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Refactoring and deleting unused code from lib/diffr.rb until I can understand what it says. Also fixes #256. The build is still broken.

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Alexey Verkhovsky 2006-01-22 21:40:20 +00:00
parent 60c07ca1a2
commit 3ea1ef881f
4 changed files with 298 additions and 509 deletions
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668
lib/diff.rb
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@ -1,205 +1,111 @@
# heavily based off difflib.py - see that file for documentation
# ported from Python by Bill Atkins
module HTMLDiff
# This does not support all features offered by difflib; it
# implements only the subset of features necessary
# to support a Ruby version of HTML Differ. You're welcome to finish this off.
# By default, String#each iterates by line. This isn't really appropriate
# for diff, so often a string will be split by // to get an array of one-
# character strings.
# Some methods in Diff are untested and are not guaranteed to work. The
# methods in HTMLDiff and any methods it calls should work quite well.
# changes by DenisMertz
# * main change:
# ** get the tag soup away
# the tag soup problem was first reported with <p> tags, but it appeared also with
# <li>, <ul> etc... tags
# this version should mostly fix these problems
# ** added a Builder class to manage the creation of the final htmldiff
# * minor changes:
# ** use symbols instead of string to represent opcodes
# ** small fix to html2list
#
module Enumerable
def reduce(init)
result = init
each { |item| result = yield(result, item) }
result
end
end
class Object
def nil_or_empty?
nil? or empty?
end
end
module Diff
module Utilities
def explode(sequence)
sequence.is_a?(String) ? sequence.split(//) : sequence
end
def newline?(char)
%W(\n \r).include? char
end
def tab?(char)
"\t" == char
end
# XXX Could be more robust but unrecognized tags cause an infinite loop so
# better to be permissive
def open_tag?(char)
char =~ /\A<[^>]+>/
end
# See comment for open_tag?
def close_tag?(char)
char =~ %r!\A</[^>]+>!
end
def end_of_tag?(char)
char == '>'
end
def start_of_tag?(char)
char == '<'
end
def html2list(x, use_brackets = false)
mode = :char
cur = ''
out = []
explode(x).each do |char|
case mode
when :tag
if end_of_tag? char
cur += use_brackets ? ']' : '>'
case cur
when '<pre>' then mode = :pre
when '<code>' then mode = :code
else
out.push cur
cur, mode = '', :char
end
else
cur += char
end
when :char
if start_of_tag? char
out.push cur
cur = use_brackets ? '[' : '<'
mode = :tag
elsif /\s/.match char
out.push cur + char
cur = ''
else
cur += char
end
when :pre
if end_of_tag?(char) and cur =~ %r!</pre$!
cur += '>'
out.push cur
cur, mode = '', :char
else
cur += char
end
when :code
if end_of_tag?(char) and cur =~ %r!</code$!
cur += '>'
out.push cur
cur, mode = '', :char
else
cur += char
end
end
end
out.push(cur)
out.delete ''
out.map {|elt| newline?(elt) ? elt : elt.chomp}
end
end
class SequenceMatcher
include Utilities
def initialize(a = [''], b = [''], isjunk = nil, byline = false)
a, b = explode(a), explode(b) unless byline
@isjunk = isjunk || Proc.new {}
set_sequences a, b
end
def set_sequences(a, b)
set_sequence_a a
set_sequence_b b
end
def set_sequence_a(a)
@a = a
@matching_blocks = @opcodes = nil
end
def set_sequence_b(b)
@b = b
@matching_blocks = @opcodes = nil
chain_b
end
def chain_b
@fullbcount = nil
@b2j = {}
pophash = {}
junkdict = {}
@b.each_with_index do |elt, idx|
if @b2j.has_key? elt
indices = @b2j[elt]
if @b.length >= 200 and indices.length * 100 > @b.length
pophash[elt] = 1
indices.clear
else
indices.push idx
end
else
@b2j[elt] = [idx]
end
end
pophash.each_key { |elt| @b2j.delete elt }
unless @isjunk.nil?
[pophash, @b2j].each do |d|
d.each_key do |elt|
if @isjunk.call(elt)
junkdict[elt] = 1
d.delete elt
end
end
end
end
@isbjunk = junkdict.method(:has_key?)
@isbpopular = junkdict.method(:has_key?)
Match = Struct.new(:start_in_old, :start_in_new, :size)
class Match
def end_in_old
self.start_in_old + self.size
end
def find_longest_match(a_low, a_high, b_low, b_high)
besti, bestj, bestsize = a_low, b_low, 0
def end_in_new
self.start_in_new + self.size
end
end
Operation = Struct.new(:action, :start_in_old, :end_in_old, :start_in_new, :end_in_new)
class DiffBuilder
def initialize(old_version, new_version)
@old_version, @new_version = old_version, new_version
@content = []
end
def build
split_inputs_to_words
index_new_words
operations.each {|opcode| perform_operation(opcode)}
return @content.join
end
def split_inputs_to_words
@old_words = convert_html_to_list_of_words(explode(@old_version))
@new_words = convert_html_to_list_of_words(explode(@new_version))
end
def index_new_words
@word_indices = {}
@new_words.each_with_index { |word, i| (@word_indices[word] ||= []) << i }
end
def operations
position_in_old = position_in_new = 0
operations = []
matching_blocks.each do |match|
match_starts_at_current_position_in_old = (position_in_old == match.start_in_old)
match_starts_at_current_position_in_new = (position_in_new == match.start_in_new)
action_upto_match_positions =
case [match_starts_at_current_position_in_old, match_starts_at_current_position_in_new]
when [false, false]
:replace
when [true, false]
:insert
when [false, true]
:delete
else
# this happens if the first few words are same in both versions
:none
end
if action_upto_match_positions != :none
operation_upto_match_positions =
Operation.new(action_upto_match_positions,
position_in_old, match.start_in_old,
position_in_new, match.start_in_new)
operations << operation_upto_match_positions
end
match_operation = Operation.new(:equal,
match.start_in_old, match.end_in_old,
match.start_in_new, match.end_in_new)
operations << match_operation
position_in_old = match.end_in_old
position_in_new = match.end_in_new
end
operations
end
def matching_blocks
matching_blocks = []
recursively_find_matching_blocks(0, @old_words.size, 0, @new_words.size, matching_blocks)
matching_blocks
end
def recursively_find_matching_blocks(start_in_old, end_in_old, start_in_new, end_in_new, matching_blocks)
match = find_match(start_in_old, end_in_old, start_in_new, end_in_new)
if match
if start_in_old < match.start_in_old and start_in_new < match.start_in_new
recursively_find_matching_blocks(
start_in_old, match.start_in_old, start_in_new, match.start_in_new, matching_blocks)
end
matching_blocks << match
if match.end_in_old < end_in_old and match.end_in_new < end_in_new
recursively_find_matching_blocks(
match.end_in_old, end_in_old, match.end_in_new, end_in_new, matching_blocks)
end
end
end
def find_match(start_in_old, end_in_old, start_in_new, end_in_new)
besti, bestj, bestsize = start_in_old, start_in_new, 0
j2len = {}
(a_low..a_high).step do |i|
(start_in_old..end_in_old).step do |i|
newj2len = {}
(@b2j[@a[i]] || []).each do |j|
next if j < b_low
break if j >= b_high
(@word_indices[@old_words[i]] || []).each do |j|
next if j < start_in_new
break if j >= end_in_new
k = newj2len[j] = (j2len[j - 1] || 0) + 1
if k > bestsize
@ -209,271 +115,153 @@ module Diff
j2len = newj2len
end
while besti > a_low and bestj > b_low and not @isbjunk.call(@b[bestj - 1]) and @a[besti - 1] == @b[bestj - 1]
while besti > start_in_old and bestj > start_in_new and @old_words[besti - 1] == @new_words[bestj - 1]
besti, bestj, bestsize = besti - 1, bestj - 1, bestsize + 1
end
while besti + bestsize < a_high and bestj + bestsize < b_high and
not @isbjunk.call(@b[bestj + bestsize]) and
@a[besti + bestsize] == @b[bestj + bestsize]
while besti + bestsize < end_in_old and bestj + bestsize < end_in_new and
@old_words[besti + bestsize] == @new_words[bestj + bestsize]
bestsize += 1
end
while besti > a_low and bestj > b_low and @isbjunk.call(@b[bestj - 1]) and @a[besti - 1] == @b[bestj - 1]
besti, bestj, bestsize = besti - 1, bestj - 1, bestsize + 1
end
while besti + bestsize < a_high and bestj + bestsize < b_high and @isbjunk.call(@b[bestj+bestsize]) and
@a[besti+bestsize] == @b[bestj+bestsize]
bestsize += 1
end
[besti, bestj, bestsize]
end
def get_matching_blocks
return @matching_blocks unless @matching_blocks.nil_or_empty?
@matching_blocks = []
size_of_a, size_of_b = @a.size, @b.size
match_block_helper(0, size_of_a, 0, size_of_b, @matching_blocks)
@matching_blocks.push [size_of_a, size_of_b, 0]
end
def match_block_helper(a_low, a_high, b_low, b_high, answer)
i, j, k = x = find_longest_match(a_low, a_high, b_low, b_high)
unless k.zero?
match_block_helper(a_low, i, b_low, j, answer) if a_low < i and b_low < j
answer.push x
if i + k < a_high and j + k < b_high
match_block_helper(i + k, a_high, j + k, b_high, answer)
end
if bestsize == 0
return nil
else
return Match.new(besti, bestj, bestsize)
end
end
def get_opcodes
return @opcodes unless @opcodes.nil_or_empty?
i = j = 0
@opcodes = answer = []
get_matching_blocks.each do |ai, bj, size|
tag = if i < ai and j < bj
:replace
elsif i < ai
:delete
elsif j < bj
:insert
end
answer.push [tag, i, ai, j, bj] if tag
i, j = ai + size, bj + size
answer.push [:equal, ai, i, bj, j] unless size.zero?
end
answer
end
# XXX: untested
def get_grouped_opcodes(n = 3)
codes = get_opcodes
if codes.first.first == :equal
tag, i1, i2, j1, j2 = codes.first
codes[0] = tag, [i1, i2 - n].max, i2, [j1, j2-n].max, j2
end
if codes.last.first == :equal
tag, i1, i2, j1, j2 = codes.last
codes[-1] = tag, i1, min(i2, i1+n), j1, min(j2, j1+n)
end
nn = n + n
group = []
codes.each do |tag, i1, i2, j1, j2|
if tag == :equal and i2 - i1 > nn
group.push [tag, i1, [i2, i1 + n].min, j1, [j2, j1 + n].min]
yield group
group = []
i1, j1 = [i1, i2-n].max, [j1, j2-n].max
group.push [tag, i1, i2, j1 ,j2]
end
end
yield group if group and group.size != 1 and group.first.first == :equal
end
def ratio
matches = get_matching_blocks.reduce(0) do |sum, triple|
sum + triple.last
end
Diff.calculate_ratio(matches, @a.size + @b.size)
end
def quick_ratio
if @fullbcount.nil_or_empty?
@fullbcount = {}
@b.each do |elt|
@fullbcount[elt] = (@fullbcount[elt] || 0) + 1
end
end
avail = {}
matches = 0
@a.each do |elt|
numb = avail.has_key?(elt) ? avail[elt] : (@fullbcount[elt] || 0)
avail[elt] = numb - 1
matches += 1 if numb > 0
end
Diff.calculate_ratio matches, @a.size + @b.size
end
def real_quick_ratio
size_of_a, size_of_b = @a.size, @b.size
Diff.calculate_ratio([size_of_a, size_of_b].min, size_of_a + size_of_b)
end
protected :chain_b, :match_block_helper
end # end class SequenceMatcher
class << self
def calculate_ratio(matches, length)
return 1.0 if length.zero?
2.0 * matches / length
end
# XXX: untested
def get_close_matches(word, possibilities, n = 3, cutoff = 0.6)
raise "n must be > 0: #{n}" unless n > 0
raise "cutoff must be in (0.0..1.0): #{cutoff}" unless cutoff.between 0.0..1.0
result = []
sequence_matcher = Diff::SequenceMatcher.new
sequence_matcher.set_sequence_b word
possibilities.each do |possibility|
sequence_matcher.set_sequence_a possibility
if sequence_matcher.real_quick_ratio >= cutoff and
sequence_matcher.quick_ratio >= cutoff and
sequence_matcher.ratio >= cutoff
result.push [sequence_matcher.ratio, possibility]
end
end
unless result.nil_or_empty?
result.sort
result.reverse!
result = result[-n..-1]
end
result.map {|score, x| x }
end
def count_leading(line, ch)
count, size = 0, line.size
count += 1 while count < size and line[count].chr == ch
count
end
end
end
module HTMLDiff
include Diff
class Builder
VALID_METHODS = [:replace, :insert, :delete, :equal]
def initialize(a, b)
@a, @b = a, b
@content = []
def perform_operation(operation)
@operation = operation
self.send operation.action, operation
end
def do_op(opcode)
@opcode = opcode
op = @opcode.first
raise NameError, "Invalid opcode '#{op}'" unless VALID_METHODS.include? op
send op
def replace(operation)
delete(operation, 'diffmod')
insert(operation, 'diffmod')
end
def result
@content.join
end
# These methods have to be called via do_op(opcode) so that @opcode is set properly
private
def replace
delete('diffmod')
insert('diffmod')
end
def insert(tagclass = 'diffins')
op_helper('ins', tagclass, @b[@opcode[3]...@opcode[4]])
end
def delete(tagclass = 'diffdel')
op_helper('del', tagclass, @a[@opcode[1]...@opcode[2]])
end
def equal
@content += @b[@opcode[3]...@opcode[4]]
end
# Using this as op_helper would be equivalent to the first version of diff.rb by Bill Atkins
def op_helper_simple(tagname, tagclass, to_add)
@content << %(<#{tagname} class="#{tagclass}">) << to_add << %(</#{tagname}>)
def insert(operation, tagclass = 'diffins')
insert_tag('ins', tagclass, @new_words[operation.start_in_new...operation.end_in_new])
end
def delete(operation, tagclass = 'diffdel')
insert_tag('del', tagclass, @old_words[operation.start_in_old...operation.end_in_old])
end
def equal(operation)
# no tags to insert, simply copy the matching words from onbe of the versions
@content += @new_words[operation.start_in_new...operation.end_in_new]
end
def opening_tag?(item)
item =~ %r!^\s*<[^>]+>\s*$!
end
def closing_tag?(item)
item =~ %r!^\s*</[^>]+>\s*$!
end
def tag?(item)
opening_tag?(item) or closing_tag?(item)
end
# Tries to enclose diff tags (<ins> or <del>) within <p> tags
# As a result the diff tags should be the "most inside" possible.
def insert_tag(tagname, cssclass, words)
unless words.any? { |word| tag?(word) }
@content << wrap_text(words.join, tagname, cssclass)
else
loop do
break if words.empty?
@content << words and break if words.all? { |word| tag?(word) }
# We are outside of a diff tag
@content << words.shift while not words.empty? and tag?(words.first)
@content << %(<#{tagname} class="#{cssclass}">)
# We are inside a diff tag
@content << words.shift until words.empty? or tag?(words.first)
@content << %(</#{tagname}>)
end
end
end
def wrap_text(text, tagname, cssclass)
%(<#{tagname} class="#{cssclass}">#{text}</#{tagname}>)
end
def explode(sequence)
sequence.is_a?(String) ? sequence.split(//) : sequence
end
def end_of_tag?(char)
char == '>'
end
def start_of_tag?(char)
char == '<'
end
def whitespace?(char)
char =~ /\s/
end
def convert_html_to_list_of_words(x, use_brackets = false)
mode = :char
current_word = ''
words = []
# Tries to put <p> tags or newline chars before the opening diff tags (<ins> or <del>)
# or after the ending diff tags.
# As a result the diff tags should be the "most inside" possible.
def op_helper(tagname, tagclass, to_add)
predicate_methods = [:tab?, :newline?, :close_tag?, :open_tag?]
content_to_skip = Proc.new do |item|
predicate_methods.any? {|predicate| HTMLDiff.send(predicate, item)}
end
unless to_add.any? {|element| content_to_skip.call element}
@content << wrap_text(to_add, tagname, tagclass)
else
loop do
@content << to_add and break if to_add.all? {|element| content_to_skip.call element}
# We are outside of a diff tag
@content << to_add.shift while content_to_skip.call to_add.first
@content << %(<#{tagname} class="#{tagclass}">)
# We are inside a diff tag
@content << to_add.shift until content_to_skip.call to_add.first
@content << %(</#{tagname}>)
explode(x).each do |char|
case mode
when :tag
if end_of_tag? char
current_word << (use_brackets ? ']' : '>')
words << current_word
current_word = ''
if whitespace?(char)
mode = :whitespace
else
mode = :char
end
else
current_word << char
end
when :char
if start_of_tag? char
words << current_word unless current_word.empty?
current_word = (use_brackets ? '[' : '<')
mode = :tag
elsif /\s/.match char
words << current_word unless current_word.empty?
current_word = char
mode = :whitespace
else
current_word << char
end
when :whitespace
if start_of_tag? char
words << current_word unless current_word.empty?
current_word = (use_brackets ? '[' : '<')
mode = :tag
elsif /\s/.match char
current_word << char
else
words << current_word unless current_word.empty?
current_word = char
mode = :char
end
else
raise "Unknown mode #{mode.inspect}"
end
#remove_empty_diff(tagname, tagclass)
end
words << current_word unless current_word.empty?
words
end
def wrap_text(text, tagname, tagclass)
%(<#{tagname} class="#{tagclass}">#{text}</#{tagname}>)
end
def remove_empty_diff(tagname, tagclass)
@content = @content[0...-2] if last_elements_empty_diff?(@content, tagname, tagclass)
end
def last_elements_empty_diff?(content, tagname, tagclass)
content[-2] == %(<#{tagname} class="#{tagclass}">) and content.last == %(</#{tagname}>)
end
end # of class Diff Builder
def diff(a, b)
DiffBuilder.new(a, b).build
end
class << self
include Diff::Utilities
def diff(a, b)
a = html2list(explode(a))
b = html2list(explode(b))
out = Builder.new(a, b)
sequence_matcher = Diff::SequenceMatcher.new(a, b)
sequence_matcher.get_opcodes.each {|opcode| out.do_op(opcode)}
out.result
end
end
end
if __FILE__ == $0
if ARGV.size == 2
puts HTMLDiff.diff(IO.read(ARGV.pop), IO.read(ARGV.pop))
else
puts "Usage: html_diff file1 file2"
end
end