Reduce filesystem operations (#94)

* Reduce filesystem operations

* Updated changelog

* Handle race condition

* typo

* cs

* Handle exception

* cs

Author: Nyholm

Changelog.md

@@ -4,6 +4,10 @@ The change log describes what is "Added", "Removed", "Changed" or "Fixed" betwee
 
 ## UNRELEASED
 
+### Changed
+
+Using `Filesystem::update` instead of `Filesystem::delete` and `Filesystem::write`.
+
 ## 0.3.1
 
 ### Added

FilesystemCachePool.php

@@ -16,6 +16,7 @@
 use Cache\Taggable\TaggableItemInterface;
 use Cache\Taggable\TaggablePoolInterface;
 use Cache\Taggable\TaggablePoolTrait;
+use League\Flysystem\FileExistsException;
 use League\Flysystem\FileNotFoundException;
 use League\Flysystem\Filesystem;
 use Psr\Cache\CacheItemInterface;
@@ -64,19 +65,25 @@ public function setFolder($folder)
      */
     protected function fetchObjectFromCache($key)
     {
-        $file = $this->getFilePath($key);
+        $empty = [false, null, []];
+        $file  = $this->getFilePath($key);
         if (!$this->filesystem->has($file)) {
-            return [false, null, []];
+            return $empty;
+        }
+
+        try {
+            $data = unserialize($this->filesystem->read($file));
+        } catch (FileNotFoundException $e) {
+            return $empty;
         }
 
-        $data = unserialize($this->filesystem->read($file));
         if ($data[0] !== null && time() > $data[0]) {
             foreach ($data[2] as $tag) {
                 $this->removeListItem($this->getTagKey($tag), $key);
             }
             $this->forceClear($key);
 
-            return [false, null, []];
+            return $empty;
         }
 
         return [true, $data[1], $data[2]];
@@ -108,21 +115,31 @@ protected function clearOneObjectFromCache($key)
      */
     protected function storeItemInCache(CacheItemInterface $item, $ttl)
     {
-        $file = $this->getFilePath($item->getKey());
-        if ($this->filesystem->has($file)) {
-            $this->filesystem->delete($file);
-        }
-
         $tags = [];
         if ($item instanceof TaggableItemInterface) {
             $tags = $item->getTags();
         }
 
-        return $this->filesystem->write($file, serialize([
-            ($ttl === null ? null : time() + $ttl),
-            $item->get(),
-            $tags,
-        ]));
+        $data = serialize(
+            [
+                ($ttl === null ? null : time() + $ttl),
+                $item->get(),
+                $tags,
+            ]
+        );
+
+        $file = $this->getFilePath($item->getKey());
+        if ($this->filesystem->has($file)) {
+            // Update file if it exists
+            return $this->filesystem->update($file, $data);
+        }
+
+        try {
+            return $this->filesystem->write($file, $data);
+        } catch (FileExistsException $e) {
+            // To handle issues when/if race conditions occurs, we try to update here.
+            return $this->filesystem->update($file, $data);
+        }
     }
 
     /**