feat: add support for workspace folders

More information
https://bit.ly/3uou37n

lib/adapters/workspace-folders-adapter.ts

@@ -0,0 +1,41 @@
+import { LanguageClientConnection, WorkspaceFolder } from "../languageclient"
+import Convert from "../convert"
+import { basename } from "path"
+
+/** Public: Adapts the window/workspaceFolders command to Atom. */
+const WorkspaceFoldersAdapter = {
+  /** {@inheritDoc attach} */
+  attach,
+  /** {@inheritDoc getWorkspaceFolders} */
+  getWorkspaceFolders,
+}
+export default WorkspaceFoldersAdapter
+
+/**
+ * Public: Attach to a {LanguageClientConnection} to fetch the current open list of workspace folders.
+ *
+ * @param connection The {LanguageClientConnection}
+ * @param getProjectPaths A method that returns the open atom projects. This is passed from {ServerManager.getProjectPaths}
+ */
+export function attach(connection: LanguageClientConnection, getProjectPaths: () => string[]): void {
+  connection.onWorkspaceFolders(() => getWorkspaceFolders(getProjectPaths))
+}
+
+/**
+ * Public: fetch the current open list of workspace folders
+ *
+ * @param getProjectPaths A method that returns the open atom projects. This is passed from {ServerManager.getProjectPaths}
+ * @returns A {Promise} containing an {Array} of {lsp.WorkspaceFolder[]} or {null} if only a single file is open in the tool.
+ */
+export async function getWorkspaceFolders(getProjectPaths: () => string[]): Promise<WorkspaceFolder[] | null> {
+  const projectPaths = getProjectPaths()
+  if (projectPaths.length === 0) {
+    // only a single file is open
+    return null
+  } else {
+    return projectPaths.map((projectPath) => ({
+      uri: Convert.pathToUri(projectPath),
+      name: basename(projectPath),
+    }))
+  }
+}

lib/auto-languageclient.ts

@@ -22,13 +22,15 @@ import OutlineViewAdapter from "./adapters/outline-view-adapter"
 import RenameAdapter from "./adapters/rename-adapter"
 import SignatureHelpAdapter from "./adapters/signature-help-adapter"
 import * as ShowDocumentAdapter from "./adapters/show-document-adapter"
+import * as WorkspaceFoldersAdapter from "./adapters/workspace-folders-adapter"
 import * as Utils from "./utils"
 import { Socket } from "net"
 import { LanguageClientConnection } from "./languageclient"
 import { ConsoleLogger, FilteredLogger, Logger } from "./logger"
 import { LanguageServerProcess, ServerManager, ActiveServer } from "./server-manager.js"
 import { Disposable, CompositeDisposable, Point, Range, TextEditor } from "atom"
 import * as ac from "atom/autocomplete-plus"
+import { basename } from "path"
 
 export { ActiveServer, LanguageClientConnection, LanguageServerProcess }
 export type ConnectionType = "stdio" | "socket" | "ipc"
@@ -106,12 +108,13 @@ export default class AutoLanguageClient {
 
   /** (Optional) Return the parameters used to initialize a client - you may want to extend capabilities */
   protected getInitializeParams(projectPath: string, lsProcess: LanguageServerProcess): ls.InitializeParams {
+    const rootUri = Convert.pathToUri(projectPath)
     return {
       processId: lsProcess.pid,
       rootPath: projectPath,
-      rootUri: Convert.pathToUri(projectPath),
+      rootUri,
       locale: atom.config.get("atom-i18n.locale") || "en",
-      workspaceFolders: null,
+      workspaceFolders: [{ uri: rootUri, name: basename(projectPath) }],
       // The capabilities supported.
       // TODO the capabilities set to false/undefined are TODO. See {ls.ServerCapabilities} for a full list.
       capabilities: {
@@ -124,7 +127,7 @@ export default class AutoLanguageClient {
             changeAnnotationSupport: undefined,
             resourceOperations: ["create", "rename", "delete"],
           },
-          workspaceFolders: false,
+          workspaceFolders: true,
           didChangeConfiguration: {
             dynamicRegistration: false,
           },
@@ -570,6 +573,8 @@ export default class AutoLanguageClient {
     })
 
     ShowDocumentAdapter.attach(server.connection)
+
+    WorkspaceFoldersAdapter.attach(server.connection, this._serverManager.getProjectPaths)
   }
 
   public shouldSyncForEditor(editor: TextEditor, projectPath: string): boolean {

lib/languageclient.ts

@@ -281,6 +281,17 @@ export class LanguageClientConnection extends EventEmitter {
     this._sendNotification(lsp.DidChangeWatchedFilesNotification.type, params)
   }
 
+  /**
+   * Public: Register a callback for the `workspace.workspaceFolders` request. This request is sent from the server to
+   * Atom to fetch the current open list of workspace folders
+   *
+   * @param A Callback which returns a {Promise} containing an {Array} of {lsp.WorkspaceFolder[]} or {null} if only a
+   *   single file is open in the tool.
+   */
+  public onWorkspaceFolders(callback: () => Promise<lsp.WorkspaceFolder[] | null>): void {
+    return this._onRequest(lsp.WorkspaceFoldersRequest.type, callback)
+  }
+
   /**
    * Public: Register a callback for the `textDocument/publishDiagnostics` message.
    *

lib/server-manager.ts

@@ -255,6 +255,10 @@ export class ServerManager {
     this._normalizedProjectPaths = atom.project.getDirectories().map((d) => this.normalizePath(d.getPath()))
   }
 
+  public getProjectPaths(): string[] {
+    return this._normalizedProjectPaths
+  }
+
   public normalizePath(projectPath: string): string {
     return !projectPath.endsWith(path.sep) ? path.join(projectPath, path.sep) : projectPath
   }