thread::Writer< T > Class Template Reference

A Writer is used to write items to a Channel. More...

#include <cpp/symbian/concurrency/common/thread/channel.h>

Public Member Functions
	Writer (const Writer &)=delete
Writer &	operator= (const Writer &)=delete
void	Write (const T &item)
	Writes the given item to the channel, blocking until it can be written.
void	Write (T &&item)
	Writes the given item to the channel, blocking until it can be written.
void	Close ()
	Marks the channel as closed, notifying any waiting readers.
Case	OnWrite (const T &item)
	Returns a Case that can be used to write the given item to the channel.
Case	OnWrite (T &&item)
	Returns a Case that can be used to write the given item to the channel.
bool	WriteUnlessCancelled (const T &item)
	Returns false iff the calling fiber is cancelled before the value can be written.
bool	WriteUnlessCancelled (T &&item)
	Returns false iff the calling fiber is cancelled before the value can be written.
	Writer (const Writer &)=delete
Writer &	operator= (const Writer &)=delete
void	Write (T &&item)
void	Write (const T &item)
Case	OnWrite (T &&item)
Case	OnWrite (const T &item)
bool	WriteUnlessCancelled (T &&item)
bool	WriteUnlessCancelled (const T &item)
void	Close ()

Friends
class	Channel< T >

Detailed Description

template<class T>
class thread::Writer< T >

A Writer is used to write items to a Channel.

You can get a pointer to a Writer by calling Channel<T>::writer(), which is the object that you should pass to code that needs to write to the channel. Writers must be closed by calling Writer::Close() when the communication is done, to notify any waiting readers that no more items will be written to the channel.

Constructor & Destructor Documentation

Writer() [1/2]

template<class T >

thread::Writer< T >::Writer ( const Writer< T > &  )

delete

Writer() [2/2]

template<class T >

thread::Writer< T >::Writer ( const Writer< T > &  )

delete

Member Function Documentation

Close() [1/2]

template<typename T >

void thread::Writer< T >::Close

(

)

Marks the channel as closed, notifying any waiting readers.

See Reader::Read(). May be called at most once.

Close() [2/2]

template<class T >

void thread::Writer< T >::Close ( )

inline

OnWrite() [1/4]

template<typename T >

Case thread::Writer< T >::OnWrite

(

const T &

item

)

Returns a Case that can be used to write the given item to the channel.

Note

The lifetime of the item must be guaranteed to span the call to Select() with this case. Care must be taken when passing temporaries whose lifetime may only be guaranteed for the current statement. For example:

// Legal: int(23)'s lifetime extends to end of statement.
int index = thread::Select({ c_0, c_1, writer->OnWrite(23) });
 
// Illegal: Lifetime of int(19) not guaranteed beyond c's
// declaration.
thread::Case c = writer->OnWrite(19);
int index = thread::Select({ c, ... });

Parameters

item	The item to write to the channel. If the case is selected, ownership of the item is moved to the channel.

OnWrite() [2/4]

template<class T >

Case thread::Writer< T >::OnWrite ( const T &  item )

inline

OnWrite() [3/4]

template<typename T >

Case thread::Writer< T >::OnWrite

(

T &&

item

)

Returns a Case that can be used to write the given item to the channel.

The item is not mutated (moved from) unless the returned Case is selected.

Note

The item is not mutated (moved from) unless the returned Case is selected. For example:

// This is safe, ownership is only moved from if the case is selected.
auto unique_ptr = absl::make_unique<T>();
int index = thread::Select({ c_0, c_1,
                             writer->OnWrite(std::move(unique_ptr)) });
if (index != 2) {
  unique_ptr->Foo();
}

Parameters

item	The item to write to the channel. If the case is selected, ownership of the item is moved to the channel.

OnWrite() [4/4]

template<class T >

Case thread::Writer< T >::OnWrite ( T &&  item )

inline

operator=() [1/2]

template<class T >

Writer & thread::Writer< T >::operator= ( const Writer< T > &  )

delete

operator=() [2/2]

template<class T >

Writer & thread::Writer< T >::operator= ( const Writer< T > &  )

delete

Write() [1/4]

template<typename T >

void thread::Writer< T >::Write

(

const T &

item

)

Writes the given item to the channel, blocking until it can be written.

If the channel is closed, this will throw an exception.

Note

The item is copied into the channel, so it must be copy-constructible.

Write() [2/4]

template<class T >

void thread::Writer< T >::Write ( const T &  item )

inline

Write() [3/4]

template<typename T >

void thread::Writer< T >::Write

(

T &&

item

)

Writes the given item to the channel, blocking until it can be written.

If the channel is closed, this will throw an exception.

Note

The item is moved into the channel, so it must be move-constructible.

Write() [4/4]

template<class T >

void thread::Writer< T >::Write ( T &&  item )

inline

WriteUnlessCancelled() [1/4]

template<typename T >

bool thread::Writer< T >::WriteUnlessCancelled

(

const T &

item

)

Returns false iff the calling fiber is cancelled before the value can be written.

Parameters

item	The item to write to the channel.

Returns

True if the item was written to the channel, false if the calling fiber was cancelled before the item could be written.

WriteUnlessCancelled() [2/4]

template<class T >

bool thread::Writer< T >::WriteUnlessCancelled ( const T &  item )

inline

WriteUnlessCancelled() [3/4]

template<typename T >

bool thread::Writer< T >::WriteUnlessCancelled

(

T &&

item

)

Returns false iff the calling fiber is cancelled before the value can be written.

Note

The item is only moved into the channel if the function returns true.

Parameters

item	The item to write to the channel. If the function returns true, the ownership of the item is moved to the channel.

Returns

True if the item was written to the channel, false if the calling fiber was cancelled before the item could be written.

WriteUnlessCancelled() [4/4]

template<class T >

bool thread::Writer< T >::WriteUnlessCancelled ( T &&  item )

inline

Friends And Related Symbol Documentation

Channel< T >

template<class T >

friend class Channel< T >

friend

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

• cpp/symbian/concurrency/common/thread/channel.h
• cpp/symbian/concurrency/guest/thread/channel.h