Since the underlying issues with the Python bindings are now fixed,
in most cases we can safely default to allowing an algorithm to
run in a background thread!!
So now we make this the default, and require individual algorithms
which are NOT thread safe to declare this. This includes algorithms
which directly manipulate the current project or layers (such as
setting layer styles), alter the selections in layers, or which
rely on 3rd party libraries (for now, SAGA and GRASS algorithms
are marked as not thread safe... TODO - someone more familiar with
these libraries can investigate and remove the flag if appropriate).
Also models are marked as non-thread safe. TODO: only flag an
individual model as thread-unsafe if any of its child algorithms
report this flag.
And make this support opt-out, since the vast majority of providers
are based on QGIS API and don't have external dependencies which would
restrict use of memory layers/etc.
Plus, I'd rather see non-compliant providers expose this support when
they can't use non-file-based-outputs (and make this the bug which
needs fixing) then have to rely on plugin providers to discover and
explicitly expose this support.
options should be available for certain model outputs and script
algorithm outputs
We do this by swapping the test for non-file based output support
from checking only the algorithm's provider to instead checking
on a parameter-by-parameter basis.
This is done in order to support models. For models, depending
on what child algorithm a model output is based off, an individual
model may or may not have support for non-file based outputs. E.g
a model may generate outputs from a native qgis alg (supporting
these outputs) AND an output from a GDAL alg (with no support
for these outputs). In this case we need to enable or disable
the ui controls for non-file based outputs on an individual
output basis.
For scripts (for now) we blindly just say all outputs support
non-file based formats. This is going to be the case most of
the time, since scripts will usually be written using PyQGIS
API. For the exceptions (e.g. scripts which call other algs
like GDAL algs) we probably should add some way for the script
to indicate whether an individual output supports this, but
for now we just say they all do.
Fixes#17949
I realise this adds another toolbar button... but I'd strongly
argue that the toolbox is used FAR FAR more often than many of the
other toolbar actions!
Brings the behaviour into line with the styling dock, where
the action is checkable and checked only when the toolbox
is open AND user visible (i.e. not hidden behind another tab). If
the toolbox is open but hidden, then hitting the Toolbox action
brings it to the front tab.
Otherwise it's often necessary to hit to Toolbox shortcut twice -
once to close a hidden toolbox tab, and a second time to open
and raise it.
