wpi::uv::Loop Class Reference

Event loop. More...

#include <wpinet/uv/Loop.h>

Inheritance diagram for wpi::uv::Loop:

Public Types
enum	Mode { kDefault = UV_RUN_DEFAULT , kOnce = UV_RUN_ONCE , kNoWait = UV_RUN_NOWAIT }
using	Time = std::chrono::duration< uint64_t, std::milli >

Public Member Functions
	Loop (const private_init &) noexcept
	Loop (const Loop &)=delete
Loop &	operator= (const Loop &)=delete
	Loop (Loop &&oth)=delete
Loop &	operator= (Loop &&oth)=delete
	~Loop () noexcept
void	SetClosing ()
	Set the loop closing flag. More...
bool	IsClosing () const
	Return the loop closed flag. More...
void	Close ()
	Release all internal loop resources. More...
bool	Run (Mode mode=kDefault)
	Run the event loop. More...
bool	IsAlive () const noexcept
	Check if there are active resources. More...
void	Stop () noexcept
	Stop the event loop. More...
int	GetDescriptor () const noexcept
	Get backend file descriptor. More...
std::pair< bool, Time >	GetTimeout () const noexcept
	Get the poll timeout. More...
Time	Now () const noexcept
	Return the current timestamp in milliseconds. More...
void	UpdateTime () noexcept
	Update the event loop’s concept of now. More...
void	Walk (function_ref< void(Handle &)> callback)
	Walk the list of handles. More...
void	Fork ()
	Reinitialize any kernel state necessary in the child process after a fork(2) system call. More...
uv_loop_t *	GetRaw () const noexcept
	Get the underlying event loop data structure. More...
template<typename T = void>
std::shared_ptr< T >	GetData () const
	Gets user-defined data. More...
void	SetData (std::shared_ptr< void > data)
	Sets user-defined data. More...
std::thread::id	GetThreadId () const
	Get the thread id of the loop thread. More...
void	ReportError (int err)
	Reports error. More...

Static Public Member Functions
static std::shared_ptr< Loop >	Create ()
	Create a new event loop. More...
static std::shared_ptr< Loop >	GetDefault ()
	Create the default event loop. More...

Public Attributes
sig::Signal< Error >	error
	Error signal. More...

Detailed Description

Event loop.

The event loop is the central part of uv functionality. It takes care of polling for I/O and scheduling signals to be generated based on different sources of events.

The event loop is not moveable, copyable, or directly constructible. Use Create() to create an event loop, or GetDefault() to get the default loop if you know your program will only have a single one.

Member Typedef Documentation

Time

using wpi::uv::Loop::Time = std::chrono::duration<uint64_t, std::milli>

Member Enumeration Documentation

Mode

enum wpi::uv::Loop::Mode

Enumerator
kDefault
kOnce
kNoWait

Constructor & Destructor Documentation

Loop() [1/3]

wpi::uv::Loop::Loop ( const private_init &  )

explicitnoexcept

Loop() [2/3]

wpi::uv::Loop::Loop ( const Loop &  )

delete

Loop() [3/3]

wpi::uv::Loop::Loop ( Loop &&  oth )

delete

~Loop()

wpi::uv::Loop::~Loop ( )

noexcept

Member Function Documentation

Close()

void wpi::uv::Loop::Close

(

)

Release all internal loop resources.

Call this function only when the loop has finished executing and all open handles and requests have been closed, or the loop will emit an error.

error() will be emitted in case of errors.

Create()

static std::shared_ptr< Loop > wpi::uv::Loop::Create ( )

static

Create a new event loop.

The created loop is not the default event loop.

Returns

The newly created loop. May return nullptr if a failure occurs.

Fork()

void wpi::uv::Loop::Fork

(

)

Reinitialize any kernel state necessary in the child process after a fork(2) system call.

Previously started watchers will continue to be started in the child process.

It is necessary to explicitly call this function on every event loop created in the parent process that you plan to continue to use in the child, including the default loop (even if you don’t continue to use it in the parent). This function must be called before calling any API function using the loop in the child. Failure to do so will result in undefined behaviour, possibly including duplicate events delivered to both parent and child or aborting the child process.

When possible, it is preferred to create a new loop in the child process instead of reusing a loop created in the parent. New loops created in the child process after the fork should not use this function.

Note that this function is not implemented on Windows. Note also that this function is experimental in libuv. It may contain bugs, and is subject to change or removal. API and ABI stability is not guaranteed.

error() will be emitted in case of errors.

GetData()

template<typename T = void>

std::shared_ptr< T > wpi::uv::Loop::GetData ( ) const

inline

Gets user-defined data.

Returns

User-defined data if any, nullptr otherwise.

GetDefault()

static std::shared_ptr< Loop > wpi::uv::Loop::GetDefault ( )

static

Create the default event loop.

Only use this event loop if a single loop is needed for the entire application.

Returns

The newly created loop. May return nullptr if a failure occurs.

GetDescriptor()

int wpi::uv::Loop::GetDescriptor ( ) const

inlinenoexcept

Get backend file descriptor.

Only kqueue, epoll and event ports are supported. This can be used in conjunction with run(Loop::kNoWait) to poll in one thread and run the event loop’s callbacks in another.

Returns

The backend file descriptor.

GetRaw()

uv_loop_t * wpi::uv::Loop::GetRaw ( ) const

inlinenoexcept

Get the underlying event loop data structure.

Returns

The underlying event loop data structure.

GetThreadId()

std::thread::id wpi::uv::Loop::GetThreadId ( ) const

inline

Get the thread id of the loop thread.

If the loop is not currently running, returns default-constructed thread id.

GetTimeout()

std::pair< bool, Time > wpi::uv::Loop::GetTimeout ( ) const

inlinenoexcept

Get the poll timeout.

Returns

A std::pair composed of a boolean value that is true in case of valid timeout, false otherwise, and the timeout (std::chrono::duration<uint64_t, std::milli>).

IsAlive()

bool wpi::uv::Loop::IsAlive ( ) const

inlinenoexcept

Check if there are active resources.

Returns

True if there are active resources in the loop.

IsClosing()

bool wpi::uv::Loop::IsClosing ( ) const

inline

Return the loop closed flag.

Returns

True if SetClosed() has been called.

Now()

Time wpi::uv::Loop::Now ( ) const

inlinenoexcept

Return the current timestamp in milliseconds.

The timestamp is cached at the start of the event loop tick. The timestamp increases monotonically from some arbitrary point in time. Don’t make assumptions about the starting point, you will only get disappointed.

Returns

The current timestamp in milliseconds (actual type is std::chrono::duration<uint64_t, std::milli>).

operator=() [1/2]

Loop & wpi::uv::Loop::operator= ( const Loop &  )

delete

operator=() [2/2]

Loop & wpi::uv::Loop::operator= ( Loop &&  oth )

delete

ReportError()

void wpi::uv::Loop::ReportError ( int  err )

inline

Reports error.

Parameters

err	Error code

Run()

bool wpi::uv::Loop::Run ( Mode  mode = kDefault )

inline

Run the event loop.

Available modes are:

• Loop::kDefault: Run the event loop until there are no active and referenced handles or requests.
• Loop::kOnce: Run a single event loop iteration. Note that this function blocksif there are no pending callbacks.
• Loop::kNoWait: Run a single event loop iteration, but don't block if there are no pending callbacks.

Returns

True when done, false in all other cases.

SetClosing()

void wpi::uv::Loop::SetClosing ( )

inline

Set the loop closing flag.

This will prevent new handles from being created on the loop.

SetData()

void wpi::uv::Loop::SetData ( std::shared_ptr< void >  data )

inline

Sets user-defined data.

Parameters

data	User-defined arbitrary data.

Stop()

void wpi::uv::Loop::Stop ( )

inlinenoexcept

Stop the event loop.

This will cause Run() to end as soon as possible. This will happen not sooner than the next loop iteration. If this function was called before blocking for I/O, the loop won’t block for I/O on this iteration.

UpdateTime()

void wpi::uv::Loop::UpdateTime ( )

inlinenoexcept

Update the event loop’s concept of now.

The current time is cached at the start of the event loop tick in order to reduce the number of time-related system calls. You won’t normally need to call this function unless you have callbacks that block the event loop for longer periods of time, where longer is somewhat subjective but probably on the order of a millisecond or more.

Walk()

void wpi::uv::Loop::Walk

(

function_ref< void(Handle &)>

callback

)

Walk the list of handles.

The callback will be executed once for each handle that is still active.

Parameters

callback

A function to be invoked once for each active handle.

Member Data Documentation

error

sig::Signal<Error> wpi::uv::Loop::error

Error signal.

---

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

• wpinet/uv/Loop.h