{-# LANGUAGE CPP #-}
{-|
Module : HsLua.Module.System
Copyright : © 2019-2026 Albert Krewinkel
License : MIT
Maintainer : Albert Krewinkel <tarleb@hslua.org>
Stability : alpha
Portability : Requires GHC 8 or later.
Provide a Lua module containing a selection of @'System'@ functions.
-}
module HsLua.Module.System (
-- * Module
documentedModule
-- ** Fields
, arch
, compiler_name
, compiler_version
, os
-- ** Functions
, cmd
, cp
, cputime
, env
, exists
, getenv
, getwd
, ls
, mkdir
, read_file
, rename
, rm
, rmdir
, setenv
, setwd
, times
, tmpdirname
, with_env
, with_tmpdir
, with_wd
, write_file
, xdg
)
where
import Control.Monad ((>=>), forM_)
import Control.Monad.Catch (bracket)
import Data.Maybe (fromMaybe)
import Data.Text (Text)
import Data.Version (versionBranch)
import HsLua.Core
import HsLua.List (newListMetatable)
import HsLua.Marshalling
import HsLua.Packaging
import HsLua.Module.SystemUtils
import qualified Data.ByteString as B
import qualified Data.Text as T
import qualified Data.Time as Time
import qualified Data.Time.Format.ISO8601 as ISO8601
import qualified HsLua.Core.Utf8 as Utf8
import qualified System.CPUTime as CPUTime
import qualified System.Directory as Directory
import qualified System.Environment as Env
import qualified System.Exit as Exit
import qualified System.Info as Info
import qualified System.IO.Temp as Temp
import qualified System.Process as Process
-- | The "system" module.
documentedModule :: LuaError e => Module e
documentedModule = defmodule "system"
`withFields`
[ arch
, compiler_name
, compiler_version
, cputime_precision
, os
]
`withFunctions`
[ cmd
, cp
, cputime
, env
, exists
, getenv
, getwd
, ls
, mkdir
, read_file
, rename
, rm
, rmdir
, setenv
, setwd
, times
, tmpdirname
, with_env
, with_tmpdir
, with_wd
, write_file
, xdg
]
`withDescription`
"Access to the system's information and file functionality."
--
-- Fields
--
-- | Module field containing the machine architecture on which the
-- program is running. Wraps @'Info.arch'@
arch :: Field e
arch = deffield "arch"
`withType`
stringType
`withDescription`
"The machine architecture on which the program is running."
`withValue`
pushString Info.arch
-- | Module field containing the Haskell implementation with which the
-- host program was compiled. Wraps @'Info.compilerName'@.
compiler_name :: Field e
compiler_name = deffield "compiler_name"
`withType`
stringType
`withDescription`
"The Haskell implementation with which the host program was compiled."
`withValue`
pushString Info.compilerName
-- | Module field containing the version of `compiler_name` with which
-- the host program was compiled.
compiler_version :: LuaError e => Field e
compiler_version = deffield "compiler_version"
`withType`
stringType
`withDescription`
"The Haskell implementation with which the host program was compiled."
`withValue`
pushList pushIntegral (versionBranch Info.compilerVersion)
-- | Field containing the smallest measurable difference in CPU time.
cputime_precision :: Field e
cputime_precision = deffield "cputime_precision"
`withType` integerType
`withDescription` T.unlines
[ "The smallest measurable difference in CPU time that the"
, "implementation can record, and is given as an integral number of"
, "picoseconds."
]
`withValue` pushIntegral CPUTime.cpuTimePrecision
-- | Field containing the operating system on which the program is
-- running.
os :: Field e
os = deffield "os"
`withType` "string"
`withDescription` T.unlines
[ "The operating system on which the program is running."
, "The most common values are `darwin` (macOS), `freebsd`, `linux`,"
, "`linux-android`, `mingw32` (Windows), `netbsd`, `openbsd`."
]
`withValue` pushString Info.os
--
-- Functions
--
-- | Run a system command
cmd :: LuaError e => DocumentedFunction e
cmd = defun "cmd"
### (\command args minput opts -> do
let input = fromMaybe "" minput
let cp_opts = (Process.proc command args)
{ Process.env = processOptsEnv =<< opts
, Process.cwd = processOptsCwd =<< opts
}
liftIO $ Process.readCreateProcessWithExitCode cp_opts input)
<#> filepathParam "command" "command to execute"
<#> parameter (peekList peekString) "{string,...}" "args" "command arguments"
<#> opt (parameter peekString "string" "input" "input on stdin")
<#> opt (parameter peekProcessOptions "table" "opts" "process options")
=#> (functionResult (pushExitCode . (\(a,_,_) -> a)) "integer|boolean"
"exit code – `false` on success, an integer otherwise" <>
functionResult (pushString . \(_,b,_) -> b) "string" "stdout" <>
functionResult (pushString . \(_,_,c) -> c) "string" "stderr")
#? T.unlines
[ "Executes a system command with the given arguments and `input`"
, "on *stdin*."
]
-- | Copy a file
cp :: LuaError e => DocumentedFunction e
cp = defun "cp"
### (\src tgt -> ioToLua $ Directory.copyFile src tgt)
<#> filepathParam "source" "source file"
<#> filepathParam "target" "target destination"
=#> []
#? T.unlines
[ "Copy a file with its permissions."
, "If the destination file already exists, it is overwritten."
]
-- | Access the CPU time, e.g. for benchmarking.
cputime :: LuaError e => DocumentedFunction e
cputime = defun "cputime"
### ioToLua CPUTime.getCPUTime
=#> functionResult pushIntegral "integer" "CPU time in picoseconds"
#? T.unlines
[ "Returns the number of picoseconds CPU time used by the current"
, "program. The precision of this result may vary in different"
, "versions and on different platforms."
]
-- | Retrieve the entire environment
env :: LuaError e => DocumentedFunction e
env = defun "env"
### ioToLua Env.getEnvironment
=#> functionResult (pushKeyValuePairs pushString pushString) "table"
"A table mapping environment variable names to their value."
#? "Retrieves the entire environment as a string-indexed table."
-- | Check the existence of a file path.
exists :: LuaError e => DocumentedFunction e
exists = defun "exists"
### (\fp mbType -> do
case T.toLower <$> mbType of
Nothing ->
-- any file type is fine
ioToLua $ Directory.doesPathExist fp
Just "directory" ->
-- must be a directory or a symlink pointing to one
ioToLua $ Directory.doesDirectoryExist fp
Just "file" ->
-- must be a file or a symlink pointing to one
ioToLua $ Directory.doesFileExist fp
Just "symlink" ->
-- must exist and be a symlink
ioToLua $ (&&) <$> Directory.doesPathExist fp
<*> Directory.pathIsSymbolicLink fp
Just otherType ->
failLua $
"Unsupported filesystem object type: " <> T.unpack otherType)
<#> filepathParam "path" "file path to check"
<#> opt (textParam "type" "the required type of the filesystem object")
=#> functionResult pushBool "boolean"
"whether a filesystem object of type `type` exists at `path`."
#? T.unlines
[ "Check whether there exists a filesystem object at the given path."
, "If `type` is given and either *directory* or *file*, then the"
, "function returns `true` if and only if the file system object has"
, "the given type, or if it's a symlink pointing to an object of that"
, "type. Passing *symlink* as type requires the path itself to be a"
, "symlink. Types other than those will cause an error."
]
-- | Return the current working directory as an absolute path.
getwd :: LuaError e => DocumentedFunction e
getwd = defun "getwd"
### ioToLua Directory.getCurrentDirectory
=#> filepathResult "The current working directory."
#? "Obtain the current working directory as an absolute path."
-- | Returns the value of an environment variable
getenv :: LuaError e => DocumentedFunction e
getenv = defun "getenv"
### ioToLua . Env.lookupEnv
<#> parameter peekString "string" "var" "name of the environment"
=#> functionResult (maybe pushnil pushString) "string or nil"
"value of the variable, or nil if the variable is not defined."
#? T.unwords
[ "Return the value of the environment variable `var`, or `nil` "
, "if there is no such value." ]
-- | List the contents of a directory.
ls :: LuaError e => DocumentedFunction e
ls = defun "ls"
### ioToLua . Directory.listDirectory . fromMaybe "."
<#> opt (stringParam "directory"
("Path of the directory whose contents should be listed. "
`T.append` "Defaults to `.`."))
=#> functionResult pushFilePathList "table"
("A table of all entries in `directory`, except for the "
`T.append` "special entries (`.` and `..`).")
#? "List the contents of a directory."
-- | Create a new directory which is initially empty, or as near to
-- empty as the operating system allows.
--
-- If the optional second parameter is `false`, then create the new
-- directory only if it doesn't exist yet. If the parameter is `true`,
-- then parent directories are created as necessary.
mkdir :: LuaError e => DocumentedFunction e
mkdir = defun "mkdir"
### (\fp createParent ->
if createParent == Just True
then ioToLua (Directory.createDirectoryIfMissing True fp)
else ioToLua (Directory.createDirectory fp))
<#> filepathParam "dirname" "name of the new directory"
<#> opt (boolParam "create_parent" "create parent directory if necessary")
=#> []
#? T.concat
[ "Create a new directory which is initially empty, or as near "
, "to empty as the operating system allows. The function throws "
, "an error if the directory cannot be created, e.g., if the "
, "parent directory does not exist or if a directory of the "
, "same name is already present.\n"
, "\n"
, "If the optional second parameter is provided and truthy, "
, "then all directories, including parent directories, are "
, "created as necessary.\n"
]
-- | Returns the contents of a file.
read_file :: LuaError e => DocumentedFunction e
read_file = defun "read_file"
### (ioToLua . B.readFile)
<#> filepathParam "filepath" "File to read"
=#> functionResult pushByteString "string" "file contents"
-- | Rename a file path.
rename :: LuaError e => DocumentedFunction e
rename = defun "rename"
### (\old new -> ioToLua $ do
isDir <- Directory.doesDirectoryExist old
if isDir
then Directory.renameDirectory old new
else Directory.renameFile old new)
<#> filepathParam "old" "original path"
<#> filepathParam "new" "new path"
=#> []
#? T.unlines
[ "Change the name of an existing path from `old` to `new`."
, ""
, "If `old` is a directory and `new` is a directory that already"
, "exists, then `new` is atomically replaced by the `old` directory."
, "On Win32 platforms, this function fails if `new` is an existing"
, "directory."
, ""
, "If `old` does not refer to a directory, then neither may `new`."
, ""
, "Renaming may not work across file system boundaries or due to"
, "other system-specific reasons. It's generally more robust to"
, "copy the source path to its destination before deleting the"
, "source."
]
-- | Remove a file.
rm :: LuaError e => DocumentedFunction e
rm = defun "rm"
### ioToLua . Directory.removeFile
<#> filepathParam "filename" "file to remove"
=#> []
#? "Removes the directory entry for an existing file."
-- | Remove an existing directory.
rmdir :: LuaError e => DocumentedFunction e
rmdir = defun "rmdir"
### (\fp recursive ->
if recursive == Just True
then ioToLua (Directory.removeDirectoryRecursive fp)
else ioToLua (Directory.removeDirectory fp))
<#> filepathParam "dirname" "name of the directory to delete"
<#> opt (boolParam "recursive" "delete content recursively")
=#> []
#?("Remove an existing, empty directory. If `recursive` is given, "
`T.append` "then delete the directory and its contents recursively.")
-- | Set the specified environment variable to a new value.
setenv :: LuaError e => DocumentedFunction e
setenv = defun "setenv"
### (\name value -> ioToLua (Env.setEnv name value))
<#> parameter peekString "string" "name"
"name of the environment variable"
<#> parameter peekString "string" "value" "new value"
=#> []
#? "Set the specified environment variable to a new value."
-- | Change current working directory.
setwd :: LuaError e => DocumentedFunction e
setwd = defun "setwd"
### ioToLua . Directory.setCurrentDirectory
<#> filepathParam "directory" "Path of the new working directory"
=#> []
#? "Change the working directory to the given path."
-- | Get the modification time and access time of a file.
times :: LuaError e => DocumentedFunction e
times = defun "times"
### (\filepath -> ioToLua $
(,) <$> Directory.getModificationTime filepath
<*> Directory.getAccessTime filepath)
<#> filepathParam "filepath" "file or directory path"
=#> (functionResult (pushUTCTime . fst) "table"
"time at which the file or directory was last modified" <>
functionResult (pushUTCTime . snd) "table"
"time at which the file or directory was last accessed")
#? T.unlines
[ "Obtain the modification and access time of a file or directory."
, "The times are returned as strings using the ISO 8601 format."
]
-- | Get the current directory for temporary files.
tmpdirname :: LuaError e => DocumentedFunction e
tmpdirname = defun "tmpdirname"
### ioToLua Directory.getTemporaryDirectory
=#> functionResult pushString "string"
"The current directory for temporary files."
#? mconcat
[ "Returns the current directory for temporary files.\n"
, "\n"
, "On Unix, `tmpdirname()` returns the value of the `TMPDIR` "
, "environment variable or \"/tmp\" if the variable isn't defined. "
, "On Windows, the function checks for the existence of environment "
, "variables in the following order and uses the first path found:\n"
, "\n"
, "- TMP environment variable.\n"
, "- TEMP environment variable.\n"
, "- USERPROFILE environment variable.\n"
, "- The Windows directory\n"
, "\n"
, "The operation may fail if the operating system has no notion of "
, "temporary directory.\n"
, "\n"
, "The function doesn't verify whether the path exists.\n"
]
-- | Run an action in a different directory, then restore the old
-- working directory.
with_wd :: LuaError e => DocumentedFunction e
with_wd = defun "with_wd"
### (\fp callback ->
bracket (ioToLua Directory.getCurrentDirectory)
(ioToLua . Directory.setCurrentDirectory)
(\_ -> do
ioToLua (Directory.setCurrentDirectory fp)
callback `invokeWithFilePath` fp))
<#> filepathParam "directory"
"Directory in which the given `callback` should be executed"
<#> parameter peekCallback "function" "callback"
"Action to execute in the given directory"
=?> "The results of the call to `callback`."
#? T.unwords
[ "Run an action within a different directory. This function will"
, "change the working directory to `directory`, execute `callback`,"
, "then switch back to the original working directory, even if an"
, "error occurs while running the callback action."
]
-- | Run an action, then restore the old environment variable values.
with_env :: LuaError e => DocumentedFunction e
with_env = defun "with_env"
### (\environment callback ->
bracket (ioToLua Env.getEnvironment)
setEnvironment
(\_ -> setEnvironment environment *> invoke callback))
<#> parameter (peekKeyValuePairs peekString peekString) "table"
"environment"
("Environment variables and their values to be set before "
`T.append` "running `callback`")
<#> parameter peekCallback "function" "callback"
"Action to execute in the custom environment"
=?> "The results of the call to `callback`."
#? T.unwords
[ "Run an action within a custom environment. Only the environment"
, "variables given by `environment` will be set, when `callback` is"
, "called. The original environment is restored after this function"
, "finishes, even if an error occurs while running the callback"
, "action."
]
where
setEnvironment newEnv = ioToLua $ do
-- Crude, but fast enough: delete all entries in new environment,
-- then restore old environment one-by-one.
curEnv <- Env.getEnvironment
forM_ curEnv (Env.unsetEnv . fst)
forM_ newEnv (uncurry Env.setEnv)
-- | Provides a temporary directory for the given action.
with_tmpdir :: LuaError e => DocumentedFunction e
with_tmpdir = defun "with_tmpdir"
### (\mParentDir tmpl callback -> case mParentDir of
Nothing -> do
Temp.withSystemTempDirectory tmpl $
invokeWithFilePath callback
Just parentDir -> do
Temp.withTempDirectory parentDir tmpl $
invokeWithFilePath callback)
<#> parameter peekParentDir "string" "parent_dir"
(mconcat
[ "Parent directory to create the directory in. If this "
, "parameter is omitted, the system's canonical temporary "
, "directory is used."
])
<#> stringParam "templ" "Directory name template."
<#> parameter peekCallback "function" "callback"
("Function which takes the name of the temporary directory as "
`T.append` "its first argument.")
=?> "The results of the call to `callback`."
#? T.unlines
[ "Create and use a temporary directory inside the given directory."
, "The directory is deleted after the callback returns."
]
where
peekParentDir idx = do
args <- liftLua gettop
if args < 3
then liftLua $ do
pushnil
insert idx
return Nothing
else Just <$> peekString idx
-- | Write a string to a file.
write_file :: LuaError e => DocumentedFunction e
write_file = defun "write_file"
### (\filepath contents ->
ioToLua $ B.writeFile filepath contents)
<#> filepathParam "filepath" "path to target file"
<#> parameter peekByteString "string" "contents" "file contents"
=#> []
#? "Writes a string to a file."
-- | Obtain the paths to special directories.
xdg :: LuaError e => DocumentedFunction e
xdg = defun "xdg"
### (\xdgDirTypeOrList mfp->
case xdgDirTypeOrList of
Left xdgDirType -> Left <$>
let fp = fromMaybe "" mfp
in ioToLua $ Directory.getXdgDirectory xdgDirType fp
Right xdgDirList ->
ioToLua $ Right <$> Directory.getXdgDirectoryList xdgDirList)
<#> parameter peekXdgDirectory "string" "xdg_directory_type"
(T.unlines
[ "The type of the XDG directory or search path."
, "Must be one of `config`, `data`, `cache`, `state`,"
, "`datadirs`, or `configdirs`."
, ""
, "Matching is case-insensitive, and underscores and `XDG`"
, "prefixes are ignored, so a value like"
, "`XDG_DATA_DIRS` is also acceptable."
, ""
, "The `state` directory might not be available, depending"
, "on the version of the underlying Haskell library."
])
<#> opt (filepathParam "filepath"
("relative path that is appended to the path; ignored " <>
"if the result is a list of search paths."))
=#> functionResult (either pushString pushFilePathList)
"string|{string,...}"
"Either a single file path, or a list of search paths."
#? T.unlines
[ "Access special directories and directory search paths."
, ""
, "Special directories for storing user-specific application"
, "data, configuration, and cache files, as specified by the"
, "[XDG Base Directory Specification](" <>
"https://specifications.freedesktop.org/basedir-spec/latest/)."
]
--
-- Parameters
--
-- | Filepath function parameter.
filepathParam :: Text -- ^ name
-> Text -- ^ description
-> Parameter e FilePath
filepathParam = stringParam
-- | Result of a function returning a file path.
filepathResult :: Text -- ^ Description
-> [FunctionResult e FilePath]
filepathResult = functionResult pushString "string"
--
-- Process parameters
--
-- | Process options
data ProcessOpts = ProcessOpts
{ processOptsEnv :: Maybe [(String, String)]
, processOptsCwd :: Maybe FilePath
}
-- | Peek process creation options
peekProcessOptions :: LuaError e => Peeker e ProcessOpts
peekProcessOptions = typeChecked "table" istable $ \idx -> do
let peekEnv = peekKeyValuePairs peekString peekString
env' <- peekFieldRaw (peekNilOr peekEnv) "env" idx
cwd' <- peekFieldRaw (peekNilOr peekString) "cwd" idx
return $ ProcessOpts
{ processOptsEnv = env'
, processOptsCwd = cwd'
}
-- | Pushes an exit code; failure codes are pushed as integers, and
-- success is pushed as `false`. This means that the value can be
-- interpreted as a boolean `failed` value.
pushExitCode :: Pusher e Exit.ExitCode
pushExitCode = \case
Exit.ExitSuccess -> pushBool False
Exit.ExitFailure n -> pushIntegral n
-- | Pushes a time as ISO 8601 string.
pushUTCTime :: Pusher e Time.UTCTime
pushUTCTime = pushString . ISO8601.iso8601Show
-- | Get an XDG directory type identifier.
peekXdgDirectory :: Peeker e
(Either Directory.XdgDirectory Directory.XdgDirectoryList)
peekXdgDirectory =
(fmap cleanupXdgSpec . peekText) >=> \case
"cache" -> pure (Left Directory.XdgCache)
"config" -> pure (Left Directory.XdgConfig)
"data" -> pure (Left Directory.XdgData)
#if MIN_VERSION_directory(1,3,7)
"state" -> pure (Left Directory.XdgState)
#endif
"datadirs" -> pure (Right Directory.XdgDataDirs)
"configdirs" -> pure (Right Directory.XdgConfigDirs)
s -> failPeek $
"Expected 'cache', 'config', 'data', or 'state', got: " <>
Utf8.fromText s
where
-- Cleanup the XDG directory specifier as to make matching easier
-- while keeping things permissive.
-- Remove underscores, any 'xdg' prefix, and
-- make sure everything is lowercase
cleanupXdgSpec =
(\s -> fromMaybe s $ T.stripPrefix "xdg" s)
. T.filter (/= '_')
. T.toLower
-- | Pushes a list of file paths.
pushFilePathList :: LuaError e => Pusher e [FilePath]
pushFilePathList fps = do
pushList pushString fps
newListMetatable "FilePath list" (pure ())
setmetatable (nth 2)