From a4d7c5028d49cd5fd6d5599e91d2bcfb250851dc Mon Sep 17 00:00:00 2001
From: dannyfreeman <danny@dfreeman.email>
Date: Wed, 9 Nov 2022 08:46:45 -0500
Subject: [PATCH 2/2] Eglot: Display progress notifications in minibuffer as
 they arrive

* lisp/progmodes/eglot.el (eglot-report-progress): New custom variable.
(eglot-lsp-server): New slot for tracking active progress reporters.
(eglot-handle-notification): New impl for $/progress server responses.

The LSP spec describes methods for reporting progress on long running
jobs to the client:

https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#progress
https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#workDoneProgress

This change reports those notifications in the minibuffer as they come
in. It shows a percent indicator (if the server provides theme), or a
spinner. This change should open the door for writing a "cancel long
running request" command, which are identified by these progress
notifications. See
https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#window_workDoneProgress_cancel
---
 lisp/progmodes/eglot.el | 50 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

diff --git a/lisp/progmodes/eglot.el b/lisp/progmodes/eglot.el
index e6e97fd8c8..e6673c37a1 100644
--- a/lisp/progmodes/eglot.el
+++ b/lisp/progmodes/eglot.el
@@ -386,6 +386,11 @@ eglot-menu-string
   "String displayed in mode line when Eglot is active."
   :type 'string)
 
+(defcustom eglot-report-progress t
+  "If non-nil, show progress of long running server work in the minibuffer."
+  :type 'boolean
+  :version "29.1")
+
 (defvar eglot-withhold-process-id nil
   "If non-nil, Eglot will not send the Emacs process id to the language server.
 This can be useful when using docker to run a language server.")
@@ -470,6 +475,7 @@ eglot--executable-find
       (TextDocumentEdit (:textDocument :edits) ())
       (TextEdit (:range :newText))
       (VersionedTextDocumentIdentifier (:uri :version) ())
+      (WorkDoneProgress (:kind) (:title :message :percentage :cancellable))
       (WorkspaceEdit () (:changes :documentChanges))
       (WorkspaceSymbol (:name :kind) (:containerName :location :data)))
     "Alist (INTERFACE-NAME . INTERFACE) of known external LSP interfaces.
@@ -831,6 +837,9 @@ eglot-lsp-server
    (project
     :documentation "Project associated with server."
     :accessor eglot--project)
+   (progress-reporter-alist
+    :documentation "Alist of (PROGRESS-TOKEN . PROGRESS-REPORTER)."
+    :accessor eglot--progress-reporter-alist)
    (inhibit-autoreconnect
     :initform t
     :documentation "Generalized boolean inhibiting auto-reconnection if true."
@@ -2049,6 +2058,47 @@ eglot-handle-notification
   (_server (_method (eql telemetry/event)) &rest _any)
   "Handle notification telemetry/event.") ;; noop, use events buffer
 
+(cl-defmethod eglot-handle-notification
+  (server (_method (eql $/progress)) &key token value)
+  "Handle a $/progress notification identified by TOKEN from the SERVER."
+  (when eglot-report-progress
+    (cl-flet ((eglot--pr-message (title message)
+                (cond
+                 ((and title message) (format "%s %s" title message))
+                 (title title)
+                 (message message)))
+              (eglot--get-pr (server token)
+                 (cdr (assoc token (eglot--progress-reporter-alist server))))
+              (eglot--delete-pr (server token)
+                (setf (eglot--progress-reporter-alist server)
+                      (assoc-delete-all
+                       token (eglot--progress-reporter-alist server)))))
+      (eglot--dbind ((WorkDoneProgress) kind title percentage message) value
+        (pcase kind
+          ("begin"
+           (let* ((prefix (format (concat "[eglot] %s %s:"
+                                          (when percentage " "))
+                                  (eglot-project-nickname server)
+                                  token))
+                  (pr (if percentage
+                          (make-progress-reporter
+                           prefix 0 100 percentage 1 0)
+                        (make-progress-reporter
+                         prefix nil nil nil 1 0))))
+             (eglot--delete-pr server token)
+             (setf (eglot--progress-reporter-alist server)
+                   (cons (cons token pr) (eglot--progress-reporter-alist server)))
+             (progress-reporter-update
+              pr percentage (eglot--pr-message title message))))
+          ("report"
+           (when-let ((pr (eglot--get-pr server token)))
+             (progress-reporter-update
+              pr percentage (eglot--pr-message title message))))
+          ("end"
+           (when-let ((pr (eglot--get-pr server token)))
+             (progress-reporter-done pr)
+             (eglot--delete-pr server token))))))))
+
 (cl-defmethod eglot-handle-notification
   (_server (_method (eql textDocument/publishDiagnostics)) &key uri diagnostics
            &allow-other-keys) ; FIXME: doesn't respect `eglot-strict-mode'
-- 
2.38.1