]> git.mxchange.org Git - friendica.git/blob - include/lock.php
Merge pull request #2471 from annando/1604-diaspora-always-on
[friendica.git] / include / lock.php
1 <?php
2
3 // Provide some ability to lock a PHP function so that multiple processes
4 // can't run the function concurrently
5 if(! function_exists('lock_function')) {
6 function lock_function($fn_name, $block = true, $wait_sec = 2, $timeout = 30) {
7         if( $wait_sec == 0 )
8                 $wait_sec = 2;  // don't let the user pick a value that's likely to crash the system
9
10         $got_lock = false;
11         $start = time();
12
13         do {
14                 q("LOCK TABLE `locks` WRITE");
15                 $r = q("SELECT `locked`, `created` FROM `locks` WHERE `name` = '%s' LIMIT 1",
16                         dbesc($fn_name)
17                 );
18
19                 if((count($r)) AND (!$r[0]['locked'] OR (strtotime($r[0]['created']) < time() - 3600))) {
20                         q("UPDATE `locks` SET `locked` = 1, `created` = '%s' WHERE `name` = '%s'",
21                                 dbesc(datetime_convert()),
22                                 dbesc($fn_name)
23                         );
24                         $got_lock = true;
25                 }
26                 elseif(! $r) { // the Boolean value for count($r) should be equivalent to the Boolean value of $r
27                         q("INSERT INTO `locks` (`name`, `created`, `locked`) VALUES ('%s', '%s', 1)",
28                                 dbesc($fn_name),
29                                 dbesc(datetime_convert())
30                         );
31                         $got_lock = true;
32                 }
33
34                 q("UNLOCK TABLES");
35
36                 if(($block) && (! $got_lock))
37                         sleep($wait_sec);
38
39         } while(($block) && (! $got_lock) && ((time() - $start) < $timeout));
40
41         logger('lock_function: function ' . $fn_name . ' with blocking = ' . $block . ' got_lock = ' . $got_lock . ' time = ' . (time() - $start), LOGGER_DEBUG);
42
43         return $got_lock;
44 }}
45
46
47 if(! function_exists('block_on_function_lock')) {
48 function block_on_function_lock($fn_name, $wait_sec = 2, $timeout = 30) {
49         if( $wait_sec == 0 )
50                 $wait_sec = 2;  // don't let the user pick a value that's likely to crash the system
51
52         $start = time();
53
54         do {
55                 $r = q("SELECT locked FROM locks WHERE name = '%s' LIMIT 1",
56                                 dbesc($fn_name)
57                      );
58
59                 if(count($r) && $r[0]['locked'])
60                         sleep($wait_sec);
61
62         } while(count($r) && $r[0]['locked'] && ((time() - $start) < $timeout));
63
64         return;
65 }}
66
67
68 if(! function_exists('unlock_function')) {
69 function unlock_function($fn_name) {
70         $r = q("UPDATE `locks` SET `locked` = 0, `created` = '0000-00-00 00:00:00' WHERE `name` = '%s'",
71                         dbesc($fn_name)
72              );
73
74         logger('unlock_function: released lock for function ' . $fn_name, LOGGER_DEBUG);
75
76         return;
77 }}