/*
 osutil.c - native operating system services

 Copyright 2007 Matt Mackall and others

 This software may be used and distributed according to the terms of
 the GNU General Public License, incorporated herein by reference.
*/

#define _ATFILE_SOURCE
#include <Python.h>
#include <alloca.h>
#include <dirent.h>
#include <fcntl.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>

struct listdir_stat {
    PyObject_HEAD
    struct stat st;
};

#define listdir_slot(name) \
    static PyObject *listdir_stat_##name(PyObject *self, void *x) \
    { \
        return PyInt_FromLong(((struct listdir_stat *) self)->st.name); \
    }

listdir_slot(st_dev);
listdir_slot(st_mode);
listdir_slot(st_nlink);
listdir_slot(st_size);
listdir_slot(st_mtime);
listdir_slot(st_ctime);

static struct PyGetSetDef listdir_stat_getsets[] = {
  {"st_dev", listdir_stat_st_dev, 0, 0, 0},
  {"st_mode", listdir_stat_st_mode, 0, 0, 0},
  {"st_nlink", listdir_stat_st_nlink, 0, 0, 0},
  {"st_size", listdir_stat_st_size, 0, 0, 0},
  {"st_mtime", listdir_stat_st_mtime, 0, 0, 0},
  {"st_ctime", listdir_stat_st_ctime, 0, 0, 0},
  {0, 0, 0, 0, 0}
};

static PyObject *listdir_stat_new(PyTypeObject *t, PyObject *a, PyObject *k)
{
    return (*t->tp_alloc)(t, 0);
}

static void listdir_stat_dealloc(PyObject *o)
{
    (*o->ob_type->tp_free)(o);
}

static PyTypeObject listdir_stat_type = {
    PyObject_HEAD_INIT(NULL)
    0,                         /*ob_size*/
    "osutil.stat",             /*tp_name*/
    sizeof(struct listdir_stat), /*tp_basicsize*/
    0,                         /*tp_itemsize*/
    (destructor)listdir_stat_dealloc, /*tp_dealloc*/
    0,                         /*tp_print*/
    0,                         /*tp_getattr*/
    0,                         /*tp_setattr*/
    0,                         /*tp_compare*/
    0,                         /*tp_repr*/
    0,                         /*tp_as_number*/
    0,                         /*tp_as_sequence*/
    0,                         /*tp_as_mapping*/
    0,                         /*tp_hash */
    0,                         /*tp_call*/
    0,                         /*tp_str*/
    0,                         /*tp_getattro*/
    0,                         /*tp_setattro*/
    0,                         /*tp_as_buffer*/
    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /*tp_flags*/
    "stat objects",           /* tp_doc */
    0,                         /* tp_traverse */
    0,                         /* tp_clear */
    0,                         /* tp_richcompare */
    0,                         /* tp_weaklistoffset */
    0,                         /* tp_iter */
    0,                         /* tp_iternext */
    0,                         /* tp_methods */
    0,                         /* tp_members */
    listdir_stat_getsets,      /* tp_getset */
    0,                         /* tp_base */
    0,                         /* tp_dict */
    0,                         /* tp_descr_get */
    0,                         /* tp_descr_set */
    0,                         /* tp_dictoffset */
    0,                         /* tp_init */
    0,                         /* tp_alloc */
    listdir_stat_new,          /* tp_new */
};

static inline int mode_to_kind(int mode)
{
    if (S_ISREG(mode)) return S_IFREG;
    if (S_ISDIR(mode)) return S_IFDIR;
    if (S_ISLNK(mode)) return S_IFLNK;
    if (S_ISBLK(mode)) return S_IFBLK;
    if (S_ISCHR(mode)) return S_IFCHR;
    if (S_ISFIFO(mode)) return S_IFIFO;
    if (S_ISSOCK(mode)) return S_IFSOCK;
    return mode;
}

static PyObject *listdir(PyObject *self, PyObject *args, PyObject *kwargs)
{
    DIR *dir = NULL;
    struct dirent *ent;
    PyObject *list = NULL;
    PyObject *ctor_args = NULL;
    int all_kinds = 1;
    char *full_path;
    int path_len;
    int do_stat;
    char *path;
    int ret;

    {
	static char *kwlist[] = { "path", "stat", NULL };
	PyObject *statobj = NULL;

	if (!PyArg_ParseTupleAndKeywords(args, kwargs, "s#|O:listdir", kwlist,
					 &path, &path_len, &statobj))
	    goto bail;

	do_stat = statobj && PyObject_IsTrue(statobj);
    }

    if ((dir = opendir(path)) == NULL) {
	list = PyErr_SetFromErrnoWithFilename(PyExc_OSError, path);
        goto bail;
    }

    if ((list = PyList_New(0)) == NULL)
        goto bail;

    full_path = alloca(path_len + PATH_MAX + 2);
    memcpy(full_path, path, path_len);
    full_path[path_len] = '/';

    while ((ent = readdir(dir))) {
        PyObject *name = NULL;
        PyObject *py_kind = NULL;
        PyObject *val = NULL;
        unsigned char d_type;
        int kind = -1;

        if (strcmp(ent->d_name, ".") == 0 || strcmp(ent->d_name, "..") == 0)
            continue;

#ifdef DT_REG
	if (do_stat)
	    d_type = 0;
	else
	    d_type = ent->d_type;
#else
        d_type = 0;
#endif

        switch (d_type) {
#ifdef DT_REG
        case DT_REG: kind = S_IFREG; break;
        case DT_DIR: kind = S_IFDIR; break;
        case DT_LNK: kind = S_IFLNK; break;
        case DT_BLK: kind = S_IFBLK; break;
        case DT_CHR: kind = S_IFCHR; break;
        case DT_FIFO: kind = S_IFIFO; break;
        case DT_SOCK: kind = S_IFSOCK; break;
#endif
	default:
	    if (all_kinds)
		all_kinds = 0;
	    break;
	}

        name = PyString_FromString(ent->d_name);
	if (kind != -1)
	    py_kind = PyInt_FromLong(kind);
	else {
	    py_kind = Py_None;
	    Py_INCREF(Py_None);
	}

        val = PyTuple_New(do_stat ? 3 : 2);

        if (name == NULL || py_kind == NULL || val == NULL) {
            Py_XDECREF(name);
            Py_XDECREF(py_kind);
            Py_XDECREF(val);

            goto bail;
	}

        PyTuple_SET_ITEM(val, 0, name);
        PyTuple_SET_ITEM(val, 1, py_kind);
	if (do_stat) {
	    PyTuple_SET_ITEM(val, 2, Py_None);
	    Py_INCREF(Py_None);
	}

        PyList_Append(list, val);
        Py_DECREF(val);
    }

    PyList_Sort(list);

    if (do_stat || !all_kinds) {
	ssize_t size = PyList_Size(list);
	ssize_t i;
#ifdef AT_SYMLINK_NOFOLLOW
	int dfd = dirfd(dir);
#endif

	for (i = 0; i < size; i++) {
	    PyObject *elt = PyList_GetItem(list, i);
	    char *name = PyString_AsString(PyTuple_GET_ITEM(elt, 0));
	    PyObject *py_st = NULL;
	    PyObject *py_kind = PyTuple_GET_ITEM(elt, 1);
	    int kind;

	    kind = py_kind == Py_None ? -1 : PyInt_AsLong(py_kind);

	    if (kind != -1 && !do_stat)
		continue;

            strcpy(full_path + path_len + 1, name);

	    if (do_stat) {
		struct listdir_stat *st;

		if (ctor_args == NULL) {
		    ctor_args = PyTuple_New(0);
		    if (ctor_args == NULL)
			goto bail;
		}

		st = (struct listdir_stat *)
		    PyObject_CallObject((PyObject *) &listdir_stat_type,
					ctor_args);
		if (st == NULL)
		    goto bail;
#ifdef AT_SYMLINK_NOFOLLOW
		ret = fstatat(dfd, name, &st->st, AT_SYMLINK_NOFOLLOW);
#else
		ret = lstat(full_path, &st->st);
#endif
		if (ret == -1) {
		    list = PyErr_SetFromErrnoWithFilename(PyExc_OSError,
							  full_path);
		    goto bail;
		}
		if (kind == -1)
		    kind = mode_to_kind(st->st.st_mode);
		py_st = (PyObject *) st;
	    } else {
		struct stat buf;
#ifdef AT_SYMLINK_NOFOLLOW
		ret = fstatat(dfd, ent->d_name, &buf, AT_SYMLINK_NOFOLLOW);
#else
		ret = lstat(full_path, &buf);
#endif
		if (ret == -1) {
		    list = PyErr_SetFromErrnoWithFilename(PyExc_OSError,
							  full_path);
		    goto bail;
		}
		if (kind == -1)
		    kind = mode_to_kind(buf.st_mode);
	    }

	    if (py_kind == Py_None && kind != -1) {
		py_kind = PyInt_FromLong(kind);
		if (py_kind == NULL)
		    goto bail;
		Py_XDECREF(Py_None);
		PyTuple_SET_ITEM(elt, 1, py_kind);
	    }

	    if (do_stat) {
		if (py_st == NULL) {
		    py_st = Py_None;
		    Py_INCREF(Py_None);
		}
		PyTuple_SET_ITEM(elt, 2, py_st);
	    }
        }
    }

    goto done;

bail:
    Py_XDECREF(list);

done:
    Py_XDECREF(ctor_args);
    if (dir)
        closedir(dir);

    return list;
}

static char osutil_doc[] = "Native operating system services.";

static PyMethodDef methods[] = {
    {"listdir", (PyCFunction) listdir, METH_VARARGS | METH_KEYWORDS,
     "list a directory\n"},
    {NULL, NULL}
};

PyMODINIT_FUNC initosutil(void)
{
    if (PyType_Ready(&listdir_stat_type) == -1)
        return;

    Py_InitModule3("osutil", methods, osutil_doc);
}