[Emacs-diffs] scratch/backports-25.2 aad7ede 07/46: Ensure progress when fetching from the queue

[Noam Postavsky]

branch: scratch/backports-25.2
commit aad7ede227cd1a65780cf6a8cb500d6582315d22
Author: Lars Ingebrigtsen <address@hidden>
Commit: Noam Postavsky <address@hidden>

    Ensure progress when fetching from the queue
    
    * lisp/url/url-queue.el (url-queue-check-progress): Ensure
    that we have progress when fetching queued requests (bug#22576).
    
    (cherry picked from commit da66e5585083c2c357e960144fd4ae0e75310f74)
---
 lisp/url/url-queue.el |   18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/lisp/url/url-queue.el b/lisp/url/url-queue.el
index 0ff4ad1..8972d0b 100644
--- a/lisp/url/url-queue.el
+++ b/lisp/url/url-queue.el
@@ -1,4 +1,4 @@
-;;; url-queue.el --- Fetching web pages in parallel
+;;; url-queue.el --- Fetching web pages in parallel   -*- lexical-binding: t 
-*-
 
 ;; Copyright (C) 2011-2016 Free Software Foundation, Inc.
 
@@ -47,6 +47,7 @@
 ;;; Internal variables.
 
 (defvar url-queue nil)
+(defvar url-queue-progress-timer nil)
 
 (cl-defstruct url-queue
   url callback cbargs silentp
@@ -90,7 +91,13 @@ The variable `url-queue-timeout' sets a timeout."
     (when (and waiting
               (< running url-queue-parallel-processes))
       (setf (url-queue-pre-triggered waiting) t)
-      (run-with-idle-timer 0.01 nil 'url-queue-run-queue))))
+      ;; We start fetching from this idle timer...
+      (run-with-idle-timer 0.01 nil #'url-queue-run-queue)
+      ;; And then we set up a separate timer to ensure progress when a
+      ;; web server is unresponsive.
+      (unless url-queue-progress-timer
+        (setq url-queue-progress-timer
+              (run-with-idle-timer 1 1 #'url-queue-check-progress))))))
 
 (defun url-queue-run-queue ()
   (url-queue-prune-old-entries)
@@ -107,6 +114,13 @@ The variable `url-queue-timeout' sets a timeout."
       (setf (url-queue-start-time waiting) (float-time))
       (url-queue-start-retrieve waiting))))
 
+(defun url-queue-check-progress ()
+  (when url-queue-progress-timer
+    (if url-queue
+        (url-queue-run-queue)
+      (cancel-timer url-queue-progress-timer)
+      (setq url-queue-progress-timer nil))))
+
 (defun url-queue-callback-function (status job)
   (setq url-queue (delq job url-queue))
   (when (and (eq (car status) :error)