Implement atomic increment/decrement in Cache library
Requested via issue #109
Supersedes PR #241
diff --git a/system/libraries/Cache/drivers/Cache_file.php b/system/libraries/Cache/drivers/Cache_file.php
index 769bd5a..8c99c5e 100644
--- a/system/libraries/Cache/drivers/Cache_file.php
+++ b/system/libraries/Cache/drivers/Cache_file.php
@@ -62,25 +62,13 @@
/**
* Fetch from cache
*
- * @param mixed unique key id
- * @return mixed data on success/false on failure
+ * @param string $id Cache ID
+ * @return mixed Data on success, FALSE on failure
*/
public function get($id)
{
- if ( ! file_exists($this->_cache_path.$id))
- {
- return FALSE;
- }
-
- $data = unserialize(file_get_contents($this->_cache_path.$id));
-
- if ($data['ttl'] > 0 && time() > $data['time'] + $data['ttl'])
- {
- unlink($this->_cache_path.$id);
- return FALSE;
- }
-
- return $data['data'];
+ $data = $this->_get($id);
+ return is_array($data) ? $data['data'] : FALSE;
}
// ------------------------------------------------------------------------
@@ -88,13 +76,13 @@
/**
* Save into cache
*
- * @param string unique key
- * @param mixed data to store
- * @param int length of time (in seconds) the cache is valid
- * - Default is 60 seconds
- * @return bool true on success/false on failure
+ * @param string $id Cache ID
+ * @param mixed $data Data to store
+ * @param int $ttl Time to live in seconds
+ * @param bool $raw Whether to store the raw value (unused)
+ * @return bool TRUE on success, FALSE on failure
*/
- public function save($id, $data, $ttl = 60)
+ public function save($id, $data, $ttl = 60, $raw = FALSE)
{
$contents = array(
'time' => time(),
@@ -127,6 +115,54 @@
// ------------------------------------------------------------------------
/**
+ * Increment a raw value
+ *
+ * @param string $id Cache ID
+ * @param int $offset Step/value to add
+ * @return New value on success, FALSE on failure
+ */
+ public function increment($id, $offset = 1)
+ {
+ $data = $this->_get($id);
+
+ if ($data === FALSE OR ! is_int($data['data']))
+ {
+ return FALSE;
+ }
+
+ $new_value = $data['data'] + $offset;
+ return $this->save($id, $new_value, $data['ttl'])
+ ? $new_value
+ : FALSE;
+ }
+
+ // ------------------------------------------------------------------------
+
+ /**
+ * Decrement a raw value
+ *
+ * @param string $id Cache ID
+ * @param int $offset Step/value to reduce by
+ * @return New value on success, FALSE on failure
+ */
+ public function decrement($id, $offset = 1)
+ {
+ $data = $this->_get($id);
+
+ if ($data === FALSE OR ! is_int($data['data']))
+ {
+ return FALSE;
+ }
+
+ $new_value = $data['data'] - $offset;
+ return $this->save($id, $new_value, $data['ttl'])
+ ? $new_value
+ : FALSE;
+ }
+
+ // ------------------------------------------------------------------------
+
+ /**
* Clean the Cache
*
* @return bool false on failure/true on success
@@ -200,6 +236,34 @@
return is_really_writable($this->_cache_path);
}
+ // ------------------------------------------------------------------------
+
+ /**
+ * Get all data
+ *
+ * Internal method to get all the relevant data about a cache item
+ *
+ * @param string $id Cache ID
+ * @return mixed Data array on success or FALSE on failure
+ */
+ protected function _get($id)
+ {
+ if ( ! file_exists($this->_cache_path.$id))
+ {
+ return FALSE;
+ }
+
+ $data = unserialize(file_get_contents($this->_cache_path.$id));
+
+ if ($data['ttl'] > 0 && time() > $data['time'] + $data['ttl'])
+ {
+ unlink($this->_cache_path.$id);
+ return FALSE;
+ }
+
+ return $data;
+ }
+
}
/* End of file Cache_file.php */