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bpo-27580: Add support of null characters in the csv module. (GH-28808)
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@serhiy-storchaka
serhiy-storchaka committed Oct 9, 2021
1 parent b4903af commit b454e8e
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Showing 3 changed files with 70 additions and 38 deletions.
44 changes: 39 additions & 5 deletions Lib/test/test_csv.py
View file
Expand Up @@ -217,6 +217,17 @@ def test_write_escape(self):
self._write_test(['C\\', '6', '7', 'X"'], 'C\\\\,6,7,"X"""',
escapechar='\\', quoting=csv.QUOTE_MINIMAL)

def test_write_lineterminator(self):
for lineterminator in '\r\n', '\n', '\r', '!@#', '\0':
with self.subTest(lineterminator=lineterminator):
with StringIO() as sio:
writer = csv.writer(sio, lineterminator=lineterminator)
writer.writerow(['a', 'b'])
writer.writerow([1, 2])
self.assertEqual(sio.getvalue(),
f'a,b{lineterminator}'
f'1,2{lineterminator}')

def test_write_iterable(self):
self._write_test(iter(['a', 1, 'p,q']), 'a,1,"p,q"')
self._write_test(iter(['a', 1, None]), 'a,1,')
Expand Down Expand Up @@ -286,14 +297,10 @@ def test_read_oddinputs(self):
self._read_test([''], [[]])
self.assertRaises(csv.Error, self._read_test,
['"ab"c'], None, strict = 1)
# cannot handle null bytes for the moment
self.assertRaises(csv.Error, self._read_test,
['ab\0c'], None, strict = 1)
self._read_test(['"ab"c'], [['abc']], doublequote = 0)

self.assertRaises(csv.Error, self._read_test,
[b'ab\0c'], None)

[b'abc'], None)

def test_read_eol(self):
self._read_test(['a,b'], [['a','b']])
Expand All @@ -313,13 +320,30 @@ def test_read_eof(self):
self.assertRaises(csv.Error, self._read_test,
['^'], [], escapechar='^', strict=True)

def test_read_nul(self):
self._read_test(['\0'], [['\0']])
self._read_test(['a,\0b,c'], [['a', '\0b', 'c']])
self._read_test(['a,b\0,c'], [['a', 'b\0', 'c']])
self._read_test(['a,b\\\0,c'], [['a', 'b\0', 'c']], escapechar='\\')
self._read_test(['a,"\0b",c'], [['a', '\0b', 'c']])

def test_read_delimiter(self):
self._read_test(['a,b,c'], [['a', 'b', 'c']])
self._read_test(['a;b;c'], [['a', 'b', 'c']], delimiter=';')
self._read_test(['a\0b\0c'], [['a', 'b', 'c']], delimiter='\0')

def test_read_escape(self):
self._read_test(['a,\\b,c'], [['a', 'b', 'c']], escapechar='\\')
self._read_test(['a,b\\,c'], [['a', 'b,c']], escapechar='\\')
self._read_test(['a,"b\\,c"'], [['a', 'b,c']], escapechar='\\')
self._read_test(['a,"b,\\c"'], [['a', 'b,c']], escapechar='\\')
self._read_test(['a,"b,c\\""'], [['a', 'b,c"']], escapechar='\\')
self._read_test(['a,"b,c"\\'], [['a', 'b,c\\']], escapechar='\\')
self._read_test(['a,^b,c'], [['a', 'b', 'c']], escapechar='^')
self._read_test(['a,\0b,c'], [['a', 'b', 'c']], escapechar='\0')
self._read_test(['a,\\b,c'], [['a', '\\b', 'c']], escapechar=None)
self._read_test(['a,\\b,c'], [['a', '\\b', 'c']], escapechar='')
self._read_test(['a,\\b,c'], [['a', '\\b', 'c']])

def test_read_quoting(self):
self._read_test(['1,",3,",5'], [['1', ',3,', '5']])
Expand All @@ -334,6 +358,8 @@ def test_read_quoting(self):
self.assertRaises(ValueError, self._read_test,
['abc,3'], [[]],
quoting=csv.QUOTE_NONNUMERIC)
self._read_test(['1,@,3,@,5'], [['1', ',3,', '5']], quotechar='@')
self._read_test(['1,\0,3,\0,5'], [['1', ',3,', '5']], quotechar='\0')

def test_read_bigfield(self):
# This exercises the buffer realloc functionality and field size
Expand Down Expand Up @@ -1074,6 +1100,12 @@ class TestSniffer(unittest.TestCase):
a,b
""")

sample14 = """\
abc\0def
ghijkl\0mno
ghi\0jkl
"""

def test_issue43625(self):
sniffer = csv.Sniffer()
self.assertTrue(sniffer.has_header(self.sample12))
Expand Down Expand Up @@ -1142,6 +1174,8 @@ def test_delimiters(self):
dialect = sniffer.sniff(self.sample9)
self.assertEqual(dialect.delimiter, '+')
self.assertEqual(dialect.quotechar, "'")
dialect = sniffer.sniff(self.sample14)
self.assertEqual(dialect.delimiter, '\0')

def test_doublequote(self):
sniffer = csv.Sniffer()
Expand Down
1 change: 1 addition & 0 deletions Misc/NEWS.d/next/Library/2021-10-07-21-11-48.bpo-27580.tGcBTH.rst
View file
@@ -0,0 +1 @@
Add support of null characters in :mod:`csv`.
63 changes: 30 additions & 33 deletions Modules/_csv.c
View file
Expand Up @@ -14,6 +14,9 @@ module instead.
#include "structmember.h" // PyMemberDef
#include <stdbool.h>

#define NOT_SET ((Py_UCS4)-1)
#define EOL ((Py_UCS4)-2)


typedef struct {
PyObject *error_obj; /* CSV exception */
Expand Down Expand Up @@ -153,9 +156,9 @@ get_dialect_from_registry(PyObject *name_obj, _csvstate *module_state)
}

static PyObject *
get_nullchar_as_None(Py_UCS4 c)
get_char_or_None(Py_UCS4 c)
{
if (c == '\0') {
if (c == NOT_SET) {
Py_RETURN_NONE;
}
else
Expand All @@ -172,19 +175,19 @@ Dialect_get_lineterminator(DialectObj *self, void *Py_UNUSED(ignored))
static PyObject *
Dialect_get_delimiter(DialectObj *self, void *Py_UNUSED(ignored))
{
return get_nullchar_as_None(self->delimiter);
return get_char_or_None(self->delimiter);
}

static PyObject *
Dialect_get_escapechar(DialectObj *self, void *Py_UNUSED(ignored))
{
return get_nullchar_as_None(self->escapechar);
return get_char_or_None(self->escapechar);
}

static PyObject *
Dialect_get_quotechar(DialectObj *self, void *Py_UNUSED(ignored))
{
return get_nullchar_as_None(self->quotechar);
return get_char_or_None(self->quotechar);
}

static PyObject *
Expand Down Expand Up @@ -235,7 +238,7 @@ _set_char_or_none(const char *name, Py_UCS4 *target, PyObject *src, Py_UCS4 dflt
*target = dflt;
}
else {
*target = '\0';
*target = NOT_SET;
if (src != Py_None) {
if (!PyUnicode_Check(src)) {
PyErr_Format(PyExc_TypeError,
Expand All @@ -254,7 +257,7 @@ _set_char_or_none(const char *name, Py_UCS4 *target, PyObject *src, Py_UCS4 dflt
return -1;
}
/* PyUnicode_READY() is called in PyUnicode_GetLength() */
else {
else if (len > 0) {
*target = PyUnicode_READ_CHAR(src, 0);
}
}
Expand All @@ -269,7 +272,7 @@ _set_char(const char *name, Py_UCS4 *target, PyObject *src, Py_UCS4 dflt)
*target = dflt;
}
else {
*target = '\0';
*target = NOT_SET;
if (!PyUnicode_Check(src)) {
PyErr_Format(PyExc_TypeError,
"\"%s\" must be string, not %.200s", name,
Expand All @@ -287,7 +290,7 @@ _set_char(const char *name, Py_UCS4 *target, PyObject *src, Py_UCS4 dflt)
return -1;
}
/* PyUnicode_READY() is called in PyUnicode_GetLength() */
else {
else if (len > 0) {
*target = PyUnicode_READ_CHAR(src, 0);
}
}
Expand Down Expand Up @@ -481,7 +484,7 @@ dialect_new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
goto err
DIASET(_set_char, "delimiter", &self->delimiter, delimiter, ',');
DIASET(_set_bool, "doublequote", &self->doublequote, doublequote, true);
DIASET(_set_char_or_none, "escapechar", &self->escapechar, escapechar, 0);
DIASET(_set_char_or_none, "escapechar", &self->escapechar, escapechar, NOT_SET);
DIASET(_set_str, "lineterminator", &self->lineterminator, lineterminator, "\r\n");
DIASET(_set_char_or_none, "quotechar", &self->quotechar, quotechar, '"');
DIASET(_set_int, "quoting", &self->quoting, quoting, QUOTE_MINIMAL);
Expand All @@ -491,19 +494,19 @@ dialect_new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
/* validate options */
if (dialect_check_quoting(self->quoting))
goto err;
if (self->delimiter == 0) {
if (self->delimiter == NOT_SET) {
PyErr_SetString(PyExc_TypeError,
"\"delimiter\" must be a 1-character string");
goto err;
}
if (quotechar == Py_None && quoting == NULL)
self->quoting = QUOTE_NONE;
if (self->quoting != QUOTE_NONE && self->quotechar == 0) {
if (self->quoting != QUOTE_NONE && self->quotechar == NOT_SET) {
PyErr_SetString(PyExc_TypeError,
"quotechar must be set if quoting enabled");
goto err;
}
if (self->lineterminator == 0) {
if (self->lineterminator == NULL) {
PyErr_SetString(PyExc_TypeError, "lineterminator must be set");
goto err;
}
Expand Down Expand Up @@ -670,7 +673,7 @@ parse_process_char(ReaderObj *self, _csvstate *module_state, Py_UCS4 c)
switch (self->state) {
case START_RECORD:
/* start of record */
if (c == '\0')
if (c == EOL)
/* empty line - return [] */
break;
else if (c == '\n' || c == '\r') {
Expand All @@ -682,11 +685,11 @@ parse_process_char(ReaderObj *self, _csvstate *module_state, Py_UCS4 c)
/* fallthru */
case START_FIELD:
/* expecting field */
if (c == '\n' || c == '\r' || c == '\0') {
if (c == '\n' || c == '\r' || c == EOL) {
/* save empty field - return [fields] */
if (parse_save_field(self) < 0)
return -1;
self->state = (c == '\0' ? START_RECORD : EAT_CRNL);
self->state = (c == EOL ? START_RECORD : EAT_CRNL);
}
else if (c == dialect->quotechar &&
dialect->quoting != QUOTE_NONE) {
Expand Down Expand Up @@ -722,25 +725,25 @@ parse_process_char(ReaderObj *self, _csvstate *module_state, Py_UCS4 c)
self->state = AFTER_ESCAPED_CRNL;
break;
}
if (c == '\0')
if (c == EOL)
c = '\n';
if (parse_add_char(self, module_state, c) < 0)
return -1;
self->state = IN_FIELD;
break;

case AFTER_ESCAPED_CRNL:
if (c == '\0')
if (c == EOL)
break;
/*fallthru*/

case IN_FIELD:
/* in unquoted field */
if (c == '\n' || c == '\r' || c == '\0') {
if (c == '\n' || c == '\r' || c == EOL) {
/* end of line - return [fields] */
if (parse_save_field(self) < 0)
return -1;
self->state = (c == '\0' ? START_RECORD : EAT_CRNL);
self->state = (c == EOL ? START_RECORD : EAT_CRNL);
}
else if (c == dialect->escapechar) {
/* possible escaped character */
Expand All @@ -761,7 +764,7 @@ parse_process_char(ReaderObj *self, _csvstate *module_state, Py_UCS4 c)

case IN_QUOTED_FIELD:
/* in quoted field */
if (c == '\0')
if (c == EOL)
;
else if (c == dialect->escapechar) {
/* Possible escape character */
Expand All @@ -786,7 +789,7 @@ parse_process_char(ReaderObj *self, _csvstate *module_state, Py_UCS4 c)
break;

case ESCAPE_IN_QUOTED_FIELD:
if (c == '\0')
if (c == EOL)
c = '\n';
if (parse_add_char(self, module_state, c) < 0)
return -1;
Expand All @@ -808,11 +811,11 @@ parse_process_char(ReaderObj *self, _csvstate *module_state, Py_UCS4 c)
return -1;
self->state = START_FIELD;
}
else if (c == '\n' || c == '\r' || c == '\0') {
else if (c == '\n' || c == '\r' || c == EOL) {
/* end of line - return [fields] */
if (parse_save_field(self) < 0)
return -1;
self->state = (c == '\0' ? START_RECORD : EAT_CRNL);
self->state = (c == EOL ? START_RECORD : EAT_CRNL);
}
else if (!dialect->strict) {
if (parse_add_char(self, module_state, c) < 0)
Expand All @@ -831,7 +834,7 @@ parse_process_char(ReaderObj *self, _csvstate *module_state, Py_UCS4 c)
case EAT_CRNL:
if (c == '\n' || c == '\r')
;
else if (c == '\0')
else if (c == EOL)
self->state = START_RECORD;
else {
PyErr_Format(module_state->error_obj,
Expand Down Expand Up @@ -909,20 +912,14 @@ Reader_iternext(ReaderObj *self)
linelen = PyUnicode_GET_LENGTH(lineobj);
while (linelen--) {
c = PyUnicode_READ(kind, data, pos);
if (c == '\0') {
Py_DECREF(lineobj);
PyErr_Format(module_state->error_obj,
"line contains NUL");
goto err;
}
if (parse_process_char(self, module_state, c) < 0) {
Py_DECREF(lineobj);
goto err;
}
pos++;
}
Py_DECREF(lineobj);
if (parse_process_char(self, module_state, 0) < 0)
if (parse_process_char(self, module_state, EOL) < 0)
goto err;
} while (self->state != START_RECORD);

Expand Down Expand Up @@ -1127,7 +1124,7 @@ join_append_data(WriterObj *self, unsigned int field_kind, const void *field_dat
*quoted = 1;
}
if (want_escape) {
if (!dialect->escapechar) {
if (dialect->escapechar == NOT_SET) {
PyErr_Format(self->error_obj,
"need to escape, but no escapechar set");
return -1;
Expand Down

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