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Issue #12797: Added custom opener parameter to builtin open() and FileIO.open().

This commit is contained in:
Ross Lagerwall 2011-10-31 20:34:46 +02:00
parent ab06e3f285
commit 59142db6d3
7 changed files with 89 additions and 22 deletions
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11
Doc/library/functions.rst
View File

@ -776,7 +776,7 @@ are always available. They are listed here in alphabetical order.
:meth:`__index__` method that returns an integer.
.. function:: open(file, mode='r', buffering=-1, encoding=None, errors=None, newline=None, closefd=True)
.. function:: open(file, mode='r', buffering=-1, encoding=None, errors=None, newline=None, closefd=True, opener=None)
Open *file* and return a corresponding stream. If the file cannot be opened,
an :exc:`OSError` is raised.
@ -883,6 +883,15 @@ are always available. They are listed here in alphabetical order.
closed. If a filename is given *closefd* has no effect and must be ``True``
(the default).
A custom opener can be used by passing a callable as *opener*. The underlying
file descriptor for the file object is then obtained by calling *opener* with
(*file*, *flags*). *opener* must return an open file descriptor (passing
:mod:`os.open` as *opener* results in functionality similar to passing
``None``).
.. versionchanged:: 3.3
The *opener* parameter was added.
The type of file object returned by the :func:`open` function depends on the
mode. When :func:`open` is used to open a file in a text mode (``'w'``,
``'r'``, ``'wt'``, ``'rt'``, etc.), it returns a subclass of

11
Doc/library/io.rst
View File

@ -458,7 +458,7 @@ I/O Base Classes
Raw File I/O
^^^^^^^^^^^^
.. class:: FileIO(name, mode='r', closefd=True)
.. class:: FileIO(name, mode='r', closefd=True, opener=None)
:class:`FileIO` represents an OS-level file containing bytes data.
It implements the :class:`RawIOBase` interface (and therefore the
@ -479,6 +479,15 @@ Raw File I/O
The :meth:`read` (when called with a positive argument), :meth:`readinto`
and :meth:`write` methods on this class will only make one system call.
A custom opener can be used by passing a callable as *opener*. The underlying
file descriptor for the file object is then obtained by calling *opener* with
(*name*, *flags*). *opener* must return an open file descriptor (passing
:mod:`os.open` as *opener* results in functionality similar to passing
``None``).
.. versionchanged:: 3.3
The *opener* parameter was added.
In addition to the attributes and methods from :class:`IOBase` and
:class:`RawIOBase`, :class:`FileIO` provides the following data
attributes and methods:

10
Lib/_pyio.py
View File

@ -27,7 +27,7 @@ BlockingIOError = BlockingIOError
def open(file, mode="r", buffering=-1, encoding=None, errors=None,
newline=None, closefd=True):
newline=None, closefd=True, opener=None):
r"""Open file and return a stream. Raise IOError upon failure.
@ -122,6 +122,12 @@ def open(file, mode="r", buffering=-1, encoding=None, errors=None,
be kept open when the file is closed. This does not work when a file name is
given and must be True in that case.
A custom opener can be used by passing a callable as *opener*. The
underlying file descriptor for the file object is then obtained by calling
*opener* with (*file*, *flags*). *opener* must return an open file
descriptor (passing os.open as *opener* results in functionality similar to
passing None).
open() returns a file object whose type depends on the mode, and
through which the standard file operations such as reading and writing
are performed. When open() is used to open a file in a text mode ('w',
@ -176,7 +182,7 @@ def open(file, mode="r", buffering=-1, encoding=None, errors=None,
(writing and "w" or "") +
(appending and "a" or "") +
(updating and "+" or ""),
closefd)
closefd, opener=opener)
line_buffering = False
if buffering == 1 or buffering < 0 and raw.isatty():
buffering = -1

9
Lib/test/test_io.py
View File

@ -621,6 +621,15 @@ class IOTest(unittest.TestCase):
for obj in test:
self.assertTrue(hasattr(obj, "__dict__"))
def test_opener(self):
with self.open(support.TESTFN, "w") as f:
f.write("egg\n")
fd = os.open(support.TESTFN, os.O_RDONLY)
def opener(path, flags):
return fd
with self.open("non-existent", "r", opener=opener) as f:
self.assertEqual(f.read(), "egg\n")
class CIOTest(IOTest):
def test_IOBase_finalize(self):

3
Misc/NEWS
View File

@ -10,6 +10,9 @@ What's New in Python 3.3 Alpha 1?
Core and Builtins
-----------------
- Issue #12797: Added custom opener parameter to builtin open() and
FileIO.open().
- Issue #10519: Avoid unnecessary recursive function calls in
setobject.c.

18
Modules/_io/_iomodule.c
View File

@ -95,7 +95,7 @@ PyDoc_STRVAR(module_doc,
*/
PyDoc_STRVAR(open_doc,
"open(file, mode='r', buffering=-1, encoding=None,\n"
" errors=None, newline=None, closefd=True) -> file object\n"
" errors=None, newline=None, closefd=True, opener=None) -> file object\n"
"\n"
"Open file and return a stream. Raise IOError upon failure.\n"
"\n"
@ -190,6 +190,12 @@ PyDoc_STRVAR(open_doc,
"when the file is closed. This does not work when a file name is given\n"
"and must be True in that case.\n"
"\n"
"A custom opener can be used by passing a callable as *opener*. The\n"
"underlying file descriptor for the file object is then obtained by\n"
"calling *opener* with (*file*, *flags*). *opener* must return an open\n"
"file descriptor (passing os.open as *opener* results in functionality\n"
"similar to passing None).\n"
"\n"
"open() returns a file object whose type depends on the mode, and\n"
"through which the standard file operations such as reading and writing\n"
"are performed. When open() is used to open a file in a text mode ('w',\n"
@ -210,8 +216,8 @@ io_open(PyObject *self, PyObject *args, PyObject *kwds)
{
char *kwlist[] = {"file", "mode", "buffering",
"encoding", "errors", "newline",
"closefd", NULL};
PyObject *file;
"closefd", "opener", NULL};
PyObject *file, *opener = Py_None;
char *mode = "r";
int buffering = -1, closefd = 1;
char *encoding = NULL, *errors = NULL, *newline = NULL;
@ -228,10 +234,10 @@ io_open(PyObject *self, PyObject *args, PyObject *kwds)
_Py_IDENTIFIER(isatty);
_Py_IDENTIFIER(fileno);
if (!PyArg_ParseTupleAndKeywords(args, kwds, "O|sizzzi:open", kwlist,
if (!PyArg_ParseTupleAndKeywords(args, kwds, "O|sizzziO:open", kwlist,
&file, &mode, &buffering,
&encoding, &errors, &newline,
&closefd)) {
&closefd, &opener)) {
return NULL;
}
@ -331,7 +337,7 @@ io_open(PyObject *self, PyObject *args, PyObject *kwds)
/* Create the Raw file stream */
raw = PyObject_CallFunction((PyObject *)&PyFileIO_Type,
"Osi", file, rawmode, closefd);
"OsiO", file, rawmode, closefd, opener);
if (raw == NULL)
return NULL;

49
Modules/_io/fileio.c
View File

@ -212,9 +212,9 @@ static int
fileio_init(PyObject *oself, PyObject *args, PyObject *kwds)
{
fileio *self = (fileio *) oself;
static char *kwlist[] = {"file", "mode", "closefd", NULL};
static char *kwlist[] = {"file", "mode", "closefd", "opener", NULL};
const char *name = NULL;
PyObject *nameobj, *stringobj = NULL;
PyObject *nameobj, *stringobj = NULL, *opener = Py_None;
char *mode = "r";
char *s;
#ifdef MS_WINDOWS
@ -233,8 +233,9 @@ fileio_init(PyObject *oself, PyObject *args, PyObject *kwds)
return -1;
}
if (!PyArg_ParseTupleAndKeywords(args, kwds, "O|si:fileio",
kwlist, &nameobj, &mode, &closefd))
if (!PyArg_ParseTupleAndKeywords(args, kwds, "O|siO:fileio",
kwlist, &nameobj, &mode, &closefd,
&opener))
return -1;
if (PyFloat_Check(nameobj)) {
@ -363,15 +364,35 @@ fileio_init(PyObject *oself, PyObject *args, PyObject *kwds)
goto error;
}
Py_BEGIN_ALLOW_THREADS
errno = 0;
if (opener == Py_None) {
Py_BEGIN_ALLOW_THREADS
#ifdef MS_WINDOWS
if (widename != NULL)
self->fd = _wopen(widename, flags, 0666);
else
if (widename != NULL)
self->fd = _wopen(widename, flags, 0666);
else
#endif
self->fd = open(name, flags, 0666);
Py_END_ALLOW_THREADS
self->fd = open(name, flags, 0666);
Py_END_ALLOW_THREADS
} else {
PyObject *fdobj = PyObject_CallFunction(
opener, "Oi", nameobj, flags);
if (fdobj == NULL)
goto error;
if (!PyLong_Check(fdobj)) {
Py_DECREF(fdobj);
PyErr_SetString(PyExc_TypeError,
"expected integer from opener");
goto error;
}
self->fd = PyLong_AsLong(fdobj);
Py_DECREF(fdobj);
if (self->fd == -1) {
goto error;
}
}
if (self->fd < 0) {
#ifdef MS_WINDOWS
if (widename != NULL)
@ -1017,13 +1038,17 @@ fileio_getstate(fileio *self)
PyDoc_STRVAR(fileio_doc,
"file(name: str[, mode: str]) -> file IO object\n"
"file(name: str[, mode: str][, opener: None]) -> file IO object\n"
"\n"
"Open a file. The mode can be 'r', 'w' or 'a' for reading (default),\n"
"writing or appending. The file will be created if it doesn't exist\n"
"when opened for writing or appending; it will be truncated when\n"
"opened for writing. Add a '+' to the mode to allow simultaneous\n"
"reading and writing.");
"reading and writing. A custom opener can be used by passing a\n"
"callable as *opener*. The underlying file descriptor for the file\n"
"object is then obtained by calling opener with (*name*, *flags*).\n"
"*opener* must return an open file descriptor (passing os.open as\n"
"*opener* results in functionality similar to passing None).");
PyDoc_STRVAR(read_doc,
"read(size: int) -> bytes. read at most size bytes, returned as bytes.\n"