Add file name to error message when reading a bad .gfo file (in some cases)

This turns error messages like 

	gf: too few bytes. Failed reading at byte position 1

	gf: /some/path/somefile.gfo: too few bytes. Failed reading at byte position 1

but a better fix would be to ignore bad .gfo files and compile from source.
The problem is the way this decision is made in
GF.Compile.ReadFiles.selectFormat...

1 files changed, 14 insertions, 3 deletions

diff --git a/src/compiler/GF/Grammar/Binary.hs b/src/compiler/GF/Grammar/Binary.hs
index f2653450f..ae0c72809 100644
--- a/src/compiler/GF/Grammar/Binary.hs
+++ b/src/compiler/GF/Grammar/Binary.hs
@@ -9,6 +9,9 @@
 

 module GF.Grammar.Binary where

 

+import Prelude hiding (catch)

+import Control.Exception(catch,ErrorCall(..),throwIO)

+

 import Data.Char

 import Data.Binary

 import Control.Monad

@@ -291,10 +294,9 @@ putGFOVersion = mapM_ (putWord8 . fromIntegral . ord) gfoVersion
 getGFOVersion = replicateM (length gfoVersion) (fmap (chr . fromIntegral) getWord8)

 

 decodeModule :: FilePath -> IO SourceModule

-decodeModule fpath =

-  decodeFile_ fpath (getGFOVersion >> get)

+decodeModule fpath = decodeFile' fpath (getGFOVersion >> get)

 

-decodeModuleHeader fpath = decodeFile_ fpath getVersionedMod

+decodeModuleHeader fpath = decodeFile' fpath getVersionedMod

   where

     getVersionedMod = do

       ver <- getGFOVersion

@@ -306,3 +308,12 @@ decodeModuleHeader fpath = decodeFile_ fpath getVersionedMod
 encodeModule :: FilePath -> SourceModule -> IO ()

 encodeModule fpath mo =

   encodeFile_ fpath (putGFOVersion >> put mo)

+

+-- | like decodeFile_ but adds file name to error message if there was an error

+decodeFile' fpath get = addFPath fpath (decodeFile_ fpath get)

+

+-- | Adds file name to error message if there was an error,

+-- | but laziness can cause errors to slip through

+addFPath fpath m = m `catch` handle

+  where

+    handle (ErrorCall msg) = throwIO (ErrorCall (fpath++": "++msg))