Create a lua table representing tree of current working dir.

luaTree.c

#include "lua.h"
#include "lualib.h"
#include "lauxlib.h"

#include <dirent.h>
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <sys/stat.h>

#define PATHBUFLEN 1024
#define RECURLIMIT 16
#define TREEFILESLIMIT 1024

#define sdump(L, str) printf("\e[32m"); stackDump(L); printf("\e[0m"); printf((str)); printf(".\n");
static void stackDump (lua_State *L) {
  int i;
  int top = lua_gettop(L);
  for (i = 1; i <= top; i++) { /* repeat for each level */
    int t = lua_type(L, i);
    switch (t) {
    case LUA_TSTRING:  printf("'%s'", lua_tostring(L, i));             break;
    case LUA_TBOOLEAN: printf(lua_toboolean(L, i) ? "true" : "false"); break;
    case LUA_TNUMBER:  printf("%g", lua_tonumber(L, i));               break;
    default:           printf("%s", lua_typename(L, t));               break;
    }
    printf("\t"); /* put a separator */
  }
}

/********************************************************************************/
/********************************************************************************/
/********************************************************************************/

static inline void initTree(lua_State *L, const char *basepath) {
  sdump(L, "init")
    lua_newtable(L);

  lua_pushstring(L, "base");
  lua_pushstring(L, basepath);
  lua_rawset(L, -3);

  lua_pushstring(L, "files");
  lua_newtable(L);
  lua_rawset(L, -3);

  lua_pushstring(L, "dirs");
  lua_newtable(L);
  lua_rawset(L, -3);
  sdump(L, "endinit")
}

static inline void fillTree(lua_State *L, char *pathbuf) {
  DIR *d = opendir(pathbuf);

  if (d) {
    size_t files = 0, dirs = 0, baselen = strlen(pathbuf);
    struct dirent *entry;
    size_t entries = 0; while(entry = readdir(d)) entries++;

    if (entries < TREEFILESLIMIT) {
      rewinddir(d);

      lua_pushstring(L, "dirs"); lua_rawget(L, -2);
      lua_pushstring(L, "files"); lua_rawget(L, -3);

      while ((entry = readdir(d))) {
        char *name = entry-> d_name;

        char c1 = name[0], c2 = name[1];
        if (!(c1 == '.' && (!c2 || (c2 == '.' && !name[2])))) {

          pathbuf[baselen] = '/';
          pathbuf[baselen + 1] = 0;
          strcat(pathbuf, name);

          struct stat s;
          if (lstat(pathbuf, &s) != -1) {
            if (S_ISDIR(s.st_mode)) {
              initTree(L, name);
              fillTree(L, pathbuf);
              lua_rawseti(L, -2, ++dirs);
            } else {
              lua_pushstring(L, name);
              lua_rawseti(L, -3, ++files);
            }
          }

          pathbuf[baselen] = 0;
        }
      }

      lua_pop(L, 2);

      closedir(d);
    }
  }
};

static inline int l_tree(lua_State *L) {
  luaL_checktype(L, 1, LUA_TSTRING); /* 1 subsequence to ssmatch against to. */

  size_t lpath;
  const char *path = luaL_checklstring(L, 1, &lpath);

  char basepath[PATHBUFLEN];

  if (path[lpath - 1] == '/') {
    strncpy(basepath, path, lpath - 1);
  } else {
    strcpy(basepath, path);
  }

  lua_pop(L, 1); // done with the basepath.

  initTree(L, basepath);
  fillTree(L, basepath);

  return 1;
}

static const struct luaL_Reg mwalker [] = {
  {"tree", l_tree},
  {NULL, NULL} /* sentinel */
};

int luaopen_mwalker(lua_State *L) {
  luaL_register(L, "mwalker", mwalker);
  return 1;
}