first import

sites/all/modules/migrate/includes/group.inc

@@ -0,0 +1,109 @@
+<?php
+
+/**
+ * @file
+ * Definition for a migration group.
+ */
+
+class MigrateGroup {
+  /**
+   * The name of the group - used to identify it in drush commands.
+   *
+   * @var string
+   */
+  protected $name;
+  public function getName() {
+    return $this->name;
+  }
+
+  /**
+   * List of groups this group is dependent on.
+   *
+   * @var array
+   */
+  protected $dependencies = array();
+  public function getDependencies() {
+    return $this->dependencies;
+  }
+
+  /**
+   * The central list of all known groups, keyed by group name.
+   *
+   * @var array
+   */
+  static protected $groupList = array();
+  static public function groups() {
+    $groups = array();
+    $dependent_groups = array();
+    $required_groups = array();
+    foreach (self::$groupList as $name => $group) {
+      $dependencies = $group->getDependencies();
+      if (count($dependencies) > 0) {
+        // Set groups with dependencies aside for reordering
+        $dependent_groups[$name] = $group;
+        $required_groups += $dependencies;
+      }
+      else {
+        // No dependencies, just add
+        $groups[$name] = $group;
+      }
+    }
+    $iterations = 0;
+    while (count($dependent_groups) > 0) {
+      if ($iterations++ > 20) {
+        $group_names = implode(',', array_keys($dependent_groups));
+        throw new MigrateException(t('Failure to sort migration list - most likely due ' .
+              'to circular dependencies involving groups !group_names',
+        array('!group_names' => $group_names)));
+      }
+      foreach ($dependent_groups as $name => $group) {
+        $ready = TRUE;
+        // Scan all the dependencies for this group and make sure they're all
+        // in the final list
+        foreach ($group->getDependencies() as $dependency) {
+          if (!isset($groups[$dependency])) {
+            $ready = FALSE;
+            break;
+          }
+        }
+        if ($ready) {
+          // Yes they are! Move this group to the final list
+          $groups[$name] = $group;
+          unset($dependent_groups[$name]);
+        }
+      }
+    }
+
+    return $groups;
+  }
+
+  /**
+   * Basic constructor.
+   *
+   * @param string $name
+   *  Group name.
+   *
+   * @param array $dependencies
+   *  List of dependent groups.
+   */
+  public function __construct($name, $dependencies = array()) {
+    $this->name = $name;
+    $this->dependencies = $dependencies;
+  }
+
+  /**
+   * Retrieve (creating if necessary) an instance of the named group.
+   *
+   * @param string $name
+   *  Group name.
+   *
+   * @param array $dependencies
+   *  List of dependent groups.
+   */
+  static public function getInstance($name, $dependencies = array()) {
+    if (empty(self::$groupList[$name])) {
+      self::$groupList[$name] = new MigrateGroup($name, $dependencies);
+    }
+    return self::$groupList[$name];
+  }
+}