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 #define bytehex(x) (((x)<0xa)?('0'+(x)):('a'-0xa+(x)))
  29
  30 static PyObject *sha_to_pyhex(const unsigned char *sha)
  31 {
  32         char hexsha[41];
  33         int i;
  34         for (i = 0; i < 20; i++) {
  35                 hexsha[i*2] = bytehex((sha[i] & 0xF0) >> 4);
  36                 hexsha[i*2+1] = bytehex(sha[i] & 0x0F);
  37         }
  38
  39         return PyString_FromStringAndSize(hexsha, 40);
  40 }
  41
  42 static PyObject *py_parse_tree(PyObject *self, PyObject *args)
  43 {
  44         char *text, *start, *end;
  45         int len, namelen;
  46         PyObject *ret, *item, *name;
  47
  48         if (!PyArg_ParseTuple(args, "s#", &text, &len))
  49                 return NULL;
  50
  51         /* TODO: currently this returns a list; if memory usage is a concern,
  52         * consider rewriting as a custom iterator object */
  53         ret = PyList_New(0);
  54
  55         if (ret == NULL) {
  56                 return NULL;
  57         }
  58
  59         start = text;
  60         end = text + len;
  61
  62         while (text < end) {
  63                 long mode;
  64                 mode = strtol(text, &text, 8);
  65
  66                 if (*text != ' ') {
  67                         PyErr_SetString(PyExc_ValueError, "Expected space");
  68                         Py_DECREF(ret);
  69                         return NULL;
  70                 }
  71
  72                 text++;
  73
  74                 namelen = strnlen(text, len - (text - start));
  75
  76                 name = PyString_FromStringAndSize(text, namelen);
  77                 if (name == NULL) {
  78                         Py_DECREF(ret);
  79                         return NULL;
  80                 }
  81
  82                 if (text + namelen + 20 >= end) {
  83                         PyErr_SetString(PyExc_ValueError, "SHA truncated");
  84                         Py_DECREF(ret);
  85                         Py_DECREF(name);
  86                         return NULL;
  87                 }
  88
  89                 item = Py_BuildValue("(NlN)", name, mode,
  90                                                          sha_to_pyhex((unsigned char *)text+namelen+1));
  91                 if (item == NULL) {
  92                         Py_DECREF(ret);
  93                         Py_DECREF(name);
  94                         return NULL;
  95                 }
  96                 if (PyList_Append(ret, item) == -1) {
  97                         Py_DECREF(ret);
  98                         Py_DECREF(item);
  99                         return NULL;
 100                 }
 101                 Py_DECREF(item);
 102
 103                 text += namelen+21;
 104         }
 105
 106         return ret;
 107 }
 108
 109 struct tree_item {
 110         const char *name;
 111         int mode;
 112         PyObject *tuple;
 113 };
 114
 115 int cmp_tree_item(const void *_a, const void *_b)
 116 {
 117         const struct tree_item *a = _a, *b = _b;
 118         const char *remain_a, *remain_b;
 119         int ret, common;
 120         if (strlen(a->name) > strlen(b->name)) {
 121                 common = strlen(b->name);
 122                 remain_a = a->name + common;
 123                 remain_b = (S_ISDIR(b->mode)?"/":"");
 124         } else if (strlen(b->name) > strlen(a->name)) {
 125                 common = strlen(a->name);
 126                 remain_a = (S_ISDIR(a->mode)?"/":"");
 127                 remain_b = b->name + common;
 128         } else { /* strlen(a->name) == strlen(b->name) */
 129                 common = 0;
 130                 remain_a = a->name;
 131                 remain_b = b->name;
 132         }
 133         ret = strncmp(a->name, b->name, common);
 134         if (ret != 0)
 135                 return ret;
 136         return strcmp(remain_a, remain_b);
 137 }
 138
 139 static void free_tree_items(struct tree_item *items, int num) {
 140         int i;
 141         for (i = 0; i < num; i++) {
 142                 Py_DECREF(items[i].tuple);
 143         }
 144         free(items);
 145 }
 146
 147 static PyObject *py_sorted_tree_items(PyObject *self, PyObject *entries)
 148 {
 149         struct tree_item *qsort_entries;
 150         int num, i;
 151         PyObject *ret;
 152         Py_ssize_t pos = 0;
 153         PyObject *key, *value;
 154
 155         if (!PyDict_Check(entries)) {
 156                 PyErr_SetString(PyExc_TypeError, "Argument not a dictionary");
 157                 return NULL;
 158         }
 159
 160         num = PyDict_Size(entries);
 161         qsort_entries = malloc(num * sizeof(struct tree_item));
 162         if (qsort_entries == NULL) {
 163                 PyErr_NoMemory();
 164                 return NULL;
 165         }
 166
 167         i = 0;
 168         while (PyDict_Next(entries, &pos, &key, &value)) {
 169                 PyObject *py_mode, *py_int_mode, *py_sha;
 170
 171                 if (!PyString_Check(key)) {
 172                         PyErr_SetString(PyExc_TypeError, "Name is not a string");
 173                         free_tree_items(qsort_entries, i);
 174                         return NULL;
 175                 }
 176
 177                 if (PyTuple_Size(value) != 2) {
 178                         PyErr_SetString(PyExc_ValueError, "Tuple has invalid size");
 179                         free_tree_items(qsort_entries, i);
 180                         return NULL;
 181                 }
 182
 183                 py_mode = PyTuple_GET_ITEM(value, 0);
 184                 py_int_mode = PyNumber_Int(py_mode);
 185                 if (!py_int_mode) {
 186                         PyErr_SetString(PyExc_TypeError, "Mode is not an integral type");
 187                         free_tree_items(qsort_entries, i);
 188                         return NULL;
 189                 }
 190
 191                 py_sha = PyTuple_GET_ITEM(value, 1);
 192                 if (!PyString_Check(py_sha)) {
 193                         PyErr_SetString(PyExc_TypeError, "SHA is not a string");
 194                         Py_DECREF(py_int_mode);
 195                         free_tree_items(qsort_entries, i);
 196                         return NULL;
 197                 }
 198                 qsort_entries[i].name = PyString_AS_STRING(key);
 199                 qsort_entries[i].mode = PyInt_AS_LONG(py_mode);
 200                 qsort_entries[i].tuple = PyTuple_Pack(3, key, py_int_mode, py_sha);
 201                 Py_DECREF(py_int_mode);
 202                 i++;
 203         }
 204
 205         qsort(qsort_entries, num, sizeof(struct tree_item), cmp_tree_item);
 206
 207         ret = PyList_New(num);
 208         if (ret == NULL) {
 209                 free_tree_items(qsort_entries, i);
 210                 PyErr_NoMemory();
 211                 return NULL;
 212         }
 213
 214         for (i = 0; i < num; i++) {
 215                 PyList_SET_ITEM(ret, i, qsort_entries[i].tuple);
 216         }
 217
 218         free(qsort_entries);
 219
 220         return ret;
 221 }
 222
 223 static PyMethodDef py_objects_methods[] = {
 224         { "parse_tree", (PyCFunction)py_parse_tree, METH_VARARGS, NULL },
 225         { "sorted_tree_items", (PyCFunction)py_sorted_tree_items, METH_O, NULL },
 226         { NULL, NULL, 0, NULL }
 227 };
 228
 229 void init_objects(void)
 230 {
 231         PyObject *m;
 232
 233         m = Py_InitModule3("_objects", py_objects_methods, NULL);
 234         if (m == NULL)
 235                 return;
 236 }