LinterBase

Complexity

Total Complexity

47

Size/Duplication

Total Lines	397
Duplicated Lines	0 %

Importance

Changes	5
Bugs	0	Features	0

from contextlib import contextmanager
    class LinterBase(LocalBear, metaclass=LinterMeta):

        @staticmethod
        def generate_config(filename, file):
            """
            Generates the content of a config-file the linter-tool might need.

            The contents generated from this function are written to a
            temporary file and the path is provided inside
            ``create_arguments()``.

            By default no configuration is generated.

            You can provide additional keyword arguments and defaults. These
            will be interpreted as required settings that need to be provided
            through a coafile-section.

            :param filename:
                The name of the file currently processed.
            :param file:
                The contents of the file currently processed.
            :return:
                The config-file-contents as a string or ``None``.
            """
            return None

        @staticmethod
        def create_arguments(filename, file, config_file):
            """
            Creates the arguments for the linter.

            You can provide additional keyword arguments and defaults. These
            will be interpreted as required settings that need to be provided
            through a coafile-section.

            :param filename:
                The name of the file the linter-tool shall process.
            :param file:
                The contents of the file.
            :param config_file:
                The path of the config-file if used. ``None`` if unused.
            :return:
                A sequence of arguments to feed the linter-tool with.
            """
            raise NotImplementedError

        @staticmethod
        def get_executable():
            """
            Returns the executable of this class.

            :return:
                The executable name.
            """
            return options["executable"]

        @classmethod
        def check_prerequisites(cls):
            """
            Checks whether the linter-tool the bear uses is operational.

            :return:
                True if operational, otherwise a string containing more info.
            """
            if shutil.which(cls.get_executable()) is None:
                return (repr(cls.get_executable()) + " is not installed." +
                        (" " + options["executable_check_fail_info"]
                         if options["executable_check_fail_info"] else
                         ""))
            else:
                if options["prerequisite_check_command"]:
                    try:
                        check_call(options["prerequisite_check_command"],
                                   stdout=DEVNULL,
                                   stderr=DEVNULL)
                        return True
                    except (OSError, CalledProcessError):
                        return options["prerequisite_check_fail_message"]
                return True

        @classmethod
        def _get_create_arguments_metadata(cls):
            return FunctionMetadata.from_function(
                cls.create_arguments,
                omit={"self", "filename", "file", "config_file"})

        @classmethod
        def _get_generate_config_metadata(cls):
            return FunctionMetadata.from_function(
                cls.generate_config,
                omit={"filename", "file"})

        @classmethod
        def _get_process_output_metadata(cls):
            metadata = FunctionMetadata.from_function(cls.process_output)

            if options["output_format"] is None:
                omitted = {"self", "output", "filename", "file"}
            else:
                # If a specific output format is provided, function signatures
                # from process_output functions should not appear in the help.
                omitted = set(chain(metadata.non_optional_params,
                                    metadata.optional_params))

            metadata.omit = omitted
            return metadata

        @classmethod
        def get_metadata(cls):
            merged_metadata = FunctionMetadata.merge(
                cls._get_process_output_metadata(),
                cls._get_generate_config_metadata(),
                cls._get_create_arguments_metadata())
            merged_metadata.desc = inspect.getdoc(cls)
            return merged_metadata

        def _convert_output_regex_match_to_result(self,
                                                  match,
                                                  filename,
                                                  severity_map,
                                                  result_message):
            """
            Converts the matched named-groups of ``output_regex`` to an actual
            ``Result``.

            :param match:
                The regex match object.
            :param filename:
                The name of the file this match belongs to.
            :param severity_map:
                The dict to use to map the severity-match to an actual
                ``RESULT_SEVERITY``.
            :param result_message:
                The static message to use for results instead of grabbing it
                from the executable output via the ``message`` named regex
                group.
            """
            # Pre process the groups
            groups = match.groupdict()

            if 'severity' in groups:
                try:
                    groups["severity"] = severity_map[
                        groups["severity"].lower()]
                except KeyError:
                    self.warn(
                        repr(groups["severity"]) + " not found in "
                        "severity-map. Assuming `RESULT_SEVERITY.NORMAL`.")
                    groups["severity"] = RESULT_SEVERITY.NORMAL
            else:
                groups['severity'] = RESULT_SEVERITY.NORMAL

            for variable in ("line", "column", "end_line", "end_column"):
                groups[variable] = (None
                                    if groups.get(variable, None) is None else
                                    int(groups[variable]))

            if "origin" in groups:
                groups["origin"] = "{} ({})".format(klass.__name__,
                                                    groups["origin"].strip())

            # Construct the result.
            return Result.from_values(
                origin=groups.get("origin", self),
                message=(groups.get("message", "").strip()
                         if result_message is None else result_message),
                file=filename,
                severity=groups["severity"],
                line=groups["line"],
                column=groups["column"],
                end_line=groups["end_line"],
                end_column=groups["end_column"],
                additional_info=groups.get("additional_info", "").strip())

        def process_output_corrected(self,
                                     output,
                                     filename,
                                     file,
                                     diff_severity=RESULT_SEVERITY.NORMAL,
                                     result_message="Inconsistency found.",
                                     diff_distance=1):
            """
            Processes the executable's output as a corrected file.

            :param output:
                The output of the program. This can be either a single
                string or a sequence of strings.
            :param filename:
                The filename of the file currently being corrected.
            :param file:
                The contents of the file currently being corrected.
            :param diff_severity:
                The severity to use for generating results.
            :param result_message:
                The message to use for generating results.
            :param diff_distance:
                Number of unchanged lines that are allowed in between two
                changed lines so they get yielded as one diff. If a negative
                distance is given, every change will be yielded as an own diff,
                even if they are right beneath each other.
            :return:
                An iterator returning results containing patches for the
                file to correct.
            """
            if isinstance(output, str):
                output = (output,)

            for string in output:
                for diff in Diff.from_string_arrays(
                        file,
                        string.splitlines(keepends=True)).split_diff(
                            distance=diff_distance):
                    yield Result(self,
                                 result_message,
                                 affected_code=diff.affected_code(filename),
                                 diffs={filename: diff},
                                 severity=diff_severity)

        def process_output_regex(
                self, output, filename, file, output_regex,
                severity_map=MappingProxyType({
                    "critical": RESULT_SEVERITY.MAJOR,
                    "c": RESULT_SEVERITY.MAJOR,
                    "fatal": RESULT_SEVERITY.MAJOR,
                    "fail": RESULT_SEVERITY.MAJOR,
                    "f": RESULT_SEVERITY.MAJOR,
                    "error": RESULT_SEVERITY.MAJOR,
                    "err": RESULT_SEVERITY.MAJOR,
                    "e": RESULT_SEVERITY.MAJOR,
                    "warning": RESULT_SEVERITY.NORMAL,
                    "warn": RESULT_SEVERITY.NORMAL,
                    "w": RESULT_SEVERITY.NORMAL,
                    "information": RESULT_SEVERITY.INFO,
                    "info": RESULT_SEVERITY.INFO,
                    "i": RESULT_SEVERITY.INFO,
                    "suggestion": RESULT_SEVERITY.INFO}),
                result_message=None):
            """
            Processes the executable's output using a regex.

            :param output:
                The output of the program. This can be either a single
                string or a sequence of strings.
            :param filename:
                The filename of the file currently being corrected.
            :param file:
                The contents of the file currently being corrected.
            :param output_regex:
                The regex to parse the output with. It should use as many
                of the following named groups (via ``(?P<name>...)``) to
                provide a good result:

                - line - The line where the issue starts.
                - column - The column where the issue starts.
                - end_line - The line where the issue ends.
                - end_column - The column where the issue ends.
                - severity - The severity of the issue.
                - message - The message of the result.
                - origin - The origin of the issue.
                - additional_info - Additional info provided by the issue.

                The groups ``line``, ``column``, ``end_line`` and
                ``end_column`` don't have to match numbers only, they can
                also match nothing, the generated ``Result`` is filled
                automatically with ``None`` then for the appropriate
                properties.
            :param severity_map:
                A dict used to map a severity string (captured from the
                ``output_regex`` with the named group ``severity``) to an
                actual ``coalib.results.RESULT_SEVERITY`` for a result.
            :param result_message:
                The static message to use for results instead of grabbing it
                from the executable output via the ``message`` named regex
                group.
            :return:
                An iterator returning results.
            """
            if isinstance(output, str):
                output = (output,)

            for string in output:
                for match in re.finditer(output_regex, string):
                    yield self._convert_output_regex_match_to_result(
                        match, filename, severity_map=severity_map,
                        result_message=result_message)

        if options["output_format"] is None:
            # Check if user supplied a `process_output` override.
            if not callable(getattr(klass, "process_output", None)):
                raise ValueError("`process_output` not provided by given "
                                 "class {!r}.".format(klass.__name__))
                # No need to assign to `process_output` here, the class mixing
                # below automatically does that.
        else:
            # Prevent people from accidentally defining `process_output`
            # manually, as this would implicitly override the internally
            # set-up `process_output`.
            if hasattr(klass, "process_output"):
                raise ValueError("Found `process_output` already defined "
                                 "by class {!r}, but {!r} output-format is "
                                 "specified.".format(klass.__name__,
                                                     options["output_format"]))

            if options["output_format"] == "corrected":
                process_output_args = {
                    key: options[key]
                    for key in ("result_message", "diff_severity",
                                "diff_distance")
                    if key in options}

                process_output = partialmethod(
                    process_output_corrected, **process_output_args)

            else:
                assert options["output_format"] == "regex"

                process_output_args = {
                    key: options[key]
                    for key in ("output_regex", "severity_map",
                                "result_message")
                    if key in options}

                process_output = partialmethod(
                    process_output_regex, **process_output_args)

        @classmethod
        @contextmanager
        def _create_config(cls, filename, file, **kwargs):
            """
            Provides a context-manager that creates the config file if the
            user provides one and cleans it up when done with linting.

            :param filename:
                The filename of the file.
            :param file:
                The file contents.
            :param kwargs:
                Section settings passed from ``run()``.
            :return:
                A context-manager handling the config-file.
            """
            content = cls.generate_config(filename, file, **kwargs)
            if content is None:
                yield None
            else:
                with make_temp(
                        suffix=options["config_suffix"]) as config_file:
                    with open(config_file, mode="w") as fl:
                        fl.write(content)
                    yield config_file

        def run(self, filename, file, **kwargs):
            # Get the **kwargs params to forward to `generate_config()`
            # (from `_create_config()`).
            generate_config_kwargs = FunctionMetadata.filter_parameters(
                self._get_generate_config_metadata(), kwargs)

            with self._create_config(
                    filename,
                    file,
                    **generate_config_kwargs) as config_file:
                # And now retrieve the **kwargs for `create_arguments()`.
                create_arguments_kwargs = (
                    FunctionMetadata.filter_parameters(
                        self._get_create_arguments_metadata(), kwargs))

                args = self.create_arguments(filename, file, config_file,
                                             **create_arguments_kwargs)

                try:
                    args = tuple(args)
                except TypeError:
                    self.err("The given arguments "
                             "{!r} are not iterable.".format(args))
                    return

                arguments = (self.get_executable(),) + args
                self.debug("Running '{}'".format(' '.join(arguments)))

                output = run_shell_command(
                    arguments,
                    stdin="".join(file) if options["use_stdin"] else None)

                output = tuple(compress(
                    output,
                    (options["use_stdout"], options["use_stderr"])))
                if len(output) == 1:
                    output = output[0]

                process_output_kwargs = FunctionMetadata.filter_parameters(
                    self._get_process_output_metadata(), kwargs)
                return self.process_output(output, filename, file,
                                           **process_output_kwargs)

        def __repr__(self):
            return "<{} linter object (wrapping {!r}) at {}>".format(
                type(self).__name__, self.get_executable(), hex(id(self)))