Meson has a common pattern of using 'if len(foo) == 0:' or
'if len(foo) != 0:', however, this is a common anti-pattern in python.
Instead tests for emptiness/non-emptiness should be done with a simple
'if foo:' or 'if not foo:'
Consider the following:
>>> import timeit
>>> timeit.timeit('if len([]) == 0: pass')
0.10730923599840025
>>> timeit.timeit('if not []: pass')
0.030033907998586074
>>> timeit.timeit('if len(['a', 'b', 'c', 'd']) == 0: pass')
0.1154778649979562
>>> timeit.timeit("if not ['a', 'b', 'c', 'd']: pass")
0.08259823200205574
>>> timeit.timeit('if len("") == 0: pass')
0.089759664999292
>>> timeit.timeit('if not "": pass')
0.02340641999762738
>>> timeit.timeit('if len("foo") == 0: pass')
0.08848102600313723
>>> timeit.timeit('if not "foo": pass')
0.04032287199879647
And for the one additional case of 'if len(foo.strip()) == 0', which can
be replaced with 'if not foo.isspace()'
>>> timeit.timeit('if len(" ".strip()) == 0: pass')
0.15294511600222904
>>> timeit.timeit('if " ".isspace(): pass')
0.09413968399894657
>>> timeit.timeit('if len(" abc".strip()) == 0: pass')
0.2023209120015963
>>> timeit.timeit('if " abc".isspace(): pass')
0.09571301700270851
In other words, it's always a win to not use len(), when you don't
actually want to check the length.
configure a detection method, for those types of dependencies that have
more than one means of detection.
The default detection methods are unchanged if 'method' is not
specified, and all dependencies support the method 'auto', which is the
same as not specifying a method.
The dependencies which do support multiple detection methods
additionally support other values, depending on the dependency.
When cross compiling with mingw it's problematic to assume that there is
a binary called windres, and having to set it via an environment
variable seems wrong when there is a handy cross-file for just such a
situation.
This patch allows setting windres in the [binaries] section of the cross
file. If the build is a cross build, then the windows module will check
for windres being set in the cross file before checking the WINDRES
environment variable or looking for a windres binary.
You can now pass a list of strings to the install_dir: kwarg to
build_target and custom_target.
Custom Targets:
===============
Allows you to specify the installation directory for each
corresponding output. For example:
custom_target('different-install-dirs',
output : ['first.file', 'second.file'],
...
install : true,
install_dir : ['somedir', 'otherdir])
This would install first.file to somedir and second.file to otherdir.
If only one install_dir is provided, all outputs are installed there
(same behaviour as before).
To only install some outputs, pass `false` for the outputs that you
don't want installed. For example:
custom_target('only-install-second',
output : ['first.file', 'second.file'],
...
install : true,
install_dir : [false, 'otherdir])
This would install second.file to otherdir and not install first.file.
Build Targets:
==============
With build_target() (which includes executable(), library(), etc),
usually there is only one primary output. However some types of
targets have multiple outputs.
For example, while generating Vala libraries, valac also generates
a header and a .vapi file both of which often need to be installed.
This allows you to specify installation directories for those too.
# This will only install the library (same as before)
shared_library('somevalalib', 'somesource.vala',
...
install : true)
# This will install the library, the header, and the vapi into the
# respective directories
shared_library('somevalalib', 'somesource.vala',
...
install : true,
install_dir : ['libdir', 'incdir', 'vapidir'])
# This will install the library into the default libdir and
# everything else into the specified directories
shared_library('somevalalib', 'somesource.vala',
...
install : true,
install_dir : [true, 'incdir', 'vapidir'])
# This will NOT install the library, and will install everything
# else into the specified directories
shared_library('somevalalib', 'somesource.vala',
...
install : true,
install_dir : [false, 'incdir', 'vapidir'])
true/false can also be used for secondary outputs in the same way.
Valac can also generate a GIR file for libraries when the `vala_gir:`
keyword argument is passed to library(). In that case, `install_dir:`
must be given a list with four elements, one for each output.
Includes tests for all these.
Closes https://github.com/mesonbuild/meson/issues/705
Closes https://github.com/mesonbuild/meson/issues/891
Closes https://github.com/mesonbuild/meson/issues/892
Closes https://github.com/mesonbuild/meson/issues/1178
Closes https://github.com/mesonbuild/meson/issues/1193
This avoids unnecessary rebuilds occuring when Meson regenerates the
build.ninja file. Previously, if the ordering of the commandline
arguments changed then Ninja would consider the outputs dirty and
rebuild them.
There is no need to do obj.get_command() and in fact it's wrong
because the VS backends need to resolve each object to absolute paths
and get_command() does not do that.
This should fix invocation of GNOME module helpers with the VS backends
For the record, absolute paths for programs are needed because the
same PATH environment won't necessarily be available to Visual Studio
when it builds the generated solution.
Related to https://github.com/mesonbuild/meson/issues/1419
This used to produce a warning, but then would crash anyway. It's
simpler if we just error out and have the user disable gir generation or
install gobject-introspection.
We can't support generated XML files with custom_target() because the
dependency scanning happens at configure time, but we *can* support
generating them with configure_file().
Closes https://github.com/mesonbuild/meson/issues/1380
We don't need dependencies to work correctly to use the output of
configure_file in the dependencies: kwarg.
This allows GNOME Recipes to built without the latest glib git.
Ever since we changed how we do library searching, the full path to the
library has not been available under `.fullpath`. This has been broken
for at least a year...
And actually test that prog.path() works. The earlier test was just
running the command without checking if it succeeded.
Also make everything use prog.get_command() or get_path() instead of
accessing the internal member prog.fullpath directly.
Set the rules for the symlinking on the target itself, and then reuse
that information while generating aliases during the build, and then
pass it to the install script too.
Cache the absolute dir that the script is searched in and the name of
the script. These are the only two things that change.
Update the test to test for both #1235 and the case when a script of the
same name is in a different directory (which also covers the subproject
case).
Closes#1235
Dylan Baker
Patrick Griffis
Jussi Pakkanen
Richard Hughes
Aaron Small
Nirbheek Chauhan
Sam Thursfield
Tim-Philipp Müller
Elliott Sales de Andrade
Thibault Saunier
Mike Sinkovsky
Igor Gnatenko