source/texk/web2c/luatexdir/luasocket/src/except.c

   1 /*=========================================================================*\
   2 * Simple exception support
   3 * LuaSocket toolkit
   4 \*=========================================================================*/
   5 #include <stdio.h>
   6
   7 #include "lua.h"
   8 #include "lauxlib.h"
   9
  10 #include "except.h"
  11
  12 /*=========================================================================*\
  13 * Internal function prototypes.
  14 \*=========================================================================*/
  15 static int global_protect(lua_State *L);
  16 static int global_newtry(lua_State *L);
  17 static int protected_(lua_State *L);
  18 static int finalize(lua_State *L);
  19 static int do_nothing(lua_State *L);
  20
  21 /* except functions */
  22 static luaL_Reg func[] = {
  23     {"newtry",    global_newtry},
  24     {"protect",   global_protect},
  25     {NULL,        NULL}
  26 };
  27
  28 /*-------------------------------------------------------------------------*\
  29 * Try factory
  30 \*-------------------------------------------------------------------------*/
  31 static void wrap(lua_State *L) {
  32     lua_newtable(L);
  33     lua_pushnumber(L, 1);
  34     lua_pushvalue(L, -3);
  35     lua_settable(L, -3);
  36     lua_insert(L, -2);
  37     lua_pop(L, 1);
  38 }
  39
  40 static int finalize(lua_State *L) {
  41     if (!lua_toboolean(L, 1)) {
  42         lua_pushvalue(L, lua_upvalueindex(1));
  43         lua_pcall(L, 0, 0, 0);
  44         lua_settop(L, 2);
  45         wrap(L);
  46         lua_error(L);
  47         return 0;
  48     } else return lua_gettop(L);
  49 }
  50
  51 static int do_nothing(lua_State *L) {
  52     (void) L;
  53     return 0;
  54 }
  55
  56 static int global_newtry(lua_State *L) {
  57     lua_settop(L, 1);
  58     if (lua_isnil(L, 1)) lua_pushcfunction(L, do_nothing);
  59     lua_pushcclosure(L, finalize, 1);
  60     return 1;
  61 }
  62
  63 /*-------------------------------------------------------------------------*\
  64 * Protect factory
  65 \*-------------------------------------------------------------------------*/
  66 static int unwrap(lua_State *L) {
  67     if (lua_istable(L, -1)) {
  68         lua_pushnumber(L, 1);
  69         lua_gettable(L, -2);
  70         lua_pushnil(L);
  71         lua_insert(L, -2);
  72         return 1;
  73     } else return 0;
  74 }
  75
  76 static int protected_(lua_State *L) {
  77     lua_pushvalue(L, lua_upvalueindex(1));
  78     lua_insert(L, 1);
  79     if (lua_pcall(L, lua_gettop(L) - 1, LUA_MULTRET, 0) != 0) {
  80         if (unwrap(L)) return 2;
  81         else lua_error(L);
  82         return 0;
  83     } else return lua_gettop(L);
  84 }
  85
  86 static int global_protect(lua_State *L) {
  87     lua_pushcclosure(L, protected_, 1);
  88     return 1;
  89 }
  90
  91 /*-------------------------------------------------------------------------*\
  92 * Init module
  93 \*-------------------------------------------------------------------------*/
  94 int except_open(lua_State *L) {
  95     luaL_openlib(L, NULL, func, 0);
  96     return 0;
  97 }