13#ifndef PQXX_H_STREAM_TO
14#define PQXX_H_STREAM_TO
16#if !defined(PQXX_HEADER_PRE)
17# error "Include libpqxx headers as <pqxx/header>, not <pqxx/header.hxx>."
20#include "pqxx/separated_list.hxx"
21#include "pqxx/transaction_base.hxx"
80class PQXX_LIBEXPORT stream_to : transaction_focus
104 static stream_to raw_table(
105 transaction_base &tx, std::string_view path, std::string_view columns =
"")
107 return {tx, path, columns};
120 static stream_to table(
121 transaction_base &tx, table_path path,
122 std::initializer_list<std::string_view> columns = {})
124 auto const &conn{tx.conn()};
125 return raw_table(tx, conn.quote_table(path), conn.quote_columns(columns));
128#if defined(PQXX_HAVE_CONCEPTS)
137 template<PQXX_CHAR_STRINGS_ARG COLUMNS>
139 table(transaction_base &tx, table_path path, COLUMNS
const &columns)
141 auto const &conn{tx.conn()};
142 return stream_to::raw_table(
143 tx, conn.quote_table(path), tx.conn().quote_columns(columns));
154 template<PQXX_CHAR_STRINGS_ARG COLUMNS>
156 table(transaction_base &tx, std::string_view path, COLUMNS
const &columns)
158 return stream_to::raw_table(tx, path, tx.conn().quote_columns(columns));
162 explicit stream_to(stream_to &&other) :
165 transaction_focus{std::move(other)},
166 m_finished{other.m_finished},
167 m_buffer{std::move(other.m_buffer)},
168 m_field_buf{std::move(other.m_field_buf)},
169 m_finder{other.m_finder}
171 other.m_finished =
true;
173 ~stream_to() noexcept;
176 [[nodiscard]] constexpr operator
bool() const noexcept
178 return not m_finished;
181 [[nodiscard]]
constexpr bool operator!() const noexcept
205 template<
typename Row> stream_to &operator<<(Row
const &row)
216 stream_to &operator<<(stream_from &);
225 template<
typename Row>
void write_row(Row
const &row)
235 template<
typename... Ts>
void write_values(Ts
const &...fields)
237 fill_buffer(fields...);
251 [[deprecated(
"Use table() or raw_table() factory.")]] stream_to(
252 transaction_base &tx, std::string_view table_name) :
253 stream_to{tx, table_name,
""sv}
259 template<
typename Columns>
260 [[deprecated(
"Use table() or raw_table() factory.")]] stream_to(
261 transaction_base &, std::string_view table_name, Columns
const &columns);
266 template<
typename Iter>
267 [[deprecated(
"Use table() or raw_table() factory.")]] stream_to(
268 transaction_base &, std::string_view table_name, Iter columns_begin,
274 transaction_base &tx, std::string_view path, std::string_view columns);
276 bool m_finished =
false;
279 std::string m_buffer;
282 std::string m_field_buf;
285 internal::char_finder_func *m_finder;
288 void write_raw_line(std::string_view);
296 static constexpr std::string_view null_field{
"\\N\t"};
300 static std::enable_if_t<nullness<T>::always_null, std::size_t>
301 estimate_buffer(T
const &)
303 return std::size(null_field);
311 static std::enable_if_t<not nullness<T>::always_null, std::size_t>
312 estimate_buffer(T
const &field)
318 void escape_field_to_buffer(std::string_view data);
327 template<
typename Field>
328 std::enable_if_t<not nullness<Field>::always_null>
329 append_to_buffer(Field
const &f)
337 m_buffer.append(null_field);
343 using traits = string_traits<Field>;
344 auto const budget{estimate_buffer(f)};
345 auto const offset{std::size(m_buffer)};
347 if constexpr (std::is_arithmetic_v<Field>)
355 auto const total{offset + budget};
356 m_buffer.resize(total);
357 auto const data{m_buffer.data()};
358 char *
const end{traits::into_buf(data + offset, data + total, f)};
361 m_buffer.resize(
static_cast<std::size_t
>(end - data));
364 std::is_same_v<Field, std::string> or
365 std::is_same_v<Field, std::string_view> or
366 std::is_same_v<Field, zview>)
369 m_field_buf.resize(budget);
370 escape_field_to_buffer(f);
373 std::is_same_v<Field, std::optional<std::string>> or
374 std::is_same_v<Field, std::optional<std::string_view>> or
375 std::is_same_v<Field, std::optional<zview>>)
379 m_field_buf.resize(budget);
380 escape_field_to_buffer(f.value());
384 std::is_same_v<Field, std::unique_ptr<std::string>> or
385 std::is_same_v<Field, std::unique_ptr<std::string_view>> or
386 std::is_same_v<Field, std::unique_ptr<zview>> or
387 std::is_same_v<Field, std::shared_ptr<std::string>> or
388 std::is_same_v<Field, std::shared_ptr<std::string_view>> or
389 std::is_same_v<Field, std::shared_ptr<zview>>)
394 m_field_buf.resize(budget);
395 escape_field_to_buffer(*f);
401 m_field_buf.resize(budget);
402 auto const data{m_field_buf.data()};
403 escape_field_to_buffer(
404 traits::to_buf(data, data + std::size(m_field_buf), f));
416 template<
typename Field>
417 std::enable_if_t<nullness<Field>::always_null>
418 append_to_buffer(Field
const &)
420 m_buffer.append(null_field);
424 template<
typename Container>
425 std::enable_if_t<not std::is_same_v<typename Container::value_type, char>>
426 fill_buffer(Container
const &c)
431 std::size_t budget{0};
432 for (
auto const &f : c) budget += estimate_buffer(f);
433 m_buffer.reserve(budget);
434 for (
auto const &f : c) append_to_buffer(f);
438 template<
typename Tuple, std::size_t... indexes>
440 budget_tuple(Tuple
const &t, std::index_sequence<indexes...>)
442 return (estimate_buffer(std::get<indexes>(t)) + ...);
446 template<
typename Tuple, std::size_t... indexes>
447 void append_tuple(Tuple
const &t, std::index_sequence<indexes...>)
449 (append_to_buffer(std::get<indexes>(t)), ...);
453 template<
typename... Elts>
void fill_buffer(std::tuple<Elts...>
const &t)
455 using indexes = std::make_index_sequence<
sizeof...(Elts)>;
457 m_buffer.reserve(budget_tuple(t, indexes{}));
458 append_tuple(t, indexes{});
462 template<
typename... Ts>
void fill_buffer(
const Ts &...fields)
464 (..., append_to_buffer(fields));
467 constexpr static std::string_view s_classname{
"stream_to"};
471template<
typename Columns>
472inline stream_to::stream_to(
473 transaction_base &tx, std::string_view table_name, Columns
const &columns) :
474 stream_to{tx, table_name, std::begin(columns), std::end(columns)}
478template<
typename Iter>
479inline stream_to::stream_to(
480 transaction_base &tx, std::string_view table_name, Iter columns_begin,
487 return tx.quote_name(*col);
The home of all libpqxx classes, functions, templates, etc.
Definition array.cxx:27
std::string separated_list(std::string_view sep, ITER begin, ITER end, ACCESS access)
Represent sequence of values as a string, joined by a given separator.
Definition separated_list.hxx:46
std::size_t size_buffer(TYPE const &...value) noexcept
Estimate how much buffer space is needed to represent values as a string.
Definition strconv.hxx:525
constexpr bool is_null(TYPE const &value) noexcept
Is value null?
Definition strconv.hxx:514