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Arsse/lib/Db/AbstractDriver.php
J. King b3f631e335 Use more reliable database locking strategy; reorganize tests
PostgreSQL and MySQL both have better locking mechanisms than what was previously implemented, as well
2017-07-07 21:06:38 -04:00

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5.1 KiB
PHP

<?php
declare(strict_types=1);
namespace JKingWeb\Arsse\Db;
use JKingWeb\DrUUID\UUID as UUID;
abstract class AbstractDriver implements Driver {
protected $locked = false;
protected $transDepth = 0;
protected $transStatus = [];
public abstract function prepareArray(string $query, array $paramTypes): Statement;
protected abstract function lock(): bool;
protected abstract function unlock(bool $rollback = false) : bool;
public function schemaVersion(): int {
try {
return (int) $this->query("SELECT value from arsse_meta where key is schema_version")->getValue();
} catch(Exception $e) {
return 0;
}
}
public function begin(bool $lock = false): Transaction {
return new Transaction($this, $lock);
}
public function savepointCreate(bool $lock = false): int {
if($lock && !$this->transDepth) {
$this->lock();
$this->locked = true;
}
$this->exec("SAVEPOINT arsse_".(++$this->transDepth));
$this->transStatus[$this->transDepth] = self::TR_PEND;
return $this->transDepth;
}
public function savepointRelease(int $index = null): bool {
if(is_null($index)) $index = $this->transDepth;
if(array_key_exists($index, $this->transStatus)) {
switch($this->transStatus[$index]) {
case self::TR_PEND:
$this->exec("RELEASE SAVEPOINT arsse_".$index);
$this->transStatus[$index] = self::TR_COMMIT;
$a = $index;
while(++$a && $a <= $this->transDepth) {
if($this->transStatus[$a] <= self::TR_PEND) $this->transStatus[$a] = self::TR_PEND_COMMIT;
}
$out = true;
break;
case self::TR_PEND_COMMIT:
$this->transStatus[$index] = self::TR_COMMIT;
$out = true;
break;
case self::TR_PEND_ROLLBACK:
$this->transStatus[$index] = self::TR_COMMIT;
$out = false;
break;
case self::TR_COMMIT:
case self::TR_ROLLBACK:
throw new ExceptionSavepoint("stale", ['action' => "commit", 'index' => $index]);
default:
throw new Exception("unknownSavepointStatus", $this->transStatus[$index]);
}
if($index==$this->transDepth) {
while($this->transDepth > 0 && $this->transStatus[$this->transDepth] > self::TR_PEND) {
array_pop($this->transStatus);
$this->transDepth--;
}
}
if(!$this->transDepth && $this->locked) {
$this->unlock();
$this->locked = false;
}
return $out;
} else {
throw new ExceptionSavepoint("invalid", ['action' => "commit", 'index' => $index]);
}
}
public function savepointUndo(int $index = null): bool {
if(is_null($index)) $index = $this->transDepth;
if(array_key_exists($index, $this->transStatus)) {
switch($this->transStatus[$index]) {
case self::TR_PEND:
$this->exec("ROLLBACK TRANSACTION TO SAVEPOINT arsse_".$index);
$this->exec("RELEASE SAVEPOINT arsse_".$index);
$this->transStatus[$index] = self::TR_ROLLBACK;
$a = $index;
while(++$a && $a <= $this->transDepth) {
if($this->transStatus[$a] <= self::TR_PEND) $this->transStatus[$a] = self::TR_PEND_ROLLBACK;
}
$out = true;
break;
case self::TR_PEND_COMMIT:
$this->transStatus[$index] = self::TR_ROLLBACK;
$out = false;
break;
case self::TR_PEND_ROLLBACK:
$this->transStatus[$index] = self::TR_ROLLBACK;
$out = true;
break;
case self::TR_COMMIT:
case self::TR_ROLLBACK:
throw new ExceptionSavepoint("stale", ['action' => "rollback", 'index' => $index]);
default:
throw new Exception("unknownSavepointStatus", $this->transStatus[$index]);
}
if($index==$this->transDepth) {
while($this->transDepth > 0 && $this->transStatus[$this->transDepth] > self::TR_PEND) {
array_pop($this->transStatus);
$this->transDepth--;
}
}
if(!$this->transDepth && $this->locked) {
$this->unlock(true);
$this->locked = false;
}
return $out;
} else {
throw new ExceptionSavepoint("invalid", ['action' => "rollback", 'index' => $index]);
}
}
public function prepare(string $query, ...$paramType): Statement {
return $this->prepareArray($query, $paramType);
}
}