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/*=========================================================================*\
* Simple exception support
* LuaSocket toolkit
\*=========================================================================*/
#include <stdio.h>
#include "lua.h"
#include "lauxlib.h"
#include "compat.h"
#include "except.h"
#if LUA_VERSION_NUM < 502
#define lua_pcallk(L, na, nr, err, ctx, cont) \
(((void)ctx),((void)cont),lua_pcall(L, na, nr, err))
#endif
#if LUA_VERSION_NUM < 503
typedef int lua_KContext;
#endif
/*=========================================================================*\
* Internal function prototypes.
\*=========================================================================*/
static int global_protect(lua_State *L);
static int global_newtry(lua_State *L);
static int protected_(lua_State *L);
static int finalize(lua_State *L);
static int do_nothing(lua_State *L);
/* except functions */
static luaL_Reg func[] = {
{"newtry", global_newtry},
{"protect", global_protect},
{NULL, NULL}
};
/*-------------------------------------------------------------------------*\
* Try factory
\*-------------------------------------------------------------------------*/
static void wrap(lua_State *L) {
lua_createtable(L, 1, 0);
lua_pushvalue(L, -2);
lua_rawseti(L, -2, 1);
lua_pushvalue(L, lua_upvalueindex(1));
lua_setmetatable(L, -2);
}
static int finalize(lua_State *L) {
if (!lua_toboolean(L, 1)) {
lua_pushvalue(L, lua_upvalueindex(2));
lua_call(L, 0, 0);
lua_settop(L, 2);
wrap(L);
lua_error(L);
return 0;
} else return lua_gettop(L);
}
static int do_nothing(lua_State *L) {
(void) L;
return 0;
}
static int global_newtry(lua_State *L) {
lua_settop(L, 1);
if (lua_isnil(L, 1)) lua_pushcfunction(L, do_nothing);
lua_pushvalue(L, lua_upvalueindex(1));
lua_insert(L, -2);
lua_pushcclosure(L, finalize, 2);
return 1;
}
/*-------------------------------------------------------------------------*\
* Protect factory
\*-------------------------------------------------------------------------*/
static int unwrap(lua_State *L) {
if (lua_istable(L, -1) && lua_getmetatable(L, -1)) {
int r = lua_rawequal(L, -1, lua_upvalueindex(1));
lua_pop(L, 1);
if (r) {
lua_pushnil(L);
lua_rawgeti(L, -2, 1);
return 1;
}
}
return 0;
}
static int protected_finish(lua_State *L, int status, lua_KContext ctx) {
(void)ctx;
if (status != 0 && status != LUA_YIELD) {
if (unwrap(L)) return 2;
else return lua_error(L);
} else return lua_gettop(L);
}
#if LUA_VERSION_NUM == 502
static int protected_cont(lua_State *L) {
int ctx = 0;
int status = lua_getctx(L, &ctx);
return protected_finish(L, status, ctx);
}
#else
#define protected_cont protected_finish
#endif
static int protected_(lua_State *L) {
int status;
lua_pushvalue(L, lua_upvalueindex(2));
lua_insert(L, 1);
status = lua_pcallk(L, lua_gettop(L) - 1, LUA_MULTRET, 0, 0, protected_cont);
return protected_finish(L, status, 0);
}
static int global_protect(lua_State *L) {
lua_settop(L, 1);
lua_pushvalue(L, lua_upvalueindex(1));
lua_insert(L, 1);
lua_pushcclosure(L, protected_, 2);
return 1;
}
/*-------------------------------------------------------------------------*\
* Init module
\*-------------------------------------------------------------------------*/
int except_open(lua_State *L) {
lua_newtable(L); /* metatable for wrapped exceptions */
lua_pushboolean(L, 0);
lua_setfield(L, -2, "__metatable");
luaL_setfuncs(L, func, 1);
return 0;
}
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