Index: modules/nodereference/nodereference.module
===================================================================
RCS file: /cvs/drupal-contrib/contributions/modules/cck/modules/nodereference/Attic/nodereference.module,v
retrieving revision 1.138.2.59
diff -u -p -r1.138.2.59 nodereference.module
--- modules/nodereference/nodereference.module	19 Jul 2009 13:03:56 -0000	1.138.2.59
+++ modules/nodereference/nodereference.module	19 Aug 2009 00:33:45 -0000
@@ -52,6 +52,16 @@ function nodereference_theme() {
 }
 
 /**
+ * Implementation of hook_views_api().
+ */
+function nodereference_views_api() {
+  return array(
+    'api' => 2,
+    'path' => drupal_get_path('module', 'nodereference') . '/views',
+  );
+}
+
+/**
  * Implementaion of hook_ctools_plugin_directory().
  */
 function nodereference_ctools_plugin_directory($module, $plugin) {
@@ -173,6 +183,31 @@ function nodereference_field_settings($o
         'label' => t($field['widget']['label']),
         'content_field_name' => $field['field_name'],
       );
+
+      // Add a reverse relationship to get information about referring items.
+      $field_types = _content_field_types();
+      $types = array();
+      foreach (content_types() as $type) {
+        if (isset($type['fields'][$field['field_name']])) {
+          $types[] = $type['name'];
+        }
+      }
+      $label_truncated = truncate_utf8(t($field['widget']['label']), 10, TRUE);
+      $data[$table_alias]['vid'] = array(
+        'group' => t('Content'),
+        'title' => t('@label (!name) - reverse reference', array('@label' => t($field['widget']['label']), '!name' => $field['field_name'])),
+        'title short' => t('@label-truncated reverse reference', array('@label-truncated' => $label_truncated)),
+        'help' => t($field_types[$field['type']]['label']) .' ('. t('reverse reference') .') - '. t('Appears in: @types', array('@types' => implode(', ', $types))),
+        'relationship' => array(
+          'base' => 'node',
+          'base field' => 'vid',
+          'left_field' => 'nid',
+          'field' => $db_info['columns']['nid']['column'],
+          'handler' => 'nodereference_handler_relationship_reverse',
+          'label' => t('@label reverse reference', array('@label' => t($field['widget']['label']))),
+          'content_field_name' => $field['field_name'],
+        ),
+      );
       return $data;
   }
 }
Index: modules/nodereference/views/nodereference.views.inc
===================================================================
RCS file: modules/nodereference/views/nodereference.views.inc
diff -N modules/nodereference/views/nodereference.views.inc
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ modules/nodereference/views/nodereference.views.inc	17 Aug 2009 02:10:01 -0000
@@ -0,0 +1,23 @@
+<?php
+// $Id$
+
+/**
+ * @file
+ * Views integration interface for nodereference module.
+ */
+
+/**
+ * Implementation of hook_views_handlers().
+ */
+function nodereference_views_handlers() {
+  return array(
+    'info' => array(
+      'path' => drupal_get_path('module', 'nodereference') . '/views/handlers',
+    ),
+    'handlers' => array(
+      'nodereference_handler_relationship_reverse' => array(
+        'parent' => 'views_handler_relationship',
+      ),
+    ),
+  );
+}
Index: modules/nodereference/views/handlers/nodereference_handler_relationship_reverse.inc
===================================================================
RCS file: modules/nodereference/views/handlers/nodereference_handler_relationship_reverse.inc
diff -N modules/nodereference/views/handlers/nodereference_handler_relationship_reverse.inc
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ modules/nodereference/views/handlers/nodereference_handler_relationship_reverse.inc	19 Aug 2009 00:26:20 -0000
@@ -0,0 +1,187 @@
+<?php
+// $Id$
+
+/**
+ * @file
+ * Handles reverse node references using a nested join and deals properly with
+ * multiple values by allowing the views administrator to select deltas.
+ *
+ * Tipical relationships for node reference fields generate two joins that
+ * look like this:
+ *
+ * @code
+ *   FROM {node} node
+ *     LEFT JOIN {content_field_table} node_data_field_table ON node.vid = node_data_field_table.vid
+ *     {join-type} JOIN {node} node_node_data_field_table ON node_data_field_table.field_nid = node_node_data_field_table.nid
+ * @code
+ *
+ * However, this kind of joins handle relationships between referrer nodes
+ * and their parents. A referrer node can display information about the
+ * referred node, but not the other way around. We cannot display fields
+ * of the referring node from a parent node because the link goes from child
+ * to parent.
+ * To provide a relationships from parent to child, we need to generate a join
+ * from the nid of the parent node to the reference field on the referrer node,
+ * and because this is using the nid, we should do it in a way that does not
+ * generate duplicate records when the referrer nodes have support for node
+ * revisions enabled.
+ *
+ * This can be done using a nested join like the following:
+ *
+ * @code
+ *   FROM {node} node
+ *     {join-type} JOIN (
+ *       {content_field_table} node_data_field_table
+ *       INNER JOIN {node} node_node_data_field_table ON node_data_field_table.vid = node_node_data_field_table.vid
+ *     ) ON node.nid = node_data_field_table.field_nid
+ * @code
+ *
+ * Note that {join-type} depends on whether the relationship is
+ * required (INNER) or not (LEFT).
+ */
+class nodereference_handler_relationship_reverse extends views_handler_relationship {
+  var $content_field;
+
+  function construct() {
+    parent::construct();
+
+    $this->content_field = content_fields($this->definition['content_field_name']);
+  }
+
+  function option_definition() {
+    $options = parent::option_definition();
+    $options['delta'] = array('default' => -1);
+
+    return $options;
+  }
+
+  /**
+   * Add a delta selector for multiple fields.
+   */
+  function options_form(&$form, &$form_state) {
+    $field = $this->content_field;
+    parent::options_form($form, $form_state);
+
+    // Only add the form gadget if the field is multiple.
+    if ($field['multiple']) {
+      $max_delta = $field['multiple'];
+      // 1 means unlimited.
+      if ($max_delta == 1) {
+        $max_delta = 10;
+      }
+
+      $options = array('-1' => t('All'));
+      for ($i = 0; $i < $max_delta; $i++) {
+        $options[$i] = $i + 1;
+      }
+      $form['delta'] = array(
+        '#type' => 'select',
+        '#options' => $options,
+        '#default_value' => $this->options['delta'],
+        '#title' => t('Delta'),
+        '#description' => t('The delta allows you to select which item in a multiple value field to key the relationship off of. Select "1" to use the first item, "2" for the second item, and so on. If you select "All", each item in the field will create a new row, which may appear to cause duplicates.'),
+      );
+    }
+  }
+
+  function ensure_my_table() {
+    if (!isset($this->table_alias)) {
+      if (!method_exists($this->query, 'ensure_table')) { vpr_trace(); exit; }
+
+      // Since nested joins are not directly supported by Views, we are going
+      // to do here part of the job performed by views_query::ensure_table().
+
+      if (empty($this->relationship)) {
+        $this->relationship = $this->query->base_table;
+      }
+
+      if ($this->relationship == $this->query->base_table && !empty($this->query->tables[$this->relationship][$this->table])) {
+        $this->table_alias = $this->query->tables[$relationship][$this->table]['alias'];
+      }
+      elseif (!array_key_exists($this->relationship, $this->query->relationships)) {
+        $this->table_alias = FALSE;
+      }
+      elseif ($this->table == $this->query->relationships[$this->relationship]['base']) {
+        $this->table_alias = $this->relationship;
+      }
+      else {
+        // Build the main join based on the views data cache.
+        $main_join = $this->query->get_join_data($this->table, $this->query->relationships[$this->relationship]['base']);
+
+        // We want to alter the join so that it uses the field column instead
+        // of the vid.
+        $main_join_definition = $main_join->definition;
+        $main_join_definition['left_table'] = $this->relationship;
+        $main_join_definition['left_field'] = $this->definition['left_field'];
+        $main_join_definition['field'] = $this->definition['field'];
+        if (!empty($this->options['required'])) {
+          $main_join_definition['type'] = 'INNER';
+        }
+
+        $delta = isset($this->options['delta']) ? $this->options['delta'] : -1;
+        if ($delta != -1) {
+          if (!isset($main_join_definition['extra'])) {
+            $main_join_definition['extra'] = array();
+          }
+          $main_join_definition['extra'][] = array(
+            'field' => 'delta',
+            'value' => $delta,
+            'numeric' => TRUE,
+          );
+        }
+
+        // Build a new join object with our new definition.
+        $main_join = new nodereference_nested_join();
+        $main_join->definition = $main_join_definition;
+        $main_join->construct();
+        $main_join->adjusted = TRUE;
+        $this->table_alias = $this->query->ensure_table($this->table, $this->relationship, $main_join);
+
+        // Let's build the nested join.
+        $nested_join_definition = $this->definition;
+        $nested_join_definition['table'] = $this->definition['base'];
+        $nested_join_definition['left_field'] = $nested_join_definition['field'] = $nested_join_definition['base field'];
+        $nested_join_definition['left_table'] = $this->table_alias;
+        $nested_join_definition['type'] = 'INNER';
+
+        $nested_join = new nodereference_nested_join();
+        $nested_join->definition = $nested_join_definition;
+        $nested_join->construct();
+        $nested_join->adjusted = TRUE;
+        $nested_alias = $nested_join_definition['table'] .'_'. $this->table;
+
+        $this->alias = $this->query->add_relationship($nested_alias, $nested_join, $this->definition['base'], $this->relationship);
+
+        $main_join->_set_nested_join($nested_join, $this->alias);
+      }
+    }
+    return $this->table_alias;
+  }
+
+  function query() {
+    $this->ensure_my_table();
+  }
+}
+
+class nodereference_nested_join extends views_join {
+  var $nested_join;
+  var $nested_alias;
+
+  function _set_nested_join($nested_join, $nested_alias) {
+    $this->nested_join = $nested_join;
+    $this->nested_alias = $nested_alias;
+  }
+
+  function join($table, &$query, $build_main_join = FALSE) {
+    if (!isset($this->nested_join)) {
+      if ($build_main_join) {
+        return parent::join($table, $query);
+      }
+      return '';
+    }
+    $output = parent::join($table, $query);
+    $nested_join = $this->nested_join->join($query->table_queue[$this->nested_alias], $query, TRUE);
+    $output = preg_replace('`JOIN ({[_a-z0-9]+} [_a-z0-9]+) ON`', "JOIN (\n\\1\n{$nested_join}\n) ON", $output);
+    return $output;
+  }
+}