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HTML diff from I2 - works better than the original

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Alexey Verkhovsky 2005-11-14 10:13:18 +00:00
parent 0b1a80a852
commit 8f33b8e549
1 changed files with 241 additions and 227 deletions
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lib/diff.rb
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@ -32,27 +32,101 @@ module Enumerable
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 ? ']' : '>'
out.push cur
cur, mode = '', :char
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
end
end
out.push(cur)
out.delete ''
out.map {|elt| newline?(elt) ? elt : elt.chomp}
end
end
class SequenceMatcher
def initialize(a=[''], b=[''], isjunk=nil, byline=false)
a = (!byline and a.kind_of? String) ? a.split(//) : a
b = (!byline and b.kind_of? String) ? b.split(//) : b
@isjunk = isjunk || proc {}
set_seqs a, b
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_seqs(a, b)
set_seq_a a
set_seq_b b
def set_sequences(a, b)
set_sequence_a a
set_sequence_b b
end
def set_seq_a(a)
def set_sequence_a(a)
@a = a
@matching_blocks = @opcodes = nil
end
def set_seq_b(b)
def set_sequence_b(b)
@b = b
@matching_blocks = @opcodes = nil
chain_b
@ -60,28 +134,26 @@ module Diff
def chain_b
@fullbcount = nil
@b2j = {}
pophash = {}
@b2j = {}
pophash = {}
junkdict = {}
@b.each_with_index do |elt, i|
@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 i
indices.push idx
end
else
@b2j[elt] = [i]
@b2j[elt] = [idx]
end
end
pophash.each_key { |elt| @b2j.delete elt }
junkdict = {}
unless @isjunk.nil?
[pophash, @b2j].each do |d|
d.each_key do |elt|
@ -93,24 +165,20 @@ module Diff
end
end
@isbjunk = junkdict.method(:has_key?)
@isbjunk = junkdict.method(:has_key?)
@isbpopular = junkdict.method(:has_key?)
end
def find_longest_match(alo, ahi, blo, bhi)
besti, bestj, bestsize = alo, blo, 0
def find_longest_match(a_low, a_high, b_low, b_high)
besti, bestj, bestsize = a_low, b_low, 0
j2len = {}
(alo..ahi).step do |i|
(a_low..a_high).step do |i|
newj2len = {}
(@b2j[@a[i]] || []).each do |j|
if j < blo
next
end
if j >= bhi
break
end
next if j < b_low
break if j >= b_high
k = newj2len[j] = (j2len[j - 1] || 0) + 1
if k > bestsize
@ -120,26 +188,21 @@ module Diff
j2len = newj2len
end
while besti > alo and bestj > blo and
not @isbjunk.call(@b[bestj-1]) and
@a[besti-1] == @b[bestj-1]
besti, bestj, bestsize = besti-1, bestj-1, bestsize+1
while besti > a_low and bestj > b_low and not @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 < ahi and bestj+bestsize < bhi and
not @isbjunk.call(@b[bestj+bestsize]) and
@a[besti+bestsize] == @b[bestj+bestsize]
while besti + bestsize < a_high and bestj + bestsize < b_high and
not @isbjunk.call(@b[bestj + bestsize]) and
@a[besti + bestsize] == @b[bestj + bestsize]
bestsize += 1
end
while besti > alo and bestj > blo and
@isbjunk.call(@b[bestj-1]) and
@a[besti-1] == @b[bestj-1]
besti, bestj, bestsize = besti-1, bestj-1, bestsize+1
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 < ahi and bestj+bestsize < bhi and
@isbjunk.call(@b[bestj+bestsize]) and
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
@ -148,32 +211,27 @@ module Diff
end
def get_matching_blocks
return @matching_blocks unless @matching_blocks.nil? or
@matching_blocks.empty?
return @matching_blocks unless @matching_blocks.nil_or_empty?
@matching_blocks = []
la, lb = @a.length, @b.length
match_block_helper(0, la, 0, lb, @matching_blocks)
@matching_blocks.push [la, lb, 0]
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(alo, ahi, blo, bhi, answer)
i, j, k = x = find_longest_match(alo, ahi, blo, bhi)
if not k.zero?
if alo < i and blo < j
match_block_helper(alo, i, blo, j, answer)
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 < ahi and j + k < bhi
match_block_helper(i + k, ahi, j + k, bhi, answer)
if i + k < a_high and j + k < b_high
match_block_helper(i + k, a_high, j + k, b_high, answer)
end
end
end
def get_opcodes
unless @opcodes.nil? or @opcodes.empty?
return @opcodes
end
return @opcodes unless @opcodes.nil_or_empty?
i = j = 0
@opcodes = answer = []
@ -187,31 +245,29 @@ module Diff
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
return answer
answer
end
# XXX: untested
def get_grouped_opcodes(n=3)
def get_grouped_opcodes(n = 3)
codes = get_opcodes
if codes[0][0] == :equal
tag, i1, i2, j1, j2 = codes[0]
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[-1][0] == :equal
tag, i1, i2, j1, j2 = codes[-1]
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
if tag == :equal and i2 - i1 > nn
group.push [tag, i1, [i2, i1 + n].min, j1, [j2, j1 + n].min]
yield group
group = []
@ -219,226 +275,184 @@ module Diff
group.push [tag, i1, i2, j1 ,j2]
end
end
if group and group.length != 1 and group[0][0] == :equal
yield group
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[-1]
sum + triple.last
end
Diff.calculate_ratio(matches, @a.length + @b.length)
Diff.calculate_ratio(matches, @a.size + @b.size)
end
def quick_ratio
if @fullbcount.nil? or @fullbcount.empty?
if @fullbcount.nil_or_empty?
@fullbcount = {}
@b.each do |elt|
@fullbcount[elt] = (@fullbcount[elt] || 0) + 1
end
end
avail = {}
avail = {}
matches = 0
@a.each do |elt|
if avail.has_key? elt
numb = avail[elt]
else
numb = @fullbcount[elt] || 0
end
numb = avail.has_key?(elt) ? avail[elt] : (@fullbcount[elt] || 0)
avail[elt] = numb - 1
if numb > 0
matches += 1
end
matches += 1 if numb > 0
end
Diff.calculate_ratio matches, @a.length + @b.length
Diff.calculate_ratio matches, @a.size + @b.size
end
def real_quick_ratio
la, lb = @a.length, @b.length
Diff.calculate_ratio([la, lb].min, la + lb)
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
def self.calculate_ratio(matches, length)
return 1.0 if length.zero?
2.0 * matches / length
end
# XXX: untested
def self.get_close_matches(word, possibilities, n=3, cutoff=0.6)
unless n > 0
raise "n must be > 0: #{n}"
end
unless 0.0 <= cutoff and cutoff <= 1.0
raise "cutoff must be in (0.0..1.0): #{cutoff}"
class << self
def calculate_ratio(matches, length)
return 1.0 if length.zero?
2.0 * matches / length
end
result = []
s = SequenceMatcher.new
s.set_seq_b word
possibilities.each do |x|
s.set_seq_a x
if s.real_quick_ratio >= cutoff and
s.quick_ratio >= cutoff and
s.ratio >= cutoff
result.push [s.ratio, x]
# 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
unless result.nil? or result.empty?
result.sort
result.reverse!
result = result[-n..-1]
end
result.collect { |score, x| x }
end
def self.count_leading(line, ch)
i, n = 0, line.length
while i < n and line[i].chr == ch
i += 1
def count_leading(line, ch)
count, size = 0, line.size
count += 1 while count < size and line[count].chr == ch
count
end
i
end
end
module HTMLDiff
include Diff
class Builder
VALID_METHODS = [:replace, :insert, :delete, :equal]
def initialize(a, b)
@a = a
@b = b
@a, @b = a, b
@content = []
end
def do_op(opcode)
@opcode = opcode
op = @opcode[0]
VALID_METHODS.include?(op) or raise(NameError, "Invalid opcode #{op}")
self.method(op).call
op = @opcode.first
raise NameError, "Invalid opcode '#{op}'" unless VALID_METHODS.include? op
send op
end
def result
@content.join('')
@content.join
end
#this methods have to be called via do_op(opcode) so that @opcode is set properly
# 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}\">"
@content += to_add
@content << "</#{tagname}>"
end
# this 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 "more inside" possible.
# this seems to work nice with html containing only paragraphs
# but not sure it works if there are other tags (div, span ... ? ) around
def op_helper(tagname, tagclass, to_add)
@content << to_add.shift while ( HTMLDiff.is_newline(to_add.first) or
HTMLDiff.is_p_close_tag(to_add.first) or
HTMLDiff.is_p_open_tag(to_add.first) )
@content << "<#{tagname} class=\"#{tagclass}\">"
@content += to_add
last_tags = []
last_tags.unshift(@content.pop) while ( HTMLDiff.is_newline(@content.last) or
HTMLDiff.is_p_close_tag(@content.last) or
HTMLDiff.is_p_open_tag(@content.last) )
last_tags.unshift "</#{tagname}>"
@content += last_tags
remove_empty_diff(tagname, tagclass)
end
def remove_empty_diff(tagname, tagclass)
if @content[-2] == "<#{tagname} class=\"#{tagclass}\">" and @content[-1] == "</#{tagname}>" then
@content.pop
@content.pop
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
end
end
def self.is_newline(x)
(x == "\n") or (x == "\r") or (x == "\t")
end
def self.is_p_open_tag(x)
x =~ /\A<(p|li|ul|ol|dir|dt|dl)/
end
def self.is_p_close_tag(x)
x =~ %r!\A</(p|li|ul|ol|dir|dt|dl)!
end
def self.diff(a, b)
a = html2list(a)
b = html2list(b)
out = Builder.new(a, b)
s = SequenceMatcher.new(a, b)
s.get_opcodes.each do |opcode|
out.do_op(opcode)
end
out.result
end
def self.html2list(x)
mode = :char
cur = ''
out = []
x.split('').each do |c|
if mode == :tag
cur += c
if c == '>'
out.push(cur)
cur = ''
mode = :char
# 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}>)
end
# 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
elsif mode == :char
if c == '<'
out.push cur
cur = c
mode = :tag
elsif c =~ /\s/
out.push cur + c
cur = ''
unless to_add.any? {|element| content_to_skip.call element}
@content << wrap_text(to_add, tagname, tagclass)
else
cur += c
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}>)
end
end
#remove_empty_diff(tagname, tagclass)
end
end
out.push cur
out.find_all { |x| x != '' }
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
class << self
include Diff::Utilities
def diff(a, b)
a, b = html2list(explode(a)), 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