Added lock and unlock methods to FilesystemService for resource handling

Author: andrey-helldar

src/Services/FilesystemService.php

@@ -15,7 +15,10 @@
 
 use function dirname;
 use function fclose;
+use function fflush;
+use function flock;
 use function fopen;
+use function ftruncate;
 use function fwrite;
 use function is_resource;
 use function microtime;
@@ -43,6 +46,8 @@ public function createDraft(string $filename) // @pest-ignore-type
                 // @codeCoverageIgnoreEnd
             }
 
+            $this->lock($resource);
+
             return $resource;
             // @codeCoverageIgnoreStart
         } catch (Throwable $e) {
@@ -70,6 +75,7 @@ public function release($resource, string $path): void // @pest-ignore-type
     {
         $temp = $this->getMetaPath($resource);
 
+        $this->unlock($resource);
         $this->close($resource);
 
         if ($this->file->exists($path)) {
@@ -132,4 +138,27 @@ protected function getMetaPath($file): string
 
         return $meta['uri'] ?? throw new ResourceMetaException;
     }
+
+    /**
+     * @param  resource  $resource
+     */
+    protected function lock($resource): void // @pest-ignore-type
+    {
+        if (! flock($resource, LOCK_EX)) {
+            // @codeCoverageIgnoreStart
+            throw new RuntimeException('Resource lock error. The resource may be in use by another process.');
+            // @codeCoverageIgnoreEnd
+        }
+
+        ftruncate($resource, 0);
+    }
+
+    /**
+     * @param  resource  $resource
+     */
+    protected function unlock($resource): void // @pest-ignore-type
+    {
+        fflush($resource);
+        flock($resource, LOCK_UN);
+    }
 }