@@ -3,7 +3,7 @@
33{-# LANGUAGE OverloadedStrings #-}
44-- | This module uses template Haskell. Following is a simplified explanation of usage for those unfamiliar with calling Template Haskell functions.
55--
6−-- The function @embedFile@ in this modules embeds a file into the exceutable
6+-- The function @embedFile@ in this modules embeds a file into the executable
77-- that you can use it at runtime. A file is represented as a @ByteString@.
88-- However, as you can see below, the type signature indicates a value of type
99-- @Q Exp@ will be returned. In order to convert this into a @ByteString@, you
@@ -19,10 +19,16 @@
1919module Data.FileEmbed
2020 ( -- * Embed at compile time
2121 embedFile
22+ , embedFileIfExists
2223 , embedOneFileOf
2324 , embedDir
25+ , embedDirListing
2426 , getDir
27+ -- * Embed as a IsString
28+ , embedStringFile
29+ , embedOneStringFileOf
2530 -- * Inject into an executable
31+ -- $inject
2632#if MIN_VERSION_template_haskell(2,5,0)
2733 , dummySpace
2834 , dummySpaceWith
@@ -31,35 +37,45 @@ module Data.FileEmbed
3137 , injectFile
3238 , injectWith
3339 , injectFileWith
40+ -- * Relative path manipulation
41+ , makeRelativeToProject
42+ , makeRelativeToLocationPredicate
3443 -- * Internal
3544 , stringToBs
3645 , bsToExp
46+ , strToExp
3747 ) where
3848
3949import Language.Haskell.TH.Syntax
4050 ( Exp (AppE, ListE, LitE, TupE, SigE, VarE)
41−#if MIN_VERSION_template_haskell(2,5,0)
42− , Lit (StringL, StringPrimL, IntegerL)
43−#else
44− , Lit (StringL, IntegerL)
45−#endif
51+ , Lit (..)
4652 , Q
4753 , runIO
54+ , qLocation, loc_filename
4855#if MIN_VERSION_template_haskell(2,7,0)
4956 , Quasi(qAddDependentFile)
5057#endif
5158 )
59+#if MIN_VERSION_template_haskell(2,16,0)
60+import Language.Haskell.TH ( mkBytes, bytesPrimL )
61+import qualified Data.ByteString.Internal as B
62+#endif
5263import System.Directory (doesDirectoryExist, doesFileExist,
53− getDirectoryContents)
54−import Control.Exception (throw, ErrorCall(..))
55−import Control.Monad (filterM)
64+ getDirectoryContents, canonicalizePath)
65+import Control.Exception (throw, tryJust, ErrorCall(..))
66+import Control.Monad (filterM, guard)
5667import qualified Data.ByteString as B
5768import qualified Data.ByteString.Char8 as B8
5869import Control.Arrow ((&&&), second)
5970import Control.Applicative ((<$>))
6071import Data.ByteString.Unsafe (unsafePackAddressLen)
72+import System.IO.Error (isDoesNotExistError)
6173import System.IO.Unsafe (unsafePerformIO)
62−import System.FilePath ((</>))
74+import System.FilePath ((</>), takeDirectory, takeExtension)
75+import Data.String (fromString)
76+import Prelude as P
77+import Data.List (sortBy)
78+import Data.Ord (comparing)
6379
6480-- | Embed a single file in your source code.
6581--
@@ -74,13 +90,40 @@ embedFile fp =
7490#endif
7591 (runIO $ B.readFile fp) >>= bsToExp
7692
93+-- | Maybe embed a single file in your source code depending on whether or not file exists.
94+--
95+-- Warning: When a build is compiled with the file missing, a recompile when the file exists might not trigger an embed of the file.
96+-- You might try to fix this by doing a clean build.
97+--
98+-- > import qualified Data.ByteString
99+-- >
100+-- > maybeMyFile :: Maybe Data.ByteString.ByteString
101+-- > maybeMyFile = $(embedFileIfExists "dirName/fileName")
102+--
103+-- @since 0.0.14.0
104+embedFileIfExists :: FilePath -> Q Exp
105+embedFileIfExists fp = do
106+ mbs <- runIO maybeFile
107+ case mbs of
108+ Nothing -> [| Nothing |]
109+ Just bs -> do
110+#if MIN_VERSION_template_haskell(2,7,0)
111+ qAddDependentFile fp
112+#endif
113+ [| Just $(bsToExp bs) |]
114+ where
115+ maybeFile :: IO (Maybe B.ByteString)
116+ maybeFile =
117+ either (const Nothing) Just <$>
118+ tryJust (guard . isDoesNotExistError) (B.readFile fp)
119+
77120-- | Embed a single existing file in your source code
78121-- out of list a list of paths supplied.
79122--
80123-- > import qualified Data.ByteString
81124-- >
82125-- > myFile :: Data.ByteString.ByteString
83−-- > myFile = $(embedFile' [ "dirName/fileName", "src/dirName/fileName" ])
126+-- > myFile = $(embedOneFileOf [ "dirName/fileName", "src/dirName/fileName" ])
84127embedOneFileOf :: [FilePath] -> Q Exp
85128embedOneFileOf ps =
86129 (runIO $ readExistingFile ps) >>= \ ( path, content ) -> do
@@ -108,6 +151,18 @@ embedDir fp = do
108151 e <- ListE <$> ((runIO $ fileList fp) >>= mapM (pairToExp fp))
109152 return $ SigE e typ
110153
154+-- | Embed a directory listing recursively in your source code.
155+--
156+-- > myFiles :: [FilePath]
157+-- > myFiles = $(embedDirListing "dirName")
158+--
159+-- @since 0.0.11
160+embedDirListing :: FilePath -> Q Exp
161+embedDirListing fp = do
162+ typ <- [t| [FilePath] |]
163+ e <- ListE <$> ((runIO $ fmap fst <$> fileList fp) >>= mapM strToExp)
164+ return $ SigE e typ
165+
111166-- | Get a directory tree in the IO monad.
112167--
113168-- This is the workhorse of 'embedDir'
@@ -120,7 +175,11 @@ pairToExp _root (path, bs) = do
120175 qAddDependentFile $ _root ++ '/' : path
121176#endif
122177 exp' <- bsToExp bs
123− return $! TupE [LitE $ StringL path, exp']
178+ return $! TupE
179+#if MIN_VERSION_template_haskell(2,16,0)
180+ $ map Just
181+#endif
182+ [LitE $ StringL path, exp']
124183
125184bsToExp :: B.ByteString -> Q Exp
126185#if MIN_VERSION_template_haskell(2, 5, 0)
@@ -128,7 +187,11 @@ bsToExp bs =
128187 return $ VarE 'unsafePerformIO
129188 `AppE` (VarE 'unsafePackAddressLen
130189 `AppE` LitE (IntegerL $ fromIntegral $ B8.length bs)
131−#if MIN_VERSION_template_haskell(2, 8, 0)
190+#if MIN_VERSION_template_haskell(2, 16, 0)
191+ `AppE` LitE (bytesPrimL (
192+ let B.PS ptr off sz = bs
193+ in mkBytes ptr (fromIntegral off) (fromIntegral sz))))
194+#elif MIN_VERSION_template_haskell(2, 8, 0)
132195 `AppE` LitE (StringPrimL $ B.unpack bs))
133196#else
134197 `AppE` LitE (StringPrimL $ B8.unpack bs))
@@ -143,6 +206,51 @@ bsToExp bs = do
143206stringToBs :: String -> B.ByteString
144207stringToBs = B8.pack
145208
209+-- | Embed a single file in your source code.
210+--
211+-- > import Data.String
212+-- >
213+-- > myFile :: IsString a => a
214+-- > myFile = $(embedStringFile "dirName/fileName")
215+--
216+-- Since 0.0.9
217+embedStringFile :: FilePath -> Q Exp
218+embedStringFile fp =
219+#if MIN_VERSION_template_haskell(2,7,0)
220+ qAddDependentFile fp >>
221+#endif
222+ (runIO $ P.readFile fp) >>= strToExp
223+
224+-- | Embed a single existing string file in your source code
225+-- out of list a list of paths supplied.
226+--
227+-- Since 0.0.9
228+embedOneStringFileOf :: [FilePath] -> Q Exp
229+embedOneStringFileOf ps =
230+ (runIO $ readExistingFile ps) >>= \ ( path, content ) -> do
231+#if MIN_VERSION_template_haskell(2,7,0)
232+ qAddDependentFile path
233+#endif
234+ strToExp content
235+ where
236+ readExistingFile :: [FilePath] -> IO ( FilePath, String )
237+ readExistingFile xs = do
238+ ys <- filterM doesFileExist xs
239+ case ys of
240+ (p:_) -> P.readFile p >>= \ c -> return ( p, c )
241+ _ -> throw $ ErrorCall "Cannot find file to embed as resource"
242+
243+strToExp :: String -> Q Exp
244+#if MIN_VERSION_template_haskell(2, 5, 0)
245+strToExp s =
246+ return $ VarE 'fromString
247+ `AppE` LitE (StringL s)
248+#else
249+strToExp s = do
250+ helper <- [| fromString |]
251+ return $! AppE helper $! LitE $! StringL s
252+#endif
253+
146254notHidden :: FilePath -> Bool
147255notHidden ('.':_) = False
148256notHidden _ = True
@@ -158,7 +266,7 @@ fileList' realTop top = do
158266 mapM (liftPair2 . second B.readFile)
159267 dirs <- filterM (doesDirectoryExist . snd) all' >>=
160268 mapM (fileList' realTop . fst)
161− return $ concat $ files : dirs
269+ return $ sortBy (comparing fst) $ concat $ files : dirs
162270
163271liftPair2 :: Monad m => (a, m b) -> m (a, b)
164272liftPair2 (a, b) = b >>= \b' -> return (a, b')
@@ -182,6 +290,8 @@ padSize i =
182290 in replicate (sizeLen - length s) '0' ++ s
183291
184292#if MIN_VERSION_template_haskell(2,5,0)
293+-- | Allocate the given number of bytes in the generate executable. That space
294+-- can be filled up with the 'inject' and 'injectFile' functions.
185295dummySpace :: Int -> Q Exp
186296dummySpace = dummySpaceWith "MS"
187297
@@ -189,6 +299,8 @@ dummySpace = dummySpaceWith "MS"
189299-- order for this to work, the same postfix must be used by 'inject' /
190300-- 'injectFile'. This allows an executable to have multiple
191301-- 'ByteString's injected into it, without encountering collisions.
302+--
303+-- Since 0.0.8
192304dummySpaceWith :: B.ByteString -> Int -> Q Exp
193305dummySpaceWith postfix space = do
194306 let size = padSize space
@@ -204,12 +316,17 @@ dummySpaceWith postfix space = do
204316 [| getInner (B.drop magicLen (unsafePerformIO (unsafePackAddressLen len $(return chars)))) |]
205317#endif
206318
319+-- | Inject some raw data inside a @ByteString@ containing empty, dummy space
320+-- (allocated with @dummySpace@). Typically, the original @ByteString@ is an
321+-- executable read from the filesystem.
207322inject :: B.ByteString -- ^ bs to inject
208323 -> B.ByteString -- ^ original BS containing dummy
209324 -> Maybe B.ByteString -- ^ new BS, or Nothing if there is insufficient dummy space
210325inject = injectWith "MS"
211326
212327-- | Like 'inject', but takes a postfix for the magic string.
328+--
329+-- Since 0.0.8
213330injectWith :: B.ByteString -- ^ postfix of magic string
214331 -> B.ByteString -- ^ bs to inject
215332 -> B.ByteString -- ^ original BS containing dummy
@@ -228,6 +345,9 @@ injectWith postfix toInj orig =
228345 [] -> error $ "Data.FileEmbed (inject): Your dummy space has been corrupted. Size is: " ++ show sizeBS
229346 after = B.drop size rest'
230347
348+-- | Same as 'inject', but instead of performing the injecting in memory, read
349+-- the contents from the filesystem and write back to a different file on the
350+-- filesystem.
231351injectFile :: B.ByteString -- ^ bs to inject
232352 -> FilePath -- ^ template file
233353 -> FilePath -- ^ output file
@@ -235,6 +355,8 @@ injectFile :: B.ByteString -- ^ bs to inject
235355injectFile = injectFileWith "MS"
236356
237357-- | Like 'injectFile', but takes a postfix for the magic string.
358+--
359+-- Since 0.0.8
238360injectFileWith :: B.ByteString -- ^ postfix of magic string
239361 -> B.ByteString -- ^ bs to inject
240362 -> FilePath -- ^ template file
@@ -245,3 +367,75 @@ injectFileWith postfix inj srcFP dstFP = do
245367 case injectWith postfix inj src of
246368 Nothing -> error "Insufficient dummy space"
247369 Just dst -> B.writeFile dstFP dst
370+
371+{- $inject
372+
373+The inject system allows arbitrary content to be embedded inside a Haskell
374+executable, post compilation. Typically, file-embed allows you to read some
375+contents from the file system at compile time and embed them inside your
376+executable. Consider a case, instead, where you would want to embed these
377+contents after compilation. Two real-world examples are:
378+
379+* You would like to embed a hash of the executable itself, for sanity checking in a network protocol. (Obviously the hash will change after you embed the hash.)
380+
381+* You want to create a self-contained web server that has a set of content, but will need to update the content on machines that do not have access to GHC.
382+
383+The typical workflow use:
384+
385+* Use 'dummySpace' or 'dummySpaceWith' to create some empty space in your executable
386+
387+* Use 'injectFile' or 'injectFileWith' from a separate utility to modify that executable to have the updated content.
388+
389+The reason for the @With@-variant of the functions is for cases where you wish
390+to inject multiple different kinds of content, and therefore need control over
391+the magic key. If you know for certain that there will only be one dummy space
392+available, you can use the non-@With@ variants.
393+
394+-}
395+
396+-- | Take a relative file path and attach it to the root of the current
397+-- project.
398+--
399+-- The idea here is that, when building with Stack, the build will always be
400+-- executed with a current working directory of the root of the project (where
401+-- your .cabal file is located). However, if you load up multiple projects with
402+-- @stack ghci@, the working directory may be something else entirely.
403+--
404+-- This function looks at the source location of the Haskell file calling it,
405+-- finds the first parent directory with a .cabal file, and uses that as the
406+-- root directory for fixing the relative path.
407+--
408+-- @$(makeRelativeToProject "data/foo.txt" >>= embedFile)@
409+--
410+-- @since 0.0.10
411+makeRelativeToProject :: FilePath -> Q FilePath
412+makeRelativeToProject = makeRelativeToLocationPredicate $ (==) ".cabal" . takeExtension
413+
414+-- | Take a predicate to infer the project root and a relative file path, the given file path is then attached to the inferred project root
415+--
416+-- This function looks at the source location of the Haskell file calling it,
417+-- finds the first parent directory with a file matching the given predicate, and uses that as the
418+-- root directory for fixing the relative path.
419+--
420+-- @$(makeRelativeToLocationPredicate ((==) ".cabal" . takeExtension) "data/foo.txt" >>= embedFile)@
421+--
422+-- @since 0.0.15.0
423+makeRelativeToLocationPredicate :: (FilePath -> Bool) -> FilePath -> Q FilePath
424+makeRelativeToLocationPredicate isTargetFile rel = do
425+ loc <- qLocation
426+ runIO $ do
427+ srcFP <- canonicalizePath $ loc_filename loc
428+ mdir <- findProjectDir srcFP
429+ case mdir of
430+ Nothing -> error $ "Could not find .cabal file for path: " ++ srcFP
431+ Just dir -> return $ dir </> rel
432+ where
433+ findProjectDir x = do
434+ let dir = takeDirectory x
435+ if dir == x
436+ then return Nothing
437+ else do
438+ contents <- getDirectoryContents dir
439+ if any isTargetFile contents
440+ then return (Just dir)
441+ else findProjectDir dir