[Python-checkins] cpython (3.3): #20206, #5803: more efficient algorithm that doesn't truncate output.
r.david.murray
python-checkins at python.org
Mon Jan 13 19:31:38 CET 2014
http://hg.python.org/cpython/rev/4c5b1932354b
changeset: 88441:4c5b1932354b
branch: 3.3
parent: 88438:0ce2396a134b
user: R David Murray <rdmurray at bitdance.com>
date: Mon Jan 13 13:19:21 2014 -0500
summary:
#20206, #5803: more efficient algorithm that doesn't truncate output.
This fixes an edge case (20206) where if the input ended in a character
needing encoding but there was no newline on the string, the last byte
of the encoded character would be dropped. The fix is to use a more
efficient algorithm, provided by Serhiy Storchaka (5803), that does not
have the bug.
files:
Lib/email/quoprimime.py | 134 +++++++----------
Lib/test/test_email/test_email.py | 5 +
Misc/NEWS | 4 +
3 files changed, 65 insertions(+), 78 deletions(-)
diff --git a/Lib/email/quoprimime.py b/Lib/email/quoprimime.py
--- a/Lib/email/quoprimime.py
+++ b/Lib/email/quoprimime.py
@@ -53,8 +53,9 @@
# space-wise. Remember that headers and bodies have different sets of safe
# characters. Initialize both maps with the full expansion, and then override
# the safe bytes with the more compact form.
-_QUOPRI_HEADER_MAP = dict((c, '=%02X' % c) for c in range(256))
-_QUOPRI_BODY_MAP = _QUOPRI_HEADER_MAP.copy()
+_QUOPRI_MAP = ['=%02X' % c for c in range(256)]
+_QUOPRI_HEADER_MAP = _QUOPRI_MAP[:]
+_QUOPRI_BODY_MAP = _QUOPRI_MAP[:]
# Safe header bytes which need no encoding.
for c in b'-!*+/' + ascii_letters.encode('ascii') + digits.encode('ascii'):
@@ -121,8 +122,7 @@
def quote(c):
- return '=%02X' % ord(c)
-
+ return _QUOPRI_MAP[ord(c)]
def header_encode(header_bytes, charset='iso-8859-1'):
@@ -140,67 +140,15 @@
if not header_bytes:
return ''
# Iterate over every byte, encoding if necessary.
- encoded = []
- for octet in header_bytes:
- encoded.append(_QUOPRI_HEADER_MAP[octet])
+ encoded = header_bytes.decode('latin1').translate(_QUOPRI_HEADER_MAP)
# Now add the RFC chrome to each encoded chunk and glue the chunks
# together.
- return '=?%s?q?%s?=' % (charset, EMPTYSTRING.join(encoded))
+ return '=?%s?q?%s?=' % (charset, encoded)
-class _body_accumulator(io.StringIO):
-
- def __init__(self, maxlinelen, eol, *args, **kw):
- super().__init__(*args, **kw)
- self.eol = eol
- self.maxlinelen = self.room = maxlinelen
-
- def write_str(self, s):
- """Add string s to the accumulated body."""
- self.write(s)
- self.room -= len(s)
-
- def newline(self):
- """Write eol, then start new line."""
- self.write_str(self.eol)
- self.room = self.maxlinelen
-
- def write_soft_break(self):
- """Write a soft break, then start a new line."""
- self.write_str('=')
- self.newline()
-
- def write_wrapped(self, s, extra_room=0):
- """Add a soft line break if needed, then write s."""
- if self.room < len(s) + extra_room:
- self.write_soft_break()
- self.write_str(s)
-
- def write_char(self, c, is_last_char):
- if not is_last_char:
- # Another character follows on this line, so we must leave
- # extra room, either for it or a soft break, and whitespace
- # need not be quoted.
- self.write_wrapped(c, extra_room=1)
- elif c not in ' \t':
- # For this and remaining cases, no more characters follow,
- # so there is no need to reserve extra room (since a hard
- # break will immediately follow).
- self.write_wrapped(c)
- elif self.room >= 3:
- # It's a whitespace character at end-of-line, and we have room
- # for the three-character quoted encoding.
- self.write(quote(c))
- elif self.room == 2:
- # There's room for the whitespace character and a soft break.
- self.write(c)
- self.write_soft_break()
- else:
- # There's room only for a soft break. The quoted whitespace
- # will be the only content on the subsequent line.
- self.write_soft_break()
- self.write(quote(c))
-
+_QUOPRI_BODY_ENCODE_MAP = _QUOPRI_BODY_MAP[:]
+for c in b'\r\n':
+ _QUOPRI_BODY_ENCODE_MAP[c] = chr(c)
def body_encode(body, maxlinelen=76, eol=NL):
"""Encode with quoted-printable, wrapping at maxlinelen characters.
@@ -226,26 +174,56 @@
if not body:
return body
- # The last line may or may not end in eol, but all other lines do.
- last_has_eol = (body[-1] in '\r\n')
+ # quote speacial characters
+ body = body.translate(_QUOPRI_BODY_ENCODE_MAP)
- # This accumulator will make it easier to build the encoded body.
- encoded_body = _body_accumulator(maxlinelen, eol)
+ soft_break = '=' + eol
+ # leave space for the '=' at the end of a line
+ maxlinelen1 = maxlinelen - 1
- lines = body.splitlines()
- last_line_no = len(lines) - 1
- for line_no, line in enumerate(lines):
- last_char_index = len(line) - 1
- for i, c in enumerate(line):
- if body_check(ord(c)):
- c = quote(c)
- encoded_body.write_char(c, i==last_char_index)
- # Add an eol if input line had eol. All input lines have eol except
- # possibly the last one.
- if line_no < last_line_no or last_has_eol:
- encoded_body.newline()
+ encoded_body = []
+ append = encoded_body.append
- return encoded_body.getvalue()
+ for line in body.splitlines():
+ # break up the line into pieces no longer than maxlinelen - 1
+ start = 0
+ laststart = len(line) - 1 - maxlinelen
+ while start <= laststart:
+ stop = start + maxlinelen1
+ # make sure we don't break up an escape sequence
+ if line[stop - 2] == '=':
+ append(line[start:stop - 1])
+ start = stop - 2
+ elif line[stop - 1] == '=':
+ append(line[start:stop])
+ start = stop - 1
+ else:
+ append(line[start:stop] + '=')
+ start = stop
+
+ # handle rest of line, special case if line ends in whitespace
+ if line and line[-1] in ' \t':
+ room = start - laststart
+ if room >= 3:
+ # It's a whitespace character at end-of-line, and we have room
+ # for the three-character quoted encoding.
+ q = quote(line[-1])
+ elif room == 2:
+ # There's room for the whitespace character and a soft break.
+ q = line[-1] + soft_break
+ else:
+ # There's room only for a soft break. The quoted whitespace
+ # will be the only content on the subsequent line.
+ q = soft_break + quote(line[-1])
+ append(line[start:-1] + q)
+ else:
+ append(line[start:])
+
+ # add back final newline if present
+ if body[-1] in CRLF:
+ append('')
+
+ return eol.join(encoded_body)
diff --git a/Lib/test/test_email/test_email.py b/Lib/test/test_email/test_email.py
--- a/Lib/test/test_email/test_email.py
+++ b/Lib/test/test_email/test_email.py
@@ -4216,6 +4216,11 @@
def test_encode_one_line_eol(self):
self._test_encode('hello\n', 'hello\r\n', eol='\r\n')
+ def test_encode_one_line_eol_after_non_ascii(self):
+ # issue 20206; see changeset 0cf700464177 for why the encode/decode.
+ self._test_encode('hello\u03c5\n'.encode('utf-8').decode('latin1'),
+ 'hello=CF=85\r\n', eol='\r\n')
+
def test_encode_one_space(self):
self._test_encode(' ', '=20')
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -43,6 +43,10 @@
Library
-------
+- Issues #20206 and #5803: Fix edge case in email.quoprimime.encode where it
+ truncated lines ending in a character needing encoding but no newline by
+ using a more efficient algorithm that doesn't have the bug.
+
- Issue #19082: Working xmlrpc.server and xmlrpc.client examples. Both in
modules and in documentation. Initial patch contributed by Vajrasky Kok.
--
Repository URL: http://hg.python.org/cpython
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