[8.x] Add lock support for file and null cache drivers

src/Illuminate/Cache/CacheLock.php

@@ -0,0 +1,85 @@
+<?php
+
+namespace Illuminate\Cache;
+
+class CacheLock extends Lock
+{
+    /**
+     * The cache store implementation.
+     *
+     * @var \Illuminate\Contracts\Cache\Store
+     */
+    protected $store;
+
+    /**
+     * Create a new lock instance.
+     *
+     * @var \Illuminate\Contracts\Cache\Store
+     * @param  string  $name
+     * @param  int  $seconds
+     * @param  string|null  $owner
+     * @return void
+     */
+    public function __construct($store, $name, $seconds, $owner = null)
+    {
+        parent::__construct($name, $seconds, $owner);
+
+        $this->store = $store;
+    }
+
+    /**
+     * Attempt to acquire the lock.
+     *
+     * @return bool
+     */
+    public function acquire()
+    {
+        if (method_exists($this->store, 'add') && $this->seconds > 0) {
+            return $this->store->add(
+                $this->name, $this->owner, $this->seconds
+            );
+        }
+
+        if (! is_null($this->store->get($this->name))) {
+            return false;
+        }
+
+        return ($this->seconds > 0)
+                ? $this->store->put($this->name, $this->owner, $this->seconds)
+                : $this->store->forever($this->name, $this->owner, $this->seconds);
+    }
+
+    /**
+     * Release the lock.
+     *
+     * @return bool
+     */
+    public function release()
+    {
+        if ($this->isOwnedByCurrentProcess()) {
+            return $this->store->forget($this->name);
+        }
+
+        return false;
+    }
+
+    /**
+     * Releases this lock in disregard of ownership.
+     *
+     * @return void
+     */
+    public function forceRelease()
+    {
+        $this->store->forget($this->name);
+    }
+
+    /**
+     * Returns the owner value written into the driver for this lock.
+     *
+     * @return mixed
+     */
+    protected function getCurrentOwner()
+    {
+        return $this->store->get($this->name);
+    }
+}

src/Illuminate/Cache/FileStore.php

@@ -3,13 +3,15 @@
 namespace Illuminate\Cache;
 
 use Exception;
+use Illuminate\Contracts\Cache\LockProvider;
 use Illuminate\Contracts\Cache\Store;
+use Illuminate\Contracts\Filesystem\LockTimeoutException;
 use Illuminate\Filesystem\Filesystem;
 use Illuminate\Support\InteractsWithTime;
 
-class FileStore implements Store
+class FileStore implements Store, LockProvider
 {
-    use InteractsWithTime, RetrievesMultipleKeys;
+    use InteractsWithTime, RetrievesMultipleKeys, HasCacheLock;
 
     /**
      * The Illuminate Filesystem instance.
@@ -83,6 +85,45 @@ public function put($key, $value, $seconds)
         return false;
     }
 
+    /**
+     * Store an item in the cache if the key doesn't exist.
+     *
+     * @param  string  $key
+     * @param  mixed  $value
+     * @param  int  $seconds
+     * @return bool
+     */
+    public function add($key, $value, $seconds)
+    {
+        $this->ensureCacheDirectoryExists($path = $this->path($key));
+
+        $file = $this->files->newFileForReadWrite($path);
+
+        try {
+            $file->getExclusiveLock();
+        } catch (LockTimeoutException $e) {
+            $file->close();
+
+            return false;
+        }
+
+        $expire = $file->read(10);
+
+        if (empty($expire) || $this->currentTime() >= $expire) {
+            $file->truncate()
+                ->write($this->expiration($seconds).serialize($value))
+                ->close();
+
+            $this->ensureFileHasCorrectPermissions($path);
+
+            return true;
+        }
+
+        $file->close();
+
+        return false;
+    }
+
     /**
      * Create the file cache directory if necessary.
      *

src/Illuminate/Cache/HasCacheLock.php

@@ -0,0 +1,31 @@
+<?php
+
+namespace Illuminate\Cache;
+
+trait HasCacheLock
+{
+    /**
+     * Get a lock instance.
+     *
+     * @param  string  $name
+     * @param  int  $seconds
+     * @param  string|null  $owner
+     * @return \Illuminate\Contracts\Cache\Lock
+     */
+    public function lock($name, $seconds = 0, $owner = null)
+    {
+        return new CacheLock($this, $name, $seconds, $owner);
+    }
+
+    /**
+     * Restore a lock instance using the owner identifier.
+     *
+     * @param  string  $name
+     * @param  string  $owner
+     * @return \Illuminate\Contracts\Cache\Lock
+     */
+    public function restoreLock($name, $owner)
+    {
+        return $this->lock($name, 0, $owner);
+    }
+}

src/Illuminate/Cache/NoLock.php

@@ -0,0 +1,46 @@
+<?php
+
+namespace Illuminate\Cache;
+
+class NoLock extends Lock
+{
+    /**
+     * Attempt to acquire the lock.
+     *
+     * @return bool
+     */
+    public function acquire()
+    {
+        return true;
+    }
+
+    /**
+     * Release the lock.
+     *
+     * @return bool
+     */
+    public function release()
+    {
+        return true;
+    }
+
+    /**
+     * Releases this lock in disregard of ownership.
+     *
+     * @return void
+     */
+    public function forceRelease()
+    {
+        //
+    }
+
+    /**
+     * Returns the owner value written into the driver for this lock.
+     *
+     * @return mixed
+     */
+    protected function getCurrentOwner()
+    {
+        return $this->owner;
+    }
+}

src/Illuminate/Cache/NullStore.php

@@ -2,7 +2,9 @@
 
 namespace Illuminate\Cache;
 
-class NullStore extends TaggableStore
+use Illuminate\Contracts\Cache\LockProvider;
+
+class NullStore extends TaggableStore implements LockProvider
 {
     use RetrievesMultipleKeys;
 
@@ -96,4 +98,29 @@ public function getPrefix()
     {
         return '';
     }
+
+    /**
+     * Get a lock instance.
+     *
+     * @param  string  $name
+     * @param  int  $seconds
+     * @param  string|null  $owner
+     * @return \Illuminate\Contracts\Cache\Lock
+     */
+    public function lock($name, $seconds = 0, $owner = null)
+    {
+        return new NoLock($name, $seconds, $owner);
+    }
+
+    /**
+     * Restore a lock instance using the owner identifier.
+     *
+     * @param  string  $name
+     * @param  string  $owner
+     * @return \Illuminate\Contracts\Cache\Lock
+     */
+    public function restoreLock($name, $owner)
+    {
+        return $this->lock($name, 0, $owner);
+    }
 }

src/Illuminate/Contracts/Filesystem/LockTimeoutException.php

@@ -0,0 +1,10 @@
+<?php
+
+namespace Illuminate\Contracts\Filesystem;
+
+use Exception;
+
+class LockTimeoutException extends Exception
+{
+    //
+}