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added lots of new comments + small changes in code

pull/9/head
Roberto Ierusalimschy 11 years ago
parent
15e8405731
commit
6a5d87771f
1 changed files with 94 additions and 61 deletions
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  1. 155
      ldblib.c

155
ldblib.c
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@ -1,5 +1,5 @@
/*
** $Id: ldblib.c,v 1.137 2014/03/12 20:57:40 roberto Exp roberto $
** $Id: ldblib.c,v 1.138 2014/04/30 18:59:15 roberto Exp roberto $
** Interface from Lua to its debug API
** See Copyright Notice in lua.h
*/
@ -28,7 +28,7 @@ static int db_Csize (lua_State *L) {
} sizes[] = {
{'I', sizeof(lua_Integer)},
{'F', sizeof(lua_Number)},
{'b', CHAR_BIT},
{'b', CHAR_BIT}, /* here is number of bits (not bytes) */
{'h', sizeof(short)},
{'i', sizeof(int)},
{'l', sizeof(long)},
@ -91,24 +91,12 @@ static int db_setuservalue (lua_State *L) {
}
static void settabss (lua_State *L, const char *i, const char *v) {
lua_pushstring(L, v);
lua_setfield(L, -2, i);
}
static void settabsi (lua_State *L, const char *i, int v) {
lua_pushinteger(L, v);
lua_setfield(L, -2, i);
}
static void settabsb (lua_State *L, const char *i, int v) {
lua_pushboolean(L, v);
lua_setfield(L, -2, i);
}
/*
** 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;
@ -116,44 +104,70 @@ static lua_State *getthread (lua_State *L, int *arg) {
}
else {
*arg = 0;
return L;
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_pushvalue(L, -2);
lua_remove(L, -3);
}
if (L == L1)
lua_rotate(L, -2, 1); /* exchange object and table */
else
lua_xmove(L1, L, 1);
lua_setfield(L, -2, fname);
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.
*/
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, "flnStu");
if (lua_isnumber(L, arg+1)) {
if (!lua_getstack(L1, (int)lua_tointeger(L, arg+1), &ar)) {
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, luaL_checkint(L, arg + 1), &ar)) {
lua_pushnil(L); /* level out of range */
return 1;
}
}
else if (lua_isfunction(L, arg+1)) {
lua_pushfstring(L, ">%s", options);
options = lua_tostring(L, -1);
lua_pushvalue(L, arg+1);
lua_xmove(L, L1, 1);
}
else
return luaL_argerror(L, arg+1, "function or level expected");
if (!lua_getinfo(L1, options, &ar))
return luaL_argerror(L, arg+2, "invalid option");
lua_createtable(L, 0, 2);
lua_newtable(L); /* table to collect results */
if (strchr(options, 'S')) {
settabss(L, "source", ar.source);
settabss(L, "short_src", ar.short_src);
@ -191,16 +205,16 @@ static int db_getlocal (lua_State *L) {
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 1; /* return only name (there is no value) */
}
else { /* stack-level argument */
if (!lua_getstack(L1, luaL_checkint(L, arg+1), &ar)) /* out of range? */
return luaL_argerror(L, arg+1, "level out of range");
name = lua_getlocal(L1, &ar, nvar);
if (name) {
lua_xmove(L1, L, 1); /* push local value */
lua_xmove(L1, L, 1); /* move local value */
lua_pushstring(L, name); /* push name */
lua_pushvalue(L, -2); /* re-order */
lua_rotate(L, -2, 1); /* re-order */
return 2;
}
else {
@ -225,14 +239,17 @@ static int db_setlocal (lua_State *L) {
}
/*
** 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 = luaL_checkint(L, 2);
luaL_checktype(L, 1, LUA_TFUNCTION);
int n = luaL_checkint(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));
lua_insert(L, -(get+1)); /* no-op if get is false */
return get + 1;
}
@ -248,13 +265,15 @@ static int db_setupvalue (lua_State *L) {
}
/*
** Check whether a given upvalue from a given closure exists and
** returns its index
*/
static int checkupval (lua_State *L, int argf, int argnup) {
lua_Debug ar;
int nup = luaL_checkint(L, argnup);
luaL_checktype(L, argf, LUA_TFUNCTION);
lua_pushvalue(L, argf);
lua_getinfo(L, ">u", &ar);
luaL_argcheck(L, 1 <= nup && nup <= ar.nups, argnup, "invalid upvalue index");
int nup = luaL_checkint(L, argnup); /* upvalue index */
luaL_checktype(L, argf, LUA_TFUNCTION); /* closure */
luaL_argcheck(L, (lua_getupvalue(L, argf, nup) != NULL), argnup,
"invalid upvalue index");
return nup;
}
@ -276,25 +295,36 @@ static int db_upvaluejoin (lua_State *L) {
}
/*
** The hook table (at registry[HOOKKEY]) maps threads to their current
** hook function
*/
#define gethooktable(L) luaL_getsubtable(L, LUA_REGISTRYINDEX, HOOKKEY)
/*
** 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"};
gethooktable(L);
lua_pushthread(L);
if (lua_rawget(L, -2) == LUA_TFUNCTION) {
lua_pushstring(L, hooknames[(int)ar->event]);
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);
lua_pushinteger(L, ar->currentline); /* push current line */
else lua_pushnil(L);
lua_assert(lua_getinfo(L, "lS", ar));
lua_call(L, 2, 0);
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;
@ -305,6 +335,9 @@ static int makemask (const char *smask, int count) {
}
/*
** 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';
@ -319,7 +352,7 @@ 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)) {
if (lua_isnoneornil(L, arg+1)) { /* no hook? */
lua_settop(L, arg+1);
func = NULL; mask = 0; count = 0; /* turn off hooks */
}
@ -335,9 +368,9 @@ static int db_sethook (lua_State *L) {
lua_pushvalue(L, -1);
lua_setmetatable(L, -2); /* setmetatable(hooktable) = hooktable */
}
lua_pushthread(L1); lua_xmove(L1, L, 1);
lua_pushvalue(L, arg+1);
lua_rawset(L, -3); /* set new hook */
lua_pushthread(L1); lua_xmove(L1, L, 1); /* key */
lua_pushvalue(L, arg+1); /* value */
lua_rawset(L, -3); /* hooktable[L1] = new Lua hook */
lua_sethook(L1, func, mask, count); /* set hooks */
return 0;
}
@ -354,11 +387,11 @@ static int db_gethook (lua_State *L) {
else {
gethooktable(L);
lua_pushthread(L1); lua_xmove(L1, L, 1);
lua_rawget(L, -2); /* get hook */
lua_rawget(L, -2); /* 1st result = hooktable[L1] */
lua_remove(L, -2); /* remove hook table */
}
lua_pushstring(L, unmakemask(mask, buff));
lua_pushinteger(L, lua_gethookcount(L1));
lua_pushstring(L, unmakemask(mask, buff)); /* 2nd result = mask */
lua_pushinteger(L, lua_gethookcount(L1)); /* 3rd result = count */
return 3;
}

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