Create an API layer for external process

Directory.Packages.props

@@ -23,7 +23,9 @@
     <PackageVersion Include="Microsoft.SourceLink.GitHub" Version="8.0.0" />
     <PackageVersion Include="NUnit" Version="3.14.0" />
     <PackageVersion Include="NUnit3TestAdapter" Version="5.0.0" />
+    <PackageVersion Include="SemanticVersioning" Version="2.0.2" />
+    <PackageVersion Include="StreamJsonRpc" Version="2.8.28" />
     <PackageVersion Include="System.Reactive" Version="6.0.1" />
     <PackageVersion Include="System.Text.Json" Version="9.0.0" />
   </ItemGroup>
-</Project>
+</Project>

FSharpLint.slnx

@@ -97,10 +97,12 @@
   </Folder>
   <Folder Name="/src/">
     <Project Path="src/FSharpLint.Console/FSharpLint.Console.fsproj" />
+    <Project Path="src/FSharpLint.Client/FSharpLint.Client.fsproj" />
     <Project Path="src/FSharpLint.Core/FSharpLint.Core.fsproj" />
   </Folder>
   <Folder Name="/tests/">
     <Project Path="tests/FSharpLint.Benchmarks/FSharpLint.Benchmarks.fsproj" />
+    <Project Path="tests/FSharpLint.Client.Tests/FSharpLint.Client.Tests.fsproj" />
     <Project Path="tests/FSharpLint.Console.Tests/FSharpLint.Console.Tests.fsproj" />
     <Project Path="tests/FSharpLint.Core.Tests/FSharpLint.Core.Tests.fsproj" />
     <Project Path="tests/FSharpLint.FunctionalTest/FSharpLint.FunctionalTest.fsproj" />

src/FSharpLint.Client/Contracts.fs

@@ -0,0 +1,31 @@
+module FSharpLint.Client.Contracts
+
+open System
+open System.Threading
+open System.Threading.Tasks
+
+[<RequireQualifiedAccess>]
+module Methods =
+    [<Literal>]
+    let Version = "fsharplint/version"
+
+type VersionRequest =
+    {
+        FilePath: string
+    }
+
+type FSharpLintResult =
+    | Content of string
+
+type FSharpLintResponse = { 
+    Code: int
+    FilePath: string
+    Result : FSharpLintResult
+}
+
+type IFSharpLintService =
+    interface
+        inherit IDisposable
+
+        abstract member VersionAsync: VersionRequest * ?cancellationToken: CancellationToken -> Task<FSharpLintResponse>
+    end

src/FSharpLint.Client/Contracts.fsi

@@ -0,0 +1,28 @@
+module FSharpLint.Client.Contracts
+
+open System.Threading
+open System.Threading.Tasks
+
+module Methods =
+
+    [<Literal>]
+    val Version: string = "fsharplint/version"
+
+type VersionRequest =
+    {
+        FilePath: string
+    }
+
+type FSharpLintResult =
+    | Content of string
+
+type FSharpLintResponse = { 
+    Code: int
+    FilePath: string
+    Result : FSharpLintResult
+}
+
+type IFSharpLintService =
+    inherit System.IDisposable
+
+    abstract VersionAsync: VersionRequest * ?cancellationToken: CancellationToken -> Task<FSharpLintResponse>

src/FSharpLint.Client/FSharpLint.Client.fsproj

@@ -0,0 +1,36 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFrameworks>net9.0;net8.0</TargetFrameworks>
+    <GenerateDocumentationFile>true</GenerateDocumentationFile>
+    <IsPackable>true</IsPackable>
+    <RootNamespace>FSharpLint.Client</RootNamespace>
+    <EnableDefaultItems>false</EnableDefaultItems>
+    <Title>FSharpLint.Client</Title>
+    <Description>Companion library to format using FSharpLint tool.</Description>
+    <PackageTags>F#;fsharp;lint;FSharpLint;fslint;api</PackageTags>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <Compile Include="Contracts.fsi" />
+    <Compile Include="Contracts.fs" />
+    <Compile Include="LSPFSharpLintServiceTypes.fsi" />
+    <Compile Include="LSPFSharpLintServiceTypes.fs" />
+    <Compile Include="FSharpLintToolLocator.fsi" />
+    <Compile Include="FSharpLintToolLocator.fs" />
+    <Compile Include="LSPFSharpLintService.fsi" />
+    <Compile Include="LSPFSharpLintService.fs" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\FSharpLint.Core\FSharpLint.Core.fsproj" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <PackageReference Include="FSharp.Core" />
+    <PackageReference Include="SemanticVersioning" />
+    <PackageReference Include="StreamJsonRpc" />
+    <PackageReference Include="System.Text.Json" />
+  </ItemGroup>
+
+</Project>

src/FSharpLint.Client/FSharpLintToolLocator.fs

@@ -0,0 +1,254 @@
+module FSharpLint.Client.FSharpLintToolLocator
+
+open System
+open System.ComponentModel
+open System.Diagnostics
+open System.IO
+open System.Text.RegularExpressions
+open System.Runtime.InteropServices
+open StreamJsonRpc
+open FSharpLint.Client.LSPFSharpLintServiceTypes
+
+let private supportedRange = SemanticVersioning.Range(">=v0.21.3") //TODO: proper version
+
+let private (|CompatibleVersion|_|) (version: string) =
+    match SemanticVersioning.Version.TryParse version with
+    | true, parsedVersion ->
+        if supportedRange.IsSatisfied(parsedVersion, includePrerelease = true) then
+            Some version
+        else
+            None
+    | _ -> None
+let [<Literal>] FSharpLintToolName = "dotnet-fsharplint"
+
+let private (|CompatibleToolName|_|) toolName =
+    if toolName = FSharpLintToolName then
+        Some toolName
+    else
+        None
+
+let private readOutputStreamAsLines (outputStream: StreamReader) : string list =
+    let rec readLines (outputStream: StreamReader) (continuation: string list -> string list) =
+        let nextLine = outputStream.ReadLine()
+
+        if isNull nextLine then
+            continuation List.Empty
+        else
+            readLines outputStream (fun lines -> nextLine :: lines |> continuation)
+
+    readLines outputStream id
+
+let private startProcess (ps: ProcessStartInfo) : Result<Process, ProcessStartError> =
+    try
+        Ok(Process.Start ps)
+    with
+    | :? Win32Exception as win32ex ->
+        let pathEnv = Environment.GetEnvironmentVariable "PATH"
+
+        Error(
+            ProcessStartError.ExecutableFileNotFound(
+                ps.FileName,
+                ps.Arguments,
+                ps.WorkingDirectory,
+                pathEnv,
+                win32ex.Message
+            )
+        )
+    | ex -> Error(ProcessStartError.UnexpectedException(ps.FileName, ps.Arguments, ex.Message))
+
+let private runToolListCmd (workingDir: Folder) (globalFlag: bool) : Result<string list, DotNetToolListError> =
+    let ps = ProcessStartInfo("dotnet")
+    ps.WorkingDirectory <- Folder.Unwrap workingDir
+    ps.EnvironmentVariables.["DOTNET_CLI_UI_LANGUAGE"] <- "en-us" //ensure we have predictible output for parsing
+
+    let toolArguments =
+        Option.ofObj (Environment.GetEnvironmentVariable "FSHARPLINT_SEARCH_PATH_OVERRIDE")
+        |> Option.map(fun env -> $" --tool-path %s{env}")
+        |> Option.defaultValue (if globalFlag then "--global" else String.Empty)
+
+    ps.CreateNoWindow <- true
+    ps.Arguments <- $"tool list %s{toolArguments}"
+    ps.RedirectStandardOutput <- true
+    ps.RedirectStandardError <- true
+    ps.UseShellExecute <- false
+
+    match startProcess ps with
+    | Ok proc ->
+        proc.WaitForExit()
+        let exitCode = proc.ExitCode
+
+        if exitCode = 0 then
+            let output = readOutputStreamAsLines proc.StandardOutput
+            Ok output
+        else
+            let error = proc.StandardError.ReadToEnd()
+            Error(DotNetToolListError.ExitCodeNonZero(ps.FileName, ps.Arguments, exitCode, error))
+    | Error err -> Error(DotNetToolListError.ProcessStartError err)
+
+let private (|CompatibleTool|_|) lines =
+    let (|HeaderLine|_|) (line: String) =
+        if Regex.IsMatch(line, @"^Package\sId\s+Version.+$") then
+            Some()
+        else
+            None
+
+    let (|Dashes|_|) line =
+        if String.forall ((=) '-') line then Some() else None
+
+    let (|Tools|_|) lines =
+        let tools =
+            lines
+            |> List.choose (fun (line: string) ->
+                let parts = line.Split([| ' ' |], StringSplitOptions.RemoveEmptyEntries)
+
+                if parts.Length > 2 then
+                    Some(parts.[0], parts.[1])
+                else
+                    None)
+
+        if List.isEmpty tools then None else Some tools
+
+    match lines with
+    | HeaderLine :: Dashes :: Tools tools ->
+        let tool =
+            List.tryFind
+                (fun (packageId, version) ->
+                    match (packageId, version) with
+                    | CompatibleToolName _, CompatibleVersion _ -> true
+                    | _ -> false)
+                tools
+
+        Option.map (snd >> FSharpLintVersion) tool
+    | _ -> None
+
+let private isWindows = RuntimeInformation.IsOSPlatform(OSPlatform.Windows)
+
+// Find an executable fsharplint file on the PATH
+let private fsharpLintVersionOnPath () : (FSharpLintExecutableFile * FSharpLintVersion) option =
+    let fsharpLintExecutableOnPathOpt =
+        Option.ofObj (Environment.GetEnvironmentVariable("FSHARPLINT_SEARCH_PATH_OVERRIDE"))
+        |> Option.orElse (Option.ofObj (Environment.GetEnvironmentVariable("PATH")))
+        |> function
+        | Some path -> path.Split([| if isWindows then ';' else ':' |], StringSplitOptions.RemoveEmptyEntries)
+        | None -> Array.empty
+        |> Seq.choose (fun folder ->
+            if isWindows then
+                let fsharpLintExe = Path.Combine(folder, $"{FSharpLintToolName}.exe")
+                if File.Exists fsharpLintExe then Some fsharpLintExe
+                else None
+            else
+                let fsharpLint = Path.Combine(folder, FSharpLintToolName)
+                if File.Exists fsharpLint then Some fsharpLint
+                else None)
+        |> Seq.tryHead
+        |> Option.bind File.From
+
+    fsharpLintExecutableOnPathOpt
+    |> Option.bind (fun fsharpLintExecutablePath ->
+        let processStart = ProcessStartInfo(
+            FileName = File.Unwrap fsharpLintExecutablePath,
+            Arguments = "--version",
+            CreateNoWindow = true,
+            RedirectStandardOutput = true,
+            RedirectStandardError = true,
+            UseShellExecute = false)
+
+        match startProcess processStart with
+        | Ok proc ->
+            proc.WaitForExit()
+            let stdOut = proc.StandardOutput.ReadToEnd()
+
+            stdOut
+            |> Option.ofObj
+            |> Option.bind (fun stdOut ->
+                if stdOut.Contains("Current version: ", StringComparison.CurrentCultureIgnoreCase) then
+                    let version = stdOut.ToLowerInvariant().Replace("current version: ", String.Empty).Trim()
+                    Some (FSharpLintExecutableFile(fsharpLintExecutablePath), FSharpLintVersion(version))
+                else
+                    None)
+        | Error(ProcessStartError.ExecutableFileNotFound _)
+        | Error(ProcessStartError.UnexpectedException _) -> None)
+
+let findFSharpLintTool (workingDir: Folder) : Result<FSharpLintToolFound, FSharpLintToolError> =
+    // First try and find a local tool for the folder.
+    // Next see if there is a global tool.
+    // Lastly check if an executable is present on the PATH.
+    let localToolsListResult = runToolListCmd workingDir false
+
+    match localToolsListResult with
+    | Ok(CompatibleTool version) -> Ok(FSharpLintToolFound(version, FSharpLintToolStartInfo.LocalTool workingDir))
+    | Error err -> Error(FSharpLintToolError.DotNetListError err)
+    | Ok _localToolListResult ->
+        let globalToolsListResult = runToolListCmd workingDir true
+
+        match globalToolsListResult with
+        | Ok(CompatibleTool version) -> Ok(FSharpLintToolFound(version, FSharpLintToolStartInfo.GlobalTool))
+        | Error err -> Error(FSharpLintToolError.DotNetListError err)
+        | Ok _nonCompatibleGlobalVersion ->
+            let onPathVersion = fsharpLintVersionOnPath ()
+
+            match onPathVersion with
+            | Some(executableFile, FSharpLintVersion(CompatibleVersion version)) ->
+                Ok(FSharpLintToolFound((FSharpLintVersion(version)), FSharpLintToolStartInfo.ToolOnPath executableFile))
+            | _ -> Error FSharpLintToolError.NoCompatibleVersionFound
+
+let createFor (startInfo: FSharpLintToolStartInfo) : Result<RunningFSharpLintTool, ProcessStartError> =
+    let processStart =
+        match startInfo with
+        | FSharpLintToolStartInfo.LocalTool(workingDirectory: Folder) ->
+            ProcessStartInfo(
+                FileName = "dotnet",
+                WorkingDirectory = Folder.Unwrap workingDirectory,
+                Arguments = $"{FSharpLintToolName} --daemon")
+        | FSharpLintToolStartInfo.GlobalTool ->
+            let userProfile = Environment.GetFolderPath(Environment.SpecialFolder.UserProfile)
+
+            let fsharpLintExecutable =
+                let fileName = if isWindows then $"{FSharpLintToolName}.exe" else FSharpLintToolName
+                Path.Combine(userProfile, ".dotnet", "tools", fileName)
+
+            ProcessStartInfo(
+                FileName = fsharpLintExecutable,
+                Arguments = "--daemon")
+        | FSharpLintToolStartInfo.ToolOnPath(FSharpLintExecutableFile executableFile) ->
+            ProcessStartInfo(
+                FileName = File.Unwrap executableFile,
+                Arguments = "--daemon")
+
+    processStart.UseShellExecute <- false
+    processStart.RedirectStandardInput <- true
+    processStart.RedirectStandardOutput <- true
+    processStart.RedirectStandardError <- true
+    processStart.CreateNoWindow <- true
+
+    match startProcess processStart with
+    | Ok daemonProcess ->
+        let handler = new HeaderDelimitedMessageHandler(
+            daemonProcess.StandardInput.BaseStream,
+            daemonProcess.StandardOutput.BaseStream)
+
+        let client = new JsonRpc(handler)
+
+        do client.StartListening()
+
+        try
+            // Get the version first as a sanity check that connection is possible
+            let _version =
+                client.InvokeAsync<string>(FSharpLint.Client.Contracts.Methods.Version)
+                |> Async.AwaitTask
+                |> Async.RunSynchronously
+
+            Ok
+                { RpcClient = client
+                  Process = daemonProcess
+                  StartInfo = startInfo }
+        with ex ->
+            let error =
+                if daemonProcess.HasExited then
+                    let stdErr = daemonProcess.StandardError.ReadToEnd()
+                    $"Daemon std error: {stdErr}.\nJsonRpc exception:{ex.Message}"
+                else
+                    ex.Message
+
+            Error(ProcessStartError.UnexpectedException(processStart.FileName, processStart.Arguments, error))
+    | Error err -> Error err

src/FSharpLint.Client/FSharpLintToolLocator.fsi

@@ -0,0 +1,7 @@
+module FSharpLint.Client.FSharpLintToolLocator
+
+open FSharpLint.Client.LSPFSharpLintServiceTypes
+
+val findFSharpLintTool: workingDir: Folder -> Result<FSharpLintToolFound, FSharpLintToolError>
+
+val createFor: startInfo: FSharpLintToolStartInfo -> Result<RunningFSharpLintTool, ProcessStartError>