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-rw-r--r--engine/classes/ElggPriorityList.php96
1 files changed, 87 insertions, 9 deletions
diff --git a/engine/classes/ElggPriorityList.php b/engine/classes/ElggPriorityList.php
index 39fe698da..931138106 100644
--- a/engine/classes/ElggPriorityList.php
+++ b/engine/classes/ElggPriorityList.php
@@ -26,6 +26,7 @@
*
*
* // Array
+ *
* $pl = new ElggPriorityList();
* $pl[] = 'Element 0';
* $pl[-5] = 'Element -5';
@@ -45,24 +46,45 @@
* 10 => Element 10
*
*
- * Collisions with priority are handled by inserting the element as close to the requested priority
- * as possible.
+ * Collisions with priority are handled by default differently in the OOP and the array interfaces.
+ *
+ * If using the OOP interface, the default is to insert the element as close to the requested
+ * priority as possible.
*
* $pl = new ElggPriorityList();
- * $pl[5] = 'Element 5';
- * $pl[5] = 'Colliding element 5';
- * $pl[5] = 'Another colliding element 5';
+ * $pl->add('Element 5', 5);
+ * $pl->add('Colliding element 5', 5);
+ * $pl->add('Another colliding element 5', 5);
*
* var_dump($pl->getElements());
*
* Yields:
- *
* array(
* 5 => 'Element 5',
* 6 => 'Colliding element 5',
* 7 => 'Another colliding element 5'
* )
*
+ * If using the array interface, elements are added at exactly the priority, displacing other
+ * elements if necessary. This behavior is also available by passing true as the 3rd argument to
+ * ->add():
+ *
+ * $pl = new ElggPriorityList();
+ * $pl[5] = 'Element 5';
+ * $pl[6] = 'Element 6';
+ * $pl[5] = 'Colliding element 5'; // shifts the previous two up by one
+ * $pl->add('Another colliding element 5', 5, true); // shifts the previous three up by one
+ *
+ * var_dump($pl->getElements());
+ *
+ * Yields:
+ * array(
+ * 5 => 'Another colliding element 5',
+ * 6 => 'Colliding element 5',
+ * 7 => 'Element 5',
+ * 8 => 'Element 6'
+ * )
+ *
* @package Elgg.Core
* @subpackage Helpers
*/
@@ -101,16 +123,21 @@ class ElggPriorityList
* maintains its priority and the new element is to the next available
* slot, taking into consideration all previously registered elements.
* Negative elements are accepted.
- * @return int The priority the element was added at.
+ * @param bool $exact If true, will put the element at exactly the priority specified, displacing
+ * other elements.
+ * @return int The priority of the added element.
*/
- public function add($element, $priority = null) {
+ public function add($element, $priority = null, $exact = false) {
if ($priority !== null && !is_numeric($priority)) {
return false;
+ } elseif ($exact) {
+ $this->shiftElementsSegment($priority);
} else {
$priority = $this->getNextPriority($priority);
}
$this->elements[$priority] = $element;
+ $this->sorted = false;
return $priority;
}
@@ -134,6 +161,32 @@ class ElggPriorityList
}
/**
+ * Move an existing element to a new priority.
+ *
+ * @param int $current_priority
+ * @param int $new_priority
+ * @param bool $exact
+ * @return bool
+ */
+ public function move($current_priority, $new_priority, $exact = false) {
+ $current_priority = (int) $current_priority;
+ $new_priority = (int) $new_priority;
+
+ if (!isset($this->elements[$current_priority])) {
+ return false;
+ }
+
+ if ($current_priority == $new_priority) {
+ return true;
+ }
+
+ $element = $this->elements[$current_priority];
+ unset($this->elements[$current_priority]);
+
+ return $this->add($element, $new_priority, $exact);
+ }
+
+ /**
* Returns the elements
*
* @param type $elements
@@ -186,6 +239,29 @@ class ElggPriorityList
}
/**
+ * Shift a segment of elements starting at $index up by one until the end of the array or
+ * there's a gap in the indexes. This produces a space at $index to insert a new element.
+ *
+ * @param type $index The index to start
+ * @return array
+ */
+ private function shiftElementsSegment($index) {
+ $index = (int) $index;
+ // @todo probably a better way.
+ $replace_elements = array();
+ while (isset($this->elements[$index])) {
+ $replace_elements[$index + 1] = $this->elements[$index];
+ unset($this->elements[$index]);
+ $index++;
+ }
+
+ // insert old ones
+ foreach ($replace_elements as $index => $element) {
+ $this->elements[$index] = $element;
+ }
+ }
+
+ /**
* Returns the next priority available.
*
* @param int $near Make the priority as close to $near as possible.
@@ -295,7 +371,9 @@ class ElggPriorityList
}
public function offsetSet($offset, $value) {
- return $this->add($value, $offset);
+ // for $pl[] = 'New element'
+ $exact = ($offset !== null);
+ return $this->add($value, $offset, $exact);
}
public function offsetUnset($offset) {