What is the most useful way to present interface lists?

I’ve just rolled out a small update to the interface cross reference, nothing major, just fixing a few bugs and I’ve put up what looks like the final set of interfaces for 1.9.1b2.

I’ve now figured out the best way to gather the interface lists and so the cross reference now includes all interfaces used in all 3 major platforms of Firefox. It is relatively simple for me to add the interfaces for other applications now but this got me thinking about what kind of uses people are making of this and how the multi-OS, multi-app interfaces should be presented. A few ideas came to mind:

  • App developers probably just want to see the interfaces in their app, either only those that appear for all operating systems or those for a specific OS in some cases.
  • Add-on developers probably want to see some kind of shared set of interfaces (what you might call gecko/toolkit) that appear for all apps they are targeting, unfortunately this changes depending on the set of apps. Again they probably want for all OS or for a specific OS.
  • Maybe I shouldn’t even bother doing anything and just include a note in the interface display about where the interface actually exists.

I’m sure other people have other ideas of how it might work, any suggestions?

Improving the API references

I forgot to add to my last post some information about what I currently had in mind to improve about the API reference I’ve been working on. Any further suggestions people have are very welcome, but here is the current few ideas I have.

Currently it only indexes Firefox and Gecko interfaces, in fact it only indexes those used by an OSX build of Firefox. It would be nice to be able to index interfaces for all the main applications and for all the platforms. There are a couple of issues with this. Firstly I’d want the UI to work so people viewing it could select what set of interfaces they wanted to see. Secondly actually building the lists of interfaces for each application and OS is going to be pretty tricky I think. So far I’ve resorted to building Firefox then looking in dist/idl. This works but it is time consuming. Possibly I might be able to come up with some clever nonsense to make the build system only compile idls but we’ll see.

It would be nice to be able to include a list of the component contract ids available in the platform and what interfaces they implement. This is I think pretty difficult to do just by parsing the source files. Potentially a little extension could run in the app and do some looking through Components.classes to find this out. One issue here though is there is no way to tell whether components are services or not so instantiating them is potentially problematic. This is a problem that could be solved by brute force, or maybe doing a special instrumented build.

So those are my main two ideas, if anyone has any suggestions on how to make those tasks easier or for other things that should be there then shout them out.

API reference updates

Since my first announcement about my little api reference tool I’ve slowly been working on updates to make it more useful and easier to navigate around. I’ve now gone and pushed the latest version live. A few of the new features:

  • The main and platform lists of interfaces are split by the module where the interface lives.
  • Interface lists have a quick filter box, type in it to filter the list quickly.
  • Any interfaces used as return types or parameters are now links to get you straight to the information about them.
  • Full IDL support so it now lists all the special attributes and for the uninitiated they have tooltips that explain what they mean.
  • You can now list all usage of an interface by other interfaces.
  • Constants are ordered the same as in the source IDL since they tend to make more sense that way.
  • Includes direct links to the source IDL file.

I’ve also updated the database with the latest APIs in 1.9.1b2pre and as soon as 1.9.1b2 is frozen I’ll update it again just to be sure it has the latest versions.

You can also search the API for interfaces. There isn’t any UI for this right now but it is perfectly set up for a smart bookmark. Just use http://www.oxymoronical.com/experiments/apidocs/search/interface/%s for the url and an appropriate keyword and you can do quick searches for substrings of the interface name.

Finding API Changes

I started a small discussion on the newsgroups the other day wondering about the numbers of API changes that had landed on trunk since 1.9.0. It was a short discussion, maybe partly because all I had to go on were the vague metrics that mercurial could give me. It also evolved a little into a discussion of how add-on developers we’re meant to find out about API changes. It’s true that as developers we are getting better at trying to announce our changes as much as possible, but inevitably we miss some, and if you don’t track the announcements what then?

Yesterday on IRC ted jokingly made the comment that I could use the idl parser than bsmedberg wrote in python a short time ago to find out more about the API changes. I’ve been hard pressed on other work lately so it wasn’t long before the prospect of knocking together a little side project had me too interested to do anything else. In a short space of time I had something that could parse all the in-tree idl files into a sqlite database that I could then query. It wasn’t long after that that I got a small web app written to display the content of the database, but I spent some more time today getting it a bit more useful before I showed it to the rest of the world.

So here it is, the API viewer. You can look at any interface in any of the platform versions that I’ve bothered to scan. And here is the more interesting bit, you can compare two platforms to see what interfaces changed. Not happy there? Well you can also compare an interface in different platform versions in a sort of diff like display.

I should note that it is only indexing the core and Firefox interfaces for now, and it’s close to indexing all of the idl files from the sources, many of which don’t make it into the final build (which makes life interesting as it turns out some of them are invalid xpidl!). So you can’t trust that interfaces you find are necessarily useful etc.

The web app is really a prototype right now. Navigation is probably a bit clunky and it’ll need more work to be really useful but I wondered what other people thought of it. So what do you think? Is it useful? What other interesting information might we be able to grab automatically like this?

Update: I’ve added details of the current trunk, 1.9.1b2pre as of today so you can see what changes are coming since the last beta. Not sure how often I’ll keep that up to date though.

Why 2 SDKs are better than 1

In the past the Gecko SDK was somewhat limited. You could compile against it, but only if you were using frozen components, of which there are exceptionally few. You can build an application with only them, but I’d be startled if any moderately complicated app or extension gets by with only them. Thankfully this has changed for 1.9 and the new style SDK contains all interfaces and headers, frozen and unfrozen. This gives you access to lots more, though has the minor disadvantage that you have to keep an eye on what you are using as it could break in the future.

Just one snag with this new SDK though. The Mac version was missing something. Like a bunch of the tools and the XUL framework snapshot. It turns out that the method of packaging the SDK really didn’t work too well when you’re building a universal XULRunner, which is of course what we do.

After a bunch of work by plasticmillion and myself and a bunch of reviewing and generally dealing with our pesky questions by bsmedberg, the Mac XULRunner tinderbox is now producing working SDKs for every build. And I do mean the plural there. Building just one unified SDK is pretty tricky, even manually, let alone trying to make the Mozilla build system do it. Instead two SDKs are build, one for the powerpc architecture and one for intel. This actually works out well if you are producing an unified application using the Mozilla build system. All you really need are these magic lines in the mozconfig for your application:

ac_add_app_options ppc  --with-libxul-sdk=<path to powerpc sdk>
ac_add_app_options i386 --with-libxul-sdk=<path to intel sdk>

I’m just about to update the McCoy application to use the SDKs rather than having to build a full XULRunner alongside. This will make building McCoy simpler, particularly a unified Mac version which for the initial release I pretty much had to stitch together by hand. It will also I hope resolve some stability issues on Linux. I hope to have a new version out soon with some popularly requested new features.

I should note that the powerpc SDK is not a pure powerpc SDK. It is designed to be used to compile the powerpc portion of an applicaton using a build machine that is intel based. Unfortunately some of the important build tools cannot be cross-compiled for the powerpc architecture since the dependencies are only one architecture. Hopefully this will suit the majority of people.

Mac Intel Gecko SDK

Update: Mozilla now produce intel gecko SDKs so there is no need to use the version I have put here, I’ll leave it for posterity though.

It’s currently a bit of a pain building xpcom components in intel macs. The only officially available sdk is ppc only. Until Mozilla come up with an official version, here is an intel build of it for those that want it: gecko-sdk-mac-intel-

As the name suggests it’s built against Gecko To the best of my knowledge it’s right but please don’t bug me if you can’t get your component to work with it unless you’re pretty positive that it’s the sdk that’s wrong.

Right now I have no clue how you’d go about making a universal sdk, maybe if you know of a simple way then you could get in touch.