1 | /* |
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2 | ** $Id: ldo.c,v 2.108.1.3 2013/11/08 18:22:50 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 "lapi.h" |
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18 | #include "ldebug.h" |
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19 | #include "ldo.h" |
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20 | #include "lfunc.h" |
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21 | #include "lgc.h" |
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22 | #include "lmem.h" |
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23 | #include "lobject.h" |
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24 | #include "lopcodes.h" |
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25 | #include "lparser.h" |
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26 | #include "lstate.h" |
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27 | #include "lstring.h" |
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28 | #include "ltable.h" |
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29 | #include "ltm.h" |
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30 | #include "lundump.h" |
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31 | #include "lvm.h" |
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32 | #include "lzio.h" |
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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 | ** {====================================================== |
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39 | ** Error-recovery functions |
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40 | ** ======================================================= |
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41 | */ |
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42 | |
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43 | /* |
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44 | ** LUAI_THROW/LUAI_TRY define how Lua does exception handling. By |
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45 | ** default, Lua handles errors with exceptions when compiling as |
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46 | ** C++ code, with _longjmp/_setjmp when asked to use them, and with |
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47 | ** longjmp/setjmp otherwise. |
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48 | */ |
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49 | #if !defined(LUAI_THROW) |
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50 | |
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51 | #if defined(__cplusplus) && !defined(LUA_USE_LONGJMP) |
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52 | /* C++ exceptions */ |
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53 | #define LUAI_THROW(L,c) throw(c) |
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54 | #define LUAI_TRY(L,c,a) \ |
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55 | try { a } catch(...) { if ((c)->status == 0) (c)->status = -1; } |
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56 | #define luai_jmpbuf int /* dummy variable */ |
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57 | |
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58 | #elif defined(LUA_USE_ULONGJMP) |
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59 | /* in Unix, try _longjmp/_setjmp (more efficient) */ |
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60 | #define LUAI_THROW(L,c) _longjmp((c)->b, 1) |
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61 | #define LUAI_TRY(L,c,a) if (_setjmp((c)->b) == 0) { a } |
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62 | #define luai_jmpbuf jmp_buf |
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63 | |
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64 | #else |
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65 | /* default handling with long jumps */ |
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66 | #define LUAI_THROW(L,c) longjmp((c)->b, 1) |
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67 | #define LUAI_TRY(L,c,a) if (setjmp((c)->b) == 0) { a } |
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68 | #define luai_jmpbuf jmp_buf |
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69 | |
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70 | #endif |
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71 | |
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72 | #endif |
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73 | |
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74 | |
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75 | |
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76 | /* chain list of long jump buffers */ |
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77 | struct lua_longjmp { |
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78 | struct lua_longjmp *previous; |
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79 | luai_jmpbuf b; |
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80 | volatile int status; /* error code */ |
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81 | }; |
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82 | |
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83 | |
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84 | static void seterrorobj (lua_State *L, int errcode, StkId oldtop) { |
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85 | switch (errcode) { |
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86 | case LUA_ERRMEM: { /* memory error? */ |
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87 | setsvalue2s(L, oldtop, G(L)->memerrmsg); /* reuse preregistered msg. */ |
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88 | break; |
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89 | } |
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90 | case LUA_ERRERR: { |
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91 | setsvalue2s(L, oldtop, luaS_newliteral(L, "error in error handling")); |
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92 | break; |
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93 | } |
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94 | default: { |
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95 | setobjs2s(L, oldtop, L->top - 1); /* error message on current top */ |
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96 | break; |
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97 | } |
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98 | } |
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99 | L->top = oldtop + 1; |
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100 | } |
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101 | |
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102 | |
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103 | l_noret luaD_throw (lua_State *L, int errcode) { |
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104 | if (L->errorJmp) { /* thread has an error handler? */ |
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105 | L->errorJmp->status = errcode; /* set status */ |
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106 | LUAI_THROW(L, L->errorJmp); /* jump to it */ |
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107 | } |
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108 | else { /* thread has no error handler */ |
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109 | L->status = cast_byte(errcode); /* mark it as dead */ |
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110 | if (G(L)->mainthread->errorJmp) { /* main thread has a handler? */ |
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111 | setobjs2s(L, G(L)->mainthread->top++, L->top - 1); /* copy error obj. */ |
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112 | luaD_throw(G(L)->mainthread, errcode); /* re-throw in main thread */ |
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113 | } |
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114 | else { /* no handler at all; abort */ |
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115 | if (G(L)->panic) { /* panic function? */ |
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116 | lua_unlock(L); |
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117 | G(L)->panic(L); /* call it (last chance to jump out) */ |
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118 | } |
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119 | abort(); |
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120 | } |
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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 | int luaD_rawrunprotected (lua_State *L, Pfunc f, void *ud) { |
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126 | unsigned short oldnCcalls = L->nCcalls; |
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127 | struct lua_longjmp lj; |
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128 | lj.status = LUA_OK; |
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129 | lj.previous = L->errorJmp; /* chain new error handler */ |
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130 | L->errorJmp = &lj; |
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131 | LUAI_TRY(L, &lj, |
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132 | (*f)(L, ud); |
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133 | ); |
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134 | L->errorJmp = lj.previous; /* restore old error handler */ |
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135 | L->nCcalls = oldnCcalls; |
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136 | return lj.status; |
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137 | } |
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138 | |
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139 | /* }====================================================== */ |
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140 | |
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141 | |
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142 | static void correctstack (lua_State *L, TValue *oldstack) { |
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143 | CallInfo *ci; |
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144 | GCObject *up; |
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145 | L->top = (L->top - oldstack) + L->stack; |
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146 | for (up = L->openupval; up != NULL; up = up->gch.next) |
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147 | gco2uv(up)->v = (gco2uv(up)->v - oldstack) + L->stack; |
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148 | for (ci = L->ci; ci != NULL; ci = ci->previous) { |
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149 | ci->top = (ci->top - oldstack) + L->stack; |
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150 | ci->func = (ci->func - oldstack) + L->stack; |
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151 | if (isLua(ci)) |
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152 | ci->u.l.base = (ci->u.l.base - oldstack) + L->stack; |
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153 | } |
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154 | } |
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155 | |
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156 | |
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157 | /* some space for error handling */ |
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158 | #define ERRORSTACKSIZE (LUAI_MAXSTACK + 200) |
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159 | |
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160 | |
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161 | void luaD_reallocstack (lua_State *L, int newsize) { |
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162 | TValue *oldstack = L->stack; |
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163 | int lim = L->stacksize; |
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164 | lua_assert(newsize <= LUAI_MAXSTACK || newsize == ERRORSTACKSIZE); |
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165 | lua_assert(L->stack_last - L->stack == L->stacksize - EXTRA_STACK); |
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166 | luaM_reallocvector(L, L->stack, L->stacksize, newsize, TValue); |
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167 | for (; lim < newsize; lim++) |
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168 | setnilvalue(L->stack + lim); /* erase new segment */ |
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169 | L->stacksize = newsize; |
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170 | L->stack_last = L->stack + newsize - EXTRA_STACK; |
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171 | correctstack(L, oldstack); |
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172 | } |
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173 | |
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174 | |
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175 | void luaD_growstack (lua_State *L, int n) { |
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176 | int size = L->stacksize; |
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177 | if (size > LUAI_MAXSTACK) /* error after extra size? */ |
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178 | luaD_throw(L, LUA_ERRERR); |
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179 | else { |
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180 | int needed = cast_int(L->top - L->stack) + n + EXTRA_STACK; |
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181 | int newsize = 2 * size; |
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182 | if (newsize > LUAI_MAXSTACK) newsize = LUAI_MAXSTACK; |
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183 | if (newsize < needed) newsize = needed; |
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184 | if (newsize > LUAI_MAXSTACK) { /* stack overflow? */ |
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185 | luaD_reallocstack(L, ERRORSTACKSIZE); |
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186 | luaG_runerror(L, "stack overflow"); |
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187 | } |
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188 | else |
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189 | luaD_reallocstack(L, newsize); |
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190 | } |
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191 | } |
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192 | |
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193 | |
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194 | static int stackinuse (lua_State *L) { |
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195 | CallInfo *ci; |
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196 | StkId lim = L->top; |
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197 | for (ci = L->ci; ci != NULL; ci = ci->previous) { |
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198 | lua_assert(ci->top <= L->stack_last); |
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199 | if (lim < ci->top) lim = ci->top; |
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200 | } |
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201 | return cast_int(lim - L->stack) + 1; /* part of stack in use */ |
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202 | } |
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203 | |
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204 | |
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205 | void luaD_shrinkstack (lua_State *L) { |
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206 | int inuse = stackinuse(L); |
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207 | int goodsize = inuse + (inuse / 8) + 2*EXTRA_STACK; |
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208 | if (goodsize > LUAI_MAXSTACK) goodsize = LUAI_MAXSTACK; |
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209 | if (inuse > LUAI_MAXSTACK || /* handling stack overflow? */ |
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210 | goodsize >= L->stacksize) /* would grow instead of shrink? */ |
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211 | condmovestack(L); /* don't change stack (change only for debugging) */ |
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212 | else |
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213 | luaD_reallocstack(L, goodsize); /* shrink it */ |
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214 | } |
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215 | |
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216 | |
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217 | void luaD_hook (lua_State *L, int event, int line) { |
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218 | lua_Hook hook = L->hook; |
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219 | if (hook && L->allowhook) { |
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220 | CallInfo *ci = L->ci; |
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221 | ptrdiff_t top = savestack(L, L->top); |
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222 | ptrdiff_t ci_top = savestack(L, ci->top); |
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223 | lua_Debug ar; |
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224 | ar.event = event; |
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225 | ar.currentline = line; |
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226 | ar.i_ci = ci; |
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227 | luaD_checkstack(L, LUA_MINSTACK); /* ensure minimum stack size */ |
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228 | ci->top = L->top + LUA_MINSTACK; |
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229 | lua_assert(ci->top <= L->stack_last); |
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230 | L->allowhook = 0; /* cannot call hooks inside a hook */ |
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231 | ci->callstatus |= CIST_HOOKED; |
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232 | lua_unlock(L); |
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233 | (*hook)(L, &ar); |
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234 | lua_lock(L); |
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235 | lua_assert(!L->allowhook); |
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236 | L->allowhook = 1; |
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237 | ci->top = restorestack(L, ci_top); |
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238 | L->top = restorestack(L, top); |
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239 | ci->callstatus &= ~CIST_HOOKED; |
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240 | } |
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241 | } |
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242 | |
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243 | |
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244 | static void callhook (lua_State *L, CallInfo *ci) { |
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245 | int hook = LUA_HOOKCALL; |
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246 | ci->u.l.savedpc++; /* hooks assume 'pc' is already incremented */ |
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247 | if (isLua(ci->previous) && |
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248 | GET_OPCODE(*(ci->previous->u.l.savedpc - 1)) == OP_TAILCALL) { |
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249 | ci->callstatus |= CIST_TAIL; |
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250 | hook = LUA_HOOKTAILCALL; |
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251 | } |
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252 | luaD_hook(L, hook, -1); |
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253 | ci->u.l.savedpc--; /* correct 'pc' */ |
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254 | } |
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255 | |
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256 | |
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257 | static StkId adjust_varargs (lua_State *L, Proto *p, int actual) { |
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258 | int i; |
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259 | int nfixargs = p->numparams; |
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260 | StkId base, fixed; |
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261 | lua_assert(actual >= nfixargs); |
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262 | /* move fixed parameters to final position */ |
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263 | luaD_checkstack(L, p->maxstacksize); /* check again for new 'base' */ |
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264 | fixed = L->top - actual; /* first fixed argument */ |
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265 | base = L->top; /* final position of first argument */ |
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266 | for (i=0; i<nfixargs; i++) { |
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267 | setobjs2s(L, L->top++, fixed + i); |
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268 | setnilvalue(fixed + i); |
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269 | } |
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270 | return base; |
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271 | } |
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272 | |
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273 | |
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274 | static StkId tryfuncTM (lua_State *L, StkId func) { |
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275 | const TValue *tm = luaT_gettmbyobj(L, func, TM_CALL); |
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276 | StkId p; |
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277 | ptrdiff_t funcr = savestack(L, func); |
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278 | if (!ttisfunction(tm)) |
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279 | luaG_typeerror(L, func, "call"); |
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280 | /* Open a hole inside the stack at `func' */ |
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281 | for (p = L->top; p > func; p--) setobjs2s(L, p, p-1); |
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282 | incr_top(L); |
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283 | func = restorestack(L, funcr); /* previous call may change stack */ |
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284 | setobj2s(L, func, tm); /* tag method is the new function to be called */ |
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285 | return func; |
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286 | } |
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287 | |
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288 | |
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289 | |
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290 | #define next_ci(L) (L->ci = (L->ci->next ? L->ci->next : luaE_extendCI(L))) |
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291 | |
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292 | |
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293 | /* |
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294 | ** returns true if function has been executed (C function) |
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295 | */ |
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296 | int luaD_precall (lua_State *L, StkId func, int nresults) { |
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297 | lua_CFunction f; |
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298 | CallInfo *ci; |
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299 | int n; /* number of arguments (Lua) or returns (C) */ |
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300 | ptrdiff_t funcr = savestack(L, func); |
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301 | switch (ttype(func)) { |
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302 | case LUA_TLCF: /* light C function */ |
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303 | f = fvalue(func); |
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304 | goto Cfunc; |
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305 | case LUA_TCCL: { /* C closure */ |
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306 | f = clCvalue(func)->f; |
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307 | Cfunc: |
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308 | luaD_checkstack(L, LUA_MINSTACK); /* ensure minimum stack size */ |
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309 | ci = next_ci(L); /* now 'enter' new function */ |
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310 | ci->nresults = nresults; |
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311 | ci->func = restorestack(L, funcr); |
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312 | ci->top = L->top + LUA_MINSTACK; |
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313 | lua_assert(ci->top <= L->stack_last); |
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314 | ci->callstatus = 0; |
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315 | luaC_checkGC(L); /* stack grow uses memory */ |
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316 | if (L->hookmask & LUA_MASKCALL) |
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317 | luaD_hook(L, LUA_HOOKCALL, -1); |
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318 | lua_unlock(L); |
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319 | n = (*f)(L); /* do the actual call */ |
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320 | lua_lock(L); |
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321 | api_checknelems(L, n); |
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322 | luaD_poscall(L, L->top - n); |
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323 | return 1; |
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324 | } |
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325 | case LUA_TLCL: { /* Lua function: prepare its call */ |
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326 | StkId base; |
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327 | Proto *p = clLvalue(func)->p; |
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328 | n = cast_int(L->top - func) - 1; /* number of real arguments */ |
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329 | luaD_checkstack(L, p->maxstacksize); |
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330 | for (; n < p->numparams; n++) |
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331 | setnilvalue(L->top++); /* complete missing arguments */ |
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332 | if (!p->is_vararg) { |
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333 | func = restorestack(L, funcr); |
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334 | base = func + 1; |
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335 | } |
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336 | else { |
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337 | base = adjust_varargs(L, p, n); |
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338 | func = restorestack(L, funcr); /* previous call can change stack */ |
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339 | } |
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340 | ci = next_ci(L); /* now 'enter' new function */ |
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341 | ci->nresults = nresults; |
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342 | ci->func = func; |
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343 | ci->u.l.base = base; |
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344 | ci->top = base + p->maxstacksize; |
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345 | lua_assert(ci->top <= L->stack_last); |
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346 | ci->u.l.savedpc = p->code; /* starting point */ |
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347 | ci->callstatus = CIST_LUA; |
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348 | L->top = ci->top; |
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349 | luaC_checkGC(L); /* stack grow uses memory */ |
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350 | if (L->hookmask & LUA_MASKCALL) |
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351 | callhook(L, ci); |
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352 | return 0; |
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353 | } |
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354 | default: { /* not a function */ |
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355 | func = tryfuncTM(L, func); /* retry with 'function' tag method */ |
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356 | return luaD_precall(L, func, nresults); /* now it must be a function */ |
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357 | } |
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358 | } |
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359 | } |
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360 | |
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361 | |
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362 | int luaD_poscall (lua_State *L, StkId firstResult) { |
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363 | StkId res; |
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364 | int wanted, i; |
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365 | CallInfo *ci = L->ci; |
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366 | if (L->hookmask & (LUA_MASKRET | LUA_MASKLINE)) { |
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367 | if (L->hookmask & LUA_MASKRET) { |
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368 | ptrdiff_t fr = savestack(L, firstResult); /* hook may change stack */ |
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369 | luaD_hook(L, LUA_HOOKRET, -1); |
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370 | firstResult = restorestack(L, fr); |
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371 | } |
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372 | L->oldpc = ci->previous->u.l.savedpc; /* 'oldpc' for caller function */ |
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373 | } |
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374 | res = ci->func; /* res == final position of 1st result */ |
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375 | wanted = ci->nresults; |
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376 | L->ci = ci = ci->previous; /* back to caller */ |
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377 | /* move results to correct place */ |
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378 | for (i = wanted; i != 0 && firstResult < L->top; i--) |
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379 | setobjs2s(L, res++, firstResult++); |
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380 | while (i-- > 0) |
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381 | setnilvalue(res++); |
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382 | L->top = res; |
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383 | return (wanted - LUA_MULTRET); /* 0 iff wanted == LUA_MULTRET */ |
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384 | } |
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385 | |
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386 | |
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387 | /* |
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388 | ** Call a function (C or Lua). The function to be called is at *func. |
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389 | ** The arguments are on the stack, right after the function. |
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390 | ** When returns, all the results are on the stack, starting at the original |
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391 | ** function position. |
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392 | */ |
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393 | void luaD_call (lua_State *L, StkId func, int nResults, int allowyield) { |
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394 | if (++L->nCcalls >= LUAI_MAXCCALLS) { |
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395 | if (L->nCcalls == LUAI_MAXCCALLS) |
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396 | luaG_runerror(L, "C stack overflow"); |
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397 | else if (L->nCcalls >= (LUAI_MAXCCALLS + (LUAI_MAXCCALLS>>3))) |
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398 | luaD_throw(L, LUA_ERRERR); /* error while handing stack error */ |
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399 | } |
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400 | if (!allowyield) L->nny++; |
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401 | if (!luaD_precall(L, func, nResults)) /* is a Lua function? */ |
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402 | luaV_execute(L); /* call it */ |
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403 | if (!allowyield) L->nny--; |
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404 | L->nCcalls--; |
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405 | } |
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406 | |
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407 | |
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408 | static void finishCcall (lua_State *L) { |
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409 | CallInfo *ci = L->ci; |
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410 | int n; |
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411 | lua_assert(ci->u.c.k != NULL); /* must have a continuation */ |
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412 | lua_assert(L->nny == 0); |
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413 | if (ci->callstatus & CIST_YPCALL) { /* was inside a pcall? */ |
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414 | ci->callstatus &= ~CIST_YPCALL; /* finish 'lua_pcall' */ |
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415 | L->errfunc = ci->u.c.old_errfunc; |
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416 | } |
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417 | /* finish 'lua_callk'/'lua_pcall' */ |
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418 | adjustresults(L, ci->nresults); |
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419 | /* call continuation function */ |
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420 | if (!(ci->callstatus & CIST_STAT)) /* no call status? */ |
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421 | ci->u.c.status = LUA_YIELD; /* 'default' status */ |
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422 | lua_assert(ci->u.c.status != LUA_OK); |
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423 | ci->callstatus = (ci->callstatus & ~(CIST_YPCALL | CIST_STAT)) | CIST_YIELDED; |
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424 | lua_unlock(L); |
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425 | n = (*ci->u.c.k)(L); |
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426 | lua_lock(L); |
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427 | api_checknelems(L, n); |
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428 | /* finish 'luaD_precall' */ |
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429 | luaD_poscall(L, L->top - n); |
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430 | } |
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431 | |
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432 | |
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433 | static void unroll (lua_State *L, void *ud) { |
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434 | UNUSED(ud); |
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435 | for (;;) { |
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436 | if (L->ci == &L->base_ci) /* stack is empty? */ |
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437 | return; /* coroutine finished normally */ |
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438 | if (!isLua(L->ci)) /* C function? */ |
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439 | finishCcall(L); |
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440 | else { /* Lua function */ |
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441 | luaV_finishOp(L); /* finish interrupted instruction */ |
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442 | luaV_execute(L); /* execute down to higher C 'boundary' */ |
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443 | } |
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444 | } |
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445 | } |
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446 | |
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447 | |
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448 | /* |
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449 | ** check whether thread has a suspended protected call |
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450 | */ |
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451 | static CallInfo *findpcall (lua_State *L) { |
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452 | CallInfo *ci; |
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453 | for (ci = L->ci; ci != NULL; ci = ci->previous) { /* search for a pcall */ |
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454 | if (ci->callstatus & CIST_YPCALL) |
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455 | return ci; |
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456 | } |
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457 | return NULL; /* no pending pcall */ |
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458 | } |
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459 | |
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460 | |
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461 | static int recover (lua_State *L, int status) { |
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462 | StkId oldtop; |
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463 | CallInfo *ci = findpcall(L); |
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464 | if (ci == NULL) return 0; /* no recovery point */ |
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465 | /* "finish" luaD_pcall */ |
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466 | oldtop = restorestack(L, ci->extra); |
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467 | luaF_close(L, oldtop); |
---|
468 | seterrorobj(L, status, oldtop); |
---|
469 | L->ci = ci; |
---|
470 | L->allowhook = ci->u.c.old_allowhook; |
---|
471 | L->nny = 0; /* should be zero to be yieldable */ |
---|
472 | luaD_shrinkstack(L); |
---|
473 | L->errfunc = ci->u.c.old_errfunc; |
---|
474 | ci->callstatus |= CIST_STAT; /* call has error status */ |
---|
475 | ci->u.c.status = status; /* (here it is) */ |
---|
476 | return 1; /* continue running the coroutine */ |
---|
477 | } |
---|
478 | |
---|
479 | |
---|
480 | /* |
---|
481 | ** signal an error in the call to 'resume', not in the execution of the |
---|
482 | ** coroutine itself. (Such errors should not be handled by any coroutine |
---|
483 | ** error handler and should not kill the coroutine.) |
---|
484 | */ |
---|
485 | static l_noret resume_error (lua_State *L, const char *msg, StkId firstArg) { |
---|
486 | L->top = firstArg; /* remove args from the stack */ |
---|
487 | setsvalue2s(L, L->top, luaS_new(L, msg)); /* push error message */ |
---|
488 | api_incr_top(L); |
---|
489 | luaD_throw(L, -1); /* jump back to 'lua_resume' */ |
---|
490 | } |
---|
491 | |
---|
492 | |
---|
493 | /* |
---|
494 | ** do the work for 'lua_resume' in protected mode |
---|
495 | */ |
---|
496 | static void resume (lua_State *L, void *ud) { |
---|
497 | int nCcalls = L->nCcalls; |
---|
498 | StkId firstArg = cast(StkId, ud); |
---|
499 | CallInfo *ci = L->ci; |
---|
500 | if (nCcalls >= LUAI_MAXCCALLS) |
---|
501 | resume_error(L, "C stack overflow", firstArg); |
---|
502 | if (L->status == LUA_OK) { /* may be starting a coroutine */ |
---|
503 | if (ci != &L->base_ci) /* not in base level? */ |
---|
504 | resume_error(L, "cannot resume non-suspended coroutine", firstArg); |
---|
505 | /* coroutine is in base level; start running it */ |
---|
506 | if (!luaD_precall(L, firstArg - 1, LUA_MULTRET)) /* Lua function? */ |
---|
507 | luaV_execute(L); /* call it */ |
---|
508 | } |
---|
509 | else if (L->status != LUA_YIELD) |
---|
510 | resume_error(L, "cannot resume dead coroutine", firstArg); |
---|
511 | else { /* resuming from previous yield */ |
---|
512 | L->status = LUA_OK; |
---|
513 | ci->func = restorestack(L, ci->extra); |
---|
514 | if (isLua(ci)) /* yielded inside a hook? */ |
---|
515 | luaV_execute(L); /* just continue running Lua code */ |
---|
516 | else { /* 'common' yield */ |
---|
517 | if (ci->u.c.k != NULL) { /* does it have a continuation? */ |
---|
518 | int n; |
---|
519 | ci->u.c.status = LUA_YIELD; /* 'default' status */ |
---|
520 | ci->callstatus |= CIST_YIELDED; |
---|
521 | lua_unlock(L); |
---|
522 | n = (*ci->u.c.k)(L); /* call continuation */ |
---|
523 | lua_lock(L); |
---|
524 | api_checknelems(L, n); |
---|
525 | firstArg = L->top - n; /* yield results come from continuation */ |
---|
526 | } |
---|
527 | luaD_poscall(L, firstArg); /* finish 'luaD_precall' */ |
---|
528 | } |
---|
529 | unroll(L, NULL); |
---|
530 | } |
---|
531 | lua_assert(nCcalls == L->nCcalls); |
---|
532 | } |
---|
533 | |
---|
534 | |
---|
535 | LUA_API int lua_resume (lua_State *L, lua_State *from, int nargs) { |
---|
536 | int status; |
---|
537 | int oldnny = L->nny; /* save 'nny' */ |
---|
538 | lua_lock(L); |
---|
539 | luai_userstateresume(L, nargs); |
---|
540 | L->nCcalls = (from) ? from->nCcalls + 1 : 1; |
---|
541 | L->nny = 0; /* allow yields */ |
---|
542 | api_checknelems(L, (L->status == LUA_OK) ? nargs + 1 : nargs); |
---|
543 | status = luaD_rawrunprotected(L, resume, L->top - nargs); |
---|
544 | if (status == -1) /* error calling 'lua_resume'? */ |
---|
545 | status = LUA_ERRRUN; |
---|
546 | else { /* yield or regular error */ |
---|
547 | while (status != LUA_OK && status != LUA_YIELD) { /* error? */ |
---|
548 | if (recover(L, status)) /* recover point? */ |
---|
549 | status = luaD_rawrunprotected(L, unroll, NULL); /* run continuation */ |
---|
550 | else { /* unrecoverable error */ |
---|
551 | L->status = cast_byte(status); /* mark thread as `dead' */ |
---|
552 | seterrorobj(L, status, L->top); |
---|
553 | L->ci->top = L->top; |
---|
554 | break; |
---|
555 | } |
---|
556 | } |
---|
557 | lua_assert(status == L->status); |
---|
558 | } |
---|
559 | L->nny = oldnny; /* restore 'nny' */ |
---|
560 | L->nCcalls--; |
---|
561 | lua_assert(L->nCcalls == ((from) ? from->nCcalls : 0)); |
---|
562 | lua_unlock(L); |
---|
563 | return status; |
---|
564 | } |
---|
565 | |
---|
566 | |
---|
567 | LUA_API int lua_yieldk (lua_State *L, int nresults, int ctx, lua_CFunction k) { |
---|
568 | CallInfo *ci = L->ci; |
---|
569 | luai_userstateyield(L, nresults); |
---|
570 | lua_lock(L); |
---|
571 | api_checknelems(L, nresults); |
---|
572 | if (L->nny > 0) { |
---|
573 | if (L != G(L)->mainthread) |
---|
574 | luaG_runerror(L, "attempt to yield across a C-call boundary"); |
---|
575 | else |
---|
576 | luaG_runerror(L, "attempt to yield from outside a coroutine"); |
---|
577 | } |
---|
578 | L->status = LUA_YIELD; |
---|
579 | ci->extra = savestack(L, ci->func); /* save current 'func' */ |
---|
580 | if (isLua(ci)) { /* inside a hook? */ |
---|
581 | api_check(L, k == NULL, "hooks cannot continue after yielding"); |
---|
582 | } |
---|
583 | else { |
---|
584 | if ((ci->u.c.k = k) != NULL) /* is there a continuation? */ |
---|
585 | ci->u.c.ctx = ctx; /* save context */ |
---|
586 | ci->func = L->top - nresults - 1; /* protect stack below results */ |
---|
587 | luaD_throw(L, LUA_YIELD); |
---|
588 | } |
---|
589 | lua_assert(ci->callstatus & CIST_HOOKED); /* must be inside a hook */ |
---|
590 | lua_unlock(L); |
---|
591 | return 0; /* return to 'luaD_hook' */ |
---|
592 | } |
---|
593 | |
---|
594 | |
---|
595 | int luaD_pcall (lua_State *L, Pfunc func, void *u, |
---|
596 | ptrdiff_t old_top, ptrdiff_t ef) { |
---|
597 | int status; |
---|
598 | CallInfo *old_ci = L->ci; |
---|
599 | lu_byte old_allowhooks = L->allowhook; |
---|
600 | unsigned short old_nny = L->nny; |
---|
601 | ptrdiff_t old_errfunc = L->errfunc; |
---|
602 | L->errfunc = ef; |
---|
603 | status = luaD_rawrunprotected(L, func, u); |
---|
604 | if (status != LUA_OK) { /* an error occurred? */ |
---|
605 | StkId oldtop = restorestack(L, old_top); |
---|
606 | luaF_close(L, oldtop); /* close possible pending closures */ |
---|
607 | seterrorobj(L, status, oldtop); |
---|
608 | L->ci = old_ci; |
---|
609 | L->allowhook = old_allowhooks; |
---|
610 | L->nny = old_nny; |
---|
611 | luaD_shrinkstack(L); |
---|
612 | } |
---|
613 | L->errfunc = old_errfunc; |
---|
614 | return status; |
---|
615 | } |
---|
616 | |
---|
617 | |
---|
618 | |
---|
619 | /* |
---|
620 | ** Execute a protected parser. |
---|
621 | */ |
---|
622 | struct SParser { /* data to `f_parser' */ |
---|
623 | ZIO *z; |
---|
624 | Mbuffer buff; /* dynamic structure used by the scanner */ |
---|
625 | Dyndata dyd; /* dynamic structures used by the parser */ |
---|
626 | const char *mode; |
---|
627 | const char *name; |
---|
628 | }; |
---|
629 | |
---|
630 | |
---|
631 | static void checkmode (lua_State *L, const char *mode, const char *x) { |
---|
632 | if (mode && strchr(mode, x[0]) == NULL) { |
---|
633 | luaO_pushfstring(L, |
---|
634 | "attempt to load a %s chunk (mode is " LUA_QS ")", x, mode); |
---|
635 | luaD_throw(L, LUA_ERRSYNTAX); |
---|
636 | } |
---|
637 | } |
---|
638 | |
---|
639 | |
---|
640 | static void f_parser (lua_State *L, void *ud) { |
---|
641 | int i; |
---|
642 | Closure *cl; |
---|
643 | struct SParser *p = cast(struct SParser *, ud); |
---|
644 | int c = zgetc(p->z); /* read first character */ |
---|
645 | if (c == LUA_SIGNATURE[0]) { |
---|
646 | checkmode(L, p->mode, "binary"); |
---|
647 | cl = luaU_undump(L, p->z, &p->buff, p->name); |
---|
648 | } |
---|
649 | else { |
---|
650 | checkmode(L, p->mode, "text"); |
---|
651 | cl = luaY_parser(L, p->z, &p->buff, &p->dyd, p->name, c); |
---|
652 | } |
---|
653 | lua_assert(cl->l.nupvalues == cl->l.p->sizeupvalues); |
---|
654 | for (i = 0; i < cl->l.nupvalues; i++) { /* initialize upvalues */ |
---|
655 | UpVal *up = luaF_newupval(L); |
---|
656 | cl->l.upvals[i] = up; |
---|
657 | luaC_objbarrier(L, cl, up); |
---|
658 | } |
---|
659 | } |
---|
660 | |
---|
661 | |
---|
662 | int luaD_protectedparser (lua_State *L, ZIO *z, const char *name, |
---|
663 | const char *mode) { |
---|
664 | struct SParser p; |
---|
665 | int status; |
---|
666 | L->nny++; /* cannot yield during parsing */ |
---|
667 | p.z = z; p.name = name; p.mode = mode; |
---|
668 | p.dyd.actvar.arr = NULL; p.dyd.actvar.size = 0; |
---|
669 | p.dyd.gt.arr = NULL; p.dyd.gt.size = 0; |
---|
670 | p.dyd.label.arr = NULL; p.dyd.label.size = 0; |
---|
671 | luaZ_initbuffer(L, &p.buff); |
---|
672 | status = luaD_pcall(L, f_parser, &p, savestack(L, L->top), L->errfunc); |
---|
673 | luaZ_freebuffer(L, &p.buff); |
---|
674 | luaM_freearray(L, p.dyd.actvar.arr, p.dyd.actvar.size); |
---|
675 | luaM_freearray(L, p.dyd.gt.arr, p.dyd.gt.size); |
---|
676 | luaM_freearray(L, p.dyd.label.arr, p.dyd.label.size); |
---|
677 | L->nny--; |
---|
678 | return status; |
---|
679 | } |
---|
680 | |
---|
681 | |
---|