Limiting the amount of headers to download ?

[Sergio Villar Senin <svillar igalia com>]

Hi,

it's easy to see how the average number of emails in user's inboxes has
dramatically increased especially after GMail's rise. Nowadays is quite
common to see users with 2000-3000 headers in their inboxes, and in a
near future 5000-6000 will be the average.

Although memory consumption in tinymail is absolutely fantastic even
with those huge numbers we have to take into account that there are some
operations like sorting or searching, that are really very time
consuming in small devices due to the enormous processing power they
need. Even the "innocent" get_headers operation (in combination with the
use of a tree model) is a really heavy operation when performed for the
first time in huge inboxes.

So taking into account that tinymail's main target are those
small/handheld devices I suggest to add a compiler option that when
enabled, will limit the amount of retrieved headers to some extent
(don't know yet, might be 1000 headers, or headers from last 2 months,
whatever... suggestions are welcomed)

What do you think?