Bug 229148

Summary:

[webkitcorepy] Add CallByNeed object

Product:

WebKit

Reporter:

Jonathan Bedard <jbedard>

Component:

Tools / Tests

Assignee:

Jonathan Bedard <jbedard>

Status:

RESOLVED FIXED

Severity:

Normal

CC:

aakash_jain, dewei_zhu, slewis, webkit-bug-importer

Priority:

Keywords:

InRadar

Version:

WebKit Nightly Build

Hardware:

Unspecified

OS:

Unspecified

Attachments:

Description	Flags
Patch	none
Patch	none

Description Jonathan Bedard 2021-08-16 09:31:52 PDT

It's often the case that we want to defer the computation of an object until we actually need that object.  We should add a small wrapper object that allows us to do this in webkitcorepy.

Comment 1 Jonathan Bedard 2021-08-16 09:33:27 PDT

<rdar://problem/81817705>

Comment 2 Jonathan Bedard 2021-08-16 09:43:09 PDT

Created attachment 435612 [details]
Patch

Comment 3 dewei_zhu 2021-08-17 16:34:08 PDT

Comment on attachment 435612 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=435612&action=review

> Tools/Scripts/libraries/webkitcorepy/webkitcorepy/defer.py:24
> +class Defer(object):

It might cause confusion with "Deferred" in twisted module, which is more about async operation.
For this one, we want to defer the evaluation of 'callback', this is more like lazily evaluated. 
This also limits the callback to be a callable that takes no argument, would that work for what it's designed for?

> Tools/Scripts/libraries/webkitcorepy/webkitcorepy/tests/defer_unittest.py:34
> +

Maybe we also want to have a test case that the evaluation is actually deferred.

value = []
d = Defer(lambda: value.append('foo'))
self.assertEqual(len(value), 0)
d.value
self.assertEqual(len(value), 1)
self.assertEqual(value[0], 'foo').

Comment 4 Jonathan Bedard 2021-08-18 08:24:17 PDT

Created attachment 435768 [details]
Patch

Comment 5 Jonathan Bedard 2021-08-18 09:34:09 PDT

Committed r281191 (240635@main): <https://commits.webkit.org/240635@main>