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Diffstat (limited to 'src/mongo/idl/basic_types.h')
-rw-r--r-- | src/mongo/idl/basic_types.h | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/src/mongo/idl/basic_types.h b/src/mongo/idl/basic_types.h new file mode 100644 index 00000000000..8eb66c53629 --- /dev/null +++ b/src/mongo/idl/basic_types.h @@ -0,0 +1,107 @@ +/** + * Copyright (C) 2019 MongoDB, Inc. + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the Server Side Public License, version 1, + * as published by MongoDB, Inc. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * Server Side Public License for more details. + * + * You should have received a copy of the Server Side Public License + * along with this program. If not, see + * <http://www.mongodb.com/licensing/server-side-public-license>. + * + * As a special exception, the copyright holders give permission to link the + * code of portions of this program with the OpenSSL library under certain + * conditions as described in each individual source file and distribute + * linked combinations including the program with the OpenSSL library. You + * must comply with the Server Side Public License in all respects for + * all of the code used other than as permitted herein. If you modify file(s) + * with this exception, you may extend this exception to your version of the + * file(s), but you are not obligated to do so. If you do not wish to do so, + * delete this exception statement from your version. If you delete this + * exception statement from all source files in the program, then also delete + * it in the license file. + */ + +#pragma once + +#include <boost/optional.hpp> + +#include "mongo/base/string_data.h" +#include "mongo/bson/bsonobjbuilder.h" + +namespace mongo { + +/** + * Wraps a boost::optional<bool> to provide consistent semantics. A standard boost::optional<bool> + * can introduce ambiguity because its 'operator bool' will resolve to 'true' if the optional is + * populated, even if is populated with boolean 'false'. By contrast, an instance of this class + * always resolves to the populated value, or false if not yet populated. This class will also + * serialize to BSON via the IDL only if the value has been explicitly set. + */ +class OptionalBool { +public: + static OptionalBool parseFromBSON(BSONElement element) { + uassert(ErrorCodes::BadValue, + str::stream() << "Field '" << element.fieldNameStringData() + << "' should be a boolean value, but found: " << element.type(), + !element || element.type() == BSONType::Bool); + return element ? OptionalBool{element.boolean()} : OptionalBool{}; + } + + OptionalBool(boost::optional<bool> value) : _value(std::move(value)) {} + OptionalBool(bool value) : _value(value) {} + + OptionalBool() : OptionalBool(boost::none) {} + + /** + * Returns true only if _value is populated with a value of true. + */ + operator bool() const { + return _value.value_or(false); + } + + /** + * Returns true if the value has been populated, false otherwise. + */ + bool has_value() const { + return _value.has_value(); + } + + /** + * Serialize this object as a field in a document. If _value is empty, omit the field. + */ + void serializeToBSON(StringData fieldName, BSONObjBuilder* builder) const { + if (_value) { + builder->appendBool(fieldName, *_value); + } + } + + /** + * Serialize this object as an element of a BSON array. If _value is empty, omit the entry. + */ + void serializeToBSON(BSONArrayBuilder* builder) const { + if (_value) { + builder->append(*_value); + } + } + + /** + * Returns a string representation of the current value. + */ + std::string toString() const { + return *this ? "1" : "0"; + } + operator std::string() const { + return toString(); + } + +private: + boost::optional<bool> _value; +}; + +} // namespace mongo |