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   1  <?php
   2  
   3  /**
   4   * @file
   5   * Hooks provided by the Chaos Tool Suite.
   6   *
   7   * This file is divided into static hooks (hooks with string literal names) and
   8   * dynamic hooks (hooks with pattern-derived string names).
   9   */
  10  
  11  /**
  12   * @addtogroup hooks
  13   * @{
  14   */
  15  
  16  /**
  17   * This hook is used to inform the CTools plugin system about the location of a
  18   * directory that should be searched for files containing plugins of a
  19   * particular type. CTools invokes this same hook for all plugins, using the
  20   * two passed parameters to indicate the specific type of plugin for which it
  21   * is searching.
  22   *
  23   * The $plugin_type parameter is self-explanatory - it is the string name of the
  24   * plugin type (e.g., Panels' 'layouts' or 'styles'). The $owner parameter is
  25   * necessary because CTools internally namespaces plugins by the module that
  26   * owns them. This is an extension of Drupal best practices on avoiding global
  27   * namespace pollution by prepending your module name to all its functions.
  28   * Consequently, it is possible for two different modules to create a plugin
  29   * type with exactly the same name and have them operate in harmony. In fact,
  30   * this system renders it impossible for modules to encroach on other modules'
  31   * plugin namespaces.
  32   *
  33   * Given this namespacing, it is important that implementations of this hook
  34   * check BOTH the $owner and $plugin_type parameters before returning a path.
  35   * If your module does not implement plugins for the requested module/plugin
  36   * combination, it is safe to return nothing at all (or NULL). As a convenience,
  37   * it is also safe to return a path that does not exist for plugins your module
  38   * does not implement - see form 2 for a use case.
  39   *
  40   * Note that modules implementing a plugin also must implement this hook to
  41   * instruct CTools as to the location of the plugins. See form 3 for a use case.
  42   *
  43   * The conventional structure to return is "plugins/$plugin_type" - that is, a
  44   * 'plugins' subdirectory in your main module directory, with individual
  45   * directories contained therein named for the plugin type they contain.
  46   *
  47   * @param string $owner
  48   *   The system name of the module owning the plugin type for which a base
  49   *   directory location is being requested.
  50   * @param string $plugin_type
  51   *   The name of the plugin type for which a base directory is being requested.
  52   * @return string
  53   *   The path where CTools' plugin system should search for plugin files,
  54   *   relative to your module's root. Omit leading and trailing slashes.
  55   */
  56  function hook_ctools_plugin_directory($owner, $plugin_type) {
  57    // Form 1 - for a module implementing only the 'content_types' plugin owned
  58    // by CTools, this would cause the plugin system to search the
  59    // <moduleroot>/plugins/content_types directory for .inc plugin files.
  60    if ($owner == 'ctools' && $plugin_type == 'content_types') {
  61      return 'plugins/content_types';
  62    }
  63  
  64    // Form 2 - if your module implements only Panels plugins, and has 'layouts'
  65    // and 'styles' plugins but no 'cache' or 'display_renderers', it is OK to be
  66    // lazy and return a directory for a plugin you don't actually implement (so
  67    // long as that directory doesn't exist). This lets you avoid ugly in_array()
  68    // logic in your conditional, and also makes it easy to add plugins of those
  69    // types later without having to change this hook implementation.
  70    if ($owner == 'panels') {
  71      return "plugins/$plugin_type";
  72    }
  73  
  74    // Form 3 - CTools makes no assumptions about where your plugins are located,
  75    // so you still have to implement this hook even for plugins created by your
  76    // own module.
  77    if ($owner == 'mymodule') {
  78      // Yes, this is exactly like Form 2 - just a different reasoning for it.
  79      return "plugins/$plugin_type";
  80    }
  81    // Finally, if nothing matches, it's safe to return nothing at all (or NULL).
  82  }
  83  
  84  /**
  85   * Alter the available functions to be used in ctools math expression api.
  86   *
  87   * One usecase would be to create your own function in your module and
  88   * allow to use it in the math expression api.
  89   *
  90   * @param $functions
  91   *    An array which has the functions as value.
  92   */
  93  function hook_ctools_math_expression_functions_alter(&$functions) {
  94    // Allow to convert from degrees to radiant.
  95    $functions[] = 'deg2rad';
  96  }
  97  
  98  /**
  99   * @} End of "addtogroup hooks".
 100   */