ce7cb702218693d08ea6d83464d2457c9250027c

packages/fsharp-runner/hostexec/GnuProxy.cs

@@ -0,0 +1,114 @@
+using System.Diagnostics.CodeAnalysis;
+using System.Text.Json;
+
+namespace Quorate.HostExec;
+
+[SuppressMessage("Maintainability", "CA1515", Justification = "Loaded by F# actions.")]
+public enum GnuTool
+{
+    C,
+    Cpp,
+    Gcc,
+    Gxx
+}
+
+[SuppressMessage("Maintainability", "CA1515", Justification = "Loaded by F# actions.")]
+public sealed class ToolRoot
+{
+    private ToolRoot(string path)
+    {
+        Path = path;
+    }
+
+    public string Path { get; }
+
+    public static ToolRoot Open(string path)
+    {
+        ArgumentException.ThrowIfNullOrWhiteSpace(path);
+
+        if (!System.IO.Path.IsPathFullyQualified(path))
+        {
+            throw new ArgumentException("tool root must be absolute", nameof(path));
+        }
+
+        var fullPath = System.IO.Path.GetFullPath(path);
+
+        if (!Directory.Exists(fullPath))
+        {
+            throw new DirectoryNotFoundException(fullPath);
+        }
+
+        return new ToolRoot(fullPath);
+    }
+
+    internal string Resolve(string relative)
+    {
+        if (System.IO.Path.IsPathFullyQualified(relative))
+        {
+            throw new ArgumentException("tool path must be relative", nameof(relative));
+        }
+
+        var path = System.IO.Path.GetFullPath(System.IO.Path.Combine(Path, relative));
+        var prefix = Path + System.IO.Path.DirectorySeparatorChar;
+
+        if (!path.StartsWith(prefix, StringComparison.Ordinal))
+        {
+            throw new ArgumentException("tool path escapes its root", nameof(relative));
+        }
+
+        return path;
+    }
+}
+
+[SuppressMessage("Maintainability", "CA1515", Justification = "Loaded by F# actions.")]
+public static class GnuProxy
+{
+    private const string Launcher = "#!/usr/share/dotnet/dotnet /opt/fsi/packages/HostExec.dll\n";
+
+    private static readonly JsonSerializerOptions Json = new()
+    {
+        PropertyNamingPolicy = JsonNamingPolicy.CamelCase
+    };
+
+    public static string Install(ToolRoot root, GnuTool tool)
+    {
+        ArgumentNullException.ThrowIfNull(root);
+        var name = Name(tool);
+        var relative = $"usr/bin/{name}";
+        var executable = root.Resolve(relative);
+
+        if (!File.Exists(executable))
+        {
+            throw new FileNotFoundException("GNU tool is unavailable", executable);
+        }
+
+        var target = root.Resolve($"usr/local/bin/{name}");
+        Directory.CreateDirectory(System.IO.Path.GetDirectoryName(target)!);
+        File.WriteAllText(target, Launcher);
+        File.SetUnixFileMode(
+            target,
+            UnixFileMode.UserRead
+            | UnixFileMode.UserWrite
+            | UnixFileMode.UserExecute
+            | UnixFileMode.GroupRead
+            | UnixFileMode.GroupExecute
+            | UnixFileMode.OtherRead
+            | UnixFileMode.OtherExecute
+        );
+
+        File.WriteAllText($"{target}.json", JsonSerializer.Serialize(new ProxyFile(1, "gnu", relative), Json));
+        return target;
+    }
+
+    private static string Name(GnuTool tool) =>
+        tool switch
+        {
+            GnuTool.C => "cc",
+            GnuTool.Cpp => "c++",
+            GnuTool.Gcc => "gcc",
+            GnuTool.Gxx => "g++",
+            _ => throw new ArgumentOutOfRangeException(nameof(tool))
+        };
+}
+
+internal sealed record ProxyFile(int Version, string Kind, string File);