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[FIXES BVILD] Further improvement to diff.rb (I hope not to touch this beast again any time soon); See Changes ripped out from WikiController#show, will become a separate action

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This commit is contained in:
Alexey Verkhovsky 2006-03-11 21:27:49 +00:00
parent 0aa87bf348
commit c435bf2f2b
4 changed files with 84 additions and 77 deletions
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98
lib/diff.rb
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@ -23,7 +23,7 @@ module HTMLDiff
def build
split_inputs_to_words
index_new_words
operations.each {|op| perform_operation(op) }
operations.each { |op| perform_operation(op) }
return @content.join
end
@ -33,8 +33,8 @@ module HTMLDiff
end
def index_new_words
@word_indices = {}
@new_words.each_with_index { |word, i| (@word_indices[word] ||= []) << i }
@word_indices = Hash.new { |h, word| h[word] = [] }
@new_words.each_with_index { |word, i| @word_indices[word] << i }
end
def operations
@ -70,10 +70,12 @@ module HTMLDiff
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
if match.size != 0
match_operation = Operation.new(:equal,
match.start_in_old, match.end_in_old,
match.start_in_new, match.end_in_new)
operations << match_operation
end
position_in_old = match.end_in_old
position_in_new = match.end_in_new
@ -87,7 +89,7 @@ module HTMLDiff
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
@ -104,41 +106,63 @@ module HTMLDiff
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
best_match_in_old = start_in_old
best_match_in_new = start_in_new
best_match_size = 0
j2len = {}
match_length_at = Hash.new { |h, index| h[index] = 0 }
(start_in_old..end_in_old).step do |i|
newj2len = {}
(@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
besti, bestj, bestsize = i - k + 1, j - k + 1, k
start_in_old.upto(end_in_old - 1) do |index_in_old|
new_match_length_at = Hash.new { |h, index| h[index] = 0 }
@word_indices[@old_words[index_in_old]].each do |index_in_new|
next if index_in_new < start_in_new
break if index_in_new >= end_in_new
new_match_length = match_length_at[index_in_new - 1] + 1
new_match_length_at[index_in_new] = new_match_length
if new_match_length > best_match_size
best_match_in_old = index_in_old - new_match_length + 1
best_match_in_new = index_in_new - new_match_length + 1
best_match_size = new_match_length
end
end
j2len = newj2len
match_length_at = new_match_length_at
end
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
# best_match_in_old, best_match_in_new, best_match_size = add_matching_words_left(
# best_match_in_old, best_match_in_new, best_match_size, start_in_old, start_in_new)
# best_match_in_old, best_match_in_new, match_size = add_matching_words_right(
# best_match_in_old, best_match_in_new, best_match_size, end_in_old, end_in_new)
return (best_match_size != 0 ? Match.new(best_match_in_old, best_match_in_new, best_match_size) : nil)
end
def add_matching_words_left(match_in_old, match_in_new, match_size, start_in_old, start_in_new)
while match_in_old > start_in_old and
match_in_new > start_in_new and
@old_words[match_in_old - 1] == @new_words[match_in_new - 1]
match_in_old -= 1
match_in_new -= 1
match_size += 1
end
while besti + bestsize < end_in_old and bestj + bestsize < end_in_new and
@old_words[besti + bestsize] == @new_words[bestj + bestsize]
bestsize += 1
end
if bestsize == 0
return nil
else
return Match.new(besti, bestj, bestsize)
[match_in_old, match_in_new, match_size]
end
def add_matching_words_right(match_in_old, match_in_new, match_size, end_in_old, end_in_new)
while match_in_old + match_size < end_in_old and
match_in_new + match_size < end_in_new and
@old_words[match_in_old + match_size] == @new_words[match_in_new + match_size]
match_size += 1
end
[match_in_old, match_in_new, match_size]
end
VALID_METHODS = [:replace, :insert, :delete, :equal]
def perform_operation(operation)
@operation = operation
self.send operation.action, operation
@ -158,7 +182,7 @@ module HTMLDiff
end
def equal(operation)
# no tags to insert, simply copy the matching words from onbe of the versions
# no tags to insert, simply copy the matching words from one of the versions
@content += @new_words[operation.start_in_new...operation.end_in_new]
end
@ -196,9 +220,9 @@ module HTMLDiff
# new: '<p>ab</p><p>c</b>'
# diff result: '<p>a<ins>b</ins></p><p><ins>c</ins></p>'
# this still doesn't guarantee valid HTML (hint: think about diffing a text containing ins or
# del tags), but handles correctly more cases than earlier version.
# del tags), but handles correctly more cases than the earlier version.
#
# PS: Spare a thought for people who write HTML browsers. They live in this ... every day.
# P.S.: Spare a thought for people who write HTML browsers. They live in this ... every day.
def insert_tag(tagname, cssclass, words)
loop do
@ -288,5 +312,5 @@ module HTMLDiff
def diff(a, b)
DiffBuilder.new(a, b).build
end
end