<?php
/**
* Smarty Internal Plugin
*
* @package Smarty
* @subpackage Cacher
*/
/**
* Smarty Cache Handler Base for Key/Value Storage Implementations
*
* This class implements the functionality required to use simple key/value stores
* for hierarchical cache groups. key/value stores like memcache or APC do not support
* wildcards in keys, therefore a cache group cannot be cleared like "a|*" - which
* is no problem to filesystem and RDBMS implementations.
*
* This implementation is based on the concept of invalidation. While one specific cache
* can be identified and cleared, any range of caches cannot be identified. For this reason
* each level of the cache group hierarchy can have its own value in the store. These values
* are nothing but microtimes, telling us when a particular cache group was cleared for the
* last time. These keys are evaluated for every cache read to determine if the cache has
* been invalidated since it was created and should hence be treated as inexistent.
*
* Although deep hierarchies are possible, they are not recommended. Try to keep your
* cache groups as shallow as possible. Anything up 3-5 parents should be ok. So
* »a|b|c« is a good depth where »a|b|c|d|e|f|g|h|i|j|k« isn't. Try to join correlating
* cache groups: if your cache groups look somewhat like »a|b|$page|$items|$whatever«
* consider using »a|b|c|$page-$items-$whatever« instead.
*
* @package Smarty
* @subpackage Cacher
* @author Rodney Rehm
*/
abstract class Smarty_CacheResource_KeyValueStore extends Smarty_CacheResource
{
/**
* cache for contents
* @var array
*/
protected $contents = array();
/**
* cache for timestamps
* @var array
*/
protected $timestamps = array();
/**
* populate Cached Object with meta data from Resource
*
* @param Smarty_Template_Cached $cached cached object
* @param Smarty_Internal_Template $_template template object
* @return void
*/
public function populate(Smarty_Template_Cached $cached, Smarty_Internal_Template $_template)
{
$cached->filepath = $_template->source->uid
. '#' . $this->sanitize($cached->source->name)
. '#' . $this->sanitize($cached->cache_id)
. '#' . $this->sanitize($cached->compile_id);
$this->populateTimestamp($cached);
}
/**
* populate Cached Object with timestamp and exists from Resource
*
* @param Smarty_Template_Cached $cached cached object
* @return void
*/
public function populateTimestamp(Smarty_Template_Cached $cached)
{
if (!$this->fetch($cached->filepath, $cached->source->name, $cached->cache_id, $cached->compile_id, $content, $timestamp, $cached->source->uid)) {
return;
}
$cached->content = $content;
$cached->timestamp = (int) $timestamp;
$cached->exists = $cached->timestamp;
}
/**
* Read the cached template and process the header
*
* @param Smarty_Internal_Template $_template template object
* @param Smarty_Template_Cached $cached cached object
* @return booelan true or false if the cached content does not exist
*/
public function process(Smarty_Internal_Template $_template, Smarty_Template_Cached $cached=null)
{
if (!$cached) {
$cached = $_template->cached;
}
$content = $cached->content ? $cached->content : null;
$timestamp = $cached->timestamp ? $cached->timestamp : null;
if ($content === null || !$timestamp) {
if (!$this->fetch($_template->cached->filepath, $_template->source->name, $_template->cache_id, $_template->compile_id, $content, $timestamp, $_template->source->uid)) {
return false;
}
}
if (isset($content)) {
$_smarty_tpl = $_template;
eval("?>" . $content);
return true;
}
return false;
}
/**
* Write the rendered template output to cache
*
* @param Smarty_Internal_Template $_template template object
* @param string $content content to cache
* @return boolean success
*/
public function writeCachedContent(Smarty_Internal_Template $_template, $content)
{
$this->addMetaTimestamp($content);
return $this->write(array($_template->cached->filepath => $content), $_template->properties['cache_lifetime']);
}
/**
* Empty cache
*
* {@internal the $exp_time argument is ignored altogether }}
*
* @param Smarty $smarty Smarty object
* @param integer $exp_time expiration time [being ignored]
* @return integer number of cache files deleted [always -1]
* @uses purge() to clear the whole store
* @uses invalidate() to mark everything outdated if purge() is inapplicable
*/
public function clearAll(Smarty $smarty, $exp_time=null)
{
if (!$this->purge()) {
$this->invalidate(null);
}
return -1;
}
/**
* Empty cache for a specific template
*
* {@internal the $exp_time argument is ignored altogether}}
*
* @param Smarty $smarty Smarty object
* @param string $resource_name template name
* @param string $cache_id cache id
* @param string $compile_id compile id
* @param integer $exp_time expiration time [being ignored]
* @return integer number of cache files deleted [always -1]
* @uses buildCachedFilepath() to generate the CacheID
* @uses invalidate() to mark CacheIDs parent chain as outdated
* @uses delete() to remove CacheID from cache
*/
public function clear(Smarty $smarty, $resource_name, $cache_id, $compile_id, $exp_time)
{
$uid = $this->getTemplateUid($smarty, $resource_name, $cache_id, $compile_id);
$cid = $uid . '#' . $this->sanitize($resource_name) . '#' . $this->sanitize($cache_id) . '#' . $this->sanitize($compile_id);
$this->delete(array($cid));
$this->invalidate($cid, $resource_name, $cache_id, $compile_id, $uid);
return -1;
}
/**
* Get template's unique ID
*
* @param Smarty $smarty Smarty object
* @param string $resource_name template name
* @param string $cache_id cache id
* @param string $compile_id compile id
* @return string filepath of cache file
*/
protected function getTemplateUid(Smarty $smarty, $resource_name, $cache_id, $compile_id)
{
$uid = '';
if (isset($resource_name)) {
$tpl = new $smarty->template_class($resource_name, $smarty);
if ($tpl->source->exists) {
$uid = $tpl->source->uid;
}
// remove from template cache
if ($smarty->allow_ambiguous_resources) {
$_templateId = $tpl->source->unique_resource . $tpl->cache_id . $tpl->compile_id;
} else {
$_templateId = $smarty->joined_template_dir . '#' . $resource_name . $tpl->cache_id . $tpl->compile_id;
}
if (isset($_templateId[150])) {
$_templateId = sha1($_templateId);
}
unset($smarty->template_objects[$_templateId]);
}
return $uid;
}
/**
* Sanitize CacheID components
*
* @param string $string CacheID component to sanitize
* @return string sanitized CacheID component
*/
protected function sanitize($string)
{
// some poeple smoke bad weed
$string = trim($string, '|');
if (!$string) {
return null;
}
return preg_replace('#[^\w\|]+#S', '_', $string);
}
/**
* Fetch and prepare a cache object.
*
* @param string $cid CacheID to fetch
* @param string $resource_name template name
* @param string $cache_id cache id
* @param string $compile_id compile id
* @param string $content cached content
* @param integer &$timestamp cached timestamp (epoch)
* @param string $resource_uid resource's uid
* @return boolean success
*/
protected function fetch($cid, $resource_name = null, $cache_id = null, $compile_id = null, &$content = null, &$timestamp = null, $resource_uid = null)
{
$t = $this->read(array($cid));
$content = !empty($t[$cid]) ? $t[$cid] : null;
$timestamp = null;
if ($content && ($timestamp = $this->getMetaTimestamp($content))) {
$invalidated = $this->getLatestInvalidationTimestamp($cid, $resource_name, $cache_id, $compile_id, $resource_uid);
if ($invalidated > $timestamp) {
$timestamp = null;
$content = null;
}
}
return !!$content;
}
/**
* Add current microtime to the beginning of $cache_content
*
* {@internal the header uses 8 Bytes, the first 4 Bytes are the seconds, the second 4 Bytes are the microseconds}}
*
* @param string &$content the content to be cached
*/
protected function addMetaTimestamp(&$content)
{
$mt = explode(" ", microtime());
$ts = pack("NN", $mt[1], (int) ($mt[0] * 100000000));
$content = $ts . $content;
}
/**
* Extract the timestamp the $content was cached
*
* @param string &$content the cached content
* @return float the microtime the content was cached
*/
protected function getMetaTimestamp(&$content)
{
$s = unpack("N", substr($content, 0, 4));
$m = unpack("N", substr($content, 4, 4));
$content = substr($content, 8);
return $s[1] + ($m[1] / 100000000);
}
/**
* Invalidate CacheID
*
* @param string $cid CacheID
* @param string $resource_name template name
* @param string $cache_id cache id
* @param string $compile_id compile id
* @param string $resource_uid source's uid
* @return void
*/
protected function invalidate($cid = null, $resource_name = null, $cache_id = null, $compile_id = null, $resource_uid = null)
{
$now = microtime(true);
$key = null;
// invalidate everything
if (!$resource_name && !$cache_id && !$compile_id) {
$key = 'IVK#ALL';
}
// invalidate all caches by template
else if ($resource_name && !$cache_id && !$compile_id) {
$key = 'IVK#TEMPLATE#' . $resource_uid . '#' . $this->sanitize($resource_name);
}
// invalidate all caches by cache group
else if (!$resource_name && $cache_id && !$compile_id) {
$key = 'IVK#CACHE#' . $this->sanitize($cache_id);
}
// invalidate all caches by compile id
else if (!$resource_name && !$cache_id && $compile_id) {
$key = 'IVK#COMPILE#' . $this->sanitize($compile_id);
}
// invalidate by combination
else {
$key = 'IVK#CID#' . $cid;
}
$this->write(array($key => $now));
}
/**
* Determine the latest timestamp known to the invalidation chain
*
* @param string $cid CacheID to determine latest invalidation timestamp of
* @param string $resource_name template name
* @param string $cache_id cache id
* @param string $compile_id compile id
* @param string $resource_uid source's filepath
* @return float the microtime the CacheID was invalidated
*/
protected function getLatestInvalidationTimestamp($cid, $resource_name = null, $cache_id = null, $compile_id = null, $resource_uid = null)
{
// abort if there is no CacheID
if (false && !$cid) {
return 0;
}
// abort if there are no InvalidationKeys to check
if (!($_cid = $this->listInvalidationKeys($cid, $resource_name, $cache_id, $compile_id, $resource_uid))) {
return 0;
}
// there are no InValidationKeys
if (!($values = $this->read($_cid))) {
return 0;
}
// make sure we're dealing with floats
$values = array_map('floatval', $values);
return max($values);
}
/**
* Translate a CacheID into the list of applicable InvalidationKeys.
*
* Splits "some|chain|into|an|array" into array( '#clearAll#', 'some', 'some|chain', 'some|chain|into', ... )
*
* @param string $cid CacheID to translate
* @param string $resource_name template name
* @param string $cache_id cache id
* @param string $compile_id compile id
* @param string $resource_uid source's filepath
* @return array list of InvalidationKeys
* @uses $invalidationKeyPrefix to prepend to each InvalidationKey
*/
protected function listInvalidationKeys($cid, $resource_name = null, $cache_id = null, $compile_id = null, $resource_uid = null)
{
$t = array('IVK#ALL');
$_name = $_compile = '#';
if ($resource_name) {
$_name .= $resource_uid . '#' . $this->sanitize($resource_name);
$t[] = 'IVK#TEMPLATE' . $_name;
}
if ($compile_id) {
$_compile .= $this->sanitize($compile_id);
$t[] = 'IVK#COMPILE' . $_compile;
}
$_name .= '#';
// some poeple smoke bad weed
$cid = trim($cache_id, '|');
if (!$cid) {
return $t;
}
$i = 0;
while (true) {
// determine next delimiter position
$i = strpos($cid, '|', $i);
// add complete CacheID if there are no more delimiters
if ($i === false) {
$t[] = 'IVK#CACHE#' . $cid;
$t[] = 'IVK#CID' . $_name . $cid . $_compile;
$t[] = 'IVK#CID' . $_name . $_compile;
break;
}
$part = substr($cid, 0, $i);
// add slice to list
$t[] = 'IVK#CACHE#' . $part;
$t[] = 'IVK#CID' . $_name . $part . $_compile;
// skip past delimiter position
$i++;
}
return $t;
}
/**
* Check is cache is locked for this template
*
* @param Smarty $smarty Smarty object
* @param Smarty_Template_Cached $cached cached object
* @return booelan true or false if cache is locked
*/
public function hasLock(Smarty $smarty, Smarty_Template_Cached $cached)
{
$key = 'LOCK#' . $cached->filepath;
$data = $this->read(array($key));
return $data && time() - $data[$key] < $smarty->locking_timeout;
}
/**
* Lock cache for this template
*
* @param Smarty $smarty Smarty object
* @param Smarty_Template_Cached $cached cached object
*/
public function acquireLock(Smarty $smarty, Smarty_Template_Cached $cached)
{
$cached->is_locked = true;
$key = 'LOCK#' . $cached->filepath;
$this->write(array($key => time()), $smarty->locking_timeout);
}
/**
* Unlock cache for this template
*
* @param Smarty $smarty Smarty object
* @param Smarty_Template_Cached $cached cached object
*/
public function releaseLock(Smarty $smarty, Smarty_Template_Cached $cached)
{
$cached->is_locked = false;
$key = 'LOCK#' . $cached->filepath;
$this->delete(array($key));
}
/**
* Read values for a set of keys from cache
*
* @param array $keys list of keys to fetch
* @return array list of values with the given keys used as indexes
*/
abstract protected function read(array $keys);
/**
* Save values for a set of keys to cache
*
* @param array $keys list of values to save
* @param int $expire expiration time
* @return boolean true on success, false on failure
*/
abstract protected function write(array $keys, $expire=null);
/**
* Remove values from cache
*
* @param array $keys list of keys to delete
* @return boolean true on success, false on failure
*/
abstract protected function delete(array $keys);
/**
* Remove *all* values from cache
*
* @return boolean true on success, false on failure
*/
protected function purge()
{
return false;
}
}
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