Add support for grabbing Packages files using external programs.

Add support for grabbing Packages files using external programs.

If the user specifies FETCHCOMMAND_*, Portage should honor this when grabbing
Packages files. This allows users to setup support for grabbing Packages files
from other protocols.

BUG=chrome-os-partner:2026
TEST=Try downloading prebuilts from gs:// when FETCHCOMMAND_GS is setup in make.conf

Change-Id: I96b239819351633dd02d608954e81a1c363a4687

Committed: http://chrome-svn/viewvc/chromeos?view=rev&revision=719f524

[davidjames, 2011-02-09 00:30:24]

Portage already supports downloading the actual tarballs via an external
program, but it restricts the Packages file download to only be protocols
supported internally by Python (e.g. http, a few others). This CL allows us to
download Packages files over gs:// protocol if FETCHCOMMAND_GS is setup.

[anush, 2011-02-10 01:52:44]

LGTM. Zac may have better suggestions on how to preserve the file_get() api. 

On 2011/02/09 00:30:24, davidjames wrote:
> Portage already supports downloading the actual tarballs via an external
> program, but it restricts the Packages file download to only be protocols
> supported internally by Python (e.g. http, a few others). This CL allows us to
> download Packages files over gs:// protocol if FETCHCOMMAND_GS is setup.

[zmedico, 2011-02-14 04:05:38]

The patch looks good, so I've merged it upstream:

http://git.overlays.gentoo.org/gitweb/?p=proj/portage.git;a=commit;h=53f096c5...

Also, I've changed the FileNotFound to EnvironmentError so that it's caught:

http://git.overlays.gentoo.org/gitweb/?p=proj/portage.git;a=commit;h=334af57e...