Improve PostgreSQL advisory lock key hashing

src/mutex/PgAdvisoryLockMutex.php

@@ -4,16 +4,15 @@
 
 namespace malkusch\lock\mutex;
 
+use malkusch\lock\util\LockUtil;
+
 class PgAdvisoryLockMutex extends LockMutex
 {
  /** @var \PDO */
  private $pdo;
 
- /** @var int */
- private $key1;
-
- /** @var int */
- private $key2;
+ /** @var array{int, int} */
+ private array $key;
 
  /**
  * @throws \RuntimeException
@@ -22,32 +21,33 @@ public function __construct(\PDO $PDO, string $name)
  {
  $this->pdo = $PDO;
 
- $hashed_name = hash('sha256', $name, true);
+ [$keyBytes1, $keyBytes2] = str_split(md5(LockUtil::getInstance()->getKeyPrefix() . ':' . $name, true), 4);
+
+ // https://github.com/php/php-src/issues/17068
+ $unpackToSignedIntLeFx = static function (string $v) {
+ $unpacked = unpack('va/Cb/cc', $v);
 
- [$bytes1, $bytes2] = str_split($hashed_name, 4);
+ return $unpacked['a'] | ($unpacked['b'] << 16) | ($unpacked['c'] << 24);
+ };
 
- $this->key1 = unpack('i', $bytes1)[1];
- $this->key2 = unpack('i', $bytes2)[1];
+ $this->key = [
+ $unpackToSignedIntLeFx($keyBytes1),
+ $unpackToSignedIntLeFx($keyBytes2),
+ ];
  }
 
  #[\Override]
  protected function lock(): void
  {
  $statement = $this->pdo->prepare('SELECT pg_advisory_lock(?, ?)');
 
- $statement->execute([
- $this->key1,
- $this->key2,
- ]);
+ $statement->execute($this->key);
  }
 
  #[\Override]
  protected function unlock(): void
  {
  $statement = $this->pdo->prepare('SELECT pg_advisory_unlock(?, ?)');
- $statement->execute([
- $this->key1,
- $this->key2,
- ]);
+ $statement->execute($this->key);
  }
 }

tests/mutex/PgAdvisoryLockMutexTest.php

@@ -24,7 +24,7 @@ protected function setUp(): void
 
  $this->pdo = $this->createMock(\PDO::class);
 
- $this->mutex = new PgAdvisoryLockMutex($this->pdo, 'test');
+ $this->mutex = new PgAdvisoryLockMutex($this->pdo, 'test-one-negative-key');
  }
 
  private function isPhpunit9x(): bool
@@ -52,11 +52,14 @@ public function testAcquireLock(): void
  }
 
  foreach ($arguments as $v) {
+ self::assertLessThan(1 << 32, $v);
+ self::assertGreaterThanOrEqual(-(1 << 32), $v);
  self::assertIsInt($v);
  }
 
  return true;
- })
+ }),
+ [533558444, -1716795572]
  ));
 
  \Closure::bind(static fn ($mutex) => $mutex->lock(), null, PgAdvisoryLockMutex::class)($this->mutex);
@@ -83,12 +86,13 @@ public function testReleaseLock(): void
 
  foreach ($arguments as $v) {
  self::assertLessThan(1 << 32, $v);
- self::assertGreaterThan(-(1 << 32), $v);
+ self::assertGreaterThanOrEqual(-(1 << 32), $v);
  self::assertIsInt($v);
  }
 
  return true;
- })
+ }),
+ [533558444, -1716795572]
  ));
 
  \Closure::bind(static fn ($mutex) => $mutex->unlock(), null, PgAdvisoryLockMutex::class)($this->mutex);