views/template_loader.php

   1 <?php
   2 // Hoplite
   3 // Copyright (c) 2011 Blue Static
   4 //
   5 // This program is free software: you can redistribute it and/or modify it
   6 // under the terms of the GNU General Public License as published by the Free
   7 // Software Foundation, either version 3 of the License, or any later version.
   8 //
   9 // This program is distributed in the hope that it will be useful, but WITHOUT
  10 // ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11 // FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  12 // more details.
  13 //
  14 // You should have received a copy of the GNU General Public License along with
  15 // this program.  If not, see <http://www.gnu.org/licenses/>.
  16
  17 namespace hoplite\views;
  18
  19 /*!
  20   This class knows how to load and cache templates to the file system.
  21 */
  22 class TemplateLoader
  23 {
  24   /*! @var TemplateLoader Singleton instance */
  25   static private $instance = NULL;
  26
  27   /*! @var string Base path for loading the template file. Use %s to indicate
  28                   where the name (passed to the constructor) should be
  29                   substituted.
  30   */
  31   protected $template_path = '%s.tpl';
  32
  33   /*! @var string The cache path for templates. Unlike |$template_path|, this
  34                   should only be a path, to which the cached template name will
  35                   be appended. This should not end with a trailing slash.
  36   */
  37   protected $cache_path = '/tmp/phalanx_views';
  38
  39   /*! @var string A header to put at the beginning of each cached template file,
  40                   common for setting include paths or cache debug information.
  41   */
  42   protected $cache_prefix = '';
  43
  44   /*! @var array An array of Template objects, keyed by the template name. */
  45   protected $cache = array();
  46
  47   /*! Gets the singleton instance. */
  48   static public function GetInstance()
  49   {
  50     if (!self::$instance)
  51       self::$instance = new __class__();
  52     return self::$instance();
  53   }
  54   /*! Sets the singleton instance. */
  55   static public function SetInstance($instance) { self::$instance = $instance; }
  56
  57   /*! Accessors */
  58   public function set_template_path($path) { $this->$template_path = $path; }
  59   function template_path() { return $this->$template_path; }
  60
  61   public function set_cache_path($path) { $this->$cache_path = $path; }
  62   public function cache_path() { return $this->$cache_path; }
  63
  64   /*!
  65     Loads a template from a file, creates a Template object, and returns a copy
  66     of that object.
  67
  68     @param string Template name, with wich the template plath is formatted.
  69
  70     @return Template Clone of the cached template.
  71   */
  72   public function Load($name)
  73   {
  74     // First check the memory cache.
  75     if (isset($this->cache[$name]))
  76       return clone $this->cache[$name];
  77
  78     // Then check the filesystem cache.
  79     $template = $this->_LoadIfCached($name);
  80     if ($template) {
  81       $this->cache[$name] = $template;
  82       return clone $template;
  83     }
  84
  85     // Finally, parse and cache the template.
  86     $template = $this->_Cache($name);
  87     $this->cache[$name] = $template;
  88     return clone $template;
  89   }
  90
  91   /*!
  92     Loads a cached filesystem template if it is up-to-date.
  93
  94     @param string Template name
  95
  96     @return Template|NULL
  97   */
  98   protected function _LoadIfCached($name)
  99   {
 100     $cache_path = $this->_CachePath($name);
 101     $tpl_path   = $this->_TemplatePath($name);
 102
 103     // Make sure the cached file exists and hasn't gotten out-of-date.
 104     if (!file_exists($cache_path) || filemtime($cache_path) < filemtime($tpl_path)) {
 105       return NULL;
 106
 107     // Load the contents of the cache.
 108     $data = @file_get_contents($cache_path);
 109     if ($data === FALSE)
 110       return NULL;
 111
 112     return Template::NewWithData($data);
 113   }
 114
 115   /*!
 116     Loads a raw template from the file system, stores the compiled template in
 117     the file system, and returns a new template object with that data.
 118
 119     @param string Template name.
 120
 121     @return Template
 122   */
 123   protected function _Cache($name)
 124   {
 125     $cache_path = $this->_CachePath($name);
 126     $tpl_path   = $this->_TemplatePath($name);
 127
 128     $data = @file_get_contents($tpl_path);
 129     if ($data === FALSE)
 130       throw new TemplateLoaderException('Could not load template ' . $this->template_name);
 131
 132     $template = Template::NewWithCompiledData($data);
 133
 134     // Cache the file.
 135     if (!file_put_contents($cache_path, $this->cache_prefix . $template->template()))
 136       throw new TemplateLoaderException('Could not cache ' . $this->template_name . ' to ' . $cache_path);
 137   }
 138
 139   /*! Returns the template path for a given template name. */
 140   protected function _TemplatePath($name)
 141   {
 142     return sprintf($this->template_path, $name);
 143   }
 144
 145   /*! Returns the cache path for a given template name. */
 146   protected function _CachePath($name)
 147   {
 148     return self::$cache_path . '/' . $name . '.phpi';
 149   }
 150 }
 151
 152 class TemplateLoaderException extends \Exception {}