77 lines
1.8 KiB
PHP
77 lines
1.8 KiB
PHP
<?php
|
|
|
|
// Provide some ability to lock a PHP function so that multiple processes
|
|
// can't run the function concurrently
|
|
if(! function_exists('lock_function')) {
|
|
function lock_function($fn_name, $block = true, $wait_sec = 2) {
|
|
if( $wait_sec == 0 )
|
|
$wait_sec = 2; // don't let the user pick a value that's likely to crash the system
|
|
|
|
$got_lock = false;
|
|
|
|
do {
|
|
q("LOCK TABLE locks WRITE");
|
|
$r = q("SELECT locked FROM locks WHERE name = '%s' LIMIT 1",
|
|
dbesc($fn_name)
|
|
);
|
|
|
|
if((count($r)) && (! $r[0]['locked'])) {
|
|
q("UPDATE locks SET locked = 1 WHERE name = '%s' LIMIT 1",
|
|
dbesc($fn_name)
|
|
);
|
|
$got_lock = true;
|
|
}
|
|
elseif(! $r) { // the Boolean value for count($r) should be equivalent to the Boolean value of $r
|
|
q("INSERT INTO locks ( name, locked ) VALUES ( '%s', 1 )",
|
|
dbesc($fn_name)
|
|
);
|
|
$got_lock = true;
|
|
}
|
|
|
|
q("UNLOCK TABLES");
|
|
|
|
if(($block) && (! $got_lock))
|
|
sleep($wait_sec);
|
|
|
|
} while(($block) && (! $got_lock));
|
|
|
|
logger('lock_function: function ' . $fn_name . ' with blocking = ' . $block . ' got_lock = ' . $got_lock, LOGGER_DEBUG);
|
|
|
|
return $got_lock;
|
|
}}
|
|
|
|
|
|
if(! function_exists('block_on_function_lock')) {
|
|
function block_on_function_lock($fn_name, $wait_sec = 2) {
|
|
if( $wait_sec == 0 )
|
|
$wait_sec = 2; // don't let the user pick a value that's likely to crash the system
|
|
|
|
do {
|
|
$r = q("SELECT locked FROM locks WHERE name = '%s' LIMIT 1",
|
|
dbesc($fn_name)
|
|
);
|
|
|
|
if(count($r) && $r[0]['locked'])
|
|
sleep($wait_sec);
|
|
|
|
} while(count($r) && $r[0]['locked']);
|
|
|
|
return;
|
|
}}
|
|
|
|
|
|
if(! function_exists('unlock_function')) {
|
|
function unlock_function($fn_name) {
|
|
//$r = q("LOCK TABLE lock WRITE");
|
|
$r = q("UPDATE locks SET locked = 0 WHERE name = '%s' LIMIT 1",
|
|
dbesc($fn_name)
|
|
);
|
|
//$r = q("UNLOCK TABLES");
|
|
|
|
logger('unlock_function: released lock for function ' . $fn_name, LOGGER_DEBUG);
|
|
|
|
return;
|
|
}}
|
|
|
|
?>
|