Files
scylladb/query-result-set.hh
2015-07-02 13:25:46 +02:00

118 lines
3.6 KiB
C++

/*
* Copyright 2015 Cloudius Systems
*/
#pragma once
#include "core/shared_ptr.hh"
#include "query-request.hh"
#include "query-result.hh"
#include "schema.hh"
#include <experimental/optional>
#include <stdexcept>
#include <boost/any.hpp>
namespace query {
class no_such_column : public std::runtime_error {
public:
using runtime_error::runtime_error;
};
class null_column_value : public std::runtime_error {
public:
using runtime_error::runtime_error;
};
// Result set row is a set of cells that are associated with a row
// including regular column cells, partition keys, as well as static values.
class result_set_row {
schema_ptr _schema;
std::unordered_map<sstring, data_value> _cells;
public:
result_set_row(schema_ptr schema, std::unordered_map<sstring, data_value>&& cells)
: _schema{schema}
, _cells{std::move(cells)}
{ }
bool has(const sstring& column_name) const {
return _cells.count(column_name) > 0;
}
// Look up a deserialized row cell value by column name.
const data_value&
get_data_value(const sstring& column_name) const throw (no_such_column) {
auto it = _cells.find(column_name);
if (it == _cells.end()) {
throw no_such_column(column_name);
}
return it->second;
}
// Look up a deserialized row cell value by column name.
template<typename T>
std::experimental::optional<T>
get(const sstring& column_name) const throw (no_such_column) {
auto&& value = get_data_value(column_name).value();
if (value.empty()) {
return std::experimental::nullopt;
}
return std::experimental::optional<T>{boost::any_cast<T>(value)};
}
template<typename T>
T get_nonnull(const sstring& column_name) const throw (no_such_column, null_column_value) {
auto v = get<T>(column_name);
if (v) {
return *v;
}
throw null_column_value(column_name);
}
friend inline bool operator==(const result_set_row& x, const result_set_row& y);
friend inline bool operator!=(const result_set_row& x, const result_set_row& y);
friend std::ostream& operator<<(std::ostream& out, const result_set_row& row);
};
inline bool operator==(const result_set_row& x, const result_set_row& y) {
return x._schema == y._schema && x._cells == y._cells;
}
inline bool operator!=(const result_set_row& x, const result_set_row& y) {
return !(x == y);
}
// Result set is an in-memory representation of query results in
// deserialized format. To obtain a result set, use the result_set_builder
// class as a visitor to query_result::consume() function.
class result_set {
schema_ptr _schema;
std::vector<result_set_row> _rows;
public:
static result_set from_raw_result(schema_ptr, const partition_slice&, const result&);
result_set(schema_ptr s, const std::vector<result_set_row>& rows)
: _schema(std::move(s)), _rows{std::move(rows)}
{ }
bool empty() const {
return _rows.empty();
}
const result_set_row& row(size_t idx) const throw (std::out_of_range) {
if (idx >= _rows.size()) {
throw std::out_of_range("no such row in result set: " + std::to_string(idx));
}
return _rows[idx];
}
const std::vector<result_set_row>& rows() const {
return _rows;
}
const schema_ptr& schema() const {
return _schema;
}
friend inline bool operator==(const result_set& x, const result_set& y);
friend std::ostream& operator<<(std::ostream& out, const result_set& rs);
};
inline bool operator==(const result_set& x, const result_set& y) {
return x._rows == y._rows;
}
}