From 2a31e628f1d3fe3f0d5f89061f03c08dba16c6f9 Mon Sep 17 00:00:00 2001
From: Andrew Nicols <andrew@nicols.co.uk>
Date: Tue, 24 Oct 2017 08:08:13 +0800
Subject: [PATCH] MDL-57477 session: Comment tidyup

---
 lib/classes/session/memcached.php | 46 ++++++++++++++-----------------
 1 file changed, 21 insertions(+), 25 deletions(-)

diff --git a/lib/classes/session/memcached.php b/lib/classes/session/memcached.php
index c7853379007..5854f457d4d 100644
--- a/lib/classes/session/memcached.php
+++ b/lib/classes/session/memcached.php
@@ -36,19 +36,23 @@ defined('MOODLE_INTERNAL') || die();
 class memcached extends handler {
     /** @var string $savepath save_path string  */
     protected $savepath;
+
     /** @var array $servers list of servers parsed from save_path */
     protected $servers;
+
     /** @var string $prefix session key prefix  */
     protected $prefix;
+
     /** @var int $acquiretimeout how long to wait for session lock */
     protected $acquiretimeout = 120;
+
     /**
      * @var int $lockexpire how long to wait before expiring the lock so that other requests
      * may continue execution, ignored if PECL memcached is below version 2.2.0.
      */
     protected $lockexpire = 7200;
+
     /**
-     *
      * @var integer $lockretrysleep Used for memcached 3.x (PHP7), the amount of time to
      * sleep between attempts to acquire the session lock. Mimics the deprecated config
      * memcached.sess_lock_wait.
@@ -109,7 +113,6 @@ class memcached extends handler {
 
         $result = parent::start();
 
-        // MDL-53713...
         // If session_start returned TRUE, but it took as long
         // as the timeout value, and the $_SESSION returned is
         // empty when should not have been (isnewsession false)
@@ -148,34 +151,27 @@ class memcached extends handler {
         ini_set('memcached.sess_locking', '1'); // Locking is required!
         ini_set('memcached.sess_lock_expire', $this->lockexpire);
 
-        // MDL-57477, MDL-53713...
         if (version_compare($version, '3.0.0-dev') >= 0) {
-            // With memcached 3.x (PHP 7) we configure the max retries to make
-            // and the time to sleep between each retry. There are two sleep
-            // config values, an initial and a max value. After each attempt
-            // the memcached module adjusts the sleep value to be the lesser of
-            // the configured max value, or 2X the previous value. With default
-            // memcached.ini configs (5, 1s, 2s) the result is only 5 attempts
-            // to lock over 9 sec. To mimic the behavior of the 2.2.x module so
-            // we get more attempts and much more frequently, config both sleep
-            // values to the old default value of 150 msec (making it constant)
-            // and calculate number of retries using the existing Moodle config
-            // $CFG->session_memcached_acquire_lock_timeout. Doing this so
-            // admins configure session lock attempt timeout in familiar terms,
-            // and more straight-forward to detect if lock attempt timeout has
-            // occurred in start(). If _min and _max values are not equal, the
-            // actual lock acquire timeout will not be the expected configured
-            // value in $CFG->session_memcached_acquire_lock_timeout; this will
-            // cause session data loss when failure to acquire the lock is not
-            // detected.
+            // With memcached 3.x (PHP 7) we configure the max retries to make and the time to sleep between each retry.
+            // There are two sleep config values, an initial and a max value.
+            // After each attempt the memcached module adjusts the sleep value to be the lesser of the configured max
+            // value, or 2X the previous value.
+            // With default memcached.ini configs (5, 1s, 2s) the result is only 5 attempts to lock over 9 sec.
+            // To mimic the behavior of the 2.2.x module so we get more attempts and much more frequently, config both
+            // sleep values to the old default value of 150 msec (making it constant) and calculate number of retries
+            // using the existing Moodle config $CFG->session_memcached_acquire_lock_timeout.
+            // Doing this so admins configure session lock attempt timeout in familiar terms, and more straight-forward
+            // to detect if lock attempt timeout has occurred in start().
+            // If _min and _max values are not equal, the actual lock acquire timeout will not be the expected
+            // configured value in $CFG->session_memcached_acquire_lock_timeout; this will cause session data loss when
+            // failure to acquire the lock is not detected.
             ini_set('memcached.sess_lock_wait_min', $this->lockretrysleep);
             ini_set('memcached.sess_lock_wait_max', $this->lockretrysleep);
             ini_set('memcached.sess_lock_retries', (int)(($this->acquiretimeout * 1000) / $this->lockretrysleep) + 1);
         } else {
-            // With memcached 2.2.x we configure max time to attempt lock, and
-            // accept default value (in memcached.ini) for sleep time between
-            // each attempt (usually 150 msec), then memcached calculates the
-            // max number of retries to make.
+            // With memcached 2.2.x we configure max time to attempt lock, and accept default value (in memcached.ini)
+            // for sleep time between each attempt (usually 150 msec), then memcached calculates the max number of
+            // retries to make.
             ini_set('memcached.sess_lock_max_wait', $this->acquiretimeout);
         }