JobQueue Class Reference

Implement the ECMAScript Job Queue: https://www.ecma-international.org/ecma-262/9.0/index.html#sec-jobs-and-job-queues. More...

#include <JobQueue.hh>

Inheritance diagram for JobQueue:

Collaboration diagram for JobQueue:

Public Member Functions
	JobQueue (JSContext *cx)
	~JobQueue ()=default
bool	init (JSContext *cx)
	Initialize PythonMonkey's event-loop job queue.
JSObject *	getIncumbentGlobal (JSContext *cx) override
	Ask the embedding for the incumbent global.
bool	enqueuePromiseJob (JSContext *cx, JS::HandleObject promise, JS::HandleObject job, JS::HandleObject allocationSite, JS::HandleObject incumbentGlobal) override
	Enqueue a reaction job job for promise, which was allocated at allocationSite. Provide incumbentGlobal as the incumbent global for the reaction job's execution.
void	runJobs (JSContext *cx) override
	Run all jobs in the queue. Running one job may enqueue others; continue to run jobs until the queue is empty.
bool	empty () const override
bool	isDrainingStopped () const override
void	queueFinalizationRegistryCallback (JSFunction *callback)
	Appends a callback to the queue of FinalizationRegistry callbacks.
bool	runFinalizationRegistryCallbacks (JSContext *cx)
	Runs the accumulated queue of FinalizationRegistry callbacks.

Detailed Description

Implement the ECMAScript Job Queue: https://www.ecma-international.org/ecma-262/9.0/index.html#sec-jobs-and-job-queues.

See also

https://hg.mozilla.org/releases/mozilla-esr102/file/5741ffa/js/public/Promise.h#l22

Constructor & Destructor Documentation

JobQueue()

JobQueue::JobQueue ( JSContext *  cx )

explicit

~JobQueue()

JobQueue::~JobQueue ( )

default

Member Function Documentation

empty()

bool JobQueue::empty ( ) const

override

Returns

true if the job queue is empty, false otherwise.

enqueuePromiseJob()

bool JobQueue::enqueuePromiseJob ( JSContext *  cx, JS::HandleObject  promise, JS::HandleObject  job, JS::HandleObject  allocationSite, JS::HandleObject  incumbentGlobal  )

override

Enqueue a reaction job job for promise, which was allocated at allocationSite. Provide incumbentGlobal as the incumbent global for the reaction job's execution.

promise can be null if the promise is optimized out. promise is guaranteed not to be optimized out if the promise has non-default user-interaction flag.

getIncumbentGlobal()

JSObject * JobQueue::getIncumbentGlobal ( JSContext *  cx )

override

Ask the embedding for the incumbent global.

SpiderMonkey doesn't itself have a notion of incumbent globals as defined by the HTML spec, so we need the embedding to provide this. See dom/script/ScriptSettings.h for details.

init()

bool JobQueue::init

(

JSContext *

cx

)

Initialize PythonMonkey's event-loop job queue.

Parameters

cx	- javascript context pointer

Returns

success

isDrainingStopped()

bool JobQueue::isDrainingStopped ( ) const

override

Returns

true if the job queue stopped draining, which results in empty() being false after runJobs().

queueFinalizationRegistryCallback()

void JobQueue::queueFinalizationRegistryCallback

(

JSFunction *

callback

)

Appends a callback to the queue of FinalizationRegistry callbacks.

Parameters

callback

- the callback to be queue'd

runFinalizationRegistryCallbacks()

bool JobQueue::runFinalizationRegistryCallbacks

(

JSContext *

cx

)

Runs the accumulated queue of FinalizationRegistry callbacks.

Parameters

cx	- Pointer to the JSContext

Returns

true - at least 1 callback was called

false - no callbacks were called

runJobs()

void JobQueue::runJobs ( JSContext *  cx )

override

Run all jobs in the queue. Running one job may enqueue others; continue to run jobs until the queue is empty.

Calling this method at the wrong time can break the web. The HTML spec indicates exactly when the job queue should be drained (in HTML jargon, when it should "perform a microtask checkpoint"), and doing so at other times can incompatibly change the semantics of programs that use promises or other microtask-based features.

This method is called only via AutoDebuggerJobQueueInterruption, used by the Debugger API implementation to ensure that the debuggee's job queue is protected from the debugger's own activity. See the comments on AutoDebuggerJobQueueInterruption.

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

• include/JobQueue.hh
• src/JobQueue.cc