env.getEnvironment return {} in standalone mode.

[rogemita]

NOTE: env.getEnvironment single-thread only

[rogemita]

We will going to prepare try2 with this revision points, thanks for your review =)!!!

[code-sur]

@dnarvaez, @rogemita
This code remains single-threaded, though the likelihood of failing is low, there is not guarantee of correctness in other contexts (i.e. future webkit versions or other browsers).
Also, I can't figure out an easy way to make it thread-safe.

Should we take some action due to this known issue?

[dnarvaez]

I tend to think adding a comment would be fine for now. I can't think of a way to avoid the race either, we might have to write a webkit extension and avoid the hack if it turns out we need to be multi thread safe.

[dnarvaez]

One possible approach to get rid of the race without having to write C code might be to fetch an activity://..../environment.json (dynamically generated on the python side). I sort of like that approach actually, it feels better of what we have now at least.

[dnarvaez]

(Breaking the contract with toolkit would be annoying for backward compatibility reason, but I'm not sure we should start worrying too much about that yet).

[rogemita]

I tend to think adding a comment would be fine for now.

so is ok at the moment, a message on getEnvironment function, like: ...

• FIXME: multi-threading unsupported
• single-threaded function

???

[dnarvaez]

Maybe "// FIXME we assume this code runs on the same thread as the javascript executed from python" or something like that.

[code-sur]

summary for try2:

• wrap callback inside a setTimeout
• create a ticket on bugs.sugarlabs.org: refactor env.isStandalone() testing the user-agent
• empty line after L13 in env.js
• remove unused var expectedEnv = {};
• add FIXME with the single-threaded assumtion

@dnarvaez, I'm going to fix those points and push directly (if you agree).
I'll rebase with master in order to merge fast-forward (without empty merge commit)

[dnarvaez]

Yup!

[code-sur]

pushed

Thanks for reviewing!