# Copyright (C) 2010 Chris Jerdonek (cjerdonek@webkit.org)

#

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"""Defines style error handler classes.

A style error handler is a function to call when a style error is

found. Style error handlers can also have state. A class that represents

a style error handler should implement the following methods.

Methods:

  __call__(self, line_number, category, confidence, message):

    Handle the occurrence of a style error.

    Check whether the error is reportable. If so, increment the total

    error count and report the details. Note that error reporting can

    be suppressed after reaching a certain number of reports.

    Args:

      line_number: The integer line number of the line containing the error.

      category: The name of the category of the error, for example

                "whitespace/newline".

      confidence: An integer between 1 and 5 inclusive that represents the

                  application's level of confidence in the error. The value

                  5 means that we are certain of the problem, and the

                  value 1 means that it could be a legitimate construct.

      message: The error message to report.

"""

import sys

class DefaultStyleErrorHandler(object):

    """The default style error handler."""

    def __init__(self, file_path, configuration, increment_error_count,

                 line_numbers=None):

        """Create a default style error handler.

        Args:

          file_path: The path to the file containing the error. This

                     is used for reporting to the user.

          configuration: A StyleProcessorConfiguration instance.

          increment_error_count: A function that takes no arguments and

                                 increments the total count of reportable

                                 errors.

          line_numbers: An array of line numbers of the lines for which

                        style errors should be reported, or None if errors

                        for all lines should be reported.  When it is not

                        None, this array normally contains the line numbers

                        corresponding to the modified lines of a patch.

        """

        if line_numbers is not None:

            line_numbers = set(line_numbers)

        self._file_path = file_path

        self._configuration = configuration

        self._increment_error_count = increment_error_count

        self._line_numbers = line_numbers

        # A string to integer dictionary cache of the number of reportable

        # errors per category passed to this instance.

        self._category_totals = {}

    # Useful for unit testing.

    def __eq__(self, other):

        """Return whether this instance is equal to another."""

        if self._configuration != other._configuration:

            return False

        if self._file_path != other._file_path:

            return False

        if self._increment_error_count != other._increment_error_count:

            return False

        if self._line_numbers != other._line_numbers:

            return False

        return True

    # Useful for unit testing.

    def __ne__(self, other):

        # Python does not automatically deduce __ne__ from __eq__.

        return not self.__eq__(other)

    def _add_reportable_error(self, category):

        """Increment the error count and return the new category total."""

        self._increment_error_count() # Increment the total.

        # Increment the category total.

        if not category in self._category_totals:

            self._category_totals[category] = 1

        else:

            self._category_totals[category] += 1

        return self._category_totals[category]

    def _max_reports(self, category):

        """Return the maximum number of errors to report."""

        if not category in self._configuration.max_reports_per_category:

            return None

        return self._configuration.max_reports_per_category[category]

    def __call__(self, line_number, category, confidence, message):

        """Handle the occurrence of a style error.

        See the docstring of this module for more information.

        """

        if (self._line_numbers is not None and

            line_number not in self._line_numbers):

            # Then the error occurred in a line that was not modified, so

            # the error is not reportable.

            return

        if not self._configuration.is_reportable(category=category,

                                                 confidence_in_error=confidence,

                                                 file_path=self._file_path):

            return

        category_total = self._add_reportable_error(category)

        max_reports = self._max_reports(category)

        if (max_reports is not None) and (category_total > max_reports):

            # Then suppress displaying the error.

            return

        self._configuration.write_style_error(category=category,

                                              confidence_in_error=confidence,

                                              file_path=self._file_path,

                                              line_number=line_number,

                                              message=message)

        if category_total == max_reports:

            self._configuration.stderr_write("Suppressing further [%s] reports "

                                             "for this file.\n" % category)