#763376 follow-up by fago, sun, effulgentsia: Minor adjustments to drupal_array_set/get_nested_value().

3 files changed, 62 insertions, 46 deletions

diff --git a/includes/common.inc b/includes/common.inc
index 39606404e..ae308b001 100644
--- a/includes/common.inc
+++ b/includes/common.inc
@@ -5656,7 +5656,7 @@ function element_get_visible_children(array $elements) {
  *
  * @see drupal_array_get_nested_value()
  */
-function drupal_array_set_nested_value(&$array, $parents, $value) {
+function drupal_array_set_nested_value(array &$array, array $parents, $value) {
   $ref = &$array;
   foreach ($parents as $parent) {
     // Note that PHP is fine with referencing a not existing array key - in this
@@ -5669,8 +5669,8 @@ function drupal_array_set_nested_value(&$array, $parents, $value) {
 /**
  * Retrieves a value from a nested array with variable depth.
  *
- * This helper function should be used when the depth of the array element you
- * are changing may vary (that is, the number of parent keys is variable). It is
+ * This helper function should be used when the depth of the array element being
+ * retrieved may vary (that is, the number of parent keys is variable). It is
  * primarily used for form structures and renderable arrays.
  *
  * Without this helper function the only way to get a nested array value with
@@ -5683,14 +5683,23 @@ function drupal_array_set_nested_value(&$array, $parents, $value) {
  *
  * Instead, use this helper function:
  * @code
- * list($value, $value_exists) = drupal_array_get_nested_value($form, $parents);
- * if ($value_exists) {
+ * $value = drupal_array_get_nested_value($form, $parents);
+ * @endcode
+ *
+ * The return value will be NULL, regardless of whether the actual value is NULL
+ * or whether the requested key does not exist. 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;
+ * $value = drupal_array_get_nested_value($form, $parents, $value_exists);
+ * if ($key_exists) {
  *   // ... do something with $value ...
  * }
  * @endcode
  *
  * However if the number of array parent keys is static, the value should always
- * be get directly rather than calling this function. For instance:
+ * be retrieved directly rather than calling this function. For instance:
  * @code
  * $value = $form['signature_settings']['signature'];
  * @endcode
@@ -5699,34 +5708,54 @@ function drupal_array_set_nested_value(&$array, $parents, $value) {
  *   The array from which to get the value.
  * @param $parents
  *   An array of parent keys of the value, starting with the outermost key.
+ * @param &$key_exists
+ *   (optional) If given, an already defined variable that is altered by
+ *   reference.
  *
  * @return
- *   An indexed array containing:
- *   - The requested nested value, if it exists, or NULL if it does not.
- *   - TRUE if all the parent keys exist, FALSE otherwise.
+ *   The requested nested value. Possibly NULL if the value is NULL or not all
+ *   nested parent keys exist. $key_exists is altered by reference and is a
+ *   Boolean that indicates whether all nested parent keys exist (TRUE) or not
+ *   (FALSE). This allows to distinguish between the two possibilities when NULL
+ *   is returned.
  *
  * @see drupal_array_set_nested_value()
- * @see drupal_array_value_exists()
  */
-function drupal_array_get_nested_value($array, $parents) {
+function drupal_array_get_nested_value(array &$array, array $parents, &$key_exists = NULL) {
+  $ref = &$array;
   foreach ($parents as $parent) {
-    if (isset($array[$parent])) {
-      $array = $array[$parent];
+    // array_key_exists() is slower than isset() and triggers notices if the
+    // second argument is not an array, so only call it when absolutely
+    // necessary.
+    if (isset($ref[$parent]) || (is_array($ref) && array_key_exists($parent, $ref))) {
+      $ref = &$ref[$parent];
     }
     else {
-      return array(NULL, FALSE);
+      $key_exists = FALSE;
+      return NULL;
     }
   }
-  return array($array, TRUE);
+  $key_exists = TRUE;
+  return $ref;
 }
 
 /**
- * Determines whether a value in a nested array with variable depth exists.
+ * Determines whether a nested array with variable depth contains all of 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
- * drupal_array_set_nested_value() for details. This helper is primarily used
- * for form structures and renderable arrays.
+ * drupal_array_set_nested_value() 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
+ * drupal_array_get_nested_value() 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 $array
  *   The array with the value to check for.
@@ -5736,22 +5765,16 @@ function drupal_array_get_nested_value($array, $parents) {
  * @return
  *   TRUE if all the parent keys exist, FALSE otherwise.
  *
- * @see drupal_array_set_nested_value()
  * @see drupal_array_get_nested_value()
  */
-function drupal_array_nested_value_exists($array, $parents) {
-  foreach ($parents as $parent) {
-    if (isset($array[$parent])) {
-      $array = $array[$parent];
-    }
-    else {
-      return FALSE;
-    }
-  }
-  return TRUE;
+function drupal_array_nested_key_exists(array $array, array $parents) {
+  // Although this function is similar to PHP's array_key_exists(), its
+  // arguments should be consistent with drupal_array_get_nested_value().
+  $key_exists = NULL;
+  drupal_array_get_nested_value($array, $parents, $key_exists);
+  return $key_exists;
 }
 
-
 /**
  * Provide theme registration for themes across .inc files.
  */
diff --git a/includes/form.inc b/includes/form.inc
index f7ce97393..50e775199 100644
--- a/includes/form.inc
+++ b/includes/form.inc
@@ -1003,8 +1003,11 @@ function drupal_validate_form($form_id, &$form, &$form_state) {
   if (isset($form_state['triggering_element']['#limit_validation_errors']) && $form_state['triggering_element']['#limit_validation_errors'] !== FALSE) {
     $values = array();
     foreach ($form_state['triggering_element']['#limit_validation_errors'] as $section) {
-      list($value, $value_exists) = drupal_array_get_nested_value($form_state['values'], $section);
-      if ($value_exists) {
+      // If the section exists within $form_state['values'], even if the value
+      // is NULL, copy it to $values.
+      $section_exists = NULL;
+      $value = drupal_array_get_nested_value($form_state['values'], $section, $section_exists);
+      if ($section_exists) {
         drupal_array_set_nested_value($values, $section, $value);
       }
     }
@@ -1767,18 +1770,8 @@ function _form_builder_handle_input_element($form_id, &$element, &$form_state) {
     if ($process_input) {
       // Get the input for the current element. NULL values in the input need to
       // be explicitly distinguished from missing input. (see below)
-      $input = $form_state['input'];
-      $input_exists = TRUE;
-      foreach ($element['#parents'] as $parent) {
-        if (is_array($input) && array_key_exists($parent, $input)) {
-          $input = $input[$parent];
-        }
-        else {
-          $input = NULL;
-          $input_exists = FALSE;
-          break;
-        }
-      }
+      $input_exists = NULL;
+      $input = drupal_array_get_nested_value($form_state['input'], $element['#parents'], $input_exists);
       // For browser-submitted forms, the submitted values do not contain values
       // for certain elements (empty multiple select, unchecked checkbox).
       // During initial form processing, we add explicit NULL values for such
@@ -1850,7 +1843,7 @@ function _form_builder_handle_input_element($form_id, &$element, &$form_state) {
 
   // Set the element's value in $form_state['values'], but only, if its key
   // does not exist yet (a #value_callback may have already populated it).
-  if (!drupal_array_nested_value_exists($form_state['values'], $element['#parents'])) {
+  if (!drupal_array_nested_key_exists($form_state['values'], $element['#parents'])) {
     form_set_value($element, $element['#value'], $form_state);
   }
 }
diff --git a/modules/file/file.module b/modules/file/file.module
index bc0e292cc..a79c8f542 100644
--- a/modules/file/file.module
+++ b/modules/file/file.module
@@ -572,7 +572,7 @@ function file_managed_file_submit($form, &$form_state) {
   // and set $element to the managed_file element that contains that button.
   $parents = $form_state['triggering_element']['#array_parents'];
   $button_key = array_pop($parents);
-  list($element) = drupal_array_get_nested_value($form, $parents);
+  $element = drupal_array_get_nested_value($form, $parents);
 
   // No action is needed here for the upload button, because all file uploads on
   // the form are processed by file_managed_file_value() regardless of which