engine::io::Socket Class Reference

#include <userver/engine/io/socket.hpp>

Detailed Description

Socket representation.

It is not thread-safe to concurrently read from socket. It is not thread-safe to concurrently write to socket. However it is safe to concurrently read and write into socket:

    // Sending and receiving data from self on the same socket
    engine::io::Socket& socket = listener.socket;
    auto read_task = engine::AsyncNoSpan([&socket, &deadline] {
        for (char expected_data = 0; expected_data <= 100; ++expected_data) {
            char c = 0;
            const auto recvfrom = socket.RecvSomeFrom(&c, 1, deadline);
            EXPECT_EQ(1, recvfrom.bytes_received);
            EXPECT_EQ(expected_data, c);
        }
    });
 
    const auto& addr = socket.Getsockname();
    for (char send_data = 0; send_data <= 100; ++send_data) {
        const auto bytes_sent = socket.SendAllTo(addr, &send_data, 1, deadline);
        EXPECT_EQ(bytes_sent, 1);
    }
 
    read_task.Get();

Examples

samples/tcp_full_duplex_service/main.cpp, and samples/tcp_service/main.cpp.

Definition at line 37 of file socket.hpp.

Inheritance diagram for engine::io::Socket:

Classes
struct	RecvFromResult

Public Member Functions
	Socket ()=default
	Constructs an invalid socket.
	Socket (AddrDomain, SocketType)
	Constructs a socket for the address domain of specified type.
	Socket (int fd, AddrDomain domain=AddrDomain::kUnspecified)
	Adopts an existing socket for specified address domain.
	operator bool () const
	Whether the socket is valid.
bool	IsValid () const override
	Whether the socket is valid.
void	Connect (const Sockaddr &, Deadline)
	Connects the socket to a specified endpoint.
void	Bind (const Sockaddr &)
	Binds the socket to the specified endpoint.
void	Listen (int backlog=SOMAXCONN)
	Starts listening for connections on a specified socket (must be bound).
bool	WaitReadable (Deadline) override
bool	WaitWriteable (Deadline) override
size_t	RecvSome (void *buf, size_t len, Deadline deadline)
	Receives at least one byte from the socket.
size_t	RecvAll (void *buf, size_t len, Deadline deadline)
	Receives exactly len bytes from the socket.
std::optional< size_t >	RecvNoblock (void *buf, size_t len)
	Receives up to len bytes from the stream.
size_t	SendAll (std::initializer_list< IoData > list, Deadline deadline)
	Sends a buffer vector to the socket.
size_t	WriteAll (std::initializer_list< IoData > list, Deadline deadline) override
size_t	SendAll (const IoData *list, std::size_t list_size, Deadline deadline)
	Sends exactly list_size IoData to the socket.
size_t	SendAll (const struct iovec *list, std::size_t list_size, Deadline deadline)
	Sends exactly list_size iovec to the socket.
size_t	SendAll (const void *buf, size_t len, Deadline deadline)
	Sends exactly len bytes to the socket.
Socket	Accept (Deadline)
	Accepts a connection from a listening socket.
RecvFromResult	RecvSomeFrom (void *buf, size_t len, Deadline deadline)
	Receives at least one byte from the socket, returning source address.
size_t	SendAllTo (const Sockaddr &dest_addr, const void *buf, size_t len, Deadline deadline)
	Sends exactly len bytes to the specified address via the socket.
int	Fd () const
	File descriptor corresponding to this socket.
const Sockaddr &	Getpeername ()
	Address of a remote peer.
const Sockaddr &	Getsockname ()
	Local socket address.
int	Release () &&noexcept
	Releases file descriptor and invalidates the socket.
void	Close ()
	Closes and invalidates the socket.
int	GetOption (int layer, int optname) const
	Retrieves a socket option.
void	SetOption (int layer, int optname, int optval)
	Sets a socket option.
size_t	ReadSome (void *buf, size_t len, Deadline deadline) override
	Receives at least one byte from the socket.
size_t	ReadAll (void *buf, size_t len, Deadline deadline) override
	Receives exactly len bytes from the socket.
std::optional< size_t >	ReadNoblock (void *buf, size_t len) override
	Receives up to len bytes from the stream.
size_t	WriteAll (const void *buf, size_t len, Deadline deadline) override
	Writes exactly len bytes to the socket.
ReadableBase &	GetReadableBase ()
WritableBase &	GetWritableBase ()
impl::ContextAccessor *	TryGetContextAccessor ()
	For internal use only.
impl::ContextAccessor *	TryGetContextAccessor ()
	For internal use only.

Protected Member Functions
void	SetReadableContextAccessor (impl::ContextAccessor *ca)
void	SetWritableContextAccessor (impl::ContextAccessor *ca)

Constructor & Destructor Documentation

Socket()

engine::io::Socket::Socket ( int  fd, AddrDomain  domain = AddrDomain::kUnspecified  )

explicit

Adopts an existing socket for specified address domain.

Note

File descriptor will be silently forced to nonblocking mode.

Member Function Documentation

Accept()

Socket engine::io::Socket::Accept

(

Deadline

)

Accepts a connection from a listening socket.

See also

engine::io::Listen

Bind()

void engine::io::Socket::Bind

(

const Sockaddr &

)

Binds the socket to the specified endpoint.

Note

Sockaddr domain must match the socket's domain.

Close()

void engine::io::Socket::Close

(

)

Closes and invalidates the socket.

Warning

You should not call Close with pending I/O. This may work okay sometimes but it's loosely predictable.

Connect()

void engine::io::Socket::Connect	(	const Sockaddr &	,
		Deadline
	)

Connects the socket to a specified endpoint.

Note

Sockaddr domain must match the socket's domain.

GetReadableBase()

ReadableBase & engine::io::RwBase::GetReadableBase ( )

inlineinherited

Definition at line 110 of file common.hpp.

GetWritableBase()

WritableBase & engine::io::RwBase::GetWritableBase ( )

inlineinherited

Definition at line 112 of file common.hpp.

IsValid()

bool engine::io::Socket::IsValid ( ) const

overridevirtual

Whether the socket is valid.

Implements engine::io::ReadableBase.

operator bool()

engine::io::Socket::operator bool ( ) const

inlineexplicit

Whether the socket is valid.

Definition at line 55 of file socket.hpp.

ReadAll()

size_t engine::io::Socket::ReadAll ( void *  buf, size_t  len, Deadline  deadline  )

inlineoverridevirtual

Receives exactly len bytes from the socket.

Note

Can return less than len if socket is closed by peer.

Implements engine::io::ReadableBase.

Definition at line 166 of file socket.hpp.

ReadNoblock()

std::optional< size_t > engine::io::Socket::ReadNoblock ( void *  buf, size_t  len  )

inlineoverridevirtual

Receives up to len bytes from the stream.

Returns

• nullopt on data absence
• optional{0} if socket is closed by peer.
• optional{data_bytes_available} otherwise, 1 <= data_bytes_available <= len

Reimplemented from engine::io::ReadableBase.

Definition at line 176 of file socket.hpp.

ReadSome()

size_t engine::io::Socket::ReadSome ( void *  buf, size_t  len, Deadline  deadline  )

inlineoverridevirtual

Receives at least one byte from the socket.

Returns

0 if connection is closed on one side and no data could be received any more, received bytes count otherwise.

Implements engine::io::ReadableBase.

Examples

samples/tcp_full_duplex_service/main.cpp.

Definition at line 160 of file socket.hpp.

RecvAll()

size_t engine::io::Socket::RecvAll	(	void *	buf,
		size_t	len,
		Deadline	deadline
	)

Receives exactly len bytes from the socket.

Note

Can return less than len if socket is closed by peer.

RecvNoblock()

std::optional< size_t > engine::io::Socket::RecvNoblock	(	void *	buf,
		size_t	len
	)

Receives up to len bytes from the stream.

Returns

• nullopt on data absence
• optional{0} if socket is closed by peer.
• optional{data_bytes_available} otherwise, 1 <= data_bytes_available <= len

RecvSome()

size_t engine::io::Socket::RecvSome	(	void *	buf,
		size_t	len,
		Deadline	deadline
	)

Receives at least one byte from the socket.

Returns

0 if connection is closed on one side and no data could be received any more, received bytes count otherwise.

RecvSomeFrom()

RecvFromResult engine::io::Socket::RecvSomeFrom	(	void *	buf,
		size_t	len,
		Deadline	deadline
	)

Receives at least one byte from the socket, returning source address.

Returns

0 in bytes_sent if connection is closed on one side and no data could be received any more, received bytes count otherwise + source address.

SendAll() [1/4]

size_t engine::io::Socket::SendAll	(	const IoData *	list,
		std::size_t	list_size,
		Deadline	deadline
	)

Sends exactly list_size IoData to the socket.

Note

Can return less than len if socket is closed by peer.

SendAll() [2/4]

size_t engine::io::Socket::SendAll	(	const struct iovec *	list,
		std::size_t	list_size,
		Deadline	deadline
	)

Sends exactly list_size iovec to the socket.

Note

Can return less than len if socket is closed by peer.

SendAll() [3/4]

size_t engine::io::Socket::SendAll	(	const void *	buf,
		size_t	len,
		Deadline	deadline
	)

Sends exactly len bytes to the socket.

Note

Can return less than len if socket is closed by peer.

SendAll() [4/4]

size_t engine::io::Socket::SendAll	(	std::initializer_list< IoData >	list,
		Deadline	deadline
	)

Sends a buffer vector to the socket.

Note

Can return less than len if socket is closed by peer.

    const auto bytes_sent = sockets.second.SendAll({{"data", 4}, {"chunk 1", 7}, {"chunk 2", 7}}, deadline);

Examples

samples/tcp_full_duplex_service/main.cpp.

SendAllTo()

size_t engine::io::Socket::SendAllTo	(	const Sockaddr &	dest_addr,
		const void *	buf,
		size_t	len,
		Deadline	deadline
	)

Sends exactly len bytes to the specified address via the socket.

Note

Can return less than len in bytes_sent if socket is closed by peer.

Sockaddr domain must match the socket's domain.

Not for SocketType::kStream connections, see man sendto.

SetReadableContextAccessor()

void engine::io::ReadableBase::SetReadableContextAccessor ( impl::ContextAccessor *  ca )

inlineprotectedinherited

Definition at line 58 of file common.hpp.

SetWritableContextAccessor()

void engine::io::WritableBase::SetWritableContextAccessor ( impl::ContextAccessor *  ca )

inlineprotectedinherited

Definition at line 96 of file common.hpp.

TryGetContextAccessor() [1/2]

impl::ContextAccessor * engine::io::ReadableBase::TryGetContextAccessor ( )

inlineinherited

For internal use only.

Definition at line 55 of file common.hpp.

TryGetContextAccessor() [2/2]

impl::ContextAccessor * engine::io::WritableBase::TryGetContextAccessor ( )

inlineinherited

For internal use only.

Definition at line 93 of file common.hpp.

WaitReadable()

bool engine::io::Socket::WaitReadable ( Deadline  )

overridevirtual

Suspends current task until the socket has data available.

Returns

false on timeout or on task cancellations; true otherwise.

Implements engine::io::ReadableBase.

WaitWriteable()

bool engine::io::Socket::WaitWriteable ( Deadline  )

overridevirtual

Suspends current task until the socket can accept more data.

Returns

false on timeout or on task cancellations; true otherwise.

Implements engine::io::WritableBase.

WriteAll() [1/2]

size_t engine::io::Socket::WriteAll ( const void *  buf, size_t  len, Deadline  deadline  )

inlineoverridevirtual

Writes exactly len bytes to the socket.

Note

Can return less than len if socket is closed by peer.

Implements engine::io::WritableBase.

Definition at line 180 of file socket.hpp.

WriteAll() [2/2]

size_t engine::io::Socket::WriteAll ( std::initializer_list< IoData >  list, Deadline  deadline  )

inlineoverridevirtual

Reimplemented from engine::io::WritableBase.

Definition at line 101 of file socket.hpp.

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

• userver/engine/io/socket.hpp