Using port command to see installation method

[Nate Ijams]

And I suppose one follow up, if that is the case: how are upgrades 
handled by MacPorts when someone has originally installed a package from 
source vs binary?

Take this scenario:
– Install package X from source;
– Install package Y from binary;
– Later, both packages are upgraded in the ports tree; and
– I run `port upgrade outdated`.

Will X be upgraded from source, and Y from binary, so long as I do not 
run the command with `-s` or `b`? Or is the history ignored, and both 
will be upgraded by default from binary? Or is there a different 
behavior?