<?php

/**

 * Smarty Internal Plugin

 *

 * @package    Smarty

 * @subpackage Cacher

 */

/**

 * Cache Handler API

 *

 * @package    Smarty

 * @subpackage Cacher

 * @author     Rodney Rehm

 */

abstract class Smarty_CacheResource_Custom extends Smarty_CacheResource {

    /**

     * fetch cached content and its modification time from data source

     *

     * @param  string $id unique cache content identifier

     * @param  string $name template name

     * @param  string $cache_id cache id

     * @param  string $compile_id compile id

     * @param  string $content cached content

     * @param  integer $mtime cache modification timestamp (epoch)

     *

     * @return void

     */

    abstract protected function fetch($id, $name, $cache_id, $compile_id, &$content, &$mtime);

    /**

     * Fetch cached content's modification timestamp from data source

     * {@internal implementing this method is optional.

     *  Only implement it if modification times can be accessed faster than loading the complete cached content.}}

     *

     * @param  string $id unique cache content identifier

     * @param  string $name template name

     * @param  string $cache_id cache id

     * @param  string $compile_id compile id

     *

     * @return integer|boolean timestamp (epoch) the template was modified, or false if not found

     */

    protected function fetchTimestamp($id, $name, $cache_id, $compile_id) {

        return null;

    }

    /**

     * Save content to cache

     *

     * @param  string $id unique cache content identifier

     * @param  string $name template name

     * @param  string $cache_id cache id

     * @param  string $compile_id compile id

     * @param  integer|null $exp_time seconds till expiration or null

     * @param  string $content content to cache

     *

     * @return boolean      success

     */

    abstract protected function save($id, $name, $cache_id, $compile_id, $exp_time, $content);

    /**

     * Delete content from cache

     *

     * @param  string $name template name

     * @param  string $cache_id cache id

     * @param  string $compile_id compile id

     * @param  integer|null $exp_time seconds till expiration time in seconds or null

     *

     * @return integer      number of deleted caches

     */

    abstract protected function delete($name, $cache_id, $compile_id, $exp_time);

    /**

     * 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) {

        $_cache_id = isset($cached->cache_id) ? preg_replace('![^\w\|]+!', '_', $cached->cache_id) : null;

        $_compile_id = isset($cached->compile_id) ? preg_replace('![^\w\|]+!', '_', $cached->compile_id) : null;

        $path = $cached->source->filepath . $_cache_id . $_compile_id;

        $cached->filepath = sha1($path);

        if ($_template->smarty->cache_locking) {

            $cached->lock_id = sha1('lock.' . $path);

        }

        $this->populateTimestamp($cached);

    }

    /**

     * populate Cached Object with timestamp and exists from Resource

     *

     * @param Smarty_Template_Cached $cached

     *

     * @return void

     */

    public function populateTimestamp(Smarty_Template_Cached $cached) {

        $mtime = $this->fetchTimestamp($cached->filepath, $cached->source->name, $cached->cache_id, $cached->compile_id);

        if ($mtime !== null) {

            $cached->timestamp = $mtime;

            $cached->exists = !!$cached->timestamp;

            return;

        }

        $timestamp = null;

        $this->fetch($cached->filepath, $cached->source->name, $cached->cache_id, $cached->compile_id, $cached->content, $timestamp);

        $cached->timestamp = isset($timestamp) ? $timestamp : false;

        $cached->exists = !!$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 boolean                 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) {

            $this->fetch(

                $_template->cached->filepath,

                $_template->source->name,

                $_template->cache_id,

                $_template->compile_id,

                $content,

                $timestamp

            );

        }

        if (isset($content)) {

            /** @var Smarty_Internal_Template $_smarty_tpl

             * used in evaluated code

             */

            $_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) {

        return $this->save(

            $_template->cached->filepath,

            $_template->source->name,

            $_template->cache_id,

            $_template->compile_id,

            $_template->properties['cache_lifetime'],

            $content

        );

    }

    /**

     * Read cached template from cache

     *

     * @param  Smarty_Internal_Template $_template template object

     *

     * @return string  content

     */

    public function readCachedContent(Smarty_Internal_Template $_template) {

        $content = $_template->cached->content ? $_template->cached->content : null;

        $timestamp = null;

        if ($content === null) {

            $timestamp = null;

            $this->fetch(

                $_template->cached->filepath,

                $_template->source->name,

                $_template->cache_id,

                $_template->compile_id,

                $content,

                $timestamp

            );

        }

        if (isset($content)) {

            return $content;

        }

        return false;

    }

    /**

     * Empty cache

     *

     * @param  Smarty $smarty Smarty object

     * @param  integer $exp_time expiration time (number of seconds, not timestamp)

     *

     * @return integer number of cache files deleted

     */

    public function clearAll(Smarty $smarty, $exp_time = null) {

        $this->cache = array();

        return $this->delete(null, null, null, $exp_time);

    }

    /**

     * Empty cache for a specific template

     *

     * @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 (number of seconds, not timestamp)

     *

     * @return integer number of cache files deleted

     */

    public function clear(Smarty $smarty, $resource_name, $cache_id, $compile_id, $exp_time) {

        $this->cache = array();

        $cache_name = null;

        if (isset($resource_name)) {

            $_save_stat = $smarty->caching;

            $smarty->caching = true;

            $tpl = new $smarty->template_class($resource_name, $smarty);

            $smarty->caching = $_save_stat;

            if ($tpl->source->exists) {

                $cache_name = $tpl->source->name;

            } else {

                return 0;

            }

            // 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]);

            // template object no longer needed

            unset($tpl);

        }

        return $this->delete($cache_name, $cache_id, $compile_id, $exp_time);

    }

    /**

     * Check is cache is locked for this template

     *

     * @param  Smarty $smarty Smarty object

     * @param  Smarty_Template_Cached $cached cached object

     *

     * @return boolean               true or false if cache is locked

     */

    public function hasLock(Smarty $smarty, Smarty_Template_Cached $cached) {

        $id = $cached->lock_id;

        $name = $cached->source->name . '.lock';

        $mtime = $this->fetchTimestamp($id, $name, $cached->cache_id, $cached->compile_id);

        if ($mtime === null) {

            $this->fetch($id, $name, $cached->cache_id, $cached->compile_id, $content, $mtime);

        }

        return $mtime && ($t = time()) - $mtime < $smarty->locking_timeout;

    }

    /**

     * Lock cache for this template

     *

     * @param Smarty $smarty Smarty object

     * @param Smarty_Template_Cached $cached cached object

     *

     * @return bool|void

     */

    public function acquireLock(Smarty $smarty, Smarty_Template_Cached $cached) {

        $cached->is_locked = true;

        $id = $cached->lock_id;

        $name = $cached->source->name . '.lock';

        $this->save($id, $name, $cached->cache_id, $cached->compile_id, $smarty->locking_timeout, '');

    }

    /**

     * Unlock cache for this template

     *

     * @param Smarty $smarty Smarty object

     * @param Smarty_Template_Cached $cached cached object

     *

     * @return bool|void

     */

    public function releaseLock(Smarty $smarty, Smarty_Template_Cached $cached) {

        $cached->is_locked = false;

        $name = $cached->source->name . '.lock';

        $this->delete($name, $cached->cache_id, $cached->compile_id, null);

    }

}