async versions of File.WriteAll*

File.AsyncWriteAllBytes
File.AsyncWriteAllText
File.AsyncWriteAllLines
example of use in AsyncFileExtensions.fsx
File.AppendAll* to follow

Author: Ian144

FSharpx.sln

@@ -16,6 +16,7 @@ Project("{F2A71F9B-5D33-465A-A702-920D77279786}") = "FSharpx.Core", "src\FSharpx
 EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Samples", "Samples", "{EFB3F0C2-10B4-4EF5-8FA7-CC39880067A1}"
 	ProjectSection(SolutionItems) = preProject
+		samples\AsyncFileExtensions.fsx = samples\AsyncFileExtensions.fsx
 		samples\AsyncSeqObservable.fsx = samples\AsyncSeqObservable.fsx
 		samples\AutoCancel.fsx = samples\AutoCancel.fsx
 		samples\BatchProcessing.fsx = samples\BatchProcessing.fsx

samples/AsyncFileExtensions.fsx

@@ -0,0 +1,30 @@
+
+
+//#r @"..\build\FSharpx.Core.dll"
+#r @"C:\Users\Ian\Documents\GitHub\Ian144\fsharpx\build\debug\FSharpx.Core.dll"
+
+open Microsoft.FSharp.Control
+
+
+let lines = [| for n in 1..100000 do
+               let str = sprintf "line: %d" n
+               yield str |]
+
+
+
+let asyncWriteA =  System.IO.File.AsyncWriteAllLines(@"c:\tmp\a.txt", lines)
+let asyncWriteB =  System.IO.File.AsyncWriteAllLines(@"c:\tmp\b.txt", lines)
+let asyncWriteC =  System.IO.File.AsyncWriteAllLines(@"c:\tmp\c.txt", lines)
+let asyncWriteD =  System.IO.File.AsyncWriteAllLines(@"c:\tmp\d.txt", lines)
+let asyncWriteE =  System.IO.File.AsyncWriteAllText( @"c:\tmp\e.txt", "this is some text")
+
+printfn "async write all lines begining"
+
+[|asyncWriteA; asyncWriteB; asyncWriteC; asyncWriteD; asyncWriteE|] 
+    |> Async.Parallel 
+    |> Async.RunSynchronously 
+    |> ignore
+
+
+
+printfn "async write all lines complete"

src/FSharpx.Core/AsyncOperations.fs

@@ -133,6 +133,47 @@ namespace Microsoft.FSharp.Control
                 System.IO.File.AsyncOpen(path, mode, ?access=access, ?share=share,?bufferSize=bufferSize,?options=options)
 #endif
 
+#if FX_NO_FILE_OPTIONS
+#else
+            // Aims to take advantage of IO completion ports using FileStream.AsyncWrite and FileOptions.Asynchronous, so no FX_NO_FILE_OPTIONS version
+            static member AsyncWriteAllBytes(path, bytes) =
+                let bufferSize = 4096 // as per File.WriteAllBytes
+                async{
+                    use! fs = System.IO.File.AsyncOpen( path, System.IO.FileMode.Create, System.IO.FileAccess.Write, System.IO.FileShare.Read, bufferSize, System.IO.FileOptions.Asynchronous)
+                    let! ret = fs.AsyncWrite bytes
+                    return ret
+                }
+
+            static member AsyncWriteAllText(path, (txt:string), ?encoder) =
+                let enc = match encoder with Some e -> e | None -> System.Text.Encoding.Default
+                async{
+                    let bs = enc.GetBytes txt
+                    return! System.IO.File.AsyncWriteAllBytes(path, bs)
+                }
+            
+            // Different memory profile to File.WriteAllLines, converts all lines to a byte[] before doing any writing, then a single write op.
+            // Not good for writing huge files, but writing one line at a time, as per File.WriteAllLines has its own issues, 
+            // e.g. sequential application of async IO (so lines are written in order)
+            static member AsyncWriteAllLines(path, (lines:string array), ?encoder) = 
+                let enc = match encoder with Some e -> e | None -> System.Text.Encoding.Default
+                async{
+                    use memStrm = new System.IO.MemoryStream()
+                    use sWriter = new System.IO.StreamWriter(memStrm, enc)
+                    lines |> Array.iter (fun line -> sWriter.WriteLine(line))
+                    do sWriter.Flush()
+                    let bs = memStrm.ToArray()
+                    return! System.IO.File.AsyncWriteAllBytes(path, bs)
+              }
+
+
+#endif
+
+
+
+
+
+
+
     [<AutoOpen>]
     module StreamReaderExtensions =
         type System.IO.StreamReader with

src/FSharpx.Core/AsyncOperations.fsi

@@ -62,6 +62,12 @@ namespace Microsoft.FSharp.Control
             static member AsyncOpen: path:string * mode:FileMode * ?access: FileAccess * ?share: FileShare * ?bufferSize: int -> Async<FileStream>
 #else
             static member AsyncOpen: path:string * mode:FileMode * ?access: FileAccess * ?share: FileShare * ?bufferSize: int * ?options: FileOptions -> Async<FileStream>
+
+            // Aims to take advantage of IO completion ports using FileStream.AsyncWrite and FileOptions.Asynchronous, so no FX_NO_FILE_OPTIONS version
+            static member AsyncWriteAllBytes: path:string * bytes:byte array -> Async<unit>
+
+            static member AsyncWriteAllText: path:string * txt:string * ?encoder:System.Text.Encoding -> Async<unit>
+            static member AsyncWriteAllLines: path:string * lines:string array * ?encoder:System.Text.Encoding -> Async<unit>
 #endif
 
 #if FX_NO_WEB_REQUESTS