Add a method to downgrade an option to disabled if it is not used.
This is useful to avoid unnecessary search for dependencies;
for example
dep = dependency('dep', required: get_option('feature').disable_auto_if(not foo))
can be used instead of the more verbose and complex
if get_option('feature').auto() and not foo then
dep = dependency('', required: false)
else
dep = dependency('dep', required: get_option('feature'))
endif
or to avoid unnecessary dependency searches:
dep1 = dependency('dep1', required: get_option('foo'))
# dep2 is only used together with dep1
dep2 = dependency('dep2', required: get_option('foo').disable_auto_if(not dep1.found()))
```
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Add a method to perform a logical AND on a feature object. The method
also takes care of raising an error if 'enabled' is ANDed with false.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This method simplifies the conversion of Feature objects to booleans.
Often, one has to use the "not" operator in order to treat "auto"
and "enabled" the same way.
"allowed()" also works well in conjunction with the require method that
is introduced in the next patch. For example,
if get_option('foo').require(host_machine.system() == 'windows').allowed() then
src += ['foo.c']
config.set10('HAVE_FOO', 1)
endif
can be used instead of
if host_machine.system() != 'windows'
if get_option('foo').enabled()
error('...')
endif
endif
if not get_option('foo').disabled() then
src += ['foo.c']
config.set10('HAVE_FOO', 1)
endif
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This is so dumb, we can just insert C for you without you having to know
that you're using C under the hood. This is nicer because:
1) Meson doesn't make the user add a language they're not explicitly
using
2) If there was ever an implementaiton of Vala that didn't use C as
it's assembly language, this wouldn't make any sense.
We need to escape space in variables that gets into cflags or libs
because otherwise we cannot split compiler args when paths contains
spaces. But custom variables are unlikely to be path that gets used in
cflags/libs, and escaping them cause regression in GStreamer that use
space as separator in a list variable.
"Stored by value" is more correct way to explain that example.
Mutable vs immutable means that you cannot mutate the value (e.g. list vs tuple in Python), and the example shows that `var2` is actually mutable.
Copying/storing a reference vs value is what what matters in the assignment, in Python `a=b` means `a` and `b` are references to the same list, while in meson `a=b` copies the value of `b` into `a`.
This will help facilitate cache busting in certain situations, and
replaces hand-rolled solutions of writing a length command to remove
various files/folders within the subprojects directory.
When using --reset we should guarantee that next reconfigure will pick
the latest code. For wrap-file we have no way to know if the revision
changed, so we have to delete the source tree and extract again.
It is unlikely that user has local changes in non-git subprojects, and
--reset is known to be dangerous.
Replace `meson compile scan-build` with `ninja -C dir scan-build`,
because scan-build target does not work with `meson compile`.
Note about SCANBUILD env variable was not precise enough to describe how
to pass arguments to scan-build - provide an example to make it clear.
Fixes: #7644.
Dylan Baker