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#
# WebKit's Python module for parsing and modifying ChangeLog files

import fileinput # inplace file editing for set_reviewer_in_changelog
import re
import textwrap


def view_source_url(revision_number):
    # FIMXE: This doesn't really belong in this file, but we don't have a
    # better home for it yet.
    # Maybe eventually a webkit_config.py?
    return "http://trac.webkit.org/changeset/%s" % revision_number


class ChangeLog:

    def __init__(self, path):
        self.path = path

    _changelog_indent = " " * 8

    # e.g. 2009-06-03  Eric Seidel  <eric@webkit.org>
    date_line_regexp = re.compile('^(\d{4}-\d{2}-\d{2})' # Consume the date.
                                + '\s+(.+)\s+' # Consume the name.
                                + '<([^<>]+)>$') # And the email address.

    @staticmethod
    def _parse_latest_entry_from_file(changelog_file):
        entry_lines = []
        # The first line should be a date line.
        first_line = changelog_file.readline()
        if not ChangeLog.date_line_regexp.match(first_line):
            return None
        entry_lines.append(first_line)

        for line in changelog_file:
            # If we've hit the next entry, return.
            if ChangeLog.date_line_regexp.match(line):
                # Remove the extra newline at the end
                return ''.join(entry_lines[:-1])
            entry_lines.append(line)
        return None # We never found a date line!

    def latest_entry(self):
        changelog_file = open(self.path)
        try:
            return self._parse_latest_entry_from_file(changelog_file)
        finally:
            changelog_file.close()

    # _wrap_line and _wrap_lines exist to work around
    # http://bugs.python.org/issue1859

    def _wrap_line(self, line):
        return textwrap.fill(line,
                             width=70,
                             initial_indent=self._changelog_indent,
                             # Don't break urls which may be longer than width.
                             break_long_words=False,
                             subsequent_indent=self._changelog_indent)

    # Workaround as suggested by guido in
    # http://bugs.python.org/issue1859#msg60040

    def _wrap_lines(self, message):
        lines = [self._wrap_line(line) for line in message.splitlines()]
        return "\n".join(lines)

    # This probably does not belong in changelogs.py
    def _message_for_revert(self, revision, reason, bug_url):
        message = "No review, rolling out r%s.\n" % revision
        message += "%s\n" % view_source_url(revision)
        if bug_url:
            message += "%s\n" % bug_url
        # Add an extra new line after the rollout links, before any reason.
        message += "\n"
        if reason:
            message += "%s\n\n" % reason
        return self._wrap_lines(message)

    def update_for_revert(self, revision, reason, bug_url=None):
        reviewed_by_regexp = re.compile(
                "%sReviewed by NOBODY \(OOPS!\)\." % self._changelog_indent)
        removing_boilerplate = False
        # inplace=1 creates a backup file and re-directs stdout to the file
        for line in fileinput.FileInput(self.path, inplace=1):
            if reviewed_by_regexp.search(line):
                message_lines = self._message_for_revert(revision,
                                                         reason,
                                                         bug_url)
                print reviewed_by_regexp.sub(message_lines, line),
                # Remove all the ChangeLog boilerplate between the Reviewed by
                # line and the first changed file.
                removing_boilerplate = True
            elif removing_boilerplate:
                if line.find('*') >= 0: # each changed file is preceded by a *
                    removing_boilerplate = False

            if not removing_boilerplate:
                print line,

    def set_reviewer(self, reviewer):
        # inplace=1 creates a backup file and re-directs stdout to the file
        for line in fileinput.FileInput(self.path, inplace=1):
            # Trailing comma suppresses printing newline
            print line.replace("NOBODY (OOPS!)", reviewer.encode("utf-8")),