CODEX_Quorum::SocketBase Class Reference

This class handles basic socket operations. More...

#include <Socket.h>

Inheritance diagram for CODEX_Quorum::SocketBase:

[legend]List of all members.

Public Types
typedef std::queue< Message * >	MsgQueueType
	Outgoing messages are kept in a queue.
enum	StateType { kRead, kWrite, kError }
	Type of state to check.
Public Member Functions
Socket Creation and Maintenance
These functions, including constructors and a destructor, create, maintain, and destroy sockets. In addition to construction, this also includes setting up sockets to receive incoming connections and establishing incoming and outgoing connections.
	SocketBase (int domain=PF_INET, int type=SOCK_STREAM, int protocol=0, bool blocking=false)
	The constructor creates a socket(2).
virtual	~SocketBase ()
virtual void	setup (int port, int backlog)
	This version of SocketBase::setup() assumes an IPv4 socket.
virtual void	setup (struct sockaddr *my_addr, socklen_t addrlen, int backlog)
	This version of SocketBase::setup() allows for other varieties of sockets aside from IPv4.
virtual void	connect (const RemoteServer &server)
	This replaces the standard C connect(2) function, calling the standard function in the base class (with all arguments handled transparently to the user) and allowing refinements in derived classes.
virtual SocketBase *	accept ()
	This replaces the standard C accept(2) function, calling the standard function in the base class (with all arguments handled transparently to the user) and allowing refinements in derived classes.
Socket I/O
These functions handle basic socket I/O.
virtual size_t	readFrom (void *output, size_t maxSize=1024) const
	Read data from a socket.
virtual size_t	readAll (Message &msg, size_t length=0) const
	This method reads an entire message from the socket, using the message length information encoded in the packet.
virtual void	writeTo (const Message &input) const
	Write data to a socket.
virtual int	set_fd (fd_set *fd_bitmap, StateType s) const
	Fill file descriptor bitmap.
virtual bool	isset_fd (const fd_set *fd_bitmap, StateType s) const
	Check file descriptor bitmap.
virtual void	flush () const
	Force a blocking write of the internal buffer.
Protected Member Functions
virtual int	internal_write (const unsigned char *output, size_t maxSize) const
	Write data to the socket.
Protected Constructors
These functions allow controlled construction of new SocketBase%s.
	SocketBase (const SocketBase &aOther)
	Copy constructor.
virtual SocketBase *	clone ()
	Subclass-aware object duplication.
Protected Setup and Maintenance Methods
These methods implement the functionality of their non-protected counterparts. This allows derived classes to use the public methods without having to fully reimplement the base class methods.
virtual SocketBase *	protected_accept ()
	Exceptions: QSESocketBaseAcceptFailed
virtual void	finish_accept ()
	Post-creation method called by protected_accept().
virtual void	protected_bind (int port)
virtual void	protected_bind (struct sockaddr *my_addr, socklen_t addrlen)
	Exceptions: QSESocketBaseCannotBind
virtual void	protected_listen (int backlog)
	Exceptions: QSESocketBaseListenFailed
void	setSocket (int socketFD)
void	setBacklog (int backlog)
void	setPort (int port)
Protected Accessors
These accessor methods allow derived classes to read, but not modify, private member data.
int	domain () const
int	type () const
int	protocol () const
bool	blocking () const
int	port () const
int	backlog () const
int	socket () const
Protected Attributes
MsgQueueType	m_msgQueue
	Message queue, which allows us to do in-order non-blocking writes.
unsigned int	m_msgOffset
	Offset into the buffer of the first message on the queue.

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Detailed Description

This class handles basic socket operations.

Definition at line 38 of file Socket.h.

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Constructor & Destructor Documentation

SocketBase::SocketBase (  int  domain = PF_INET, int  type = SOCK_STREAM, int  protocol = 0, bool  blocking = false )

The constructor creates a socket(2). Additional configuration, such as bind(2) and listen(2) must be done after construction. The default values establish an IPv4 TCP socket. Parameters: domain  Selects protocol domain, such as PF_UNIX, PF_INET, or PF_INET6. type  Selects the type of socket, such as SOCK_STREAM, SOCK_DGRAM, or SOCK_RAW. protocol  Selects the protocol to use. blocking  Should sockets produced by accept(2) block? Exceptions: QSESocketBaseBadSocket  if the socket cannot be created. Definition at line 36 of file Socket.cc. Referenced by clone().

SocketBase::SocketBase (  const SocketBase &  aOther  )  [protected]

Copy constructor. The copy constructor does not create a new socket, but rather copies the configuration of the original socket. This is used when accept%ing connections, where the listening socket is clone%d for each incoming connection. Definition at line 55 of file Socket.cc.

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Member Function Documentation

SocketBase * SocketBase::accept (   )  [virtual]

This replaces the standard C accept(2) function, calling the standard function in the base class (with all arguments handled transparently to the user) and allowing refinements in derived classes. The connection information is held within the member data of SocketBase. As the standard accept(2) returns a new socket filehandle, this version acts as a clone function. The bulk of the work is handled in the protected member function SocketBase::protected_accept(), which should be called by derived-class reimplementations of SocketBase::accept(). Returns: pointer to a SocketBase containing connection information. This should be deleted by the caller when no longer needed. Exceptions: QSESocketBaseAcceptFailed  if the call to accept(2) fails. Note that this might not be a fatal error for a non-blocking socket, in which case an invocation may look like: try { SocketBase* newConnection = listeningSocket->accept(); // read from socket newConnection } catch( QSESocketBaseAcceptFailed& err ) { // no data to read } Reimplemented in CODEX_Quorum::LoopbackSocket. Definition at line 97 of file Socket.cc. References protected_accept(). Referenced by CODEX_Quorum::EchoServer::processRequest().

SocketBase * SocketBase::clone (   )  [protected, virtual]

Subclass-aware object duplication. This is similar to a copy constructor except that, as a virtual function, it can be overridden in order for derived classes to return copies of themselves that have the correct type, yet which use an identical interface from the base class. Each class in the SocketBase hierarchy overrides this method to use its own copy constructor. Reimplemented in CODEX_Quorum::LoopbackSocket, and CODEX_SSL::SSLSocket. Definition at line 374 of file Socket.cc. References SocketBase(). Referenced by protected_accept().

void SocketBase::connect (  const RemoteServer &  server  )  [virtual]

This replaces the standard C connect(2) function, calling the standard function in the base class (with all arguments handled transparently to the user) and allowing refinements in derived classes. Parameters: server  Object defining the server to which this socket should connect Return values: true  if connection is successful false  if connection fails Reimplemented in CODEX_Quorum::LoopbackSocket. Definition at line 88 of file Socket.cc. Referenced by CODEX_SSL::SSLSocket::connect(), and CODEX_Quorum::RemoteServer::socket().

void SocketBase::finish_accept (   )  [protected, virtual]

Post-creation method called by protected_accept(). The default version of this method does nothing. It exists so that derived classes may add their own setup after accept(2) has run, but before the actual type is lost by the socket being returned as a pointer to SocketBase. Reimplemented in CODEX_SSL::SSLSocket. Definition at line 369 of file Socket.cc. Referenced by protected_accept().

void SocketBase::flush (   )  const [virtual]

Force a blocking write of the internal buffer. Reads are not affected. Single-threaded servers should not call this, but it's fine for multi-threaded servers and clients that want to block until they get a response. Reimplemented in CODEX_Quorum::LoopbackSocket. Definition at line 282 of file Socket.cc. References CODEX_Quorum::Message::buffer(), internal_write(), CODEX_Quorum::Message::length(), m_msgOffset, and m_msgQueue. Referenced by CODEX_Quorum::RemoteServer::flushSocket().

int SocketBase::internal_write (  const unsigned char *  output, size_t  maxSize )  const [protected, virtual]

Write data to the socket. Derived classes that need special semantics for writing but can still use the select(2) mechanism, such as for SSL, only need to override this method. The public writeTo() method is SSL-clean. Parameters: output  Buffer containing the data to write maxSize  Maximum number of bytes to write Returns: Number of bytes written Exceptions: QSESocketBaseWriteFailed  An error occurred during writing. Reimplemented in CODEX_SSL::SSLSocket. Definition at line 314 of file Socket.cc. Referenced by flush(), and isset_fd().

bool SocketBase::isset_fd (  const fd_set *  fd_bitmap, StateType  s )  const [virtual]

Check file descriptor bitmap. Parameters: fd_bitmap  bitmap of file descriptors to check. This is typically a fd_set returned by select(2), and will have the bit corresponding to the socket file descriptor set to 1 if the relevant action is appropriate. s  state of the socket to be tested. This allows derived classes to manipulate the return value appropriately when there is additional socket state to consider. Return values: true  the bit is set false  the bit is not set Definition at line 242 of file Socket.cc. References CODEX_Quorum::Message::buffer(), internal_write(), CODEX_Quorum::Message::length(), m_msgOffset, m_msgQueue, and set_fd(). Referenced by CODEX_SSL::SSLSocket::isset_fd(), CODEX_Quorum::RemoteServer::isset_fd(), CODEX_Quorum::LocalServer::isset_fd(), CODEX_Quorum::EchoServer::processRequest(), and readAll().

void SocketBase::protected_bind (  struct sockaddr *  my_addr, socklen_t  addrlen )  [protected, virtual]

Exceptions: QSESocketBaseCannotBind  Bug: This may not be the right place to call setsockopt(2), and it may not always be appropriate to call it. Todo: Make a real setsockopt interface. Definition at line 402 of file Socket.cc. Referenced by setup().

size_t SocketBase::readAll (  Message &  msg, size_t  length = 0 )  const [virtual]

This method reads an entire message from the socket, using the message length information encoded in the packet. If reading the entire message would block, the available data is put into msg and the remaining number of bytes to be read is returned. The message passed in will be appended to, so in the case where a read would have blocked, the Message can be passed to readAll() again when more data becomes available. Parameters: msg  Buffer for the message data length  Number of bytes to read, or 0 if unknown Returns: Number of bytes left to read in this message Exceptions: QSESocketBaseSocketClosed  The socket is closed. QSESocketBaseMessageTooLong  The incoming message has a length field greater than 4GB. QSESocketBaseMessageTooShort  The buffer read from the socket is not long enough to contain any data. QSESocketBaseReadFailed  select(2) returned an error or readFrom() threw it. Definition at line 119 of file Socket.cc. References isset_fd(), readFrom(), and set_fd(). Referenced by CODEX_Quorum::RemoteServer::receiveFrom().

size_t SocketBase::readFrom (  void *  output, size_t  maxSize = 1024 )  const [virtual]

Read data from a socket. Parameters: output  array containing the data returned from the socket maxSize  maximum number of bytes to be read from the socket Returns: number of bytes actually read (0=connection is closed) Exceptions: QSESocketBaseReadFailed  An error occurred while reading. Reimplemented in CODEX_Quorum::LoopbackSocket, and CODEX_SSL::SSLSocket. Definition at line 103 of file Socket.cc. Referenced by CODEX_Quorum::EchoServer::processRequest(), and readAll().

int SocketBase::set_fd (  fd_set *  fd_bitmap, StateType  s )  const [virtual]

Fill file descriptor bitmap. Parameters: fd_bitmap  bitmap of file descriptors to modify. The bit corresponding to the socket file descriptor will be set to 1. s  state of the socket to be tested. This allows derived classes to manipulate the bitmap appropriately when there is additional socket state to consider. Returns: file descriptor of the socket Definition at line 235 of file Socket.cc. Referenced by isset_fd(), CODEX_Quorum::EchoServer::processRequest(), readAll(), CODEX_SSL::SSLSocket::set_fd(), CODEX_Quorum::RemoteServer::set_fd(), and CODEX_Quorum::LocalServer::set_fd().

void SocketBase::setup (  struct sockaddr *  my_addr, socklen_t  addrlen, int  backlog )  [virtual]

This version of SocketBase::setup() allows for other varieties of sockets aside from IPv4. The arguments provided conform to the arguments of bind(2) and listen(2). Reimplemented in CODEX_Quorum::LoopbackSocket. Definition at line 79 of file Socket.cc. References protected_bind(), and protected_listen().

void SocketBase::setup (  int  port, int  backlog )  [virtual]

This version of SocketBase::setup() assumes an IPv4 socket. It will use AF_INET and INADDR_ANY when bind(2)ing. Protected member functions SocketBase::protected_bind() and SocketBase::protected_listen() are used for configuration, so that derived classes may reimplement them. Parameters: port  Local port on which to bind. backlog  Maximum number of pending connections in the queue. Exceptions: QSESocketBaseCannotBind  if the call to bind(2) fails. QSESocketBaseListenFailed  if the call to listen(2) fails. Reimplemented in CODEX_Quorum::LoopbackSocket. Definition at line 72 of file Socket.cc. References protected_bind(), and protected_listen(). Referenced by CODEX_Quorum::LocalServer::enable().

void SocketBase::writeTo (  const Message &  input  )  const [virtual]

Write data to a socket. Parameters: input  Message to queue for writing. Exceptions: QSESocketBaseWriteFailed  An error occurred while writing. Definition at line 212 of file Socket.cc. References CODEX_Quorum::Message::fill(), and m_msgQueue. Referenced by CODEX_Quorum::EchoServer::processRequest(), and CODEX_Quorum::RemoteServer::sendTo().

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

• Socket.h
• Socket.cc

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