/*

** $Id: ldblib.c $

** Interface from Lua to its debug API

** See Copyright Notice in lua.h

*/

#define ldblib_c

#define LUA_LIB

#include "lprefix.h"

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include "lua.h"

#include "lauxlib.h"

#include "lualib.h"

#include "llimits.h"

/*

** The hook table at registry[HOOKKEY] maps threads to their current

** hook function.

*/

static const char *const HOOKKEY = "_HOOKKEY";

/*

** If L1 != L, L1 can be in any state, and therefore there are no

** guarantees about its stack space; any push in L1 must be

** checked.

*/

static void checkstack (lua_State *L, lua_State *L1, int n) {

  if (l_unlikely(L != L1 && !lua_checkstack(L1, n)))

    luaL_error(L, "stack overflow");

}

static int db_getregistry (lua_State *L) {

  lua_pushvalue(L, LUA_REGISTRYINDEX);

  return 1;

}

static int db_getmetatable (lua_State *L) {

  luaL_checkany(L, 1);

  if (!lua_getmetatable(L, 1)) {

    lua_pushnil(L);  /* no metatable */

  }

  return 1;

}

static int db_setmetatable (lua_State *L) {

  int t = lua_type(L, 2);

  luaL_argexpected(L, t == LUA_TNIL || t == LUA_TTABLE, 2, "nil or table");

  lua_settop(L, 2);

  lua_setmetatable(L, 1);

  return 1;  /* return 1st argument */

}

static int db_getuservalue (lua_State *L) {

  int n = (int)luaL_optinteger(L, 2, 1);

  if (lua_type(L, 1) != LUA_TUSERDATA)

    luaL_pushfail(L);

  else if (lua_getiuservalue(L, 1, n) != LUA_TNONE) {

    lua_pushboolean(L, 1);

    return 2;

  }

  return 1;

}

static int db_setuservalue (lua_State *L) {

  int n = (int)luaL_optinteger(L, 3, 1);

  luaL_checktype(L, 1, LUA_TUSERDATA);

  luaL_checkany(L, 2);

  lua_settop(L, 2);

  if (!lua_setiuservalue(L, 1, n))

    luaL_pushfail(L);

  return 1;

}

/*

** Auxiliary function used by several library functions: check for

** an optional thread as function's first argument and set 'arg' with

** 1 if this argument is present (so that functions can skip it to

** access their other arguments)

*/

static lua_State *getthread (lua_State *L, int *arg) {

  if (lua_isthread(L, 1)) {

    *arg = 1;

    return lua_tothread(L, 1);

  }

  else {

    *arg = 0;

    return L;  /* function will operate over current thread */

  }

}

/*

** Variations of 'lua_settable', used by 'db_getinfo' to put results

** from 'lua_getinfo' into result table. Key is always a string;

** value can be a string, an int, or a boolean.

*/

static void settabss (lua_State *L, const char *k, const char *v) {

  lua_pushstring(L, v);

  lua_setfield(L, -2, k);

}

static void settabsi (lua_State *L, const char *k, int v) {

  lua_pushinteger(L, v);

  lua_setfield(L, -2, k);

}

static void settabsb (lua_State *L, const char *k, int v) {

  lua_pushboolean(L, v);

  lua_setfield(L, -2, k);

}

/*

** In function 'db_getinfo', the call to 'lua_getinfo' may push

** results on the stack; later it creates the result table to put

** these objects. Function 'treatstackoption' puts the result from

** 'lua_getinfo' on top of the result table so that it can call

** 'lua_setfield'.

*/

static void treatstackoption (lua_State *L, lua_State *L1, const char *fname) {

  if (L == L1)

    lua_rotate(L, -2, 1);  /* exchange object and table */

  else

    lua_xmove(L1, L, 1);  /* move object to the "main" stack */

  lua_setfield(L, -2, fname);  /* put object into table */

}

/*

** Calls 'lua_getinfo' and collects all results in a new table.

** L1 needs stack space for an optional input (function) plus

** two optional outputs (function and line table) from function

** 'lua_getinfo'.

*/

static int db_getinfo (lua_State *L) {

  lua_Debug ar;

  int arg;

  lua_State *L1 = getthread(L, &arg);

  const char *options = luaL_optstring(L, arg+2, "flnSrtu");

  checkstack(L, L1, 3);

  luaL_argcheck(L, options[0] != '>', arg + 2, "invalid option '>'");

  if (lua_isfunction(L, arg + 1)) {  /* info about a function? */

    options = lua_pushfstring(L, ">%s", options);  /* add '>' to 'options' */

    lua_pushvalue(L, arg + 1);  /* move function to 'L1' stack */

    lua_xmove(L, L1, 1);

  }

  else {  /* stack level */

    if (!lua_getstack(L1, (int)luaL_checkinteger(L, arg + 1), &ar)) {

      luaL_pushfail(L);  /* level out of range */

      return 1;

    }

  }

  if (!lua_getinfo(L1, options, &ar))

    return luaL_argerror(L, arg+2, "invalid option");

  lua_newtable(L);  /* table to collect results */

  if (strchr(options, 'S')) {

    lua_pushlstring(L, ar.source, ar.srclen);

    lua_setfield(L, -2, "source");

    settabss(L, "short_src", ar.short_src);

    settabsi(L, "linedefined", ar.linedefined);

    settabsi(L, "lastlinedefined", ar.lastlinedefined);

    settabss(L, "what", ar.what);

  }

  if (strchr(options, 'l'))

    settabsi(L, "currentline", ar.currentline);

  if (strchr(options, 'u')) {

    settabsi(L, "nups", ar.nups);

    settabsi(L, "nparams", ar.nparams);

    settabsb(L, "isvararg", ar.isvararg);

  }

  if (strchr(options, 'n')) {

    settabss(L, "name", ar.name);

    settabss(L, "namewhat", ar.namewhat);

  }

  if (strchr(options, 'r')) {

    settabsi(L, "ftransfer", ar.ftransfer);

    settabsi(L, "ntransfer", ar.ntransfer);

  }

  if (strchr(options, 't')) {

    settabsb(L, "istailcall", ar.istailcall);

    settabsi(L, "extraargs", ar.extraargs);

  }

  if (strchr(options, 'L'))

    treatstackoption(L, L1, "activelines");

  if (strchr(options, 'f'))

    treatstackoption(L, L1, "func");

  return 1;  /* return table */

}

static int db_getlocal (lua_State *L) {

  int arg;

  lua_State *L1 = getthread(L, &arg);

  int nvar = (int)luaL_checkinteger(L, arg + 2);  /* local-variable index */

  if (lua_isfunction(L, arg + 1)) {  /* function argument? */

    lua_pushvalue(L, arg + 1);  /* push function */

    lua_pushstring(L, lua_getlocal(L, NULL, nvar));  /* push local name */

    return 1;  /* return only name (there is no value) */

  }

  else {  /* stack-level argument */

    lua_Debug ar;

    const char *name;

    int level = (int)luaL_checkinteger(L, arg + 1);

    if (l_unlikely(!lua_getstack(L1, level, &ar)))  /* out of range? */

      return luaL_argerror(L, arg+1, "level out of range");

    checkstack(L, L1, 1);

    name = lua_getlocal(L1, &ar, nvar);

    if (name) {

      lua_xmove(L1, L, 1);  /* move local value */

      lua_pushstring(L, name);  /* push name */

      lua_rotate(L, -2, 1);  /* re-order */

      return 2;

    }

    else {

      luaL_pushfail(L);  /* no name (nor value) */

      return 1;

    }

  }

}

static int db_setlocal (lua_State *L) {

  int arg;

  const char *name;

  lua_State *L1 = getthread(L, &arg);

  lua_Debug ar;

  int level = (int)luaL_checkinteger(L, arg + 1);

  int nvar = (int)luaL_checkinteger(L, arg + 2);

  if (l_unlikely(!lua_getstack(L1, level, &ar)))  /* out of range? */

    return luaL_argerror(L, arg+1, "level out of range");

  luaL_checkany(L, arg+3);

  lua_settop(L, arg+3);

  checkstack(L, L1, 1);

  lua_xmove(L, L1, 1);

  name = lua_setlocal(L1, &ar, nvar);

  if (name == NULL)

    lua_pop(L1, 1);  /* pop value (if not popped by 'lua_setlocal') */

  lua_pushstring(L, name);

  return 1;

}

/*

** get (if 'get' is true) or set an upvalue from a closure

*/

static int auxupvalue (lua_State *L, int get) {

  const char *name;

  int n = (int)luaL_checkinteger(L, 2);  /* upvalue index */

  luaL_checktype(L, 1, LUA_TFUNCTION);  /* closure */

  name = get ? lua_getupvalue(L, 1, n) : lua_setupvalue(L, 1, n);

  if (name == NULL) return 0;

  lua_pushstring(L, name);

  lua_insert(L, -(get+1));  /* no-op if get is false */

  return get + 1;

}

static int db_getupvalue (lua_State *L) {

  return auxupvalue(L, 1);

}

static int db_setupvalue (lua_State *L) {

  luaL_checkany(L, 3);

  return auxupvalue(L, 0);

}

/*

** Check whether a given upvalue from a given closure exists and

** returns its index

*/

static void *checkupval (lua_State *L, int argf, int argnup, int *pnup) {

  void *id;

  int nup = (int)luaL_checkinteger(L, argnup);  /* upvalue index */

  luaL_checktype(L, argf, LUA_TFUNCTION);  /* closure */

  id = lua_upvalueid(L, argf, nup);

  if (pnup) {

    luaL_argcheck(L, id != NULL, argnup, "invalid upvalue index");

    *pnup = nup;

  }

  return id;

}

static int db_upvalueid (lua_State *L) {

  void *id = checkupval(L, 1, 2, NULL);

  if (id != NULL)

    lua_pushlightuserdata(L, id);

  else

    luaL_pushfail(L);

  return 1;

}

static int db_upvaluejoin (lua_State *L) {

  int n1, n2;

  checkupval(L, 1, 2, &n1);

  checkupval(L, 3, 4, &n2);

  luaL_argcheck(L, !lua_iscfunction(L, 1), 1, "Lua function expected");

  luaL_argcheck(L, !lua_iscfunction(L, 3), 3, "Lua function expected");

  lua_upvaluejoin(L, 1, n1, 3, n2);

  return 0;

}

/*

** Call hook function registered at hook table for the current

** thread (if there is one)

*/

static void hookf (lua_State *L, lua_Debug *ar) {

  static const char *const hooknames[] =

    {"call", "return", "line", "count", "tail call"};

  lua_getfield(L, LUA_REGISTRYINDEX, HOOKKEY);

  lua_pushthread(L);

  if (lua_rawget(L, -2) == LUA_TFUNCTION) {  /* is there a hook function? */

    lua_pushstring(L, hooknames[(int)ar->event]);  /* push event name */

    if (ar->currentline >= 0)

      lua_pushinteger(L, ar->currentline);  /* push current line */

    else lua_pushnil(L);

    lua_assert(lua_getinfo(L, "lS", ar));

    lua_call(L, 2, 0);  /* call hook function */

  }

}

/*

** Convert a string mask (for 'sethook') into a bit mask

*/

static int makemask (const char *smask, int count) {

  int mask = 0;

  if (strchr(smask, 'c')) mask |= LUA_MASKCALL;

  if (strchr(smask, 'r')) mask |= LUA_MASKRET;

  if (strchr(smask, 'l')) mask |= LUA_MASKLINE;

  if (count > 0) mask |= LUA_MASKCOUNT;

  return mask;

}

/*

** Convert a bit mask (for 'gethook') into a string mask

*/

static char *unmakemask (int mask, char *smask) {

  int i = 0;

  if (mask & LUA_MASKCALL) smask[i++] = 'c';

  if (mask & LUA_MASKRET) smask[i++] = 'r';

  if (mask & LUA_MASKLINE) smask[i++] = 'l';

  smask[i] = '\0';

  return smask;

}

static int db_sethook (lua_State *L) {

  int arg, mask, count;

  lua_Hook func;

  lua_State *L1 = getthread(L, &arg);

  if (lua_isnoneornil(L, arg+1)) {  /* no hook? */

    lua_settop(L, arg+1);

    func = NULL; mask = 0; count = 0;  /* turn off hooks */

  }

  else {

    const char *smask = luaL_checkstring(L, arg+2);

    luaL_checktype(L, arg+1, LUA_TFUNCTION);

    count = (int)luaL_optinteger(L, arg + 3, 0);

    func = hookf; mask = makemask(smask, count);

  }

  if (!luaL_getsubtable(L, LUA_REGISTRYINDEX, HOOKKEY)) {

    /* table just created; initialize it */

    lua_pushliteral(L, "k");

    lua_setfield(L, -2, "__mode");  /** hooktable.__mode = "k" */

    lua_pushvalue(L, -1);

    lua_setmetatable(L, -2);  /* metatable(hooktable) = hooktable */

  }

  checkstack(L, L1, 1);

  lua_pushthread(L1); lua_xmove(L1, L, 1);  /* key (thread) */

  lua_pushvalue(L, arg + 1);  /* value (hook function) */

  lua_rawset(L, -3);  /* hooktable[L1] = new Lua hook */

  lua_sethook(L1, func, mask, count);

  return 0;

}

static int db_gethook (lua_State *L) {

  int arg;

  lua_State *L1 = getthread(L, &arg);

  char buff[5];

  int mask = lua_gethookmask(L1);

  lua_Hook hook = lua_gethook(L1);

  if (hook == NULL) {  /* no hook? */

    luaL_pushfail(L);

    return 1;

  }

  else if (hook != hookf)  /* external hook? */

    lua_pushliteral(L, "external hook");

  else {  /* hook table must exist */

    lua_getfield(L, LUA_REGISTRYINDEX, HOOKKEY);

    checkstack(L, L1, 1);

    lua_pushthread(L1); lua_xmove(L1, L, 1);

    lua_rawget(L, -2);   /* 1st result = hooktable[L1] */

    lua_remove(L, -2);  /* remove hook table */

  }

  lua_pushstring(L, unmakemask(mask, buff));  /* 2nd result = mask */

  lua_pushinteger(L, lua_gethookcount(L1));  /* 3rd result = count */

  return 3;

}

static int db_debug (lua_State *L) {

  for (;;) {

    char buffer[250];

    lua_writestringerror("%s", "lua_debug> ");

    if (fgets(buffer, sizeof(buffer), stdin) == NULL ||

        strcmp(buffer, "cont\n") == 0)

      return 0;

    if (luaL_loadbuffer(L, buffer, strlen(buffer), "=(debug command)") ||

        lua_pcall(L, 0, 0, 0))

      lua_writestringerror("%s\n", luaL_tolstring(L, -1, NULL));

    lua_settop(L, 0);  /* remove eventual returns */

  }

}

static int db_traceback (lua_State *L) {

  int arg;

  lua_State *L1 = getthread(L, &arg);

  const char *msg = lua_tostring(L, arg + 1);

  if (msg == NULL && !lua_isnoneornil(L, arg + 1))  /* non-string 'msg'? */

    lua_pushvalue(L, arg + 1);  /* return it untouched */

  else {

    int level = (int)luaL_optinteger(L, arg + 2, (L == L1) ? 1 : 0);

    luaL_traceback(L, L1, msg, level);

  }

  return 1;

}

static const luaL_Reg dblib[] = {

  {"debug", db_debug},

  {"getuservalue", db_getuservalue},

  {"gethook", db_gethook},

  {"getinfo", db_getinfo},

  {"getlocal", db_getlocal},

  {"getregistry", db_getregistry},

  {"getmetatable", db_getmetatable},

  {"getupvalue", db_getupvalue},

  {"upvaluejoin", db_upvaluejoin},

  {"upvalueid", db_upvalueid},

  {"setuservalue", db_setuservalue},

  {"sethook", db_sethook},

  {"setlocal", db_setlocal},

  {"setmetatable", db_setmetatable},

  {"setupvalue", db_setupvalue},

  {"traceback", db_traceback},

  {NULL, NULL}

};

LUAMOD_API int luaopen_debug (lua_State *L) {

  luaL_newlib(L, dblib);

  return 1;

}