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rocksdb/include/utilities/json_document.h

173 lines
4.7 KiB

// Copyright (c) 2013, Facebook, Inc. All rights reserved.
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree. An additional grant
// of patent rights can be found in the PATENTS file in the same directory.
#pragma once
#ifndef ROCKSDB_LITE
#include <string>
#include <map>
#include <unordered_map>
#include <vector>
#include "rocksdb/slice.h"
// We use JSONDocument for DocumentDB API
// Implementation inspired by folly::dynamic and rapidjson
namespace rocksdb {
// NOTE: none of this is thread-safe
class JSONDocument {
public:
// return nullptr on parse failure
static JSONDocument* ParseJSON(const char* json);
enum Type {
kNull,
kArray,
kBool,
kDouble,
kInt64,
kObject,
kString,
};
JSONDocument(); // null
/* implicit */ JSONDocument(bool b);
/* implicit */ JSONDocument(double d);
/* implicit */ JSONDocument(int64_t i);
/* implicit */ JSONDocument(const std::string& s);
/* implicit */ JSONDocument(const char* s);
// constructs JSONDocument of specific type with default value
explicit JSONDocument(Type type);
// copy constructor
JSONDocument(const JSONDocument& json_document);
~JSONDocument();
Type type() const;
// REQUIRES: IsObject()
bool Contains(const std::string& key) const;
// Returns nullptr if !Contains()
// don't delete the returned pointer
// REQUIRES: IsObject()
const JSONDocument* Get(const std::string& key) const;
// REQUIRES: IsObject()
JSONDocument& operator[](const std::string& key);
// REQUIRES: IsObject()
const JSONDocument& operator[](const std::string& key) const;
// returns `this`, so you can chain operations.
// Copies value
// REQUIRES: IsObject()
JSONDocument* Set(const std::string& key, const JSONDocument& value);
// REQUIRES: IsArray() == true || IsObject() == true
size_t Count() const;
// REQUIRES: IsArray()
const JSONDocument* GetFromArray(size_t i) const;
// REQUIRES: IsArray()
JSONDocument& operator[](size_t i);
// REQUIRES: IsArray()
const JSONDocument& operator[](size_t i) const;
// returns `this`, so you can chain operations.
// Copies the value
// REQUIRES: IsArray() && i < Count()
JSONDocument* SetInArray(size_t i, const JSONDocument& value);
// REQUIRES: IsArray()
JSONDocument* PushBack(const JSONDocument& value);
bool IsNull() const;
bool IsArray() const;
bool IsBool() const;
bool IsDouble() const;
bool IsInt64() const;
bool IsObject() const;
bool IsString() const;
// REQUIRES: IsBool() == true
bool GetBool() const;
// REQUIRES: IsDouble() == true
double GetDouble() const;
// REQUIRES: IsInt64() == true
int64_t GetInt64() const;
// REQUIRES: IsString() == true
const std::string& GetString() const;
bool operator==(const JSONDocument& rhs) const;
private:
class ItemsIteratorGenerator;
public:
// REQUIRES: IsObject()
ItemsIteratorGenerator Items() const;
// appends serialized object to dst
void Serialize(std::string* dst) const;
// returns nullptr if Slice doesn't represent valid serialized JSONDocument
static JSONDocument* Deserialize(const Slice& src);
private:
void SerializeInternal(std::string* dst, bool type_prefix) const;
// returns false if Slice doesn't represent valid serialized JSONDocument.
// Otherwise, true
bool DeserializeInternal(Slice* input);
typedef std::vector<JSONDocument*> Array;
typedef std::unordered_map<std::string, JSONDocument*> Object;
// iteration on objects
class const_item_iterator {
public:
typedef Object::const_iterator It;
typedef Object::value_type value_type;
/* implicit */ const_item_iterator(It it) : it_(it) {}
It& operator++() { return ++it_; }
bool operator!=(const const_item_iterator& other) {
return it_ != other.it_;
}
value_type operator*() { return *it_; }
private:
It it_;
};
class ItemsIteratorGenerator {
public:
/* implicit */ ItemsIteratorGenerator(const Object& object)
: object_(object) {}
const_item_iterator begin() { return object_.begin(); }
const_item_iterator end() { return object_.end(); }
private:
const Object& object_;
};
union Data {
Data() : n(nullptr) {}
~Data() {}
void* n;
Array a;
bool b;
double d;
int64_t i;
std::string s;
Object o;
} data_;
const Type type_;
// Our serialization format's first byte specifies the encoding version. That
// way, we can easily change our format while providing backwards
// compatibility. This constant specifies the current version of the
// serialization format
static const char kSerializationFormatVersion;
};
} // namespace rocksdb
#endif // ROCKSDB_LITE