From 3c4bf2554bb28fc254f2d3b03dccfecc4b52e26b Mon Sep 17 00:00:00 2001
From: Sveinung Kvilhaugsvik <sveinung84@users.sourceforge.net>
Date: Wed, 3 Feb 2021 09:08:25 +0100
Subject: [PATCH 9/9] Lua script API: add tile extras_owner.

Export a tile's extras owner to Lua.

v2: change API to tile/extra pair as suggested by Marko Lindqvist

See osdn #41445
---
 common/scriptcore/api_game_methods.c | 36 ++++++++++++++++++++++++++++
 common/scriptcore/api_game_methods.h |  2 ++
 common/scriptcore/tolua_game.pkg     |  2 ++
 3 files changed, 40 insertions(+)

diff --git a/common/scriptcore/api_game_methods.c b/common/scriptcore/api_game_methods.c
index c16cc93682..a13cfdea66 100644
--- a/common/scriptcore/api_game_methods.c
+++ b/common/scriptcore/api_game_methods.c
@@ -894,6 +894,42 @@ bool api_methods_tile_has_road(lua_State *L, Tile *ptile, const char *name)
   }
 }
 
+/**********************************************************************//**
+  Return the extra owner for the specified extra on ptile or NULL if the
+  extra isn't there.
+  If no name is specified the owner of the first owned extra at the tile
+  is returned.
+**************************************************************************/
+Player *api_methods_tile_extra_owner(lua_State *L,
+                                     Tile *ptile, const char *extra_name)
+{
+  LUASCRIPT_CHECK_STATE(L, NULL);
+  LUASCRIPT_CHECK_SELF(L, ptile, NULL);
+
+  if (extra_name) {
+    struct extra_type *pextra;
+
+    pextra = extra_type_by_rule_name(extra_name);
+    LUASCRIPT_CHECK_ARG(L, pextra != NULL, 3, "unknown extra type", NULL);
+
+    if (tile_has_extra(ptile, pextra)) {
+      /* All extras have the same owner. */
+      return extra_owner(ptile);
+    } else {
+      /* The extra isn't there. */
+      return NULL;
+    }
+  } else {
+    extra_type_iterate(pextra) {
+      if (tile_has_extra(ptile, pextra)) {
+        /* All extras have the same owner. */
+        return extra_owner(ptile);
+      }
+    } extra_type_iterate_end;
+    return NULL;
+  }
+}
+
 /*************************************************************************//**
   Is tile occupied by enemies
 *****************************************************************************/
diff --git a/common/scriptcore/api_game_methods.h b/common/scriptcore/api_game_methods.h
index 3d19dd489d..9a1e01ba18 100644
--- a/common/scriptcore/api_game_methods.h
+++ b/common/scriptcore/api_game_methods.h
@@ -136,6 +136,8 @@ bool api_methods_tile_city_exists_within_max_city_map(lua_State *L,
 bool api_methods_tile_has_extra(lua_State *L, Tile *ptile, const char *name);
 bool api_methods_tile_has_base(lua_State *L, Tile *ptile, const char *name);
 bool api_methods_tile_has_road(lua_State *L, Tile *ptile, const char *name);
+Player *api_methods_tile_extra_owner(lua_State *L,
+                                     Tile *ptile, const char *extra_name);
 bool api_methods_enemy_tile(lua_State *L, Tile *ptile, Player *against);
 int api_methods_tile_num_units(lua_State *L, Tile *ptile);
 int api_methods_tile_sq_distance(lua_State *L, Tile *ptile1, Tile *ptile2);
diff --git a/common/scriptcore/tolua_game.pkg b/common/scriptcore/tolua_game.pkg
index 6330507f30..5cdedd79b7 100644
--- a/common/scriptcore/tolua_game.pkg
+++ b/common/scriptcore/tolua_game.pkg
@@ -296,6 +296,8 @@ module Tile {
     @ has_base(lua_State *L, Tile *self, const char *name);
   bool api_methods_tile_has_road
     @ has_road(lua_State *L, Tile *self, const char *name);
+  Player *api_methods_tile_extra_owner
+    @ extra_owner(lua_State *L, Tile *self, const char *extra_name);
   bool api_methods_enemy_tile
     @ is_enemy(lua_State *L, Tile *self, Player *against);
   int api_methods_tile_num_units
-- 
2.20.1