newline battles continue

vendor/go.mongodb.org/mongo-driver/mongo/single_result.go

@@ -0,0 +1,93 @@
+// Copyright (C) MongoDB, Inc. 2017-present.
+//
+// Licensed under the Apache License, Version 2.0 (the "License"); you may
+// not use this file except in compliance with the License. You may obtain
+// a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
+
+package mongo
+
+import (
+	"context"
+	"errors"
+
+	"go.mongodb.org/mongo-driver/bson"
+	"go.mongodb.org/mongo-driver/bson/bsoncodec"
+)
+
+// ErrNoDocuments is returned by Decode when an operation that returns a
+// SingleResult doesn't return any documents.
+var ErrNoDocuments = errors.New("mongo: no documents in result")
+
+// SingleResult represents a single document returned from an operation. If
+// the operation returned an error, the Err method of SingleResult will
+// return that error.
+type SingleResult struct {
+	err error
+	cur *Cursor
+	rdr bson.Raw
+	reg *bsoncodec.Registry
+}
+
+// Decode will attempt to decode the first document into v. If there was an
+// error from the operation that created this SingleResult then the error
+// will be returned. If there were no returned documents, ErrNoDocuments is
+// returned. If v is nil or is a typed nil, an error will be returned.
+func (sr *SingleResult) Decode(v interface{}) error {
+	if sr.err != nil {
+		return sr.err
+	}
+	if sr.reg == nil {
+		return bson.ErrNilRegistry
+	}
+
+	if sr.err = sr.setRdrContents(); sr.err != nil {
+		return sr.err
+	}
+	return bson.UnmarshalWithRegistry(sr.reg, sr.rdr, v)
+}
+
+// DecodeBytes will return a copy of the document as a bson.Raw. If there was an
+// error from the operation that created this SingleResult then the error
+// will be returned. If there were no returned documents, ErrNoDocuments is
+// returned.
+func (sr *SingleResult) DecodeBytes() (bson.Raw, error) {
+	if sr.err != nil {
+		return nil, sr.err
+	}
+
+	if sr.err = sr.setRdrContents(); sr.err != nil {
+		return nil, sr.err
+	}
+	return sr.rdr, nil
+}
+
+// setRdrContents will set the contents of rdr by iterating the underlying cursor if necessary.
+func (sr *SingleResult) setRdrContents() error {
+	switch {
+	case sr.err != nil:
+		return sr.err
+	case sr.rdr != nil:
+		return nil
+	case sr.cur != nil:
+		defer sr.cur.Close(context.TODO())
+		if !sr.cur.Next(context.TODO()) {
+			if err := sr.cur.Err(); err != nil {
+				return err
+			}
+
+			return ErrNoDocuments
+		}
+		sr.rdr = sr.cur.Current
+		return nil
+	}
+
+	return ErrNoDocuments
+}
+
+// Err will return the error from the operation that created this SingleResult.
+// If there was no error, nil is returned.
+func (sr *SingleResult) Err() error {
+	sr.err = sr.setRdrContents()
+
+	return sr.err
+}