| 1 | <?php |
| 2 | /* |
| 3 | +--------------------------------------------------------------------+ |
| 4 | | Copyright CiviCRM LLC. All rights reserved. | |
| 5 | | | |
| 6 | | This work is published under the GNU AGPLv3 license with some | |
| 7 | | permitted exceptions and without any warranty. For full license | |
| 8 | | and copyright information, see https://civicrm.org/licensing | |
| 9 | +--------------------------------------------------------------------+ |
| 10 | */ |
| 11 | |
| 12 | /** |
| 13 | * A lazy-array works much like a regular array or ArrayObject. However, it is |
| 14 | * initially empty - and it is only populated if used. |
| 15 | */ |
| 16 | class CRM_Utils_LazyArray implements ArrayAccess, IteratorAggregate, Countable { |
| 17 | |
| 18 | /** |
| 19 | * A function which generates a list of values. |
| 20 | * |
| 21 | * @var callable |
| 22 | * function(): iterable |
| 23 | */ |
| 24 | private $func; |
| 25 | |
| 26 | /** |
| 27 | * Cached values |
| 28 | * |
| 29 | * @var array|null |
| 30 | */ |
| 31 | private $cache; |
| 32 | |
| 33 | /** |
| 34 | * CRM_Utils_LazyList constructor. |
| 35 | * |
| 36 | * @param callable $func |
| 37 | * Function which provides a list of values (array/iterator/generator). |
| 38 | */ |
| 39 | public function __construct($func) { |
| 40 | $this->func = $func; |
| 41 | } |
| 42 | |
| 43 | /** |
| 44 | * Determine if the content has been fetched. |
| 45 | * |
| 46 | * @return bool |
| 47 | */ |
| 48 | public function isLoaded() { |
| 49 | return $this->cache !== NULL; |
| 50 | } |
| 51 | |
| 52 | public function load($force = FALSE) { |
| 53 | if ($this->cache === NULL || $force) { |
| 54 | $this->cache = CRM_Utils_Array::cast(call_user_func($this->func)); |
| 55 | } |
| 56 | return $this; |
| 57 | } |
| 58 | |
| 59 | public function offsetExists($offset) { |
| 60 | return isset($this->load()->cache[$offset]); |
| 61 | } |
| 62 | |
| 63 | public function &offsetGet($offset) { |
| 64 | return $this->load()->cache[$offset]; |
| 65 | } |
| 66 | |
| 67 | public function offsetSet($offset, $value) { |
| 68 | if ($offset === NULL) { |
| 69 | $this->load()->cache[] = $value; |
| 70 | } |
| 71 | else { |
| 72 | $this->load()->cache[$offset] = $value; |
| 73 | } |
| 74 | } |
| 75 | |
| 76 | public function offsetUnset($offset) { |
| 77 | unset($this->load()->cache[$offset]); |
| 78 | } |
| 79 | |
| 80 | public function getIterator() { |
| 81 | return new ArrayIterator($this->load()->cache); |
| 82 | } |
| 83 | |
| 84 | /** |
| 85 | * @return array |
| 86 | */ |
| 87 | public function getArrayCopy() { |
| 88 | return $this->load()->cache; |
| 89 | } |
| 90 | |
| 91 | public function count() { |
| 92 | return count($this->load()->cache); |
| 93 | } |
| 94 | |
| 95 | } |