Fix race conditions

[ausi]

Fixes #54

I found another race condition and fixed it in d6fd14b but I’m not sure if this works on all platforms.

[ausi]

but I’m not sure if this works on all platforms.

It doesn’t work on windows: Failed to remove file "…": unlink(…): Resource temporarily unavailable..

I don’t know how to fix that.

[aschempp]

Maybe using this hint?
https://github.com/composer/composer/blob/master/src/Composer/Util/Filesystem.php#L194-L200

[ausi]

No, that wouldn’t help. I would have to release the lock first before deleting the file and that would enable the race condition again.

[ausi]

A possible workaround might be to remove all file contents, release the lock and then unlink the file. When reading the file and it’s empty we could handle it the same way as if it didn’t exist at all.

[ausi]

As a workaround for windows we now retry to delete the file after releasing the lock if the first delete attemt fails (84f52c9)

[Toflar]

LGTM