dependencies: add pybind11 custom factory

This works with pkg-config and cmake without any special support. The
custom factory adds further support for config-tool, via
`pybind11-config`. This is useful because the config-tool will work out
of the box when pybind11 is installed, but the pkg-config and cmake
files are shoved into python's site-packages, which is an unfortunate
distribution model and makes it impossible to use in an out of the box
manner.

It's possible to manually set up the PKG_CONFIG_PATH to detect it
anyway, but in case that does not happen, having the config-tool
fallback is extremely useful.

1 files changed, 23 insertions, 0 deletions

diff --git a/mesonbuild/dependencies/python.py b/mesonbuild/dependencies/python.py
index 478df6a..eaa9067 100644
--- a/mesonbuild/dependencies/python.py
+++ b/mesonbuild/dependencies/python.py
@@ -19,6 +19,8 @@ import typing as T
 
 from .. import mesonlib, mlog
 from .base import process_method_kw, DependencyMethods, DependencyTypeName, ExternalDependency, SystemDependency
+from .configtool import ConfigToolDependency
+from .factory import DependencyFactory
 from .framework import ExtraFrameworkDependency
 from .pkgconfig import PkgConfigDependency
 from ..environment import detect_cpu_family
@@ -49,6 +51,21 @@ else:
     _Base = object
 
 
+class Pybind11ConfigToolDependency(ConfigToolDependency):
+
+    tools = ['pybind11-config']
+
+    # pybind11 in 2.10.4 added --version, sanity-check another flag unique to it
+    # in the meantime
+    skip_version = '--pkgconfigdir'
+
+    def __init__(self, name: str, environment: Environment, kwargs: T.Dict[str, T.Any]):
+        super().__init__(name, environment, kwargs)
+        if not self.is_found:
+            return
+        self.compile_args = self.get_config_value(['--includes'], 'compile_args')
+
+
 class BasicPythonExternalProgram(ExternalProgram):
     def __init__(self, name: str, command: T.Optional[T.List[str]] = None,
                  ext_prog: T.Optional[ExternalProgram] = None):
@@ -371,3 +388,9 @@ def python_factory(env: 'Environment', for_machine: 'MachineChoice',
         candidates.append(functools.partial(PythonFrameworkDependency, 'Python', env, nkwargs, installation))
 
     return candidates
+
+pybind11_factory = DependencyFactory(
+    'pybind11',
+    [DependencyMethods.PKGCONFIG, DependencyMethods.CONFIG_TOOL, DependencyMethods.CMAKE],
+    configtool_class=Pybind11ConfigToolDependency,
+)