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438 lines
12 KiB
C++
438 lines
12 KiB
C++
#pragma once
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#include <vector>
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#include <type_traits>
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#include <functional>
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#include <boost/static_assert.hpp>
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#include <DB/Common/Exception.h>
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#include <DB/Core/ErrorCodes.h>
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#include <DB/Core/Types.h>
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namespace DB
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{
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class Field;
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typedef std::vector<Field> Array; /// Значение типа "массив"
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using Poco::SharedPtr;
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/** 32 хватает с запасом (достаточно 28), но выбрано круглое число,
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* чтобы арифметика при использовании массивов из Field была проще (не содержала умножения).
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*/
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#define DBMS_TOTAL_FIELD_SIZE 32
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/** Discriminated union из нескольких типов.
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* Сделан для замены boost::variant:
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* является не обобщённым,
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* зато несколько более эффективным, и более простым.
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*
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* Используется для представления единичного значения одного из нескольких типов в оперативке.
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* Внимание! Предпочтительно вместо единичных значений хранить кусочки столбцов. См. Column.h
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*/
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class __attribute__((aligned(DBMS_TOTAL_FIELD_SIZE))) Field
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{
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public:
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struct Types
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{
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/// Идентификатор типа.
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enum Which
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{
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Null = 0,
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UInt64 = 1,
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Int64 = 2,
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Float64 = 3,
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/// не POD типы. Для них предполагается relocatable.
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String = 16,
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Array = 17,
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};
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static const int MIN_NON_POD = 16;
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static const char * toString(Which which)
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{
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switch (which)
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{
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case Null: return "Null";
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case UInt64: return "UInt64";
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case Int64: return "Int64";
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case Float64: return "Float64";
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case String: return "String";
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case Array: return "Array";
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default:
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throw Exception("Bad type of Field", ErrorCodes::BAD_TYPE_OF_FIELD);
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}
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}
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};
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/// Позволяет получить идентификатор для типа или наоборот.
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template <typename T> struct TypeToEnum;
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template <Types::Which which> struct EnumToType;
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Field()
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: which(Types::Null)
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{
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}
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/** Не смотря на наличие шаблонного конструктора, этот конструктор всё-равно нужен,
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* так как при его отсутствии, компилятор всё-равно сгенерирует конструктор по-умолчанию.
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*/
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Field(const Field & rhs)
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{
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create(rhs);
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}
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Field & operator= (const Field & rhs)
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{
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destroy();
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create(rhs);
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return *this;
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}
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template <typename T>
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Field(const T & rhs)
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{
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create(rhs);
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}
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/// Создать строку inplace.
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Field(const char * data, size_t size)
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{
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create(data, size);
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}
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Field(const unsigned char * data, size_t size)
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{
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create(data, size);
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}
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void assignString(const char * data, size_t size)
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{
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destroy();
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create(data, size);
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}
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void assignString(const unsigned char * data, size_t size)
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{
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destroy();
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create(data, size);
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}
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template <typename T>
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Field & operator= (const T & rhs)
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{
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destroy();
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create(rhs);
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return *this;
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}
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~Field()
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{
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destroy();
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}
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Types::Which getType() const { return which; }
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const char * getTypeName() const { return Types::toString(which); }
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bool isNull() const { return which == Types::Null; }
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template <typename T> T & get()
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{
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typedef typename std::remove_reference<T>::type TWithoutRef;
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TWithoutRef * __attribute__((__may_alias__)) ptr = reinterpret_cast<TWithoutRef*>(storage);
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return *ptr;
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};
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template <typename T> const T & get() const
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{
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typedef typename std::remove_reference<T>::type TWithoutRef;
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const TWithoutRef * __attribute__((__may_alias__)) ptr = reinterpret_cast<const TWithoutRef*>(storage);
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return *ptr;
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};
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template <typename T> T & safeGet()
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{
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const Types::Which requested = TypeToEnum<typename std::remove_cv<typename std::remove_reference<T>::type>::type>::value;
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if (which != requested)
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throw Exception("Bad get: has " + std::string(getTypeName()) + ", requested " + std::string(Types::toString(requested)), ErrorCodes::BAD_GET);
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return get<T>();
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}
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template <typename T> const T & safeGet() const
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{
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const Types::Which requested = TypeToEnum<typename std::remove_cv<typename std::remove_reference<T>::type>::type>::value;
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if (which != requested)
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throw Exception("Bad get: has " + std::string(getTypeName()) + ", requested " + std::string(Types::toString(requested)), ErrorCodes::BAD_GET);
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return get<T>();
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}
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bool operator< (const Field & rhs) const
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{
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if (which < rhs.which)
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return true;
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if (which > rhs.which)
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return false;
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switch (which)
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{
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case Types::Null: return false;
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case Types::UInt64: return get<UInt64>() < rhs.get<UInt64>();
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case Types::Int64: return get<Int64>() < rhs.get<Int64>();
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case Types::Float64: return get<Float64>() < rhs.get<Float64>();
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case Types::String: return get<String>() < rhs.get<String>();
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case Types::Array: return get<Array>() < rhs.get<Array>();
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default:
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throw Exception("Bad type of Field", ErrorCodes::BAD_TYPE_OF_FIELD);
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}
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}
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bool operator> (const Field & rhs) const
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{
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return rhs < *this;
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}
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bool operator<= (const Field & rhs) const
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{
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if (which < rhs.which)
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return true;
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if (which > rhs.which)
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return false;
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switch (which)
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{
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case Types::Null: return true;
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case Types::UInt64: return get<UInt64>() <= rhs.get<UInt64>();
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case Types::Int64: return get<Int64>() <= rhs.get<Int64>();
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case Types::Float64: return get<Float64>() <= rhs.get<Float64>();
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case Types::String: return get<String>() <= rhs.get<String>();
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case Types::Array: return get<Array>() <= rhs.get<Array>();
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default:
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throw Exception("Bad type of Field", ErrorCodes::BAD_TYPE_OF_FIELD);
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}
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}
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bool operator>= (const Field & rhs) const
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{
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return rhs <= *this;
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}
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bool operator== (const Field & rhs) const
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{
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if (which != rhs.which)
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return false;
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switch (which)
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{
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case Types::Null: return true;
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case Types::UInt64:
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case Types::Int64:
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case Types::Float64: return get<UInt64>() == rhs.get<UInt64>();
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case Types::String: return get<String>() == rhs.get<String>();
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case Types::Array: return get<Array>() == rhs.get<Array>();
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default:
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throw Exception("Bad type of Field", ErrorCodes::BAD_TYPE_OF_FIELD);
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}
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}
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bool operator!= (const Field & rhs) const
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{
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return !(*this == rhs);
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}
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private:
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/// Хватает с запасом
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static const size_t storage_size = DBMS_TOTAL_FIELD_SIZE - sizeof(Types::Which);
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BOOST_STATIC_ASSERT(storage_size >= sizeof(Null));
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BOOST_STATIC_ASSERT(storage_size >= sizeof(UInt64));
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BOOST_STATIC_ASSERT(storage_size >= sizeof(Int64));
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BOOST_STATIC_ASSERT(storage_size >= sizeof(Float64));
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BOOST_STATIC_ASSERT(storage_size >= sizeof(String));
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BOOST_STATIC_ASSERT(storage_size >= sizeof(Array));
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char storage[storage_size] __attribute__((aligned(8)));
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Types::Which which;
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template <typename T>
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void create(const T & x)
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{
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which = TypeToEnum<T>::value;
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T * __attribute__((__may_alias__)) ptr = reinterpret_cast<T*>(storage);
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new (ptr) T(x);
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}
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void create(const Null & x)
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{
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which = Types::Null;
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}
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void create(const Field & x)
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{
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switch (x.which)
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{
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case Types::Null: create(Null()); break;
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case Types::UInt64: create(x.get<UInt64>()); break;
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case Types::Int64: create(x.get<Int64>()); break;
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case Types::Float64: create(x.get<Float64>()); break;
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case Types::String: create(x.get<String>()); break;
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case Types::Array: create(x.get<Array>()); break;
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}
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}
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void create(const char * data, size_t size)
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{
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which = Types::String;
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String * __attribute__((__may_alias__)) ptr = reinterpret_cast<String*>(storage);
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new (ptr) String(data, size);
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}
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void create(const unsigned char * data, size_t size)
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{
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create(reinterpret_cast<const char *>(data), size);
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}
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__attribute__((__always_inline__)) void destroy()
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{
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if (which < Types::MIN_NON_POD)
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return;
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switch (which)
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{
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case Types::String:
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destroy<String>();
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break;
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case Types::Array:
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destroy<Array>();
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break;
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default:
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break;
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}
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}
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template <typename T>
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void destroy()
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{
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T * __attribute__((__may_alias__)) ptr = reinterpret_cast<T*>(storage);
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ptr->~T();
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}
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};
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#undef DBMS_TOTAL_FIELD_SIZE
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template <> struct Field::TypeToEnum<Null> { static const Types::Which value = Types::Null; };
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template <> struct Field::TypeToEnum<UInt64> { static const Types::Which value = Types::UInt64; };
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template <> struct Field::TypeToEnum<Int64> { static const Types::Which value = Types::Int64; };
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template <> struct Field::TypeToEnum<Float64> { static const Types::Which value = Types::Float64; };
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template <> struct Field::TypeToEnum<String> { static const Types::Which value = Types::String; };
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template <> struct Field::TypeToEnum<Array> { static const Types::Which value = Types::Array; };
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template <> struct Field::EnumToType<Field::Types::Null> { typedef Null Type; };
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template <> struct Field::EnumToType<Field::Types::UInt64> { typedef UInt64 Type; };
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template <> struct Field::EnumToType<Field::Types::Int64> { typedef Int64 Type; };
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template <> struct Field::EnumToType<Field::Types::Float64> { typedef Float64 Type; };
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template <> struct Field::EnumToType<Field::Types::String> { typedef String Type; };
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template <> struct Field::EnumToType<Field::Types::Array> { typedef Array Type; };
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template <typename T>
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T get(const Field & field)
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{
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return field.template get<T>();
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}
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template <typename T>
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T get(Field & field)
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{
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return field.template get<T>();
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}
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template <typename T>
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T safeGet(const Field & field)
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{
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return field.template safeGet<T>();
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}
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template <typename T>
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T safeGet(Field & field)
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{
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return field.template safeGet<T>();
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}
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template <> struct TypeName<Array> { static std::string get() { return "Array"; } };
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template <typename T> struct NearestFieldType;
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template <> struct NearestFieldType<UInt8> { typedef UInt64 Type; };
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template <> struct NearestFieldType<UInt16> { typedef UInt64 Type; };
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template <> struct NearestFieldType<UInt32> { typedef UInt64 Type; };
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template <> struct NearestFieldType<UInt64> { typedef UInt64 Type; };
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template <> struct NearestFieldType<Int8> { typedef Int64 Type; };
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template <> struct NearestFieldType<Int16> { typedef Int64 Type; };
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template <> struct NearestFieldType<Int32> { typedef Int64 Type; };
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template <> struct NearestFieldType<Int64> { typedef Int64 Type; };
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template <> struct NearestFieldType<Float32> { typedef Float64 Type; };
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template <> struct NearestFieldType<Float64> { typedef Float64 Type; };
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template <> struct NearestFieldType<String> { typedef String Type; };
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template <> struct NearestFieldType<Array> { typedef Array Type; };
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template <> struct NearestFieldType<bool> { typedef UInt64 Type; };
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template <typename T>
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typename NearestFieldType<T>::Type nearestFieldType(const T & x)
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{
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return typename NearestFieldType<T>::Type(x);
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}
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}
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/// Заглушки, чтобы DBObject-ы с полем типа Array компилировались.
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#include <mysqlxx/Manip.h>
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namespace mysqlxx
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{
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std::ostream & operator<< (mysqlxx::EscapeManipResult res, const DB::Array & value);
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std::ostream & operator<< (mysqlxx::QuoteManipResult res, const DB::Array & value);
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std::istream & operator>> (mysqlxx::UnEscapeManipResult res, DB::Array & value);
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std::istream & operator>> (mysqlxx::UnQuoteManipResult res, DB::Array & value);
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}
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namespace DB
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{
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class ReadBuffer;
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class WriteBuffer;
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/// Предполагается что у всех элементов массива одинаковый тип.
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void readBinary(Array & x, ReadBuffer & buf);
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inline void readText(Array & x, ReadBuffer & buf) { throw Exception("Cannot read Array.", ErrorCodes::NOT_IMPLEMENTED); }
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inline void readQuoted(Array & x, ReadBuffer & buf) { throw Exception("Cannot read Array.", ErrorCodes::NOT_IMPLEMENTED); }
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/// Предполагается что у всех элементов массива одинаковый тип.
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void writeBinary(const Array & x, WriteBuffer & buf);
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void writeText(const Array & x, WriteBuffer & buf);
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inline void writeQuoted(const Array & x, WriteBuffer & buf) { throw Exception("Cannot write Array quoted.", ErrorCodes::NOT_IMPLEMENTED); }
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}
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