# -*- coding: utf-8 -*-
#
# Copyright (C) 2004-2009 Edgewall Software
# Copyright (C) 2004-2006 Christopher Lenz <cmlenz@gmx.de>
# All rights reserved.
#
# This software is licensed as described in the file COPYING, which
# you should have received as part of this distribution. The terms
# are also available at http://trac.edgewall.org/wiki/TracLicense.
#
# This software consists of voluntary contributions made by many
# individuals. For the exact contribution history, see the revision
# history and logs, available at http://trac.edgewall.org/log/.
#
# Author: Christopher Lenz <cmlenz@gmx.de>
from trac.util.html import escape,Markup
from trac.util.text import expandtabs
from difflib import SequenceMatcher
import re
__all__ = ['get_diff_options', 'hdf_diff', 'diff_blocks', 'unified_diff']
def _get_change_extent(str1, str2):
"""
Determines the extent of differences between two strings. Returns a tuple
containing the offset at which the changes start, and the negative offset
at which the changes end. If the two strings have neither a common prefix
nor a common suffix, (0, 0) is returned.
"""
start = 0
limit = min(len(str1), len(str2))
while start < limit and str1[start] == str2[start]:
start += 1
end = -1
limit = limit - start
while -end <= limit and str1[end] == str2[end]:
end -= 1
return (start, end + 1)
def _get_opcodes(fromlines, tolines, ignore_blank_lines=False,
ignore_case=False, ignore_space_changes=False):
"""
Generator built on top of SequenceMatcher.get_opcodes().
This function detects line changes that should be ignored and emits them
as tagged as 'equal', possibly joined with the preceding and/or following
'equal' block.
"""
def is_ignorable(tag, fromlines, tolines):
if tag == 'delete' and ignore_blank_lines:
if ''.join(fromlines) == '':
return True
elif tag == 'insert' and ignore_blank_lines:
if ''.join(tolines) == '':
return True
elif tag == 'replace' and (ignore_case or ignore_space_changes):
if len(fromlines) != len(tolines):
return False
def f(str):
if ignore_case:
str = str.lower()
if ignore_space_changes:
str = ' '.join(str.split())
return str
for i in range(len(fromlines)):
if f(fromlines[i]) != f(tolines[i]):
return False
return True
matcher = SequenceMatcher(None, fromlines, tolines)
previous = None
for tag, i1, i2, j1, j2 in matcher.get_opcodes():
if tag == 'equal':
if previous:
previous = (tag, previous[1], i2, previous[3], j2)
else:
previous = (tag, i1, i2, j1, j2)
else:
if is_ignorable(tag, fromlines[i1:i2], tolines[j1:j2]):
if previous:
previous = 'equal', previous[1], i2, previous[3], j2
else:
previous = 'equal', i1, i2, j1, j2
continue
if previous:
yield previous
yield tag, i1, i2, j1, j2
previous = None
if previous:
yield previous
def _group_opcodes(opcodes, n=3):
"""
Python 2.2 doesn't have SequenceMatcher.get_grouped_opcodes(), so let's
provide equivalent here. The opcodes parameter can be any iterable or
sequence.
This function can also be used to generate full-context diffs by passing
None for the parameter n.
"""
# Full context produces all the opcodes
if n is None:
yield list(opcodes)
return
# Otherwise we leave at most n lines with the tag 'equal' before and after
# every change
nn = n + n
group = []
for idx, (tag, i1, i2, j1, j2) in enumerate(opcodes):
if idx == 0 and tag == 'equal': # Fixup leading unchanged block
i1, j1 = max(i1, i2 - n), max(j1, j2 - n)
elif tag == 'equal' and i2 - i1 > nn:
group.append((tag, i1, min(i2, i1 + n), j1, min(j2, j1 + n)))
yield group
group = []
i1, j1 = max(i1, i2 - n), max(j1, j2 - n)
group.append((tag, i1, i2, j1 ,j2))
if group and not (len(group) == 1 and group[0][0] == 'equal'):
if group[-1][0] == 'equal': # Fixup trailing unchanged block
tag, i1, i2, j1, j2 = group[-1]
group[-1] = tag, i1, min(i2, i1 + n), j1, min(j2, j1 + n)
yield group
def hdf_diff(*args, **kwargs):
return diff_blocks(*args, **kwargs)
def diff_blocks(fromlines, tolines, context=None, tabwidth=8,
ignore_blank_lines=0, ignore_case=0, ignore_space_changes=0):
"""Return an array that is adequate for adding to the data dictionary
See the diff_div.html template.
"""
type_map = {'replace': 'mod', 'delete': 'rem', 'insert': 'add',
'equal': 'unmod'}
space_re = re.compile(' ( +)|^ ')
def htmlify(match):
div, mod = divmod(len(match.group(0)), 2)
return div * ' ' + mod * ' '
def markup_intraline_changes(opcodes):
for tag, i1, i2, j1, j2 in opcodes:
if tag == 'replace' and i2 - i1 == j2 - j1:
for i in range(i2 - i1):
fromline, toline = fromlines[i1 + i], tolines[j1 + i]
(start, end) = _get_change_extent(fromline, toline)
if start != 0 or end != 0:
last = end+len(fromline)
fromlines[i1+i] = fromline[:start] + '\0' + fromline[start:last] + \
'\1' + fromline[last:]
last = end+len(toline)
tolines[j1+i] = toline[:start] + '\0' + toline[start:last] + \
'\1' + toline[last:]
yield tag, i1, i2, j1, j2
changes = []
opcodes = _get_opcodes(fromlines, tolines, ignore_blank_lines, ignore_case,
ignore_space_changes)
for group in _group_opcodes(opcodes, context):
blocks = []
last_tag = None
for tag, i1, i2, j1, j2 in markup_intraline_changes(group):
if tag != last_tag:
blocks.append({'type': type_map[tag],
'base': {'offset': i1, 'lines': []},
'changed': {'offset': j1, 'lines': []}})
if tag == 'equal':
for line in fromlines[i1:i2]:
line = line.expandtabs(tabwidth)
line = space_re.sub(htmlify, escape(line, quotes=False))
blocks[-1]['base']['lines'].append(Markup(unicode(line)))
for line in tolines[j1:j2]:
line = line.expandtabs(tabwidth)
line = space_re.sub(htmlify, escape(line, quotes=False))
blocks[-1]['changed']['lines'].append(Markup(unicode(line)))
else:
if tag in ('replace', 'delete'):
for line in fromlines[i1:i2]:
line = expandtabs(line, tabwidth, '\0\1')
line = escape(line, quotes=False)
line = '<del>'.join([space_re.sub(htmlify, seg)
for seg in line.split('\0')])
line = line.replace('\1', '</del>')
blocks[-1]['base']['lines'].append(
Markup(unicode(line)))
if tag in ('replace', 'insert'):
for line in tolines[j1:j2]:
line = expandtabs(line, tabwidth, '\0\1')
line = escape(line, quotes=False)
line = '<ins>'.join([space_re.sub(htmlify, seg)
for seg in line.split('\0')])
line = line.replace('\1', '</ins>')
blocks[-1]['changed']['lines'].append(
Markup(unicode(line)))
changes.append(blocks)
return changes
def unified_diff(fromlines, tolines, context=None, ignore_blank_lines=0,
ignore_case=0, ignore_space_changes=0):
opcodes = _get_opcodes(fromlines, tolines, ignore_blank_lines, ignore_case,
ignore_space_changes)
for group in _group_opcodes(opcodes, context):
i1, i2, j1, j2 = group[0][1], group[-1][2], group[0][3], group[-1][4]
if i1 == 0 and i2 == 0:
i1, i2 = -1, -1 # support for 'A'dd changes
yield '@@ -%d,%d +%d,%d @@' % (i1 + 1, i2 - i1, j1 + 1, j2 - j1)
for tag, i1, i2, j1, j2 in group:
if tag == 'equal':
for line in fromlines[i1:i2]:
yield ' ' + line
else:
if tag in ('replace', 'delete'):
for line in fromlines[i1:i2]:
yield '-' + line
if tag in ('replace', 'insert'):
for line in tolines[j1:j2]:
yield '+' + line
def get_diff_options(req):
options_data = {}
data = {'options': options_data}
def get_bool_option(name, default=0):
pref = int(req.session.get('diff_' + name, default))
arg = int(req.args.has_key(name))
if req.args.has_key('update') and arg != pref:
req.session['diff_' + name] = arg
else:
arg = pref
return arg
pref = req.session.get('diff_style', 'inline')
style = req.args.get('style', pref)
if req.args.has_key('update') and style != pref:
req.session['diff_style'] = style
data['style'] = style
pref = int(req.session.get('diff_contextlines', 2))
try:
arg = int(req.args.get('contextlines', pref))
except ValueError:
arg = -1
if req.args.has_key('update') and arg != pref:
req.session['diff_contextlines'] = arg
options = ['-U%d' % arg]
options_data['contextlines'] = arg
arg = get_bool_option('ignoreblanklines')
if arg:
options.append('-B')
options_data['ignoreblanklines'] = arg
arg = get_bool_option('ignorecase')
if arg:
options.append('-i')
options_data['ignorecase'] = arg
arg = get_bool_option('ignorewhitespace')
if arg:
options.append('-b')
options_data['ignorewhitespace'] = arg
return (style, options, data)
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