ozo::pooled_connection< Rep, Executor > Class Template Reference

#include <ozo/connection_pool.h>

Description

template<typename Rep, typename Executor = asio::io_context::executor_type>
class ozo::pooled_connection< Rep, Executor >

Pool bound model for Connection concept.

Connection concept model which is bound to and may be obtained only from the connection pool. On the pooled_connection object destruction, the underlying handle that contains a connection will be returned to the handle-associated connection pool. If the connection is in a bad state either its current transaction status is different than ozo::transaction_status::idle then it will not return to the pool and be closed. The class object is non-copyable.

Template Parameters

Rep	— underlying connection pool representation for the real connection.
Executor	— the type of the executor is used to perform IO; currently only boost::asio::io_context::executor_type is supported.

Thread safety

Distinct objects: Safe
Shared objects: Unsafe

Models

Connection

Types
using	rep_type = Rep
	Connection representation type.
using	native_handle_type = typename connection_traits< rep_type >::native_handle_type
	Native connection handle type.
using	oid_map_type = typename connection_traits< rep_type >::oid_map_type
	Oid map of types that are used with the connection.
using	error_context_type = typename connection_traits< rep_type >::error_context_type
	Additional error context which could provide context depended information for errors.
using	statistics_type = typename connection_traits< rep_type >::statistics_type
	Connection statistics to be collected.
using	executor_type = Executor
	The type of the executor associated with the object.

Public Member Functions
native_handle_type	native_handle () const noexcept
const oid_map_type &	oid_map () const noexcept
const error_context_type &	get_error_context () const noexcept
void	set_error_context (error_context_type v={})
executor_type	get_executor () const noexcept
template<typename WaitHandler >
void	async_wait_write (WaitHandler &&handler)
template<typename WaitHandler >
void	async_wait_read (WaitHandler &&handler)
error_code	close () noexcept
void	cancel () noexcept
bool	is_bad () const noexcept
	operator bool () const noexcept
bool	is_open () const noexcept

Member Function Documentation

async_wait_read()

template<typename Rep , typename Executor >

template<typename WaitHandler >

void ozo::pooled_connection< Rep, Executor >::async_wait_read

(

WaitHandler &&

handler

)

Asynchronously wait for the connection socket to become ready to read or to have pending error conditions.

Typically this function is used by the library within the connection establishing process and operation execution. Users should not use it directly other than for custom libpq-based opeartions.

Warning

The function is designated to the library operations use only. Do not call this function directly.

Parameters

handler

— wait handler with void(ozo::error_code, int=0) signature.

async_wait_write()

template<typename Rep , typename Executor >

template<typename WaitHandler >

void ozo::pooled_connection< Rep, Executor >::async_wait_write

(

WaitHandler &&

handler

)

Asynchronously wait for the connection socket to become ready to write or to have pending error conditions.

Typically this function is used by the library within the connection establishing process and operation execution. Users should not use it directly other than for custom libpq-based opeartions.

Warning

The function is designated to the library operations use only. Do not call this function directly.

Parameters

handler

— wait handler with void(ozo::error_code, int=0) signature.

cancel()

template<typename Rep , typename Executor >

void ozo::pooled_connection< Rep, Executor >::cancel

noexcept

Cancel all asynchronous operations associated with the connection.

This function causes all outstanding asynchronous operations to finish immediately, and the handlers for cancelled operations will be passed the boost::asio::error::operation_aborted error.

close()

template<typename Rep , typename Executor >

error_code ozo::pooled_connection< Rep, Executor >::close

noexcept

Close the connection.

Any asynchronous operations will be cancelled immediately, and will complete with the boost::asio::error::operation_aborted error.

Returns

error_code - indicates what error occurred, if any. Note that, even if the function indicates an error, the underlying connection is closed.

References ozo::unwrap().

get_error_context()

template<typename Rep , typename Executor = asio::io_context::executor_type>

const error_context_type& ozo::pooled_connection< Rep, Executor >::get_error_context ( ) const

noexcept

Get the additional context object for an error that occurred during the last operation on the connection.

Returns

const error_context& — additional context for the error

References ozo::unwrap().

get_executor()

template<typename Rep , typename Executor = asio::io_context::executor_type>

executor_type ozo::pooled_connection< Rep, Executor >::get_executor ( ) const

noexcept

Get the executor associated with the object.

Returns

executor_type — executor object.

is_bad()

template<typename Rep , typename Executor >

bool ozo::pooled_connection< Rep, Executor >::is_bad

noexcept

Determine whether the connection is in bad state.

Returns

false — connection established, and it is ok to execute operations

true — connection is not established, no operation shall be performed, but an error context may be obtained via get_error_context() and ozo::error_message().

Referenced by ozo::pooled_connection< Rep, Executor >::operator bool().

is_open()

template<typename Rep , typename Executor = asio::io_context::executor_type>

bool ozo::pooled_connection< Rep, Executor >::is_open ( ) const

noexcept

Determine whether the connection is open.

Returns

false — connection is closed and no native handle associated with.

true — connection is open and there is a native handle associated with.

References ozo::pooled_connection< Rep, Executor >::native_handle().

native_handle()

template<typename Rep , typename Executor >

pooled_connection< Rep, Executor >::native_handle_type ozo::pooled_connection< Rep, Executor >::native_handle

noexcept

Get native connection handle object.

This function may be used to obtain the underlying representation of the connection. This is intended to allow access to native libpq functionality that is not otherwise provided.

Returns

native_handle_type — native connection handle.

References ozo::unwrap().

Referenced by ozo::pooled_connection< Rep, Executor >::is_open().

oid_map()

template<typename Rep , typename Executor = asio::io_context::executor_type>

const oid_map_type& ozo::pooled_connection< Rep, Executor >::oid_map ( ) const

noexcept

Get a reference to an oid map object for types that are used with the connection.

Returns

const oid_map_type& — reference on oid map object.

References ozo::unwrap().

operator bool()

template<typename Rep , typename Executor = asio::io_context::executor_type>

ozo::pooled_connection< Rep, Executor >::operator bool ( ) const

noexcept

Determine whether the connection is not in bad state.

Returns

true — connection established, and it is ok to execute operations

false — connection is not established, no operation shall be performed, but an error context may be obtained via get_error_context() and ozo::error_message().

References ozo::pooled_connection< Rep, Executor >::is_bad().

set_error_context()

template<typename Rep , typename Executor = asio::io_context::executor_type>

void ozo::pooled_connection< Rep, Executor >::set_error_context

(

error_context_type

v = {}

)

Set the additional error context object. This function may be used to provide additional context-depended data that is related to the current operation error.

Parameters

v	— new error context.