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<?php
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// $Id: handler.module,v 1.13 2008/10/27 00:45:37 crell Exp $
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/**
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* @file
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* The handler module core routines.
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*
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* The handler module provides a mechanism for modules to create and register
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* handler objects. Other modules may then request the appropriate handler
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* for a given context, which will be returned as an object that may be invoked.
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*/
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/**
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* Include our additional libraries.
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*
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* These must be included before any hooks run, as some init hooks may depend
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* on them.
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*/
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require_once(drupal_get_path('module', 'handler') .'/handler.environment.inc');
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require_once(drupal_get_path('module', 'handler') .'/handler.classes.inc');
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/**
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* Implementation of hook_init().
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*/
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function handler_init() {
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handler_rebuild();
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}
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/**
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* Implementation of hook_flush_caches().
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*/
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function handler_flush_caches() {
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handler_rebuild();
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}
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/**
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* Rebuild the handler and slot registries.
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*/
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function handler_rebuild() {
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$targets = handler_slot_build();
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$handlers = handler_handler_build();
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handler_lookup_build();
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}
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/**
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* Rebuild the lookup table used for handler mapping.
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*
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*/
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function handler_lookup_build() {
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$target_order = variable_get('handler_slot_targets', array());
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// Now go through all the saved attachment directives and build out the lookup table.
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$result = db_query("SELECT slot_id, handler_id, targets FROM {handler_attachments}");
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db_query("DELETE FROM {handler_lookup}");
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while ($record = db_fetch_object($result)) {
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$record->targets = unserialize($record->targets);
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$fields = array(
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'slot' => $record->slot_id,
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'handler' => $record->handler_id,
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'specificity' => count($record->targets),
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);
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foreach ($record->targets as $target => $value) {
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// The target order array tracks the mapping of target key to db field.
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$fields[$target_order[$record->slot_id][$target]] = $value;
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}
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// Build the query. I want the D7 query builder! :-(
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$query_fields = implode(',', array_keys($fields));
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$placeholders = implode(',', array_fill(0, count($fields), "'%s'"));
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$values = array();
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foreach ($fields as $value) {
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$values[] = "'{$value}'";
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}
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// Insert this lookup record into the table.
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db_query("INSERT INTO {handler_lookup} ({$query_fields}) VALUES ({$placeholders})", $values);
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}
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}
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/**
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* Rebuild the handler info registry.
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*
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* @return
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* The array of handlers just defined.
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*/
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function handler_handler_build() {
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$handlers = module_invoke_all('handler_info');
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// Set default values, to avoid NULL issues if nothing else.
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foreach ($handlers as $slot => $handler_info) {
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foreach ($handler_info as $handler => $info) {
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$handlers[$slot][$handler] += handler_handler_defaults();
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}
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}
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// Let other modules alter the handler registry if needed.
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drupal_alter('handler_info', $handlers);
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// Don't do the deletion until after we've gotten the new data. That reduces
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// the potential race condition window.
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db_query('DELETE FROM {handler_info}');
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// Build the handler data.
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foreach ($handlers as $slot => $handler_info) {
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foreach ($handler_info as $handler => $info) {
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db_query("INSERT INTO {handler_info} (handler, slot, title, class, description)
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VALUES ('%s', '%s', '%s', '%s', '%s')",
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array($handler, $slot, $info['title'], $info['class'], $info['description'])
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);
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}
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}
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return $handlers ;
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}
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/**
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* Rebuild the handler slot info registry.
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*
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* @return
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* The array of slots just declared.
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*/
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function handler_slot_build() {
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$slots = module_invoke_all('handler_slot_info');
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// Set default values, to avoid NULL issues if nothing else.
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foreach ($slots as $slot => $info) {
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$slots[$slot] += handler_slot_defaults();
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}
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// Let other modules alter the handler target registry if needed.
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drupal_alter('handler_slot_info', $slots);
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// Don't do the deletion until after we've gotten the new data. That reduces
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// the potential race condition window.
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db_query('DELETE FROM {handler_slot_info}');
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$target_order = array();
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// Build the target data.
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foreach ($slots as $slot => $info) {
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db_query("INSERT INTO {handler_slot_info} (slot, title, interface, factory, default_handler, targets, description)
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VALUES ('%s', '%s', '%s', '%s', '%s', '%s', '%s')",
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array($slot, $info['title'], $info['interface'], $info['factory'], $info['default_handler'], serialize($info['targets']), $info['description'])
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);
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// Determine the order of all possible targets, as this will be the order
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// used in the database.
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$targets = array_keys($info['targets']);
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ksort($targets);
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$i = 1;
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foreach ($targets as $target) {
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$target_order[$slot][$target] = 't'. $i++;
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}
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}
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variable_set('handler_slot_targets', $target_order);
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return $slots;
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}
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/**
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* Define various default values for handler slots.
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*
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* @return
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* The default "empty" slot definition.
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*/
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function handler_slot_defaults() {
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return array(
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'slot' => '',
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'title' => '',
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'interface' => 'HandlerInterface',
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'factory' => 'handler_factory_generic',
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'default_handler' => 'default',
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'targets' => array(),
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'description' => '',
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);
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}
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/**
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* Define various default values for handlers.
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*
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* @return
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* The default "empty" handler definition.
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*/
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function handler_handler_defaults() {
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return array(
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'handler' => '',
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'slot' => '',
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'title' => '',
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'class' => '',
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'description' => '',
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);
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}
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/**
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* Main handler entry-point.
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*
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* This function should be called in most instances in place of a factory
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* function. It will automatically route the request to the appropriate
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* factory.
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*
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* @param $slot_id
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* The internal ID of the slot for which we want to retrieve a handler.
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* @param $options
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* The options array determines which handler object should be used, depending
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* on the current configuration.
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* @return
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* The handler object required.
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*/
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function handler($slot_id, $options = array()) {
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$function = handler_get_factory($slot_id);
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if (function_exists($function)) {
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return $function($options, $slot_id);
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}
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return NULL;
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}
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/**
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* Returns the factory function for a given target.
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*
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* If no factory is defined or the function does not exist, a generic
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* factory is returned instead.
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*
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* @param $slot_id
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* The internal ID of the target.
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* @return
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* The name of the factory function as a string.
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*/
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function handler_get_factory($slot_id) {
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$slot = handler_slot_load($slot_id);
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return ($slot->factory && function_exists($slot->factory)) ? $slot->factory : 'handler_factory_generic';
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}
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/**
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* Load function for slot info objects.
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*
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* @param $slot_id
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* The internal slot ID.
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* @param $refresh
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* If this is set to TRUE, the internal slot cache will be flushed.
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* @return
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* The slot object or NULL if it is not defined.
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*/
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function handler_slot_load($slot_id, $refresh = FALSE) {
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static $slots;
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if ($refresh) {
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$slots = array();
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}
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if (empty($slots[$slot_id])) {
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$slot = db_fetch_object(db_query("SELECT slot, title, interface, factory, default_handler, targets, description FROM {handler_slot_info} WHERE slot='%s'", array($slot_id)));
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$slot->targets = unserialize($slot->targets);
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$slots[$slot_id] = $slot;
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}
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return $slots[$slot_id];
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}
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/**
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* Load function for handler info objects.
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*
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* @param $handler_id
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* The internal handler ID.
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* @param $refresh
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* If this is set to TRUE, the internal handler cache will be flushed.
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* @return
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* The handler object or NULL if not defined.
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*/
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function handler_load($handler_id, $refresh = FALSE) {
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static $handlers;
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if ($refresh) {
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$handlers = array();
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}
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if (empty($handlers[$handler_id])) {
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$handler = db_fetch_object(db_query("SELECT handler, slot, title, class, description FROM {handler_info} WHERE handler='%s'", array($handler_id)));
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$handlers[$handler_id] = $handler;
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}
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return $handlers[$handler_id];
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}
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/**
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* The generic handler factory.
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*
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* In most cases, this factory will be sufficient for handlers that do not
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* need a new object generated on each call.
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*
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* @param $options
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* The options array determines which handler object should be used, depending
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* on the current configuration.
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* @param $slot_id
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* The slot we are handling.
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* @return
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* The handler object required.
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*/
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function handler_factory_generic(Array $options = array(), $slot_id) {
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static $handlers;
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static $env;
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// We only need one environment variable in the default case.
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if (empty($env)) {
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$env = new EnvironmentDefault();
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}
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$class = handler_get_registered_handler($slot_id, $options);
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// If we haven't already created this handler, instantiate a new object for it.
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if (empty($handlers[$class])) {
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$handler = new $class();
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$handler->setEnvironment($env);
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$handlers[$class] = $handler;
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}
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return $handlers[$class];
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}
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/**
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* Derive the handler class for the specified target.
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*
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* @param $target_id
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* The internal ID of the target.
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* @param $targets
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* The array of targets to help route this handler request. If it does not
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* have a value specified for every target, it will be filled in with the
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* slot-defined defaults.
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* @return
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* The name of the class that should be loaded for this
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* target/option configuration.
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*/
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function handler_get_registered_handler($slot_id, $targets) {
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$mapping = handler_slot_mapping($slot_id);
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$targets += handler_default_targets($slot_id);
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// Because we need to traverse down the options array somehow, we normalize
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// the array order to alphabetic by the option key. That allows us to walk
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// the array in a standardized order.
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ksort($options);
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$handler_id = &$mapping;
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foreach ($options as $option => $value) {
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if (isset($handler_id[$value])) {
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$handler_id = &$handler_id[$value];
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}
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else {
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$slot = handler_target_load($slot_id);
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$handler_id = $slot->default_handler;
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break;
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}
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}
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$handler = handler_load($handler_id);
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return $handler->class;
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}
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function handler_slot_mapping($slot_id) {
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$mapping = db_result(db_query("SELECT mapping FROM {handler_mapping} WHERE target='%s'", array($target_id)));
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if ($mapping) {
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$mapping = unserialize($mapping);
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}
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else {
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$mapping = array();
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}
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return $mapping;
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}
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/**
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* Asociate a given handler to a give slot for the specified targets.
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*
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* @param $slot_id
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* The internal ID of the slot.
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* @param $handler_id
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* The internal ID of the hand
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* @param $options
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* The array of options
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*/
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function handler_attach($slot_id, $handler_id, $targets) {
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db_query("INSERT INTO {handler_attachments} (slot_id, handler_id, targets) VALUES ('%s', '%s', '%s')", array(
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$slot_id, $handler_id, serialize($targets)
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));
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/*
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$mapping = db_result(db_query("SELECT mapping FROM {handler_mapping} WHERE slot='%s'", array($slot_id)));
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| 406 |
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$is_new = FALSE;
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| 408 |
if ($mapping) {
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$mapping = unserialize($mapping);
|
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}
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else {
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$mapping = array();
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$is_new = TRUE;
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}
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$options += handler_default_options($slot_id);
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ksort($options);
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$map_point = &$mapping;
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foreach ($options as $key => $value) {
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| 421 |
if (empty($map_point[$value])) {
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| 422 |
$map_point[$value] = array();
|
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}
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| 424 |
$map_point = &$map_point[$value];
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}
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$map_point = $handler_id;
|
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// It would be nicer do a delete/insert cycle, but that would result in a race
|
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// condition. What we really want here is a merge query, but those will have
|
| 431 |
// to wait until Drupal 7.
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| 432 |
if ($is_new) {
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db_query("INSERT INTO {handler_mapping} (slot, mapping) VALUES ('%s', '%s')", array($slot_id, serialize($mapping)));
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| 434 |
}
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| 435 |
else {
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| 436 |
db_query("UPDATE {handler_mapping} SET mapping='%s' WHERE slot='%s'", array(serialize($mapping), $slot_id));
|
| 437 |
}
|
| 438 |
*/
|
| 439 |
}
|
| 440 |
|
| 441 |
/**
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| 442 |
* Get the default targets for a given slot.
|
| 443 |
*
|
| 444 |
* @param $slot_id
|
| 445 |
* The internal ID of the slot.
|
| 446 |
* @return
|
| 447 |
* An associative array of the default targets for the specified slot.
|
| 448 |
*/
|
| 449 |
function handler_default_targets($slot_id) {
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| 450 |
$slot = handler_slot_load($slot_id);
|
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return $slot->targets;
|
| 453 |
}
|
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|
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