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phab/src/infrastructure/query/order/PhabricatorQueryOrderVector.php
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PhabricatorQueryOrderVector.php
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<?php
/**
* Structural class representing a column ordering for a query.
*
* Queries often order results on multiple columns. For example, projects might
* be ordered by "name, id". This class wraps a list of column orderings and
* makes them easier to manage.
*
* To construct an order vector, use @{method:newFromVector}:
*
* $vector = PhabricatorQueryOrderVector::newFromVector(array('name', 'id'));
*
* You can iterate over an order vector normally:
*
* foreach ($vector as $item) {
* // ...
* }
*
* The items are objects of class @{class:PhabricatorQueryOrderItem}.
*
* This class is primarily internal to the query infrastructure, and most
* application code should not need to interact with it directly.
*/
final class PhabricatorQueryOrderVector
extends Phobject
implements Iterator {
private $items;
private $keys;
private $cursor;
private function __construct() {
// <private>
}
public static function newFromVector($vector) {
if ($vector instanceof PhabricatorQueryOrderVector) {
return (clone $vector);
}
if (!is_array($vector)) {
throw new Exception(
pht(
'An order vector can only be constructed from a list of strings or '.
'another order vector.'));
}
if (!$vector) {
throw new Exception(
pht(
'An order vector must not be empty.'));
}
$items = array();
foreach ($vector as $key => $scalar) {
if (!is_string($scalar)) {
throw new Exception(
pht(
'Value with key "%s" in order vector is not a string (it has '.
'type "%s"). An order vector must contain only strings.',
$key,
gettype($scalar)));
}
$item = PhabricatorQueryOrderItem::newFromScalar($scalar);
// Orderings like "id, id, id" or "id, -id" are meaningless and invalid.
if (isset($items[$item->getOrderKey()])) {
throw new Exception(
pht(
'Order vector "%s" specifies order "%s" twice. Each component '.
'of an ordering must be unique.',
implode(', ', $vector),
$item->getOrderKey()));
}
$items[$item->getOrderKey()] = $item;
}
$obj = new PhabricatorQueryOrderVector();
$obj->items = $items;
$obj->keys = array_keys($items);
return $obj;
}
public function appendVector($vector) {
$vector = self::newFromVector($vector);
// When combining vectors (like "group by" and "order by" vectors), there
// may be redundant columns. We only want to append unique columns which
// aren't already present in the vector.
foreach ($vector->items as $key => $item) {
if (empty($this->items[$key])) {
$this->items[$key] = $item;
$this->keys[] = $key;
}
}
return $this;
}
public function getAsString() {
$scalars = array();
foreach ($this->items as $item) {
$scalars[] = $item->getAsScalar();
}
return implode(', ', $scalars);
}
public function containsKey($key) {
return isset($this->items[$key]);
}
/* -( Iterator Interface )------------------------------------------------- */
public function rewind() {
$this->cursor = 0;
}
public function current() {
return $this->items[$this->key()];
}
public function key() {
return $this->keys[$this->cursor];
}
public function next() {
++$this->cursor;
}
public function valid() {
return isset($this->keys[$this->cursor]);
}
}
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