A RemoteConnection object provides a bidirectional connection to another RemoteConnection object on a remote machine. More...

#include <remoteconnection.h>

Inheritance diagram for RemoteConnection:

Collaboration diagram for RemoteConnection:

Public Member Functions
	RemoteConnection (int fdin_, int fdout_, const std::string &context_=std::string())
	Constructor. More...

int	get_read_fd () const
	Return the underlying fd this remote connection reads from. More...

int	sniff_next_message_type (double end_time)
	Check what the next message type is. More...

int	get_message (std::string &result, double end_time)
	Read one message from fdin. More...

int	get_message_chunked (double end_time)
	Prepare to read one message from fdin in chunks. More...

int	get_message_chunk (std::string &result, size_t at_least, double end_time)
	Read a chunk of a message from fdin. More...

int	receive_file (const std::string &file, double end_time)
	Save the contents of a message as a file. More...

void	send_message (char type, std::string_view s, double end_time)
	Send a message. More...

void	send_file (char type, int fd, double end_time)
	Send the contents of a file as a message. More...

void	shutdown ()
	Shutdown the connection. More...

void	do_close ()
	Close the connection. More...

const std::string &	get_context () const
	Return the context to report with errors. More...

Protected Attributes
std::string	context
	The context to report with errors. More...

Private Member Functions
void	operator= (const RemoteConnection &)
	Don't allow assignment. More...

	RemoteConnection (const RemoteConnection &)
	Don't allow copying. More...

bool	read_at_least (size_t min_len, double end_time)
	Read until there are at least min_len bytes in buffer. More...

ssize_t	send_or_write (const void *p, size_t n)
	Helper which calls send() or write(). More...

Private Attributes
int	fdin
	The file descriptor used for reading. More...

int	fdout
	The file descriptor used for writing. More...

std::string	buffer
	Buffer to hold unprocessed input. More...

off_t	chunked_data_left
	Remaining bytes of message data still to come over fdin for a chunked read. More...

Detailed Description

A RemoteConnection object provides a bidirectional connection to another RemoteConnection object on a remote machine.

The connection is implemented using a pair of file descriptors. Messages with a single byte type code and arbitrary data as the contents can be sent and received.

Definition at line 41 of file remoteconnection.h.

Constructor & Destructor Documentation

◆ RemoteConnection() [1/2]

RemoteConnection::RemoteConnection ( const RemoteConnection & )

private

Don't allow copying.

◆ RemoteConnection() [2/2]

RemoteConnection::RemoteConnection	(	int	fdin_,
		int	fdout_,
		const std::string &	context_ = `std::string()`
	)

Constructor.

Definition at line 89 of file remoteconnection.cc.

References context, and fdout.

Member Function Documentation

◆ do_close()

void RemoteConnection::do_close ( )

Close the connection.

Definition at line 784 of file remoteconnection.cc.

References close_fd_or_socket(), fdin, fdout, and LOGCALL_VOID.

Referenced by RemoteDatabase::do_close(), and OwnedRemoteConnection::~OwnedRemoteConnection().

◆ get_context()

const std::string& RemoteConnection::get_context ( ) const

inline

Return the context to report with errors.

Definition at line 267 of file remoteconnection.h.

References context.

Referenced by RemoteDatabase::get_backend_info(), RemoteDatabase::get_description(), RemoteDatabase::get_doclength(), RemoteDatabase::get_freqs(), RemoteDatabase::get_message(), RemoteDatabase::get_unique_terms(), RemoteDatabase::get_wdfdocmax(), RemoteDatabase::open_term_list(), RemoteDatabase::positionlist_count(), RemoteDatabase::read_value_stats(), RemoteDatabase::remove_spelling(), and RemoteDatabase::update_stats().

◆ get_message()

int RemoteConnection::get_message	(	std::string &	result,
		double	end_time
	)

Read one message from fdin.

Parameters

[out]	result	Message data.
	end_time	If this time is reached, then a timeout exception will be thrown. If (end_time == 0.0) then the operation will never timeout.

Returns: Message type code or -1 for EOF.

Definition at line 593 of file remoteconnection.cc.

References buffer, RealTime::end_time(), fdin, LOGCALL, p, read_at_least(), RETURN, throw_database_closed(), and unpack_uint().

Referenced by RemoteServer::get_message(), RemoteDatabase::get_message(), ReplicateTcpServer::handle_one_connection(), and RemoteDatabase::send_message().

◆ get_message_chunk()

int RemoteConnection::get_message_chunk	(	std::string &	result,
		size_t	at_least,
		double	end_time
	)

Read a chunk of a message from fdin.

You must call get_message_chunked() before calling this method.

Parameters

[in,out]	result	Message data. This is appended to, so if you read more than needed the previous time, leave the excess in result.
	at_least	Return at least this many bytes in result, unless there isn't enough data left in the message (in which case all remaining data is read and 0 is returned).
	end_time	If this time is reached, then a timeout exception will be thrown. If (end_time == 0.0) then the operation will never timeout.

Returns: 1 if at least at_least bytes are now in result; -1 on EOF on the connection; 0 for having read < at_least bytes, but finished the message.

Definition at line 674 of file remoteconnection.cc.

References buffer, chunked_data_left, RealTime::end_time(), fdin, LOGCALL, read_at_least(), RETURN, and throw_database_closed().

Referenced by GlassDatabaseReplicator::apply_changeset_from_conn(), GlassDatabaseReplicator::process_changeset_chunk_blocks(), and GlassDatabaseReplicator::process_changeset_chunk_version().

◆ get_message_chunked()

int RemoteConnection::get_message_chunked ( double end_time )

Prepare to read one message from fdin in chunks.

Sometimes a message can be sufficiently large that you don't want to read it all into memory before processing it. Also, it may be more efficient to process it as you go.

This method doesn't actually return any message data - call get_message_chunk() to do that.

Parameters

end_time If this time is reached, then a timeout exception will be thrown. If (end_time == 0.0) then the operation will never timeout.

Returns: Message type code or -1 for EOF.

Definition at line 633 of file remoteconnection.cc.

References buffer, chunked_data_left, RealTime::end_time(), fdin, LOGCALL, p, rare, read_at_least(), RETURN, throw_database_closed(), throw_network_error_message_too_long_for_off_t(), and unpack_uint().

Referenced by GlassDatabaseReplicator::apply_changeset_from_conn(), and receive_file().

◆ get_read_fd()

int RemoteConnection::get_read_fd ( ) const

inline

Return the underlying fd this remote connection reads from.

Definition at line 147 of file remoteconnection.h.

References fdin.

Referenced by RemoteDatabase::get_read_fd().

◆ operator=()

void RemoteConnection::operator= ( const RemoteConnection & )

private

Don't allow assignment.

◆ read_at_least()

bool RemoteConnection::read_at_least	(	size_t	min_len,
		double	end_time
	)

private

Read until there are at least min_len bytes in buffer.

If for some reason this isn't possible, returns false upon EOF and otherwise throws NetworkError.

Parameters

min_len	Minimum number of bytes required in buffer.
end_time	If this time is reached, then a timeout exception will be thrown. If (end_time == 0.0), then keep trying indefinitely.

Returns: false on EOF, otherwise true.

Definition at line 157 of file remoteconnection.cc.

References Assert, buffer, CHUNKSIZE, context, RealTime::end_time(), fdin, LOGCALL, LOGLINE, RealTime::now(), RETURN, RealTime::sleep(), throw_timeout(), and RealTime::to_timeval().

Referenced by get_message(), get_message_chunk(), get_message_chunked(), receive_file(), and sniff_next_message_type().

◆ receive_file()

int RemoteConnection::receive_file	(	const std::string &	file,
		double	end_time
	)

Save the contents of a message as a file.

Parameters

file	Path to file to save the message data into. If the file exists it will be overwritten.
end_time	If this time is reached, then a timeout exception will be thrown. If (end_time == 0.0) then the operation will never timeout.

Returns: Message type code or -1 for EOF.

Definition at line 714 of file remoteconnection.cc.

References buffer, chunked_data_left, CHUNKSIZE, RealTime::end_time(), fdin, get_message_chunked(), LOGCALL, O_CLOEXEC, posixy_open, read_at_least(), RETURN, throw_database_closed(), and write_all().

◆ send_file()

void RemoteConnection::send_file	(	char	type,
		int	fd,
		double	end_time
	)

Send the contents of a file as a message.

Parameters

type	Message type code.
fd	File containing the message data.
end_time	If this time is reached, then a timeout exception will be thrown. If (end_time == 0.0) then the operation will never timeout.

Definition at line 428 of file remoteconnection.cc.

References AssertRel, CHUNKSIZE, context, RealTime::end_time(), fdout, file_size(), LOGCALL_VOID, LOGLINE, RealTime::now(), pack_uint(), POLLSELECT, send_or_write(), RealTime::sleep(), throw_database_closed(), throw_timeout(), and RealTime::to_timeval().

Referenced by GlassDatabase::send_whole_database(), and GlassDatabase::write_changesets_to_fd().

◆ send_message()

void RemoteConnection::send_message	(	char	type,
		std::string_view	s,
		double	end_time
	)

Send a message.

Parameters

type	Message type code.
s	Message data.
end_time	If this time is reached, then a timeout exception will be thrown. If (end_time == 0.0) then the operation will never timeout.

Definition at line 300 of file remoteconnection.cc.

References context, RealTime::end_time(), fdout, LOGCALL_VOID, LOGLINE, RealTime::now(), pack_uint(), POLLSELECT, send_or_write(), RealTime::sleep(), Xapian::Internal::str(), throw_database_closed(), throw_timeout(), and RealTime::to_timeval().

Referenced by RemoteDatabase::send_message(), RemoteServer::send_message(), GlassDatabase::send_whole_database(), shutdown(), Xapian::DatabaseMaster::write_changesets_to_fd(), and GlassDatabase::write_changesets_to_fd().

◆ send_or_write()

ssize_t RemoteConnection::send_or_write	(	const void *	p,
		size_t	n
	)

private

Helper which calls send() or write().

Definition at line 283 of file remoteconnection.cc.

References fdout, p, and usual.

Referenced by send_file(), and send_message().

◆ shutdown()

void RemoteConnection::shutdown ( )

Shutdown the connection.

Sends a shutdown message to the server and waits for it to close its end of the connection.

Definition at line 738 of file remoteconnection.cc.

References dummy, fdin, LOGCALL_VOID, MSG_SHUTDOWN, and send_message().

Referenced by RemoteDatabase::do_close().

◆ sniff_next_message_type()

int RemoteConnection::sniff_next_message_type ( double end_time )

Check what the next message type is.

This must not be called after a call to get_message_chunked() until get_message_chunk() has returned 0 to indicate the whole message has been received.

Other than that restriction, this may be called at any time to determine what the next message waiting to be processed is: it will not affect subsequent calls which read messages.

Parameters

end_time If this time is reached, then a timeout exception will be thrown. If (end_time == 0.0) then the operation will never timeout.

Returns: Message type code or -1 for EOF.

Definition at line 580 of file remoteconnection.cc.

References buffer, RealTime::end_time(), fdin, LOGCALL, read_at_least(), RETURN, and throw_database_closed().

Member Data Documentation

◆ buffer

std::string RemoteConnection::buffer

private

Buffer to hold unprocessed input.

Definition at line 91 of file remoteconnection.h.

Referenced by get_message(), get_message_chunk(), get_message_chunked(), read_at_least(), receive_file(), and sniff_next_message_type().

◆ chunked_data_left

off_t RemoteConnection::chunked_data_left

private

Remaining bytes of message data still to come over fdin for a chunked read.

Definition at line 94 of file remoteconnection.h.

Referenced by get_message_chunk(), get_message_chunked(), and receive_file().

◆ context

std::string RemoteConnection::context

protected

The context to report with errors.

Subclasses are allowed to manage this.

Definition at line 134 of file remoteconnection.h.

Referenced by get_context(), read_at_least(), RemoteConnection(), RemoteServer::RemoteServer(), send_file(), and send_message().

◆ fdin

int RemoteConnection::fdin

private

The file descriptor used for reading.

If this is -1, the connection is unidirectional and write-only. If both fdin and fdout are -1, then the connection has been closed.

Definition at line 53 of file remoteconnection.h.

Referenced by do_close(), get_message(), get_message_chunk(), get_message_chunked(), get_read_fd(), read_at_least(), receive_file(), shutdown(), and sniff_next_message_type().

◆ fdout

int RemoteConnection::fdout

private

The file descriptor used for writing.

If this is -1, the connection is unidirectional and read-only. If both fdin and fdout are -1, then the connection has been closed. It is valid for fdout to be the same as fdin.

Definition at line 61 of file remoteconnection.h.

Referenced by do_close(), RemoteConnection(), send_file(), send_message(), and send_or_write().

The documentation for this class was generated from the following files:

net/remoteconnection.h
net/remoteconnection.cc

Public Member Functions

Protected Attributes

Private Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ RemoteConnection() [1/2]

◆ RemoteConnection() [2/2]

Member Function Documentation

◆ do_close()

◆ get_context()

◆ get_message()

◆ get_message_chunk()

◆ get_message_chunked()

◆ get_read_fd()

◆ operator=()

◆ read_at_least()

◆ receive_file()

◆ send_file()

◆ send_message()

◆ send_or_write()

◆ shutdown()

◆ sniff_next_message_type()

Member Data Documentation

◆ buffer

◆ chunked_data_left

◆ context

◆ fdin

◆ fdout