cpython/Objects/fileobject.c at v3.6.15 · python/cpython · GitHub

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/* File object implementation (what's left of it -- see io.py) */

#define PY_SSIZE_T_CLEAN

#include "Python.h"

#if defined(HAVE_GETC_UNLOCKED) && !defined(_Py_MEMORY_SANITIZER)

/* clang MemorySanitizer doesn't yet understand getc_unlocked. */

#define GETC(f) getc_unlocked(f)

#define FLOCKFILE(f) flockfile(f)

#define FUNLOCKFILE(f) funlockfile(f)

#else

#define GETC(f) getc(f)

#define FLOCKFILE(f)

#define FUNLOCKFILE(f)

#endif

/* Newline flags */

#define NEWLINE_UNKNOWN 0 /* No newline seen, yet */

#define NEWLINE_CR 1 /* \r newline seen */

#define NEWLINE_LF 2 /* \n newline seen */

#define NEWLINE_CRLF 4 /* \r\n newline seen */

#ifdef __cplusplus

extern "C" {

#endif

/* External C interface */

PyObject *

PyFile_FromFd(int fd, const char *name, const char *mode, int buffering, const char *encoding,

const char *errors, const char *newline, int closefd)

{

PyObject *io, *stream;

_Py_IDENTIFIER(open);

io = PyImport_ImportModule("io");

if (io == NULL)

return NULL;

stream = _PyObject_CallMethodId(io, &PyId_open, "isisssi", fd, mode,

buffering, encoding, errors,

newline, closefd);

Py_DECREF(io);

if (stream == NULL)

return NULL;

/* ignore name attribute because the name attribute of _BufferedIOMixin

and TextIOWrapper is read only */

return stream;

}

PyObject *

PyFile_GetLine(PyObject *f, int n)

{

PyObject *result;

if (f == NULL) {

PyErr_BadInternalCall();

return NULL;

}

{

PyObject *reader;

PyObject *args;

_Py_IDENTIFIER(readline);

reader = _PyObject_GetAttrId(f, &PyId_readline);

if (reader == NULL)

return NULL;

if (n <= 0)

args = PyTuple_New(0);

else

args = Py_BuildValue("(i)", n);

if (args == NULL) {

Py_DECREF(reader);

return NULL;

}

result = PyEval_CallObject(reader, args);

Py_DECREF(reader);

Py_DECREF(args);

if (result != NULL && !PyBytes_Check(result) &&

!PyUnicode_Check(result)) {

Py_DECREF(result);

result = NULL;

PyErr_SetString(PyExc_TypeError,

"object.readline() returned non-string");

}

if (n < 0 && result != NULL && PyBytes_Check(result)) {

char *s = PyBytes_AS_STRING(result);

Py_ssize_t len = PyBytes_GET_SIZE(result);

if (len == 0) {

Py_DECREF(result);

result = NULL;

PyErr_SetString(PyExc_EOFError,

"EOF when reading a line");

}

else if (s[len-1] == '\n') {

if (result->ob_refcnt == 1)

_PyBytes_Resize(&result, len-1);

else {

PyObject *v;

v = PyBytes_FromStringAndSize(s, len-1);

Py_DECREF(result);

result = v;

}

if (n < 0 && result != NULL && PyUnicode_Check(result)) {

Py_ssize_t len = PyUnicode_GET_LENGTH(result);

if (len == 0) {

Py_DECREF(result);

result = NULL;

PyErr_SetString(PyExc_EOFError,

"EOF when reading a line");

}

else if (PyUnicode_READ_CHAR(result, len-1) == '\n') {

PyObject *v;

v = PyUnicode_Substring(result, 0, len-1);

Py_DECREF(result);

result = v;

}

return result;

}

/* Interfaces to write objects/strings to file-like objects */

int

PyFile_WriteObject(PyObject *v, PyObject *f, int flags)

{

PyObject *writer, *value, *result;

_Py_IDENTIFIER(write);

if (f == NULL) {

PyErr_SetString(PyExc_TypeError, "writeobject with NULL file");

return -1;

}

writer = _PyObject_GetAttrId(f, &PyId_write);

if (writer == NULL)

return -1;

if (flags & Py_PRINT_RAW) {

value = PyObject_Str(v);

}

else

value = PyObject_Repr(v);

if (value == NULL) {

Py_DECREF(writer);

return -1;

}

result = _PyObject_CallArg1(writer, value);

Py_DECREF(value);

Py_DECREF(writer);

if (result == NULL)

return -1;

Py_DECREF(result);

return 0;

}

int

PyFile_WriteString(const char *s, PyObject *f)

{

if (f == NULL) {

/* Should be caused by a pre-existing error */

if (!PyErr_Occurred())

PyErr_SetString(PyExc_SystemError,

"null file for PyFile_WriteString");

return -1;

}

else if (!PyErr_Occurred()) {

PyObject *v = PyUnicode_FromString(s);

int err;

if (v == NULL)

return -1;

err = PyFile_WriteObject(v, f, Py_PRINT_RAW);

Py_DECREF(v);

return err;

}

else

return -1;

}

/* Try to get a file-descriptor from a Python object. If the object

is an integer, its value is returned. If not, the

object's fileno() method is called if it exists; the method must return

an integer, which is returned as the file descriptor value.

-1 is returned on failure.

int

PyObject_AsFileDescriptor(PyObject *o)

{

int fd;

PyObject *meth;

_Py_IDENTIFIER(fileno);

if (PyLong_Check(o)) {

fd = _PyLong_AsInt(o);

}

else if ((meth = _PyObject_GetAttrId(o, &PyId_fileno)) != NULL)

{

PyObject *fno = PyEval_CallObject(meth, NULL);

Py_DECREF(meth);

if (fno == NULL)

return -1;

if (PyLong_Check(fno)) {

fd = _PyLong_AsInt(fno);

Py_DECREF(fno);

}

else {

PyErr_SetString(PyExc_TypeError,

"fileno() returned a non-integer");

Py_DECREF(fno);

return -1;

}

else {

PyErr_SetString(PyExc_TypeError,

"argument must be an int, or have a fileno() method.");

return -1;

}

if (fd == -1 && PyErr_Occurred())

return -1;

if (fd < 0) {

PyErr_Format(PyExc_ValueError,

"file descriptor cannot be a negative integer (%i)",

fd);

return -1;

}

return fd;

}

** Py_UniversalNewlineFgets is an fgets variation that understands

** all of \r, \n and \r\n conventions.

** The stream should be opened in binary mode.

** If fobj is NULL the routine always does newline conversion, and

** it may peek one char ahead to gobble the second char in \r\n.

** If fobj is non-NULL it must be a PyFileObject. In this case there

** is no readahead but in stead a flag is used to skip a following

** \n on the next read. Also, if the file is open in binary mode

** the whole conversion is skipped. Finally, the routine keeps track of

** the different types of newlines seen.

** Note that we need no error handling: fgets() treats error and eof

** identically.

char *

Py_UniversalNewlineFgets(char *buf, int n, FILE *stream, PyObject *fobj)

{

char *p = buf;

int c;

int newlinetypes = 0;

int skipnextlf = 0;

if (fobj) {

errno = ENXIO; /* What can you do... */

return NULL;

}

FLOCKFILE(stream);

c = 'x'; /* Shut up gcc warning */

while (--n > 0 && (c = GETC(stream)) != EOF ) {

if (skipnextlf ) {

skipnextlf = 0;

if (c == '\n') {

/* Seeing a \n here with skipnextlf true

** means we saw a \r before.

newlinetypes |= NEWLINE_CRLF;

c = GETC(stream);

if (c == EOF) break;

} else {

** Note that c == EOF also brings us here,

** so we're okay if the last char in the file

** is a CR.

newlinetypes |= NEWLINE_CR;

}

if (c == '\r') {

/* A \r is translated into a \n, and we skip

** an adjacent \n, if any. We don't set the

** newlinetypes flag until we've seen the next char.

skipnextlf = 1;

c = '\n';

} else if ( c == '\n') {

newlinetypes |= NEWLINE_LF;

}

*p++ = c;

if (c == '\n') break;

}

/* if ( c == EOF && skipnextlf )

newlinetypes |= NEWLINE_CR; */

FUNLOCKFILE(stream);

*p = '\0';

if ( skipnextlf ) {

/* If we have no file object we cannot save the

** skipnextlf flag. We have to readahead, which

** will cause a pause if we're reading from an

** interactive stream, but that is very unlikely

** unless we're doing something silly like

** exec(open("/dev/tty").read()).

c = GETC(stream);

if ( c != '\n' )

ungetc(c, stream);

}

if (p == buf)

return NULL;

return buf;

}

/* **************************** std printer ****************************

* The stdprinter is used during the boot strapping phase as a preliminary

* file like object for sys.stderr.

typedef struct {

PyObject_HEAD

int fd;

} PyStdPrinter_Object;

static PyObject *

stdprinter_new(PyTypeObject *type, PyObject *args, PyObject *kews)

{

PyStdPrinter_Object *self;

assert(type != NULL && type->tp_alloc != NULL);

self = (PyStdPrinter_Object *) type->tp_alloc(type, 0);

if (self != NULL) {

self->fd = -1;

}

return (PyObject *) self;

}

static int

stdprinter_init(PyObject *self, PyObject *args, PyObject *kwds)

{

PyErr_SetString(PyExc_TypeError,

"cannot create 'stderrprinter' instances");

return -1;

}

PyObject *

PyFile_NewStdPrinter(int fd)

{

PyStdPrinter_Object *self;

if (fd != fileno(stdout) && fd != fileno(stderr)) {

/* not enough infrastructure for PyErr_BadInternalCall() */

return NULL;

}

self = PyObject_New(PyStdPrinter_Object,

&PyStdPrinter_Type);

if (self != NULL) {

self->fd = fd;

}

return (PyObject*)self;

}

static PyObject *

stdprinter_write(PyStdPrinter_Object *self, PyObject *args)

{

PyObject *unicode;

PyObject *bytes = NULL;

char *str;

Py_ssize_t n;

int err;

if (self->fd < 0) {

/* fd might be invalid on Windows

* I can't raise an exception here. It may lead to an

* unlimited recursion in the case stderr is invalid.

Py_RETURN_NONE;

}

if (!PyArg_ParseTuple(args, "U", &unicode))

return NULL;

/* encode Unicode to UTF-8 */

str = PyUnicode_AsUTF8AndSize(unicode, &n);

if (str == NULL) {

PyErr_Clear();

bytes = _PyUnicode_AsUTF8String(unicode, "backslashreplace");

if (bytes == NULL)

return NULL;

if (PyBytes_AsStringAndSize(bytes, &str, &n) < 0) {

Py_DECREF(bytes);

return NULL;

}

n = _Py_write(self->fd, str, n);

/* save errno, it can be modified indirectly by Py_XDECREF() */

err = errno;

Py_XDECREF(bytes);

if (n == -1) {

if (err == EAGAIN) {

PyErr_Clear();

Py_RETURN_NONE;

}

return NULL;

}

return PyLong_FromSsize_t(n);

}

static PyObject *

stdprinter_fileno(PyStdPrinter_Object *self)

{

return PyLong_FromLong((long) self->fd);

}

static PyObject *

stdprinter_repr(PyStdPrinter_Object *self)

{

return PyUnicode_FromFormat("<stdprinter(fd=%d) object at 0x%x>",

self->fd, self);

}

static PyObject *

stdprinter_noop(PyStdPrinter_Object *self)

{

Py_RETURN_NONE;

}

static PyObject *

stdprinter_isatty(PyStdPrinter_Object *self)

{

long res;

if (self->fd < 0) {

Py_RETURN_FALSE;

}

Py_BEGIN_ALLOW_THREADS

res = isatty(self->fd);

Py_END_ALLOW_THREADS

return PyBool_FromLong(res);

}

static PyMethodDef stdprinter_methods[] = {

{"close", (PyCFunction)stdprinter_noop, METH_NOARGS, ""},

{"flush", (PyCFunction)stdprinter_noop, METH_NOARGS, ""},

{"fileno", (PyCFunction)stdprinter_fileno, METH_NOARGS, ""},

{"isatty", (PyCFunction)stdprinter_isatty, METH_NOARGS, ""},

{"write", (PyCFunction)stdprinter_write, METH_VARARGS, ""},

{NULL, NULL} /*sentinel */

};

static PyObject *

get_closed(PyStdPrinter_Object *self, void *closure)

{

Py_INCREF(Py_False);

return Py_False;

}

static PyObject *

get_mode(PyStdPrinter_Object *self, void *closure)

{

return PyUnicode_FromString("w");

}

static PyObject *

get_encoding(PyStdPrinter_Object *self, void *closure)

{

Py_RETURN_NONE;

}

static PyGetSetDef stdprinter_getsetlist[] = {

{"closed", (getter)get_closed, NULL, "True if the file is closed"},

{"encoding", (getter)get_encoding, NULL, "Encoding of the file"},

{"mode", (getter)get_mode, NULL, "String giving the file mode"},

{0},

};

PyTypeObject PyStdPrinter_Type = {

PyVarObject_HEAD_INIT(&PyType_Type, 0)

"stderrprinter", /* tp_name */

sizeof(PyStdPrinter_Object), /* tp_basicsize */

0, /* tp_itemsize */

/* methods */

0, /* tp_dealloc */

0, /* tp_print */

0, /* tp_getattr */

0, /* tp_setattr */

0, /* tp_reserved */

(reprfunc)stdprinter_repr, /* tp_repr */

0, /* tp_as_number */

0, /* tp_as_sequence */

0, /* tp_as_mapping */

0, /* tp_hash */

0, /* tp_call */

0, /* tp_str */

PyObject_GenericGetAttr, /* tp_getattro */

0, /* tp_setattro */

0, /* tp_as_buffer */

Py_TPFLAGS_DEFAULT, /* tp_flags */

0, /* tp_doc */

0, /* tp_traverse */

0, /* tp_clear */

0, /* tp_richcompare */

0, /* tp_weaklistoffset */

0, /* tp_iter */

0, /* tp_iternext */

stdprinter_methods, /* tp_methods */

0, /* tp_members */

stdprinter_getsetlist, /* tp_getset */

0, /* tp_base */

0, /* tp_dict */

0, /* tp_descr_get */

0, /* tp_descr_set */

0, /* tp_dictoffset */

stdprinter_init, /* tp_init */

PyType_GenericAlloc, /* tp_alloc */

stdprinter_new, /* tp_new */

PyObject_Del, /* tp_free */

};

#ifdef __cplusplus

}

#endif

cpython/Objects/fileobject.c at v3.6.15 · python/cpython · GitHub

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