18:18:47 +0200
Subject: [PATCH] add a callbacks module. make last-chance spell function in
 lua for spells with none.

---
 src/bindings.c            | 14 ++++++++++++++
 src/bindings.h            |  1 +
 src/helpers.c             | 14 --------------
 src/helpers.h             |  5 ++---
 src/kernel/CMakeLists.txt |  2 ++
 src/kernel/callbacks.c    |  4 ++++
 src/kernel/callbacks.h    | 35 +++++++++++++++++++++++++++++++++++
 src/magic.c               |  6 +++++-
 8 files changed, 63 insertions(+), 18 deletions(-)
 create mode 100644 src/kernel/callbacks.c
 create mode 100644 src/kernel/callbacks.h

diff --git a/src/bindings.c b/src/bindings.c
index 1d6270b35..9ea548465 100755
--- a/src/bindings.c
+++ b/src/bindings.c
@@ -92,6 +92,20 @@ TOLUA_PKG(locale);
 TOLUA_PKG(log);
 TOLUA_PKG(game);
 
+int tolua_toid(lua_State * L, int idx, int def)
+{
+    int no = 0;
+    int type = lua_type(L, idx);
+    if (type == LUA_TNUMBER) {
+        no = (int)tolua_tonumber(L, idx, def);
+    }
+    else {
+        const char *str = tolua_tostring(L, idx, NULL);
+        no = str ? atoi36(str) : def;
+    }
+    return no;
+}
+
 int log_lua_error(lua_State * L)
 {
     const char *error = lua_tostring(L, -1);
diff --git a/src/bindings.h b/src/bindings.h
index 354bb199a..2275236cb 100755
--- a/src/bindings.h
+++ b/src/bindings.h
@@ -18,6 +18,7 @@ extern "C" {
     struct _dictionary_;
     struct selist;
 
+    int tolua_toid(struct lua_State * L, int idx, int def);
     int tolua_sqlite_open(struct lua_State *L);
     int tolua_bindings_open(struct lua_State *L, const struct _dictionary_ *d);
     int tolua_itemlist_next(struct lua_State *L);
diff --git a/src/helpers.c b/src/helpers.c
index 59695e9b4..924082bcd 100644
--- a/src/helpers.c
+++ b/src/helpers.c
@@ -455,20 +455,6 @@ use_item_lua(unit *u, const item_type *itype, int amount, struct order *ord)
     return result;
 }
 
-int tolua_toid(lua_State * L, int idx, int def)
-{
-    int no = 0;
-    int type = lua_type(L, idx);
-    if (type == LUA_TNUMBER) {
-        no = (int)tolua_tonumber(L, idx, def);
-    }
-    else {
-        const char *str = tolua_tostring(L, idx, NULL);
-        no = str ? atoi36(str) : def;
-    }
-    return no;
-}
-
 void register_tolua_helpers(void)
 {
     at_register(&at_direction);
diff --git a/src/helpers.h b/src/helpers.h
index d77765187..5187f7bcf 100644
--- a/src/helpers.h
+++ b/src/helpers.h
@@ -14,9 +14,8 @@ without prior permission by the authors of Eressea.
 extern "C" {
 #endif
 
-  struct lua_State;
-  void register_tolua_helpers(void);
-  int tolua_toid(struct lua_State *L, int idx, int def);
+    struct lua_State;
+    void register_tolua_helpers(void);
 
 #ifdef __cplusplus
 }
diff --git a/src/kernel/CMakeLists.txt b/src/kernel/CMakeLists.txt
index b8423ae03..e572d0763 100644
--- a/src/kernel/CMakeLists.txt
+++ b/src/kernel/CMakeLists.txt
@@ -6,6 +6,7 @@ alliance.test.c
 ally.test.c
 build.test.c
 building.test.c
+# callbacks.test.c
 command.test.c
 config.test.c
 # connection.test.c
@@ -38,6 +39,7 @@ alliance.c
 ally.c
 build.c
 building.c
+callbacks.c
 command.c
 config.c
 connection.c
diff --git a/src/kernel/callbacks.c b/src/kernel/callbacks.c
new file mode 100644
index 000000000..d8070bd04
--- /dev/null
+++ b/src/kernel/callbacks.c
@@ -0,0 +1,4 @@
+#include <platform.h>
+#include "callbacks.h"
+
+struct callbacks callbacks;
diff --git a/src/kernel/callbacks.h b/src/kernel/callbacks.h
new file mode 100644
index 000000000..99db5e390
--- /dev/null
+++ b/src/kernel/callbacks.h
@@ -0,0 +1,35 @@
+/*
+Copyright (c) 1998-2015, Enno Rehling <enno@eressea.de>
+Katja Zedel <katze@felidae.kn-bremen.de
+Christian Schlittchen <corwin@amber.kn-bremen.de>
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+**/
+
+#ifndef H_KRNL_CALLBACKS_H
+#define H_KRNL_CALLBACKS_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+    struct castorder;
+
+    extern struct callbacks {
+        int (*cast_spell)(struct castorder *co);
+    } callbacks;
+
+#ifdef __cplusplus
+}
+#endif
+#endif /* H_KRNL_CALLBACKS_H */
diff --git a/src/magic.c b/src/magic.c
index 602207c02..8db533923 100644
--- a/src/magic.c
+++ b/src/magic.c
@@ -27,6 +27,7 @@ OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 
 #include <kernel/ally.h>
 #include <kernel/building.h>
+#include <kernel/callbacks.h>
 #include <kernel/curse.h>
 #include <kernel/faction.h>
 #include <kernel/item.h>
@@ -3006,7 +3007,10 @@ spell *unit_getspell(struct unit *u, const char *name, const struct locale * lan
 int cast_spell(struct castorder *co)
 {
     const spell *sp = co->sp;
-    return sp->cast_fun(co);
+    if (sp->cast_fun) {
+        return sp->cast_fun(co);
+    }
+    return callbacks.cast_spell(co);
 }
 
 static critbit_tree cb_spellbooks;