Belongs to many relationship class added

src/Jenssegers/Mongodb/Relations/BelongsToMany.php

+<?php namespace Jenssegers\Mongodb\Relations;
+use Illuminate\Database\Eloquent\Collection;
+use Illuminate\Database\Eloquent\Builder;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsToMany as EloquentBelongsToMany;
+
+class BelongsToMany extends EloquentBelongsToMany {
+
+	/**
+	 * Execute the query as a "select" statement.
+	 *
+	 * @param  array  $columns
+	 * @return \Illuminate\Database\Eloquent\Collection
+	 */
+	public function get($columns = array('*'))
+	{
+		// First we'll add the proper select columns onto the query so it is run with
+		// the proper columns. Then, we will get the results and hydrate out pivot
+		// models with the result of those columns as a separate model relation.
+		$select = $this->getSelectColumns($columns);
+
+		$models = $this->query->addSelect($select)->getModels();
+
+		// If we actually found models we will also eager load any relationships that
+		// have been specified as needing to be eager loaded. This will solve the
+		// n + 1 query problem for the developer and also increase performance.
+		if (count($models) > 0)
+		{
+			$models = $this->query->eagerLoadRelations($models);
+		}
+
+		return $this->related->newCollection($models);
+	}
+	
+	/**
+	 * Set the select clause for the relation query.
+	 *
+	 * @return \Illuminate\Database\Eloquent\Relations\BelongsToMany
+	 */
+	protected function getSelectColumns(array $columns = array('*'))
+	{
+		return $columns;
+	}
+
+	/**
+	 * Get a paginator for the "select" statement.
+	 *
+	 * @param  int    $perPage
+	 * @param  array  $columns
+	 * @return \Illuminate\Pagination\Paginator
+	 */
+	public function paginate($perPage = null, $columns = array('*'))
+	{
+		$this->query->addSelect($this->getSelectColumns($columns));
+
+		// When paginating results, we need to add the pivot columns to the query and
+		// then hydrate into the pivot objects once the results have been gathered
+		// from the database since this isn't performed by the Eloquent builder.
+		$pager = $this->query->paginate($perPage, $columns);
+
+		return $pager;
+	}
+
+
+	/**
+	 * Set the base constraints on the relation query.
+	 *
+	 * @return void
+	 */
+	public function addConstraints()
+	{
+		if (static::$constraints) 
+		{
+			// Make sure that the primary key of the parent
+			// is in the relationship array of keys
+			$this->query->whereIn($this->foreignKey, array($this->parent->getKey()));
+		}
+	}
+
+	/**
+	 * Set the constraints for an eager load of the relation.
+	 *
+	 * @param  array  $models
+	 * @return void
+	 */
+	public function addEagerConstraints(array $models)
+	{
+		$this->query->whereIn($this->getForeignKey(), $this->getKeys($models));
+	}
+
+	/**
+	 * Save a new model and attach it to the parent model.
+	 *
+	 * @param  \Illuminate\Database\Eloquent\Model  $model
+	 * @param  array  $joining
+	 * @param  bool   $touch
+	 * @return \Illuminate\Database\Eloquent\Model
+	 */
+	public function save(Model $model, array $joining = array(), $touch = true)
+	{
+		$model->save(array('touch' => false));
+
+		$this->attach($model->getKey(), $joining, $touch);
+		
+		return $model;
+	}
+
+	/**
+	 * Create a new instance of the related model.
+	 *
+	 * @param  array  $attributes
+	 * @param  array  $joining
+	 * @param  bool   $touch
+	 * @return \Illuminate\Database\Eloquent\Model
+	 */
+	public function create(array $attributes, array $joining = array(), $touch = true)
+	{
+		$instance = $this->related->newInstance($attributes);
+
+		// Save the new instance before we attach it to other models	
+		$instance->save(array('touch' => false));
+		
+		// Attach to the parent instance
+		$this->attach($instance->_id, $attributes, $touch);
+
+		return $instance;
+	}
+
+	/**
+	 * Sync the intermediate tables with a list of IDs.
+	 *
+	 * @param  array  $ids
+	 * @param  bool   $detaching
+	 * @return void
+	 */
+	public function sync(array $ids, $detaching = true)
+	{
+		// First we need to attach any of the associated models that are not currently
+		// in this joining table. We'll spin through the given IDs, checking to see
+		// if they exist in the array of current ones, and if not we will insert.
+		$current = $this->parent->{$this->otherKey};
+		
+		// Check if the current array exists or not on the parent model and create it
+		// if it does not exist
+		if (is_null($current)) $current = array();
+
+		$records = $this->formatSyncList($ids);
+		
+		$detach = array_diff($current, array_keys($records));
+
+		// Next, we will take the differences of the currents and given IDs and detach
+		// all of the entities that exist in the "current" array but are not in the
+		// the array of the IDs given to the method which will complete the sync.
+		if ($detaching and count($detach) > 0)
+		{
+			$this->detach($detach);
+		}
+
+		// Now we are finally ready to attach the new records. Note that we'll disable
+		// touching until after the entire operation is complete so we don't fire a
+		// ton of touch operations until we are totally done syncing the records.
+		$this->attachNew($records, $current, false);
+
+		$this->touchIfTouching();
+	}
+
+	/**
+	 * Format the sync list so that it is keyed by ID.
+	 *
+	 * @param  array  $records
+	 * @return array
+	 */
+	protected function formatSyncList(array $records)
+	{
+		$results = array();
+
+		foreach ($records as $id => $attributes)
+		{
+			if ( ! is_array($attributes))
+			{
+				list($id, $attributes) = array($attributes, array());
+			}
+
+			$results[$id] = $attributes;
+		}
+
+		return $results;
+	}
+
+	/**
+	 * Attach all of the IDs that aren't in the current array.
+	 *
+	 * @param  array  $records
+	 * @param  array  $current
+	 * @param  bool   $touch
+	 * @return void
+	 */
+	protected function attachNew(array $records, array $current, $touch = true)
+	{
+		foreach ($records as $id => $attributes)
+		{
+			// If the ID is not in the list of existing pivot IDs, we will insert a new pivot
+			// record, otherwise, we will just update this existing record on this joining
+			// table, so that the developers will easily update these records pain free.
+			if ( ! in_array($id, $current))
+			{
+				$this->attach($id, $attributes, $touch);
+			}
+		}
+	}
+
+	/**
+	 * Attach a model to the parent.
+	 *
+	 * @param  mixed  $id
+	 * @param  array  $attributes
+	 * @param  bool   $touch
+	 * @return void
+	 */
+	public function attach($id, array $attributes = array(), $touch = true)
+	{
+		if ($id instanceof Model) $id = $id->getKey();
+		
+		// Generate a new parent query instance
+		$parent = $this->newParentQuery();
+		
+		// Generate a new related query instance
+		$related = $this->related->newInstance();
+		
+		// Set contraints on the related query
+		$related = $related->where($this->related->getKeyName(), $id);
+
+		$records = $this->createAttachRecords((array) $id, $attributes);
+		
+		// Get the ID's to attach to the two documents
+		$otherIds = array_pluck($records, $this->otherKey);
+		$foreignIds = array_pluck($records, $this->foreignKey);
+
+		// Attach to the parent model
+		$parent->push($this->otherKey, $otherIds[0])->update(array());
+		
+		// Attach to the related model
+		$related->push($this->foreignKey, $foreignIds[0])->update(array());
+	}
+
+	/**
+	 * Create an array of records to insert into the pivot table.
+	 *
+	 * @param  array  $ids
+	 * @return void
+	 */
+	protected function createAttachRecords($ids, array $attributes)
+	{
+		$records = array();;
+
+		// To create the attachment records, we will simply spin through the IDs given
+		// and create a new record to insert for each ID. Each ID may actually be a
+		// key in the array, with extra attributes to be placed in other columns.
+		foreach ($ids as $key => $value)
+		{
+			$records[] = $this->attacher($key, $value, $attributes, false);
+		}
+
+		return $records;
+	}
+
+	/**
+	 * Detach models from the relationship.
+	 *
+	 * @param  int|array  $ids
+	 * @param  bool  $touch
+	 * @return int
+	 */
+	public function detach($ids = array(), $touch = true)
+	{
+		if ($ids instanceof Model) $ids = (array) $ids->getKey();
+
+		$query = $this->newParentQuery();
+
+		// If associated IDs were passed to the method we will only delete those
+		// associations, otherwise all of the association ties will be broken.
+		// We'll return the numbers of affected rows when we do the deletes.
+		$ids = (array) $ids;
+
+		if (count($ids) > 0)
+		{
+			$query->whereIn($this->otherKey, $ids);
+		}
+
+		if ($touch) $this->touchIfTouching();
+
+		// Once we have all of the conditions set on the statement, we are ready
+		// to run the delete on the pivot table. Then, if the touch parameter
+		// is true, we will go ahead and touch all related models to sync.
+		foreach($ids as $id)
+		{
+			$query->pull($this->otherKey, $id);
+		}
+		
+		return count($ids);
+	}
+
+	/**
+	 * If we're touching the parent model, touch.
+	 *
+	 * @return void
+	 */
+	public function touchIfTouching()
+	{ 
+	 	if ($this->touchingParent()) $this->getParent()->touch();
+
+	 	if ($this->getParent()->touches($this->relationName)) $this->touch();
+	}
+
+	/**
+	 * Determine if we should touch the parent on sync.
+	 *
+	 * @return bool
+	 */
+	protected function touchingParent()
+	{
+		return $this->getRelated()->touches($this->guessInverseRelation());
+	}
+
+	/**
+	 * Attempt to guess the name of the inverse of the relation.
+	 *
+	 * @return string
+	 */
+	protected function guessInverseRelation()
+	{
+		return strtolower(str_plural(class_basename($this->getParent())));
+	}
+
+	/**
+	 * Create a new query builder for the parent
+	 * 
+	 * @return Jenssegers\Mongodb\Builder
+	 */
+	protected function newParentQuery()
+	{
+		$query = $this->parent->newQuery();
+		
+		return $query->where($this->parent->getKeyName(), '=', $this->parent->getKey());
+	}
+	
+	/**
+	 * Build model dictionary keyed by the relation's foreign key.
+	 *
+	 * @param  \Illuminate\Database\Eloquent\Collection  $results
+	 * @return array
+	 */
+	protected function buildDictionary(Collection $results)
+	{
+		$foreign = $this->foreignKey;
+
+		// First we will build a dictionary of child models keyed by the foreign key
+		// of the relation so that we will easily and quickly match them to their
+		// parents without having a possibly slow inner loops for every models.
+		$dictionary = array();
+
+		foreach ($results as $result)
+		{
+			foreach ($result->$foreign as $single)
+			{
+				$dictionary[$single][] = $result;
+			}
+		}
+
+		return $dictionary;
+	}
+
+	/**
+	 * Get the related model's updated at column name.
+	 *
+	 * @return string
+	 */
+	public function getRelatedFreshUpdate()
+	{
+		return array($this->related->getUpdatedAtColumn() => $this->related->freshTimestamp());
+	}
+
+	/**
+	 * Get the fully qualified foreign key for the relation.
+	 *
+	 * @return string
+	 */
+	public function getForeignKey()
+	{
+		return $this->foreignKey;
+	}
+
+	/**
+	 * Get the fully qualified "other key" for the relation.
+	 *
+	 * @return string
+	 */
+	public function getOtherKey()
+	{
+		return $this->otherKey;
+	}
+}
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