drupal/includes/entity.inc

301 lines
11 KiB
PHP

<?php
// $Id$
/**
* Interface for entity controller classes.
*
* All entity controller classes specified via the 'controller class' key
* returned by hook_entity_info() or hook_entity_info_alter() have to implement
* this interface.
*
* Most simple, SQL-based entity controllers will do better by extending
* DrupalDefaultEntityController instead of implementing this interface
* directly.
*/
interface DrupalEntityControllerInterface {
/**
* Constructor.
*
* @param $entityType
* The entity type for which the instance is created.
*/
public function __construct($entityType);
/**
* Reset the internal, static entity cache.
*/
public function resetCache();
/**
* Load one or more entities.
*
* @param $ids
* An array of entity IDs, or FALSE to load all entities.
* @param $conditions
* An array of conditions in the form 'field' => $value.
*
* @return
* An array of entity objects indexed by their ids.
*/
public function load($ids = array(), $conditions = array());
}
/**
* Default implementation of DrupalEntityControllerInterface.
*
* This class can be used as-is by most simple entity types. Entity types
* requiring special handling can extend the class.
*/
class DrupalDefaultEntityController implements DrupalEntityControllerInterface {
protected $entityCache;
protected $entityType;
protected $entityInfo;
protected $hookLoadArguments;
protected $idKey;
protected $revisionKey;
protected $revisionTable;
protected $query;
/**
* Constructor. Set basic variables.
*/
public function __construct($entityType) {
$this->entityType = $entityType;
$this->entityInfo = entity_get_info($entityType);
$this->entityCache = array();
$this->hookLoadArguments = array();
$this->idKey = $this->entityInfo['object keys']['id'];
// Check if the entity type supports revisions.
if (!empty($this->entityInfo['object keys']['revision'])) {
$this->revisionKey = $this->entityInfo['object keys']['revision'];
$this->revisionTable = $this->entityInfo['revision table'];
}
else {
$this->revisionKey = FALSE;
}
// Check if the entity type supports static caching of loaded entities.
$this->cache = !empty($this->entityInfo['static cache']);
}
public function resetCache() {
$this->entityCache = array();
}
public function load($ids = array(), $conditions = array()) {
$this->ids = $ids;
$this->conditions = $conditions;
$entities = array();
// Revisions are not statically cached, and require a different query to
// other conditions, so separate the revision id into its own variable.
if ($this->revisionKey && isset($this->conditions[$this->revisionKey])) {
$this->revisionId = $this->conditions[$this->revisionKey];
unset($this->conditions[$this->revisionKey]);
}
else {
$this->revisionId = FALSE;
}
// Create a new variable which is either a prepared version of the $ids
// array for later comparison with the entity cache, or FALSE if no $ids
// were passed. The $ids array is reduced as items are loaded from cache,
// and we need to know if it's empty for this reason to avoid querying the
// database when all requested entities are loaded from cache.
$passed_ids = !empty($this->ids) ? array_flip($this->ids) : FALSE;
// Try to load entities from the static cache, if the entity type supports
// static caching.
if ($this->cache) {
$entities += $this->cacheGet($this->ids, $this->conditions);
// If any entities were loaded, remove them from the ids still to load.
if ($passed_ids) {
$this->ids = array_keys(array_diff_key($passed_ids, $entities));
}
}
// Load any remaining entities from the database. This is the case if $ids
// is set to FALSE (so we load all entities), if there are any ids left to
// load, if loading a revision, or if $conditions was passed without $ids.
if ($this->ids === FALSE || $this->ids || $this->revisionId || ($this->conditions && !$passed_ids)) {
// Build the query.
$this->buildQuery();
$queried_entities = $this->query
->execute()
->fetchAllAssoc($this->idKey);
}
// Pass all entities loaded from the database through $this->attachLoad(),
// which attaches fields (if supported by the entity type) and calls the
// entity type specific load callback, for example hook_node_load().
if (!empty($queried_entities)) {
$this->attachLoad($queried_entities);
$entities += $queried_entities;
}
if ($this->cache) {
// Add entities to the cache if we are not loading a revision.
if (!empty($queried_entities) && !$this->revisionId) {
$this->cacheSet($queried_entities);
}
}
// Ensure that the returned array is ordered the same as the original
// $ids array if this was passed in and remove any invalid ids.
if ($passed_ids) {
// Remove any invalid ids from the array.
$passed_ids = array_intersect_key($passed_ids, $entities);
foreach ($entities as $entity) {
$passed_ids[$entity->{$this->idKey}] = $entity;
}
$entities = $passed_ids;
}
return $entities;
}
/**
* Build the query to load the entity.
*
* This has full revision support. For entities requiring special queries,
* the class can be extended, and the default query can be constructed by
* calling parent::buildQuery(). This is usually necessary when the object
* being loaded needs to be augmented with additional data from another
* table, such as loading node type into comments or vocabulary machine name
* into terms, however it can also support $conditions on different tables.
* See NodeController::buildQuery() or TaxonomyTermController::buildQuery()
* for examples.
*/
protected function buildQuery() {
$this->query = db_select($this->entityInfo['base table'], 'base');
$this->query->addTag($this->entityType . '_load_multiple');
if ($this->revisionId) {
$this->query->join($this->revisionTable, 'revision', "revision.{$this->idKey} = base.{$this->idKey} AND revision.{$this->revisionKey} = :revisionId", array(':revisionId' => $this->revisionId));
}
elseif ($this->revisionKey) {
$this->query->join($this->revisionTable, 'revision', "revision.{$this->revisionKey} = base.{$this->revisionKey}");
}
// Add fields from the {entity} table.
$entity_fields = drupal_schema_fields_sql($this->entityInfo['base table']);
if ($this->revisionKey) {
// Add all fields from the {entity_revision} table.
$entity_revision_fields = drupal_map_assoc(drupal_schema_fields_sql($this->revisionTable));
// The id field is provided by entity, so remove it.
unset($entity_revision_fields[$this->idKey]);
// Change timestamp to revision_timestamp, and revision uid to
// revision_uid before adding them to the query.
// TODO: This is node specific and has to be moved into NodeController.
unset($entity_revision_fields['timestamp']);
$this->query->addField('revision', 'timestamp', 'revision_timestamp');
unset($entity_revision_fields['uid']);
$this->query->addField('revision', 'uid', 'revision_uid');
// Remove all fields from the base table that are also fields by the same
// name in the revision table.
$entity_field_keys = array_flip($entity_fields);
foreach ($entity_revision_fields as $key => $name) {
if (isset($entity_field_keys[$name])) {
unset($entity_fields[$entity_field_keys[$name]]);
}
}
$this->query->fields('revision', $entity_revision_fields);
}
$this->query->fields('base', $entity_fields);
if ($this->ids) {
$this->query->condition("base.{$this->idKey}", $this->ids, 'IN');
}
if ($this->conditions) {
foreach ($this->conditions as $field => $value) {
$this->query->condition('base.' . $field, $value);
}
}
}
/**
* Attach data to entities upon loading.
*
* This will attach fields, if the entity is fieldable. It calls
* hook_entity_load() for modules which need to add data to all entities.
* It also calls hook_TYPE_load() on the loaded entities. For example
* hook_node_load() or hook_user_load(). If your hook_TYPE_load()
* expects special parameters apart from the queried entities, you can set
* $this->hookLoadArguments prior to calling the method.
* See NodeController::attachLoad() for an example.
*/
protected function attachLoad(&$queried_entities) {
// Attach fields.
if ($this->entityInfo['fieldable']) {
if ($this->revisionId) {
field_attach_load_revision($this->entityType, $queried_entities);
}
else {
field_attach_load($this->entityType, $queried_entities);
}
}
// Call hook_entity_load().
foreach (module_implements('entity_load') as $module) {
$function = $module . '_entity_load';
$function($queried_entities, $this->entityType);
}
// Call hook_TYPE_load(). The first argument for hook_TYPE_load() are
// always the queried entities, followed by additional arguments set in
// $this->hookLoadArguments.
$args = array_merge(array($queried_entities), $this->hookLoadArguments);
foreach (module_implements($this->entityInfo['load hook']) as $module) {
call_user_func_array($module . '_' . $this->entityInfo['load hook'], $args);
}
}
/**
* Get entities from the static cache.
*
* @param $ids
* If not empty, return entities that match these IDs.
* @param $conditions
* If set, return entities that match all of these conditions.
*/
protected function cacheGet($ids, $conditions = array()) {
$entities = array();
// Load any available entities from the internal cache.
if (!empty($this->entityCache) && !$this->revisionId) {
if ($ids) {
$entities += array_intersect_key($this->entityCache, array_flip($ids));
}
// If loading entities only by conditions, fetch all available entities
// from the cache. Entities which don't match are removed later.
elseif ($conditions) {
$entities = $this->entityCache;
}
}
// Exclude any entities loaded from cache if they don't match $conditions.
// This ensures the same behavior whether loading from memory or database.
if ($conditions) {
foreach ($entities as $entity) {
$entity_values = (array) $entity;
if (array_diff_assoc($conditions, $entity_values)) {
unset($entities[$entity->{$this->idKey}]);
}
}
}
return $entities;
}
/**
* Store entities in the static entity cache.
*/
protected function cacheSet($entities) {
$this->entityCache += $entities;
}
}