มอดูล:Diff

-----------------------------------------------------------------------------
-- Provides functions for diffing text.
--
-- (c) 2007, 2008  Yuri Takhteyev (yuri@freewisdom.org)
-- (c) 2007 Hisham Muhammad
-- Adapted to MediaWiki LUA: User:Ebraminio 
--
-- License: MIT/X, see http://sputnik.freewisdom.org/en/License
-----------------------------------------------------------------------------
SKIP_SEPARATOR = true  -- a constant
IN   = "in"; OUT  = "out"; SAME = "same"  -- token statuses
-----------------------------------------------------------------------------
-- Split a string into tokens.  (Adapted from Gavin Kistner's split on
-- http://lua-users.org/wiki/SplitJoin.
--
-- @param text           A string to be split.
-- @param separator      optional the separator pattern (defaults to any
--                       white space - %s+).
-- @param skip_separator optional don't include the sepator in the results.     
-- @return               A list of tokens.
-----------------------------------------------------------------------------
function split(text, separator, skip_separator)
separator = separator or "%s+"
local parts = {}  
local start = 1
local split_start, split_end = mw.ustring.find(text, separator, start)
while split_start do
table.insert(parts, mw.ustring.sub(text, start, split_start-1))
if not skip_separator then
table.insert(parts, mw.ustring.sub(text, split_start, split_end))
end
start = split_end + 1
split_start, split_end = mw.ustring.find(text, separator, start)
end
if mw.ustring.sub(text, start) ~= "" then
table.insert(parts, mw.ustring.sub(text, start))
end
return parts
end
-----------------------------------------------------------------------------
-- Derives the longest common subsequence of two strings.  This is a faster
-- implementation than one provided by stdlib.  Submitted by Hisham Muhammad. 
-- The algorithm was taken from:
-- http://en.wikibooks.org/wiki/Algorithm_implementation/Strings/Longest_common_subsequence
--
-- @param t1             the first string.
-- @param t2             the second string.
-- @return               the least common subsequence as a matrix.
-----------------------------------------------------------------------------
function quick_LCS(t1, t2)
local m = #t1
local n = #t2
-- Build matrix on demand
local C = {}
local setmetatable = setmetatable
local mt_tbl = {
__index = function(t, k)
tk = 0
return 0
end
}
local mt_C = {
__index = function(t, k)
local tbl = {}
setmetatable(tbl, mt_tbl)
tk = tbl
return tbl
end
}
setmetatable(C, mt_C)
local max = math.max
for i = 1, m+1 do
local ci1 = Ci+1
local ci = Ci
for j = 1, n+1 do
if t1i-1 == t2j-1 then
ci1j+1 = cij + 1
else
ci1j+1 = max(ci1j, cij+1)
end
end
end
return C
end
-----------------------------------------------------------------------------
-- Formats an inline diff as HTML, with  and  tags.
-- 
-- @param tokens         a table of {token, status} pairs.
-- @return               an HTML string.
-----------------------------------------------------------------------------
function format_as_html(tokens)
local diff_buffer = ""
local token, status
for i, token_record in ipairs(tokens) do
token = mw.text.nowiki(token_record1)
status = token_record2
if status == "in" then
diff_buffer = diff_buffer....token..
elseif status == "out" then
diff_buffer = diff_buffer....token..
else 
diff_buffer = diff_buffer..token
end
end
return diff_buffer
end
-----------------------------------------------------------------------------
-- Returns a diff of two strings as a list of pairs, where the first value
-- represents a token and the second the token's status ("same", "in", "out").
--
-- @param old             The "old" text string
-- @param new             The "new" text string
-- @param separator      optional the separator pattern (defaults ot any
--                       white space).
-- @return               A list of annotated tokens.
-----------------------------------------------------------------------------
function diff(old, new, separator)
assert(old); assert(new)
new = split(new, separator); old = split(old, separator)
-- First, compare the beginnings and ends of strings to remove the common
-- prefix and suffix.  Chances are, there is only a small number of tokens
-- in the middle that differ, in which case  we can save ourselves a lot
-- in terms of LCS computation.
local prefix = "" -- common text in the beginning
local suffix = "" -- common text in the end
while old1 and old1 == new1 do
local token = table.remove(old, 1)
table.remove(new, 1)
prefix = prefix..token
end
while old#old and old#old == new#new do
local token = table.remove(old)
table.remove(new)
suffix = token..suffix
end
-- Setup a table that will store the diff (an upvalue for get_diff). We'll
-- store it in the reverse order to allow for tail calls.  We'll also keep
-- in this table functions to handle different events.
local rev_diff = {
put  = function(self, token, type) table.insert(self, {token,type}) end,
ins  = function(self, token) self:put(token, IN) end,
del  = function(self, token) self:put(token, OUT) end,
same = function(self, token) if token then self:put(token, SAME) end end,
}
-- Put the suffix as the first token (we are storing the diff in the
-- reverse order)
rev_diff:same(suffix)
-- Define a function that will scan the LCS matrix backwards and build the
-- diff output recursively.
local function get_diff(C, old, new, i, j)
local old_i = oldi
local new_j = newj
if i >= 1 and j >= 1 and old_i == new_j then
rev_diff:same(old_i)
return get_diff(C, old, new, i-1, j-1)
else
local Cij1 = Cij-1
local Ci1j = Ci-1j
if j >= 1 and (i == 0 or Cij1 >= Ci1j) then
rev_diff:ins(new_j)
return get_diff(C, old, new, i, j-1)
elseif i >= 1 and (j == 0 or Cij1 < Ci1j) then
rev_diff:del(old_i)
return get_diff(C, old, new, i-1, j)
end
end
end
-- Then call it.
get_diff(quick_LCS(old, new), old, new, #old + 1, #new + 1)
-- Put the prefix in at the end
rev_diff:same(prefix)
-- Reverse the diff.
local diff = {}
for i = #rev_diff, 1, -1 do
table.insert(diff, rev_diffi)
end
diff.to_html = format_as_html
return diff
end
-----------------------------------------------------------------------------
-- Wiki diff style, currently just for a line
-----------------------------------------------------------------------------
function wikiDiff(old, new, separator)
local tokens = diff(old, new, separator)
local root = mw.html.create()
root:wikitext(mw.getCurrentFrame():extensionTag('templatestyles', , {src = 'Module:Diff/styles.css'}))
local token, status
-- Override default border-width for browsers that support them.
-- Needed for RTL support; forbidden in TemplateStyles.
local tdSharedStyle = '-webkit-border-end-width: 1px; -webkit-border-start-width: 4px; ' ..
'-moz-border-end-width: 1px; -moz-border-start-width: 4px;'

local is_different = false
for _, token_record in ipairs(tokens) do
if token_record2 ~= SAME then
is_different = true
break
end
end
local tr = root:tag('table'):attr('lang', ):addClass('diff'):tag('tr')
tr:tag('td')
:addClass('diff-marker')
:wikitext(is_different and '−' or ' ')
local deleted = tr
:tag('td')
:cssText(tdSharedStyle)
:addClass(is_different and 'diff-deletedline' or 'diff-context')
:tag('div')
for i, token_record in ipairs(tokens) do
token = mw.text.nowiki(token_record1)
status = token_record2
if status == OUT then
deleted
:tag('del')
:addClass('diffchange')
:addClass('diffchange-inline')
:wikitext(token)
elseif status == SAME then
deleted:wikitext(token)
end
end
tr:tag('td')
:addClass('diff-marker')
:wikitext(is_different and '+' or ' ')
local inserted = tr
:tag('td')
:cssText(tdSharedStyle)
:addClass(is_different and 'diff-addedline' or 'diff-context')
:tag('div')
for i, token_record in ipairs(tokens) do
token = mw.text.nowiki(token_record1)
status = token_record2
if status == IN then
inserted
:tag('ins')
:addClass('diffchange')
:addClass('diffchange-inline')
:wikitext(token)
elseif status == SAME then
inserted:wikitext(token)
end
end
return tostring(root)
end
function main(frame)
return wikiDiff(mw.text.unstrip(mw.text.decode(frame.args1)), mw.text.decode(mw.text.unstrip(frame.args2)), frame.args3 or '%s%.:-+')
end
return {
diff = diff,
wikiDiff = wikiDiff,
main = main
}