/Modules/gdbmmodule.c
http://unladen-swallow.googlecode.com/ · C · 548 lines · 483 code · 60 blank · 5 comment · 64 complexity · 8ced0d5a433d43052d3ec098a7965f6b MD5 · raw file
- /* DBM module using dictionary interface */
- /* Author: Anthony Baxter, after dbmmodule.c */
- /* Doc strings: Mitch Chapman */
- #include "Python.h"
- #include <sys/types.h>
- #include <sys/stat.h>
- #include <fcntl.h>
- #include "gdbm.h"
- #if defined(WIN32) && !defined(__CYGWIN__)
- #include "gdbmerrno.h"
- extern const char * gdbm_strerror(gdbm_error);
- #endif
- PyDoc_STRVAR(gdbmmodule__doc__,
- "This module provides an interface to the GNU DBM (GDBM) library.\n\
- \n\
- This module is quite similar to the dbm module, but uses GDBM instead to\n\
- provide some additional functionality. Please note that the file formats\n\
- created by GDBM and dbm are incompatible. \n\
- \n\
- GDBM objects behave like mappings (dictionaries), except that keys and\n\
- values are always strings. Printing a GDBM object doesn't print the\n\
- keys and values, and the items() and values() methods are not\n\
- supported.");
- typedef struct {
- PyObject_HEAD
- int di_size; /* -1 means recompute */
- GDBM_FILE di_dbm;
- } dbmobject;
- static PyTypeObject Dbmtype;
- #define is_dbmobject(v) (Py_TYPE(v) == &Dbmtype)
- #define check_dbmobject_open(v) if ((v)->di_dbm == NULL) \
- { PyErr_SetString(DbmError, "GDBM object has already been closed"); \
- return NULL; }
- static PyObject *DbmError;
- PyDoc_STRVAR(gdbm_object__doc__,
- "This object represents a GDBM database.\n\
- GDBM objects behave like mappings (dictionaries), except that keys and\n\
- values are always strings. Printing a GDBM object doesn't print the\n\
- keys and values, and the items() and values() methods are not\n\
- supported.\n\
- \n\
- GDBM objects also support additional operations such as firstkey,\n\
- nextkey, reorganize, and sync.");
- static PyObject *
- newdbmobject(char *file, int flags, int mode)
- {
- dbmobject *dp;
- dp = PyObject_New(dbmobject, &Dbmtype);
- if (dp == NULL)
- return NULL;
- dp->di_size = -1;
- errno = 0;
- if ((dp->di_dbm = gdbm_open(file, 0, flags, mode, NULL)) == 0) {
- if (errno != 0)
- PyErr_SetFromErrno(DbmError);
- else
- PyErr_SetString(DbmError, gdbm_strerror(gdbm_errno));
- Py_DECREF(dp);
- return NULL;
- }
- return (PyObject *)dp;
- }
- /* Methods */
- static void
- dbm_dealloc(register dbmobject *dp)
- {
- if (dp->di_dbm)
- gdbm_close(dp->di_dbm);
- PyObject_Del(dp);
- }
- static Py_ssize_t
- dbm_length(dbmobject *dp)
- {
- if (dp->di_dbm == NULL) {
- PyErr_SetString(DbmError, "GDBM object has already been closed");
- return -1;
- }
- if (dp->di_size < 0) {
- datum key,okey;
- int size;
- okey.dsize=0;
- okey.dptr=NULL;
- size = 0;
- for (key=gdbm_firstkey(dp->di_dbm); key.dptr;
- key = gdbm_nextkey(dp->di_dbm,okey)) {
- size++;
- if(okey.dsize) free(okey.dptr);
- okey=key;
- }
- dp->di_size = size;
- }
- return dp->di_size;
- }
- static PyObject *
- dbm_subscript(dbmobject *dp, register PyObject *key)
- {
- PyObject *v;
- datum drec, krec;
- if (!PyArg_Parse(key, "s#", &krec.dptr, &krec.dsize) )
- return NULL;
- if (dp->di_dbm == NULL) {
- PyErr_SetString(DbmError,
- "GDBM object has already been closed");
- return NULL;
- }
- drec = gdbm_fetch(dp->di_dbm, krec);
- if (drec.dptr == 0) {
- PyErr_SetString(PyExc_KeyError,
- PyString_AS_STRING((PyStringObject *)key));
- return NULL;
- }
- v = PyString_FromStringAndSize(drec.dptr, drec.dsize);
- free(drec.dptr);
- return v;
- }
- static int
- dbm_ass_sub(dbmobject *dp, PyObject *v, PyObject *w)
- {
- datum krec, drec;
- if (!PyArg_Parse(v, "s#", &krec.dptr, &krec.dsize) ) {
- PyErr_SetString(PyExc_TypeError,
- "gdbm mappings have string indices only");
- return -1;
- }
- if (dp->di_dbm == NULL) {
- PyErr_SetString(DbmError,
- "GDBM object has already been closed");
- return -1;
- }
- dp->di_size = -1;
- if (w == NULL) {
- if (gdbm_delete(dp->di_dbm, krec) < 0) {
- PyErr_SetString(PyExc_KeyError,
- PyString_AS_STRING((PyStringObject *)v));
- return -1;
- }
- }
- else {
- if (!PyArg_Parse(w, "s#", &drec.dptr, &drec.dsize)) {
- PyErr_SetString(PyExc_TypeError,
- "gdbm mappings have string elements only");
- return -1;
- }
- errno = 0;
- if (gdbm_store(dp->di_dbm, krec, drec, GDBM_REPLACE) < 0) {
- if (errno != 0)
- PyErr_SetFromErrno(DbmError);
- else
- PyErr_SetString(DbmError,
- gdbm_strerror(gdbm_errno));
- return -1;
- }
- }
- return 0;
- }
- static int
- dbm_contains(register dbmobject *dp, PyObject *arg)
- {
- datum key;
- if ((dp)->di_dbm == NULL) {
- PyErr_SetString(DbmError,
- "GDBM object has already been closed");
- return -1;
- }
- if (!PyString_Check(arg)) {
- PyErr_Format(PyExc_TypeError,
- "gdbm key must be string, not %.100s",
- arg->ob_type->tp_name);
- return -1;
- }
- key.dptr = PyString_AS_STRING(arg);
- key.dsize = PyString_GET_SIZE(arg);
- return gdbm_exists(dp->di_dbm, key);
- }
- static PySequenceMethods dbm_as_sequence = {
- (lenfunc)dbm_length, /*_length*/
- 0, /*sq_concat*/
- 0, /*sq_repeat*/
- 0, /*sq_item*/
- 0, /*sq_slice*/
- 0, /*sq_ass_item*/
- 0, /*sq_ass_slice*/
- (objobjproc)dbm_contains, /*sq_contains*/
- 0, /*sq_inplace_concat*/
- 0 /*sq_inplace_repeat*/
- };
- static PyMappingMethods dbm_as_mapping = {
- (lenfunc)dbm_length, /*mp_length*/
- (binaryfunc)dbm_subscript, /*mp_subscript*/
- (objobjargproc)dbm_ass_sub, /*mp_ass_subscript*/
- };
- PyDoc_STRVAR(dbm_close__doc__,
- "close() -> None\n\
- Closes the database.");
- static PyObject *
- dbm_close(register dbmobject *dp, PyObject *unused)
- {
- if (dp->di_dbm)
- gdbm_close(dp->di_dbm);
- dp->di_dbm = NULL;
- Py_INCREF(Py_None);
- return Py_None;
- }
- PyDoc_STRVAR(dbm_keys__doc__,
- "keys() -> list_of_keys\n\
- Get a list of all keys in the database.");
- static PyObject *
- dbm_keys(register dbmobject *dp, PyObject *unused)
- {
- register PyObject *v, *item;
- datum key, nextkey;
- int err;
- if (dp == NULL || !is_dbmobject(dp)) {
- PyErr_BadInternalCall();
- return NULL;
- }
- check_dbmobject_open(dp);
- v = PyList_New(0);
- if (v == NULL)
- return NULL;
- key = gdbm_firstkey(dp->di_dbm);
- while (key.dptr) {
- item = PyString_FromStringAndSize(key.dptr, key.dsize);
- if (item == NULL) {
- free(key.dptr);
- Py_DECREF(v);
- return NULL;
- }
- err = PyList_Append(v, item);
- Py_DECREF(item);
- if (err != 0) {
- free(key.dptr);
- Py_DECREF(v);
- return NULL;
- }
- nextkey = gdbm_nextkey(dp->di_dbm, key);
- free(key.dptr);
- key = nextkey;
- }
- return v;
- }
- PyDoc_STRVAR(dbm_has_key__doc__,
- "has_key(key) -> boolean\n\
- Find out whether or not the database contains a given key.");
- static PyObject *
- dbm_has_key(register dbmobject *dp, PyObject *args)
- {
- datum key;
- if (!PyArg_ParseTuple(args, "s#:has_key", &key.dptr, &key.dsize))
- return NULL;
- check_dbmobject_open(dp);
- return PyInt_FromLong((long) gdbm_exists(dp->di_dbm, key));
- }
- PyDoc_STRVAR(dbm_firstkey__doc__,
- "firstkey() -> key\n\
- It's possible to loop over every key in the database using this method\n\
- and the nextkey() method. The traversal is ordered by GDBM's internal\n\
- hash values, and won't be sorted by the key values. This method\n\
- returns the starting key.");
- static PyObject *
- dbm_firstkey(register dbmobject *dp, PyObject *unused)
- {
- register PyObject *v;
- datum key;
- check_dbmobject_open(dp);
- key = gdbm_firstkey(dp->di_dbm);
- if (key.dptr) {
- v = PyString_FromStringAndSize(key.dptr, key.dsize);
- free(key.dptr);
- return v;
- }
- else {
- Py_INCREF(Py_None);
- return Py_None;
- }
- }
- PyDoc_STRVAR(dbm_nextkey__doc__,
- "nextkey(key) -> next_key\n\
- Returns the key that follows key in the traversal.\n\
- The following code prints every key in the database db, without having\n\
- to create a list in memory that contains them all:\n\
- \n\
- k = db.firstkey()\n\
- while k != None:\n\
- print k\n\
- k = db.nextkey(k)");
- static PyObject *
- dbm_nextkey(register dbmobject *dp, PyObject *args)
- {
- register PyObject *v;
- datum key, nextkey;
- if (!PyArg_ParseTuple(args, "s#:nextkey", &key.dptr, &key.dsize))
- return NULL;
- check_dbmobject_open(dp);
- nextkey = gdbm_nextkey(dp->di_dbm, key);
- if (nextkey.dptr) {
- v = PyString_FromStringAndSize(nextkey.dptr, nextkey.dsize);
- free(nextkey.dptr);
- return v;
- }
- else {
- Py_INCREF(Py_None);
- return Py_None;
- }
- }
- PyDoc_STRVAR(dbm_reorganize__doc__,
- "reorganize() -> None\n\
- If you have carried out a lot of deletions and would like to shrink\n\
- the space used by the GDBM file, this routine will reorganize the\n\
- database. GDBM will not shorten the length of a database file except\n\
- by using this reorganization; otherwise, deleted file space will be\n\
- kept and reused as new (key,value) pairs are added.");
- static PyObject *
- dbm_reorganize(register dbmobject *dp, PyObject *unused)
- {
- check_dbmobject_open(dp);
- errno = 0;
- if (gdbm_reorganize(dp->di_dbm) < 0) {
- if (errno != 0)
- PyErr_SetFromErrno(DbmError);
- else
- PyErr_SetString(DbmError, gdbm_strerror(gdbm_errno));
- return NULL;
- }
- Py_INCREF(Py_None);
- return Py_None;
- }
- PyDoc_STRVAR(dbm_sync__doc__,
- "sync() -> None\n\
- When the database has been opened in fast mode, this method forces\n\
- any unwritten data to be written to the disk.");
- static PyObject *
- dbm_sync(register dbmobject *dp, PyObject *unused)
- {
- check_dbmobject_open(dp);
- gdbm_sync(dp->di_dbm);
- Py_INCREF(Py_None);
- return Py_None;
- }
- static PyMethodDef dbm_methods[] = {
- {"close", (PyCFunction)dbm_close, METH_NOARGS, dbm_close__doc__},
- {"keys", (PyCFunction)dbm_keys, METH_NOARGS, dbm_keys__doc__},
- {"has_key", (PyCFunction)dbm_has_key, METH_VARARGS, dbm_has_key__doc__},
- {"firstkey", (PyCFunction)dbm_firstkey,METH_NOARGS, dbm_firstkey__doc__},
- {"nextkey", (PyCFunction)dbm_nextkey, METH_VARARGS, dbm_nextkey__doc__},
- {"reorganize",(PyCFunction)dbm_reorganize,METH_NOARGS, dbm_reorganize__doc__},
- {"sync", (PyCFunction)dbm_sync, METH_NOARGS, dbm_sync__doc__},
- {NULL, NULL} /* sentinel */
- };
- static PyObject *
- dbm_getattr(dbmobject *dp, char *name)
- {
- return Py_FindMethod(dbm_methods, (PyObject *)dp, name);
- }
- static PyTypeObject Dbmtype = {
- PyVarObject_HEAD_INIT(0, 0)
- "gdbm.gdbm",
- sizeof(dbmobject),
- 0,
- (destructor)dbm_dealloc, /*tp_dealloc*/
- 0, /*tp_print*/
- (getattrfunc)dbm_getattr, /*tp_getattr*/
- 0, /*tp_setattr*/
- 0, /*tp_compare*/
- 0, /*tp_repr*/
- 0, /*tp_as_number*/
- &dbm_as_sequence, /*tp_as_sequence*/
- &dbm_as_mapping, /*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, /*tp_xxx4*/
- gdbm_object__doc__, /*tp_doc*/
- };
- /* ----------------------------------------------------------------- */
- PyDoc_STRVAR(dbmopen__doc__,
- "open(filename, [flags, [mode]]) -> dbm_object\n\
- Open a dbm database and return a dbm object. The filename argument is\n\
- the name of the database file.\n\
- \n\
- The optional flags argument can be 'r' (to open an existing database\n\
- for reading only -- default), 'w' (to open an existing database for\n\
- reading and writing), 'c' (which creates the database if it doesn't\n\
- exist), or 'n' (which always creates a new empty database).\n\
- \n\
- Some versions of gdbm support additional flags which must be\n\
- appended to one of the flags described above. The module constant\n\
- 'open_flags' is a string of valid additional flags. The 'f' flag\n\
- opens the database in fast mode; altered data will not automatically\n\
- be written to the disk after every change. This results in faster\n\
- writes to the database, but may result in an inconsistent database\n\
- if the program crashes while the database is still open. Use the\n\
- sync() method to force any unwritten data to be written to the disk.\n\
- The 's' flag causes all database operations to be synchronized to\n\
- disk. The 'u' flag disables locking of the database file.\n\
- \n\
- The optional mode argument is the Unix mode of the file, used only\n\
- when the database has to be created. It defaults to octal 0666. ");
- static PyObject *
- dbmopen(PyObject *self, PyObject *args)
- {
- char *name;
- char *flags = "r";
- int iflags;
- int mode = 0666;
- if (!PyArg_ParseTuple(args, "s|si:open", &name, &flags, &mode))
- return NULL;
- switch (flags[0]) {
- case 'r':
- iflags = GDBM_READER;
- break;
- case 'w':
- iflags = GDBM_WRITER;
- break;
- case 'c':
- iflags = GDBM_WRCREAT;
- break;
- case 'n':
- iflags = GDBM_NEWDB;
- break;
- default:
- PyErr_SetString(DbmError,
- "First flag must be one of 'r', 'w', 'c' or 'n'");
- return NULL;
- }
- for (flags++; *flags != '\0'; flags++) {
- char buf[40];
- switch (*flags) {
- #ifdef GDBM_FAST
- case 'f':
- iflags |= GDBM_FAST;
- break;
- #endif
- #ifdef GDBM_SYNC
- case 's':
- iflags |= GDBM_SYNC;
- break;
- #endif
- #ifdef GDBM_NOLOCK
- case 'u':
- iflags |= GDBM_NOLOCK;
- break;
- #endif
- default:
- PyOS_snprintf(buf, sizeof(buf), "Flag '%c' is not supported.",
- *flags);
- PyErr_SetString(DbmError, buf);
- return NULL;
- }
- }
- return newdbmobject(name, iflags, mode);
- }
- static char dbmmodule_open_flags[] = "rwcn"
- #ifdef GDBM_FAST
- "f"
- #endif
- #ifdef GDBM_SYNC
- "s"
- #endif
- #ifdef GDBM_NOLOCK
- "u"
- #endif
- ;
- static PyMethodDef dbmmodule_methods[] = {
- { "open", (PyCFunction)dbmopen, METH_VARARGS, dbmopen__doc__},
- { 0, 0 },
- };
- PyMODINIT_FUNC
- initgdbm(void) {
- PyObject *m, *d, *s;
- Dbmtype.ob_type = &PyType_Type;
- m = Py_InitModule4("gdbm", dbmmodule_methods,
- gdbmmodule__doc__, (PyObject *)NULL,
- PYTHON_API_VERSION);
- if (m == NULL)
- return;
- d = PyModule_GetDict(m);
- DbmError = PyErr_NewException("gdbm.error", NULL, NULL);
- if (DbmError != NULL) {
- PyDict_SetItemString(d, "error", DbmError);
- s = PyString_FromString(dbmmodule_open_flags);
- PyDict_SetItemString(d, "open_flags", s);
- Py_DECREF(s);
- }
- }