This is a channel that operates indirectly through another channel(s). More...

#include <indchan.h>

Inheritance diagram for PIndirectChannel:

Collaboration diagram for PIndirectChannel:

Public Member Functions
Construction
	PIndirectChannel ()
	Create a new indirect channel without any channels to redirect to. More...

	~PIndirectChannel ()
	Close the indirect channel, deleting read/write channels if desired. More...

Overrides from class PObject
Comparison	Compare (const PObject &obj) const
	Determine if the two objects refer to the same indirect channel. More...

Overrides from class PChannel
virtual PString	GetName () const
	Get the name of the channel. More...

virtual P_INT_PTR	GetHandle () const
	Get the OS specific handle for the PSoundChannel. More...

virtual PBoolean	Close ()
	Close the channel. More...

virtual PBoolean	IsOpen () const
	Determine if the channel is currently open and read and write operations can be executed on it. More...

virtual PBoolean	Read (void *buf, PINDEX len)
	Low level read from the channel. More...

virtual int	ReadChar ()
	Read a single character from the channel. More...

virtual PBoolean	Write (const void *buf, PINDEX len)
	Low level write to the channel. More...

virtual PBoolean	Shutdown (ShutdownValue option)
	Close one or both of the data streams associated with a channel. More...

virtual bool	SetLocalEcho (bool localEcho)
	Set local echo mode. More...

virtual PChannel *	GetBaseReadChannel () const
	This function returns the eventual base channel for reading of a series of indirect channels provided by descendents of `PIndirectChannel`. More...

virtual PChannel *	GetBaseWriteChannel () const
	This function returns the eventual base channel for writing of a series of indirect channels provided by descendents of `PIndirectChannel`. More...

virtual PString	GetErrorText (ErrorGroup group=NumErrorGroups) const
	Get error message description. More...

Channel establish functions
PBoolean	Open (PChannel &channel)
	Set the channel for both read and write operations. More...

PBoolean	Open (PChannel *channel, PBoolean autoDelete=true)
	Set the channel for both read and write operations. More...

PBoolean	Open (PChannel readChannel, PChannel writeChannel, PBoolean autoDeleteRead=true, PBoolean autoDeleteWrite=true)
	Set the channel for both read and write operations. More...

PChannel *	Detach (ShutdownValue option=ShutdownReadAndWrite)
	Detach without closing the read/write channel. More...

PChannel *	GetReadChannel () const
	Get the channel used for read operations. More...

bool	SetReadChannel (PChannel *channel, bool autoDelete=true, bool closeExisting=false)
	Set the channel for read operations. More...

PChannel *	GetWriteChannel () const
	Get the channel used for write operations. More...

PBoolean	SetWriteChannel (PChannel *channel, bool autoDelete=true, bool closeExisting=false)
	Set the channel for read operations. More...

Public Member Functions inherited from PChannel
PBoolean	SetErrorValues (Errors errorCode, int osError, ErrorGroup group=LastGeneralError)
	Set error values to those specified. More...

virtual PINDEX	HashFunction () const
	Calculate a hash value for use in sets and dictionaries. More...

FILE *	FDOpen (const char *mode)
	Re-open the device using the stdio library. More...

void	SetReadTimeout (const PTimeInterval &time)
	Set the timeout for read operations. More...

PTimeInterval	GetReadTimeout () const
	Get the timeout for read operations. More...

PINDEX	GetLastReadCount () const
	Get the number of bytes read by the last Read() call. More...

PBoolean	ReadBlock (void *buf, PINDEX len)
	Read len bytes into the buffer from the channel. More...

PString	ReadString (PINDEX len)
	Read `len` character into a string from the channel. More...

void	SetWriteTimeout (const PTimeInterval &time)
	Set the timeout for write operations to complete. More...

PTimeInterval	GetWriteTimeout () const
	Get the timeout for write operations to complete. More...

virtual PBoolean	Write (const void buf, PINDEX len, const void )
	Low level write to the channel with marker. More...

virtual PINDEX	GetLastWriteCount () const
	Get the number of bytes written by the last Write() call. More...

PBoolean	WriteChar (int c)
	Write a single character to the channel. More...

PBoolean	WriteString (const PString &str)
	Write a string to the channel. More...

	~PChannel ()
	Close down the channel. More...

Errors	GetErrorCode (ErrorGroup group=NumErrorGroups) const
	Get normalised error code. More...

int	GetErrorNumber (ErrorGroup group=NumErrorGroups) const
	Get OS errro code. More...

virtual bool	ReadAsync (AsyncContext &context)
	Begin an asynchronous read from channel. More...

virtual void	OnReadComplete (AsyncContext &context)
	User callback function for when a `ReadAsync()` call has completed or timed out. More...

virtual bool	WriteAsync (AsyncContext &context)
	Begin an asynchronous write from channel. More...

virtual void	OnWriteComplete (AsyncContext &context)
	User callback function for when a WriteAsync() call has completed or timed out. More...

virtual bool	FlowControl (const void *flowData)
	Flow Control information Pass data to the channel for flowControl determination. More...

PBoolean	SetBufferSize (PINDEX newSize)
	Set the iostream buffer size for reads and writes. More...

PBoolean	SendCommandString (const PString &command)
	Send a command meta-string. More...

void	AbortCommandString ()
	Abort a command string that is in progress. More...

Public Member Functions inherited from PObject
unsigned	GetTraceContextIdentifier () const
	Get PTRACE context identifier. More...

void	SetTraceContextIdentifier (unsigned id)

void	GetTraceContextIdentifier (PObject &obj)

void	GetTraceContextIdentifier (PObject *obj)

void	SetTraceContextIdentifier (const PObject &obj)

void	SetTraceContextIdentifier (const PObject *obj)

virtual	~PObject ()

virtual PObject *	Clone () const
	Create a copy of the class on the heap. More...

template<class CLS >
CLS *	CloneAs () const
	As for Clone() but converts to specified type. More...

virtual Comparison	CompareObjectMemoryDirect (const PObject &obj) const
	Determine the byte wise comparison of two objects. More...

bool	operator== (const PObject &obj) const
	Compare the two objects. More...

bool	operator!= (const PObject &obj) const
	Compare the two objects. More...

bool	operator< (const PObject &obj) const
	Compare the two objects. More...

bool	operator> (const PObject &obj) const
	Compare the two objects. More...

bool	operator<= (const PObject &obj) const
	Compare the two objects. More...

bool	operator>= (const PObject &obj) const
	Compare the two objects. More...

virtual const char *	GetClass (unsigned ancestor=0) const
	Get the current dynamic type of the object instance. More...

PBoolean	IsClass (const char *cls) const

virtual PBoolean	InternalIsDescendant (const char *clsName) const
	Determine if the dynamic type of the current instance is a descendent of the specified class. More...

__inline const PObject *	PTraceObjectInstance () const

virtual void	PrintOn (ostream &strm) const
	Output the contents of the object to the stream. More...

virtual void	ReadFrom (istream &strm)
	Input the contents of the object from the stream. More...

Protected Member Functions
virtual PBoolean	OnOpen ()
	This callback is executed when the Open() function is called with open channels. More...

Protected Member Functions inherited from PChannel
	PChannel (const PChannel &)

PChannel &	operator= (const PChannel &)

virtual PBoolean	ConvertOSError (P_INT_PTR libcReturnValue, ErrorGroup group=LastGeneralError)
	Convert an operating system error into platform independent error. More...

int	ReadCharWithTimeout (PTimeInterval &timeout)
	Read a character with specified timeout. More...

PBoolean	ReceiveCommandString (int nextChar, const PString &reply, PINDEX &pos, PINDEX start)

virtual int	os_errno () const

PBoolean	PXSetIOBlock (PXBlockType type, const PTimeInterval &timeout)

P_INT_PTR	GetOSHandleAsInt () const

int	PXClose ()

	PChannel ()
	Create the channel. More...

Protected Member Functions inherited from PObject
	PObject ()
	Constructor for PObject, made protected so cannot ever create one on its own. More...

Protected Attributes
PChannel *	readChannel
	Channel for read operations. More...

PBoolean	readAutoDelete
	Automatically delete read channel on destruction. More...

PChannel *	writeChannel
	Channel for write operations. More...

PBoolean	writeAutoDelete
	Automatically delete write channel on destruction. More...

PReadWriteMutex	channelPointerMutex
	Race condition prevention on closing channel. More...

Protected Attributes inherited from PChannel
P_INT_PTR	os_handle
	The operating system file handle return by standard open() function. More...

Errors	lastErrorCode [NumErrorGroups+1]
	The platform independant error code. More...

int	lastErrorNumber [NumErrorGroups+1]
	The operating system error number (eg as returned by errno). More...

PINDEX	lastReadCount
	Number of byte last read by the Read() function. More...

PINDEX	lastWriteCount
	Number of byte last written by the Write() function. More...

PTimeInterval	readTimeout
	Timeout for read operations. More...

PTimeInterval	writeTimeout
	Timeout for write operations. More...

PString	channelName
	Name of channel. More...

PMutex	px_threadMutex

PXBlockType	px_lastBlockType

PThread *	px_readThread

PThread *	px_writeThread

PMutex	px_writeMutex

PThread *	px_selectThread [3]

PMutex	px_selectMutex [3]

Protected Attributes inherited from PObject
unsigned	m_traceContextIdentifier

Additional Inherited Members
Public Types inherited from PChannel
enum	PXBlockType { PXReadBlock, PXWriteBlock, PXAcceptBlock, PXConnectBlock }

enum	Errors { NoError, NotFound, FileExists, DiskFull, AccessDenied, DeviceInUse, BadParameter, NoMemory, NotOpen, Timeout, Interrupted, BufferTooSmall, Miscellaneous, ProtocolFailure, Unavailable, NumNormalisedErrors }
	Normalised error codes. More...

enum	ErrorGroup { LastReadError, LastWriteError, LastGeneralError, NumErrorGroups }
	Error groups. More...

typedef PNotifierTemplate < PChannel::AsyncContext & >	AsyncNotifier

enum	ShutdownValue { ShutdownRead = 0, ShutdownWrite = 1, ShutdownReadAndWrite = 2 }

Static Public Member Functions inherited from PChannel
static PString	GetErrorText (Errors lastError, int osError=0)
	Get error message description. More...

Static Public Member Functions inherited from PObject
static Comparison	InternalCompareObjectMemoryDirect (const PObject obj1, const PObject obj2, PINDEX size)
	Internal function caled from CompareObjectMemoryDirect() More...

static const char *	Class ()
	Get the name of the class as a C string. More...

static __inline const PObject *	PTraceObjectInstance (const char *)

static __inline const PObject *	PTraceObjectInstance (const PObject *obj)

Friends inherited from PObject

Detailed Description

This is a channel that operates indirectly through another channel(s).

This allows for a protocol to operate through a "channel" mechanism and for its low level byte exchange (Read and Write) to operate via a completely different channel, eg TCP or Serial port etc.

Constructor & Destructor Documentation

PIndirectChannel::PIndirectChannel ( )

Create a new indirect channel without any channels to redirect to.

If an attempt to read or write is made before Open() is called the the functions will assert.

PIndirectChannel::~PIndirectChannel ( )

Close the indirect channel, deleting read/write channels if desired.

Member Function Documentation

virtual PBoolean PIndirectChannel::Close ( )

virtual

Close the channel.

This will detach itself from the read and write channels and delete both of them if they are auto delete.

Returns: true if the channel is closed.

Reimplemented from PChannel.

Reimplemented in PRFC822Channel, PSSLChannel, PVXMLChannel, PPOP3Client, PVXMLSession, XMPP::Stream, XMPP::Transport, PSMTPClient, PFTPClient, PSSDP, XMPP::C2S::TCPTransport, and PSoundChannelPortAudio.

Comparison PIndirectChannel::Compare ( const PObject & obj ) const

virtual

Determine if the two objects refer to the same indirect channel.

This actually compares the channel pointers.

Returns: EqualTo if channel pointer identical.

Parameters

obj	Another indirect channel to compare against.

Reimplemented from PChannel.

PChannel* PIndirectChannel::Detach ( ShutdownValue option = ShutdownReadAndWrite )

Detach without closing the read/write channel.

If option is ShutdownReadAndWrite and the read and write channels are different, then the channels are not detached and NULL is returned.

Returns: Channel being detached.

Parameters

option Flag for detach of read, write or both.

virtual PChannel* PIndirectChannel::GetBaseReadChannel ( ) const

virtual

This function returns the eventual base channel for reading of a series of indirect channels provided by descendents of PIndirectChannel.

The behaviour for this function is to return "this".

Returns: Pointer to base I/O channel for the indirect channel.

Reimplemented from PChannel.

virtual PChannel* PIndirectChannel::GetBaseWriteChannel ( ) const

virtual

This function returns the eventual base channel for writing of a series of indirect channels provided by descendents of PIndirectChannel.

The behaviour for this function is to return "this".

Returns: Pointer to base I/O channel for the indirect channel.

Reimplemented from PChannel.

virtual PString PIndirectChannel::GetErrorText ( ErrorGroup group = NumErrorGroups ) const

virtual

Get error message description.

Return a string indicating the error message that may be displayed to the user. The error for the last I/O operation in this object is used.

Returns: Operating System error description string.

Parameters

group Error group to get

Reimplemented from PChannel.

Reimplemented in PSSLChannel, and PSoundChannelPortAudio.

virtual P_INT_PTR PIndirectChannel::GetHandle ( ) const

virtual

Get the OS specific handle for the PSoundChannel.

Returns: integer value of the handle.

Reimplemented from PChannel.

virtual PString PIndirectChannel::GetName ( ) const

virtual

Get the name of the channel.

This is a combination of the channel pointers names (or simply the channel pointers name if the read and write channels are the same) or empty string if both null.

Returns: string for the channel names.

Reimplemented from PChannel.

Reimplemented in PSoundChannelPortAudio.

PChannel* PIndirectChannel::GetReadChannel ( ) const

Get the channel used for read operations.

Returns: pointer to the read channel.

PChannel* PIndirectChannel::GetWriteChannel ( ) const

Get the channel used for write operations.

Returns: pointer to the write channel.

virtual PBoolean PIndirectChannel::IsOpen ( ) const

virtual

Determine if the channel is currently open and read and write operations can be executed on it.

For example, in the PFile class it returns if the file is currently open.

Returns: true if the channel is open.

Reimplemented from PChannel.

Reimplemented in PVXMLChannel, and PSoundChannelPortAudio.

virtual PBoolean PIndirectChannel::OnOpen ( )

protectedvirtual

This callback is executed when the Open() function is called with open channels.

It may be used by descendent channels to do any handshaking required by the protocol that channel embodies.

The default behaviour is to simply return true.

Returns: Returns true if the protocol handshaking is successful.

Reimplemented in PRFC822Channel, PSSLChannel, PPOP3Server, PPOP3Client, PFTPServer, PSMTPServer, PFTPClient, PSMTPClient, and XMPP::Stream.

PBoolean PIndirectChannel::Open ( PChannel & channel )

Set the channel for both read and write operations.

This then checks that they are open and then calls the OnOpen() virtual function. If it in turn returns true then the Open() function returns success.

Returns: true if both channels are set, open and OnOpen() returns true.

Parameters

channel Channel to be used for both read and write operations.

PBoolean PIndirectChannel::Open	(	PChannel *	channel,
		PBoolean	autoDelete = `true`
	)

Set the channel for both read and write operations.

This then checks that they are open and then calls the OnOpen() virtual function. If it in turn returns true then the Open() function returns success.

The channel pointed to by channel may be automatically deleted when the PIndirectChannel is destroyed or a new subchannel opened.

Returns: true if both channels are set, open and OnOpen() returns true.

Parameters

channel	Channel to be used for both read and write operations.
autoDelete	Automatically delete the channel

PBoolean PIndirectChannel::Open	(	PChannel *	readChannel,
		PChannel *	writeChannel,
		PBoolean	autoDeleteRead = `true`,
		PBoolean	autoDeleteWrite = `true`
	)

Set the channel for both read and write operations.

This then checks that they are open and then calls the OnOpen() virtual function. If it in turn returns true then the Open() function returns success.

The channels pointed to by readChannel and writeChannel may be automatically deleted when the PIndirectChannel is destroyed or a new subchannel opened.

Returns: true if both channels are set, open and OnOpen() returns true.

Parameters

readChannel	Channel to be used for both read operations.
writeChannel	Channel to be used for both write operations.
autoDeleteRead	Automatically delete the read channel
autoDeleteWrite	Automatically delete the write channel

virtual PBoolean PIndirectChannel::Read	(	void *	buf,
		PINDEX	len
	)

virtual

Low level read from the channel.

This function may block until the requested number of characters were read or the read timeout was reached. The GetLastReadCount() function returns the actual number of bytes read.

This will use the readChannel pointer to actually do the read. If readChannel is null the this asserts.

The GetErrorCode() function should be consulted after Read() returns false to determine what caused the failure.

Returns: true indicates that at least one character was read from the channel. false means no bytes were read due to timeout or some other I/O error.

Parameters

buf	Pointer to a block of memory to receive the read bytes.
len	Maximum number of bytes to read into the buffer.

Reimplemented from PChannel.

Reimplemented in PSSLChannel, PVXMLChannel, PDelayChannel, PInternetProtocol, and PSoundChannelPortAudio.

virtual int PIndirectChannel::ReadChar ( )

virtual

Read a single character from the channel.

If one was not available within the read timeout period, or an I/O error occurred, then the function gives with a -1 return value.

Note, normally the character read will be an 8 bit value, but for some derived classes, e.g. PConsoleChannel, this may be a code for special input.

Returns: byte read or -1 if no character could be read.

Reimplemented from PChannel.

Reimplemented in PInternetProtocol.

virtual bool PIndirectChannel::SetLocalEcho ( bool localEcho )

virtual

Set local echo mode.

For some classes of channel, e.g. PConsoleChannel, data read by this channel is automatically echoed. This disables the function so things like password entry can work.

Default behaviour does nothing and return true if the channel is open.

Reimplemented from PChannel.

bool PIndirectChannel::SetReadChannel	(	PChannel *	channel,
		bool	autoDelete = `true`,
		bool	closeExisting = `false`
	)

Set the channel for read operations.

Returns: Returns true if both channels are set and are both open.

Parameters

channel	Channel to be used for both read operations.
autoDelete	Automatically delete the channel
closeExisting	Close (and auto-delete) the existing read channel

PBoolean PIndirectChannel::SetWriteChannel	(	PChannel *	channel,
		bool	autoDelete = `true`,
		bool	closeExisting = `false`
	)

Set the channel for read operations.

Returns: Returns true if both channels are set and are both open.

Parameters

channel	Channel to be used for both read operations.
autoDelete	Automatically delete the channel
closeExisting	Close (and auto-delete) the existing read channel

virtual PBoolean PIndirectChannel::Shutdown ( ShutdownValue option )

virtual

Close one or both of the data streams associated with a channel.

The behavour here is to pass the shutdown on to its read and write channels.

Returns: true if the shutdown was successfully performed.

Parameters

option Flag for shut down of read, write or both.

Reimplemented from PChannel.

Reimplemented in PSSLChannel.

virtual PBoolean PIndirectChannel::Write	(	const void *	buf,
		PINDEX	len
	)

virtual

Low level write to the channel.

This function will block until the requested number of characters are written or the write timeout is reached. The GetLastWriteCount() function returns the actual number of bytes written.

This will use the writeChannel pointer to actually do the write. If writeChannel is null the this asserts.

The GetErrorCode() function should be consulted after Write() returns false to determine what caused the failure.

Returns: true if at least len bytes were written to the channel.

Parameters

buf	Pointer to a block of memory to write.
len	Number of bytes to write.

Reimplemented from PChannel.

Reimplemented in PRFC822Channel, PSSLChannel, PVXMLChannel, PDelayChannel, XMPP::Stream, PInternetProtocol, and PSoundChannelPortAudio.

Member Data Documentation

PReadWriteMutex PIndirectChannel::channelPointerMutex

protected

Race condition prevention on closing channel.

PBoolean PIndirectChannel::readAutoDelete

protected

Automatically delete read channel on destruction.

PChannel* PIndirectChannel::readChannel

protected

Channel for read operations.

Referenced by PSoundChannel::GetSoundChannel(), and PVXMLSession::GetVXMLChannel().

PBoolean PIndirectChannel::writeAutoDelete

protected

Automatically delete write channel on destruction.

PChannel* PIndirectChannel::writeChannel

protected

Channel for write operations.

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

indchan.h

Public Member Functions

Protected Member Functions

Protected Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation