YARP
Yet Another Robot Platform
yarp::os::Port Class Reference

A mini-server for network communication. More...

#include <yarp/os/Port.h>

+ Inheritance diagram for yarp::os::Port:

Detailed Description

A mini-server for network communication.

It maintains a dynamic collection of incoming and outgoing connections. Data coming from any incoming connection can be received by calling Port::read. Calls to Port::write result in data being sent to all the outgoing connections.

Communication with Port objects is blocking by default, this means that YARP will not drop messages and timing between readers and senders will be coupled (notice that messages may still get dropped in the network if you use an unreliable protocol like UDP).

See also
For help sending and receiving data in the background and decouple timing, see BufferedPort, or PortReaderBuffer and PortWriterBuffer.

For examples and help, see:

Examples:
os/database.cpp, os/image_process_module.cpp, os/portable_pair.cpp, os/simple_receiver.cpp, os/simple_sender.cpp, port_power/ex0000_receiver.cpp, port_power/ex0001_sender.cpp, port_power/ex0300_port_callback.cpp, port_power/ex0400_expect_reply.cpp, port_power/ex0401_give_reply.cpp, port_power/ex0402_port_callback_reply.cpp, port_power/ex0500_raw_target_receiver.cpp, port_power/ex0501_raw_target_sender.cpp, port_power/ex0503_serial_target_receiver.cpp, port_power/ex0504_serial_target_sender.cpp, port_power/ex0505_compliant_target_receiver.cpp, port_power/ex0506_compliant_target_sender.cpp, port_power/ex0507_alternative_compliant_target_receiver.cpp, port_power/ex0508_alternative_compliant_target_sender.cpp, and portaudio/sound_sender_mic.cpp.

Definition at line 49 of file Port.h.

Public Member Functions

 Port ()
 Constructor. More...
 
virtual ~Port ()
 Destructor. More...
 
bool open (const std::string &name) override
 Start port operation, with a specific name, with automatically-chosen network parameters. More...
 
bool open (const Contact &contact, bool registerName=true) override
 Start port operation with user-chosen network parameters. More...
 
bool sharedOpen (Port &port)
 Open a port wrapping an existing port. More...
 
bool openFake (const std::string &name)
 Start port without making it accessible from the network. More...
 
bool addOutput (const std::string &name) override
 Add an output connection to the specified port. More...
 
bool addOutput (const std::string &name, const std::string &carrier) override
 Add an output connection to the specified port, using a specified carrier. More...
 
bool addOutput (const Contact &contact) override
 Add an output connection to the specified port, using specified network parameters. More...
 
void close () override
 Stop port activity. More...
 
virtual void interrupt () override
 Interrupt any current reads or writes attached to the port. More...
 
virtual void resume () override
 Put the port back in an operative state after interrupt() has been called. More...
 
Contact where () const override
 Returns information about how this port can be reached. More...
 
bool write (const PortWriter &writer, const PortWriter *callback=nullptr) const override
 Write an object to the port. More...
 
bool write (const PortWriter &writer, PortReader &reader, const PortWriter *callback=nullptr) const override
 Write an object to the port, then expect one back. More...
 
bool read (PortReader &reader, bool willReply=false) override
 Read an object from the port. More...
 
bool reply (PortWriter &writer) override
 Send an object as a reply to an object read from the port. More...
 
bool replyAndDrop (PortWriter &writer) override
 Same as reply(), but closes connection after reply. More...
 
void setReader (PortReader &reader) override
 Set an external reader for port data. More...
 
virtual void setAdminReader (PortReader &reader) override
 Set an external reader for unrecognized administrative port messages. More...
 
void setReaderCreator (PortReaderCreator &creator)
 Set a creator for readers for port data. More...
 
void enableBackgroundWrite (bool backgroundFlag)
 control whether writing from this port is done in the background. More...
 
bool isWriting () override
 Report whether the port is currently writing data. More...
 
virtual bool setEnvelope (PortWriter &envelope) override
 Set an envelope (e.g., a timestamp) to the next message which will be sent. More...
 
virtual bool getEnvelope (PortReader &envelope) override
 Get the envelope information (e.g., a timestamp) from the last message received on the port. More...
 
virtual int getInputCount () override
 Determine how many connections are arriving into this port. More...
 
virtual int getOutputCount () override
 Determine how many output connections this port has. More...
 
virtual void getReport (PortReport &reporter) override
 Get information on the state of the port - connections etc. More...
 
virtual void setReporter (PortReport &reporter) override
 Set a callback to be called upon any future connections and disconnections to/from the port. More...
 
virtual void resetReporter () override
 Remove the callback which is called upon any future connections and disconnections to/from the port. More...
 
void setAdminMode (bool adminMode=true)
 Turn on/off "admin" mode. More...
 
void setInputMode (bool expectInput) override
 Configure the port to allow or forbid inputs. More...
 
void setOutputMode (bool expectOutput) override
 Configure the port to allow or forbid outputs. More...
 
void setRpcMode (bool expectRpc) override
 Configure the port to be RPC only. More...
 
bool setTimeout (float timeout)
 Set a timeout on network operations. More...
 
void setVerbosity (int level)
 Set whether the port should issue messages about its operations. More...
 
int getVerbosity ()
 Get port verbosity level. More...
 
virtual Type getType () override
 Get the type of data the port has committed to send/receive. More...
 
virtual void promiseType (const Type &typ) override
 Commit the port to a particular type of data. More...
 
virtual PropertyacquireProperties (bool readOnly) override
 Access unstructured port properties. More...
 
virtual void releaseProperties (Property *prop) override
 End access unstructured port properties. More...
 
virtual void includeNodeInName (bool flag) override
 Choose whether to prepend a node name (if one is available) to the port's name. More...
 
bool isOpen () const
 Check if the port has been opened. More...
 
virtual bool setCallbackLock (yarp::os::Mutex *mutex=nullptr) override
 Add a lock to use when invoking callbacks. More...
 
virtual bool removeCallbackLock () override
 Remove a lock on callbacks added with setCallbackLock() More...
 
virtual bool lockCallback () override
 Lock callbacks until unlockCallback() is called. More...
 
virtual bool tryLockCallback () override
 Try to lock callbacks until unlockCallback() is called. More...
 
virtual void unlockCallback () override
 Unlock callbacks. More...
 
- Public Member Functions inherited from yarp::os::Contactable
virtual ~Contactable ()
 Destructor. More...
 
virtual std::string getName () const
 Get name of port. More...
 
void setReadOnly ()
 Shorthand for setInputMode(true), setOutputMode(false), setRpcMode(false) More...
 
void setWriteOnly ()
 Shorthand for setInputMode(false), setOutputMode(true), setRpcMode(false) More...
 
void setRpcServer ()
 Shorthand for setInputMode(true), setOutputMode(false), setRpcMode(true) More...
 
void setRpcClient ()
 Shorthand for setInputMode(false), setOutputMode(true), setRpcMode(true) More...
 

Private Member Functions

void * needImplementation () const
 
bool open (const Contact &contact, bool registerName, const char *fakeName)
 

Private Attributes

void * implementation
 
bool owned
 

Constructor & Destructor Documentation

◆ Port()

Port::Port ( )

Constructor.

The port begins life in a dormant state. Call Port::open to start things happening.

Definition at line 45 of file Port.cpp.

◆ ~Port()

Port::~Port ( )
virtual

Destructor.

Definition at line 51 of file Port.cpp.

Member Function Documentation

◆ acquireProperties()

Property * Port::acquireProperties ( bool  readOnly)
overridevirtual

Access unstructured port properties.

Parameters
readOnlyset this if you won't be modifying the properties.
Returns
the port properties (or nullptr if readOnly and none have been set)

Implements yarp::os::Contactable.

Definition at line 656 of file Port.cpp.

◆ addOutput() [1/3]

bool Port::addOutput ( const std::string &  name)
overridevirtual

Add an output connection to the specified port.

Parameters
namethe name of the target port
Returns
true iff the connection is successfully created

Implements yarp::os::Contactable.

Definition at line 359 of file Port.cpp.

◆ addOutput() [2/3]

bool Port::addOutput ( const std::string &  name,
const std::string &  carrier 
)
overridevirtual

Add an output connection to the specified port, using a specified carrier.

Parameters
namethe name of the target port
carrierthe carrier (network protocol) to use, e.g. "tcp", "udp", "mcast", "text", ...
Returns
true iff the connection is successfully created

Implements yarp::os::Contactable.

Definition at line 364 of file Port.cpp.

◆ addOutput() [3/3]

bool Port::addOutput ( const Contact contact)
overridevirtual

Add an output connection to the specified port, using specified network parameters.

Parameters
contactinformation on how to reach the target
Returns
true iff the connection is successfully created

Implements yarp::os::Contactable.

Definition at line 416 of file Port.cpp.

◆ close()

void Port::close ( )
overridevirtual

Stop port activity.

Implements yarp::os::Contactable.

Examples:
os/simple_receiver.cpp, and os/simple_sender.cpp.

Definition at line 369 of file Port.cpp.

◆ enableBackgroundWrite()

void Port::enableBackgroundWrite ( bool  backgroundFlag)

control whether writing from this port is done in the background.

Parameters
backgroundFlagif true, calls to Port::write should return immediately

Definition at line 527 of file Port.cpp.

◆ getEnvelope()

bool Port::getEnvelope ( PortReader envelope)
overridevirtual

Get the envelope information (e.g., a timestamp) from the last message received on the port.

You must be sure to match the type of your envelope for getEnvelope with whatever is being sent using setEnvelope. The Stamp class is a typical choice for timestamps. The Bottle class also works as an envelope, but it is not specialized to be efficient.

Parameters
enveloperecipient for envelope information for last message received by port.
Returns
true iff reading the envelope was successful

Implements yarp::os::Contactable.

Definition at line 549 of file Port.cpp.

◆ getInputCount()

int Port::getInputCount ( )
overridevirtual

Determine how many connections are arriving into this port.

In other words, how many other ports have this port listed as an output?

Returns
number of input connections

Implements yarp::os::Contactable.

Definition at line 555 of file Port.cpp.

◆ getOutputCount()

int Port::getOutputCount ( )
overridevirtual

Determine how many output connections this port has.

Returns
number of output connections

Implements yarp::os::Contactable.

Definition at line 562 of file Port.cpp.

◆ getReport()

void Port::getReport ( PortReport reporter)
overridevirtual

Get information on the state of the port - connections etc.

PortReport::report will be called once for each connection to the port that exists right now. To request callbacks for any future connections/disconnections, use the setReporter method instead.

Parameters
reportercallback for port event/state information

Implements yarp::os::Contactable.

Definition at line 569 of file Port.cpp.

◆ getType()

Type Port::getType ( )
overridevirtual

Get the type of data the port has committed to send/receive.

Not all ports commit to a particular type of data.

Returns
type of data to expect/provide

Implements yarp::os::Contactable.

Definition at line 646 of file Port.cpp.

◆ getVerbosity()

int Port::getVerbosity ( )

Get port verbosity level.

Returns
port verbosity level.

Definition at line 641 of file Port.cpp.

◆ includeNodeInName()

void Port::includeNodeInName ( bool  flag)
overridevirtual

Choose whether to prepend a node name (if one is available) to the port's name.

Node names are set using yarp::os::Node.

Parameters
flagtrue if the node name should be added to port names

Implements yarp::os::Contactable.

Definition at line 666 of file Port.cpp.

◆ interrupt()

void Port::interrupt ( )
overridevirtual

Interrupt any current reads or writes attached to the port.

This is useful prior to calling close(), if there are multiple threads operating on the port. Any reads or writes after the call to interrupt() will fail - unless resume() is called.

Implements yarp::os::Contactable.

Definition at line 389 of file Port.cpp.

◆ isOpen()

bool Port::isOpen ( ) const

Check if the port has been opened.

Definition at line 671 of file Port.cpp.

◆ isWriting()

bool Port::isWriting ( )
overridevirtual

Report whether the port is currently writing data.

Returns
true iff the port is writing in the background.

Implements yarp::os::Contactable.

Definition at line 534 of file Port.cpp.

◆ lockCallback()

bool Port::lockCallback ( )
overridevirtual

Lock callbacks until unlockCallback() is called.

Has no effect if no lock has been set via a call to setCallbackLock(). Will block if callbacks are already locked.

Returns
true if callbacks were locked

Implements yarp::os::Contactable.

Definition at line 689 of file Port.cpp.

◆ needImplementation()

void * Port::needImplementation ( ) const
private

Definition at line 30 of file Port.cpp.

◆ open() [1/3]

◆ open() [2/3]

bool Port::open ( const Contact contact,
bool  registerName = true 
)
overridevirtual

Start port operation with user-chosen network parameters.

Contact information is supplied by the user rather than the name server. If the Contact information is incomplete, the name server is used to complete it (set registerName to false if you don't want name server help).

Returns
true iff the port started operation successfully and is now visible on the YARP network

Implements yarp::os::Contactable.

Definition at line 84 of file Port.cpp.

◆ open() [3/3]

bool Port::open ( const Contact contact,
bool  registerName,
const char *  fakeName 
)
private

Definition at line 89 of file Port.cpp.

◆ openFake()

bool Port::openFake ( const std::string &  name)

Start port without making it accessible from the network.

The port is unusable for many purposes, other than sending out data to specific outputs added with addOutput().

Parameters
namean arbitrary name that connections from this port will claim to be from.
Returns
true on success

Definition at line 74 of file Port.cpp.

◆ promiseType()

void Port::promiseType ( const Type typ)
overridevirtual

Commit the port to a particular type of data.

Parameters
typthe type of data the port will send/receive

Implements yarp::os::Contactable.

Definition at line 651 of file Port.cpp.

◆ read()

bool Port::read ( PortReader reader,
bool  willReply = false 
)
overridevirtual

Read an object from the port.

Parameters
readerany object that knows how to read itself from a network connection - see for example Bottle
willReplyyou must set this to true if you intend to call reply()
Returns
true iff the object is successfully read

Implements yarp::os::UnbufferedContactable.

Examples:
os/database.cpp, os/simple_receiver.cpp, port_power/ex0000_receiver.cpp, port_power/ex0401_give_reply.cpp, port_power/ex0500_raw_target_receiver.cpp, port_power/ex0503_serial_target_receiver.cpp, port_power/ex0505_compliant_target_receiver.cpp, and port_power/ex0507_alternative_compliant_target_receiver.cpp.

Definition at line 480 of file Port.cpp.

◆ releaseProperties()

void Port::releaseProperties ( Property prop)
overridevirtual

End access unstructured port properties.

Parameters
propthe port property object provided by acquireProperties()

Implements yarp::os::Contactable.

Definition at line 661 of file Port.cpp.

◆ removeCallbackLock()

bool Port::removeCallbackLock ( )
overridevirtual

Remove a lock on callbacks added with setCallbackLock()

Implements yarp::os::Contactable.

Definition at line 684 of file Port.cpp.

◆ reply()

bool Port::reply ( PortWriter writer)
overridevirtual

Send an object as a reply to an object read from the port.

Only call this method if you set the willReply flag to true when you called Port::read.

Parameters
writerany object that knows how to write itself to a network connection - see for example Bottle
Returns
true iff the object is successfully written

Implements yarp::os::UnbufferedContactable.

Examples:
os/database.cpp, and port_power/ex0401_give_reply.cpp.

Definition at line 492 of file Port.cpp.

◆ replyAndDrop()

bool Port::replyAndDrop ( PortWriter writer)
overridevirtual

Same as reply(), but closes connection after reply.

This is useful for interoperation with XML/RPC clients that do not expect to reuse a connection.

Parameters
writerany object that knows how to write itself to a network connection - see for example Bottle
Returns
true iff the object is successfully written

Implements yarp::os::UnbufferedContactable.

Definition at line 498 of file Port.cpp.

◆ resetReporter()

void Port::resetReporter ( )
overridevirtual

Remove the callback which is called upon any future connections and disconnections to/from the port.

Implements yarp::os::Contactable.

Definition at line 583 of file Port.cpp.

◆ resume()

void Port::resume ( )
overridevirtual

Put the port back in an operative state after interrupt() has been called.

Implements yarp::os::Contactable.

Definition at line 398 of file Port.cpp.

◆ setAdminMode()

void Port::setAdminMode ( bool  adminMode = true)

Turn on/off "admin" mode.

With admin mode on, messages received from this port will be treated by other ports as administrative messages, rather than as data to pass on to the owner of the port.

Parameters
adminModeadministration flag

Definition at line 590 of file Port.cpp.

◆ setAdminReader()

void Port::setAdminReader ( PortReader reader)
overridevirtual

Set an external reader for unrecognized administrative port messages.

Parameters
readerthe external reader to use

Implements yarp::os::Contactable.

Definition at line 512 of file Port.cpp.

◆ setCallbackLock()

bool Port::setCallbackLock ( yarp::os::Mutex mutex = nullptr)
overridevirtual

Add a lock to use when invoking callbacks.

mutex.lock() will be called before and mutex.unlock() will be called after the callback. This applies at least to callbacks set by setReader and setAdminReader, and in future may apply to other callbacks.

Parameters
mutexthe lock to use. If nullptr, a mutex will be allocated internally by the port, and destroyed with the port.

Implements yarp::os::Contactable.

Definition at line 679 of file Port.cpp.

◆ setEnvelope()

bool Port::setEnvelope ( PortWriter envelope)
overridevirtual

Set an envelope (e.g., a timestamp) to the next message which will be sent.

You must be sure to match the type of your envelope for setEnvelope with whatever will be read using getEnvelope. The Stamp class is a typical choice for timestamps. The Bottle class also works as an envelope, but it is not specialized to be efficient.

Currently, for proper operation, the envelope must serialize correctly in text-mode (even if you do not explicitly use text-mode connections). Bottle or Stamp are good choices.

Parameters
envelopeinformation to add to the next message which will be sent
Returns
true iff setting the envelope was successful

Implements yarp::os::Contactable.

Definition at line 542 of file Port.cpp.

◆ setInputMode()

void Port::setInputMode ( bool  expectInput)
overridevirtual

Configure the port to allow or forbid inputs.

By default, ports allow anything.

Parameters
expectInputset to true if this port will be used for input

Implements yarp::os::Contactable.

Definition at line 606 of file Port.cpp.

◆ setOutputMode()

void Port::setOutputMode ( bool  expectOutput)
overridevirtual

Configure the port to allow or forbid outputs.

By default, ports allow anything.

Parameters
expectOutputset to true if this port will be used for output

Implements yarp::os::Contactable.

Definition at line 614 of file Port.cpp.

◆ setReader()

void Port::setReader ( PortReader reader)
overridevirtual

Set an external reader for port data.

Parameters
readerthe external reader to use

Implements yarp::os::Contactable.

Examples:
port_power/ex0300_port_callback.cpp, and port_power/ex0402_port_callback_reply.cpp.

Definition at line 505 of file Port.cpp.

◆ setReaderCreator()

void Port::setReaderCreator ( PortReaderCreator creator)

Set a creator for readers for port data.

Every port that input is received from will be automatically given its own reader. Handy if you care about the identity of the receiver.

Parameters
creatorthe "factory" for creating PortReader object

Definition at line 519 of file Port.cpp.

◆ setReporter()

void Port::setReporter ( PortReport reporter)
overridevirtual

Set a callback to be called upon any future connections and disconnections to/from the port.

To get information on the current connections that exist, use the getReport method instead.

Parameters
reportercallback for port event/state information

Implements yarp::os::Contactable.

Definition at line 576 of file Port.cpp.

◆ setRpcMode()

void Port::setRpcMode ( bool  expectRpc)
overridevirtual

Configure the port to be RPC only.

By default all ports can be used for RPC or streaming communication.

Parameters
expectRpcset to true if this port will be used for RPC only

Implements yarp::os::Contactable.

Definition at line 622 of file Port.cpp.

◆ setTimeout()

bool Port::setTimeout ( float  timeout)

Set a timeout on network operations.

Use a negative number to wait forever (this is the default behavior). Call this method early, since it won't affect connections that have already been made.

Parameters
timeoutnumber of seconds to wait for individual network operations to complete (negative to wait forever).

Definition at line 630 of file Port.cpp.

◆ setVerbosity()

void Port::setVerbosity ( int  level)

Set whether the port should issue messages about its operations.

Parameters
levelverbosity level, -1 to inhibit messages.

Definition at line 636 of file Port.cpp.

◆ sharedOpen()

bool Port::sharedOpen ( Port port)

Open a port wrapping an existing port.

Definition at line 63 of file Port.cpp.

◆ tryLockCallback()

bool Port::tryLockCallback ( )
overridevirtual

Try to lock callbacks until unlockCallback() is called.

Has no effect if no lock has been set via a call to setCallbackLock(). Returns immediately.

Returns
true if callbacks were locked by this call, false if they were already locked.

Implements yarp::os::Contactable.

Definition at line 697 of file Port.cpp.

◆ unlockCallback()

void Port::unlockCallback ( )
overridevirtual

Unlock callbacks.

Implements yarp::os::Contactable.

Definition at line 702 of file Port.cpp.

◆ where()

Contact Port::where ( ) const
overridevirtual

Returns information about how this port can be reached.

Returns
network parameters for this port

Implements yarp::os::Contactable.

Definition at line 409 of file Port.cpp.

◆ write() [1/2]

bool Port::write ( const PortWriter writer,
const PortWriter callback = nullptr 
) const
overridevirtual

Write an object to the port.

Parameters
writerany object that knows how to write itself to a network connection - see for example Bottle
callbackobject on which to call onCompletion() after write is done (otherwise writer.onCompletion() is called)
Returns
true iff the object is successfully written

Implements yarp::os::UnbufferedContactable.

Examples:
os/portable_pair.cpp, os/simple_sender.cpp, port_power/ex0001_sender.cpp, port_power/ex0400_expect_reply.cpp, port_power/ex0501_raw_target_sender.cpp, port_power/ex0504_serial_target_sender.cpp, port_power/ex0506_compliant_target_sender.cpp, port_power/ex0508_alternative_compliant_target_sender.cpp, and portaudio/sound_sender_mic.cpp.

Definition at line 437 of file Port.cpp.

◆ write() [2/2]

bool Port::write ( const PortWriter writer,
PortReader reader,
const PortWriter callback = nullptr 
) const
overridevirtual

Write an object to the port, then expect one back.

Parameters
writerany object that knows how to write itself to a network connection - see for example Bottle
readerany object that knows how to read itself from a network connection - see for example Bottle
callbackobject on which to call onCompletion() after write is done (otherwise writer.onCompletion() is called)
Returns
true iff an object is successfully written and read

Implements yarp::os::UnbufferedContactable.

Definition at line 458 of file Port.cpp.

Member Data Documentation

◆ implementation

void* yarp::os::Port::implementation
private

Definition at line 259 of file Port.h.

◆ owned

bool yarp::os::Port::owned
private

Definition at line 260 of file Port.h.


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