RUBY-946 Use bulk write API for inserting GridFS file chunks

Author: estolfo

lib/mongo/grid/fs.rb

@@ -75,12 +75,12 @@ def find_one(selector = nil)
       # @since 2.0.0
       def insert_one(file)
         files_collection.insert_one(file.metadata)
-        result = chunks_collection.insert_many(file.chunks)
-        if write_concern.get_last_error
-          validate_md5!(file)
-        else
-          result
+        inserts = file.chunks.reduce([]) do |ops, chunk|
+          ops << { :insert_one => chunk }
         end
+        result = chunks_collection.bulk_write(inserts, ordered: true)
+        validate_md5!(file) if write_concern.get_last_error
+        result
       end
 
       # Create the GridFS.

spec/mongo/grid/fs_spec.rb

@@ -101,6 +101,33 @@
         }.to raise_error(Mongo::Error::OperationFailure)
       end
     end
+
+    context 'when the file exceeds the max bson size' do
+
+      let(:fs) do
+        described_class.new(authorized_client.database)
+      end
+
+      let(:file) do
+        str = 'y' * 16777216
+        Mongo::Grid::File.new(str, :filename => 'large-file.txt')
+      end
+
+      before do
+        fs.insert_one(file)
+      end
+
+      after do
+        fs.files_collection.find.delete_many
+        fs.chunks_collection.find.delete_many
+      end
+
+      it 'successfully inserts the file' do
+        expect(
+          fs.find_one(:filename => 'large-file.txt').chunks
+        ).to eq(file.chunks)
+      end
+    end
   end
 
   describe '#delete_one' do