Added pre-fetching of builds.

tools/bisect-builds.py

 #!/usr/bin/python
 # Copyright (c) 2011 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Snapshot Build Bisect Tool
 
 This script bisects a snapshot archive using binary search. It starts at
 a bad revision (it will try to guess HEAD) and asks for a last known-good
 revision. It will then binary search across this revision range by downloading,
 unzipping, and opening Chromium for you. After testing the specific revision,
 it will ask you whether it is good or bad before continuing the search.
 """
 
 # The root URL for storage.
 BASE_URL = 'http://commondatastorage.googleapis.com/chromium-browser-snapshots'
-BASE_URL_RECENT = 'http://build.chromium.org/f/chromium/snapshots'
 
 # URL to the ViewVC commit page.
 BUILD_VIEWVC_URL = 'http://src.chromium.org/viewvc/chrome?view=rev&revision=%d'
 
 # Changelogs URL.
 CHANGELOG_URL = 'http://build.chromium.org/f/chromium/' \
                 'perf/dashboard/ui/changelog.html?url=/trunk/src&range=%d:%d'
 
 ###############################################################################
 
 import math
 import optparse
 import os
 import pipes
 import re
 import shutil
+import subprocess
 import sys
 import tempfile
+import threading
 import urllib
 from xml.etree import ElementTree
 import zipfile
 
 class PathContext(object):
   """A PathContext is used to carry the information used to construct URLs and
   paths when dealing with the storage server and archives."""
-  def __init__(self, platform, good_revision, bad_revision, use_recent):
+  def __init__(self, platform, good_revision, bad_revision):
     super(PathContext, self).__init__()
     # Store off the input parameters.
     self.platform = platform  # What's passed in to the '-a/--archive' option.
     self.good_revision = good_revision
     self.bad_revision = bad_revision
-    self.use_recent = use_recent
 
     # The name of the ZIP file in a revision directory on the server.
     self.archive_name = None
 
     # Set some internal members:
     #   _listing_platform_dir = Directory that holds revisions. Ends with a '/'.
     #   _archive_extract_dir = Uncompressed directory in the archive_name file.
     #   _binary_name = The name of the executable to run.
     if self.platform == 'linux' or self.platform == 'linux64':
       self._listing_platform_dir = 'Linux/'
       self.archive_name = 'chrome-linux.zip'
       self._archive_extract_dir = 'chrome-linux'
       self._binary_name = 'chrome'
       # Linux and x64 share all the same path data except for the archive dir.
       if self.platform == 'linux64':
         self._listing_platform_dir = 'Linux_x64/'
     elif self.platform == 'mac':
       self._listing_platform_dir = 'Mac/'
       self.archive_name = 'chrome-mac.zip'
       self._archive_extract_dir = 'chrome-mac'
       self._binary_name = 'Chromium.app/Contents/MacOS/Chromium'
     elif self.platform == 'win':
       self._listing_platform_dir = 'Win/'
       self.archive_name = 'chrome-win32.zip'
       self._archive_extract_dir = 'chrome-win32'
       self._binary_name = 'chrome.exe'
     else:
-      raise Exception("Invalid platform")
+      raise Exception('Invalid platform: %s' % self.platform)
 
   def GetListingURL(self, marker=None):
     """Returns the URL for a directory listing, with an optional marker."""
     marker_param = ''
     if marker:
       marker_param = '&marker=' + str(marker)
     return BASE_URL + '/?delimiter=/&prefix=' + self._listing_platform_dir + \
         marker_param
 
-  def GetListingURLRecent(self):
-    """Returns the URL for a directory listing of recent builds."""
-    return BASE_URL_RECENT + '/' + self._listing_platform_dir
-
   def GetDownloadURL(self, revision):
     """Gets the download URL for a build archive of a specific revision."""
-    if self.use_recent:
-      return "%s/%s%d/%s" % (
-          BASE_URL_RECENT, self._listing_platform_dir, revision,
-          self.archive_name)
-    else:
-      return "%s/%s%d/%s" % (
-          BASE_URL, self._listing_platform_dir, revision, self.archive_name)
+    return "%s/%s%d/%s" % (
+        BASE_URL, self._listing_platform_dir, revision, self.archive_name)
 
   def GetLastChangeURL(self):
     """Returns a URL to the LAST_CHANGE file."""
     return BASE_URL + '/' + self._listing_platform_dir + 'LAST_CHANGE'
 
   def GetLaunchPath(self):
     """Returns a relative path (presumably from the archive extraction location)
     that is used to run the executable."""
     return os.path.join(self._archive_extract_dir, self._binary_name)
 
+  def ParseDirectoryIndex(self):
+    """Parses the Google Storage directory listing into a list of revision
+    numbers. The range starts with self.good_revision and goes until
+    self.bad_revision."""
+
+    def _FetchAndParse(url):
+      """Fetches a URL and returns a 2-Tuple of ([revisions], next-marker). If
+      next-marker is not None, then the listing is a partial listing and another
+      fetch should be performed with next-marker being the marker= GET
+      parameter."""
+      handle = urllib.urlopen(url)
+      document = ElementTree.parse(handle)
+
+      # All nodes in the tree are namespaced. Get the root's tag name to extract
+      # the namespace. Etree does namespaces as |{namespace}tag|.
+      root_tag = document.getroot().tag
+      end_ns_pos = root_tag.find('}')
+      if end_ns_pos == -1:
+        raise Exception("Could not locate end namespace for directory index")
+      namespace = root_tag[:end_ns_pos + 1]
+
+      # Find the prefix (_listing_platform_dir) and whether or not the list is
+      # truncated.
+      prefix_len = len(document.find(namespace + 'Prefix').text)
+      next_marker = None
+      is_truncated = document.find(namespace + 'IsTruncated')
+      if is_truncated is not None and is_truncated.text.lower() == 'true':
+        next_marker = document.find(namespace + 'NextMarker').text
+
+      # Get a list of all the revisions.
+      all_prefixes = document.findall(namespace + 'CommonPrefixes/' +
+                                      namespace + 'Prefix')
+      # The <Prefix> nodes have content of the form of
+      # |_listing_platform_dir/revision/|. Strip off the platform dir and the
+      # trailing slash to just have a number.
+      revisions = []
+      for prefix in all_prefixes:
+        revnum = prefix.text[prefix_len:-1]
+        try:
+          revnum = int(revnum)
+          revisions.append(revnum)
+        except ValueError:
+          pass
+      return (revisions, next_marker)
+
+    # Fetch the first list of revisions.
+    (revisions, next_marker) = _FetchAndParse(self.GetListingURL())
+
+    # If the result list was truncated, refetch with the next marker. Do this
+    # until an entire directory listing is done.
+    while next_marker:
+      next_url = self.GetListingURL(next_marker)
+      (new_revisions, next_marker) = _FetchAndParse(next_url)
+      revisions.extend(new_revisions)
+
+    return revisions
+
+  def GetRevList(self):
+    """Gets the list of revision numbers between self.good_revision and
+    self.bad_revision."""
+    # Download the revlist and filter for just the range between good and bad.
+    minrev = self.good_revision
+    maxrev = self.bad_revision
+    revlist = map(int, self.ParseDirectoryIndex())
+    revlist = [x for x in revlist if x >= minrev and x <= maxrev]
+    revlist.sort()
+    return revlist
+
 
 def UnzipFilenameToDir(filename, dir):
   """Unzip |filename| to directory |dir|."""
+  cwd = os.getcwd()
+  if not os.path.isabs(filename):
+    filename = os.path.join(cwd, filename)
   zf = zipfile.ZipFile(filename)
   # Make base.
-  pushd = os.getcwd()
   try:
     if not os.path.isdir(dir):
       os.mkdir(dir)
     os.chdir(dir)
     # Extract files.
     for info in zf.infolist():
       name = info.filename
       if name.endswith('/'):  # dir
         if not os.path.isdir(name):
           os.makedirs(name)
       else:  # file
         dir = os.path.dirname(name)
         if not os.path.isdir(dir):
           os.makedirs(dir)
         out = open(name, 'wb')
         out.write(zf.read(name))
         out.close()
       # Set permissions. Permission info in external_attr is shifted 16 bits.
       os.chmod(name, info.external_attr >> 16L)
-    os.chdir(pushd)
+    os.chdir(cwd)
   except Exception, e:
     print >>sys.stderr, e
     sys.exit(1)
 
 
-def ParseDirectoryIndex(context):
-  """Parses the Google Storage directory listing into a list of revision
-  numbers. The range starts with context.good_revision and goes until the latest
-  revision."""
-  def _FetchAndParse(url):
-    """Fetches a URL and returns a 2-Tuple of ([revisions], next-marker). If
-    next-marker is not None, then the listing is a partial listing and another
-    fetch should be performed with next-marker being the marker= GET
-    parameter."""
-    handle = urllib.urlopen(url)
-    document = ElementTree.parse(handle)
+def FetchRevision(context, rev, filename, quit_event=None):
+  """Downloads and unzips revision |rev|.
+  @param context A PathContext instance.
+  @param rev The chromium revision number/tag to download.

[Robert Sesek, 2011/07/26 21:00:26]

nit: capitalization

[szager1, 2011/07/29 17:19:21]

Done.

+  @param filename The destination for the downloaded file.
+  @param quit_event A threading.Event which will be set by the master thread to
+                    indicate that the download should be aborted.
+  """
+  def ReportHook(blocknum, blocksize, totalsize):
+    if quit_event and quit_event.is_set():
+     raise RuntimeError("Aborting download of revision %d" % rev)
 
-    # All nodes in the tree are namespaced. Get the root's tag name to extract
-    # the namespace. Etree does namespaces as |{namespace}tag|.
-    root_tag = document.getroot().tag
-    end_ns_pos = root_tag.find('}')
-    if end_ns_pos == -1:
-      raise Exception("Could not locate end namespace for directory index")
-    namespace = root_tag[:end_ns_pos + 1]
-
-    # Find the prefix (_listing_platform_dir) and whether or not the list is
-    # truncated.
-    prefix_len = len(document.find(namespace + 'Prefix').text)
-    next_marker = None
-    is_truncated = document.find(namespace + 'IsTruncated')
-    if is_truncated is not None and is_truncated.text.lower() == 'true':
-      next_marker = document.find(namespace + 'NextMarker').text
-
-    # Get a list of all the revisions.
-    all_prefixes = document.findall(namespace + 'CommonPrefixes/' +
-                                    namespace + 'Prefix')
-    # The <Prefix> nodes have content of the form of
-    # |_listing_platform_dir/revision/|. Strip off the platform dir and the
-    # trailing slash to just have a number.
-    revisions = []
-    for prefix in all_prefixes:
-      revnum = prefix.text[prefix_len:-1]
-      try:
-        revnum = int(revnum)
-        revisions.append(revnum)
-      except ValueError:
-        pass
-    return (revisions, next_marker)
-
-  # Fetch the first list of revisions.
-  (revisions, next_marker) = _FetchAndParse(context.GetListingURL())
-  # If the result list was truncated, refetch with the next marker. Do this
-  # until an entire directory listing is done.
-  while next_marker:
-    (new_revisions, next_marker) = _FetchAndParse(
-        context.GetListingURL(next_marker))
-    revisions.extend(new_revisions)
-
-  return revisions
+  download_url = context.GetDownloadURL(rev)
+  try:
+    urllib.urlretrieve(download_url, filename, ReportHook)
+  except RuntimeError, e:
+    pass
 
 
-def ParseDirectoryIndexRecent(context):
-  """Parses the recent builds directory listing into a list of revision
-  numbers."""
-  handle = urllib.urlopen(context.GetListingURLRecent())
-  document = handle.read()
+def RunRevision(context, revision, zipfile, profile, args):
+  """Given a zipped revision, unzip it and run the test."""
+  print "Trying revision %d..." % revision
 
-  # Looking for: <a href="92976/">92976/</a>
-  return re.findall(r"<a href=\"(\d+)/\">\1/</a>", document)
-
-
-def FilterRevList(context, revlist):
-  """Filter revlist to the revisions between |good_revision| and
-  |bad_revision| of the |context|."""
-  # Download the revlist and filter for just the range between good and bad.
-  rev_range = range(context.good_revision, context.bad_revision)
-  revlist = filter(lambda r: r in rev_range, revlist)
-  revlist.sort()
-  return revlist
-
-
-def TryRevision(context, rev, profile, args):
-  """Downloads revision |rev|, unzips it, and opens it for the user to test.
-  |profile| is the profile to use."""
-  # Do this in a temp dir so we don't collide with user files.
+  # Create a temp directory and unzip the revision into it
   cwd = os.getcwd()
   tempdir = tempfile.mkdtemp(prefix='bisect_tmp')
+  UnzipFilenameToDir(zipfile, tempdir)
   os.chdir(tempdir)
 
-  # Download the file.
-  download_url = context.GetDownloadURL(rev)
-  def _ReportHook(blocknum, blocksize, totalsize):
-    size = blocknum * blocksize
-    if totalsize == -1:  # Total size not known.
-      progress = "Received %d bytes" % size
-    else:
-      size = min(totalsize, size)
-      progress = "Received %d of %d bytes, %.2f%%" % (
-          size, totalsize, 100.0 * size / totalsize)
-    # Send a \r to let all progress messages use just one line of output.
-    sys.stdout.write("\r" + progress)
-    sys.stdout.flush()
-  try:
-    print 'Fetching ' + download_url
-    urllib.urlretrieve(download_url, context.archive_name, _ReportHook)
-    print
-    # Throw an exception if the download was less than 1000 bytes.
-    if os.path.getsize(context.archive_name) < 1000: raise Exception()
-  except Exception, e:
-    print('Could not retrieve the download. Sorry.')
-    sys.exit(-1)
-
-  # Unzip the file.
-  print 'Unzipping ...'
-  UnzipFilenameToDir(context.archive_name, os.curdir)
-
-  # Tell the system to open the app.
-  args = ['--user-data-dir=%s' % profile] + args
-  flags = ' '.join(map(pipes.quote, args))
-  cmd = '%s %s' % (context.GetLaunchPath(), flags)
-  print 'Running %s' % cmd
-  os.system(cmd)
+  # Run the test
+  testargs = [context.GetLaunchPath(), '--user-data-dir=%s' % profile] + args
+  subproc = subprocess.Popen(testargs,
+                             bufsize=-1,
+                             stdout=subprocess.PIPE,
+                             stderr=subprocess.PIPE)
+  (stdout, stderr) = subproc.communicate()
 
   os.chdir(cwd)
-  print 'Cleaning temp dir ...'
   try:
     shutil.rmtree(tempdir, True)
   except Exception, e:
     pass
 
+  return (subproc.returncode, stdout, stderr)
 
-def AskIsGoodBuild(rev):
+def AskIsGoodBuild(rev, status, stdout, stderr):
   """Ask the user whether build |rev| is good or bad."""
   # Loop until we get a response that we can parse.
   while True:
-    response = raw_input('\nBuild %d is [(g)ood/(b)ad]: ' % int(rev))
+    response = raw_input('\nRevision %d is [(g)ood/(b)ad/(q)uit]: ' % int(rev))
     if response and response in ('g', 'b'):
       return response == 'g'
+    if response and response == 'q':
+      raise SystemExit()
 
+def Bisect(platform,
+           good_rev=0,
+           bad_rev=0,
+           try_args=(),
+           profile=None,
+           predicate=AskIsGoodBuild):
+  """Given known good and known bad revisions, run a binary search on all
+  archived revisions to determine the last known good revision.
 
-def Bisect(revlist,
-           context,
-           try_args=(),
-           profile='profile',
-           predicate=AskIsGoodBuild):
-  """Tries to find the exact commit where a regression was introduced by
-  running a binary search on all archived builds in a given revision range.
-
-  @param revlist A list of chromium revision numbers to check.
-  @param context A PathContext object.
-  @param try_args A tuple of arguments to pass to the predicate function.
-  @param profile The user profile with which to run chromium.
+  @param platform Which build to download/run ('mac', 'win', 'linux64', etc.).
+  @param good_rev Number/tag of the last known good revision.
+  @param bad_rev Number/tag of the first known bad revision.
+  @param try_args A tuple of arguments to pass to the test application.
+  @param profile The name of the user profile to run with.
   @param predicate A predicate function which returns True iff the argument
                    chromium revision is good.
+
+  Threading is used to fetch chromium revisions in the background, speeding up

[Robert Sesek, 2011/07/26 21:00:26]

nit: capitalization

[szager1, 2011/07/29 17:19:21]

Done.

+  the user's experience.  For example, suppose the bounds of the search are

[Robert Sesek, 2011/07/26 21:00:26]

über-nit: this file uses single spaces between sentences. You should also avoid
the use of the first person in comments.

[szager1, 2011/07/29 17:19:21]

Done.

+  good_rev=0, bad_rev=100.  The first revision we'd like to check is 50.
+  Depending on whether revision 50 is good or bad, the next revision to check
+  will be either 25 or 75.  So, while revision 50 is being checked, we download
+  revisions 25 and 75 in the background.  Once we know the good/bad verdict on
+  rev 50:
+
+    - If rev 50 is good, we cancel the download of rev 25, and run the next test
+      on rev 75.
+
+    - If rev 50 is bad, we cancel the download of rev 75, and run the next test
+      on rev 25.
   """
 
+  if not profile:
+    profile = 'profile'
+
+  context = PathContext(platform, good_rev, bad_rev)
+  cwd = os.getcwd()
+
+  GetDownloadPath = lambda rev: os.path.join(cwd, '%d-%s' % (

[Robert Sesek, 2011/07/26 21:00:26]

Can you break this after the comma? That's probably a little cleaner looking.
Prefix with _ to make it clear it's local?

[szager1, 2011/07/29 17:19:21]

Done.

+      rev, context.archive_name))
+
+  revlist = context.GetRevList()
+
+  # Get a list of revisions to bisect across.
+  if len(revlist) < 2:  # Don't have enough builds to bisect
+    msg = 'We don\'t have enough builds to bisect. revlist: %s' % revlist
+    raise RuntimeError(msg)
+
+  # Figure out our bookends and first pivot point; fetch the pivot revision
   good = 0
   bad = len(revlist) - 1
-  last_known_good_rev = revlist[good]
-  first_known_bad_rev = revlist[bad]
+  pivot = bad / 2
+  rev = revlist[pivot]
+  zipfile = GetDownloadPath(rev)
+  print "Downloading revision %d..." % rev
+  FetchRevision(context, rev, zipfile)
 
   # Binary search time!
-  while good < bad:
-    candidates = revlist[good:bad]
-    num_poss = len(candidates)
-    if num_poss > 10:
-      print('%d candidates. %d tries left.' %
-          (num_poss, round(math.log(num_poss, 2))))
-    else:
-      print('Candidates: %s' % revlist[good:bad])
+  while zipfile and bad - good > 1:
+    # Pre-fetch next two possible pivots
+    #   - down_pivot is the next revision to check if the current revision turns
+    #     out to be bad.
+    #   - up_pivot is the next revision to check if the current revision turns
+    #     out to be good.
+    down_pivot = int((pivot - good) / 2) + good
+    down_thread = None
+    if down_pivot != pivot and down_pivot != good:
+      down_rev = revlist[down_pivot]
+      down_zipfile = GetDownloadPath(down_rev)
+      down_event = threading.Event()
+      fetchargs = (context, down_rev, down_zipfile, down_event)
+      down_thread = threading.Thread(target=FetchRevision,
+                                     name='down_fetch',
+                                     args=fetchargs)
+      down_thread.start()
 
-    # Cut the problem in half...
-    test = int((bad - good) / 2) + good
-    test_rev = revlist[test]
+    up_pivot = int((bad - pivot) / 2) + pivot
+    up_thread = None
+    if up_pivot != pivot and up_pivot != bad:
+      up_rev = revlist[up_pivot]
+      up_zipfile = GetDownloadPath(up_rev)
+      up_event = threading.Event()
+      fetchargs = (context, up_rev, up_zipfile, up_event)
+      up_thread = threading.Thread(target=FetchRevision,
+                                   name='up_fetch',
+                                   args=fetchargs)
+      up_thread.start()
 
-    # Let the user give this rev a spin (in her own profile, if she wants).
-    TryRevision(context, test_rev, profile, try_args)
-    if predicate(test_rev):
-      last_known_good_rev = test_rev
-      good = test + 1
-    else:
-      bad = test
+    # Run test on the pivot revision

[Robert Sesek, 2011/07/26 21:00:26]

nit: full-stop comments. Here and elsewhere.

[szager1, 2011/07/29 17:19:21]

Done.

+    (status, stdout, stderr) = RunRevision(context,
+                                           rev,
+                                           zipfile,
+                                           profile,
+                                           try_args)
+    os.unlink(zipfile)
+    zipfile = None
+    try:

[Robert Sesek, 2011/07/26 21:00:26]

This block needs a comment.

[szager1, 2011/07/29 17:19:21]

Done.

+      if predicate(rev, status, stdout, stderr):

[Robert Sesek, 2011/07/26 21:00:26]

Could the work in these two branches be refactored out into a function?

[szager1, 2011/07/29 17:19:21]

Perhaps, but it would have to be one of those functions with lots of arguments
and just a few lines of code.  If I *really* wanted to abstract out this code, I
would probably create a new class which encapsulates down_thread, down_event,
down_pivot, etc.  Could go either way, but I tend to think that would be
overkill.

+        good = pivot
+        if down_thread:
+          down_event.set()  # Kill the download of older revision
+          down_thread.join()

[Robert Sesek, 2011/07/26 21:00:26]

Would it make sense to reuse the threads so you don't have to create and join
them? Or do you think that is more work than it's worth?

[szager1, 2011/07/29 17:19:21]

I don't think there's any measurable performance gain to be had there.

+          os.unlink(down_zipfile)
+        if up_thread:
+          print "Downloading revision %d..." % up_rev
+          up_thread.join()  # Wait for newer revision to finish downloading
+          pivot = up_pivot
+          zipfile = up_zipfile
+      else:
+        bad = pivot
+        if up_thread:
+          up_event.set()  # Kill download of newer revision
+          up_thread.join()
+          os.unlink(up_zipfile)
+        if down_thread:
+          print "Downloading revision %d..." % down_rev
+          down_thread.join()  # Wait for older revision to finish downloading
+          pivot = down_pivot
+          zipfile = down_zipfile
+    except SystemExit:
+      for f in [down_zipfile, up_zipfile]:
+        try:
+          os.unlink(f)
+        except OSError:
+          pass
+      sys.exit(0)
 
-  return (last_known_good_rev, first_known_bad_rev)
+    rev = revlist[pivot]
+
+  return (revlist[good], revlist[bad])
 
 
 def main():
   usage = ('%prog [options] [-- chromium-options]\n'
            'Perform binary search on the snapshot builds.\n'
            '\n'
            'Tip: add "-- --no-first-run" to bypass the first run prompts.')
   parser = optparse.OptionParser(usage=usage)
   # Strangely, the default help output doesn't include the choice list.
   choices = ['mac', 'win', 'linux', 'linux64']
@@ skipping 17 matching lines @@
     parser.print_help()
     return 1
 
   if opts.bad and opts.good and (opts.good > opts.bad):
     print ('The good revision (%d) must precede the bad revision (%d).\n' %
            (opts.good, opts.bad))
     parser.print_help()
     return 1
 
   # Create the context. Initialize 0 for the revisions as they are set below.
-  context = PathContext(opts.archive, 0, 0, use_recent=False)
+  context = PathContext(opts.archive, 0, 0)
 
   # Pick a starting point, try to get HEAD for this.
   if opts.bad:
     bad_rev = opts.bad
   else:
     bad_rev = 0
     try:
       # Location of the latest build revision number
       nh = urllib.urlopen(context.GetLastChangeURL())
       latest = int(nh.read())
       nh.close()
       bad_rev = raw_input('Bad revision [HEAD:%d]: ' % latest)
       if (bad_rev == ''):
         bad_rev = latest
       bad_rev = int(bad_rev)
     except Exception, e:
       print('Could not determine latest revision. This could be bad...')
       bad_rev = int(raw_input('Bad revision: '))
 
   # Find out when we were good.
   if opts.good:
     good_rev = opts.good
   else:
     good_rev = 0
     try:
       good_rev = int(raw_input('Last known good [0]: '))
     except Exception, e:
       pass
 
-  # Set the input parameters now that they've been validated.
-  context.good_revision = good_rev
-  context.bad_revision = bad_rev
-
-  # Get recent revision list and check whether it's sufficient.
-  all_revs_recent = map(int, ParseDirectoryIndexRecent(context))
-  all_revs_recent.sort()
-  # Skipping 0 since it might be deleted off the server soon:
-  all_revs_recent = all_revs_recent[1:]
-  oldest_recent_rev = all_revs_recent[0]
-  if good_rev >= oldest_recent_rev:
-    # The range is within recent builds, so switch on use_recent.
-    context.use_recent = True
-  elif bad_rev >= oldest_recent_rev:
-    # The range spans both old and recent builds.
-    # If oldest_recent_rev is good, we bisect the recent builds.
-    context.use_recent = True
-    TryRevision(context, oldest_recent_rev, opts.profile, args)
-    if AskIsGoodBuild(oldest_recent_rev):
-      # context.use_recent is True
-      context.good_revision = oldest_recent_rev
-    else:
-      context.use_recent = False
-      context.bad_revision = oldest_recent_rev
-
-  all_revs = []
-  if context.use_recent:
-    all_revs = all_revs_recent
-  else:
-    all_revs = map(int, ParseDirectoryIndex(context))
-
-  # Filter list of revisions to bisect across.
-  revlist = FilterRevList(context, all_revs)
-  if len(revlist) < 2:  # Don't have enough builds to bisect
-    print 'We don\'t have enough builds to bisect. revlist: %s' % revlist
-    sys.exit(1)
-
   (last_known_good_rev, first_known_bad_rev) = Bisect(
-      revlist, context, args, opts.profile)
+      opts.archive, good_rev, bad_rev, args, opts.profile)
 
   # We're done. Let the user know the results in an official manner.
   print('You are probably looking for build %d.' % first_known_bad_rev)
   print('CHANGELOG URL:')
   print(CHANGELOG_URL % (last_known_good_rev, first_known_bad_rev))
   print('Built at revision:')
   print(BUILD_VIEWVC_URL % first_known_bad_rev)
 
 if __name__ == '__main__':
   sys.exit(main())