From 7e7639442fdb4b8e2ac107cc183b899597eb5633 Mon Sep 17 00:00:00 2001
From: Stephen Coakley <me@stephencoakley.com>
Date: Thu, 3 Sep 2015 17:20:58 -0500
Subject: [PATCH] Keep track of PosixSemaphore size & handle cloning

---
 src/Sync/PosixSemaphore.php | 32 ++++++++++++++++++++++++++++++--
 1 file changed, 30 insertions(+), 2 deletions(-)

diff --git a/src/Sync/PosixSemaphore.php b/src/Sync/PosixSemaphore.php
index d786724..1d42ca6 100644
--- a/src/Sync/PosixSemaphore.php
+++ b/src/Sync/PosixSemaphore.php
@@ -21,6 +21,11 @@ class PosixSemaphore implements SemaphoreInterface, \Serializable
      */
     private $key;
 
+    /**
+     * @var int The number of total locks.
+     */
+    private $maxLocks;
+
     /**
      * @var resource A message queue of available locks.
      */
@@ -36,7 +41,12 @@ class PosixSemaphore implements SemaphoreInterface, \Serializable
      */
     public function __construct($maxLocks, $permissions = 0600)
     {
+        if (!is_int($maxLocks) || $maxLocks < 0) {
+            throw new InvalidArgumentError('Max locks must be a non-negative integer.');
+        }
+
         $this->key = abs(crc32(spl_object_hash($this)));
+        $this->maxLocks = $maxLocks;
 
         $this->queue = msg_get_queue($this->key, $permissions);
         if (!$this->queue) {
@@ -59,6 +69,16 @@ class PosixSemaphore implements SemaphoreInterface, \Serializable
         return !is_resource($this->queue) || !msg_queue_exists($this->key);
     }
 
+    /**
+     * Gets the maximum number of locks held by the semaphore.
+     *
+     * @return int The maximum number of locks held by the semaphore.
+     */
+    public function getSize()
+    {
+        return $this->maxLocks;
+    }
+
     /**
      * Gets the access permissions of the semaphore.
      *
@@ -148,7 +168,7 @@ class PosixSemaphore implements SemaphoreInterface, \Serializable
      */
     public function serialize()
     {
-        return serialize($this->key);
+        return serialize([$this->key, $this->maxLocks]);
     }
 
     /**
@@ -159,13 +179,21 @@ class PosixSemaphore implements SemaphoreInterface, \Serializable
     public function unserialize($serialized)
     {
         // Get the semaphore key and attempt to re-connect to the semaphore in memory.
-        $this->key = unserialize($serialized);
+        list($this->key, $this->maxLocks) = unserialize($serialized);
 
         if (msg_queue_exists($this->key)) {
             $this->queue = msg_get_queue($this->key);
         }
     }
 
+    /**
+     * Clones the semaphore, creating a new semaphore with the same size and permissions.
+     */
+    public function __clone()
+    {
+        $this->__construct($this->maxLocks, $this->getPermissions());
+    }
+
     /**
      * Releases a lock from the semaphore.
      *