1 files changed, 227 insertions, 0 deletions
diff --git a/mesonbuild/dependencies/detect.py b/mesonbuild/dependencies/detect.py
new file mode 100644
index 0000000..4c7a477
--- /dev/null
+++ b/mesonbuild/dependencies/detect.py
@@ -0,0 +1,227 @@
+# Copyright 2013-2021 The Meson development team
+
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+
+#     http://www.apache.org/licenses/LICENSE-2.0
+
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+from __future__ import annotations
+
+from .base import ExternalDependency, DependencyException, DependencyMethods, NotFoundDependency
+from .cmake import CMakeDependency
+from .dub import DubDependency
+from .framework import ExtraFrameworkDependency
+from .pkgconfig import PkgConfigDependency
+
+from ..mesonlib import listify, MachineChoice, PerMachine
+from .. import mlog
+import functools
+import typing as T
+
+if T.TYPE_CHECKING:
+    from ..environment import Environment
+    from .factory import DependencyFactory, WrappedFactoryFunc, DependencyGenerator
+
+    TV_DepIDEntry = T.Union[str, bool, int, T.Tuple[str, ...]]
+    TV_DepID = T.Tuple[T.Tuple[str, TV_DepIDEntry], ...]
+
+# These must be defined in this file to avoid cyclical references.
+packages: T.Dict[
+    str,
+    T.Union[T.Type[ExternalDependency], 'DependencyFactory', 'WrappedFactoryFunc']
+] = {}
+_packages_accept_language: T.Set[str] = set()
+
+def get_dep_identifier(name: str, kwargs: T.Dict[str, T.Any]) -> 'TV_DepID':
+    identifier: 'TV_DepID' = (('name', name), )
+    from ..interpreter import permitted_dependency_kwargs
+    assert len(permitted_dependency_kwargs) == 19, \
+           'Extra kwargs have been added to dependency(), please review if it makes sense to handle it here'
+    for key, value in kwargs.items():
+        # 'version' is irrelevant for caching; the caller must check version matches
+        # 'native' is handled above with `for_machine`
+        # 'required' is irrelevant for caching; the caller handles it separately
+        # 'fallback' and 'allow_fallback' is not part of the cache because,
+        #     once a dependency has been found through a fallback, it should
+        #     be used for the rest of the Meson run.
+        # 'default_options' is only used in fallback case
+        # 'not_found_message' has no impact on the dependency lookup
+        # 'include_type' is handled after the dependency lookup
+        if key in {'version', 'native', 'required', 'fallback', 'allow_fallback', 'default_options',
+                   'not_found_message', 'include_type'}:
+            continue
+        # All keyword arguments are strings, ints, or lists (or lists of lists)
+        if isinstance(value, list):
+            for i in value:
+                assert isinstance(i, str)
+            value = tuple(frozenset(listify(value)))
+        else:
+            assert isinstance(value, (str, bool, int))
+        identifier = (*identifier, (key, value),)
+    return identifier
+
+display_name_map = {
+    'boost': 'Boost',
+    'cuda': 'CUDA',
+    'dub': 'DUB',
+    'gmock': 'GMock',
+    'gtest': 'GTest',
+    'hdf5': 'HDF5',
+    'llvm': 'LLVM',
+    'mpi': 'MPI',
+    'netcdf': 'NetCDF',
+    'openmp': 'OpenMP',
+    'wxwidgets': 'WxWidgets',
+}
+
+def find_external_dependency(name: str, env: 'Environment', kwargs: T.Dict[str, object]) -> T.Union['ExternalDependency', NotFoundDependency]:
+    assert name
+    required = kwargs.get('required', True)
+    if not isinstance(required, bool):
+        raise DependencyException('Keyword "required" must be a boolean.')
+    if not isinstance(kwargs.get('method', ''), str):
+        raise DependencyException('Keyword "method" must be a string.')
+    lname = name.lower()
+    if lname not in _packages_accept_language and 'language' in kwargs:
+        raise DependencyException(f'{name} dependency does not accept "language" keyword argument')
+    if not isinstance(kwargs.get('version', ''), (str, list)):
+        raise DependencyException('Keyword "Version" must be string or list.')
+
+    # display the dependency name with correct casing
+    display_name = display_name_map.get(lname, lname)
+
+    for_machine = MachineChoice.BUILD if kwargs.get('native', False) else MachineChoice.HOST
+
+    type_text = PerMachine('Build-time', 'Run-time')[for_machine] + ' dependency'
+
+    # build a list of dependency methods to try
+    candidates = _build_external_dependency_list(name, env, for_machine, kwargs)
+
+    pkg_exc: T.List[DependencyException] = []
+    pkgdep:  T.List[ExternalDependency] = []
+    details = ''
+
+    for c in candidates:
+        # try this dependency method
+        try:
+            d = c()
+            d._check_version()
+            pkgdep.append(d)
+        except DependencyException as e:
+            assert isinstance(c, functools.partial), 'for mypy'
+            bettermsg = f'Dependency lookup for {name} with method {c.func.log_tried()!r} failed: {e}'
+            mlog.debug(bettermsg)
+            e.args = (bettermsg,)
+            pkg_exc.append(e)
+        else:
+            pkg_exc.append(None)
+            details = d.log_details()
+            if details:
+                details = '(' + details + ') '
+            if 'language' in kwargs:
+                details += 'for ' + d.language + ' '
+
+            # if the dependency was found
+            if d.found():
+
+                info: mlog.TV_LoggableList = []
+                if d.version:
+                    info.append(mlog.normal_cyan(d.version))
+
+                log_info = d.log_info()
+                if log_info:
+                    info.append('(' + log_info + ')')
+
+                mlog.log(type_text, mlog.bold(display_name), details + 'found:', mlog.green('YES'), *info)
+
+                return d
+
+    # otherwise, the dependency could not be found
+    tried_methods = [d.log_tried() for d in pkgdep if d.log_tried()]
+    if tried_methods:
+        tried = mlog.format_list(tried_methods)
+    else:
+        tried = ''
+
+    mlog.log(type_text, mlog.bold(display_name), details + 'found:', mlog.red('NO'),
+             f'(tried {tried})' if tried else '')
+
+    if required:
+        # if an exception occurred with the first detection method, re-raise it
+        # (on the grounds that it came from the preferred dependency detection
+        # method)
+        if pkg_exc and pkg_exc[0]:
+            raise pkg_exc[0]
+
+        # we have a list of failed ExternalDependency objects, so we can report
+        # the methods we tried to find the dependency
+        raise DependencyException(f'Dependency "{name}" not found' +
+                                  (f', tried {tried}' if tried else ''))
+
+    return NotFoundDependency(name, env)
+
+
+def _build_external_dependency_list(name: str, env: 'Environment', for_machine: MachineChoice,
+                                    kwargs: T.Dict[str, T.Any]) -> T.List['DependencyGenerator']:
+    # First check if the method is valid
+    if 'method' in kwargs and kwargs['method'] not in [e.value for e in DependencyMethods]:
+        raise DependencyException('method {!r} is invalid'.format(kwargs['method']))
+
+    # Is there a specific dependency detector for this dependency?
+    lname = name.lower()
+    if lname in packages:
+        # Create the list of dependency object constructors using a factory
+        # class method, if one exists, otherwise the list just consists of the
+        # constructor
+        if isinstance(packages[lname], type):
+            entry1 = T.cast('T.Type[ExternalDependency]', packages[lname])  # mypy doesn't understand isinstance(..., type)
+            if issubclass(entry1, ExternalDependency):
+                func: T.Callable[[], 'ExternalDependency'] = functools.partial(entry1, env, kwargs)
+                dep = [func]
+        else:
+            entry2 = T.cast('T.Union[DependencyFactory, WrappedFactoryFunc]', packages[lname])
+            dep = entry2(env, for_machine, kwargs)
+        return dep
+
+    candidates: T.List['DependencyGenerator'] = []
+
+    # If it's explicitly requested, use the dub detection method (only)
+    if 'dub' == kwargs.get('method', ''):
+        candidates.append(functools.partial(DubDependency, name, env, kwargs))
+        return candidates
+
+    # If it's explicitly requested, use the pkgconfig detection method (only)
+    if 'pkg-config' == kwargs.get('method', ''):
+        candidates.append(functools.partial(PkgConfigDependency, name, env, kwargs))
+        return candidates
+
+    # If it's explicitly requested, use the CMake detection method (only)
+    if 'cmake' == kwargs.get('method', ''):
+        candidates.append(functools.partial(CMakeDependency, name, env, kwargs))
+        return candidates
+
+    # If it's explicitly requested, use the Extraframework detection method (only)
+    if 'extraframework' == kwargs.get('method', ''):
+        # On OSX, also try framework dependency detector
+        if env.machines[for_machine].is_darwin():
+            candidates.append(functools.partial(ExtraFrameworkDependency, name, env, kwargs))
+        return candidates
+
+    # Otherwise, just use the pkgconfig and cmake dependency detector
+    if 'auto' == kwargs.get('method', 'auto'):
+        candidates.append(functools.partial(PkgConfigDependency, name, env, kwargs))
+
+        # On OSX, also try framework dependency detector
+        if env.machines[for_machine].is_darwin():
+            candidates.append(functools.partial(ExtraFrameworkDependency, name, env, kwargs))
+
+        # Only use CMake as a last resort, since it might not work 100% (see #6113)
+        candidates.append(functools.partial(CMakeDependency, name, env, kwargs))
+
+    return candidates