1 files changed, 113 insertions, 0 deletions
diff --git a/src/Server.zig b/src/Server.zig
new file mode 100644
index 0000000000..a25dc93857
--- /dev/null
+++ b/src/Server.zig
@@ -0,0 +1,113 @@
+in: std.fs.File,
+out: std.fs.File,
+receive_fifo: std.fifo.LinearFifo(u8, .Dynamic),
+
+pub const Options = struct {
+    gpa: Allocator,
+    in: std.fs.File,
+    out: std.fs.File,
+};
+
+pub fn init(options: Options) !Server {
+    var s: Server = .{
+        .in = options.in,
+        .out = options.out,
+        .receive_fifo = std.fifo.LinearFifo(u8, .Dynamic).init(options.gpa),
+    };
+    try s.serveStringMessage(.zig_version, build_options.version);
+    return s;
+}
+
+pub fn deinit(s: *Server) void {
+    s.receive_fifo.deinit();
+    s.* = undefined;
+}
+
+pub fn receiveMessage(s: *Server) !InMessage.Header {
+    const Header = InMessage.Header;
+    const fifo = &s.receive_fifo;
+
+    while (true) {
+        const buf = fifo.readableSlice(0);
+        assert(fifo.readableLength() == buf.len);
+        if (buf.len >= @sizeOf(Header)) {
+            const header = @ptrCast(*align(1) const Header, buf[0..@sizeOf(Header)]);
+            if (header.bytes_len != 0)
+                return error.InvalidClientMessage;
+            const result = header.*;
+            fifo.discard(@sizeOf(Header));
+            return result;
+        }
+
+        const write_buffer = try fifo.writableWithSize(256);
+        const amt = try s.in.read(write_buffer);
+        fifo.update(amt);
+    }
+}
+
+pub fn serveStringMessage(s: *Server, tag: OutMessage.Tag, msg: []const u8) !void {
+    return s.serveMessage(.{
+        .tag = tag,
+        .bytes_len = @intCast(u32, msg.len),
+    }, &.{msg});
+}
+
+pub fn serveMessage(
+    s: *const Server,
+    header: OutMessage.Header,
+    bufs: []const []const u8,
+) !void {
+    var iovecs: [10]std.os.iovec_const = undefined;
+    iovecs[0] = .{
+        .iov_base = @ptrCast([*]const u8, &header),
+        .iov_len = @sizeOf(OutMessage.Header),
+    };
+    for (bufs, iovecs[1 .. bufs.len + 1]) |buf, *iovec| {
+        iovec.* = .{
+            .iov_base = buf.ptr,
+            .iov_len = buf.len,
+        };
+    }
+    try s.out.writevAll(iovecs[0 .. bufs.len + 1]);
+}
+
+pub fn serveEmitBinPath(
+    s: *Server,
+    fs_path: []const u8,
+    header: std.zig.Server.Message.EmitBinPath,
+) !void {
+    try s.serveMessage(.{
+        .tag = .emit_bin_path,
+        .bytes_len = @intCast(u32, fs_path.len + @sizeOf(std.zig.Server.Message.EmitBinPath)),
+    }, &.{
+        std.mem.asBytes(&header),
+        fs_path,
+    });
+}
+
+pub fn serveErrorBundle(s: *Server, error_bundle: std.zig.ErrorBundle) !void {
+    const eb_hdr: std.zig.Server.Message.ErrorBundle = .{
+        .extra_len = @intCast(u32, error_bundle.extra.len),
+        .string_bytes_len = @intCast(u32, error_bundle.string_bytes.len),
+    };
+    const bytes_len = @sizeOf(std.zig.Server.Message.ErrorBundle) +
+        4 * error_bundle.extra.len + error_bundle.string_bytes.len;
+    try s.serveMessage(.{
+        .tag = .error_bundle,
+        .bytes_len = @intCast(u32, bytes_len),
+    }, &.{
+        std.mem.asBytes(&eb_hdr),
+        // TODO: implement @ptrCast between slices changing the length
+        std.mem.sliceAsBytes(error_bundle.extra),
+        error_bundle.string_bytes,
+    });
+}
+
+const OutMessage = std.zig.Server.Message;
+const InMessage = std.zig.Client.Message;
+
+const Server = @This();
+const std = @import("std");
+const build_options = @import("build_options");
+const Allocator = std.mem.Allocator;
+const assert = std.debug.assert;