ClickHouse/dbms/src/Common/FieldVisitors.h

324 lines
15 KiB
C++

#pragma once
#include <Core/Field.h>
#include <Core/AccurateComparison.h>
#include <common/DateLUT.h>
#include <Common/demangle.h>
class SipHash;
namespace DB
{
namespace ErrorCodes
{
extern const int CANNOT_CONVERT_TYPE;
extern const int LOGICAL_ERROR;
}
/** StaticVisitor (and its descendants) - class with overloaded operator() for all types of fields.
* You could call visitor for field using function 'applyVisitor'.
* Also "binary visitor" is supported - its operator() takes two arguments.
*/
template <typename R = void>
struct StaticVisitor
{
using ResultType = R;
};
/// F is template parameter, to allow universal reference for field, that is useful for const and non-const values.
template <typename Visitor, typename F>
typename std::decay_t<Visitor>::ResultType applyVisitor(Visitor && visitor, F && field)
{
switch (field.getType())
{
case Field::Types::Null: return visitor(field.template get<Null>());
case Field::Types::UInt64: return visitor(field.template get<UInt64>());
case Field::Types::Int64: return visitor(field.template get<Int64>());
case Field::Types::Float64: return visitor(field.template get<Float64>());
case Field::Types::String: return visitor(field.template get<String>());
case Field::Types::Array: return visitor(field.template get<Array>());
case Field::Types::Tuple: return visitor(field.template get<Tuple>());
default:
throw Exception("Bad type of Field", ErrorCodes::BAD_TYPE_OF_FIELD);
}
}
template <typename Visitor, typename F1, typename F2>
static typename std::decay_t<Visitor>::ResultType applyBinaryVisitorImpl(Visitor && visitor, F1 && field1, F2 && field2)
{
switch (field2.getType())
{
case Field::Types::Null: return visitor(field1, field2.template get<Null>());
case Field::Types::UInt64: return visitor(field1, field2.template get<UInt64>());
case Field::Types::Int64: return visitor(field1, field2.template get<Int64>());
case Field::Types::Float64: return visitor(field1, field2.template get<Float64>());
case Field::Types::String: return visitor(field1, field2.template get<String>());
case Field::Types::Array: return visitor(field1, field2.template get<Array>());
case Field::Types::Tuple: return visitor(field1, field2.template get<Tuple>());
default:
throw Exception("Bad type of Field", ErrorCodes::BAD_TYPE_OF_FIELD);
}
}
template <typename Visitor, typename F1, typename F2>
typename std::decay_t<Visitor>::ResultType applyVisitor(Visitor && visitor, F1 && field1, F2 && field2)
{
switch (field1.getType())
{
case Field::Types::Null:
return applyBinaryVisitorImpl(
std::forward<Visitor>(visitor), field1.template get<Null>(), std::forward<F2>(field2));
case Field::Types::UInt64:
return applyBinaryVisitorImpl(
std::forward<Visitor>(visitor), field1.template get<UInt64>(), std::forward<F2>(field2));
case Field::Types::Int64:
return applyBinaryVisitorImpl(
std::forward<Visitor>(visitor), field1.template get<Int64>(), std::forward<F2>(field2));
case Field::Types::Float64:
return applyBinaryVisitorImpl(
std::forward<Visitor>(visitor), field1.template get<Float64>(), std::forward<F2>(field2));
case Field::Types::String:
return applyBinaryVisitorImpl(
std::forward<Visitor>(visitor), field1.template get<String>(), std::forward<F2>(field2));
case Field::Types::Array:
return applyBinaryVisitorImpl(
std::forward<Visitor>(visitor), field1.template get<Array>(), std::forward<F2>(field2));
case Field::Types::Tuple:
return applyBinaryVisitorImpl(
std::forward<Visitor>(visitor), field1.template get<Tuple>(), std::forward<F2>(field2));
default:
throw Exception("Bad type of Field", ErrorCodes::BAD_TYPE_OF_FIELD);
}
}
/** Prints Field as literal in SQL query */
class FieldVisitorToString : public StaticVisitor<String>
{
public:
String operator() (const Null & x) const;
String operator() (const UInt64 & x) const;
String operator() (const Int64 & x) const;
String operator() (const Float64 & x) const;
String operator() (const String & x) const;
String operator() (const Array & x) const;
String operator() (const Tuple & x) const;
};
/** Print readable and unique text dump of field type and value. */
class FieldVisitorDump : public StaticVisitor<String>
{
public:
String operator() (const Null & x) const;
String operator() (const UInt64 & x) const;
String operator() (const Int64 & x) const;
String operator() (const Float64 & x) const;
String operator() (const String & x) const;
String operator() (const Array & x) const;
String operator() (const Tuple & x) const;
};
/** Converts numberic value of any type to specified type. */
template <typename T>
class FieldVisitorConvertToNumber : public StaticVisitor<T>
{
public:
T operator() (const Null &) const
{
throw Exception("Cannot convert NULL to " + demangle(typeid(T).name()), ErrorCodes::CANNOT_CONVERT_TYPE);
}
T operator() (const String &) const
{
throw Exception("Cannot convert String to " + demangle(typeid(T).name()), ErrorCodes::CANNOT_CONVERT_TYPE);
}
T operator() (const Array &) const
{
throw Exception("Cannot convert Array to " + demangle(typeid(T).name()), ErrorCodes::CANNOT_CONVERT_TYPE);
}
T operator() (const Tuple &) const
{
throw Exception("Cannot convert Tuple to " + demangle(typeid(T).name()), ErrorCodes::CANNOT_CONVERT_TYPE);
}
T operator() (const UInt64 & x) const { return x; }
T operator() (const Int64 & x) const { return x; }
T operator() (const Float64 & x) const { return x; }
};
/** Updates SipHash by type and value of Field */
class FieldVisitorHash : public StaticVisitor<>
{
private:
SipHash & hash;
public:
FieldVisitorHash(SipHash & hash);
void operator() (const Null & x) const;
void operator() (const UInt64 & x) const;
void operator() (const Int64 & x) const;
void operator() (const Float64 & x) const;
void operator() (const String & x) const;
void operator() (const Array & x) const;
};
/** More precise comparison, used for index.
* Differs from Field::operator< and Field::operator== in that it also compares values of different types.
* Comparison rules are same as in FunctionsComparison (to be consistent with expression evaluation in query).
*/
class FieldVisitorAccurateEquals : public StaticVisitor<bool>
{
public:
bool operator() (const Null &, const Null &) const { return true; }
bool operator() (const Null &, const UInt64 &) const { return false; }
bool operator() (const Null &, const Int64 &) const { return false; }
bool operator() (const Null &, const Float64 &) const { return false; }
bool operator() (const Null &, const String &) const { return false; }
bool operator() (const Null &, const Array &) const { return false; }
bool operator() (const Null &, const Tuple &) const { return false; }
bool operator() (const UInt64 &, const Null &) const { return false; }
bool operator() (const UInt64 & l, const UInt64 & r) const { return l == r; }
bool operator() (const UInt64 & l, const Int64 & r) const { return accurate::equalsOp(l, r); }
bool operator() (const UInt64 & l, const Float64 & r) const { return accurate::equalsOp(l, r); }
bool operator() (const UInt64 &, const String &) const { return false; }
bool operator() (const UInt64 &, const Array &) const { return false; }
bool operator() (const UInt64 &, const Tuple &) const { return false; }
bool operator() (const Int64 &, const Null &) const { return false; }
bool operator() (const Int64 & l, const UInt64 & r) const { return accurate::equalsOp(l, r); }
bool operator() (const Int64 & l, const Int64 & r) const { return l == r; }
bool operator() (const Int64 & l, const Float64 & r) const { return accurate::equalsOp(l, r); }
bool operator() (const Int64 &, const String &) const { return false; }
bool operator() (const Int64 &, const Array &) const { return false; }
bool operator() (const Int64 &, const Tuple &) const { return false; }
bool operator() (const Float64 &, const Null &) const { return false; }
bool operator() (const Float64 & l, const UInt64 & r) const { return accurate::equalsOp(l, r); }
bool operator() (const Float64 & l, const Int64 & r) const { return accurate::equalsOp(l, r); }
bool operator() (const Float64 & l, const Float64 & r) const { return l == r; }
bool operator() (const Float64 &, const String &) const { return false; }
bool operator() (const Float64 &, const Array &) const { return false; }
bool operator() (const Float64 &, const Tuple &) const { return false; }
bool operator() (const String &, const Null &) const { return false; }
bool operator() (const String &, const UInt64 &) const { return false; }
bool operator() (const String &, const Int64 &) const { return false; }
bool operator() (const String &, const Float64 &) const { return false; }
bool operator() (const String & l, const String & r) const { return l == r; }
bool operator() (const String &, const Array &) const { return false; }
bool operator() (const String &, const Tuple &) const { return false; }
bool operator() (const Array &, const Null &) const { return false; }
bool operator() (const Array &, const UInt64 &) const { return false; }
bool operator() (const Array &, const Int64 &) const { return false; }
bool operator() (const Array &, const Float64 &) const { return false; }
bool operator() (const Array &, const String &) const { return false; }
bool operator() (const Array & l, const Array & r) const { return l == r; }
bool operator() (const Array &, const Tuple &) const { return false; }
bool operator() (const Tuple &, const Null &) const { return false; }
bool operator() (const Tuple &, const UInt64 &) const { return false; }
bool operator() (const Tuple &, const Int64 &) const { return false; }
bool operator() (const Tuple &, const Float64 &) const { return false; }
bool operator() (const Tuple &, const String &) const { return false; }
bool operator() (const Tuple &, const Array &) const { return false; }
bool operator() (const Tuple & l, const Tuple & r) const { return l == r; }
};
class FieldVisitorAccurateLess : public StaticVisitor<bool>
{
public:
bool operator() (const Null &, const Null &) const { return false; }
bool operator() (const Null &, const UInt64 &) const { return true; }
bool operator() (const Null &, const Int64 &) const { return true; }
bool operator() (const Null &, const Float64 &) const { return true; }
bool operator() (const Null &, const String &) const { return true; }
bool operator() (const Null &, const Array &) const { return true; }
bool operator() (const Null &, const Tuple &) const { return true; }
bool operator() (const UInt64 &, const Null &) const { return false; }
bool operator() (const UInt64 & l, const UInt64 & r) const { return l < r; }
bool operator() (const UInt64 & l, const Int64 & r) const { return accurate::lessOp(l, r); }
bool operator() (const UInt64 & l, const Float64 & r) const { return accurate::lessOp(l, r); }
bool operator() (const UInt64 &, const String &) const { return true; }
bool operator() (const UInt64 &, const Array &) const { return true; }
bool operator() (const UInt64 &, const Tuple &) const { return true; }
bool operator() (const Int64 &, const Null &) const { return false; }
bool operator() (const Int64 & l, const UInt64 & r) const { return accurate::lessOp(l, r); }
bool operator() (const Int64 & l, const Int64 & r) const { return l < r; }
bool operator() (const Int64 & l, const Float64 & r) const { return accurate::lessOp(l, r); }
bool operator() (const Int64 &, const String &) const { return true; }
bool operator() (const Int64 &, const Array &) const { return true; }
bool operator() (const Int64 &, const Tuple &) const { return true; }
bool operator() (const Float64 &, const Null &) const { return false; }
bool operator() (const Float64 & l, const UInt64 & r) const { return accurate::lessOp(l, r); }
bool operator() (const Float64 & l, const Int64 & r) const { return accurate::lessOp(l, r); }
bool operator() (const Float64 & l, const Float64 & r) const { return l < r; }
bool operator() (const Float64 &, const String &) const { return true; }
bool operator() (const Float64 &, const Array &) const { return true; }
bool operator() (const Float64 &, const Tuple &) const { return true; }
bool operator() (const String &, const Null &) const { return false; }
bool operator() (const String &, const UInt64 &) const { return false; }
bool operator() (const String &, const Int64 &) const { return false; }
bool operator() (const String &, const Float64 &) const { return false; }
bool operator() (const String & l, const String & r) const { return l < r; }
bool operator() (const String &, const Array &) const { return true; }
bool operator() (const String &, const Tuple &) const { return true; }
bool operator() (const Array &, const Null &) const { return false; }
bool operator() (const Array &, const UInt64 &) const { return false; }
bool operator() (const Array &, const Int64 &) const { return false; }
bool operator() (const Array &, const Float64 &) const { return false; }
bool operator() (const Array &, const String &) const { return false; }
bool operator() (const Array & l, const Array & r) const { return l < r; }
bool operator() (const Array &, const Tuple &) const { return false; }
bool operator() (const Tuple &, const Null &) const { return false; }
bool operator() (const Tuple &, const UInt64 &) const { return false; }
bool operator() (const Tuple &, const Int64 &) const { return false; }
bool operator() (const Tuple &, const Float64 &) const { return false; }
bool operator() (const Tuple &, const String &) const { return false; }
bool operator() (const Tuple &, const Array &) const { return false; }
bool operator() (const Tuple & l, const Tuple & r) const { return l < r; }
};
/** Implements `+=` operation.
* Returns false if the result is zero.
*/
class FieldVisitorSum : public StaticVisitor<bool>
{
private:
const Field & rhs;
public:
explicit FieldVisitorSum(const Field & rhs_) : rhs(rhs_) {}
bool operator() (UInt64 & x) const { x += get<UInt64>(rhs); return x != 0; }
bool operator() (Int64 & x) const { x += get<Int64>(rhs); return x != 0; }
bool operator() (Float64 & x) const { x += get<Float64>(rhs); return x != 0; }
bool operator() (Null &) const { throw Exception("Cannot sum Nulls", ErrorCodes::LOGICAL_ERROR); }
bool operator() (String &) const { throw Exception("Cannot sum Strings", ErrorCodes::LOGICAL_ERROR); }
bool operator() (Array &) const { throw Exception("Cannot sum Arrays", ErrorCodes::LOGICAL_ERROR); }
};
}