Make entity on_punch have same signature and behaviour as player on_punch

doc/lua_api.txt

@@ -1392,7 +1392,7 @@ a non-tool item, so that it can do something else than take damage.
 
 On the Lua side, every punch calls:
 
-    entity:on_punch(puncher, time_from_last_punch, tool_capabilities, direction)
+    entity:on_punch(puncher, time_from_last_punch, tool_capabilities, direction, damage)
 
 This should never be called directly, because damage is usually not handled by
 the entity itself.
@@ -1403,6 +1403,9 @@ the entity itself.
 * `tool_capabilities` can be `nil`.
 * `direction` is a unit vector, pointing from the source of the punch to
    the punched object.
+* `damage` damage that will be done to entity
+Return value of this function will determin if damage is done by this function 
+(retval true) or shall be done by engine (retval false)
 
 To punch an entity/object in Lua, call:
 

src/content_sao.cpp

@@ -578,6 +578,10 @@ int LuaEntitySAO::punch(v3f dir,
 			punchitem,
 			time_from_last_punch);
 
+	bool damage_handled = m_env->getScriptIface()->luaentity_Punch(m_id, puncher,
+			time_from_last_punch, toolcap, dir, result.did_punch ? result.damage : 0);
+
+	if (!damage_handled) {
 		if (result.did_punch) {
 			setHP(getHP() - result.damage);
 
@@ -594,12 +598,12 @@ int LuaEntitySAO::punch(v3f dir,
 			ActiveObjectMessage aom(getId(), true, str);
 			m_messages_out.push(aom);
 		}
+	}
 
 	if (getHP() == 0)
 		m_removed = true;
 
-	m_env->getScriptIface()->luaentity_Punch(m_id, puncher,
+
-			time_from_last_punch, toolcap, dir);
 
 	return result.wear;
 }

src/script/cpp_api/s_entity.cpp

@@ -224,10 +224,10 @@ void ScriptApiEntity::luaentity_Step(u16 id, float dtime)
 }
 
 // Calls entity:on_punch(ObjectRef puncher, time_from_last_punch,
-//                       tool_capabilities, direction)
+//                       tool_capabilities, direction, damage)
-void ScriptApiEntity::luaentity_Punch(u16 id,
+bool ScriptApiEntity::luaentity_Punch(u16 id,
 		ServerActiveObject *puncher, float time_from_last_punch,
-		const ToolCapabilities *toolcap, v3f dir)
+		const ToolCapabilities *toolcap, v3f dir, s16 damage)
 {
 	SCRIPTAPI_PRECHECKHEADER
 
@@ -242,8 +242,8 @@ void ScriptApiEntity::luaentity_Punch(u16 id,
 	// Get function
 	lua_getfield(L, -1, "on_punch");
 	if (lua_isnil(L, -1)) {
-		lua_pop(L, 2); // Pop on_punch and entitu
+		lua_pop(L, 2); // Pop on_punch and entity
-		return;
+		return false;
 	}
 	luaL_checktype(L, -1, LUA_TFUNCTION);
 	lua_pushvalue(L, object);  // self
@@ -251,11 +251,14 @@ void ScriptApiEntity::luaentity_Punch(u16 id,
 	lua_pushnumber(L, time_from_last_punch);
 	push_tool_capabilities(L, *toolcap);
 	push_v3f(L, dir);
+	lua_pushnumber(L, damage);
 
 	setOriginFromTable(object);
-	PCALL_RES(lua_pcall(L, 5, 0, error_handler));
+	PCALL_RES(lua_pcall(L, 6, 0, error_handler));
 
+	bool retval = lua_toboolean(L, -1);
 	lua_pop(L, 2); // Pop object and error handler
+	return retval;
 }
 
 // Calls entity:on_rightclick(ObjectRef clicker)

src/script/cpp_api/s_entity.h

@@ -38,9 +38,9 @@ public:
 	void luaentity_GetProperties(u16 id,
 			ObjectProperties *prop);
 	void luaentity_Step(u16 id, float dtime);
-	void luaentity_Punch(u16 id,
+	bool luaentity_Punch(u16 id,
 			ServerActiveObject *puncher, float time_from_last_punch,
-			const ToolCapabilities *toolcap, v3f dir);
+			const ToolCapabilities *toolcap, v3f dir, s16 damage);
 	void luaentity_Rightclick(u16 id,
 			ServerActiveObject *clicker);
 };