Added missing engine methods.

src/DatabaseEngine.php

@@ -5,6 +5,7 @@
 use Illuminate\Database\DatabaseManager;
 use Illuminate\Database\Eloquent\SoftDeletes;
 use Illuminate\Support\Collection;
+use Illuminate\Support\LazyCollection;
 use Laravel\Scout\Builder;
 use Laravel\Scout\Engines\Engine;
 
@@ -155,6 +156,58 @@ public function map(Builder $builder, $results, $model)
             })->filter();
     }
 
+    /**
+     * Map the given results to instances of the given model via a lazy collection.
+     *
+     * @param  \Laravel\Scout\Builder  $builder
+     * @param  mixed  $results
+     * @param  \Illuminate\Database\Eloquent\Model  $model
+     * @return \Illuminate\Support\LazyCollection
+     */
+    public function lazyMap(Builder $builder, $results, $model)
+    {
+        return LazyCollection::make(function() use ($results, $model) {
+            $chunks = collect($this->mapIds($results))->chunk(1000);
+
+            foreach ($chunks as $chunk) {
+                foreach ($chunk as $item) {
+                    $query = $model->query();
+
+                    if ($this->usesSoftDelete($model)) {
+                        $query = $query->withTrashed();
+                    }
+
+                    if ($result = $query->find($item)) {
+                        yield $result;
+                    }
+                };
+            };
+        });
+    }
+
+    /**
+     * Create a search index.
+     *
+     * @param  string  $name
+     * @param  array  $options
+     * @return mixed
+     */
+    public function createIndex($name, array $options = [])
+    {
+        throw new Exception('Database indexes are created automatically upon adding objects.');
+    }
+
+    /**
+     * Delete a search index.
+     *
+     * @param  string  $name
+     * @return mixed
+     */
+    public function deleteIndex($name)
+    {
+        $this->query()->where('index', $name)->delete();
+    }
+
     /**
      * Get the total count from a raw result returned by the engine.
      *

tests/DatabaseEngineTest.php

@@ -165,6 +165,47 @@ public function test_map_correctly_maps_empty()
         $this->assertCount(0, $results);
     }
 
+    public function test_lazy_map_correctly_maps_results_to_models()
+    {
+        $manager = Mockery::mock('Illuminate\Database\DatabaseManager');
+        $queryBuilder = Mockery::mock('\Illuminate\Database\Query\Builder');
+        $manager->shouldReceive('table')->with('scout_index')->andReturn($queryBuilder);
+
+        $model = Mockery::mock('StdClass');
+        $model->shouldReceive('query')->andReturn($model);
+        $model->shouldReceive('find')->with(1)->andReturn($model);
+
+        $builder = Mockery::mock(Builder::class);
+
+        $record = new \StdClass();
+        $record->objectID = 1;
+
+        $engine = new DatabaseEngine($manager);
+        $results = $engine->lazyMap($builder, ['results' => collect([
+           $record,
+        ]), 'total' => 1], $model);
+
+        $this->assertEquals(1, $results->count());
+    }
+
+    public function test_lazy_map_correctly_maps_empty()
+    {
+        $manager = Mockery::mock('Illuminate\Database\DatabaseManager');
+        $queryBuilder = Mockery::mock('\Illuminate\Database\Query\Builder');
+        $manager->shouldReceive('table')->with('scout_index')->andReturn($queryBuilder);
+
+        $model = Mockery::mock('StdClass');
+        $model->shouldReceive('query')->andReturn($model);
+        $model->shouldReceive('find')->with(1)->andReturn($model);
+
+        $builder = Mockery::mock(Builder::class);
+
+        $engine = new DatabaseEngine($manager);
+        $results = $engine->lazyMap($builder, ['results' => collect([]), 'total' => 0], $model);
+
+        $this->assertEquals(0, $results->count());
+    }
+
     public function test_paginate_returns_correctly()
     {
         $queryBuilder = Mockery::mock('\Illuminate\Database\Query\Builder');