feat(journal): Make own version of fileAllocate that works on Mac OS

src/journal/cbits/mac_falloc.c

@@ -0,0 +1,25 @@
+#include <fcntl.h>
+#include <unistd.h>
+
+// based on https://github.com/coilhq/tigerbeetle/blob/7e12fccc4859f035cd26af29b8e9f9749a0899a3/src/storage.zig#L430
+int mac_fallocate(int fd, off_t offset, off_t length) {
+  fstore_t store = {
+    .fst_flags = F_ALLOCATECONTIG | F_ALLOCATEALL,
+    .fst_posmode = F_PEOFPOSMODE,
+    .fst_offset = 0,
+    .fst_length = offset + length,
+    .fst_bytesalloc = 0,
+  };
+
+  int res = fcntl(fd, F_PREALLOCATE, &store);
+  if (res != 0) {
+    store.fst_flags = F_ALLOCATEALL;
+    res = fcntl(fd, F_PREALLOCATE, &store);
+  }
+
+  if (res != 0) {
+    return res;
+  }
+
+  return ftruncate(fd, length);
+}

src/journal/journal.cabal

@@ -23,9 +23,14 @@ extra-source-files:
   LICENSE
   README.md
   cbits/atomic.c
+  cbits/mac_falloc.c
 
 library
-  hs-source-dirs:   src/
+  hs-source-dirs:   src
+  if os(darwin)
+    hs-source-dirs: osx
+  if os(linux)
+    hs-source-dirs: linux
 
   -- GHC boot library dependencies:
   -- (https://gitlab.haskell.org/ghc/ghc/-/blob/master/packages)
@@ -49,6 +54,7 @@ library
     Journal.CRC32
     Journal.Internal
     Journal.Internal.Atomics
+    Journal.Internal.FileAllocate
     Journal.Internal.Parse
     Journal.Internal.Metrics
     Journal.Internal.ByteBuffer
@@ -62,7 +68,10 @@ library
   ghc-options:      -O2
   if os(linux)
     extra-libraries: atomic
-  c-sources:        cbits/atomic.c
+  c-sources:
+    cbits/atomic.c
+  if os(darwin)
+    c-sources: cbits/mac_falloc.c
   default-language: Haskell2010
 
 test-suite test

src/journal/linux/Journal/Internal/FileAllocate.hs

@@ -0,0 +1,12 @@
+module Journal.Internal.FileAllocate
+  (fileAllocate)
+  where
+
+import Foreign
+import Foreign.C.Types
+
+import System.Posix.Types
+import qualified System.Posix.Fcntl as Posix
+
+fileAllocate :: Fd -> FileOffset -> FileOffset -> IO ()
+fileAllocate = Posix.fileAllocate

src/journal/osx/Journal/Internal/FileAllocate.hs

@@ -0,0 +1,20 @@
+{-# LANGUAGE ForeignFunctionInterface #-}
+module Journal.Internal.FileAllocate
+  (fileAllocate)
+  where
+
+import Foreign
+import Foreign.C.Types
+
+import System.Posix.Types
+
+foreign import ccall unsafe "mac_fallocate"
+  mac_fallocate :: CInt -> COff -> COff -> IO Int
+
+fileAllocate :: Fd -> FileOffset -> FileOffset -> IO ()
+fileAllocate fd off len = do
+  res <- mac_fallocate (fromIntegral fd) off len
+  if res == 0
+    then return ()
+    else error $ "fileAllocate " <> show fd <> " " <> show off <> " " <> show len
+                <> " ;;; returned returned non-zero result: " <> show res

src/journal/src/Journal.hs

@@ -35,12 +35,12 @@ import System.Directory
        , getFileSize
        )
 import System.FilePath (takeDirectory, (</>))
-import System.Posix.Fcntl (fileAllocate)
 import System.Posix.IO (fdWriteBuf)
 
 import Journal.Internal
 import Journal.Internal.BufferClaim
 import Journal.Internal.ByteBufferPtr
+import Journal.Internal.FileAllocate (fileAllocate)
 import Journal.Internal.Mmap (sysconfPageSize)
 import Journal.Types
 import Journal.Types.AtomicCounter