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Generalize file.writelines() to allow iterable objects.

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This commit is contained in:
Tim Peters 2001-09-23 04:06:05 +00:00
parent d31db7e939
commit 2c9aa5ea8d
5 changed files with 92 additions and 36 deletions
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64
Objects/fileobject.c
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@ -1164,55 +1164,54 @@ file_write(PyFileObject *f, PyObject *args)
}
static PyObject *
file_writelines(PyFileObject *f, PyObject *args)
file_writelines(PyFileObject *f, PyObject *seq)
{
#define CHUNKSIZE 1000
PyObject *list, *line;
PyObject *it; /* iter(seq) */
PyObject *result;
int i, j, index, len, nwritten, islist;
assert(seq != NULL);
if (f->f_fp == NULL)
return err_closed();
if (args == NULL || !PySequence_Check(args)) {
PyErr_SetString(PyExc_TypeError,
"writelines() argument must be a sequence of strings");
return NULL;
result = NULL;
list = NULL;
islist = PyList_Check(seq);
if (islist)
it = NULL;
else {
it = PyObject_GetIter(seq);
if (it == NULL) {
PyErr_SetString(PyExc_TypeError,
"writelines() requires an iterable argument");
return NULL;
}
/* From here on, fail by going to error, to reclaim "it". */
list = PyList_New(CHUNKSIZE);
if (list == NULL)
goto error;
}
islist = PyList_Check(args);
/* Strategy: slurp CHUNKSIZE lines into a private list,
checking that they are all strings, then write that list
without holding the interpreter lock, then come back for more. */
index = 0;
if (islist)
list = NULL;
else {
list = PyList_New(CHUNKSIZE);
if (list == NULL)
return NULL;
}
result = NULL;
for (;;) {
for (index = 0; ; index += CHUNKSIZE) {
if (islist) {
Py_XDECREF(list);
list = PyList_GetSlice(args, index, index+CHUNKSIZE);
list = PyList_GetSlice(seq, index, index+CHUNKSIZE);
if (list == NULL)
return NULL;
goto error;
j = PyList_GET_SIZE(list);
}
else {
for (j = 0; j < CHUNKSIZE; j++) {
line = PySequence_GetItem(args, index+j);
line = PyIter_Next(it);
if (line == NULL) {
if (PyErr_ExceptionMatches(
PyExc_IndexError)) {
PyErr_Clear();
break;
}
/* Some other error occurred.
XXX We may lose some output. */
goto error;
if (PyErr_Occurred())
goto error;
break;
}
PyList_SetItem(list, j, line);
}
@ -1271,14 +1270,15 @@ file_writelines(PyFileObject *f, PyObject *args)
if (j < CHUNKSIZE)
break;
index += CHUNKSIZE;
}
Py_INCREF(Py_None);
result = Py_None;
error:
Py_XDECREF(list);
Py_XDECREF(it);
return result;
#undef CHUNKSIZE
}
static char readline_doc[] =
@ -1342,10 +1342,10 @@ static char xreadlines_doc[] =
"often quicker, due to reading ahead internally.";
static char writelines_doc[] =
"writelines(list of strings) -> None. Write the strings to the file.\n"
"writelines(sequence_of_strings) -> None. Write the strings to the file.\n"
"\n"
"Note that newlines are not added. This is equivalent to calling write()\n"
"for each string in the list.";
"Note that newlines are not added. The sequence can be any iterable object\n"
"producing strings. This is equivalent to calling write() for each string.";
static char flush_doc[] =
"flush() -> None. Flush the internal I/O buffer.";