diff --git a/atomic-write.cabal b/atomic-write.cabal --- a/atomic-write.cabal +++ b/atomic-write.cabal @@ -1,5 +1,5 @@ name: atomic-write -version: 0.1.0.1 +version: 0.2.0.0 synopsis: Atomically write to a file description: @@ -30,8 +30,18 @@ . * . - Note that at this time Windows is not supported, however we would appreciate + At this time Windows is not supported, however we would appreciate contributions to the . + . + To use `atomic-write`, import the module corresponding to the type you wish to + write atomically, e.g., to write a (strict) ByteString atomically: + . + > import System.AtomicWrite.Writer.ByteString + . + Then you can use the atomicWrite function that accepts a `FilePath` and a + `ByteString`, e.g.: + . + > atomicWrite myFilePath myByteString license: MIT license-file: LICENSE author: Justin Leitgeb @@ -39,18 +49,24 @@ copyright: 2015 Stack Builders Inc. category: System build-type: Simple --- extra-source-files: cabal-version: >=1.10 library - exposed-modules: System.AtomicWrite - -- other-modules: - -- other-extensions: + exposed-modules: System.AtomicWrite.Writer.ByteString + , System.AtomicWrite.Writer.ByteStringBuilder + , System.AtomicWrite.Writer.LazyByteString + , System.AtomicWrite.Writer.String + , System.AtomicWrite.Writer.Text + + other-modules: System.AtomicWrite.Internal + build-depends: base >=4.5 && <4.8 , temporary , unix , directory , filepath + , text + , bytestring >= 0.10.4 hs-source-dirs: src default-language: Haskell2010 @@ -66,6 +82,8 @@ , unix , directory , filepath + , text + , bytestring >= 0.10.4 , hspec diff --git a/src/System/AtomicWrite.hs b/src/System/AtomicWrite.hs deleted file mode 100644 --- a/src/System/AtomicWrite.hs +++ /dev/null @@ -1,63 +0,0 @@ --- | --- Module : System.AtomicWrite --- Copyright : (c) 2015 Stack Builders Inc. --- --- License : MIT --- Maintainer : justin@stackbuilders.com --- Stability : experimental --- Portability : GHC --- --- A library for atomically modifying files while preserving permissions --- - -module System.AtomicWrite (atomicWriteFile) where - -import System.Directory (renameFile, doesFileExist) -import System.FilePath.Posix (takeDirectory) -import System.IO - (Handle, openTempFile, openTempFileWithDefaultPermissions, hPutStr, hClose) - -import System.Posix.Files (setFileMode, getFileStatus, fileMode) - - --- | Creates a file atomically on POSIX-compliant systems while preserving --- permissions. -atomicWriteFile :: - FilePath -- ^ The path where the file will be updated or created - -> String -- ^ The content to write to the file - -> IO () -atomicWriteFile f txt = do - (temppath, h) <- tempFileFor f - - hPutStr h txt - hClose h - - renameFile temppath f - - --- | Returns a temporary file with permissions correctly set. chooses --- either previously-set permissions if the file that we're writing --- to existed, or permissions following the current umask. -tempFileFor :: FilePath -> IO (FilePath, Handle) -tempFileFor originalFilePath = do - let targetDirectory = takeDirectory originalFilePath - - doesFileExist originalFilePath >>= - tmpFile originalFilePath targetDirectory "atomic.write" - - where - - tmpFile :: FilePath -> FilePath -> String -> Bool -> IO (FilePath, Handle) - tmpFile originalPath workingDirectory template previousExisted = - - if previousExisted then do - (temppath, handle) <- openTempFile workingDirectory template - - oldStat <- getFileStatus originalPath - - setFileMode temppath $ fileMode oldStat - - return (temppath, handle) - - else - openTempFileWithDefaultPermissions workingDirectory template diff --git a/src/System/AtomicWrite/Internal.hs b/src/System/AtomicWrite/Internal.hs new file mode 100644 --- /dev/null +++ b/src/System/AtomicWrite/Internal.hs @@ -0,0 +1,41 @@ +module System.AtomicWrite.Internal (closeAndRename, tempFileFor) where + +import System.Directory (doesFileExist, renameFile) +import System.Posix.Files (setFileMode, getFileStatus, fileMode) +import System.FilePath.Posix (takeDirectory) + +import System.IO + (hClose, Handle, openTempFile, openTempFileWithDefaultPermissions) + +-- | Returns a temporary file with permissions correctly set. Chooses +-- either previously-set permissions if the file that we're writing +-- to existed, or permissions following the current umask. +tempFileFor :: + FilePath -- ^ The target filepath that we will replace atomically. + -> IO (FilePath, Handle) +tempFileFor targetFilePath = + + doesFileExist targetFilePath >>= + tmpFile targetFilePath (takeDirectory targetFilePath) "atomic.write" + + where + + tmpFile :: FilePath -> FilePath -> String -> Bool -> IO (FilePath, Handle) + tmpFile targetPath workingDirectory template previousExisted = + + if previousExisted then + openTempFile workingDirectory template >>= + + \(tmpPath, handle) -> + + getFileStatus targetPath >>= setFileMode tmpPath . fileMode >> + + return (tmpPath, handle) + + else + openTempFileWithDefaultPermissions workingDirectory template + + +closeAndRename :: Handle -> FilePath -> FilePath -> IO () +closeAndRename tmpHandle tempFile destFile = + hClose tmpHandle >> renameFile tempFile destFile diff --git a/src/System/AtomicWrite/Writer/ByteString.hs b/src/System/AtomicWrite/Writer/ByteString.hs new file mode 100644 --- /dev/null +++ b/src/System/AtomicWrite/Writer/ByteString.hs @@ -0,0 +1,14 @@ +module System.AtomicWrite.Writer.ByteString (atomicWriteFile) where + +import System.AtomicWrite.Internal (closeAndRename, tempFileFor) + +import Data.ByteString (ByteString, hPutStr) + +-- | Creates a file atomically on POSIX-compliant systems while preserving +-- permissions. +atomicWriteFile :: + FilePath -- ^ The path where the file will be updated or created + -> ByteString -- ^ The content to write to the file + -> IO () +atomicWriteFile f txt = + tempFileFor f >>= \(tmpPath, h) -> hPutStr h txt >> closeAndRename h tmpPath f diff --git a/src/System/AtomicWrite/Writer/ByteStringBuilder.hs b/src/System/AtomicWrite/Writer/ByteStringBuilder.hs new file mode 100644 --- /dev/null +++ b/src/System/AtomicWrite/Writer/ByteStringBuilder.hs @@ -0,0 +1,26 @@ +module System.AtomicWrite.Writer.ByteStringBuilder (atomicWriteFile) where + +import System.AtomicWrite.Internal (closeAndRename, tempFileFor) + +import Data.ByteString.Builder (hPutBuilder, Builder, hPutBuilder) + +import GHC.IO.Handle (hSetBinaryMode, hSetBuffering, BufferMode (BlockBuffering)) + +-- | Creates a file atomically on POSIX-compliant systems while preserving +-- permissions. +atomicWriteFile :: + FilePath -- ^ The path where the file will be updated or created + -> Builder -- ^ The content to write to the file + -> IO () +atomicWriteFile f builder = do + (temppath, h) <- tempFileFor f + + -- Recommendations for binary and buffering are from the + -- Data.ByteString.Builder docs: + -- http://hackage.haskell.org/package/bytestring-0.10.2.0/docs/Data-ByteString-Builder.html#v:hPutBuilder + hSetBinaryMode h True + hSetBuffering h (BlockBuffering Nothing) + + hPutBuilder h builder + + closeAndRename h temppath f diff --git a/src/System/AtomicWrite/Writer/LazyByteString.hs b/src/System/AtomicWrite/Writer/LazyByteString.hs new file mode 100644 --- /dev/null +++ b/src/System/AtomicWrite/Writer/LazyByteString.hs @@ -0,0 +1,14 @@ +module System.AtomicWrite.Writer.LazyByteString (atomicWriteFile) where + +import System.AtomicWrite.Internal (closeAndRename, tempFileFor) + +import Data.ByteString.Lazy (ByteString, hPutStr) + +-- | Creates a file atomically on POSIX-compliant systems while preserving +-- permissions. +atomicWriteFile :: + FilePath -- ^ The path where the file will be updated or created + -> ByteString -- ^ The content to write to the file + -> IO () +atomicWriteFile f txt = + tempFileFor f >>= \(tmpPath, h) -> hPutStr h txt >> closeAndRename h tmpPath f diff --git a/src/System/AtomicWrite/Writer/String.hs b/src/System/AtomicWrite/Writer/String.hs new file mode 100644 --- /dev/null +++ b/src/System/AtomicWrite/Writer/String.hs @@ -0,0 +1,14 @@ +module System.AtomicWrite.Writer.String (atomicWriteFile) where + +import System.AtomicWrite.Internal (closeAndRename, tempFileFor) + +import System.IO (hPutStr) + +-- | Creates a file atomically on POSIX-compliant systems while preserving +-- permissions. +atomicWriteFile :: + FilePath -- ^ The path where the file will be updated or created + -> String -- ^ The content to write to the file + -> IO () +atomicWriteFile f txt = + tempFileFor f >>= \(tmpPath, h) -> hPutStr h txt >> closeAndRename h tmpPath f diff --git a/src/System/AtomicWrite/Writer/Text.hs b/src/System/AtomicWrite/Writer/Text.hs new file mode 100644 --- /dev/null +++ b/src/System/AtomicWrite/Writer/Text.hs @@ -0,0 +1,16 @@ +module System.AtomicWrite.Writer.Text (atomicWriteFile) where + +import System.AtomicWrite.Internal (closeAndRename, tempFileFor) + +import Data.Text (Text) + +import Data.Text.IO (hPutStr) + +-- | Creates a file atomically on POSIX-compliant systems while preserving +-- permissions. +atomicWriteFile :: + FilePath -- ^ The path where the file will be updated or created + -> Text -- ^ The content to write to the file + -> IO () +atomicWriteFile f txt = + tempFileFor f >>= \(tmpPath, h) -> hPutStr h txt >> closeAndRename h tmpPath f