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/**
* Copyright (C) 2018-present 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 <memory>
// This file is included by many low-level headers including status.h, so it isn't able to include
// much without creating a cycle.
#include "mongo/base/error_codes.h"
#include "mongo/base/static_assert.h"
namespace mongo {
class BSONObj;
class BSONObjBuilder;
/**
* Base class for the extra info that can be attached to commands.
*
* Actual implementations must have a 'constexpr ErrorCode::Error code' to indicate which
* error code they bind to, and a static method with the following signature:
* static std::shared_ptr<const ErrorExtraInfo> parse(const BSONObj&);
* You must call the MONGO_INIT_REGISTER_ERROR_EXTRA_INFO(type) macro in the cpp file that contains
* the implementation for your subtype.
*/
class ErrorExtraInfo {
public:
using Parser = std::shared_ptr<const ErrorExtraInfo>(const BSONObj&);
ErrorExtraInfo() = default;
virtual ~ErrorExtraInfo() = default;
/**
* Puts the extra info (and just the extra info) into builder.
*/
virtual void serialize(BSONObjBuilder* builder) const = 0;
/**
* Returns the registered parser for a given code or nullptr if none is registered.
*/
static Parser* parserFor(ErrorCodes::Error);
/**
* Use the MONGO_INIT_REGISTER_ERROR_EXTRA_INFO(type) macro below rather than calling this
* directly.
*/
template <typename T>
static void registerType() {
MONGO_STATIC_ASSERT(std::is_base_of<ErrorExtraInfo, T>());
MONGO_STATIC_ASSERT(std::is_same<error_details::ErrorExtraInfoFor<T::code>, T>());
MONGO_STATIC_ASSERT(std::is_final<T>());
MONGO_STATIC_ASSERT(std::is_move_constructible<T>());
registerParser(T::code, T::parse);
}
/**
* Fails fatally if any error codes that should have parsers registered don't. An invariant in
* this function indicates that there isn't a MONGO_INIT_REGISTER_ERROR_EXTRA_INFO declaration
* for some error code, which requires an extra info.
*
* Call this during startup of any shipping executable to prevent failures at runtime.
*/
static void invariantHaveAllParsers();
private:
static void registerParser(ErrorCodes::Error code, Parser* parser);
};
/**
* Registers the parser for an ErrorExtraInfo subclass. This must be called at namespace scope in
* the same cpp file as the virtual methods for that type.
*
* You must separately #include "mongo/base/init.h" since including it here would create an include
* cycle.
*/
#define MONGO_INIT_REGISTER_ERROR_EXTRA_INFO(type) \
MONGO_INITIALIZER_GENERAL( \
RegisterErrorExtraInfoFor##type, MONGO_NO_PREREQUISITES, ("default")) \
(InitializerContext * context) { \
ErrorExtraInfo::registerType<type>(); \
return Status::OK(); \
}
/**
* This is an example ErrorExtraInfo subclass. It is used for testing the ErrorExtraInfoHandling.
*
* The default parser just throws a numeric code since this class should never be encountered in
* production. A normal parser is activated while an EnableParserForTesting object is in scope.
*/
class ErrorExtraInfoExample final : public ErrorExtraInfo {
public:
static constexpr auto code = ErrorCodes::ForTestingErrorExtraInfo;
void serialize(BSONObjBuilder*) const override;
static std::shared_ptr<const ErrorExtraInfo> parse(const BSONObj&);
// Everything else in this class is just for testing and shouldn't by copied by users.
struct EnableParserForTest {
EnableParserForTest() {
isParserEnabledForTest = true;
}
~EnableParserForTest() {
isParserEnabledForTest = false;
}
};
ErrorExtraInfoExample(int data) : data(data) {}
int data; // This uses the fieldname "data".
private:
static bool isParserEnabledForTest;
};
namespace nested::twice {
/**
* This is an example ErrorExtraInfo subclass. It is used for testing the ErrorExtraInfoHandling.
*
* It is meant to be a duplicate of ErrorExtraInfoExample, except that it is within a namespace
* (and so exercises a different codepath in the parser).
*/
class NestedErrorExtraInfoExample final : public ErrorExtraInfo {
public:
static constexpr auto code = ErrorCodes::ForTestingErrorExtraInfoWithExtraInfoInNamespace;
void serialize(BSONObjBuilder*) const override;
static std::shared_ptr<const ErrorExtraInfo> parse(const BSONObj&);
// Everything else in this class is just for testing and shouldn't by copied by users.
struct EnableParserForTest {
EnableParserForTest() {
isParserEnabledForTest = true;
}
~EnableParserForTest() {
isParserEnabledForTest = false;
}
};
NestedErrorExtraInfoExample(int data) : data(data) {}
int data; // This uses the fieldname "data".
private:
static bool isParserEnabledForTest;
};
} // namespace nested::twice
} // namespace mongo
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