From c4d5ddb9ce5cdb8c283928daf6b166e4ce5a430d Mon Sep 17 00:00:00 2001
From: Daniel Pettersson <daniel@dpettersson.net>
Date: Wed, 28 Feb 2024 13:03:56 +0100
Subject: [PATCH] Jsonrpc: improve performance of process filter function

`run-at-time' keeps `timer-list' list sorted by inserting each timer
based on the timer value.  This means that `timer--time-less-p' needs is
executed ~ N*N/2 times for each N pending messages.  This means that
jsonrpc becomes unusable for connections that generate a lot messages at
the same time.

* lisp/jsonrpc.el (Version): Bump to 1.0.25
(jsonrpc--process-filter): Improve performance
---
 lisp/jsonrpc.el | 28 +++++++++++++++++++---------
 1 file changed, 19 insertions(+), 9 deletions(-)

diff --git a/lisp/jsonrpc.el b/lisp/jsonrpc.el
index 14fe0447008..5037d8c5b2b 100644
--- a/lisp/jsonrpc.el
+++ b/lisp/jsonrpc.el
@@ -4,7 +4,7 @@
 
 ;; Author: João Távora <joaotavora@gmail.com>
 ;; Keywords: processes, languages, extensions
-;; Version: 1.0.24
+;; Version: 1.0.25
 ;; Package-Requires: ((emacs "25.2"))
 
 ;; This is a GNU ELPA :core package.  Avoid functionality that is not
@@ -760,10 +760,11 @@ jsonrpc--process-filter
                                 (setq message
                                       (plist-put message :jsonrpc-json
                                                  (buffer-string)))
-                                (process-put proc 'jsonrpc-mqueue
-                                             (nconc (process-get proc
-                                                                 'jsonrpc-mqueue)
-                                                    (list message)))))
+                                ;; Put new messages at the front of the queue,
+                                ;; this is correct as the order is reversed
+                                ;; before putting the timers on `timer-list'.
+                                (push message
+                                      (process-get proc 'jsonrpc-mqueue))))
                           (goto-char message-end)
                           (let ((inhibit-read-only t))
                             (delete-region (point-min) (point)))
@@ -782,11 +783,20 @@ jsonrpc--process-filter
           ;; non-locally (typically the reply to a request), so do
           ;; this all this processing in top-level loops timer.
           (cl-loop
+           ;; `timer-activate' orders timers by time, which is an
+           ;; very expensive operation when jsonrpc-mqueue is large,
+           ;; therefore the time object is reused for each timer
+           ;; created.
+           with time = (current-time)
            for msg = (pop (process-get proc 'jsonrpc-mqueue)) while msg
-           do (run-at-time 0 nil
-                           (lambda (m) (with-temp-buffer
-                                         (jsonrpc-connection-receive conn m)))
-                           msg)))))))
+           do (let ((timer (timer-create)))
+                (timer-set-time timer time)
+                (timer-set-function timer
+                                    (lambda (conn msg)
+                                      (with-temp-buffer
+                                        (jsonrpc-connection-receive conn msg)))
+                                    (list conn msg))
+                (timer-activate timer))))))))
 
 (defun jsonrpc--remove (conn id &optional deferred-spec)
   "Cancel CONN's continuations for ID, including its timer, if it exists.
-- 
2.39.3 (Apple Git-145)