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/*
* 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 _THRIFT_TREFLECTIONLOCAL_H_
#define _THRIFT_TREFLECTIONLOCAL_H_ 1
#include <stdint.h>
#include <cstring>
#include <protocol/TProtocol.h>
/**
* Local Reflection is a blanket term referring to the the structure
* and generation of this particular representation of Thrift types.
* (It is called local because it cannot be serialized by Thrift).
*
*/
namespace apache { namespace thrift { namespace reflection { namespace local {
using apache::thrift::protocol::TType;
// We include this many bytes of the structure's fingerprint when serializing
// a top-level structure. Long enough to make collisions unlikely, short
// enough to not significantly affect the amount of memory used.
const int FP_PREFIX_LEN = 4;
struct FieldMeta {
int16_t tag;
bool is_optional;
};
struct TypeSpec {
TType ttype;
uint8_t fp_prefix[FP_PREFIX_LEN];
// Use an anonymous union here so we can fit two TypeSpecs in one cache line.
union {
struct {
// Use parallel arrays here for denser packing (of the arrays).
FieldMeta* metas;
TypeSpec** specs;
} tstruct;
struct {
TypeSpec *subtype1;
TypeSpec *subtype2;
} tcontainer;
};
// Static initialization of unions isn't really possible,
// so take the plunge and use constructors.
// Hopefully they'll be evaluated at compile time.
TypeSpec(TType ttype) : ttype(ttype) {
std::memset(fp_prefix, 0, FP_PREFIX_LEN);
}
TypeSpec(TType ttype,
const uint8_t* fingerprint,
FieldMeta* metas,
TypeSpec** specs) :
ttype(ttype)
{
std::memcpy(fp_prefix, fingerprint, FP_PREFIX_LEN);
tstruct.metas = metas;
tstruct.specs = specs;
}
TypeSpec(TType ttype, TypeSpec* subtype1, TypeSpec* subtype2) :
ttype(ttype)
{
std::memset(fp_prefix, 0, FP_PREFIX_LEN);
tcontainer.subtype1 = subtype1;
tcontainer.subtype2 = subtype2;
}
};
}}}} // apache::thrift::reflection::local
#endif // #ifndef _THRIFT_TREFLECTIONLOCAL_H_
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