1 files changed, 178 insertions, 0 deletions
diff --git a/meson/mesonbuild/dependencies/configtool.py b/meson/mesonbuild/dependencies/configtool.py
new file mode 100644
index 000000000..623affb2c
--- /dev/null
+++ b/meson/mesonbuild/dependencies/configtool.py
@@ -0,0 +1,178 @@
+# 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 .base import ExternalDependency, DependencyException, DependencyMethods, DependencyTypeName
+from ..mesonlib import listify, Popen_safe, split_args, version_compare, version_compare_many
+from ..programs import find_external_program
+from .. import mlog
+import re
+import typing as T
+
+from mesonbuild import mesonlib
+
+if T.TYPE_CHECKING:
+    from ..environment import Environment
+
+class ConfigToolDependency(ExternalDependency):
+
+    """Class representing dependencies found using a config tool.
+
+    Takes the following extra keys in kwargs that it uses internally:
+    :tools List[str]: A list of tool names to use
+    :version_arg str: The argument to pass to the tool to get it's version
+    :returncode_value int: The value of the correct returncode
+        Because some tools are stupid and don't return 0
+    """
+
+    tools: T.Optional[T.List[str]] = None
+    tool_name: T.Optional[str] = None
+    version_arg = '--version'
+    __strip_version = re.compile(r'^[0-9][0-9.]+')
+
+    def __init__(self, name: str, environment: 'Environment', kwargs: T.Dict[str, T.Any], language: T.Optional[str] = None):
+        super().__init__(DependencyTypeName('config-tool'), environment, kwargs, language=language)
+        self.name = name
+        # You may want to overwrite the class version in some cases
+        self.tools = listify(kwargs.get('tools', self.tools))
+        if not self.tool_name:
+            self.tool_name = self.tools[0]
+        if 'version_arg' in kwargs:
+            self.version_arg = kwargs['version_arg']
+
+        req_version_raw = kwargs.get('version', None)
+        if req_version_raw is not None:
+            req_version = mesonlib.stringlistify(req_version_raw)
+        else:
+            req_version = []
+        tool, version = self.find_config(req_version, kwargs.get('returncode_value', 0))
+        self.config = tool
+        self.is_found = self.report_config(version, req_version)
+        if not self.is_found:
+            self.config = None
+            return
+        self.version = version
+
+    def _sanitize_version(self, version: str) -> str:
+        """Remove any non-numeric, non-point version suffixes."""
+        m = self.__strip_version.match(version)
+        if m:
+            # Ensure that there isn't a trailing '.', such as an input like
+            # `1.2.3.git-1234`
+            return m.group(0).rstrip('.')
+        return version
+
+    def find_config(self, versions: T.List[str], returncode: int = 0) \
+            -> T.Tuple[T.Optional[T.List[str]], T.Optional[str]]:
+        """Helper method that searches for config tool binaries in PATH and
+        returns the one that best matches the given version requirements.
+        """
+        best_match: T.Tuple[T.Optional[T.List[str]], T.Optional[str]] = (None, None)
+        for potential_bin in find_external_program(
+                self.env, self.for_machine, self.tool_name,
+                self.tool_name, self.tools, allow_default_for_cross=False):
+            if not potential_bin.found():
+                continue
+            tool = potential_bin.get_command()
+            try:
+                p, out = Popen_safe(tool + [self.version_arg])[:2]
+            except (FileNotFoundError, PermissionError):
+                continue
+            if p.returncode != returncode:
+                continue
+
+            out = self._sanitize_version(out.strip())
+            # Some tools, like pcap-config don't supply a version, but also
+            # don't fail with --version, in that case just assume that there is
+            # only one version and return it.
+            if not out:
+                return (tool, None)
+            if versions:
+                is_found = version_compare_many(out, versions)[0]
+                # This allows returning a found version without a config tool,
+                # which is useful to inform the user that you found version x,
+                # but y was required.
+                if not is_found:
+                    tool = None
+            if best_match[1]:
+                if version_compare(out, '> {}'.format(best_match[1])):
+                    best_match = (tool, out)
+            else:
+                best_match = (tool, out)
+
+        return best_match
+
+    def report_config(self, version: T.Optional[str], req_version: T.List[str]) -> bool:
+        """Helper method to print messages about the tool."""
+
+        found_msg: T.List[T.Union[str, mlog.AnsiDecorator]] = [mlog.bold(self.tool_name), 'found:']
+
+        if self.config is None:
+            found_msg.append(mlog.red('NO'))
+            if version is not None and req_version:
+                found_msg.append(f'found {version!r} but need {req_version!r}')
+            elif req_version:
+                found_msg.append(f'need {req_version!r}')
+        else:
+            found_msg += [mlog.green('YES'), '({})'.format(' '.join(self.config)), version]
+
+        mlog.log(*found_msg)
+
+        return self.config is not None
+
+    def get_config_value(self, args: T.List[str], stage: str) -> T.List[str]:
+        p, out, err = Popen_safe(self.config + args)
+        if p.returncode != 0:
+            if self.required:
+                raise DependencyException(f'Could not generate {stage} for {self.name}.\n{err}')
+            return []
+        return split_args(out)
+
+    @staticmethod
+    def get_methods() -> T.List[DependencyMethods]:
+        return [DependencyMethods.AUTO, DependencyMethods.CONFIG_TOOL]
+
+    def get_configtool_variable(self, variable_name: str) -> str:
+        p, out, _ = Popen_safe(self.config + [f'--{variable_name}'])
+        if p.returncode != 0:
+            if self.required:
+                raise DependencyException(
+                    'Could not get variable "{}" for dependency {}'.format(
+                        variable_name, self.name))
+        variable = out.strip()
+        mlog.debug(f'Got config-tool variable {variable_name} : {variable}')
+        return variable
+
+    def log_tried(self) -> str:
+        return self.type_name
+
+    def get_variable(self, *, cmake: T.Optional[str] = None, pkgconfig: T.Optional[str] = None,
+                     configtool: T.Optional[str] = None, internal: T.Optional[str] = None,
+                     default_value: T.Optional[str] = None,
+                     pkgconfig_define: T.Optional[T.List[str]] = None) -> T.Union[str, T.List[str]]:
+        if configtool:
+            # In the not required case '' (empty string) will be returned if the
+            # variable is not found. Since '' is a valid value to return we
+            # set required to True here to force and error, and use the
+            # finally clause to ensure it's restored.
+            restore = self.required
+            self.required = True
+            try:
+                return self.get_configtool_variable(configtool)
+            except DependencyException:
+                pass
+            finally:
+                self.required = restore
+        if default_value is not None:
+            return default_value
+        raise DependencyException(f'Could not get config-tool variable and no default provided for {self!r}')