ShowContents.lhs

%  Copyright (C) 2007 Eric Kow
%
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\subsubsection{darcs show contents}
\begin{code}
module Darcs.Commands.ShowContents ( show_contents ) where

import Control.Monad ( filterM )
import System.Directory( doesFileExist )
import System.IO ( stdout )

import FastPackedString ( readFilePS, hPutPS )
import Workaround ( getCurrentDirectory )
import Darcs.Utils ( withCurrentDirectory )

import Darcs.Commands ( DarcsCommand(..), nodefaults )
import Darcs.Arguments ( DarcsFlag,
                         match_one,
                         working_repo_dir, fix_filepaths, getRepoPath,
                      )
import Darcs.FilePathUtils ( just_dir )
import Darcs.RepoPath ( toFilePath )
import Darcs.Match ( get_nonrange_match_s, have_nonrange_match, apply_patches_to_some_files,
                   )
import Darcs.Repository ( withRepository, ($-), findRepository )
import Darcs.Repository ( createPartialsPristineDirectoryTree )
import Darcs.Lock ( withTempDir )
\end{code}

\options{show contents}
\begin{code}
show_contents_description :: String
show_contents_description = "Outputs a specific version of a file."
\end{code}
\haskell{show_contents_help}
\begin{code}
show_contents_help :: String
show_contents_help =
  "Show contents can be used to display an earlier version of some file(s).\n"++
  "If you give show contents no version arguments, it displays the recorded\n"++
  "version of the file(s).\n"

show_contents :: DarcsCommand
show_contents = DarcsCommand {command_name = "contents",
                              command_help = show_contents_help,
                              command_description = show_contents_description,
                              command_extra_args = -1,
                              command_extra_arg_help
                                    = ["[FILE]..."],
                              command_command = show_contents_cmd,
                              command_prereq = findRepository,
                              command_get_arg_possibilities = return [],
                              command_argdefaults = nodefaults,
                              command_advanced_options = [],
                              command_basic_options = [match_one, working_repo_dir]}
\end{code}

\begin{code}
show_contents_cmd :: [DarcsFlag] -> [String] -> IO ()
show_contents_cmd opts args = withRepository opts $- \repository -> do
  formerdir <- getCurrentDirectory
  thename <- return $ just_dir formerdir
  withTempDir thename $ \dir -> do
     if have_nonrange_match opts
        then withCurrentDirectory dir $
               apply_patches_to_some_files repository path_list $ get_nonrange_match_s opts
        else createPartialsPristineDirectoryTree repository path_list dir
     filterM doesFileExist path_list >>= mapM_ (\f -> readFilePS f >>= hPutPS stdout)
  where
    path_list = if null args then [""]
                   else map toFilePath $ getRepoPath $ fix_filepaths opts args
\end{code}