[WIP] Feature/item persister and retriever

src/MetaModels/DataAccess/DatabaseHelperTrait.php

@@ -0,0 +1,39 @@
+<?php
+
+/**
+ * This file is part of MetaModels/core.
+ *
+ * (c) 2012-2017 The MetaModels team.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ *
+ * This project is provided in good faith and hope to be usable by anyone.
+ *
+ * @package    MetaModels
+ * @subpackage Core
+ * @author     Christian Schiffler <[email protected]>
+ * @copyright  2012-2017 The MetaModels team.
+ * @license    https://github.com/MetaModels/core/blob/master/LICENSE LGPL-3.0
+ * @filesource
+ */
+
+namespace MetaModels\DataAccess;
+
+/**
+ * This trait provides some helper functions for database access.
+ */
+trait DatabaseHelperTrait
+{
+    /**
+     * Build a list of the correct amount of "?" for use in a db query.
+     *
+     * @param array $parameters The parameters.
+     *
+     * @return string
+     */
+    private function buildDatabaseParameterList(array $parameters)
+    {
+        return implode(',', array_fill(0, count($parameters), '?'));
+    }
+}

src/MetaModels/DataAccess/IdResolver.php

@@ -0,0 +1,340 @@
+<?php
+
+/**
+ * This file is part of MetaModels/core.
+ *
+ * (c) 2012-2017 The MetaModels team.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ *
+ * This project is provided in good faith and hope to be usable by anyone.
+ *
+ * @package    MetaModels
+ * @subpackage Core
+ * @author     Christian Schiffler <[email protected]>
+ * @copyright  2012-2017 The MetaModels team.
+ * @license    https://github.com/MetaModels/core/blob/master/LICENSE LGPL-3.0
+ * @filesource
+ */
+
+namespace MetaModels\DataAccess;
+
+use Contao\Database;
+use MetaModels\Filter\IFilter;
+use MetaModels\IMetaModel;
+
+/**
+ * This class resolves an id list.
+ */
+class IdResolver
+{
+    use DatabaseHelperTrait;
+
+    /**
+     * The database.
+     *
+     * @var Database
+     */
+    private $database;
+
+    /**
+     * The metamodel we work on.
+     *
+     * @var IMetaModel
+     */
+    private $metaModel;
+
+    /**
+     * The MetaModel table name.
+     *
+     * @var string
+     */
+    private $tableName;
+
+    /**
+     * The filter.
+     *
+     * @var IFilter
+     */
+    private $filter;
+
+    /**
+     * The sort attribute.
+     *
+     * @var string
+     */
+    private $sortBy;
+
+    /**
+     * The sort order.
+     *
+     * @var string
+     */
+    private $sortOrder = 'ASC';
+
+    /**
+     * The offset.
+     *
+     * @var int
+     */
+    private $offset = 0;
+
+    /**
+     * The limit.
+     *
+     * @var int
+     */
+    private $limit = 0;
+
+    /**
+     * Create a new instance.
+     *
+     * @param IMetaModel $metaModel The MetaModel.
+     * @param Database   $database  The database.
+     */
+    public function __construct(IMetaModel $metaModel, Database $database)
+    {
+        $this->database  = $database;
+        $this->metaModel = $metaModel;
+        $this->tableName = $metaModel->getTableName();
+    }
+
+    /**
+     * Create a new instance.
+     *
+     * @param IMetaModel $metaModel The MetaModel.
+     * @param Database   $database  The database.
+     *
+     * @return IdResolver
+     */
+    public static function create(IMetaModel $metaModel, Database $database)
+    {
+        return new static($metaModel, $database);
+    }
+
+    /**
+     * Retrieve filter.
+     *
+     * @return IFilter
+     */
+    public function getFilter()
+    {
+        return $this->filter;
+    }
+
+    /**
+     * Set filter.
+     *
+     * @param IFilter $filter The new value.
+     *
+     * @return IdResolver
+     */
+    public function setFilter(IFilter $filter = null)
+    {
+        $this->filter = $filter;
+
+        return $this;
+    }
+
+    /**
+     * Retrieve attribute.
+     *
+     * @return string
+     */
+    public function getSortBy()
+    {
+        return $this->sortBy;
+    }
+
+    /**
+     * Set attribute.
+     *
+     * @param string $sortBy The new value.
+     *
+     * @return IdResolver
+     */
+    public function setSortBy($sortBy)
+    {
+        $this->sortBy = (string) $sortBy;
+
+        return $this;
+    }
+
+    /**
+     * Retrieve sort order.
+     *
+     * @return string
+     */
+    public function getSortOrder()
+    {
+        return $this->sortOrder;
+    }
+
+    /**
+     * Set sort order.
+     *
+     * @param string $sortOrder The new value.
+     *
+     * @return IdResolver
+     */
+    public function setSortOrder($sortOrder)
+    {
+        $this->sortOrder = $sortOrder == 'DESC' ? 'DESC' : 'ASC';
+
+        return $this;
+    }
+
+    /**
+     * Retrieve offset.
+     *
+     * @return int
+     */
+    public function getOffset()
+    {
+        return $this->offset;
+    }
+
+    /**
+     * Set offset.
+     *
+     * @param int $offset The new value.
+     *
+     * @return IdResolver
+     */
+    public function setOffset($offset)
+    {
+        $this->offset = (int) $offset;
+
+        return $this;
+    }
+
+    /**
+     * Retrieve limit.
+     *
+     * @return int
+     */
+    public function getLimit()
+    {
+        return $this->limit;
+    }
+
+    /**
+     * Set limit.
+     *
+     * @param int $limit The new value.
+     *
+     * @return IdResolver
+     */
+    public function setLimit($limit)
+    {
+        $this->limit = (int) $limit;
+
+        return $this;
+    }
+
+    /**
+     * Retrieve the id list.
+     *
+     * @return string[]
+     */
+    public function getIds()
+    {
+        if ([] === $filteredIds = array_filter($this->getMatchingIds())) {
+            return [];
+        }
+
+        // If desired, sort the entries.
+        if (!empty($filteredIds) && null !== $this->sortBy) {
+            $filteredIds = $this->sortIds($filteredIds);
+        }
+
+        // Apply limiting then.
+        if ($this->offset > 0 || $this->limit > 0) {
+            $filteredIds = array_slice($filteredIds, $this->offset, $this->limit ?: null);
+        }
+        return array_unique(array_filter($filteredIds));
+    }
+
+    /**
+     * Fetch the amount of matching items.
+     *
+     * @return int
+     */
+    public function count()
+    {
+        $filteredIds = $this->getMatchingIds();
+        if (count($filteredIds) == 0) {
+            return 0;
+        }
+
+        $result = $this
+            ->database
+            ->prepare(sprintf(
+                'SELECT COUNT(id) AS count FROM %s WHERE id IN(%s)',
+                $this->tableName,
+                $this->buildDatabaseParameterList($filteredIds)
+            ))
+            ->execute($filteredIds);
+
+        return $result->count;
+    }
+
+    /**
+     * Narrow down the list of Ids that match the given filter.
+     *
+     * @return array all matching Ids.
+     */
+    private function getMatchingIds()
+    {
+        if (null !== $this->filter && null !== ($matchingIds = $this->filter->getMatchingIds())) {
+            return $matchingIds;
+        }
+
+        // Either no filter object or all ids allowed => return all ids.
+        // if no id filter is passed, we assume all ids are provided.
+        $rows = $this->database->execute('SELECT id FROM ' . $this->tableName);
+
+        return $rows->fetchEach('id');
+    }
+
+    /**
+     * Sort the ids.
+     *
+     * @param string[] $filteredIds The id list.
+     *
+     * @return array
+     */
+    private function sortIds($filteredIds)
+    {
+        switch (true) {
+            case ('random' === $this->sortBy):
+                shuffle($filteredIds);
+                return $filteredIds;
+            case 'id':
+                asort($filteredIds);
+                return $filteredIds;
+            case (null !== ($attribute = $this->metaModel->getAttribute($this->sortBy))):
+                return $attribute->sortIds($filteredIds, $this->sortOrder);
+            case (in_array($this->sortBy, ['pid', 'tstamp', 'sorting'])):
+                // Sort by database values.
+                return $this
+                    ->database
+                    ->prepare(
+                        sprintf(
+                            'SELECT id FROM %s WHERE id IN(%s) ORDER BY %s %s',
+                            $this->tableName,
+                            $this->buildDatabaseParameterList($filteredIds),
+                            $this->sortBy,
+                            $this->sortOrder
+                        )
+                    )
+                    ->execute($filteredIds)
+                    ->fetchEach('id');
+            default:
+                // Nothing we can do about this.
+        }
+
+        return $filteredIds;
+    }
+}