feat: basic lsp

Author: mhanberg

.dialyzer_ignore.exs

@@ -0,0 +1,3 @@
+[
+  {"lib/next_ls/lsp_supervisor.ex", :exact_eq}
+]

.formatter.exs

@@ -1,4 +1,20 @@
-# Used by "mix format"
 [
-  inputs: ["{mix,.formatter}.exs", "{config,lib,test}/**/*.{ex,exs}"]
+  locals_without_parens: [
+    assert_result: 2,
+    assert_notification: 2,
+    assert_result: 3,
+    assert_notification: 3,
+    notify: 2,
+    request: 2
+  ],
+  line_length: 120,
+  import_deps: [:gen_lsp],
+  inputs: [
+    "{mix,.formatter}.exs",
+    "{config,lib,}/**/*.{ex,exs}",
+    "test/next_ls_test.exs",
+    "test/test_helper.exs",
+    "test/next_ls/**/*.{ex,exs}",
+    "priv/**/*.ex"
+  ]
 ]

bin/nextls

@@ -0,0 +1,16 @@
+#!/usr/bin/env -S elixir --sname undefined
+
+System.no_halt(true)
+
+Logger.configure(level: :none)
+
+Mix.start()
+Mix.shell(Mix.Shell.Process)
+
+default_version = "0.1.0" # x-release-please-version
+
+Mix.install([{:next_ls, System.get_env("NEXTLS_VERSION", default_version)}])
+
+Logger.configure(level: :info)
+
+Application.ensure_all_started(:next_ls)

bin/start

@@ -0,0 +1,7 @@
+#!/usr/bin/env bash
+
+# used for local development
+
+cd "$(dirname "$0")"/.. || exit 1
+
+elixir --sname undefined -S mix run --no-halt -e "Application.ensure_all_started(:next_ls)" -- "$@"

lib/next_ls.ex

@@ -1,18 +1,235 @@
 defmodule NextLS do
-  @moduledoc """
-  Documentation for `NextLS`.
-  """
+  @moduledoc false
+  use GenLSP
 
-  @doc """
-  Hello world.
+  alias GenLSP.ErrorResponse
 
-  ## Examples
+  alias GenLSP.Enumerations.{
+    ErrorCodes,
+    TextDocumentSyncKind
+  }
 
-      iex> NextLS.hello()
-      :world
+  alias GenLSP.Notifications.{
+    Exit,
+    Initialized,
+    TextDocumentDidChange,
+    TextDocumentDidOpen,
+    TextDocumentDidSave
+  }
 
-  """
-  def hello do
-    :world
+  alias GenLSP.Requests.{Initialize, Shutdown}
+
+  alias GenLSP.Structures.{
+    DidOpenTextDocumentParams,
+    InitializeParams,
+    InitializeResult,
+    SaveOptions,
+    ServerCapabilities,
+    TextDocumentItem,
+    TextDocumentSyncOptions
+  }
+
+  def start_link(args) do
+    {args, opts} = Keyword.split(args, [:task_supervisor, :runtime_supervisor])
+
+    GenLSP.start_link(__MODULE__, args, opts)
+  end
+
+  @impl true
+  def init(lsp, args) do
+    task_supervisor = Keyword.fetch!(args, :task_supervisor)
+    runtime_supervisor = Keyword.fetch!(args, :runtime_supervisor)
+
+    {:ok,
+     assign(lsp,
+       exit_code: 1,
+       documents: %{},
+       refresh_refs: %{},
+       task_supervisor: task_supervisor,
+       runtime_supervisor: runtime_supervisor,
+       runtime_task: nil,
+       ready: false
+     )}
+  end
+
+  @impl true
+  def handle_request(
+        %Initialize{params: %InitializeParams{root_uri: root_uri}},
+        lsp
+      ) do
+    {:reply,
+     %InitializeResult{
+       capabilities: %ServerCapabilities{
+         text_document_sync: %TextDocumentSyncOptions{
+           open_close: true,
+           save: %SaveOptions{include_text: true},
+           change: TextDocumentSyncKind.full()
+         }
+       },
+       server_info: %{name: "NextLS"}
+     }, assign(lsp, root_uri: root_uri)}
+  end
+
+  def handle_request(%Shutdown{}, lsp) do
+    {:reply, nil, assign(lsp, exit_code: 0)}
+  end
+
+  def handle_request(%{method: method}, lsp) do
+    GenLSP.warning(lsp, "[NextLS] Method Not Found: #{method}")
+
+    {:reply,
+     %ErrorResponse{
+       code: ErrorCodes.method_not_found(),
+       message: "Method Not Found: #{method}"
+     }, lsp}
+  end
+
+  @impl true
+  def handle_notification(%Initialized{}, lsp) do
+    GenLSP.log(lsp, "[NextLS] LSP Initialized!")
+
+    working_dir = URI.parse(lsp.assigns.root_uri).path
+
+    GenLSP.log(lsp, "[NextLS] Booting runime...")
+
+    {:ok, runtime} =
+      DynamicSupervisor.start_child(
+        lsp.assigns.runtime_supervisor,
+        {NextLS.Runtime, working_dir: working_dir, parent: self()}
+      )
+
+    Process.monitor(runtime)
+
+    lsp = assign(lsp, runtime: runtime)
+
+    task =
+      Task.Supervisor.async_nolink(lsp.assigns.task_supervisor, fn ->
+        with false <-
+               wait_until(fn ->
+                 NextLS.Runtime.ready?(runtime)
+               end) do
+          GenLSP.error(lsp, "Failed to start runtime")
+          raise "Failed to boot runtime"
+        end
+
+        GenLSP.log(lsp, "[NextLS] Runtime ready...")
+
+        :ready
+      end)
+
+    {:noreply, assign(lsp, runtime_task: task)}
+  end
+
+  def handle_notification(%TextDocumentDidSave{}, %{assigns: %{ready: false}} = lsp) do
+    {:noreply, lsp}
+  end
+
+  def handle_notification(
+        %TextDocumentDidSave{
+          params: %GenLSP.Structures.DidSaveTextDocumentParams{
+            text: text,
+            text_document: %{uri: uri}
+          }
+        },
+        %{assigns: %{ready: true}} = lsp
+      ) do
+    {:noreply, lsp |> then(&put_in(&1.assigns.documents[uri], String.split(text, "\n")))}
+  end
+
+  def handle_notification(%TextDocumentDidChange{}, %{assigns: %{ready: false}} = lsp) do
+    {:noreply, lsp}
+  end
+
+  def handle_notification(%TextDocumentDidChange{}, lsp) do
+    for task <- Task.Supervisor.children(lsp.assigns.task_supervisor),
+        task != lsp.assigns.runtime_task do
+      Process.exit(task, :kill)
+    end
+
+    {:noreply, lsp}
+  end
+
+  def handle_notification(
+        %TextDocumentDidOpen{
+          params: %DidOpenTextDocumentParams{
+            text_document: %TextDocumentItem{text: text, uri: uri}
+          }
+        },
+        lsp
+      ) do
+    {:noreply, put_in(lsp.assigns.documents[uri], String.split(text, "\n"))}
+  end
+
+  def handle_notification(%Exit{}, lsp) do
+    System.halt(lsp.assigns.exit_code)
+
+    {:noreply, lsp}
+  end
+
+  def handle_notification(_notification, lsp) do
+    {:noreply, lsp}
+  end
+
+  def handle_info({ref, resp}, %{assigns: %{refresh_refs: refs}} = lsp)
+      when is_map_key(refs, ref) do
+    Process.demonitor(ref, [:flush])
+    {_token, refs} = Map.pop(refs, ref)
+
+    lsp =
+      case resp do
+        :ready ->
+          assign(lsp, ready: true)
+
+        _ ->
+          lsp
+      end
+
+    {:noreply, assign(lsp, refresh_refs: refs)}
+  end
+
+  def handle_info(
+        {:DOWN, ref, :process, _pid, _reason},
+        %{assigns: %{refresh_refs: refs}} = lsp
+      )
+      when is_map_key(refs, ref) do
+    {_token, refs} = Map.pop(refs, ref)
+
+    {:noreply, assign(lsp, refresh_refs: refs)}
+  end
+
+  def handle_info(
+        {:DOWN, _ref, :process, runtime, _reason},
+        %{assigns: %{runtime: runtime}} = lsp
+      ) do
+    GenLSP.error(lsp, "[NextLS] The runtime has crashed")
+
+    {:noreply, assign(lsp, runtime: nil)}
+  end
+
+  def handle_info({:log, message}, lsp) do
+    GenLSP.log(lsp, String.trim(message))
+
+    {:noreply, lsp}
+  end
+
+  def handle_info(_, lsp) do
+    {:noreply, lsp}
+  end
+
+  defp wait_until(cb) do
+    wait_until(120, cb)
+  end
+
+  defp wait_until(0, _cb) do
+    false
+  end
+
+  defp wait_until(n, cb) do
+    if cb.() do
+      true
+    else
+      Process.sleep(1000)
+      wait_until(n - 1, cb)
+    end
   end
 end

lib/next_ls/application.ex

@@ -7,10 +7,7 @@ defmodule NextLS.Application do
 
   @impl true
   def start(_type, _args) do
-    children = [
-      # Starts a worker by calling: NextLS.Worker.start_link(arg)
-      # {NextLS.Worker, arg}
-    ]
+    children = [NextLS.LSPSupervisor]
 
     # See https://hexdocs.pm/elixir/Supervisor.html
     # for other strategies and supported options

lib/next_ls/lsp_supervisor.ex

@@ -0,0 +1,45 @@
+defmodule NextLS.LSPSupervisor do
+  @moduledoc false
+
+  use Supervisor
+
+  @env Mix.env()
+
+  def start_link(init_arg) do
+    Supervisor.start_link(__MODULE__, init_arg, name: __MODULE__)
+  end
+
+  @impl true
+  def init(_init_arg) do
+    if @env == :test do
+      :ignore
+    else
+      {opts, _} =
+        OptionParser.parse!(System.argv(),
+          strict: [stdio: :boolean, port: :integer]
+        )
+
+      buffer_opts =
+        cond do
+          opts[:stdio] ->
+            []
+
+          is_integer(opts[:port]) ->
+            IO.puts("Starting on port #{opts[:port]}")
+            [communication: {GenLSP.Communication.TCP, [port: opts[:port]]}]
+
+          true ->
+            raise "Unknown option"
+        end
+
+      children = [
+        {DynamicSupervisor, name: NextLS.RuntimeSupervisor},
+        {Task.Supervisor, name: NextLS.TaskSupervisor},
+        {GenLSP.Buffer, buffer_opts},
+        {NextLS, task_supervisor: NextLS.TaskSupervisor, runtime_supervisor: NextLS.RuntimeSupervisor}
+      ]
+
+      Supervisor.init(children, strategy: :one_for_one)
+    end
+  end
+end