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1 /*
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2 ** $Id: ldo.c,v 2.38.1.3 2008/01/18 22:31:22 roberto Exp $
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3 ** Stack and Call structure of Lua
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4 ** See Copyright Notice in lua.h
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5 */
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6
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7
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8 #include <setjmp.h>
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9 #include <stdlib.h>
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10 #include <string.h>
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11
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12 #define ldo_c
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13 #define LUA_CORE
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14
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15 #include "lua.h"
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16
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17 #include "ldebug.h"
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18 #include "ldo.h"
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19 #include "lfunc.h"
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20 #include "lgc.h"
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21 #include "lmem.h"
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22 #include "lobject.h"
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23 #include "lopcodes.h"
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24 #include "lparser.h"
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25 #include "lstate.h"
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26 #include "lstring.h"
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27 #include "ltable.h"
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28 #include "ltm.h"
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29 #include "lundump.h"
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30 #include "lvm.h"
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31 #include "lzio.h"
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32
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33
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34
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35
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36 /*
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37 ** {======================================================
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38 ** Error-recovery functions
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39 ** =======================================================
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40 */
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41
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42
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43 /* chain list of long jump buffers */
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44 struct lua_longjmp {
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45 struct lua_longjmp *previous;
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46 luai_jmpbuf b;
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47 volatile int status; /* error code */
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48 };
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49
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50
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51 void luaD_seterrorobj (lua_State *L, int errcode, StkId oldtop) {
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52 switch (errcode) {
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53 case LUA_ERRMEM: {
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54 setsvalue2s(L, oldtop, luaS_newliteral(L, MEMERRMSG));
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55 break;
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56 }
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57 case LUA_ERRERR: {
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58 setsvalue2s(L, oldtop, luaS_newliteral(L, "error in error handling"));
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59 break;
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60 }
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61 case LUA_ERRSYNTAX:
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62 case LUA_ERRRUN: {
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63 setobjs2s(L, oldtop, L->top - 1); /* error message on current top */
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64 break;
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65 }
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66 }
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67 L->top = oldtop + 1;
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68 }
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69
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70
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71 static void restore_stack_limit (lua_State *L) {
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72 lua_assert(L->stack_last - L->stack == L->stacksize - EXTRA_STACK - 1);
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73 if (L->size_ci > LUAI_MAXCALLS) { /* there was an overflow? */
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74 int inuse = cast_int(L->ci - L->base_ci);
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75 if (inuse + 1 < LUAI_MAXCALLS) /* can `undo' overflow? */
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76 luaD_reallocCI(L, LUAI_MAXCALLS);
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77 }
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78 }
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79
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80
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81 static void resetstack (lua_State *L, int status) {
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82 L->ci = L->base_ci;
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83 L->base = L->ci->base;
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84 luaF_close(L, L->base); /* close eventual pending closures */
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85 luaD_seterrorobj(L, status, L->base);
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86 L->nCcalls = L->baseCcalls;
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87 L->allowhook = 1;
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88 restore_stack_limit(L);
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89 L->errfunc = 0;
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90 L->errorJmp = NULL;
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91 }
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92
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93
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94 void luaD_throw (lua_State *L, int errcode) {
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95 if (L->errorJmp) {
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96 L->errorJmp->status = errcode;
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97 LUAI_THROW(L, L->errorJmp);
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98 }
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99 else {
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100 L->status = cast_byte(errcode);
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101 if (G(L)->panic) {
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102 resetstack(L, errcode);
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103 lua_unlock(L);
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104 G(L)->panic(L);
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105 }
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106 exit(EXIT_FAILURE);
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107 }
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108 }
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109
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110
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111 int luaD_rawrunprotected (lua_State *L, Pfunc f, void *ud) {
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112 struct lua_longjmp lj;
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113 lj.status = 0;
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114 lj.previous = L->errorJmp; /* chain new error handler */
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115 L->errorJmp = &lj;
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116 LUAI_TRY(L, &lj,
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117 (*f)(L, ud);
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118 );
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119 L->errorJmp = lj.previous; /* restore old error handler */
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120 return lj.status;
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121 }
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122
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123 /* }====================================================== */
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124
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125
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126 static void correctstack (lua_State *L, TValue *oldstack) {
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127 CallInfo *ci;
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128 GCObject *up;
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129 L->top = (L->top - oldstack) + L->stack;
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130 for (up = L->openupval; up != NULL; up = up->gch.next)
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131 gco2uv(up)->v = (gco2uv(up)->v - oldstack) + L->stack;
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132 for (ci = L->base_ci; ci <= L->ci; ci++) {
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133 ci->top = (ci->top - oldstack) + L->stack;
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134 ci->base = (ci->base - oldstack) + L->stack;
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135 ci->func = (ci->func - oldstack) + L->stack;
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136 }
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137 L->base = (L->base - oldstack) + L->stack;
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138 }
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139
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140
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141 void luaD_reallocstack (lua_State *L, int newsize) {
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142 TValue *oldstack = L->stack;
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143 int realsize = newsize + 1 + EXTRA_STACK;
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144 lua_assert(L->stack_last - L->stack == L->stacksize - EXTRA_STACK - 1);
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145 luaM_reallocvector(L, L->stack, L->stacksize, realsize, TValue);
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146 L->stacksize = realsize;
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147 L->stack_last = L->stack+newsize;
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148 correctstack(L, oldstack);
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149 }
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150
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151
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152 void luaD_reallocCI (lua_State *L, int newsize) {
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153 CallInfo *oldci = L->base_ci;
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154 luaM_reallocvector(L, L->base_ci, L->size_ci, newsize, CallInfo);
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155 L->size_ci = newsize;
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156 L->ci = (L->ci - oldci) + L->base_ci;
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157 L->end_ci = L->base_ci + L->size_ci - 1;
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158 }
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159
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160
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161 void luaD_growstack (lua_State *L, int n) {
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162 if (n <= L->stacksize) /* double size is enough? */
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163 luaD_reallocstack(L, 2*L->stacksize);
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164 else
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165 luaD_reallocstack(L, L->stacksize + n);
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166 }
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167
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168
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169 static CallInfo *growCI (lua_State *L) {
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170 if (L->size_ci > LUAI_MAXCALLS) /* overflow while handling overflow? */
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171 luaD_throw(L, LUA_ERRERR);
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172 else {
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173 luaD_reallocCI(L, 2*L->size_ci);
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174 if (L->size_ci > LUAI_MAXCALLS)
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175 luaG_runerror(L, "stack overflow");
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176 }
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177 return ++L->ci;
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178 }
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179
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180
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181 void luaD_callhook (lua_State *L, int event, int line) {
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182 lua_Hook hook = L->hook;
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183 if (hook && L->allowhook) {
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184 ptrdiff_t top = savestack(L, L->top);
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185 ptrdiff_t ci_top = savestack(L, L->ci->top);
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186 lua_Debug ar;
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187 ar.event = event;
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188 ar.currentline = line;
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189 if (event == LUA_HOOKTAILRET)
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190 ar.i_ci = 0; /* tail call; no debug information about it */
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191 else
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192 ar.i_ci = cast_int(L->ci - L->base_ci);
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193 luaD_checkstack(L, LUA_MINSTACK); /* ensure minimum stack size */
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194 L->ci->top = L->top + LUA_MINSTACK;
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195 lua_assert(L->ci->top <= L->stack_last);
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196 L->allowhook = 0; /* cannot call hooks inside a hook */
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197 lua_unlock(L);
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198 (*hook)(L, &ar);
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199 lua_lock(L);
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200 lua_assert(!L->allowhook);
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201 L->allowhook = 1;
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202 L->ci->top = restorestack(L, ci_top);
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203 L->top = restorestack(L, top);
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204 }
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205 }
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206
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207
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208 static StkId adjust_varargs (lua_State *L, Proto *p, int actual) {
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209 int i;
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210 int nfixargs = p->numparams;
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211 Table *htab = NULL;
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212 StkId base, fixed;
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213 for (; actual < nfixargs; ++actual)
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214 setnilvalue(L->top++);
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215 #if defined(LUA_COMPAT_VARARG)
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216 if (p->is_vararg & VARARG_NEEDSARG) { /* compat. with old-style vararg? */
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217 int nvar = actual - nfixargs; /* number of extra arguments */
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218 lua_assert(p->is_vararg & VARARG_HASARG);
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219 luaC_checkGC(L);
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220 htab = luaH_new(L, nvar, 1); /* create `arg' table */
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221 for (i=0; i<nvar; i++) /* put extra arguments into `arg' table */
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222 setobj2n(L, luaH_setnum(L, htab, i+1), L->top - nvar + i);
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223 /* store counter in field `n' */
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224 setnvalue(luaH_setstr(L, htab, luaS_newliteral(L, "n")), cast_num(nvar));
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225 }
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226 #endif
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227 /* move fixed parameters to final position */
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228 fixed = L->top - actual; /* first fixed argument */
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229 base = L->top; /* final position of first argument */
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230 for (i=0; i<nfixargs; i++) {
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231 setobjs2s(L, L->top++, fixed+i);
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232 setnilvalue(fixed+i);
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233 }
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234 /* add `arg' parameter */
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235 if (htab) {
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236 sethvalue(L, L->top++, htab);
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237 lua_assert(iswhite(obj2gco(htab)));
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238 }
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239 return base;
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240 }
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241
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242
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243 static StkId tryfuncTM (lua_State *L, StkId func) {
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244 const TValue *tm = luaT_gettmbyobj(L, func, TM_CALL);
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245 StkId p;
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246 ptrdiff_t funcr = savestack(L, func);
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247 if (!ttisfunction(tm))
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248 luaG_typeerror(L, func, "call");
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249 /* Open a hole inside the stack at `func' */
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250 for (p = L->top; p > func; p--) setobjs2s(L, p, p-1);
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251 incr_top(L);
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252 func = restorestack(L, funcr); /* previous call may change stack */
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253 setobj2s(L, func, tm); /* tag method is the new function to be called */
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254 return func;
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255 }
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256
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257
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258
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259 #define inc_ci(L) \
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260 ((L->ci == L->end_ci) ? growCI(L) : \
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261 (condhardstacktests(luaD_reallocCI(L, L->size_ci)), ++L->ci))
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262
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263
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264 int luaD_precall (lua_State *L, StkId func, int nresults) {
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265 LClosure *cl;
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266 ptrdiff_t funcr;
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267 if (!ttisfunction(func)) /* `func' is not a function? */
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268 func = tryfuncTM(L, func); /* check the `function' tag method */
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269 funcr = savestack(L, func);
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270 cl = &clvalue(func)->l;
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271 L->ci->savedpc = L->savedpc;
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272 if (!cl->isC) { /* Lua function? prepare its call */
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273 CallInfo *ci;
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274 StkId st, base;
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275 Proto *p = cl->p;
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276 luaD_checkstack(L, p->maxstacksize);
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277 func = restorestack(L, funcr);
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278 if (!p->is_vararg) { /* no varargs? */
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279 base = func + 1;
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280 if (L->top > base + p->numparams)
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281 L->top = base + p->numparams;
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282 }
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283 else { /* vararg function */
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284 int nargs = cast_int(L->top - func) - 1;
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285 base = adjust_varargs(L, p, nargs);
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286 func = restorestack(L, funcr); /* previous call may change the stack */
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287 }
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288 ci = inc_ci(L); /* now `enter' new function */
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289 ci->func = func;
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290 L->base = ci->base = base;
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291 ci->top = L->base + p->maxstacksize;
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292 lua_assert(ci->top <= L->stack_last);
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293 L->savedpc = p->code; /* starting point */
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294 ci->tailcalls = 0;
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295 ci->nresults = nresults;
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296 for (st = L->top; st < ci->top; st++)
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297 setnilvalue(st);
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298 L->top = ci->top;
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299 if (L->hookmask & LUA_MASKCALL) {
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300 L->savedpc++; /* hooks assume 'pc' is already incremented */
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301 luaD_callhook(L, LUA_HOOKCALL, -1);
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302 L->savedpc--; /* correct 'pc' */
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303 }
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304 return PCRLUA;
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rlm@1
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305 }
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306 else { /* if is a C function, call it */
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307 CallInfo *ci;
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308 int n;
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309 luaD_checkstack(L, LUA_MINSTACK); /* ensure minimum stack size */
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310 ci = inc_ci(L); /* now `enter' new function */
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311 ci->func = restorestack(L, funcr);
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312 L->base = ci->base = ci->func + 1;
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313 ci->top = L->top + LUA_MINSTACK;
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314 lua_assert(ci->top <= L->stack_last);
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315 ci->nresults = nresults;
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rlm@1
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316 if (L->hookmask & LUA_MASKCALL)
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317 luaD_callhook(L, LUA_HOOKCALL, -1);
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318 lua_unlock(L);
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319 n = (*curr_func(L)->c.f)(L); /* do the actual call */
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320 lua_lock(L);
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321 if (n < 0) /* yielding? */
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322 return PCRYIELD;
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323 else {
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324 luaD_poscall(L, L->top - n);
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rlm@1
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325 return PCRC;
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rlm@1
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326 }
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rlm@1
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327 }
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rlm@1
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328 }
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329
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330
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rlm@1
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331 static StkId callrethooks (lua_State *L, StkId firstResult) {
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332 ptrdiff_t fr = savestack(L, firstResult); /* next call may change stack */
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333 luaD_callhook(L, LUA_HOOKRET, -1);
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rlm@1
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334 if (f_isLua(L->ci)) { /* Lua function? */
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rlm@1
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335 while ((L->hookmask & LUA_MASKRET) && L->ci->tailcalls--) /* tail calls */
|
rlm@1
|
336 luaD_callhook(L, LUA_HOOKTAILRET, -1);
|
rlm@1
|
337 }
|
rlm@1
|
338 return restorestack(L, fr);
|
rlm@1
|
339 }
|
rlm@1
|
340
|
rlm@1
|
341
|
rlm@1
|
342 int luaD_poscall (lua_State *L, StkId firstResult) {
|
rlm@1
|
343 StkId res;
|
rlm@1
|
344 int wanted, i;
|
rlm@1
|
345 CallInfo *ci;
|
rlm@1
|
346 if (L->hookmask & LUA_MASKRET)
|
rlm@1
|
347 firstResult = callrethooks(L, firstResult);
|
rlm@1
|
348 ci = L->ci--;
|
rlm@1
|
349 res = ci->func; /* res == final position of 1st result */
|
rlm@1
|
350 wanted = ci->nresults;
|
rlm@1
|
351 L->base = (ci - 1)->base; /* restore base */
|
rlm@1
|
352 L->savedpc = (ci - 1)->savedpc; /* restore savedpc */
|
rlm@1
|
353 /* move results to correct place */
|
rlm@1
|
354 for (i = wanted; i != 0 && firstResult < L->top; i--)
|
rlm@1
|
355 setobjs2s(L, res++, firstResult++);
|
rlm@1
|
356 while (i-- > 0)
|
rlm@1
|
357 setnilvalue(res++);
|
rlm@1
|
358 L->top = res;
|
rlm@1
|
359 return (wanted - LUA_MULTRET); /* 0 iff wanted == LUA_MULTRET */
|
rlm@1
|
360 }
|
rlm@1
|
361
|
rlm@1
|
362
|
rlm@1
|
363 /*
|
rlm@1
|
364 ** Call a function (C or Lua). The function to be called is at *func.
|
rlm@1
|
365 ** The arguments are on the stack, right after the function.
|
rlm@1
|
366 ** When returns, all the results are on the stack, starting at the original
|
rlm@1
|
367 ** function position.
|
rlm@1
|
368 */
|
rlm@1
|
369 void luaD_call (lua_State *L, StkId func, int nResults) {
|
rlm@1
|
370 if (++L->nCcalls >= LUAI_MAXCCALLS) {
|
rlm@1
|
371 if (L->nCcalls == LUAI_MAXCCALLS)
|
rlm@1
|
372 luaG_runerror(L, "C stack overflow");
|
rlm@1
|
373 else if (L->nCcalls >= (LUAI_MAXCCALLS + (LUAI_MAXCCALLS>>3)))
|
rlm@1
|
374 luaD_throw(L, LUA_ERRERR); /* error while handing stack error */
|
rlm@1
|
375 }
|
rlm@1
|
376 if (luaD_precall(L, func, nResults) == PCRLUA) /* is a Lua function? */
|
rlm@1
|
377 luaV_execute(L, 1); /* call it */
|
rlm@1
|
378 L->nCcalls--;
|
rlm@1
|
379 luaC_checkGC(L);
|
rlm@1
|
380 }
|
rlm@1
|
381
|
rlm@1
|
382
|
rlm@1
|
383 static void resume (lua_State *L, void *ud) {
|
rlm@1
|
384 StkId firstArg = cast(StkId, ud);
|
rlm@1
|
385 CallInfo *ci = L->ci;
|
rlm@1
|
386 if (L->status == 0) { /* start coroutine? */
|
rlm@1
|
387 lua_assert(ci == L->base_ci && firstArg > L->base);
|
rlm@1
|
388 if (luaD_precall(L, firstArg - 1, LUA_MULTRET) != PCRLUA)
|
rlm@1
|
389 return;
|
rlm@1
|
390 }
|
rlm@1
|
391 else { /* resuming from previous yield */
|
rlm@1
|
392 lua_assert(L->status == LUA_YIELD);
|
rlm@1
|
393 L->status = 0;
|
rlm@1
|
394 if (!f_isLua(ci)) { /* `common' yield? */
|
rlm@1
|
395 /* finish interrupted execution of `OP_CALL' */
|
rlm@1
|
396 lua_assert(GET_OPCODE(*((ci-1)->savedpc - 1)) == OP_CALL ||
|
rlm@1
|
397 GET_OPCODE(*((ci-1)->savedpc - 1)) == OP_TAILCALL);
|
rlm@1
|
398 if (luaD_poscall(L, firstArg)) /* complete it... */
|
rlm@1
|
399 L->top = L->ci->top; /* and correct top if not multiple results */
|
rlm@1
|
400 }
|
rlm@1
|
401 else /* yielded inside a hook: just continue its execution */
|
rlm@1
|
402 L->base = L->ci->base;
|
rlm@1
|
403 }
|
rlm@1
|
404 luaV_execute(L, cast_int(L->ci - L->base_ci));
|
rlm@1
|
405 }
|
rlm@1
|
406
|
rlm@1
|
407
|
rlm@1
|
408 static int resume_error (lua_State *L, const char *msg) {
|
rlm@1
|
409 L->top = L->ci->base;
|
rlm@1
|
410 setsvalue2s(L, L->top, luaS_new(L, msg));
|
rlm@1
|
411 incr_top(L);
|
rlm@1
|
412 lua_unlock(L);
|
rlm@1
|
413 return LUA_ERRRUN;
|
rlm@1
|
414 }
|
rlm@1
|
415
|
rlm@1
|
416
|
rlm@1
|
417 LUA_API int lua_resume (lua_State *L, int nargs) {
|
rlm@1
|
418 int status;
|
rlm@1
|
419 lua_lock(L);
|
rlm@1
|
420 if (L->status != LUA_YIELD && (L->status != 0 || L->ci != L->base_ci))
|
rlm@1
|
421 return resume_error(L, "cannot resume non-suspended coroutine");
|
rlm@1
|
422 if (L->nCcalls >= LUAI_MAXCCALLS)
|
rlm@1
|
423 return resume_error(L, "C stack overflow");
|
rlm@1
|
424 luai_userstateresume(L, nargs);
|
rlm@1
|
425 lua_assert(L->errfunc == 0);
|
rlm@1
|
426 L->baseCcalls = ++L->nCcalls;
|
rlm@1
|
427 status = luaD_rawrunprotected(L, resume, L->top - nargs);
|
rlm@1
|
428 if (status != 0) { /* error? */
|
rlm@1
|
429 L->status = cast_byte(status); /* mark thread as `dead' */
|
rlm@1
|
430 luaD_seterrorobj(L, status, L->top);
|
rlm@1
|
431 L->ci->top = L->top;
|
rlm@1
|
432 }
|
rlm@1
|
433 else {
|
rlm@1
|
434 lua_assert(L->nCcalls == L->baseCcalls);
|
rlm@1
|
435 status = L->status;
|
rlm@1
|
436 }
|
rlm@1
|
437 --L->nCcalls;
|
rlm@1
|
438 lua_unlock(L);
|
rlm@1
|
439 return status;
|
rlm@1
|
440 }
|
rlm@1
|
441
|
rlm@1
|
442
|
rlm@1
|
443 LUA_API int lua_yield (lua_State *L, int nresults) {
|
rlm@1
|
444 luai_userstateyield(L, nresults);
|
rlm@1
|
445 lua_lock(L);
|
rlm@1
|
446 if (L->nCcalls > L->baseCcalls)
|
rlm@1
|
447 luaG_runerror(L, "attempt to yield across metamethod/C-call boundary");
|
rlm@1
|
448 L->base = L->top - nresults; /* protect stack slots below */
|
rlm@1
|
449 L->status = LUA_YIELD;
|
rlm@1
|
450 lua_unlock(L);
|
rlm@1
|
451 return -1;
|
rlm@1
|
452 }
|
rlm@1
|
453
|
rlm@1
|
454
|
rlm@1
|
455 int luaD_pcall (lua_State *L, Pfunc func, void *u,
|
rlm@1
|
456 ptrdiff_t old_top, ptrdiff_t ef) {
|
rlm@1
|
457 int status;
|
rlm@1
|
458 unsigned short oldnCcalls = L->nCcalls;
|
rlm@1
|
459 ptrdiff_t old_ci = saveci(L, L->ci);
|
rlm@1
|
460 lu_byte old_allowhooks = L->allowhook;
|
rlm@1
|
461 ptrdiff_t old_errfunc = L->errfunc;
|
rlm@1
|
462 L->errfunc = ef;
|
rlm@1
|
463 status = luaD_rawrunprotected(L, func, u);
|
rlm@1
|
464 if (status != 0) { /* an error occurred? */
|
rlm@1
|
465 StkId oldtop = restorestack(L, old_top);
|
rlm@1
|
466 luaF_close(L, oldtop); /* close eventual pending closures */
|
rlm@1
|
467 luaD_seterrorobj(L, status, oldtop);
|
rlm@1
|
468 L->nCcalls = oldnCcalls;
|
rlm@1
|
469 L->ci = restoreci(L, old_ci);
|
rlm@1
|
470 L->base = L->ci->base;
|
rlm@1
|
471 L->savedpc = L->ci->savedpc;
|
rlm@1
|
472 L->allowhook = old_allowhooks;
|
rlm@1
|
473 restore_stack_limit(L);
|
rlm@1
|
474 }
|
rlm@1
|
475 L->errfunc = old_errfunc;
|
rlm@1
|
476 return status;
|
rlm@1
|
477 }
|
rlm@1
|
478
|
rlm@1
|
479
|
rlm@1
|
480
|
rlm@1
|
481 /*
|
rlm@1
|
482 ** Execute a protected parser.
|
rlm@1
|
483 */
|
rlm@1
|
484 struct SParser { /* data to `f_parser' */
|
rlm@1
|
485 ZIO *z;
|
rlm@1
|
486 Mbuffer buff; /* buffer to be used by the scanner */
|
rlm@1
|
487 const char *name;
|
rlm@1
|
488 };
|
rlm@1
|
489
|
rlm@1
|
490 static void f_parser (lua_State *L, void *ud) {
|
rlm@1
|
491 int i;
|
rlm@1
|
492 Proto *tf;
|
rlm@1
|
493 Closure *cl;
|
rlm@1
|
494 struct SParser *p = cast(struct SParser *, ud);
|
rlm@1
|
495 int c = luaZ_lookahead(p->z);
|
rlm@1
|
496 luaC_checkGC(L);
|
rlm@1
|
497 tf = ((c == LUA_SIGNATURE[0]) ? luaU_undump : luaY_parser)(L, p->z,
|
rlm@1
|
498 &p->buff, p->name);
|
rlm@1
|
499 cl = luaF_newLclosure(L, tf->nups, hvalue(gt(L)));
|
rlm@1
|
500 cl->l.p = tf;
|
rlm@1
|
501 for (i = 0; i < tf->nups; i++) /* initialize eventual upvalues */
|
rlm@1
|
502 cl->l.upvals[i] = luaF_newupval(L);
|
rlm@1
|
503 setclvalue(L, L->top, cl);
|
rlm@1
|
504 incr_top(L);
|
rlm@1
|
505 }
|
rlm@1
|
506
|
rlm@1
|
507
|
rlm@1
|
508 int luaD_protectedparser (lua_State *L, ZIO *z, const char *name) {
|
rlm@1
|
509 struct SParser p;
|
rlm@1
|
510 int status;
|
rlm@1
|
511 p.z = z; p.name = name;
|
rlm@1
|
512 luaZ_initbuffer(L, &p.buff);
|
rlm@1
|
513 status = luaD_pcall(L, f_parser, &p, savestack(L, L->top), L->errfunc);
|
rlm@1
|
514 luaZ_freebuffer(L, &p.buff);
|
rlm@1
|
515 return status;
|
rlm@1
|
516 }
|
rlm@1
|
517
|
rlm@1
|
518
|