summaryrefslogtreecommitdiff
path: root/src/ldo.c
diff options
context:
space:
mode:
authorJeffrey Armstrong <jeff@approximatrix.com>2020-09-28 20:25:16 -0400
committerJeffrey Armstrong <jeff@approximatrix.com>2020-09-28 20:25:16 -0400
commit334ee3f66a7aad17c9865bd9952b0c501b97721a (patch)
tree0ee71269e8c482e6a2df9cbb37dbe15302136799 /src/ldo.c
downloadrainbow-lua-334ee3f66a7aad17c9865bd9952b0c501b97721a.zip
rainbow-lua-334ee3f66a7aad17c9865bd9952b0c501b97721a.tar.gz
Initial import based on Lua 5.3.5
Diffstat (limited to 'src/ldo.c')
-rw-r--r--src/ldo.c802
1 files changed, 802 insertions, 0 deletions
diff --git a/src/ldo.c b/src/ldo.c
new file mode 100644
index 0000000..316e45c
--- /dev/null
+++ b/src/ldo.c
@@ -0,0 +1,802 @@
+/*
+** $Id: ldo.c,v 2.157.1.1 2017/04/19 17:20:42 roberto Exp $
+** Stack and Call structure of Lua
+** See Copyright Notice in lua.h
+*/
+
+#define ldo_c
+#define LUA_CORE
+
+#include "lprefix.h"
+
+
+#include <setjmp.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "lua.h"
+
+#include "lapi.h"
+#include "ldebug.h"
+#include "ldo.h"
+#include "lfunc.h"
+#include "lgc.h"
+#include "lmem.h"
+#include "lobject.h"
+#include "lopcodes.h"
+#include "lparser.h"
+#include "lstate.h"
+#include "lstring.h"
+#include "ltable.h"
+#include "ltm.h"
+#include "lundump.h"
+#include "lvm.h"
+#include "lzio.h"
+
+
+
+#define errorstatus(s) ((s) > LUA_YIELD)
+
+
+/*
+** {======================================================
+** Error-recovery functions
+** =======================================================
+*/
+
+/*
+** LUAI_THROW/LUAI_TRY define how Lua does exception handling. By
+** default, Lua handles errors with exceptions when compiling as
+** C++ code, with _longjmp/_setjmp when asked to use them, and with
+** longjmp/setjmp otherwise.
+*/
+#if !defined(LUAI_THROW) /* { */
+
+#if defined(__cplusplus) && !defined(LUA_USE_LONGJMP) /* { */
+
+/* C++ exceptions */
+#define LUAI_THROW(L,c) throw(c)
+#define LUAI_TRY(L,c,a) \
+ try { a } catch(...) { if ((c)->status == 0) (c)->status = -1; }
+#define luai_jmpbuf int /* dummy variable */
+
+#elif defined(LUA_USE_POSIX) /* }{ */
+
+/* in POSIX, try _longjmp/_setjmp (more efficient) */
+#define LUAI_THROW(L,c) _longjmp((c)->b, 1)
+#define LUAI_TRY(L,c,a) if (_setjmp((c)->b) == 0) { a }
+#define luai_jmpbuf jmp_buf
+
+#else /* }{ */
+
+/* ISO C handling with long jumps */
+#define LUAI_THROW(L,c) longjmp((c)->b, 1)
+#define LUAI_TRY(L,c,a) if (setjmp((c)->b) == 0) { a }
+#define luai_jmpbuf jmp_buf
+
+#endif /* } */
+
+#endif /* } */
+
+
+
+/* chain list of long jump buffers */
+struct lua_longjmp {
+ struct lua_longjmp *previous;
+ luai_jmpbuf b;
+ volatile int status; /* error code */
+};
+
+
+static void seterrorobj (lua_State *L, int errcode, StkId oldtop) {
+ switch (errcode) {
+ case LUA_ERRMEM: { /* memory error? */
+ setsvalue2s(L, oldtop, G(L)->memerrmsg); /* reuse preregistered msg. */
+ break;
+ }
+ case LUA_ERRERR: {
+ setsvalue2s(L, oldtop, luaS_newliteral(L, "error in error handling"));
+ break;
+ }
+ default: {
+ setobjs2s(L, oldtop, L->top - 1); /* error message on current top */
+ break;
+ }
+ }
+ L->top = oldtop + 1;
+}
+
+
+l_noret luaD_throw (lua_State *L, int errcode) {
+ if (L->errorJmp) { /* thread has an error handler? */
+ L->errorJmp->status = errcode; /* set status */
+ LUAI_THROW(L, L->errorJmp); /* jump to it */
+ }
+ else { /* thread has no error handler */
+ global_State *g = G(L);
+ L->status = cast_byte(errcode); /* mark it as dead */
+ if (g->mainthread->errorJmp) { /* main thread has a handler? */
+ setobjs2s(L, g->mainthread->top++, L->top - 1); /* copy error obj. */
+ luaD_throw(g->mainthread, errcode); /* re-throw in main thread */
+ }
+ else { /* no handler at all; abort */
+ if (g->panic) { /* panic function? */
+ seterrorobj(L, errcode, L->top); /* assume EXTRA_STACK */
+ if (L->ci->top < L->top)
+ L->ci->top = L->top; /* pushing msg. can break this invariant */
+ lua_unlock(L);
+ g->panic(L); /* call panic function (last chance to jump out) */
+ }
+ abort();
+ }
+ }
+}
+
+
+int luaD_rawrunprotected (lua_State *L, Pfunc f, void *ud) {
+ unsigned short oldnCcalls = L->nCcalls;
+ struct lua_longjmp lj;
+ lj.status = LUA_OK;
+ lj.previous = L->errorJmp; /* chain new error handler */
+ L->errorJmp = &lj;
+ LUAI_TRY(L, &lj,
+ (*f)(L, ud);
+ );
+ L->errorJmp = lj.previous; /* restore old error handler */
+ L->nCcalls = oldnCcalls;
+ return lj.status;
+}
+
+/* }====================================================== */
+
+
+/*
+** {==================================================================
+** Stack reallocation
+** ===================================================================
+*/
+static void correctstack (lua_State *L, TValue *oldstack) {
+ CallInfo *ci;
+ UpVal *up;
+ L->top = (L->top - oldstack) + L->stack;
+ for (up = L->openupval; up != NULL; up = up->u.open.next)
+ up->v = (up->v - oldstack) + L->stack;
+ for (ci = L->ci; ci != NULL; ci = ci->previous) {
+ ci->top = (ci->top - oldstack) + L->stack;
+ ci->func = (ci->func - oldstack) + L->stack;
+ if (isLua(ci))
+ ci->u.l.base = (ci->u.l.base - oldstack) + L->stack;
+ }
+}
+
+
+/* some space for error handling */
+#define ERRORSTACKSIZE (LUAI_MAXSTACK + 200)
+
+
+void luaD_reallocstack (lua_State *L, int newsize) {
+ TValue *oldstack = L->stack;
+ int lim = L->stacksize;
+ lua_assert(newsize <= LUAI_MAXSTACK || newsize == ERRORSTACKSIZE);
+ lua_assert(L->stack_last - L->stack == L->stacksize - EXTRA_STACK);
+ luaM_reallocvector(L, L->stack, L->stacksize, newsize, TValue);
+ for (; lim < newsize; lim++)
+ setnilvalue(L->stack + lim); /* erase new segment */
+ L->stacksize = newsize;
+ L->stack_last = L->stack + newsize - EXTRA_STACK;
+ correctstack(L, oldstack);
+}
+
+
+void luaD_growstack (lua_State *L, int n) {
+ int size = L->stacksize;
+ if (size > LUAI_MAXSTACK) /* error after extra size? */
+ luaD_throw(L, LUA_ERRERR);
+ else {
+ int needed = cast_int(L->top - L->stack) + n + EXTRA_STACK;
+ int newsize = 2 * size;
+ if (newsize > LUAI_MAXSTACK) newsize = LUAI_MAXSTACK;
+ if (newsize < needed) newsize = needed;
+ if (newsize > LUAI_MAXSTACK) { /* stack overflow? */
+ luaD_reallocstack(L, ERRORSTACKSIZE);
+ luaG_runerror(L, "stack overflow");
+ }
+ else
+ luaD_reallocstack(L, newsize);
+ }
+}
+
+
+static int stackinuse (lua_State *L) {
+ CallInfo *ci;
+ StkId lim = L->top;
+ for (ci = L->ci; ci != NULL; ci = ci->previous) {
+ if (lim < ci->top) lim = ci->top;
+ }
+ lua_assert(lim <= L->stack_last);
+ return cast_int(lim - L->stack) + 1; /* part of stack in use */
+}
+
+
+void luaD_shrinkstack (lua_State *L) {
+ int inuse = stackinuse(L);
+ int goodsize = inuse + (inuse / 8) + 2*EXTRA_STACK;
+ if (goodsize > LUAI_MAXSTACK)
+ goodsize = LUAI_MAXSTACK; /* respect stack limit */
+ if (L->stacksize > LUAI_MAXSTACK) /* had been handling stack overflow? */
+ luaE_freeCI(L); /* free all CIs (list grew because of an error) */
+ else
+ luaE_shrinkCI(L); /* shrink list */
+ /* if thread is currently not handling a stack overflow and its
+ good size is smaller than current size, shrink its stack */
+ if (inuse <= (LUAI_MAXSTACK - EXTRA_STACK) &&
+ goodsize < L->stacksize)
+ luaD_reallocstack(L, goodsize);
+ else /* don't change stack */
+ condmovestack(L,{},{}); /* (change only for debugging) */
+}
+
+
+void luaD_inctop (lua_State *L) {
+ luaD_checkstack(L, 1);
+ L->top++;
+}
+
+/* }================================================================== */
+
+
+/*
+** Call a hook for the given event. Make sure there is a hook to be
+** called. (Both 'L->hook' and 'L->hookmask', which triggers this
+** function, can be changed asynchronously by signals.)
+*/
+void luaD_hook (lua_State *L, int event, int line) {
+ lua_Hook hook = L->hook;
+ if (hook && L->allowhook) { /* make sure there is a hook */
+ CallInfo *ci = L->ci;
+ ptrdiff_t top = savestack(L, L->top);
+ ptrdiff_t ci_top = savestack(L, ci->top);
+ lua_Debug ar;
+ ar.event = event;
+ ar.currentline = line;
+ ar.i_ci = ci;
+ luaD_checkstack(L, LUA_MINSTACK); /* ensure minimum stack size */
+ ci->top = L->top + LUA_MINSTACK;
+ lua_assert(ci->top <= L->stack_last);
+ L->allowhook = 0; /* cannot call hooks inside a hook */
+ ci->callstatus |= CIST_HOOKED;
+ lua_unlock(L);
+ (*hook)(L, &ar);
+ lua_lock(L);
+ lua_assert(!L->allowhook);
+ L->allowhook = 1;
+ ci->top = restorestack(L, ci_top);
+ L->top = restorestack(L, top);
+ ci->callstatus &= ~CIST_HOOKED;
+ }
+}
+
+
+static void callhook (lua_State *L, CallInfo *ci) {
+ int hook = LUA_HOOKCALL;
+ ci->u.l.savedpc++; /* hooks assume 'pc' is already incremented */
+ if (isLua(ci->previous) &&
+ GET_OPCODE(*(ci->previous->u.l.savedpc - 1)) == OP_TAILCALL) {
+ ci->callstatus |= CIST_TAIL;
+ hook = LUA_HOOKTAILCALL;
+ }
+ luaD_hook(L, hook, -1);
+ ci->u.l.savedpc--; /* correct 'pc' */
+}
+
+
+static StkId adjust_varargs (lua_State *L, Proto *p, int actual) {
+ int i;
+ int nfixargs = p->numparams;
+ StkId base, fixed;
+ /* move fixed parameters to final position */
+ fixed = L->top - actual; /* first fixed argument */
+ base = L->top; /* final position of first argument */
+ for (i = 0; i < nfixargs && i < actual; i++) {
+ setobjs2s(L, L->top++, fixed + i);
+ setnilvalue(fixed + i); /* erase original copy (for GC) */
+ }
+ for (; i < nfixargs; i++)
+ setnilvalue(L->top++); /* complete missing arguments */
+ return base;
+}
+
+
+/*
+** Check whether __call metafield of 'func' is a function. If so, put
+** it in stack below original 'func' so that 'luaD_precall' can call
+** it. Raise an error if __call metafield is not a function.
+*/
+static void tryfuncTM (lua_State *L, StkId func) {
+ const TValue *tm = luaT_gettmbyobj(L, func, TM_CALL);
+ StkId p;
+ if (!ttisfunction(tm))
+ luaG_typeerror(L, func, "call");
+ /* Open a hole inside the stack at 'func' */
+ for (p = L->top; p > func; p--)
+ setobjs2s(L, p, p-1);
+ L->top++; /* slot ensured by caller */
+ setobj2s(L, func, tm); /* tag method is the new function to be called */
+}
+
+
+/*
+** Given 'nres' results at 'firstResult', move 'wanted' of them to 'res'.
+** Handle most typical cases (zero results for commands, one result for
+** expressions, multiple results for tail calls/single parameters)
+** separated.
+*/
+static int moveresults (lua_State *L, const TValue *firstResult, StkId res,
+ int nres, int wanted) {
+ switch (wanted) { /* handle typical cases separately */
+ case 0: break; /* nothing to move */
+ case 1: { /* one result needed */
+ if (nres == 0) /* no results? */
+ firstResult = luaO_nilobject; /* adjust with nil */
+ setobjs2s(L, res, firstResult); /* move it to proper place */
+ break;
+ }
+ case LUA_MULTRET: {
+ int i;
+ for (i = 0; i < nres; i++) /* move all results to correct place */
+ setobjs2s(L, res + i, firstResult + i);
+ L->top = res + nres;
+ return 0; /* wanted == LUA_MULTRET */
+ }
+ default: {
+ int i;
+ if (wanted <= nres) { /* enough results? */
+ for (i = 0; i < wanted; i++) /* move wanted results to correct place */
+ setobjs2s(L, res + i, firstResult + i);
+ }
+ else { /* not enough results; use all of them plus nils */
+ for (i = 0; i < nres; i++) /* move all results to correct place */
+ setobjs2s(L, res + i, firstResult + i);
+ for (; i < wanted; i++) /* complete wanted number of results */
+ setnilvalue(res + i);
+ }
+ break;
+ }
+ }
+ L->top = res + wanted; /* top points after the last result */
+ return 1;
+}
+
+
+/*
+** Finishes a function call: calls hook if necessary, removes CallInfo,
+** moves current number of results to proper place; returns 0 iff call
+** wanted multiple (variable number of) results.
+*/
+int luaD_poscall (lua_State *L, CallInfo *ci, StkId firstResult, int nres) {
+ StkId res;
+ int wanted = ci->nresults;
+ if (L->hookmask & (LUA_MASKRET | LUA_MASKLINE)) {
+ if (L->hookmask & LUA_MASKRET) {
+ ptrdiff_t fr = savestack(L, firstResult); /* hook may change stack */
+ luaD_hook(L, LUA_HOOKRET, -1);
+ firstResult = restorestack(L, fr);
+ }
+ L->oldpc = ci->previous->u.l.savedpc; /* 'oldpc' for caller function */
+ }
+ res = ci->func; /* res == final position of 1st result */
+ L->ci = ci->previous; /* back to caller */
+ /* move results to proper place */
+ return moveresults(L, firstResult, res, nres, wanted);
+}
+
+
+
+#define next_ci(L) (L->ci = (L->ci->next ? L->ci->next : luaE_extendCI(L)))
+
+
+/* macro to check stack size, preserving 'p' */
+#define checkstackp(L,n,p) \
+ luaD_checkstackaux(L, n, \
+ ptrdiff_t t__ = savestack(L, p); /* save 'p' */ \
+ luaC_checkGC(L), /* stack grow uses memory */ \
+ p = restorestack(L, t__)) /* 'pos' part: restore 'p' */
+
+
+/*
+** Prepares a function call: checks the stack, creates a new CallInfo
+** entry, fills in the relevant information, calls hook if needed.
+** If function is a C function, does the call, too. (Otherwise, leave
+** the execution ('luaV_execute') to the caller, to allow stackless
+** calls.) Returns true iff function has been executed (C function).
+*/
+int luaD_precall (lua_State *L, StkId func, int nresults) {
+ lua_CFunction f;
+ CallInfo *ci;
+ switch (ttype(func)) {
+ case LUA_TCCL: /* C closure */
+ f = clCvalue(func)->f;
+ goto Cfunc;
+ case LUA_TLCF: /* light C function */
+ f = fvalue(func);
+ Cfunc: {
+ int n; /* number of returns */
+ checkstackp(L, LUA_MINSTACK, func); /* ensure minimum stack size */
+ ci = next_ci(L); /* now 'enter' new function */
+ ci->nresults = nresults;
+ ci->func = func;
+ ci->top = L->top + LUA_MINSTACK;
+ lua_assert(ci->top <= L->stack_last);
+ ci->callstatus = 0;
+ if (L->hookmask & LUA_MASKCALL)
+ luaD_hook(L, LUA_HOOKCALL, -1);
+ lua_unlock(L);
+ n = (*f)(L); /* do the actual call */
+ lua_lock(L);
+ api_checknelems(L, n);
+ luaD_poscall(L, ci, L->top - n, n);
+ return 1;
+ }
+ case LUA_TLCL: { /* Lua function: prepare its call */
+ StkId base;
+ Proto *p = clLvalue(func)->p;
+ int n = cast_int(L->top - func) - 1; /* number of real arguments */
+ int fsize = p->maxstacksize; /* frame size */
+ checkstackp(L, fsize, func);
+ if (p->is_vararg)
+ base = adjust_varargs(L, p, n);
+ else { /* non vararg function */
+ for (; n < p->numparams; n++)
+ setnilvalue(L->top++); /* complete missing arguments */
+ base = func + 1;
+ }
+ ci = next_ci(L); /* now 'enter' new function */
+ ci->nresults = nresults;
+ ci->func = func;
+ ci->u.l.base = base;
+ L->top = ci->top = base + fsize;
+ lua_assert(ci->top <= L->stack_last);
+ ci->u.l.savedpc = p->code; /* starting point */
+ ci->callstatus = CIST_LUA;
+ if (L->hookmask & LUA_MASKCALL)
+ callhook(L, ci);
+ return 0;
+ }
+ default: { /* not a function */
+ checkstackp(L, 1, func); /* ensure space for metamethod */
+ tryfuncTM(L, func); /* try to get '__call' metamethod */
+ return luaD_precall(L, func, nresults); /* now it must be a function */
+ }
+ }
+}
+
+
+/*
+** Check appropriate error for stack overflow ("regular" overflow or
+** overflow while handling stack overflow). If 'nCalls' is larger than
+** LUAI_MAXCCALLS (which means it is handling a "regular" overflow) but
+** smaller than 9/8 of LUAI_MAXCCALLS, does not report an error (to
+** allow overflow handling to work)
+*/
+static void stackerror (lua_State *L) {
+ if (L->nCcalls == LUAI_MAXCCALLS)
+ luaG_runerror(L, "C stack overflow");
+ else if (L->nCcalls >= (LUAI_MAXCCALLS + (LUAI_MAXCCALLS>>3)))
+ luaD_throw(L, LUA_ERRERR); /* error while handing stack error */
+}
+
+
+/*
+** Call a function (C or Lua). The function to be called is at *func.
+** The arguments are on the stack, right after the function.
+** When returns, all the results are on the stack, starting at the original
+** function position.
+*/
+void luaD_call (lua_State *L, StkId func, int nResults) {
+ if (++L->nCcalls >= LUAI_MAXCCALLS)
+ stackerror(L);
+ if (!luaD_precall(L, func, nResults)) /* is a Lua function? */
+ luaV_execute(L); /* call it */
+ L->nCcalls--;
+}
+
+
+/*
+** Similar to 'luaD_call', but does not allow yields during the call
+*/
+void luaD_callnoyield (lua_State *L, StkId func, int nResults) {
+ L->nny++;
+ luaD_call(L, func, nResults);
+ L->nny--;
+}
+
+
+/*
+** Completes the execution of an interrupted C function, calling its
+** continuation function.
+*/
+static void finishCcall (lua_State *L, int status) {
+ CallInfo *ci = L->ci;
+ int n;
+ /* must have a continuation and must be able to call it */
+ lua_assert(ci->u.c.k != NULL && L->nny == 0);
+ /* error status can only happen in a protected call */
+ lua_assert((ci->callstatus & CIST_YPCALL) || status == LUA_YIELD);
+ if (ci->callstatus & CIST_YPCALL) { /* was inside a pcall? */
+ ci->callstatus &= ~CIST_YPCALL; /* continuation is also inside it */
+ L->errfunc = ci->u.c.old_errfunc; /* with the same error function */
+ }
+ /* finish 'lua_callk'/'lua_pcall'; CIST_YPCALL and 'errfunc' already
+ handled */
+ adjustresults(L, ci->nresults);
+ lua_unlock(L);
+ n = (*ci->u.c.k)(L, status, ci->u.c.ctx); /* call continuation function */
+ lua_lock(L);
+ api_checknelems(L, n);
+ luaD_poscall(L, ci, L->top - n, n); /* finish 'luaD_precall' */
+}
+
+
+/*
+** Executes "full continuation" (everything in the stack) of a
+** previously interrupted coroutine until the stack is empty (or another
+** interruption long-jumps out of the loop). If the coroutine is
+** recovering from an error, 'ud' points to the error status, which must
+** be passed to the first continuation function (otherwise the default
+** status is LUA_YIELD).
+*/
+static void unroll (lua_State *L, void *ud) {
+ if (ud != NULL) /* error status? */
+ finishCcall(L, *(int *)ud); /* finish 'lua_pcallk' callee */
+ while (L->ci != &L->base_ci) { /* something in the stack */
+ if (!isLua(L->ci)) /* C function? */
+ finishCcall(L, LUA_YIELD); /* complete its execution */
+ else { /* Lua function */
+ luaV_finishOp(L); /* finish interrupted instruction */
+ luaV_execute(L); /* execute down to higher C 'boundary' */
+ }
+ }
+}
+
+
+/*
+** Try to find a suspended protected call (a "recover point") for the
+** given thread.
+*/
+static CallInfo *findpcall (lua_State *L) {
+ CallInfo *ci;
+ for (ci = L->ci; ci != NULL; ci = ci->previous) { /* search for a pcall */
+ if (ci->callstatus & CIST_YPCALL)
+ return ci;
+ }
+ return NULL; /* no pending pcall */
+}
+
+
+/*
+** Recovers from an error in a coroutine. Finds a recover point (if
+** there is one) and completes the execution of the interrupted
+** 'luaD_pcall'. If there is no recover point, returns zero.
+*/
+static int recover (lua_State *L, int status) {
+ StkId oldtop;
+ CallInfo *ci = findpcall(L);
+ if (ci == NULL) return 0; /* no recovery point */
+ /* "finish" luaD_pcall */
+ oldtop = restorestack(L, ci->extra);
+ luaF_close(L, oldtop);
+ seterrorobj(L, status, oldtop);
+ L->ci = ci;
+ L->allowhook = getoah(ci->callstatus); /* restore original 'allowhook' */
+ L->nny = 0; /* should be zero to be yieldable */
+ luaD_shrinkstack(L);
+ L->errfunc = ci->u.c.old_errfunc;
+ return 1; /* continue running the coroutine */
+}
+
+
+/*
+** Signal an error in the call to 'lua_resume', not in the execution
+** of the coroutine itself. (Such errors should not be handled by any
+** coroutine error handler and should not kill the coroutine.)
+*/
+static int resume_error (lua_State *L, const char *msg, int narg) {
+ L->top -= narg; /* remove args from the stack */
+ setsvalue2s(L, L->top, luaS_new(L, msg)); /* push error message */
+ api_incr_top(L);
+ lua_unlock(L);
+ return LUA_ERRRUN;
+}
+
+
+/*
+** Do the work for 'lua_resume' in protected mode. Most of the work
+** depends on the status of the coroutine: initial state, suspended
+** inside a hook, or regularly suspended (optionally with a continuation
+** function), plus erroneous cases: non-suspended coroutine or dead
+** coroutine.
+*/
+static void resume (lua_State *L, void *ud) {
+ int n = *(cast(int*, ud)); /* number of arguments */
+ StkId firstArg = L->top - n; /* first argument */
+ CallInfo *ci = L->ci;
+ if (L->status == LUA_OK) { /* starting a coroutine? */
+ if (!luaD_precall(L, firstArg - 1, LUA_MULTRET)) /* Lua function? */
+ luaV_execute(L); /* call it */
+ }
+ else { /* resuming from previous yield */
+ lua_assert(L->status == LUA_YIELD);
+ L->status = LUA_OK; /* mark that it is running (again) */
+ ci->func = restorestack(L, ci->extra);
+ if (isLua(ci)) /* yielded inside a hook? */
+ luaV_execute(L); /* just continue running Lua code */
+ else { /* 'common' yield */
+ if (ci->u.c.k != NULL) { /* does it have a continuation function? */
+ lua_unlock(L);
+ n = (*ci->u.c.k)(L, LUA_YIELD, ci->u.c.ctx); /* call continuation */
+ lua_lock(L);
+ api_checknelems(L, n);
+ firstArg = L->top - n; /* yield results come from continuation */
+ }
+ luaD_poscall(L, ci, firstArg, n); /* finish 'luaD_precall' */
+ }
+ unroll(L, NULL); /* run continuation */
+ }
+}
+
+
+LUA_API int lua_resume (lua_State *L, lua_State *from, int nargs) {
+ int status;
+ unsigned short oldnny = L->nny; /* save "number of non-yieldable" calls */
+ lua_lock(L);
+ if (L->status == LUA_OK) { /* may be starting a coroutine */
+ if (L->ci != &L->base_ci) /* not in base level? */
+ return resume_error(L, "cannot resume non-suspended coroutine", nargs);
+ }
+ else if (L->status != LUA_YIELD)
+ return resume_error(L, "cannot resume dead coroutine", nargs);
+ L->nCcalls = (from) ? from->nCcalls + 1 : 1;
+ if (L->nCcalls >= LUAI_MAXCCALLS)
+ return resume_error(L, "C stack overflow", nargs);
+ luai_userstateresume(L, nargs);
+ L->nny = 0; /* allow yields */
+ api_checknelems(L, (L->status == LUA_OK) ? nargs + 1 : nargs);
+ status = luaD_rawrunprotected(L, resume, &nargs);
+ if (status == -1) /* error calling 'lua_resume'? */
+ status = LUA_ERRRUN;
+ else { /* continue running after recoverable errors */
+ while (errorstatus(status) && recover(L, status)) {
+ /* unroll continuation */
+ status = luaD_rawrunprotected(L, unroll, &status);
+ }
+ if (errorstatus(status)) { /* unrecoverable error? */
+ L->status = cast_byte(status); /* mark thread as 'dead' */
+ seterrorobj(L, status, L->top); /* push error message */
+ L->ci->top = L->top;
+ }
+ else lua_assert(status == L->status); /* normal end or yield */
+ }
+ L->nny = oldnny; /* restore 'nny' */
+ L->nCcalls--;
+ lua_assert(L->nCcalls == ((from) ? from->nCcalls : 0));
+ lua_unlock(L);
+ return status;
+}
+
+
+LUA_API int lua_isyieldable (lua_State *L) {
+ return (L->nny == 0);
+}
+
+
+LUA_API int lua_yieldk (lua_State *L, int nresults, lua_KContext ctx,
+ lua_KFunction k) {
+ CallInfo *ci = L->ci;
+ luai_userstateyield(L, nresults);
+ lua_lock(L);
+ api_checknelems(L, nresults);
+ if (L->nny > 0) {
+ if (L != G(L)->mainthread)
+ luaG_runerror(L, "attempt to yield across a C-call boundary");
+ else
+ luaG_runerror(L, "attempt to yield from outside a coroutine");
+ }
+ L->status = LUA_YIELD;
+ ci->extra = savestack(L, ci->func); /* save current 'func' */
+ if (isLua(ci)) { /* inside a hook? */
+ api_check(L, k == NULL, "hooks cannot continue after yielding");
+ }
+ else {
+ if ((ci->u.c.k = k) != NULL) /* is there a continuation? */
+ ci->u.c.ctx = ctx; /* save context */
+ ci->func = L->top - nresults - 1; /* protect stack below results */
+ luaD_throw(L, LUA_YIELD);
+ }
+ lua_assert(ci->callstatus & CIST_HOOKED); /* must be inside a hook */
+ lua_unlock(L);
+ return 0; /* return to 'luaD_hook' */
+}
+
+
+int luaD_pcall (lua_State *L, Pfunc func, void *u,
+ ptrdiff_t old_top, ptrdiff_t ef) {
+ int status;
+ CallInfo *old_ci = L->ci;
+ lu_byte old_allowhooks = L->allowhook;
+ unsigned short old_nny = L->nny;
+ ptrdiff_t old_errfunc = L->errfunc;
+ L->errfunc = ef;
+ status = luaD_rawrunprotected(L, func, u);
+ if (status != LUA_OK) { /* an error occurred? */
+ StkId oldtop = restorestack(L, old_top);
+ luaF_close(L, oldtop); /* close possible pending closures */
+ seterrorobj(L, status, oldtop);
+ L->ci = old_ci;
+ L->allowhook = old_allowhooks;
+ L->nny = old_nny;
+ luaD_shrinkstack(L);
+ }
+ L->errfunc = old_errfunc;
+ return status;
+}
+
+
+
+/*
+** Execute a protected parser.
+*/
+struct SParser { /* data to 'f_parser' */
+ ZIO *z;
+ Mbuffer buff; /* dynamic structure used by the scanner */
+ Dyndata dyd; /* dynamic structures used by the parser */
+ const char *mode;
+ const char *name;
+};
+
+
+static void checkmode (lua_State *L, const char *mode, const char *x) {
+ if (mode && strchr(mode, x[0]) == NULL) {
+ luaO_pushfstring(L,
+ "attempt to load a %s chunk (mode is '%s')", x, mode);
+ luaD_throw(L, LUA_ERRSYNTAX);
+ }
+}
+
+
+static void f_parser (lua_State *L, void *ud) {
+ LClosure *cl;
+ struct SParser *p = cast(struct SParser *, ud);
+ int c = zgetc(p->z); /* read first character */
+ if (c == LUA_SIGNATURE[0]) {
+ checkmode(L, p->mode, "binary");
+ cl = luaU_undump(L, p->z, p->name);
+ }
+ else {
+ checkmode(L, p->mode, "text");
+ cl = luaY_parser(L, p->z, &p->buff, &p->dyd, p->name, c);
+ }
+ lua_assert(cl->nupvalues == cl->p->sizeupvalues);
+ luaF_initupvals(L, cl);
+}
+
+
+int luaD_protectedparser (lua_State *L, ZIO *z, const char *name,
+ const char *mode) {
+ struct SParser p;
+ int status;
+ L->nny++; /* cannot yield during parsing */
+ p.z = z; p.name = name; p.mode = mode;
+ p.dyd.actvar.arr = NULL; p.dyd.actvar.size = 0;
+ p.dyd.gt.arr = NULL; p.dyd.gt.size = 0;
+ p.dyd.label.arr = NULL; p.dyd.label.size = 0;
+ luaZ_initbuffer(L, &p.buff);
+ status = luaD_pcall(L, f_parser, &p, savestack(L, L->top), L->errfunc);
+ luaZ_freebuffer(L, &p.buff);
+ luaM_freearray(L, p.dyd.actvar.arr, p.dyd.actvar.size);
+ luaM_freearray(L, p.dyd.gt.arr, p.dyd.gt.size);
+ luaM_freearray(L, p.dyd.label.arr, p.dyd.label.size);
+ L->nny--;
+ return status;
+}
+
+