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) {
8 $wait_sec = 2; // don't let the user pick a value that's likely to crash the system
13 q("LOCK TABLE lock WRITE");
14 $r = q("SELECT locked FROM lock WHERE name = '%s' LIMIT 1",
18 if((count($r)) && (! $r[0]['locked'])) {
19 q("UPDATE lock SET locked = 1 WHERE name = '%s' LIMIT 1",
24 elseif(! $r) { // the Boolean value for count($r) should be equivalent to the Boolean value of $r
25 q("INSERT INTO lock ( name, locked ) VALUES ( '%s', 1 )",
33 if(($block) && (! $got_lock))
36 } while(($block) && (! $got_lock));
38 logger('lock_function: function ' . $fn_name . ' with blocking = ' . $block . ' got_lock = ' . $got_lock, LOGGER_DEBUG);
44 if(! function_exists('block_on_function_lock')) {
45 function block_on_function_lock($fn_name, $wait_sec = 2) {
47 $wait_sec = 2; // don't let the user pick a value that's likely to crash the system
50 $r = q("SELECT locked FROM lock WHERE name = '%s' LIMIT 1",
54 if(count($r) && $r[0]['locked'])
57 } while(count($r) && $r[0]['locked']);
63 if(! function_exists('unlock_function')) {
64 function unlock_function(fn_name) {
65 //$r = q("LOCK TABLE lock WRITE");
66 $r = q("UPDATE lock SET locked = 0 WHERE name = '%s' LIMIT 1",
69 //$r = q("UNLOCK TABLES");
71 logger('unlock_function: released lock for function ' . fn_name, LOGGER_DEBUG);