Part 2 of 3: Moving tools/llvm to pnacl/

tools/llvm/diff-diff.py

-#!/usr/bin/python
-# Copyright 2011 The Native Client Authors.  All rights reserved.
-# Use of this source code is governed by a BSD-style license that can
-# be found in the LICENSE file.
-
-import sys
-import subprocess
-import os
-import tempfile
-
-def main():
-  if len(sys.argv) not in (2,3):
-    print "Syntax: %s <repo_dir> [merge_rev]" % (sys.argv[0])
-    print "If merge_rev is omitted, this script produces a"
-    print "diff-diff of the merge in the working directory."
-    sys.exit(0)
-
-  repo_dir = sys.argv[1]
-  merge_rev = None
-  if len(sys.argv) == 3:
-    merge_rev = sys.argv[2]
-
-  diffdiff(repo_dir, merge_rev)
-  return 0
-
-def diffdiff(repo_dir, merge_rev = None):
-  """ Print the 'diff diff' of a merge.
-
-      This is roughly equivalent to doing:
-        hg diff vendor:pnacl-sfi > tmp1  (before the merge)
-        hg diff vendor:pnacl-sfi > tmp2  (after the merge)
-        diff tmp1 tmp2                   (this is the diff-diff)
-
-      If merge_rev is None, prints the diff-diff of the
-      current merge in progress (in the working directory).
-      If merge_rev is specified, the diff-diff of an previous
-      (already committed) merge is generated."""
-
-  entries = GetMercurialLog(repo_dir)
-
-  if merge_rev:
-    if merge_rev not in entries:
-      Fatal("Can't find revision '%s'" % merge_rev)
-    cur = entries[merge_rev]
-    if len(cur['parent']) != 2:
-      Fatal("Specified revision is not a merge!")
-    p1,p2 = cur['parent']
-  else:
-    cur = None
-    p1,p2 = GetWorkingDirParents(entries, repo_dir)
-
-  # Make p1 the "vendor" branch parent
-  if p2['branch'] == 'vendor':
-    p1,p2 = p2,p1
-
-  # Identify and verify the situation
-  if cur:
-    assert(cur['branch'] == 'pnacl-sfi')
-  assert(p1['branch'] == 'vendor')
-  assert(p2['branch'] == 'pnacl-sfi')
-  assert(len(p1['parent']) == 1)
-  prev_vendor = p1['parent'][0]
-  prev_merge = FindPreviousMerge(p2)
-  assert(prev_vendor['branch'] == 'vendor')
-  assert(prev_merge['branch'] == 'pnacl-sfi')
-  assert(prev_vendor in prev_merge['parent'])
-
-  diff1 = MakeTemp(hg_diff(repo_dir, prev_vendor, p2))
-  diff2 = MakeTemp(hg_diff(repo_dir, p1, cur))
-
-  out,err,ret = Run(None, ['diff',diff1,diff2], errexit=False)
-  if ret == 2:
-    Fatal("diff failed (%d): %s" % (ret, err))
-  if ret == 0:
-    Fatal("diff output empty")
-  if ret != 1:
-    Fatal("Unexpected return value from diff (%d)" % ret)
-  sys.stdout.write(out)
-
-  DeleteTemp(diff1)
-  DeleteTemp(diff2)
-  return 0
-
-def hg_diff(dir, r1, r2):
-  assert(r1 is not None)
-  if r2 is None:
-    return Run(dir, "hg diff -r %s" % r1['changeset'])
-  else:
-    return Run(dir, "hg diff -r %s:%s" % (r1['changeset'], r2['changeset']))
-
-def MakeTemp(contents):
-  """ Create a temporary file with specific contents,
-      and return the filename """
-
-  f,tempname = tempfile.mkstemp(prefix='diff-diff-tmp')
-  f = open(tempname, 'w')
-  f.write(contents)
-  f.close()
-  return tempname
-
-def DeleteTemp(tempname):
-  os.remove(tempname)
-
-def Fatal(msg):
-  print msg
-  sys.exit(1)
-
-def Run(dir, args, errexit=True):
-  if isinstance(args, str):
-    args = args.split(' ')
-  p = subprocess.Popen(args, cwd=dir,
-                       stdout=subprocess.PIPE,
-                       stderr=subprocess.PIPE)
-  out, err = p.communicate()
-  if not errexit:
-    return out, err, p.returncode
-  if p.returncode:
-    Fatal("%s (%d): (STDERR): %s" % (' '.join(args), p.returncode, err))
-  if len(err) > 0:
-    Fatal("%s (STDERR): %s" % (' '.join(args), err))
-  return out
-
-
-def GetWorkingDirParents(entries, dir):
-  out = Run(dir, 'hg identify -i')
-  revs = out.split('+')
-
-  # If this is a merge, hg identify -i returns:
-  #   changeset1+changeset2+
-  if len(revs) != 3:
-    Fatal("Working directory is not a merge. Please specify a revision!")
-  return entries[revs[0]], entries[revs[1]]
-
-def GetMercurialLog(dir):
-  """ Read the Mercurial log into a dictionary of log entries """
-  entries = []
-  out = Run(dir, 'hg log')
-  blocks = out.strip().split('\n\n')
-  for b in blocks:
-    entry = dict()
-    entry['parent'] = []
-    for line in b.split('\n'):
-      sep = line.find(':')
-      tag = line[0:sep]
-      val = line[sep+1:].strip()
-      if tag == 'parent':
-        entry[tag] = entry[tag] + [ val ]
-      else:
-        entry[tag] = val
-    entries.append(entry)
-
-  # Remove revision ids
-  for entry in entries:
-    entry['changeset'] = entry['changeset'].split(':')[1]
-    entry['parent'] = [ s.split(':')[1] for s in entry['parent'] ]
-
-  # Add missing parent info for consecutive entries
-  last_entry = []
-  for entry in reversed(entries):
-    if len(entry['parent']) == 0:
-      entry['parent'] = last_entry
-    last_entry = [ entry['changeset'] ]
-
-  # Convert to a dictionary indexed by changeset
-  entries = dict([(entry['changeset'], entry) for entry in entries])
-
-  # Convert the parents to direct entry references
-  for cs, entry in entries.iteritems():
-    entry['parent'] = [ entries[r] for r in entry['parent'] ]
-
-  return entries
-
-def FindPreviousMerge(entry):
-  p = entry
-  while len(p['parent']) == 1:
-    p = p['parent'][0]
-  if len(p['parent']) != 2:
-    Fatal("Couldn't find previous merge for %s!" % entry['changeset'])
-  return p
-
-if __name__ == '__main__':
-  sys.exit(main())