Remove on readUnlock if the caller is the last reader.

This is slower as its another internal mongo write lock is taken on the update, but given most apps read more than write, we don't want to the lock documents to build.

Author: Jonathan Gaillard

src/Locker.php

@@ -87,6 +87,7 @@ public static function readLock(
     public static function readUnlock(\MongoCollection $collection, $id, \MongoId $readerId)
     {
         $collection->update(['_id' => $id], ['$pull' => ['readers' => ['id' => $readerId]]]);
+        $collection->remove(['_id' => $id, 'writing' => false, 'readers' => ['$size' => 0]]);
     }
 
     /**

tests/LockerTest.php

@@ -209,17 +209,7 @@ public function readUnlockEmptyCollection()
         $readerId = Locker::readLock($collection, 'theId', new \MongoDate(time() + 1000));
         Locker::readUnlock($collection, 'theId', $readerId);
 
-        $this->assertSame(1, $collection->count());
-        $expected = [
-            '_id' => 'theId',
-            'readers' => [],
-            'writePending' => false,
-            'writeStaleTs' => null,
-            'writing' => false,
-        ];
-        $actual = $collection->findOne();
-        ksort($actual);
-        $this->assertSame($expected, $actual);
+        $this->assertSame(0, $collection->count());
     }
 
     /**