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Drupal 8.0.0 beta 12. More info: https://www.drupal.org/node/2514176

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Pantheon Automation 2015-08-17 17:00:26 -07:00 • committed by Greg Anderson
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core/lib/Drupal/Component/Utility
NestedArray.php

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core/lib/Drupal/Component/Utility/NestedArray.php Normal file
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<?php
/**
* @file
* Contains \Drupal\Component\Utility\NestedArray.
*/
namespace Drupal\Component\Utility;
/**
* Provides helpers to perform operations on nested arrays and array keys of variable depth.
*
* @ingroup utility
*/
class NestedArray {
/**
* Retrieves a value from a nested array with variable depth.
*
* This helper function should be used when the depth of the array element
* being retrieved may vary (that is, the number of parent keys is variable).
* It is primarily used for form structures and renderable arrays.
*
* Without this helper function the only way to get a nested array value with
* variable depth in one line would be using eval(), which should be avoided:
* @code
* // Do not do this! Avoid eval().
* // May also throw a PHP notice, if the variable array keys do not exist.
* eval('$value = $array[\'' . implode("']['", $parents) . "'];");
* @endcode
*
* Instead, use this helper function:
* @code
* $value = NestedArray::getValue($form, $parents);
* @endcode
*
* A return value of NULL is ambiguous, and can mean either that the requested
* key does not exist, or that the actual value is NULL. If it is required to
* know whether the nested array key actually exists, pass a third argument
* that is altered by reference:
* @code
* $key_exists = NULL;
* $value = NestedArray::getValue($form, $parents, $key_exists);
* if ($key_exists) {
* // Do something with $value.
* }
* @endcode
*
* However if the number of array parent keys is static, the value should
* always be retrieved directly rather than calling this function.
* For instance:
* @code
* $value = $form['signature_settings']['signature'];
* @endcode
*
* @param array $array
* The array from which to get the value.
* @param array $parents
* An array of parent keys of the value, starting with the outermost key.
* @param bool $key_exists
* (optional) If given, an already defined variable that is altered by
* reference.
*
* @return mixed
* The requested nested value. Possibly NULL if the value is NULL or not all
* nested parent keys exist. $key_exists is altered by reference and is a
* Boolean that indicates whether all nested parent keys exist (TRUE) or not
* (FALSE). This allows to distinguish between the two possibilities when
* NULL is returned.
*
* @see NestedArray::setValue()
* @see NestedArray::unsetValue()
*/
public static function &getValue(array &$array, array $parents, &$key_exists = NULL) {
$ref = &$array;
foreach ($parents as $parent) {
if (is_array($ref) && array_key_exists($parent, $ref)) {
$ref = &$ref[$parent];
}
else {
$key_exists = FALSE;
$null = NULL;
return $null;
}
}
$key_exists = TRUE;
return $ref;
}
/**
* Sets a value in a nested array with variable depth.
*
* This helper function should be used when the depth of the array element you
* are changing may vary (that is, the number of parent keys is variable). It
* is primarily used for form structures and renderable arrays.
*
* Example:
* @code
* // Assume you have a 'signature' element somewhere in a form. It might be:
* $form['signature_settings']['signature'] = array(
* '#type' => 'text_format',
* '#title' => t('Signature'),
* );
* // Or, it might be further nested:
* $form['signature_settings']['user']['signature'] = array(
* '#type' => 'text_format',
* '#title' => t('Signature'),
* );
* @endcode
*
* To deal with the situation, the code needs to figure out the route to the
* element, given an array of parents that is either
* @code array('signature_settings', 'signature') @endcode
* in the first case or
* @code array('signature_settings', 'user', 'signature') @endcode
* in the second case.
*
* Without this helper function the only way to set the signature element in
* one line would be using eval(), which should be avoided:
* @code
* // Do not do this! Avoid eval().
* eval('$form[\'' . implode("']['", $parents) . '\'] = $element;');
* @endcode
*
* Instead, use this helper function:
* @code
* NestedArray::setValue($form, $parents, $element);
* @endcode
*
* However if the number of array parent keys is static, the value should
* always be set directly rather than calling this function. For instance,
* for the first example we could just do:
* @code
* $form['signature_settings']['signature'] = $element;
* @endcode
*
* @param array $array
* A reference to the array to modify.
* @param array $parents
* An array of parent keys, starting with the outermost key.
* @param mixed $value
* The value to set.
* @param bool $force
* (optional) If TRUE, the value is forced into the structure even if it
* requires the deletion of an already existing non-array parent value. If
* FALSE, PHP throws an error if trying to add into a value that is not an
* array. Defaults to FALSE.
*
* @see NestedArray::unsetValue()
* @see NestedArray::getValue()
*/
public static function setValue(array &$array, array $parents, $value, $force = FALSE) {
$ref = &$array;
foreach ($parents as $parent) {
// PHP auto-creates container arrays and NULL entries without error if $ref
// is NULL, but throws an error if $ref is set, but not an array.
if ($force && isset($ref) && !is_array($ref)) {
$ref = array();
}
$ref = &$ref[$parent];
}
$ref = $value;
}
/**
* Unsets a value in a nested array with variable depth.
*
* This helper function should be used when the depth of the array element you
* are changing may vary (that is, the number of parent keys is variable). It
* is primarily used for form structures and renderable arrays.
*
* Example:
* @code
* // Assume you have a 'signature' element somewhere in a form. It might be:
* $form['signature_settings']['signature'] = array(
* '#type' => 'text_format',
* '#title' => t('Signature'),
* );
* // Or, it might be further nested:
* $form['signature_settings']['user']['signature'] = array(
* '#type' => 'text_format',
* '#title' => t('Signature'),
* );
* @endcode
*
* To deal with the situation, the code needs to figure out the route to the
* element, given an array of parents that is either
* @code array('signature_settings', 'signature') @endcode
* in the first case or
* @code array('signature_settings', 'user', 'signature') @endcode
* in the second case.
*
* Without this helper function the only way to unset the signature element in
* one line would be using eval(), which should be avoided:
* @code
* // Do not do this! Avoid eval().
* eval('unset($form[\'' . implode("']['", $parents) . '\']);');
* @endcode
*
* Instead, use this helper function:
* @code
* NestedArray::unset_nested_value($form, $parents, $element);
* @endcode
*
* However if the number of array parent keys is static, the value should
* always be set directly rather than calling this function. For instance, for
* the first example we could just do:
* @code
* unset($form['signature_settings']['signature']);
* @endcode
*
* @param array $array
* A reference to the array to modify.
* @param array $parents
* An array of parent keys, starting with the outermost key and including
* the key to be unset.
* @param bool $key_existed
* (optional) If given, an already defined variable that is altered by
* reference.
*
* @see NestedArray::setValue()
* @see NestedArray::getValue()
*/
public static function unsetValue(array &$array, array $parents, &$key_existed = NULL) {
$unset_key = array_pop($parents);
$ref = &self::getValue($array, $parents, $key_existed);
if ($key_existed && is_array($ref) && array_key_exists($unset_key, $ref)) {
$key_existed = TRUE;
unset($ref[$unset_key]);
}
else {
$key_existed = FALSE;
}
}
/**
* Determines whether a nested array contains the requested keys.
*
* This helper function should be used when the depth of the array element to
* be checked may vary (that is, the number of parent keys is variable). See
* NestedArray::setValue() for details. It is primarily used for form
* structures and renderable arrays.
*
* If it is required to also get the value of the checked nested key, use
* NestedArray::getValue() instead.
*
* If the number of array parent keys is static, this helper function is
* unnecessary and the following code can be used instead:
* @code
* $value_exists = isset($form['signature_settings']['signature']);
* $key_exists = array_key_exists('signature', $form['signature_settings']);
* @endcode
*
* @param array $array
* The array with the value to check for.
* @param array $parents
* An array of parent keys of the value, starting with the outermost key.
*
* @return bool
* TRUE if all the parent keys exist, FALSE otherwise.
*
* @see NestedArray::getValue()
*/
public static function keyExists(array $array, array $parents) {
// Although this function is similar to PHP's array_key_exists(), its
// arguments should be consistent with getValue().
$key_exists = NULL;
self::getValue($array, $parents, $key_exists);
return $key_exists;
}
/**
* Merges multiple arrays, recursively, and returns the merged array.
*
* This function is similar to PHP's array_merge_recursive() function, but it
* handles non-array values differently. When merging values that are not both
* arrays, the latter value replaces the former rather than merging with it.
*
* Example:
* @code
* $link_options_1 = array('fragment' => 'x', 'attributes' => array('title' => t('X'), 'class' => array('a', 'b')));
* $link_options_2 = array('fragment' => 'y', 'attributes' => array('title' => t('Y'), 'class' => array('c', 'd')));
*
* // This results in array('fragment' => array('x', 'y'), 'attributes' => array('title' => array(t('X'), t('Y')), 'class' => array('a', 'b', 'c', 'd'))).
* $incorrect = array_merge_recursive($link_options_1, $link_options_2);
*
* // This results in array('fragment' => 'y', 'attributes' => array('title' => t('Y'), 'class' => array('a', 'b', 'c', 'd'))).
* $correct = NestedArray::mergeDeep($link_options_1, $link_options_2);
* @endcode
*
* @param array ...
* Arrays to merge.
*
* @return array
* The merged array.
*
* @see NestedArray::mergeDeepArray()
*/
public static function mergeDeep() {
return self::mergeDeepArray(func_get_args());
}
/**
* Merges multiple arrays, recursively, and returns the merged array.
*
* This function is equivalent to NestedArray::mergeDeep(), except the
* input arrays are passed as a single array parameter rather than a variable
* parameter list.
*
* The following are equivalent:
* - NestedArray::mergeDeep($a, $b);
* - NestedArray::mergeDeepArray(array($a, $b));
*
* The following are also equivalent:
* - call_user_func_array('NestedArray::mergeDeep', $arrays_to_merge);
* - NestedArray::mergeDeepArray($arrays_to_merge);
*
* @param array $arrays
* An arrays of arrays to merge.
* @param bool $preserve_integer_keys
* (optional) If given, integer keys will be preserved and merged instead of
* appended. Defaults to FALSE.
*
* @return array
* The merged array.
*
* @see NestedArray::mergeDeep()
*/
public static function mergeDeepArray(array $arrays, $preserve_integer_keys = FALSE) {
$result = array();
foreach ($arrays as $array) {
foreach ($array as $key => $value) {
// Renumber integer keys as array_merge_recursive() does unless
// $preserve_integer_keys is set to TRUE. Note that PHP automatically
// converts array keys that are integer strings (e.g., '1') to integers.
if (is_integer($key) && !$preserve_integer_keys) {
$result[] = $value;
}
// Recurse when both values are arrays.
elseif (isset($result[$key]) && is_array($result[$key]) && is_array($value)) {
$result[$key] = self::mergeDeepArray(array($result[$key], $value), $preserve_integer_keys);
}
// Otherwise, use the latter value, overriding any previous value.
else {
$result[$key] = $value;
}
}
}
return $result;
}
}