CODEX_Quorum::LoopbackSocket Class Reference

This class implements a loopback socket. More...

#include <LoopbackSocket.h>

Inheritance diagram for CODEX_Quorum::LoopbackSocket:

[legend]Collaboration diagram for CODEX_Quorum::LoopbackSocket:

[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

LoopbackSocket ()

Constructor for loopback sockets.

LoopbackSocket (const LoopbackSocket &aOther)

Copy constructor.

virtual ~LoopbackSocket ()

Destructor.

void setup (int port, int backlog)

Dummy function.

void setup (struct sockaddr *my_addr, socklen_t addrlen, int backlog)

Dummy function.

void connect (const RemoteServer &server)

Dummy function.

SocketBase * accept ()

Accept is meaningless for this type of socket.

size_t readFrom (void *output, size_t maxSize=1024) const

Uses internal buffer.

int set_fd (fd_set *fd_bitmap, StateType s) const

Fill file descriptor bitmap.

bool isset_fd (const fd_set *fd_bitmap, StateType s) const

Check file descriptor bitmap.

void flush () const

Force a blocking write of the internal buffer.

Socket I/O

These functions handle basic socket I/O.

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.

Protected Member Functions

SocketBase * clone ()

Clone the current socket.

virtual int internal_write (const unsigned char *output, size_t maxSize) const

Write data to the socket.

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.

Detailed Description

This class implements a loopback socket.

The LoopbackSocket is essentially just a buffer, but it behaves like a socket from the perspective of the I/O abstraction.

Definition at line 36 of file LoopbackSocket.h.

Member Function Documentation

SocketBase* CODEX_Quorum::LoopbackSocket::clone ( ) [inline, protected, virtual]

Clone the current socket.
This is a largely meaningless operation, since LoopbackSocket connects back to itself. Consequently, we just return the socket itself. Given that clone() is typically only used in accept, this shouldn't even get called.
Reimplemented from CODEX_Quorum::SocketBase.
Definition at line 102 of file LoopbackSocket.h.
Referenced by accept().

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

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 CODEX_Quorum::SocketBase::protected_accept().

void LoopbackSocket::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 from CODEX_Quorum::SocketBase.
Definition at line 94 of file LoopbackSocket.cc.
References CODEX_Quorum::Message::buffer().

int SocketBase::internal_write ( const unsigned char * output,

size_t maxSize

) const [protected, virtual, inherited]

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 CODEX_Quorum::SocketBase::flush(), and CODEX_Quorum::SocketBase::isset_fd().

bool SocketBase::isset_fd ( const fd_set * fd_bitmap,

StateType s

) const [virtual, inherited]

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(), CODEX_Quorum::SocketBase::internal_write(), CODEX_Quorum::Message::length(), CODEX_Quorum::SocketBase::m_msgOffset, CODEX_Quorum::SocketBase::m_msgQueue, and CODEX_Quorum::SocketBase::set_fd().
Referenced by CODEX_SSL::SSLSocket::isset_fd(), CODEX_Quorum::RemoteServer::isset_fd(), CODEX_Quorum::LocalServer::isset_fd(), CODEX_Quorum::EchoServer::processRequest(), and CODEX_Quorum::SocketBase::readAll().

bool LoopbackSocket::isset_fd ( const fd_set * fd_bitmap,

StateType s

) const

Check file descriptor bitmap.
As there is no file descriptor, the output of select(2) is irrelevant for this socket. What matters is whether there is information in the read buffer. Testing write is always going to be successful.
Definition at line 66 of file LoopbackSocket.cc.
References CODEX_Quorum::Message::buffer().

void SocketBase::protected_bind ( struct sockaddr * my_addr,

socklen_t addrlen

) [protected, virtual, inherited]

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 CODEX_Quorum::SocketBase::setup().

size_t SocketBase::readAll ( Message & msg,

size_t length = 0

) const [virtual, inherited]

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 CODEX_Quorum::SocketBase::isset_fd(), CODEX_Quorum::SocketBase::readFrom(), and CODEX_Quorum::SocketBase::set_fd().
Referenced by CODEX_Quorum::RemoteServer::receiveFrom().

int SocketBase::set_fd ( fd_set * fd_bitmap,

StateType s

) const [virtual, inherited]

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 CODEX_Quorum::SocketBase::isset_fd(), CODEX_Quorum::EchoServer::processRequest(), CODEX_Quorum::SocketBase::readAll(), CODEX_SSL::SSLSocket::set_fd(), CODEX_Quorum::RemoteServer::set_fd(), and CODEX_Quorum::LocalServer::set_fd().

int CODEX_Quorum::LoopbackSocket::set_fd ( fd_set * fd_bitmap,

StateType s

) const [inline]

Fill file descriptor bitmap.
This is a dummy routine. Since there isn't a real socket, there's no file descriptor.
Definition at line 79 of file LoopbackSocket.h.

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

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 CODEX_Quorum::SocketBase::m_msgQueue.
Referenced by CODEX_Quorum::EchoServer::processRequest(), and CODEX_Quorum::RemoteServer::sendTo().

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

Generated on Fri May 6 17:42:29 2005 for COrnell Data EXchange (CODEX) by

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