Xapian provides an interator-based interface to all search results.
So it was natural to make notmuch_messages_t be iterator-based as
well. Which we did originally.
But we ran into a problem when we added two APIs, (_get_replies and
_get_toplevel_messages), that want to return a messages iterator
that's *not* based on a Xapian search result. My original compromise
was to use notmuch_message_list_t as the basis for all returned
messages iterators in the public interface.
This had the problem of introducing extra latency at the beginning
of a search for messages, (the call would block while iterating over
all results from Xapian, converting to a message list).
In this commit, we remove that initial conversion and instead provide
two alternate implementations of notmuch_messages_t (one on top of a
Xapian iterator and one on top of a message list).
With this change, I tested a "notmuch search" returning *many* results
as previously taking about 7 seconds before results started appearing,
and now taking only 2 seconds.
Previously, notmuch_query_search_threads would do all the work, so the
caller would block until all results were processed. Now, we do the
work as we go, as the caller iterates with notmuch_threads_next. This
means that once results start coming back from "notmuch search" they
just keep continually streaming.
There's still some initial blocking before the first results appear
because the notmuch_messages_t object has the same bug (for now).
This was a poor workaround around the fact that the existing
notmuch_threads_t object is implemented poorly. It's got a fine
iterartor-based interface, but the implementation does all of the
work up-front in _create rather than doing the work incrementally
while iterating.
So to start fixing this, first get rid of all the hacks we had working
around this. This drops the --first and --max-threads options from the
search command, (but hopefully nobody was using them
anyway---notmuch.el certainly wasn't).
Getting the count of matching threads or messages is a fairly
expensive operation. Xapian provides a very efficient mechanism that
returns an approximate value, so use that for this new command.
This returns the number of matching messages, not threads, as that is
cheap to compute.
Signed-off-by: Keith Packard <keithp@keithp.com>
If an earlier exception occurred, then it's not unexpected for the
flush to fail as well. So in that case, we'll silently catch the
exception. Otherwise, make some noise about things going wrong at the
time of flush.
In my script containing a series of queries to be run on new mail for
setting up tags, it's nice to see which query I typed wrong.
Signed-off-by: Eric Anholt <eric@anholt.net>
As suggested by Keith in FLAG_PURE_NOT allows for expressions like:
notmuch search NOT tag:inbox
Note that this way a search like:
notmuch search foobar NOT tag:inbox
should not be written instead:
notmuch search foobar AND NOT tag:inbox
In my opinion, the latter feels more natural and is somewhat more explicit.
It gives a better clue of what the search is about instead of assuming that
an implicit AND operator is there.
This is what most people want for a _search_ command. It's often
different for actually reading mail in an inbox, (where it makes more
sense to have results displayed in chronological order), but in such a
case, ther user is likely using an interface that can simply pass the
--sort=oldest-first option to "notmuch search".
Here we're also change the sort enum from NOTMUCH_SORT_DATE and
NOTMUCH_SORT_DATE_REVERSE to NOTMUCH_SORT_OLDEST_FIRST and
NOTMUCH_SORT_NEWEST_FIRST. Similarly we replace the --reverse option
to "notmuch search" with two options: --sort=oldest-first and
--sort=newest-first.
Finally, these changes are all tracked in the emacs interface, (which
has no change in its behavior).
Previously, the notmuch_messages_t object was a linked list built on
top of a linked-list node with the odd name of notmuch_message_list_t.
Now, we've got much more sane naming with notmuch_message_list_t being
a list built on a linked-list node named notmuch_message_node_t. And
now the public notmuch_messages_t object is a separate iterator based
on notmuch_message_node_t. This means the interfaces for the new
notmuch_message_list_t object are now made available to the library
internals.
The new object is simply a linked-list of notmuch_message_t objects,
(unlike the old object which contained a couple of Xapian iterators).
This works now by the query code immediately iterator over all results
and creating notmuch_message_t objects for them, (rather than waiting
to create the objects until the notmuch_messages_get call as we did
earlier).
The point of this change is to allow other instances of lists of
messages, (such as in notmuch_thread_t), that are not directly related
to Xapian search results.
Note that the difference between thread results in date order and
thread results in reverse-date order is not simply a matter of
reversing the final results. When sorting in date order, the threads
are sorted by the oldest message in the thread. When sorting in
reverse-date order, the threads are sorted by the newest message in
the thread.
This difference means that we might want an explicit option in the
interface to reverse the order, (even though the default will be to
display the inbox in date order and global searches in reverse-date
order).
Note that we don't print the number of *unread* messages, but instead
the number of messages that matched the search terms. This is in
keeping with our philosophy that the inbox is nothing more than a
search view. If we search for messages with an inbox tag, then that's
what we'll get a count of. (And if somebody does want to see unread
counts, then they can search for the "unread" tag.)
Getting the number of matched messages is really nice when doing
historical searches. For example in a search like:
notmuch search tag:sent
(where the "sent" tag has been applied to all messages originating
from the user's email address)---here it's really nice to be able to
see a thread where the user just mentioned one point [1/13] vs. really
getting involved in the discussion [10/29].
We've now expanded the notmuch_thread_create function to fire off a
secondary database query to find all the messages that belong to this
particular thread. This allows us to now have the complete authors'
list for the thread, and will also make it trivial to print accurate
message counts for threads in the future.
I thought it would be safe enough to return a few extra threads,
(since we happened to already get the relevant messages out of the
database). The problem is that then requires the caller to carefully
read the number of threads returned and adjust its next "first" value
accordingly. The interface is much simpler to use if we simply return
exactly what is asked for and no more.
This serves me right for committing untested code. The
notmuch_query_search_threads was totally broken, (it didn't properly
treat -1 as being unlimited and instead returned no threads in that
case).
The library interface now allows the caller to do incremental searches,
(such as one page of results at a time). Next we'll just need to hook
this up to "notmuch search" and the emacs interface.
