On Wed, Jan 3, 2018 at 5:30 PM, Ben Kelly <bke...@mozilla.com> wrote: > On Wed, Jan 3, 2018 at 5:09 PM, Gabriele Svelto <gsve...@mozilla.com> wrote: >> So after validating my approach in that bug (which is almost ready) I've >> thought that it might be time to give the observer service the same >> treatment. First of all we'd have a list of topics (I've picked YAML for >> the list but it could be anything that fits the bill): > > Could we use our existing idl/webidl/ipdl for this? It would be nice not to > have to maintain another code generator in the tree if possible.
I don't understand this objection on two levels: 1) Why does maintaining another code generator in tree hurt anything? We have many one-off code generators for specific purposes: https://searchfox.org/mozilla-central/search?q=GENERATED_FILES&case=false®exp=false&path=moz.build Some of these use non-Python generators (e.g. the a11y files and gfx shaders), but there are probably enough to count on multiple hands. I would expect modifications of the code generator to be infrequent, and the code generator itself is liable to be a screenful or so of straightforward code. 2) How would one shoehorn this into *DL? The options that come to mind are: - Separate methods for every observer topic, which sounds terrible from a code duplication perspective. Though maybe this would be nice for JS clients, so we could say things like: Services.obs.notifyXPCOMShutdown(...) which would save on some xpconnect traffic and representing a large-ish enum in JS? - WebIDL enums (I think), which would carry a large space penalty and make everything that wants to use the observer service depend on code from dom/, which seems undesirable. - IDL enums, which aren't reflected into JS, so we'd need some custom work there. - IPDL doesn't even have the concept of definable enums, and wouldn't reflect things into JS, so we'd need even more work there. (Some of this may be desirable; we talked about extending IPDL bits into JS in Austin, and kmaglione felt this was reasonable, so...) The first and third don't sound *too* bad, but I don't think that writing a one-off code generator would be strictly worse... -Nathan _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
