git-annex/Annex/Path.hs
2020-08-26 12:29:13 -04:00

64 lines
1.9 KiB
Haskell

{- git-annex program path
-
- Copyright 2013-2020 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
module Annex.Path where
import Annex.Common
import Config.Files
import Utility.Env
import Annex.PidLock
import System.Environment (getExecutablePath)
{- A fully qualified path to the currently running git-annex program.
-
- getExecutablePath is used when possible. On OSs it supports
- well, it returns the complete path to the program. But, on other OSs,
- it might return just the basename. Fall back to reading the programFile,
- or searching for the command name in PATH.
-
- The standalone build runs git-annex via ld.so, and defeats
- getExecutablePath. It sets GIT_ANNEX_PROGRAMPATH to the correct path
- to the wrapper script to use.
-}
programPath :: IO FilePath
programPath = go =<< getEnv "GIT_ANNEX_PROGRAMPATH"
where
go (Just p) = return p
go Nothing = do
exe <- getExecutablePath
p <- if isAbsolute exe
then return exe
else fromMaybe exe <$> readProgramFile
maybe cannotFindProgram return =<< searchPath p
{- Returns the path for git-annex that is recorded in the programFile. -}
readProgramFile :: IO (Maybe FilePath)
readProgramFile = do
programfile <- programFile
headMaybe . lines <$> readFile programfile
cannotFindProgram :: IO a
cannotFindProgram = do
f <- programFile
giveup $ "cannot find git-annex program in PATH or in " ++ f
{- Runs a git-annex child process.
-
- Like runsGitAnnexChildProcessViaGit, when pid locking is in use,
- this takes the pid lock, while running it, and sets an env var
- that prevents the child process trying to take the pid lock,
- to avoid it deadlocking.
-}
gitAnnexChildProcess
:: [String]
-> (CreateProcess -> CreateProcess)
-> (Maybe Handle -> Maybe Handle -> Maybe Handle -> ProcessHandle -> IO a)
-> Annex a
gitAnnexChildProcess ps f a = do
cmd <- liftIO programPath
pidLockChildProcess cmd ps f a