% Copyright (C) 2002-2003 David Roundy
%
% This program is free software; you can redistribute it and/or modify
% it under the terms of the GNU General Public License as published by
% the Free Software Foundation; either version 2, or (at your option)
% any later version.
%
% This program is distributed in the hope that it will be useful,
% but WITHOUT ANY WARRANTY; without even the implied warranty of
% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
% GNU General Public License for more details.
%
% You should have received a copy of the GNU General Public License
% along with this program; see the file COPYING. If not, write to
% the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
% Boston, MA 02110-1301, USA.
\chapter{Diff}
\begin{code}
{-# OPTIONS_GHC -cpp -fglasgow-exts #-}
#include "gadts.h"
module Darcs.Diff ( smart_diff, sync, cmp
#ifndef GADT_WITNESSES
, diff_files
#endif
) where
import System.Posix
( setFileTimes )
import System.IO ( IOMode(ReadMode), hFileSize, hClose )
import System.Directory ( doesDirectoryExist, doesFileExist,
getDirectoryContents,
)
import Control.Monad ( liftM, when )
import Data.List ( sort
#ifndef GADT_WITNESSES
, intersperse
#endif
)
import FastPackedString ( hGetPS, lengthPS
#ifndef GADT_WITNESSES
, PackedString, is_funky, nilPS
, linesPS, nullPS, lastPS, takePS,
#endif
)
import Darcs.SlurpDirectory ( Slurpy, slurp_name, is_dir, is_file,
get_dircontents, get_filecontents,
get_mtime, get_length,
undefined_time
#ifndef GADT_WITNESSES
, FileContents, undefined_size
#endif
)
#ifndef GADT_WITNESSES
import Darcs.FilePathUtils ( (///) )
#endif
import Darcs.Patch ( Prim
#ifndef GADT_WITNESSES
, hunk, canonize, rmfile, rmdir
, addfile, adddir
, binary, invert
#endif
)
import System.IO ( openBinaryFile )
import Darcs.Repository.Prefs ( FileType(..) )
import Darcs.Flags ( DarcsFlag(..) )
import Darcs.Utils ( catchall )
import Darcs.Patch.Ordered ( FL(..)
#ifndef GADT_WITNESSES
, (+>+)
#endif
)
#ifndef GADT_WITNESSES
#include "impossible.h"
#endif
\end{code}
The diff function takes a recursive diff of two slurped-up directory trees.
The code involved is actually pretty trivial. \verb!paranoid_diff! runs a
diff in which we don't make the assumption that files with the same
modification time are identical.
\begin{code}
smart_diff :: [DarcsFlag]
-> (FilePath -> FileType) -> Slurpy -> Slurpy -> FL Prim C(x y)
#ifdef GADT_WITNESSES
smart_diff = undefined
#else
smart_diff opts wt s1 s2
= gendiff (ignore_times, look_for_adds, summary) wt [] s1 s2 NilFL
where ignore_times = IgnoreTimes `elem` opts
look_for_adds = LookForAdds `elem` opts
-- NoSummary/Summary both present gives False
-- Just Summary gives True
-- Just NoSummary gives False
-- Neither gives False
summary = Summary `elem` opts && NoSummary `notElem` opts
mk_filepath :: [FilePath] -> FilePath
mk_filepath fps = concat $ intersperse "/" $ reverse fps
gendiff :: (Bool,Bool,Bool)
-> (FilePath -> FileType) -> [FilePath] -> Slurpy -> Slurpy
-> (FL Prim -> FL Prim)
gendiff opts@(isparanoid,_,_) wt fps s1 s2
| is_file s1 && is_file s2 && maybe_differ =
case wt n2 of
TextFile -> diff_files f b1 b2
BinaryFile -> if b1 /= b2 then (binary f b1 b2:>:)
else id
| is_dir s1 && is_dir s2 =
let fps' = case n2 of
"." -> fps
_ -> n2:fps
in fps' `seq` recur_diff opts (wt . (n2///)) fps' dc1 dc2
| otherwise = id
where n2 = slurp_name s2
f = mk_filepath (n2:fps)
b1 = get_filecontents s1
b2 = get_filecontents s2
dc1 = get_dircontents s1
dc2 = get_dircontents s2
maybe_differ = isparanoid
|| get_mtime s1 == undefined_time
|| get_mtime s1 /= get_mtime s2
|| get_length s1 == undefined_size
|| get_length s1 /= get_length s2
-- recur_diff or recursive diff
-- First parameter is (IgnoreTimes?, LookforAdds?, Summary?)
recur_diff :: (Bool,Bool,Bool)
-> (FilePath -> FileType) -> [FilePath] -> [Slurpy] -> [Slurpy]
-> (FL Prim -> FL Prim)
recur_diff _ _ _ [] [] = id
recur_diff opts@(_,doadd,summary) wt fps (s:ss) (s':ss')
-- this is the case if a file has been removed in the working directory
| s < s' = diff_removed wt fps s . recur_diff opts wt fps ss (s':ss')
-- this next case is when there is a file in the directory that is not
-- in the repository (ie, not managed by darcs)
| s > s' = let rest = recur_diff opts wt fps (s:ss) ss'
in if not doadd then rest
else diff_added summary wt fps s' . rest
-- actually compare the files because the names match
| s == s' = gendiff opts wt fps s s' . recur_diff opts wt fps ss ss'
recur_diff opts wt fps (s:ss) [] =
diff_removed wt fps s . recur_diff opts wt fps ss []
recur_diff opts@(_,True,summary) wt fps [] (s':ss') =
diff_added summary wt fps s' . recur_diff opts wt fps [] ss'
recur_diff (_,False,_) _ _ [] _ = id
recur_diff _ _ _ _ _ = impossible
-- creates a diff for a file or directory which needs to be added to the
-- repository
diff_added :: Bool -> (FilePath -> FileType) -> [FilePath] -> Slurpy
-> (FL Prim -> FL Prim)
diff_added summary wt fps s
| is_file s = case wt n of
TextFile -> (addfile f:>:) .
(if summary
then id
else diff_from_empty id f (get_filecontents s))
BinaryFile -> (addfile f:>:) .
(if summary then id else
(bin_patch f nilPS (get_filecontents s)))
| otherwise {- is_dir s -} =
(adddir f:>:)
. foldr (.) id (map (diff_added summary wt (n:fps)) (get_dircontents s))
where n = slurp_name s
f = mk_filepath (n:fps)
get_text :: FileContents -> [PackedString]
get_text = linesPS
empt :: FileContents
empt = nilPS
diff_files :: FilePath -> FileContents -> FileContents
-> (FL Prim -> FL Prim)
diff_files f o n | get_text o == [nilPS] && get_text n == [nilPS] = id
| get_text o == [nilPS] = diff_from_empty id f n
| get_text n == [nilPS] = diff_from_empty invert f o
diff_files f o n = if o == n
then id
else if has_bin o || has_bin n
then (binary f o n:>:)
else (canonize (hunk f 1 (linesPS o) (linesPS n)) +>+)
diff_from_empty :: (Prim -> Prim) -> FilePath -> FileContents
-> (FL Prim -> FL Prim)
diff_from_empty inv f b =
if b == nilPS
then id
else let p = if has_bin b
then binary f nilPS b
else if lastPS b == '\n'
then hunk f 1 [] $ init $ linesPS b
else hunk f 1 [nilPS] $ linesPS b
in (inv p:>:)
{- | We take a PackedString which represents a file's contents, and we check to see
whether it is a 'binary' file or a 'textual' file. We define a textual file as any file
which does not contain two magic characters, '\0' (the NULL character on Unix) and '^Z'
(Control-Z, a DOS convention).
Note that to improve performance, we won't examine *all* of the string, because that
falls down on large files, but just the first 4096 characters. -}
has_bin :: FileContents -> Bool
has_bin = is_funky . takePS 4096
#endif
\end{code}
\begin{code}
#ifndef GADT_WITNESSES
bin_patch :: FilePath -> PackedString -> PackedString
-> FL Prim -> FL Prim
bin_patch f o n | nullPS o && nullPS n = id
| otherwise = (binary f o n:>:)
#endif
\end{code}
\begin{code}
#ifndef GADT_WITNESSES
diff_removed :: (FilePath -> FileType) -> [FilePath] -> Slurpy
-> (FL Prim -> FL Prim)
diff_removed wt fps s
| is_file s = case wt n of
TextFile -> diff_files f (get_filecontents s) empt
. (rmfile f:>:)
BinaryFile -> (bin_patch f
(get_filecontents s) nilPS)
. (rmfile f:>:)
| otherwise {- is_dir s -}
= foldr (.) (rmdir f:>:)
$ map (diff_removed wt (n:fps)) (get_dircontents s)
where n = slurp_name s
f = mk_filepath (n:fps)
#endif
\end{code}
\begin{code}
sync :: String -> Slurpy -> Slurpy -> IO ()
sync path s1 s2
| is_file s1 && is_file s2 &&
(get_mtime s1 == undefined_time || get_mtime s1 /= get_mtime s2) &&
get_length s1 == get_length s2 &&
get_filecontents s1 == get_filecontents s2 =
set_mtime n (get_mtime s2)
| is_dir s1 && is_dir s2
= n2 `seq` recur_sync n (get_dircontents s1) (get_dircontents s2)
| otherwise = return ()
where n2 = slurp_name s2
n = path++"/"++n2
set_mtime fname ctime = setFileTimes fname ctime ctime
`catchall` return ()
recur_sync _ [] _ = return ()
recur_sync _ _ [] = return ()
recur_sync p (s:ss) (s':ss')
| s < s' = recur_sync p ss (s':ss')
| s > s' = recur_sync p (s:ss) ss'
| otherwise = do sync p s s'
recur_sync p ss ss'
\end{code}
\begin{code}
cmp :: FilePath -> FilePath -> IO Bool
cmp p1 p2 = do
dir1 <- doesDirectoryExist p1
dir2 <- doesDirectoryExist p2
file1 <- doesFileExist p1
file2 <- doesFileExist p2
if dir1 && dir2
then cmpdir p1 p2
else if file1 && file2
then cmpfile p1 p2
else return False
cmpdir :: FilePath -> FilePath -> IO Bool
cmpdir d1 d2 = do
fn1 <- liftM (filter (\f->f/="." && f /="..")) $ getDirectoryContents d1
fn2 <- liftM (filter (\f->f/="." && f /="..")) $ getDirectoryContents d2
if sort fn1 /= sort fn2
then return False
else andIO $ map (\fn-> cmp (d1++"/"++fn) (d2++"/"++fn)) fn1
andIO :: [IO Bool] -> IO Bool
andIO (iob:iobs) = do b <- iob
if b then andIO iobs else return False
andIO [] = return True
cmpfile :: FilePath -> FilePath -> IO Bool
cmpfile f1 f2 = do
h1 <- openBinaryFile f1 ReadMode
h2 <- openBinaryFile f2 ReadMode
l1 <- hFileSize h1
l2 <- hFileSize h2
if l1 /= l2
then do hClose h1
hClose h2
putStrLn $ "different file lengths for "++f1++" and "++f2
return False
else do b <- hcmp h1 h2
when (not b) $ putStrLn $ "files "++f1++" and "++f2++" differ"
hClose h1
hClose h2
return b
where hcmp h1 h2 = do c1 <- hGetPS h1 1024
c2 <- hGetPS h2 1024
if c1 /= c2
then return False
else if lengthPS c1 == 1024
then hcmp h1 h2
else return True
\end{code}