/*
dirs.c - dynamic directory diddling for dirstates
Copyright 2013 Facebook
This software may be used and distributed according to the terms of
the GNU General Public License, incorporated herein by reference.
*/
#define PY_SSIZE_T_CLEAN
#include <Python.h>
#include "util.h"
/*
* This is a multiset of directory names, built from the files that
* appear in a dirstate or manifest.
*
* A few implementation notes:
*
* We modify Python integers for refcounting, but those integers are
* never visible to Python code.
*
* We mutate strings in-place, but leave them immutable once they can
* be seen by Python code.
*/
typedef struct {
PyObject_HEAD
PyObject *dict;
} dirsObject;
static inline Py_ssize_t _finddir(PyObject *path, Py_ssize_t pos)
{
const char *s = PyString_AS_STRING(path);
while (pos != -1) {
if (s[pos] == '/')
break;
pos -= 1;
}
return pos;
}
static int _addpath(PyObject *dirs, PyObject *path)
{
const char *cpath = PyString_AS_STRING(path);
Py_ssize_t pos = PyString_GET_SIZE(path);
PyObject *key = NULL;
int ret = -1;
while ((pos = _finddir(path, pos - 1)) != -1) {
PyObject *val;
/* It's likely that every prefix already has an entry
in our dict. Try to avoid allocating and
deallocating a string for each prefix we check. */
if (key != NULL)
((PyStringObject *)key)->ob_shash = -1;
else {
/* Force Python to not reuse a small shared string. */
key = PyString_FromStringAndSize(cpath,
pos < 2 ? 2 : pos);
if (key == NULL)
goto bail;
}
PyString_GET_SIZE(key) = pos;
PyString_AS_STRING(key)[pos] = '\0';
val = PyDict_GetItem(dirs, key);
if (val != NULL) {
PyInt_AS_LONG(val) += 1;
continue;
}
/* Force Python to not reuse a small shared int. */
val = PyInt_FromLong(0x1eadbeef);
if (val == NULL)
goto bail;
PyInt_AS_LONG(val) = 1;
ret = PyDict_SetItem(dirs, key, val);
Py_DECREF(val);
if (ret == -1)
goto bail;
Py_CLEAR(key);
}
ret = 0;
bail:
Py_XDECREF(key);
return ret;
}
static int _delpath(PyObject *dirs, PyObject *path)
{
Py_ssize_t pos = PyString_GET_SIZE(path);
PyObject *key = NULL;
int ret = -1;
while ((pos = _finddir(path, pos - 1)) != -1) {
PyObject *val;
key = PyString_FromStringAndSize(PyString_AS_STRING(path), pos);
if (key == NULL)
goto bail;
val = PyDict_GetItem(dirs, key);
if (val == NULL) {
PyErr_SetString(PyExc_ValueError,
"expected a value, found none");
goto bail;
}
if (--PyInt_AS_LONG(val) <= 0 &&
PyDict_DelItem(dirs, key) == -1)
goto bail;
Py_CLEAR(key);
}
ret = 0;
bail:
Py_XDECREF(key);
return ret;
}
static int dirs_fromdict(PyObject *dirs, PyObject *source, char skipchar)
{
PyObject *key, *value;
Py_ssize_t pos = 0;
while (PyDict_Next(source, &pos, &key, &value)) {
if (!PyString_Check(key)) {
PyErr_SetString(PyExc_TypeError, "expected string key");
return -1;
}
if (skipchar) {
PyObject *st;
if (!PyTuple_Check(value) ||
PyTuple_GET_SIZE(value) == 0) {
PyErr_SetString(PyExc_TypeError,
"expected non-empty tuple");
return -1;
}
st = PyTuple_GET_ITEM(value, 0);
if (!PyString_Check(st) || PyString_GET_SIZE(st) == 0) {
PyErr_SetString(PyExc_TypeError,
"expected non-empty string "
"at tuple index 0");
return -1;
}
if (PyString_AS_STRING(st)[0] == skipchar)
continue;
}
if (_addpath(dirs, key) == -1)
return -1;
}
return 0;
}
static int dirs_fromiter(PyObject *dirs, PyObject *source)
{
PyObject *iter, *item = NULL;
int ret;
iter = PyObject_GetIter(source);
if (iter == NULL)
return -1;
while ((item = PyIter_Next(iter)) != NULL) {
if (!PyString_Check(item)) {
PyErr_SetString(PyExc_TypeError, "expected string");
break;
}
if (_addpath(dirs, item) == -1)
break;
Py_CLEAR(item);
}
ret = PyErr_Occurred() ? -1 : 0;
Py_XDECREF(item);
return ret;
}
/*
* Calculate a refcounted set of directory names for the files in a
* dirstate.
*/
static int dirs_init(dirsObject *self, PyObject *args)
{
PyObject *dirs = NULL, *source = NULL;
char skipchar = 0;
int ret = -1;
self->dict = NULL;
if (!PyArg_ParseTuple(args, "|Oc:__init__", &source, &skipchar))
return -1;
dirs = PyDict_New();
if (dirs == NULL)
return -1;
if (source == NULL)
ret = 0;
else if (PyDict_Check(source))
ret = dirs_fromdict(dirs, source, skipchar);
else if (skipchar)
PyErr_SetString(PyExc_ValueError,
"skip character is only supported "
"with a dict source");
else
ret = dirs_fromiter(dirs, source);
if (ret == -1)
Py_XDECREF(dirs);
else
self->dict = dirs;
return ret;
}
PyObject *dirs_addpath(dirsObject *self, PyObject *args)
{
PyObject *path;
if (!PyArg_ParseTuple(args, "O!:addpath", &PyString_Type, &path))
return NULL;
if (_addpath(self->dict, path) == -1)
return NULL;
Py_RETURN_NONE;
}
static PyObject *dirs_delpath(dirsObject *self, PyObject *args)
{
PyObject *path;
if (!PyArg_ParseTuple(args, "O!:delpath", &PyString_Type, &path))
return NULL;
if (_delpath(self->dict, path) == -1)
return NULL;
Py_RETURN_NONE;
}
static int dirs_contains(dirsObject *self, PyObject *value)
{
return PyString_Check(value) ? PyDict_Contains(self->dict, value) : 0;
}
static void dirs_dealloc(dirsObject *self)
{
Py_XDECREF(self->dict);
PyObject_Del(self);
}
static PyObject *dirs_iter(dirsObject *self)
{
return PyObject_GetIter(self->dict);
}
static PySequenceMethods dirs_sequence_methods;
static PyMethodDef dirs_methods[] = {
{"addpath", (PyCFunction)dirs_addpath, METH_VARARGS, "add a path"},
{"delpath", (PyCFunction)dirs_delpath, METH_VARARGS, "remove a path"},
{NULL} /* Sentinel */
};
static PyTypeObject dirsType = { PyObject_HEAD_INIT(NULL) };
void dirs_module_init(PyObject *mod)
{
dirs_sequence_methods.sq_contains = (objobjproc)dirs_contains;
dirsType.tp_name = "parsers.dirs";
dirsType.tp_new = PyType_GenericNew;
dirsType.tp_basicsize = sizeof(dirsObject);
dirsType.tp_dealloc = (destructor)dirs_dealloc;
dirsType.tp_as_sequence = &dirs_sequence_methods;
dirsType.tp_flags = Py_TPFLAGS_DEFAULT;
dirsType.tp_doc = "dirs";
dirsType.tp_iter = (getiterfunc)dirs_iter;
dirsType.tp_methods = dirs_methods;
dirsType.tp_init = (initproc)dirs_init;
if (PyType_Ready(&dirsType) < 0)
return;
Py_INCREF(&dirsType);
PyModule_AddObject(mod, "dirs", (PyObject *)&dirsType);
}