bug #33921 [Cache] improve perf of pruning for fs-based adapters (nic…

…olas-grekas)

This PR was merged into the 4.4 branch.

Discussion
----------

[Cache] improve perf of pruning for fs-based adapters

| Q             | A
| ------------- | ---
| Branch?       | 4.4
| Bug fix?      | no
| New feature?  | no
| Deprecations? | no
| Tickets       | Fix #32701
| License       | MIT
| Doc PR        | -

Thank you [Blackfire.io](https://blackfire.io)

https://blackfire.io/profiles/compare/8044c3cf-1541-4a24-9804-5670c63fcb4c/graph

![image](https://user-images.githubusercontent.com/243674/66465435-22f9fc80-ea81-11e9-83fc-2444434a33e6.png)

![image](https://user-images.githubusercontent.com/243674/66465462-2d1bfb00-ea81-11e9-827a-4c0502cb5f4a.png)

Commits
-------

0302b1d [Cache] improve perf of pruning for fs-based adapters

src/Symfony/Component/Cache/Adapter/FilesystemTagAwareAdapter.php

@@ -25,6 +25,7 @@
 class FilesystemTagAwareAdapter extends AbstractTagAwareAdapter implements PruneableInterface
 {
     use FilesystemTrait {
+        doClear as private doClearCache;
         doSave as private doSaveCache;
         doDelete as private doDeleteCache;
     }
@@ -41,6 +42,55 @@ public function __construct(string $namespace = '', int $defaultLifetime = 0, st
         $this->init($namespace, $directory);
     }
 
+    /**
+     * {@inheritdoc}
+     */
+    protected function doClear($namespace)
+    {
+        $ok = $this->doClearCache($namespace);
+
+        if ('' !== $namespace) {
+            return $ok;
+        }
+
+        set_error_handler(static function () {});
+        $chars = '+-ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';
+
+        try {
+            foreach ($this->scanHashDir($this->directory.self::TAG_FOLDER.\DIRECTORY_SEPARATOR) as $dir) {
+                if (rename($dir, $renamed = substr_replace($dir, bin2hex(random_bytes(4)), -8))) {
+                    $dir = $renamed.\DIRECTORY_SEPARATOR;
+                } else {
+                    $dir .= \DIRECTORY_SEPARATOR;
+                    $renamed = null;
+                }
+
+                for ($i = 0; $i < 38; ++$i) {
+                    if (!file_exists($dir.$chars[$i])) {
+                        continue;
+                    }
+                    for ($j = 0; $j < 38; ++$j) {
+                        if (!file_exists($d = $dir.$chars[$i].\DIRECTORY_SEPARATOR.$chars[$j])) {
+                            continue;
+                        }
+                        foreach (scandir($d, SCANDIR_SORT_NONE) ?: [] as $link) {
+                            if ('.' !== $link && '..' !== $link && (null !== $renamed || !realpath($d.\DIRECTORY_SEPARATOR.$link))) {
+                                unlink($d.\DIRECTORY_SEPARATOR.$link);
+                            }
+                        }
+                        null === $renamed ?: rmdir($d);
+                    }
+                    null === $renamed ?: rmdir($dir.$chars[$i]);
+                }
+                null === $renamed ?: rmdir($renamed);
+            }
+        } finally {
+            restore_error_handler();
+        }
+
+        return $ok;
+    }
+
     /**
      * {@inheritdoc}
      */
@@ -111,13 +161,13 @@ protected function doInvalidate(array $tagIds): bool
             set_error_handler(static function () {});
 
             try {
-                if (rename($tagFolder, $renamed = substr_replace($tagFolder, bin2hex(random_bytes(4)), -1))) {
+                if (rename($tagFolder, $renamed = substr_replace($tagFolder, bin2hex(random_bytes(4)), -9))) {
                     $tagFolder = $renamed.\DIRECTORY_SEPARATOR;
                 } else {
                     $renamed = null;
                 }
 
-                foreach (new \RecursiveIteratorIterator(new \RecursiveDirectoryIterator($tagFolder, \FilesystemIterator::SKIP_DOTS | \FilesystemIterator::CURRENT_AS_PATHNAME)) as $itemLink) {
+                foreach ($this->scanHashDir($tagFolder) as $itemLink) {
                     unlink(realpath($itemLink) ?: $itemLink);
                     unlink($itemLink);
                 }

src/Symfony/Component/Cache/Traits/FilesystemCommonTrait.php

@@ -26,7 +26,7 @@ trait FilesystemCommonTrait
     private function init(string $namespace, ?string $directory)
     {
         if (!isset($directory[0])) {
-            $directory = sys_get_temp_dir().'/symfony-cache';
+            $directory = sys_get_temp_dir().\DIRECTORY_SEPARATOR.'symfony-cache';
         } else {
             $directory = realpath($directory) ?: $directory;
         }
@@ -55,12 +55,12 @@ protected function doClear($namespace)
     {
         $ok = true;
 
-        foreach (new \RecursiveIteratorIterator(new \RecursiveDirectoryIterator($this->directory, \FilesystemIterator::SKIP_DOTS)) as $file) {
+        foreach ($this->scanHashDir($this->directory) as $file) {
             if ('' !== $namespace && 0 !== strpos($this->getFileKey($file), $namespace)) {
                 continue;
             }
 
-            $ok = ($file->isDir() || $this->doUnlink($file) || !file_exists($file)) && $ok;
+            $ok = ($this->doUnlink($file) || !file_exists($file)) && $ok;
         }
 
         return $ok;
@@ -123,6 +123,33 @@ private function getFileKey(string $file): string
         return '';
     }
 
+    private function scanHashDir(string $directory): \Generator
+    {
+        if (!file_exists($directory)) {
+            return;
+        }
+
+        $chars = '+-ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';
+
+        for ($i = 0; $i < 38; ++$i) {
+            if (!file_exists($directory.$chars[$i])) {
+                continue;
+            }
+
+            for ($j = 0; $j < 38; ++$j) {
+                if (!file_exists($dir = $directory.$chars[$i].\DIRECTORY_SEPARATOR.$chars[$j])) {
+                    continue;
+                }
+
+                foreach (@scandir($dir, SCANDIR_SORT_NONE) ?: [] as $file) {
+                    if ('.' !== $file && '..' !== $file) {
+                        yield $dir.\DIRECTORY_SEPARATOR.$file;
+                    }
+                }
+            }
+        }
+    }
+
     /**
      * @internal
      */

src/Symfony/Component/Cache/Traits/FilesystemTrait.php

@@ -33,7 +33,7 @@ public function prune()
         $time = time();
         $pruned = true;
 
-        foreach (new \RecursiveIteratorIterator(new \RecursiveDirectoryIterator($this->directory, \FilesystemIterator::SKIP_DOTS), \RecursiveIteratorIterator::LEAVES_ONLY) as $file) {
+        foreach ($this->scanHashDir($this->directory) as $file) {
             if (!$h = @fopen($file, 'rb')) {
                 continue;
             }

src/Symfony/Component/Cache/Traits/PhpFilesTrait.php

@@ -54,7 +54,7 @@ public function prune()
 
         set_error_handler($this->includeHandler);
         try {
-            foreach (new \RecursiveIteratorIterator(new \RecursiveDirectoryIterator($this->directory, \FilesystemIterator::SKIP_DOTS), \RecursiveIteratorIterator::LEAVES_ONLY) as $file) {
+            foreach ($this->scanHashDir($this->directory) as $file) {
                 try {
                     if (\is_array($expiresAt = include $file)) {
                         $expiresAt = $expiresAt[0];