348545 - Consolidating JSString builders

Status: RESOLVED DUPLICATE of bug 700169

(Core :: JavaScript Engine, enhancement)

Description

[Igor Bukanov]

Currently a few places in SpiderMonkey contains code to assemble a jschar buffer to build JSString* instance later. See for example, various toSource implementations. It would be nice to consolidate such code behind a simple API.

Comment 1

[Igor Bukanov]

Attachment: Proof-on-cocept

This is a proof of concept that adds new JSStringBaker API to jsstr.c and changes errorInstance.stack builder to use it. The API allows to perform error checking only one per a sequnce of string appends decreasing "if (failed)" noise in the code.

The most ugly part of the patch is SBIncreaseCapacity function is jsstr.c. Since the API has options to specify a capacity hint and a hard limit on the string length, SBIncreaseCapacity has to deal with quite a few cases leading to messy code. Perhaps it can simplified.

If the main idea behind API is OK and naming is tolerable, I will extend the patch to switch toSource implementations.

Comment 2

[Brendan Eich [:brendan]]

StringBaker, heh. Some might prefer more prosaic StringBuilder, but I like it.

This bug should be prioritized against more pressing mozilla1.9 perf work of course, but I didn't mean to forget to reply in favor.

/be

Comment 3

[Igor Bukanov]

I am not working on the bug right now.

Comment 4

[Tom S [:evilpie]]

Ups noticed that bug too late.