From 4ece73b1e0d8f75fa63a5b39a91731147870bd0a Mon Sep 17 00:00:00 2001
From: Benoit Germain <bnt period germain arrobase gmail period com>
Date: Fri, 20 Dec 2013 11:46:42 +0100
Subject: new config option demote_full_userdata

use demote_full_userdata to select between light userdata demotion or
raising an error when attempting to transfer a non-deep full userdata
---
 src/lanes.lua | 50 ++++++++++++++++----------------------------------
 src/tools.c   | 25 ++++++++++++++++++++++---
 2 files changed, 38 insertions(+), 37 deletions(-)

diff --git a/src/lanes.lua b/src/lanes.lua
index 6e2a736..4856a2d 100644
--- a/src/lanes.lua
+++ b/src/lanes.lua
@@ -71,52 +71,34 @@ lanes.configure = function( settings_)
 		shutdown_timeout = 0.25,
 		with_timers = true,
 		track_lanes = false,
+		demote_full_userdata = nil,
 		verbose_errors = false,
 		-- LuaJIT provides a thread-unsafe allocator by default, so we need to protect it when used in parallel lanes
 		protect_allocator = (jit and jit.version) and true or false
 	}
+	local boolean_param_checker = function( val_)
+		-- non-'boolean-false' should be 'boolean-true' or nil
+		return val_ and (val_ == true) or true
+	end
 	local param_checkers =
 	{
-		nb_keepers = function( _val)
+		nb_keepers = function( val_)
 			-- nb_keepers should be a number > 0
-			return type( _val) == "number" and _val > 0
-		end,
-		with_timers = function( _val)
-			-- with_timers may be nil or boolean
-			if _val then
-				return type( _val) == "boolean"
-			else
-				return true -- _val is either false or nil
-			end
+			return type( val_) == "number" and val_ > 0
 		end,
-		protect_allocator = function( _val)
-			-- protect_allocator may be nil or boolean
-			if _val then
-				return type( _val) == "boolean"
-			else
-				return true -- _val is either false or nil
-			end
-		end,
-		on_state_create = function( _val)
+		with_timers = boolean_param_checker,
+		protect_allocator = boolean_param_checker,
+		on_state_create = function( val_)
 			-- on_state_create may be nil or a function
-			return _val and type( _val) == "function" or true
+			return val_ and type( val_) == "function" or true
 		end,
-		shutdown_timeout = function( _val)
+		shutdown_timeout = function( val_)
 			-- shutdown_timeout should be a number >= 0
-			return type( _val) == "number" and _val >= 0
-		end,
-		track_lanes = function( _val)
-			-- track_lanes may be nil or boolean
-			return _val and type( _val) == "boolean" or true
+			return type( val_) == "number" and val_ >= 0
 		end,
-		verbose_errors = function( _val)
-			-- verbose_errors may be nil or boolean
-			if _val then
-				return type( _val) == "boolean"
-			else
-				return true -- _val is either false or nil
-			end
-		end
+		track_lanes = boolean_param_checker,
+		demote_full_userdata = boolean_param_checker,
+		verbose_errors = boolean_param_checker
 	}
 
 	local params_checker = function( settings_)
diff --git a/src/tools.c b/src/tools.c
index b5f2f4b..e743393 100644
--- a/src/tools.c
+++ b/src/tools.c
@@ -1886,9 +1886,28 @@ static bool_t inter_copy_one_( lua_State* L2, uint_t L2_cache_i, lua_State* L, u
 		DEBUGSPEW_CODE( fprintf( stderr, INDENT_BEGIN "USERDATA\n" INDENT_END));
 		if( !luaG_copydeep( L, L2, i))
 		{
-			// Cannot copy it full; copy as light userdata
-			//
-			lua_pushlightuserdata( L2, lua_touserdata( L, i));
+			// Not a deep full userdata
+			bool_t demote = FALSE;
+			lua_getfield( L, LUA_REGISTRYINDEX, CONFIG_REGKEY);
+			if( lua_istable( L, -1)) // should not happen, but who knows...
+			{
+				lua_getfield( L, -1, "demote_full_userdata");
+				demote = lua_toboolean( L, -1);
+				lua_pop( L, 2);
+			}
+			else
+			{
+				lua_pop( L, 1);
+			}
+			if( demote) // attempt demotion to light userdata
+			{
+				void* lud = lua_touserdata( L, i);
+				lua_pushlightuserdata( L2, lud);
+			}
+			else // raise an error
+			{
+				(void) luaL_error( L, "can't copy non-deep full userdata across lanes");
+			}
 		}
 		break;
 
-- 
cgit v1.2.3-55-g6feb