#!/usr/bin/env python

# See usage() for details, or run with --help option.
#
#          .-------------------------------------------------.
#          |  "An ad hoc format deserves an ad hoc parser."  |
#          `-------------------------------------------------'
#
# Some Subversion project log messages include parseable data to help
# track who's contributing what.  The exact syntax is described in
# hacking.html#crediting, but here's an example, indented by three
# spaces, i.e., the "Patch by:" starts at the beginning of a line:
#
#    Patch by: David Anderson <david.anderson@calixo.net>
#              <justin@erenkrantz.com>
#              me
#    (I wrote the regression tests.)
#    Found by: Phineas T. Phinder <phtph@ph1nderz.com>
#    Suggested by: Snosbig Q. Ptermione <sqptermione@example.com>
#    Review by: Justin Erenkrantz <justin@erenkrantz.com>
#               rooneg
#    (They caught an off-by-one error in the main loop.)
#
# This is a pathological example, but it shows all the things we might
# need to parse.  We need to:
#
#   - Detect the officially-approved "WORD by: " fields.
#   - Grab every name (one per line) in each field.
#   - Handle names in various formats, unifying where possible.
#   - Expand "me" to the committer name for this revision.
#   - Associate a parenthetical aside following a field with that field.
#
# NOTES: You might be wondering, why not take 'svn log --xml' input?
# Well, that would be the Right Thing to do, but in practice this was
# a lot easier to whip up for straight 'svn log' output.  I'd have no
# objection to it being rewritten to take XML input.

import os
import sys
import re
import getopt
try:
  my_getopt = getopt.gnu_getopt
except AttributeError:
  my_getopt = getopt.getopt
try:
  # Python >=3.0
  from urllib.parse import quote as urllib_parse_quote
except ImportError:
  # Python <3.0
  from urllib import quote as urllib_parse_quote


# Warnings and errors start with these strings.  They are typically
# followed by a colon and a space, as in "%s: " ==> "WARNING: ".
warning_prefix = 'WARNING'
error_prefix = 'ERROR'

def complain(msg, fatal=False):
  """Print MSG as a warning, or if FATAL is true, print it as an error
  and exit."""
  prefix = 'WARNING: '
  if fatal:
    prefix = 'ERROR: '
  sys.stderr.write(prefix + msg + '\n')
  if fatal:
    sys.exit(1)


def html_spam_guard(addr, entities_only=False):
  """Return a spam-protected version of email ADDR that renders the
  same in HTML as the original address.  If ENTITIES_ONLY, use a less
  thorough mangling scheme involving entities only, avoiding the use
  of tags."""
  if entities_only:
    def mangle(x):
      return "&#%d;" % ord (x)
  else:
    def mangle(x):
      return "<span>&#%d;</span>" % ord(x)
  return "".join(map(mangle, addr))


def escape_html(str):
  """Return an HTML-escaped version of STR."""
  return str.replace('&', '&amp;').replace('<', '&lt;').replace('>', '&gt;')


_spam_guard_in_html_block_re = re.compile(r'&lt;([^&]*@[^&]*)&gt;')
def _spam_guard_in_html_block_func(m):
  return "&lt;%s&gt;" % html_spam_guard(m.group(1))
def spam_guard_in_html_block(str):
  """Take a block of HTML data, and run html_spam_guard() on parts of it."""
  return _spam_guard_in_html_block_re.subn(_spam_guard_in_html_block_func,
                                           str)[0]

def html_header(title, page_heading=None, highlight_targets=False):
  """Write HTML file header.  TITLE and PAGE_HEADING parameters are
  expected to already by HTML-escaped if needed.  If HIGHLIGHT_TARGETS
is true, then write out a style header that causes anchor targets to be
surrounded by a red border when they are jumped to."""
  if not page_heading:
    page_heading = title
  s  = '<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"\n'
  s += ' "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">\n'
  s += '<html><head>\n'
  s += '<meta http-equiv="Content-Type"'
  s += ' content="text/html; charset=UTF-8" />\n'
  if highlight_targets:
    s += '<style type="text/css">\n'
    s += ':target { border: 2px solid red; }\n'
    s += '</style>\n'
  s += '<title>%s</title>\n' % title
  s += '</head>\n\n'
  s += '<body style="text-color: black; background-color: white">\n\n'
  s += '<h1 style="text-align: center">%s</h1>\n\n' % page_heading
  s += '<hr />\n\n'
  return s


def html_footer():
  return '\n</body>\n</html>\n'


class Contributor:
  # Map contributor names to contributor instances, so that there
  # exists exactly one instance associated with a given name.
  # Fold names with email addresses.  That is, if we see someone
  # listed first with just an email address, but later with a real
  # name and that same email address together, we create only one
  # instance, and store it under both the email and the real name.
  all_contributors = { }

  # See __hash__() for why this is necessary.
  hash_value = 1

  def __init__(self, username, real_name, email):
    """Instantiate a contributor.  Don't use this to generate a
    Contributor for an external caller, though, use .get() instead."""
    self.real_name = real_name
    self.username  = username
    self.email     = email
    self.is_committer = False       # Assume not until hear otherwise.
    self.is_full_committer = False  # Assume not until hear otherwise.
    # Map verbs (e.g., "Patch", "Suggested", "Review") to lists of
    # LogMessage objects.  For example, the log messages stored under
    # "Patch" represent all the revisions for which this contributor
    # contributed a patch.
    self.activities = { }
    # Sigh.
    self.unique_hash_value = Contributor.hash_value
    Contributor.hash_value += 1

  def add_activity(self, field_name, log):
    """Record that this contributor was active in FIELD_NAME in LOG."""
    logs = self.activities.get(field_name)
    if not logs:
      logs = [ ]
      self.activities[field_name] = logs
    if not log in logs:
      logs.append(log)

  @staticmethod
  def get(username, real_name, email):
    """If this contributor is already registered, just return it;
    otherwise, register it then return it.  Hint: use parse() to
    generate the arguments."""
    c = None
    for key in username, real_name, email:
      if key and key in Contributor.all_contributors:
        c = Contributor.all_contributors[key]
        break
    # If we didn't get a Contributor, create one now.
    if not c:
      c = Contributor(username, real_name, email)
    # If we know identifying information that the Contributor lacks,
    # then give it to the Contributor now.
    if username:
      if not c.username:
        c.username = username
      Contributor.all_contributors[username]  = c
    if real_name:
      if not c.real_name:
        c.real_name = real_name
      Contributor.all_contributors[real_name] = c
    if email:
      if not c.email:
        c.email = email
      Contributor.all_contributors[email]     = c
    # This Contributor has never been in better shape; return it.
    return c

  def score(self):
    """Return a contribution score for this contributor."""
    # Right now we count a patch as 2, anything else as 1.
    score = 0
    for activity in self.activities.keys():
      if activity == 'Patch':
        score += len(self.activities[activity]) * 2
      else:
        score += len(self.activities[activity])
    return score

  def score_str(self):
    """Return a contribution score HTML string for this contributor."""
    patch_score = 0
    other_score = 0
    for activity in self.activities.keys():
      if activity == 'Patch':
        patch_score += len(self.activities[activity])
      else:
        other_score += len(self.activities[activity])
    if patch_score == 0:
      patch_str = ""
    elif patch_score == 1:
      patch_str = "1&nbsp;patch"
    else:
      patch_str = "%d&nbsp;patches" % patch_score
    if other_score == 0:
      other_str = ""
    elif other_score == 1:
      other_str = "1&nbsp;non-patch"
    else:
      other_str = "%d&nbsp;non-patches" % other_score
    if patch_str:
      if other_str:
        return ",&nbsp;".join((patch_str, other_str))
      else:
        return patch_str
    else:
      return other_str

  def __cmp__(self, other):
    if self.is_full_committer and not other.is_full_committer:
      return 1
    if other.is_full_committer and not self.is_full_committer:
      return -1
    result = cmp(self.score(), other.score())
    if result == 0:
      return cmp(self.big_name(), other.big_name())
    else:
      return 0 - result

  def __hash__(self):
    """See LogMessage.__hash__() for why this exists."""
    return self.hash_value

  @staticmethod
  def parse(name):
    """Parse NAME, which can be

       - A committer username, or
       - A space-separated real name, or
       - A space-separated real name followed by an email address in
           angle brackets, or
       - Just an email address in angle brackets.

     (The email address may have '@' disguised as '{_AT_}'.)

     Return a tuple of (committer_username, real_name, email_address)
     any of which can be None if not available in NAME."""
    username  = None
    real_name = None
    email     = None
    name_components = name.split()
    if len(name_components) == 1:
      name = name_components[0] # Effectively, name = name.strip()
      if name[0] == '<' and name[-1] == '>':
        email = name[1:-1]
      elif name.find('@') != -1 or name.find('{_AT_}') != -1:
        email = name
      else:
        username = name
    elif name_components[-1][0] == '<' and name_components[-1][-1] == '>':
      real_name = ' '.join(name_components[0:-1])
      email = name_components[-1][1:-1]
    else:
      real_name = ' '.join(name_components)

    if email is not None:
      # We unobfuscate here and work with the '@' internally, since
      # we'll obfuscate it again (differently) before writing it out.
      email = email.replace('{_AT_}', '@')

    return username, real_name, email

  def canonical_name(self):
    """Return a canonical name for this contributor.  The canonical
    name may or may not be based on the contributor's actual email
    address.

    The canonical name will not contain filename-unsafe characters.

    This method is guaranteed to return the same canonical name every
    time only if no further contributions are recorded from this
    contributor after the first call.  This is because a contribution
    may bring a new form of the contributor's name, one which affects
    the algorithm used to construct canonical names."""
    retval = None
    if self.username:
      retval = self.username
    elif self.email:
      # Take some rudimentary steps to shorten the email address, to
      # make it more manageable.  If this is ever discovered to result
      # in collisions, we can always just use to the full address.
      try:
        at_posn = self.email.index('@')
        first_dot_after_at = self.email.index('.', at_posn)
        retval = self.email[0:first_dot_after_at]
      except ValueError:
        retval = self.email
    elif self.real_name:
      # Last resort: construct canonical name based on real name.
      retval = ''.join(self.real_name.lower().split(' '))
    if retval is None:
      complain('Unable to construct a canonical name for Contributor.', True)
    return urllib_parse_quote(retval, safe="!#$&'()+,;<=>@[]^`{}~")

  def big_name(self, html=False, html_eo=False):
    """Return as complete a name as possible for this contributor.
    If HTML, then call html_spam_guard() on email addresses.
    If HTML_EO, then do the same, but specifying entities_only mode."""
    html = html or html_eo
    name_bits = []
    if self.real_name:
      if html:
        name_bits.append(escape_html(self.real_name))
      else:
        name_bits.append(self.real_name)
    if self.email:
      if not self.real_name and not self.username:
        name_bits.append(self.email)
      elif html:
        name_bits.append("&lt;%s&gt;" % html_spam_guard(self.email, html_eo))
      else:
        name_bits.append("<%s>" % self.email)
    if self.username:
      if not self.real_name and not self.email:
        name_bits.append(self.username)
      else:
        name_bits.append("(%s)" % self.username)
    return " ".join(name_bits)

  def __str__(self):
    s = 'CONTRIBUTOR: '
    s += self.big_name()
    s += "\ncanonical name: '%s'" % self.canonical_name()
    if len(self.activities) > 0:
      s += '\n   '
    for activity in self.activities.keys():
      val = self.activities[activity]
      s += '[%s:' % activity
      for log in val:
        s += ' %s' % log.revision
      s += ']'
    return s

  def html_out(self, revision_url_pattern, filename):
    """Create an HTML file named FILENAME, showing all the revisions in which
    this contributor was active."""
    out = open(filename, 'w')
    out.write(html_header(self.big_name(html_eo=True),
                          self.big_name(html=True), True))
    unique_logs = { }

    sorted_activities = sorted(self.activities.keys())

    out.write('<div class="h2" id="activities" title="activities">\n\n')
    out.write('<table border="1">\n')
    out.write('<tr>\n')
    for activity in sorted_activities:
      out.write('<td>%s</td>\n\n' % activity)
    out.write('</tr>\n')
    out.write('<tr>\n')
    for activity in sorted_activities:
      out.write('<td>\n')
      first_activity = True
      for log in self.activities[activity]:
        s = ',\n'
        if first_activity:
          s = ''
          first_activity = False
        out.write('%s<a href="#%s">%s</a>' % (s, log.revision, log.revision))
        unique_logs[log] = True
      out.write('</td>\n')
    out.write('</tr>\n')
    out.write('</table>\n\n')
    out.write('</div>\n\n')

    sorted_logs = list(unique_logs.keys())
    sorted_logs.sort()
    for log in sorted_logs:
      out.write('<hr />\n')
      out.write('<div class="h3" id="%s" title="%s">\n' % (log.revision,
                                                           log.revision))
      out.write('<pre>\n')
      if revision_url_pattern:
        revision_url = revision_url_pattern % log.revision[1:]
        revision = '<a href="%s">%s</a>' \
            % (escape_html(revision_url), log.revision)
      else:
        revision = log.revision
      out.write('<b>%s | %s | %s</b>\n\n' % (revision,
                                             escape_html(log.committer),
                                             escape_html(log.date)))
      out.write(spam_guard_in_html_block(escape_html(log.message)))
      out.write('</pre>\n')
      out.write('</div>\n\n')
    out.write('<hr />\n')

    out.write(html_footer())
    out.close()


class Field:
  """One field in one log message."""
  def __init__(self, name, alias = None):
    # The name of this field (e.g., "Patch", "Review", etc).
    self.name = name
    # An alias for the name of this field (e.g., "Reviewed").
    self.alias = alias
    # A list of contributor objects, in the order in which they were
    # encountered in the field.
    self.contributors = [ ]
    # Any parenthesized asides immediately following the field.  The
    # parentheses and trailing newline are left on.  In theory, this
    # supports concatenation of consecutive asides.  In practice, the
    # parser only detects the first one anyway, because additional
    # ones are very uncommon and furthermore by that point one should
    # probably be looking at the full log message.
    self.addendum = ''
  def add_contributor(self, contributor):
    self.contributors.append(contributor)
  def add_endum(self, addendum):
    self.addendum += addendum
  def __str__(self):
    s = 'FIELD: %s (%d contributors)\n' % (self.name, len(self.contributors))
    for contributor in self.contributors:
      s += str(contributor) + '\n'
    s += self.addendum
    return s


class LogMessage:
  # Maps revision strings (e.g., "r12345") onto LogMessage instances,
  # holding all the LogMessage instances ever created.
  all_logs = { }
  # Keep track of youngest rev.
  max_revnum = 0
  def __init__(self, revision, committer, date):
    """Instantiate a log message.  All arguments are strings,
    including REVISION, which should retain its leading 'r'."""
    self.revision = revision
    self.committer = committer
    self.date = date
    self.message = ''
    # Map field names (e.g., "Patch", "Review", "Suggested") onto
    # Field objects.
    self.fields = { }
    if revision in LogMessage.all_logs:
      complain("Revision '%s' seen more than once" % revision, True)
    LogMessage.all_logs[revision] = self
    rev_as_number = int(revision[1:])
    if rev_as_number > LogMessage.max_revnum:
       LogMessage.max_revnum = rev_as_number
  def add_field(self, field):
    self.fields[field.name] = field
  def accum(self, line):
    """Accumulate one more line of raw message."""
    self.message += line

  def __cmp__(self, other):
    """Compare two log messages by revision number, for sort().
    Return -1, 0 or 1 depending on whether a > b, a == b, or a < b.
    Note that this is reversed from normal sorting behavior, but it's
    what we want for reverse chronological ordering of revisions."""
    a = int(self.revision[1:])
    b = int(other.revision[1:])
    if a > b: return -1
    if a < b: return 1
    else:     return 0

  def __hash__(self):
    """I don't really understand why defining __cmp__() but not
    __hash__() renders an object type unfit to be a dictionary key,
    especially in light of the recommendation that if a class defines
    mutable objects and implements __cmp__() or __eq__(), then it
    should not implement __hash__().  See these for details:
    http://mail.python.org/pipermail/python-dev/2004-February/042580.html
    http://mail.python.org/pipermail/python-bugs-list/2003-December/021314.html

    In the meantime, I think it's safe to use the revision as a hash value."""
    return int(self.revision[1:])

  def __str__(self):
    s = '=' * 15
    header = ' LOG: %s | %s ' % (self.revision, self.committer)
    s += header
    s += '=' * 15
    s += '\n'
    for field_name in self.fields.keys():
      s += str(self.fields[field_name]) + '\n'
    s += '-' * 15
    s += '-' * len(header)
    s += '-' * 15
    s += '\n'
    return s



### Code to parse the logs. ##

log_separator = '-' * 72 + '\n'
log_header_re = re.compile\
                ('^(r[0-9]+) \| ([^|]+) \| ([^|]+) \| ([0-9]+)[^0-9]')
field_re = re.compile('^(Patch|Review(ed)?|Suggested|Found) by:\s*(.*)')
field_aliases = { 'Reviewed' : 'Review' }
parenthetical_aside_re = re.compile('^\s*\(.*\)\s*$')

def graze(input):
  just_saw_separator = False

  while True:
    line = input.readline()
    if line == '': break
    if line == log_separator:
      if just_saw_separator:
        sys.stderr.write('Two separators in a row.\n')
        sys.exit(1)
      else:
        just_saw_separator = True
        num_lines = None
        continue
    else:
      if just_saw_separator:
        m = log_header_re.match(line)
        if not m:
          sys.stderr.write('Could not match log message header.\n')
          sys.stderr.write('Line was:\n')
          sys.stderr.write("'%s'\n" % line)
          sys.exit(1)
        else:
          log = LogMessage(m.group(1), m.group(2), m.group(3))
          num_lines = int(m.group(4))
          just_saw_separator = False
          saw_patch = False
          line = input.readline()
          # Handle 'svn log -v' by waiting for the blank line.
          while line != '\n':
            line = input.readline()
          # Parse the log message.
          field = None
          while num_lines > 0:
            line = input.readline()
            log.accum(line)
            m = field_re.match(line)
            if m:
              # We're on the first line of a field.  Parse the field.
              while m:
                if not field:
                  ident = m.group(1)
                  if ident in field_aliases:
                    field = Field(field_aliases[ident], ident)
                  else:
                    field = Field(ident)
                # Each line begins either with "WORD by:", or with whitespace.
                in_field_re = re.compile('^('
                                         + (field.alias or field.name)
                                         + ' by:\s+|\s+)([^\s(].*)')
                m = in_field_re.match(line)
                user, real, email = Contributor.parse(m.group(2))
                if user == 'me':
                  user = log.committer
                c = Contributor.get(user, real, email)
                c.add_activity(field.name, log)
                if (field.name == 'Patch'):
                  saw_patch = True
                field.add_contributor(c)
                line = input.readline()
                if line == log_separator:
                  # If the log message doesn't end with its own
                  # newline (that is, there's the newline added by the
                  # svn client, but no further newline), then just move
                  # on to the next log entry.
                  just_saw_separator = True
                  num_lines = 0
                  break
                log.accum(line)
                num_lines -= 1
                m = in_field_re.match(line)
                if not m:
                  m = field_re.match(line)
                  if not m:
                    aside_match = parenthetical_aside_re.match(line)
                    if aside_match:
                      field.add_endum(line)
                  log.add_field(field)
                  field = None
            num_lines -= 1
          if not saw_patch and log.committer != '(no author)':
            c = Contributor.get(log.committer, None, None)
            c.add_activity('Patch', log)
        continue

index_introduction = '''
<p>The following list of contributors and their contributions is meant
to help us keep track of whom to consider for commit access.  The list
was generated from "svn&nbsp;log" output by <a
href="http://svn.apache.org/repos/asf/subversion/trunk/tools/dev/contribulyze.py"
>contribulyze.py</a>, which looks for log messages that use the <a
href="http://subversion.tigris.org/hacking.html#crediting">special
contribution format</a>.</p>

<p><i>Please do not use this list as a generic guide to who has
contributed what to Subversion!</i> It omits existing <a
href="http://svn.apache.org/repos/asf/subversion/trunk/COMMITTERS"
>full committers</a>, for example, because they are irrelevant to our
search for new committers.  Also, it merely counts changes, it does
not evaluate them.  To truly understand what someone has contributed,
you have to read their changes in detail.  This page can only assist
human judgement, not substitute for it.</p>

'''

def drop(revision_url_pattern):
  # Output the data.
  #
  # The data structures are all linked up nicely to one another.  You
  # can get all the LogMessages, and each LogMessage contains all the
  # Contributors involved with that commit; likewise, each Contributor
  # points back to all the LogMessages it contributed to.
  #
  # However, the HTML output is pretty simple right now.  It's not take
  # full advantage of all that cross-linking.  For each contributor, we
  # just create a file listing all the revisions contributed to; and we
  # build a master index of all contributors, each name being a link to
  # that contributor's individual file.  Much more is possible... but
  # let's just get this up and running first.

  for key in LogMessage.all_logs.keys():
    # You could print out all log messages this way, if you wanted to.
    pass
    # print LogMessage.all_logs[key]

  detail_subdir = "detail"
  if not os.path.exists(detail_subdir):
    os.mkdir(detail_subdir)

  index = open('index.html', 'w')
  index.write(html_header('Contributors as of r%d' % LogMessage.max_revnum))
  index.write(index_introduction)
  index.write('<ol>\n')
  # The same contributor appears under multiple keys, so uniquify.
  seen_contributors = { }
  # Sorting alphabetically is acceptable, but even better would be to
  # sort by number of contributions, so the most active people appear at
  # the top -- that way we know whom to look at first for commit access
  # proposals.
  sorted_contributors = sorted(Contributor.all_contributors.values())
  for c in sorted_contributors:
    if c not in seen_contributors:
      if c.score() > 0:
        if c.is_full_committer:
          # Don't even bother to print out full committers.  They are
          # a distraction from the purposes for which we're here.
          continue
        else:
          committerness = ''
          if c.is_committer:
            committerness = '&nbsp;(partial&nbsp;committer)'
          urlpath = "%s/%s.html" % (detail_subdir, c.canonical_name())
          fname = os.path.join(detail_subdir, "%s.html" % c.canonical_name())
          index.write('<li><p><a href="%s">%s</a>&nbsp;[%s]%s</p></li>\n'
                      % (urllib_parse_quote(urlpath),
                         c.big_name(html=True),
                         c.score_str(), committerness))
          c.html_out(revision_url_pattern, fname)
    seen_contributors[c] = True
  index.write('</ol>\n')
  index.write(html_footer())
  index.close()


def process_committers(committers):
  """Read from open file handle COMMITTERS, which should be in
  the same format as the Subversion 'COMMITTERS' file.  Create
  Contributor objects based on the contents."""
  line = committers.readline()
  while line != 'Blanket commit access:\n':
    line = committers.readline()
  in_full_committers = True
  matcher = re.compile('(\S+)\s+([^\(\)]+)\s+(\([^()]+\)){0,1}')
  line = committers.readline()
  while line:
    # Every @-sign we see after this point indicates a committer line...
    if line == 'Commit access for specific areas:\n':
      in_full_committers = False
    # ...except in the "dormant committers" area, which comes last anyway.
    if line == 'Committers who have asked to be listed as dormant:\n':
      in_full_committers = True
    elif line.find('@') >= 0:
      line = line.lstrip()
      m = matcher.match(line)
      user = m.group(1)
      real_and_email = m.group(2).strip()
      ignored, real, email = Contributor.parse(real_and_email)
      c = Contributor.get(user, real, email)
      c.is_committer = True
      c.is_full_committer = in_full_committers
    line = committers.readline()


def usage():
  print('USAGE: %s [-C COMMITTERS_FILE] < SVN_LOG_OR_LOG-V_OUTPUT' \
        % os.path.basename(sys.argv[0]))
  print('')
  print('Create HTML files in the current directory, rooted at index.html,')
  print('in which you can browse to see who contributed what.')
  print('')
  print('The log input should use the contribution-tracking format defined')
  print('in http://subversion.tigris.org/hacking.html#crediting.')
  print('')
  print('Options:')
  print('')
  print('  -h, -H, -?, --help   Print this usage message and exit')
  print('  -C FILE              Use FILE as the COMMITTERS file')
  print('  -U URL               Use URL as a Python interpolation pattern to')
  print('                       generate URLs to link revisions to some kind')
  print('                       of web-based viewer (e.g. ViewCVS).  The')
  print('                       interpolation pattern should contain exactly')
  print('                       one format specifier, \'%s\', which will be')
  print('                       replaced with the revision number.')
  print('')


def main():
  try:
    opts, args = my_getopt(sys.argv[1:], 'C:U:hH?', [ 'help' ])
  except getopt.GetoptError, e:
    complain(str(e) + '\n\n')
    usage()
    sys.exit(1)

  # Parse options.
  revision_url_pattern = None
  for opt, value in opts:
    if opt in ('--help', '-h', '-H', '-?'):
      usage()
      sys.exit(0)
    elif opt == '-C':
      process_committers(open(value))
    elif opt == '-U':
      revision_url_pattern = value

  # Gather the data.
  graze(sys.stdin)

  # Output the data.
  drop(revision_url_pattern)

if __name__ == '__main__':
  main()
