897594 - Reduce number of sourcemap lookups when setting breakpoints

Status: RESOLVED FIXED

(DevTools :: Debugger, defect, P5)

Description

[Jim Blandy :jimb]

I'm having difficulty reading it, but the code starting here:

http://hg.mozilla.org/mozilla-central/file/b3fcd828cadc/toolkit/devtools/server/actors/script.js#l680

seems to do way more work than necessary to give the correct answer. If the response from _createAndStoreBreakpoint has an actualLocation property, then that is a generated location, so we need to get its original location, and return that in the packet --- if it differs from what was given in the request.

But if there is no actualLocation property there, then there's no need to do any location mapping at all: the breakpoint was set where requested, and the location that appears in the request is correct.

Comment 1

[Jim Blandy :jimb]

"Way more" is an exaggeration. I think we can avoid an unconditional call to getOriginalLocation.

I guess it comes down to: I can't see why originalLocation, as computed here:
http://hg.mozilla.org/mozilla-central/file/b3fcd828cadc/toolkit/devtools/server/actors/script.js#l684

... is going to be meaningfully different from originalSource, originalLine, originalColumn as found in aRequest.location.

Comment 2

[Tom Tromey :tromey]

This will be obsolete once the old debugger is removed.