src/brpc/reloadable_flags.h

// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you 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
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.


#ifndef BRPC_RELOADABLE_FLAGS_H
#define BRPC_RELOADABLE_FLAGS_H

// To brpc developers: This is a header included by user, don't depend
// on internal structures, use opaque pointers instead.

#include <stdint.h>

// Register an always-true valiator to a gflag so that the gflag is treated as
// reloadable by brpc. If a validator exists, abort the program.
// You should call this macro within global scope. for example:
//
//   DEFINE_int32(foo, 0, "blah blah");
//   BRPC_VALIDATE_GFLAG(foo, brpc::PassValidate);
//
// This macro does not work for string-flags because they're thread-unsafe to
// modify directly. To emphasize this, you have to write the validator by
// yourself and use GFLAGS_NS::GetCommandLineOption() to acess the flag.
#define BRPC_VALIDATE_GFLAG(flag, validate_fn)                     \
    namespace brpc_flags {}                                        \
    const int register_FLAGS_ ## flag ## _dummy                    \
                 __attribute__((__unused__)) =                     \
        ::brpc::RegisterFlagValidatorOrDie(                        \
            &FLAGS_##flag, (validate_fn))


namespace brpc {

extern bool PassValidate(const char*, bool);
extern bool PassValidate(const char*, int32_t);
extern bool PassValidate(const char*, uint32_t);
extern bool PassValidate(const char*, int64_t);
extern bool PassValidate(const char*, uint64_t);
extern bool PassValidate(const char*, double);

extern bool PositiveInteger(const char*, int32_t);
extern bool PositiveInteger(const char*, uint32_t);
extern bool PositiveInteger(const char*, int64_t);
extern bool PositiveInteger(const char*, uint64_t);

extern bool NonNegativeInteger(const char*, int32_t);
extern bool NonNegativeInteger(const char*, int64_t);

extern bool RegisterFlagValidatorOrDie(const bool* flag,
                                  bool (*validate_fn)(const char*, bool));
extern bool RegisterFlagValidatorOrDie(const int32_t* flag,
                                  bool (*validate_fn)(const char*, int32_t));
extern bool RegisterFlagValidatorOrDie(const uint32_t* flag,
                                  bool (*validate_fn)(const char*, uint32_t));
extern bool RegisterFlagValidatorOrDie(const int64_t* flag,
                                  bool (*validate_fn)(const char*, int64_t));
extern bool RegisterFlagValidatorOrDie(const uint64_t* flag,
                                  bool (*validate_fn)(const char*, uint64_t));
extern bool RegisterFlagValidatorOrDie(const double* flag,
                                  bool (*validate_fn)(const char*, double));
} // namespace brpc


#endif  // BRPC_RELOADABLE_FLAGS_H