cpython/Objects/fileobject.c

334 lines
7.5 KiB
C

/* File object implementation (what's left of it -- see io.py) */
#define PY_SSIZE_T_CLEAN
#include "Python.h"
#ifdef HAVE_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_FromFile(FILE *fp, char *name, char *mode, int (*close)(FILE *))
{
PyObject *io, *stream, *nameobj;
io = PyImport_ImportModule("io");
if (io == NULL)
return NULL;
stream = PyObject_CallMethod(io, "open", "is", fileno(fp), mode);
Py_DECREF(io);
if (stream == NULL)
return NULL;
nameobj = PyUnicode_FromString(name);
if (nameobj == NULL)
PyErr_Clear();
else {
if (PyObject_SetAttrString(stream, "name", nameobj) < 0)
PyErr_Clear();
Py_DECREF(nameobj);
}
return stream;
}
PyObject *
PyFile_GetLine(PyObject *f, int n)
{
PyObject *result;
if (f == NULL) {
PyErr_BadInternalCall();
return NULL;
}
{
PyObject *reader;
PyObject *args;
reader = PyObject_GetAttrString(f, "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 && !PyString_Check(result) &&
!PyUnicode_Check(result)) {
Py_DECREF(result);
result = NULL;
PyErr_SetString(PyExc_TypeError,
"object.readline() returned non-string");
}
}
if (n < 0 && result != NULL && PyString_Check(result)) {
char *s = PyString_AS_STRING(result);
Py_ssize_t len = PyString_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)
_PyString_Resize(&result, len-1);
else {
PyObject *v;
v = PyString_FromStringAndSize(s, len-1);
Py_DECREF(result);
result = v;
}
}
}
if (n < 0 && result != NULL && PyUnicode_Check(result)) {
Py_UNICODE *s = PyUnicode_AS_UNICODE(result);
Py_ssize_t len = PyUnicode_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)
PyUnicode_Resize(&result, len-1);
else {
PyObject *v;
v = PyUnicode_FromUnicode(s, 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, *args, *result;
if (f == NULL) {
PyErr_SetString(PyExc_TypeError, "writeobject with NULL file");
return -1;
}
writer = PyObject_GetAttrString(f, "write");
if (writer == NULL)
return -1;
if (flags & Py_PRINT_RAW) {
value = _PyObject_Str(v);
}
else
value = PyObject_ReprStr8(v);
if (value == NULL) {
Py_DECREF(writer);
return -1;
}
args = PyTuple_Pack(1, value);
if (args == NULL) {
Py_DECREF(value);
Py_DECREF(writer);
return -1;
}
result = PyEval_CallObject(writer, args);
Py_DECREF(args);
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 or long integer, its value is returned. If not, the
object's fileno() method is called if it exists; the method must return
an integer or long integer, which is returned as the file descriptor value.
-1 is returned on failure.
*/
int
PyObject_AsFileDescriptor(PyObject *o)
{
int fd;
PyObject *meth;
if (PyInt_Check(o)) {
fd = PyInt_AsLong(o);
}
else if (PyLong_Check(o)) {
fd = PyLong_AsLong(o);
}
else if ((meth = PyObject_GetAttrString(o, "fileno")) != NULL)
{
PyObject *fno = PyEval_CallObject(meth, NULL);
Py_DECREF(meth);
if (fno == NULL)
return -1;
if (PyInt_Check(fno)) {
fd = PyInt_AsLong(fno);
Py_DECREF(fno);
}
else if (PyLong_Check(fno)) {
fd = PyLong_AsLong(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;
}
#ifdef __cplusplus
}
#endif