parse: Return IOError when including file with absolute path

* resolve_file was behaving different when relative and absolute
  paths were passed to it

* include relative-path/non-existent-file.inc
  works correctly resolve_file throws IOError, BBHandler.py:handle()
  doesn't catch it, ConfHandler.py:include() catches IOError and shows:
  DEBUG: CONF file 'relative-path/non-existent-file.inc' not found
* include /absolute-path/non-existent-file.inc
  was failing, because resolve_file just returns fn,
  BBHandler.py:handle() calls bb.parse.mark_dependency(d, abs_fn)
  which throws:
  OSError: [Errno 2] No such file or directory: '/absolute-path/non-existent-file.inc'
  and parsing fails.
  Ad isfile() test for absolute fn and throw IOError to make
  resolve_file behavior consistent for both paths.

* I know we had some issues with -b relative-path-to-recipe.bb and
  absolute path, so consider this patch only as RFC and documentation of
  this problem

* Catch OSError too in ConfHandler.py:include() e.g. in case the file exists, but user
  cannot read it or something like that.

Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
process: Improve exit handling and hangs

It turns out we have a number of different ways the process server termination can
hang. If we call cancel_join_thread() on the event queue, it means that it can be left
containing partial data. This means the reading of the event queue in the terminate()
function can hang, the timeout and block parameters to Queue.get() don't make any
difference.

Equally, if we don't call cancel_join_thread(), the join_thread in terminate()
will hang giving a different deadlock.

The best solution I could find is to loop over the process is_alive() after requesting
it stops,  trying to join the thread and if that fails, try and flush the event
queue again.

It wasn't clear what difference a force option should make in this case, we're
gracefully trying to empty queues and shut down regardless of whether its a SIGTERM
so I've simply removed the force option.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
server/xmlrpc/prserv: Add sane timeout to default xmlrpc server

The standard python socket connect has long timouts which make sense for remote
connections but not local things like the PR Service. This adds a timeout
parameter to the common xmlrpc server creation function and sets it to a more
reasonable 5 seconds.

Making the PR server instantly exit is a good way to test the effect of this
on bitbake.

We can remove the bodged timeout in the PRServer terminate function which
has the side effect of affecting global scope.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
bitbake: Add ui event handlers filtering

Add functionality to allow UIs to update and change the types of events they
recieve. To do this we need to add a new command and also need to be able
to obtain the current event hander ID. In the case of xmlrpc, this is
straightforward, in the case of the process server we need to save the result
in a multiprocessing.Value() so we can retrive it. An excplit command
was added to the server API to facilitate this.

The same function can also be used to mask or unmask specific log messages,
allowing the UI to optionally differ from the standard set of message
filtering.

Based upon work by Cristiana Voicu <cristiana.voicu@intel.com>

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
data_smart: Add _remove operator

There are long standing complaints about the fact its very difficult
to remove a portion of a variable. The immediate request is for a -=
and =- operator. The trouble is that += and =+ are "immediate"
operators and are applied straight away. Most people would expect
-= and =- to be deferred to have the effect most people desire and
therefore implementing -= and =- would just make the situation more
confusing.

This deferred operation is much more similar to the override syntax
which happens at data store finalisation. The _remove operator is
therefore in keeping with the _append and _prepend operations.

This code is loosely based on a patch from Peter Seebach although it
has been rewritten to be simpler, more efficient and avoid some
potential bugs.

The code currently only works on space delimited variables, which
are by far the most commom type. If bitbake is ehanced to support
types natively in future, we can adjust this code to adapt to that.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>