ClickHouse/dbms/src/Functions/RapidJSONParser.h
2019-08-09 23:58:16 +03:00

214 lines
7.8 KiB
C++

#pragma once
#include "config_functions.h"
#if USE_RAPIDJSON
#include <common/StringRef.h>
#include <Common/Exception.h>
#include <Core/Types.h>
#include <rapidjson/document.h>
namespace DB
{
/// This class can be used as an argument for the template class FunctionJSON.
/// It provides ability to parse JSONs using rapidjson library.
struct RapidJSONParser
{
static constexpr bool need_preallocate = false;
void preallocate(size_t) {}
bool parse(const StringRef & json)
{
rapidjson::MemoryStream ms(json.data, json.size);
rapidjson::EncodedInputStream<rapidjson::UTF8<>, rapidjson::MemoryStream> is(ms);
document.ParseStream(is);
return !document.HasParseError() && (ms.Tell() == json.size);
}
struct Iterator
{
public:
Iterator() {}
Iterator(const rapidjson::Document & document_) : value(&document_) {}
Iterator(const Iterator & src)
: value(src.value)
, is_object_member(src.is_object_member)
, current_in_array(src.current_in_array)
, end_of_array(src.end_of_array) {}
Iterator & operator =(const Iterator & src)
{
value = src.value;
is_object_member = src.is_object_member;
current_in_array = src.current_in_array;
end_of_array = src.end_of_array;
return *this;
}
bool isInt64() const { return value->IsInt64(); }
bool isUInt64() const { return value->IsUint64(); }
bool isDouble() const { return value->IsDouble(); }
bool isBool() const { return value->IsBool(); }
bool isString() const { return value->IsString(); }
bool isArray() const { return value->IsArray(); }
bool isObject() const { return value->IsObject(); }
bool isNull() const { return value->IsNull(); }
Int64 getInt64() const { return value->GetInt64(); }
UInt64 getUInt64() const { return value->GetUint64(); }
double getDouble() const { return value->GetDouble(); }
bool getBool() const { return value->GetBool(); }
StringRef getString() const { return {value->GetString(), value->GetStringLength()}; }
size_t sizeOfArray() const { return value->Size(); }
bool arrayElementByIndex(size_t index)
{
if (index >= value->Size())
return false;
setRange(value->Begin() + index, value->End());
value = current_in_array++;
return true;
}
bool nextArrayElement()
{
if (current_in_array == end_of_array)
return false;
value = current_in_array++;
return true;
}
size_t sizeOfObject() const { return value->MemberCount(); }
bool objectMemberByIndex(size_t index)
{
if (index >= value->MemberCount())
return false;
setRange(value->MemberBegin() + index, value->MemberEnd());
value = &(current_in_object++)->value;
return true;
}
bool objectMemberByIndex(size_t index, StringRef & key)
{
if (index >= value->MemberCount())
return false;
setRange(value->MemberBegin() + index, value->MemberEnd());
key = getKeyImpl(current_in_object);
value = &(current_in_object++)->value;
return true;
}
bool objectMemberByName(const StringRef & name)
{
auto it = value->FindMember(name.data);
if (it == value->MemberEnd())
return false;
setRange(it, value->MemberEnd());
value = &(current_in_object++)->value;
return true;
}
bool nextObjectMember()
{
if (current_in_object == end_of_object)
return false;
value = &(current_in_object++)->value;
return true;
}
bool nextObjectMember(StringRef & key)
{
if (current_in_object == end_of_object)
return false;
key = getKeyImpl(current_in_object);
value = &(current_in_object++)->value;
return true;
}
bool isObjectMember() const { return is_object_member; }
StringRef getKey() const
{
return getKeyImpl(current_in_object - 1);
}
private:
void setRange(rapidjson::Value::ConstValueIterator current, rapidjson::Value::ConstValueIterator end)
{
current_in_array = &*current;
end_of_array = &*end;
is_object_member = false;
}
void setRange(rapidjson::Value::ConstMemberIterator current, rapidjson::Value::ConstMemberIterator end)
{
current_in_object = &*current;
end_of_object = &*end;
is_object_member = true;
}
static StringRef getKeyImpl(const rapidjson::GenericMember<rapidjson::UTF8<>, rapidjson::MemoryPoolAllocator<>> * member)
{
const auto & name = member->name;
return {name.GetString(), name.GetStringLength()};
}
const rapidjson::Value * value = nullptr;
bool is_object_member = false;
union
{
const rapidjson::GenericMember<rapidjson::UTF8<>, rapidjson::MemoryPoolAllocator<>> * current_in_object;
const rapidjson::Value * current_in_array;
};
union
{
const rapidjson::GenericMember<rapidjson::UTF8<>, rapidjson::MemoryPoolAllocator<>> * end_of_object;
const rapidjson::Value * end_of_array;
};
};
Iterator getRoot() { return Iterator{document}; }
static bool isInt64(const Iterator & it) { return it.isInt64(); }
static bool isUInt64(const Iterator & it) { return it.isUInt64(); }
static bool isDouble(const Iterator & it) { return it.isDouble(); }
static bool isBool(const Iterator & it) { return it.isBool(); }
static bool isString(const Iterator & it) { return it.isString(); }
static bool isArray(const Iterator & it) { return it.isArray(); }
static bool isObject(const Iterator & it) { return it.isObject(); }
static bool isNull(const Iterator & it) { return it.isNull(); }
static Int64 getInt64(const Iterator & it) { return it.getInt64(); }
static UInt64 getUInt64(const Iterator & it) { return it.getUInt64(); }
static double getDouble(const Iterator & it) { return it.getDouble(); }
static bool getBool(const Iterator & it) { return it.getBool(); }
static StringRef getString(const Iterator & it) { return it.getString(); }
static size_t sizeOfArray(const Iterator & it) { return it.sizeOfArray(); }
static bool firstArrayElement(Iterator & it) { return it.arrayElementByIndex(0); }
static bool arrayElementByIndex(Iterator & it, size_t index) { return it.arrayElementByIndex(index); }
static bool nextArrayElement(Iterator & it) { return it.nextArrayElement(); }
static size_t sizeOfObject(const Iterator & it) { return it.sizeOfObject(); }
static bool firstObjectMember(Iterator & it) { return it.objectMemberByIndex(0); }
static bool firstObjectMember(Iterator & it, StringRef & first_key) { return it.objectMemberByIndex(0, first_key); }
static bool objectMemberByIndex(Iterator & it, size_t index) { return it.objectMemberByIndex(index); }
static bool objectMemberByName(Iterator & it, const StringRef & name) { return it.objectMemberByName(name); }
static bool nextObjectMember(Iterator & it) { return it.nextObjectMember(); }
static bool nextObjectMember(Iterator & it, StringRef & next_key) { return it.nextObjectMember(next_key); }
static bool isObjectMember(const Iterator & it) { return it.isObjectMember(); }
static StringRef getKey(const Iterator & it) { return it.getKey(); }
private:
rapidjson::Document document;
};
}
#endif