%  Copyright (C) 2003,2005 David Roundy
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\subsection{darcs repair}
\begin{code}
module Repair ( repair ) where
import Workaround ( getCurrentDirectory )
import Directory (setCurrentDirectory )
import IO
import System ( exitWith, ExitCode(..) )
import Monad ( when, )

import DarcsCommands
import DarcsArguments ( DarcsFlag( Verbose, Quiet ),
                        any_verbosity, working_repo_dir, umask_option,
                      )
import Patch ( patch2patchinfo )
import Repository ( withRepoLock )
import DarcsRepo ( lazily_read_repo, am_in_repo, get_checkpoint_by_default,
                   apply_patches_with_feedback, simple_feedback )
import Pristine ( identifyPristine, checkPristine, replacePristine )
import Depends ( get_patches_beyond_tag )
import Lock( withTempDir )
import Check ( check_uniqueness )
import Printer ( putDocLn, text )
#include "impossible.h"
\end{code}

\options{repair}
\begin{code}
repair_description :: String
repair_description = "Repair the corrupted repository."
\end{code}
\haskell{repair_help}

\begin{code}
repair_help :: String
repair_help =
 "Repair attempts to fix corruption that may have entered your\n"++
 "repository.\n"
\end{code}

\begin{code}
repair :: DarcsCommand
repair = DarcsCommand {command_name = "repair",
                       command_help = repair_help,
                       command_description = repair_description,
                       command_extra_args = 0,
                       command_extra_arg_help = [],
                       command_command = repair_cmd,
                       command_prereq = am_in_repo,
                       command_get_arg_possibilities = return [],
                       command_argdefaults = nodefaults,
                       command_darcsoptions =
                           [any_verbosity, working_repo_dir, umask_option]}
\end{code}

Repair currently will only repair damage to the pristine tree.
Fortunately this is just the sort of corruption that is most
likely to happen.

\begin{code}
repair_cmd :: [DarcsFlag] -> [String] -> IO ()
repair_cmd opts _ =
  let putVerbose s = when (Verbose `elem` opts) $ putDocLn s
      putInfo s = when (not $ Quiet `elem` opts) $ putDocLn s
      feedback = simple_feedback opts
  in withRepoLock opts $ \_ -> do
  check_uniqueness putVerbose putInfo
  patches <- lazily_read_repo "."
  maybe_chk <- get_checkpoint_by_default opts "."
  formerdir <- getCurrentDirectory
  withTempDir (formerdir++"/_darcs/newpristine") $ \newcur -> do
    putVerbose $ text "Applying patches..."
    case maybe_chk of
        Just chk ->
            case patch2patchinfo chk of
            Just chtg -> do
                putVerbose $ text "I am repairing from a checkpoint."
                apply_patches_with_feedback [] feedback putInfo $
                                                (chtg, Just chk)
                    : reverse (concat $ get_patches_beyond_tag chtg patches)
            Nothing -> impossible -- checkpoint is always a tag
        Nothing -> apply_patches_with_feedback [] feedback putInfo
                   $ reverse $ concat patches
    -- withTempDir ignores error on delete -- hence the hack below.
    setCurrentDirectory formerdir
    cur <- identifyPristine
    is_same <- checkPristine newcur cur
    if is_same
      then do putStrLn "The repository is already consistent, no changes made."
              exitWith ExitSuccess
      else do putStrLn "Fixing pristine tree..."
              replacePristine newcur cur
              exitWith ExitSuccess
\end{code}