WIP: modules/rust: add cbindgen helper

TODO: needs docs
TODO: needs tests
TODO: should we handle GeneratedSources?
TODO: should we add cpp-compat always?

mesonbuild/interpreter/interpreter.py

@@ -1,6 +1,6 @@
 # SPDX-License-Identifier: Apache-2.0
 # Copyright 2012-2021 The Meson development team
-# Copyright © 2023 Intel Corporation
+# Copyright © 2023-2024 Intel Corporation
 
 from __future__ import annotations
 
@@ -3090,6 +3090,10 @@ def source_strings_to_files(self, sources: T.List['SourceInputs'], strict: bool
     @T.overload
     def source_strings_to_files(self, sources: T.List[SourcesVarargsType], strict: bool = True) -> T.List['SourceOutputs']: ... # noqa: F811
 
+    @T.overload
+    def source_strings_to_files(self, sources: T.List[T.Union[mesonlib.FileOrString, build.CustomTarget, build.CustomTargetIndex, build.StructuredSources]], strict: bool = True) -> \
+        T.List[T.Union[mesonlib.File, build.CustomTarget, build.CustomTargetIndex, build.StructuredSources]]: ... # noqa: F811
+
     def source_strings_to_files(self, sources: T.List['SourceInputs'], strict: bool = True) -> T.List['SourceOutputs']: # noqa: F811
         """Lower inputs to a list of Targets and Files, replacing any strings.
 

mesonbuild/modules/rust.py

@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: Apache-2.0
-# Copyright © 2020-2023 Intel Corporation
+# Copyright © 2020-2024 Intel Corporation
 
 from __future__ import annotations
 import itertools
@@ -13,9 +13,9 @@
 from ..build import (BothLibraries, BuildTarget, CustomTargetIndex, Executable, ExtractedObjects, GeneratedList,
                      CustomTarget, InvalidArguments, Jar, StructuredSources, SharedLibrary)
 from ..compilers.compilers import are_asserts_disabled
-from ..interpreter.type_checking import DEPENDENCIES_KW, LINK_WITH_KW, SHARED_LIB_KWS, TEST_KWS, OUTPUT_KW, INCLUDE_DIRECTORIES, SOURCES_VARARGS
+from ..interpreter.type_checking import DEPENDENCIES_KW, LINK_WITH_KW, SHARED_LIB_KWS, TEST_KWS, OUTPUT_KW, INCLUDE_DIRECTORIES, SOURCES_VARARGS, in_set_validator
 from ..interpreterbase import ContainerTypeInfo, InterpreterException, KwargInfo, typed_kwargs, typed_pos_args, noPosargs, permittedKwargs
-from ..mesonlib import File
+from ..mesonlib import File, MesonException, version_compare
 
 if T.TYPE_CHECKING:
     from . import ModuleState
@@ -26,8 +26,9 @@
     from ..interpreter.interpreter import SourceInputs, SourceOutputs
     from ..programs import ExternalProgram, OverrideProgram
     from ..interpreter.type_checking import SourcesVarargsType
+    from ..utils.universal import FileOrString
 
-    from typing_extensions import TypedDict
+    from typing_extensions import Literal, TypedDict
 
     class FuncTest(_kwargs.BaseTest):
 
@@ -45,6 +46,19 @@ class FuncBindgen(TypedDict):
         output: str
         dependencies: T.List[T.Union[Dependency, ExternalLibrary]]
 
+    class FuncCBindgen(TypedDict):
+
+        config: str
+        language: Literal['c', 'cpp', 'cython']
+
+
+def _cbindgen_config_validator(val: str) -> T.Optional[str]:
+    if os.path.splitext(val) != '.toml':
+        return 'config file must be a .toml file'
+    if not os.path.exists(val):
+        return f'config file {val} doesn\'t exist'
+    return None
+
 
 class RustModule(ExtensionModule):
 
@@ -55,10 +69,13 @@ class RustModule(ExtensionModule):
     def __init__(self, interpreter: Interpreter) -> None:
         super().__init__(interpreter)
         self._bindgen_bin: T.Optional[T.Union[ExternalProgram, Executable, OverrideProgram]] = None
+        self._cbindgen_bin: T.Optional[T.Union[ExternalProgram, Executable, OverrideProgram]] = None
+        self._cbindgen_has_depfile = False
         self.methods.update({
             'test': self.test,
             'bindgen': self.bindgen,
             'proc_macro': self.proc_macro,
+            'cbindgen': self.cbindgen,
         })
 
     @typed_pos_args('rust.test', str, BuildTarget)
@@ -286,6 +303,73 @@ def proc_macro(self, state: ModuleState, args: T.Tuple[str, SourcesVarargsType],
         target = state._interpreter.build_target(state.current_node, args, kwargs, SharedLibrary)
         return target
 
+    @FeatureNew('rust.cbindgen', '1.3.0')
+    @typed_pos_args('rust.cbindgen', (File, StructuredSources, CustomTargetIndex, CustomTarget, str), str)
+    @typed_kwargs(
+        'rust.cbindgen',
+        KwargInfo('config', str, required=True, validator=_cbindgen_config_validator),
+        KwargInfo(
+            'language',
+            str,
+            default='c',
+            validator=in_set_validator({'c', 'cpp', 'cython'}),
+        ),
+        # TODO: depends
+        # TODO: depend_files
+    )
+    def cbindgen(self, state: ModuleState, args: T.Tuple[T.Union[FileOrString, CustomTarget, CustomTargetIndex, StructuredSources], str], kwargs: FuncCBindgen) -> ModuleReturnValue:
+        # TODO: should we allow GeneratedList here?
+
+        if self._cbindgen_bin is None:
+            self._cbindgen_bin = state.find_program('cbindgen')
+            self._cbindgen_has_depfile = version_compare(self._cbindgen_bin.get_version(self.interpreter), '>= 0.25')
+
+        _infile, outfile = args
+        infile = self.interpreter.source_strings_to_files([_infile])[0]
+
+        if isinstance(infile, StructuredSources):
+            infile = infile.first_file()
+            assert not isinstance(infile, GeneratedList), 'not yet? supported'
+            # TODO: need to depend on the rest of the StructuredSource
+
+        if isinstance(infile, File):
+            name = infile.fname
+        else:
+            assert not isinstance(infile, StructuredSources), "pyright understands this, but mypy doesn't"
+            name = infile.get_outputs()[0]
+            if len(infile.get_outputs()) != 1:
+                raise MesonException('Cannot pass a custom_target generating more than one output to rust.cbindgen, use custom_target[index] to select the output to generate bindings for')
+
+        if os.path.dirname(outfile):
+            raise InvalidArguments('outfile name must not contain a path segment')
+
+        # Set the --profile flag based on meson's debug option
+        debug = state.get_option('debug')
+        assert isinstance(debug, bool), 'for mypy'
+
+        # Convert Meson's `cpp` to cbindgen's `c++`
+        lang: str = kwargs['language']
+        if lang == 'cpp':
+            lang = 'c++'
+
+        command = [self._cbindgen_bin, '--output', '@OUTPUT@', '--config', '@INPUT0@', '--quiet', '--lang', lang, '--cpp-compat']
+        if self._cbindgen_has_depfile:
+            command.extend(['--depfile', '@DEPFILE@'])
+        command.extend(['--profile', 'debug' if debug else 'release'])
+
+        target = CustomTarget(
+            f'rustmod-cbindgen-{name}',
+            state.subdir,
+            state.subproject,
+            state.environment,
+            command,
+            [kwargs['config'], infile],
+            [outfile],
+            depfile=f'{name}.d',
+        )
+
+        return ModuleReturnValue(target, [target])
+
 
 def initialize(interp: Interpreter) -> RustModule:
     return RustModule(interp)