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Issue #22286: The "backslashreplace" error handlers now works with 

decoding and translating.
This commit is contained in:
Serhiy Storchaka 2015-01-25 22:56:57 +02:00
parent 58f02019e0
commit 07985ef387
10 changed files with 200 additions and 87 deletions
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7
Doc/howto/unicode.rst
View File

@ -280,8 +280,9 @@ and optionally an *errors* argument.
The *errors* argument specifies the response when the input string can't be
converted according to the encoding's rules. Legal values for this argument are
``'strict'`` (raise a :exc:`UnicodeDecodeError` exception), ``'replace'`` (use
``U+FFFD``, ``REPLACEMENT CHARACTER``), or ``'ignore'`` (just leave the
character out of the Unicode result).
``U+FFFD``, ``REPLACEMENT CHARACTER``), ``'ignore'`` (just leave the
character out of the Unicode result), or ``'backslashreplace'`` (inserts a
``\xNN`` escape sequence).
The following examples show the differences::
>>> b'\x80abc'.decode("utf-8", "strict") #doctest: +NORMALIZE_WHITESPACE
@ -291,6 +292,8 @@ The following examples show the differences::
invalid start byte
>>> b'\x80abc'.decode("utf-8", "replace")
'\ufffdabc'
>>> b'\x80abc'.decode("utf-8", "backslashreplace")
'\\x80abc'
>>> b'\x80abc'.decode("utf-8", "ignore")
'abc'

14
Doc/library/codecs.rst
View File

@ -314,8 +314,8 @@ The following error handlers are only applicable to
| | reference (only for encoding). Implemented |
| | in :func:`xmlcharrefreplace_errors`. |
+-------------------------+-----------------------------------------------+
| ``'backslashreplace'`` | Replace with backslashed escape sequences |
| | (only for encoding). Implemented in |
| ``'backslashreplace'`` | Replace with backslashed escape sequences. |
| | Implemented in |
| | :func:`backslashreplace_errors`. |
+-------------------------+-----------------------------------------------+
| ``'namereplace'`` | Replace with ``\N{...}`` escape sequences |
@ -350,6 +350,10 @@ In addition, the following error handler is specific to the given codecs:
.. versionadded:: 3.5
The ``'namereplace'`` error handler.
.. versionchanged:: 3.5
The ``'backslashreplace'`` error handlers now works with decoding and
translating.
The set of allowed values can be extended by registering a new named error
handler:
@ -417,9 +421,9 @@ functions:
.. function:: backslashreplace_errors(exception)
Implements the ``'backslashreplace'`` error handling (for encoding with
:term:`text encodings <text encoding>` only): the
unencodable character is replaced by a backslashed escape sequence.
Implements the ``'backslashreplace'`` error handling (for
:term:`text encodings <text encoding>` only): malformed data is
replaced by a backslashed escape sequence.
.. function:: namereplace_errors(exception)

5
Doc/library/functions.rst
View File

@ -973,9 +973,8 @@ are always available. They are listed here in alphabetical order.
Characters not supported by the encoding are replaced with the
appropriate XML character reference ``&#nnn;``.
* ``'backslashreplace'`` (also only supported when writing)
replaces unsupported characters with Python's backslashed escape
sequences.
* ``'backslashreplace'`` replaces malformed data by Python's backslashed
escape sequences.
* ``'namereplace'`` (also only supported when writing)
replaces unsupported characters with ``\N{...}`` escape sequences.

11
Doc/library/io.rst
View File

@ -825,11 +825,12 @@ Text I/O
exception if there is an encoding error (the default of ``None`` has the same
effect), or pass ``'ignore'`` to ignore errors. (Note that ignoring encoding
errors can lead to data loss.) ``'replace'`` causes a replacement marker
(such as ``'?'``) to be inserted where there is malformed data. When
writing, ``'xmlcharrefreplace'`` (replace with the appropriate XML character
reference), ``'backslashreplace'`` (replace with backslashed escape
sequences) or ``'namereplace'`` (replace with ``\N{...}`` escape sequences)
can be used. Any other error handling name that has been registered with
(such as ``'?'``) to be inserted where there is malformed data.
``'backslashreplace'`` causes malformed data to be replaced by a
backslashed escape sequence. When writing, ``'xmlcharrefreplace'``
(replace with the appropriate XML character reference) or ``'namereplace'``
(replace with ``\N{...}`` escape sequences) can be used. Any other error
handling name that has been registered with
:func:`codecs.register_error` is also valid.
.. index::

4
Doc/whatsnew/3.5.rst
View File

@ -118,7 +118,9 @@ Other Language Changes
Some smaller changes made to the core Python language are:
* None yet.
* Added the ``'namereplace'`` error handlers. The ``'backslashreplace'``
error handlers now works with decoding and translating.
(Contributed by Serhiy Storchaka in :issue:`19676` and :issue:`22286`.)

9
Lib/codecs.py
View File

@ -127,7 +127,8 @@ class Codec:
'surrogateescape' - replace with private code points U+DCnn.
'xmlcharrefreplace' - Replace with the appropriate XML
character reference (only for encoding).
'backslashreplace' - Replace with backslashed escape sequences
'backslashreplace' - Replace with backslashed escape sequences.
'namereplace' - Replace with \\N{...} escape sequences
(only for encoding).
The set of allowed values can be extended via register_error.
@ -359,7 +360,8 @@ class StreamWriter(Codec):
'xmlcharrefreplace' - Replace with the appropriate XML
character reference.
'backslashreplace' - Replace with backslashed escape
sequences (only for encoding).
sequences.
'namereplace' - Replace with \\N{...} escape sequences.
The set of allowed parameter values can be extended via
register_error.
@ -429,7 +431,8 @@ class StreamReader(Codec):
'strict' - raise a ValueError (or a subclass)
'ignore' - ignore the character and continue with the next
'replace'- replace with a suitable replacement character;
'replace'- replace with a suitable replacement character
'backslashreplace' - Replace with backslashed escape sequences;
The set of allowed parameter values can be extended via
register_error.

26
Lib/test/test_codeccallbacks.py
View File

@ -246,6 +246,11 @@ class CodecCallbackTest(unittest.TestCase):
"\u0000\ufffd"
)
self.assertEqual(
b"\x00\x00\x00\x00\x00".decode("unicode-internal", "backslashreplace"),
"\u0000\\x00"
)
codecs.register_error("test.hui", handler_unicodeinternal)
self.assertEqual(
@ -565,17 +570,6 @@ class CodecCallbackTest(unittest.TestCase):
codecs.backslashreplace_errors,
UnicodeError("ouch")
)
# "backslashreplace" can only be used for encoding
self.assertRaises(
TypeError,
codecs.backslashreplace_errors,
UnicodeDecodeError("ascii", bytearray(b"\xff"), 0, 1, "ouch")
)
self.assertRaises(
TypeError,
codecs.backslashreplace_errors,
UnicodeTranslateError("\u3042", 0, 1, "ouch")
)
# Use the correct exception
self.assertEqual(
codecs.backslashreplace_errors(
@ -701,6 +695,16 @@ class CodecCallbackTest(unittest.TestCase):
UnicodeEncodeError("ascii", "\udfff", 0, 1, "ouch")),
("\\udfff", 1)
)
self.assertEqual(
codecs.backslashreplace_errors(
UnicodeDecodeError("ascii", bytearray(b"\xff"), 0, 1, "ouch")),
("\\xff", 1)
)
self.assertEqual(
codecs.backslashreplace_errors(
UnicodeTranslateError("\u3042", 0, 1, "ouch")),
("\\u3042", 1)
)
def test_badhandlerresults(self):
results = ( 42, "foo", (1,2,3), ("foo", 1, 3), ("foo", None), ("foo",), ("foo", 1, 3), ("foo", None), ("foo",) )

56
Lib/test/test_codecs.py
View File

@ -378,6 +378,10 @@ class ReadTest(MixInCheckStateHandling):
before + after)
self.assertEqual(test_sequence.decode(self.encoding, "replace"),
before + self.ill_formed_sequence_replace + after)
backslashreplace = ''.join('\\x%02x' % b
for b in self.ill_formed_sequence)
self.assertEqual(test_sequence.decode(self.encoding, "backslashreplace"),
before + backslashreplace + after)
class UTF32Test(ReadTest, unittest.TestCase):
encoding = "utf-32"
@ -1300,14 +1304,19 @@ class UnicodeInternalTest(unittest.TestCase):
"unicode_internal")
if sys.byteorder == "little":
invalid = b"\x00\x00\x11\x00"
invalid_backslashreplace = r"\x00\x00\x11\x00"
else:
invalid = b"\x00\x11\x00\x00"
invalid_backslashreplace = r"\x00\x11\x00\x00"
with support.check_warnings():
self.assertRaises(UnicodeDecodeError,
invalid.decode, "unicode_internal")
with support.check_warnings():
self.assertEqual(invalid.decode("unicode_internal", "replace"),
'\ufffd')
with support.check_warnings():
self.assertEqual(invalid.decode("unicode_internal", "backslashreplace"),
invalid_backslashreplace)
@unittest.skipUnless(SIZEOF_WCHAR_T == 4, 'specific to 32-bit wchar_t')
def test_decode_error_attributes(self):
@ -2042,6 +2051,16 @@ class CharmapTest(unittest.TestCase):
("ab\ufffd", 3)
)
self.assertEqual(
codecs.charmap_decode(b"\x00\x01\x02", "backslashreplace", "ab"),
("ab\\x02", 3)
)
self.assertEqual(
codecs.charmap_decode(b"\x00\x01\x02", "backslashreplace", "ab\ufffe"),
("ab\\x02", 3)
)
self.assertEqual(
codecs.charmap_decode(b"\x00\x01\x02", "ignore", "ab"),
("ab", 3)
@ -2118,6 +2137,25 @@ class CharmapTest(unittest.TestCase):
("ab\ufffd", 3)
)
self.assertEqual(
codecs.charmap_decode(b"\x00\x01\x02", "backslashreplace",
{0: 'a', 1: 'b'}),
("ab\\x02", 3)
)
self.assertEqual(
codecs.charmap_decode(b"\x00\x01\x02", "backslashreplace",
{0: 'a', 1: 'b', 2: None}),
("ab\\x02", 3)
)
# Issue #14850
self.assertEqual(
codecs.charmap_decode(b"\x00\x01\x02", "backslashreplace",
{0: 'a', 1: 'b', 2: '\ufffe'}),
("ab\\x02", 3)
)
self.assertEqual(
codecs.charmap_decode(b"\x00\x01\x02", "ignore",
{0: 'a', 1: 'b'}),
@ -2194,6 +2232,18 @@ class CharmapTest(unittest.TestCase):
("ab\ufffd", 3)
)
self.assertEqual(
codecs.charmap_decode(b"\x00\x01\x02", "backslashreplace",
{0: a, 1: b}),
("ab\\x02", 3)
)
self.assertEqual(
codecs.charmap_decode(b"\x00\x01\x02", "backslashreplace",
{0: a, 1: b, 2: 0xFFFE}),
("ab\\x02", 3)
)
self.assertEqual(
codecs.charmap_decode(b"\x00\x01\x02", "ignore",
{0: a, 1: b}),
@ -2253,9 +2303,13 @@ class TypesTest(unittest.TestCase):
self.assertRaises(UnicodeDecodeError, codecs.unicode_escape_decode, br"\U00110000")
self.assertEqual(codecs.unicode_escape_decode(r"\U00110000", "replace"), ("\ufffd", 10))
self.assertEqual(codecs.unicode_escape_decode(r"\U00110000", "backslashreplace"),
(r"\x5c\x55\x30\x30\x31\x31\x30\x30\x30\x30", 10))
self.assertRaises(UnicodeDecodeError, codecs.raw_unicode_escape_decode, br"\U00110000")
self.assertEqual(codecs.raw_unicode_escape_decode(r"\U00110000", "replace"), ("\ufffd", 10))
self.assertEqual(codecs.raw_unicode_escape_decode(r"\U00110000", "backslashreplace"),
(r"\x5c\x55\x30\x30\x31\x31\x30\x30\x30\x30", 10))
class UnicodeEscapeTest(unittest.TestCase):
@ -2894,11 +2948,13 @@ class CodePageTest(unittest.TestCase):
(b'[\xff]', 'strict', None),
(b'[\xff]', 'ignore', '[]'),
(b'[\xff]', 'replace', '[\ufffd]'),
(b'[\xff]', 'backslashreplace', '[\\xff]'),
(b'[\xff]', 'surrogateescape', '[\udcff]'),
(b'[\xff]', 'surrogatepass', None),
(b'\x81\x00abc', 'strict', None),
(b'\x81\x00abc', 'ignore', '\x00abc'),
(b'\x81\x00abc', 'replace', '\ufffd\x00abc'),
(b'\x81\x00abc', 'backslashreplace', '\\xff\x00abc'),
))
def test_cp1252(self):

3
Misc/NEWS
View File

@ -10,6 +10,9 @@ Release date: TBA
Core and Builtins
-----------------
- Issue #22286: The "backslashreplace" error handlers now works with
decoding and translating.
- Issue #23253: Delay-load ShellExecute[AW] in os.startfile for reduced
startup overhead on Windows.

152
Python/codecs.c
View File

@ -864,74 +864,112 @@ PyObject *PyCodec_XMLCharRefReplaceErrors(PyObject *exc)
PyObject *PyCodec_BackslashReplaceErrors(PyObject *exc)
{
PyObject *object;
Py_ssize_t i;
Py_ssize_t start;
Py_ssize_t end;
PyObject *res;
unsigned char *outp;
int ressize;
Py_UCS4 c;
if (PyObject_IsInstance(exc, PyExc_UnicodeDecodeError)) {
unsigned char *p;
if (PyUnicodeDecodeError_GetStart(exc, &start))
return NULL;
if (PyUnicodeDecodeError_GetEnd(exc, &end))
return NULL;
if (!(object = PyUnicodeDecodeError_GetObject(exc)))
return NULL;
if (!(p = (unsigned char*)PyBytes_AsString(object))) {
Py_DECREF(object);
return NULL;
}
res = PyUnicode_New(4 * (end - start), 127);
if (res == NULL) {
Py_DECREF(object);
return NULL;
}
outp = PyUnicode_1BYTE_DATA(res);
for (i = start; i < end; i++, outp += 4) {
unsigned char c = p[i];
outp[0] = '\\';
outp[1] = 'x';
outp[2] = Py_hexdigits[(c>>4)&0xf];
outp[3] = Py_hexdigits[c&0xf];
}
assert(_PyUnicode_CheckConsistency(res, 1));
Py_DECREF(object);
return Py_BuildValue("(Nn)", res, end);
}
if (PyObject_IsInstance(exc, PyExc_UnicodeEncodeError)) {
PyObject *restuple;
PyObject *object;
Py_ssize_t i;
Py_ssize_t start;
Py_ssize_t end;
PyObject *res;
unsigned char *outp;
Py_ssize_t ressize;
Py_UCS4 c;
if (PyUnicodeEncodeError_GetStart(exc, &start))
return NULL;
if (PyUnicodeEncodeError_GetEnd(exc, &end))
return NULL;
if (!(object = PyUnicodeEncodeError_GetObject(exc)))
return NULL;
if (end - start > PY_SSIZE_T_MAX / (1+1+8))
end = start + PY_SSIZE_T_MAX / (1+1+8);
for (i = start, ressize = 0; i < end; ++i) {
/* object is guaranteed to be "ready" */
c = PyUnicode_READ_CHAR(object, i);
if (c >= 0x10000) {
ressize += 1+1+8;
}
else if (c >= 0x100) {
ressize += 1+1+4;
}
else
ressize += 1+1+2;
}
res = PyUnicode_New(ressize, 127);
if (res == NULL) {
Py_DECREF(object);
}
else if (PyObject_IsInstance(exc, PyExc_UnicodeTranslateError)) {
if (PyUnicodeTranslateError_GetStart(exc, &start))
return NULL;
if (PyUnicodeTranslateError_GetEnd(exc, &end))
return NULL;
if (!(object = PyUnicodeTranslateError_GetObject(exc)))
return NULL;
}
for (i = start, outp = PyUnicode_1BYTE_DATA(res);
i < end; ++i) {
c = PyUnicode_READ_CHAR(object, i);
*outp++ = '\\';
if (c >= 0x00010000) {
*outp++ = 'U';
*outp++ = Py_hexdigits[(c>>28)&0xf];
*outp++ = Py_hexdigits[(c>>24)&0xf];
*outp++ = Py_hexdigits[(c>>20)&0xf];
*outp++ = Py_hexdigits[(c>>16)&0xf];
*outp++ = Py_hexdigits[(c>>12)&0xf];
*outp++ = Py_hexdigits[(c>>8)&0xf];
}
else if (c >= 0x100) {
*outp++ = 'u';
*outp++ = Py_hexdigits[(c>>12)&0xf];
*outp++ = Py_hexdigits[(c>>8)&0xf];
}
else
*outp++ = 'x';
*outp++ = Py_hexdigits[(c>>4)&0xf];
*outp++ = Py_hexdigits[c&0xf];
}
assert(_PyUnicode_CheckConsistency(res, 1));
restuple = Py_BuildValue("(Nn)", res, end);
Py_DECREF(object);
return restuple;
}
else {
wrong_exception_type(exc);
return NULL;
}
if (end - start > PY_SSIZE_T_MAX / (1+1+8))
end = start + PY_SSIZE_T_MAX / (1+1+8);
for (i = start, ressize = 0; i < end; ++i) {
/* object is guaranteed to be "ready" */
c = PyUnicode_READ_CHAR(object, i);
if (c >= 0x10000) {
ressize += 1+1+8;
}
else if (c >= 0x100) {
ressize += 1+1+4;
}
else
ressize += 1+1+2;
}
res = PyUnicode_New(ressize, 127);
if (res == NULL) {
Py_DECREF(object);
return NULL;
}
outp = PyUnicode_1BYTE_DATA(res);
for (i = start; i < end; ++i) {
c = PyUnicode_READ_CHAR(object, i);
*outp++ = '\\';
if (c >= 0x00010000) {
*outp++ = 'U';
*outp++ = Py_hexdigits[(c>>28)&0xf];
*outp++ = Py_hexdigits[(c>>24)&0xf];
*outp++ = Py_hexdigits[(c>>20)&0xf];
*outp++ = Py_hexdigits[(c>>16)&0xf];
*outp++ = Py_hexdigits[(c>>12)&0xf];
*outp++ = Py_hexdigits[(c>>8)&0xf];
}
else if (c >= 0x100) {
*outp++ = 'u';
*outp++ = Py_hexdigits[(c>>12)&0xf];
*outp++ = Py_hexdigits[(c>>8)&0xf];
}
else
*outp++ = 'x';
*outp++ = Py_hexdigits[(c>>4)&0xf];
*outp++ = Py_hexdigits[c&0xf];
}
assert(_PyUnicode_CheckConsistency(res, 1));
Py_DECREF(object);
return Py_BuildValue("(Nn)", res, end);
}
static _PyUnicode_Name_CAPI *ucnhash_CAPI = NULL;
@ -1444,8 +1482,8 @@ static int _PyCodecRegistry_Init(void)
backslashreplace_errors,
METH_O,
PyDoc_STR("Implements the 'backslashreplace' error handling, "
"which replaces an unencodable character with a "
"backslashed escape sequence.")
"which replaces malformed data with a backslashed "
"escape sequence.")
}
},
{