dulwich/_objects.c

   1 /*
   2  * Copyright (C) 2009 Jelmer Vernooij <jelmer@samba.org>
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; version 2
   7  * of the License or (at your option) a later version of the License.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
  17  * MA  02110-1301, USA.
  18  */
  19
  20 #include <Python.h>
  21 #include <stdlib.h>
  22 #include <sys/stat.h>
  23
  24 #if (PY_VERSION_HEX < 0x02050000)
  25 typedef int Py_ssize_t;
  26 #endif
  27
  28 #ifdef __MINGW32_VERSION
  29 size_t strnlen(char *text, size_t maxlen)
  30 {
  31         const char *last = memchr(text, '\0', maxlen);
  32         return last ? (size_t) (last - text) : maxlen;
  33 }
  34 #endif
  35
  36 #define bytehex(x) (((x)<0xa)?('0'+(x)):('a'-0xa+(x)))
  37
  38 static PyObject *sha_to_pyhex(const unsigned char *sha)
  39 {
  40         char hexsha[41];
  41         int i;
  42         for (i = 0; i < 20; i++) {
  43                 hexsha[i*2] = bytehex((sha[i] & 0xF0) >> 4);
  44                 hexsha[i*2+1] = bytehex(sha[i] & 0x0F);
  45         }
  46
  47         return PyString_FromStringAndSize(hexsha, 40);
  48 }
  49
  50 static PyObject *py_parse_tree(PyObject *self, PyObject *args)
  51 {
  52         char *text, *start, *end;
  53         int len, namelen;
  54         PyObject *ret, *item, *name;
  55
  56         if (!PyArg_ParseTuple(args, "s#", &text, &len))
  57                 return NULL;
  58
  59         /* TODO: currently this returns a list; if memory usage is a concern,
  60         * consider rewriting as a custom iterator object */
  61         ret = PyList_New(0);
  62
  63         if (ret == NULL) {
  64                 return NULL;
  65         }
  66
  67         start = text;
  68         end = text + len;
  69
  70         while (text < end) {
  71                 long mode;
  72                 mode = strtol(text, &text, 8);
  73
  74                 if (*text != ' ') {
  75                         PyErr_SetString(PyExc_ValueError, "Expected space");
  76                         Py_DECREF(ret);
  77                         return NULL;
  78                 }
  79
  80                 text++;
  81
  82                 namelen = strnlen(text, len - (text - start));
  83
  84                 name = PyString_FromStringAndSize(text, namelen);
  85                 if (name == NULL) {
  86                         Py_DECREF(ret);
  87                         return NULL;
  88                 }
  89
  90                 if (text + namelen + 20 >= end) {
  91                         PyErr_SetString(PyExc_ValueError, "SHA truncated");
  92                         Py_DECREF(ret);
  93                         Py_DECREF(name);
  94                         return NULL;
  95                 }
  96
  97                 item = Py_BuildValue("(NlN)", name, mode,
  98                                                          sha_to_pyhex((unsigned char *)text+namelen+1));
  99                 if (item == NULL) {
 100                         Py_DECREF(ret);
 101                         Py_DECREF(name);
 102                         return NULL;
 103                 }
 104                 if (PyList_Append(ret, item) == -1) {
 105                         Py_DECREF(ret);
 106                         Py_DECREF(item);
 107                         return NULL;
 108                 }
 109                 Py_DECREF(item);
 110
 111                 text += namelen+21;
 112         }
 113
 114         return ret;
 115 }
 116
 117 struct tree_item {
 118         const char *name;
 119         int mode;
 120         PyObject *tuple;
 121 };
 122
 123 int cmp_tree_item(const void *_a, const void *_b)
 124 {
 125         const struct tree_item *a = _a, *b = _b;
 126         const char *remain_a, *remain_b;
 127         int ret, common;
 128         if (strlen(a->name) > strlen(b->name)) {
 129                 common = strlen(b->name);
 130                 remain_a = a->name + common;
 131                 remain_b = (S_ISDIR(b->mode)?"/":"");
 132         } else if (strlen(b->name) > strlen(a->name)) {
 133                 common = strlen(a->name);
 134                 remain_a = (S_ISDIR(a->mode)?"/":"");
 135                 remain_b = b->name + common;
 136         } else { /* strlen(a->name) == strlen(b->name) */
 137                 common = 0;
 138                 remain_a = a->name;
 139                 remain_b = b->name;
 140         }
 141         ret = strncmp(a->name, b->name, common);
 142         if (ret != 0)
 143                 return ret;
 144         return strcmp(remain_a, remain_b);
 145 }
 146
 147 static void free_tree_items(struct tree_item *items, int num) {
 148         int i;
 149         for (i = 0; i < num; i++) {
 150                 Py_DECREF(items[i].tuple);
 151         }
 152         free(items);
 153 }
 154
 155 static PyObject *py_sorted_tree_items(PyObject *self, PyObject *entries)
 156 {
 157         struct tree_item *qsort_entries;
 158         int num, i;
 159         PyObject *ret;
 160         Py_ssize_t pos = 0;
 161         PyObject *key, *value;
 162
 163         if (!PyDict_Check(entries)) {
 164                 PyErr_SetString(PyExc_TypeError, "Argument not a dictionary");
 165                 return NULL;
 166         }
 167
 168         num = PyDict_Size(entries);
 169         qsort_entries = malloc(num * sizeof(struct tree_item));
 170         if (qsort_entries == NULL) {
 171                 PyErr_NoMemory();
 172                 return NULL;
 173         }
 174
 175         i = 0;
 176         while (PyDict_Next(entries, &pos, &key, &value)) {
 177                 PyObject *py_mode, *py_int_mode, *py_sha;
 178
 179                 if (!PyString_Check(key)) {
 180                         PyErr_SetString(PyExc_TypeError, "Name is not a string");
 181                         free_tree_items(qsort_entries, i);
 182                         return NULL;
 183                 }
 184
 185                 if (PyTuple_Size(value) != 2) {
 186                         PyErr_SetString(PyExc_ValueError, "Tuple has invalid size");
 187                         free_tree_items(qsort_entries, i);
 188                         return NULL;
 189                 }
 190
 191                 py_mode = PyTuple_GET_ITEM(value, 0);
 192                 py_int_mode = PyNumber_Int(py_mode);
 193                 if (!py_int_mode) {
 194                         PyErr_SetString(PyExc_TypeError, "Mode is not an integral type");
 195                         free_tree_items(qsort_entries, i);
 196                         return NULL;
 197                 }
 198
 199                 py_sha = PyTuple_GET_ITEM(value, 1);
 200                 if (!PyString_Check(py_sha)) {
 201                         PyErr_SetString(PyExc_TypeError, "SHA is not a string");
 202                         Py_DECREF(py_int_mode);
 203                         free_tree_items(qsort_entries, i);
 204                         return NULL;
 205                 }
 206                 qsort_entries[i].name = PyString_AS_STRING(key);
 207                 qsort_entries[i].mode = PyInt_AS_LONG(py_mode);
 208                 qsort_entries[i].tuple = PyTuple_Pack(3, key, py_int_mode, py_sha);
 209                 Py_DECREF(py_int_mode);
 210                 i++;
 211         }
 212
 213         qsort(qsort_entries, num, sizeof(struct tree_item), cmp_tree_item);
 214
 215         ret = PyList_New(num);
 216         if (ret == NULL) {
 217                 free_tree_items(qsort_entries, i);
 218                 PyErr_NoMemory();
 219                 return NULL;
 220         }
 221
 222         for (i = 0; i < num; i++) {
 223                 PyList_SET_ITEM(ret, i, qsort_entries[i].tuple);
 224         }
 225
 226         free(qsort_entries);
 227
 228         return ret;
 229 }
 230
 231 static PyMethodDef py_objects_methods[] = {
 232         { "parse_tree", (PyCFunction)py_parse_tree, METH_VARARGS, NULL },
 233         { "sorted_tree_items", (PyCFunction)py_sorted_tree_items, METH_O, NULL },
 234         { NULL, NULL, 0, NULL }
 235 };
 236
 237 void init_objects(void)
 238 {
 239         PyObject *m;
 240
 241         m = Py_InitModule3("_objects", py_objects_methods, NULL);
 242         if (m == NULL)
 243                 return;
 244 }