--- a/hgsubversion/util.py
+++ b/hgsubversion/util.py
@@ -1,10 +1,65 @@
+import re
 import os
+import urllib
 
 from mercurial import hg
 from mercurial import node
 from mercurial import util as hgutil
 
 
+b_re = re.compile(r'^\+\+\+ b\/([^\n]*)', re.MULTILINE)
+a_re = re.compile(r'^--- a\/([^\n]*)', re.MULTILINE)
+devnull_re = re.compile(r'^([-+]{3}) /dev/null', re.MULTILINE)
+header_re = re.compile(r'^diff --git .* b\/(.*)', re.MULTILINE)
+newfile_devnull_re = re.compile(r'^--- /dev/null\n\+\+\+ b/([^\n]*)',
+                                re.MULTILINE)
+
+
+def formatrev(rev):
+    if rev == -1:
+        return '\t(working copy)'
+    return '\t(revision %d)' % rev
+
+
+def filterdiff(diff, oldrev, newrev):
+    diff = newfile_devnull_re.sub(r'--- \1\t(revision 0)' '\n'
+                                  r'+++ \1\t(working copy)',
+                                  diff)
+    oldrev = formatrev(oldrev)
+    newrev = formatrev(newrev)
+    diff = a_re.sub(r'--- \1'+ oldrev, diff)
+    diff = b_re.sub(r'+++ \1' + newrev, diff)
+    diff = devnull_re.sub(r'\1 /dev/null\t(working copy)', diff)
+    diff = header_re.sub(r'Index: \1' + '\n' + ('=' * 67), diff)
+    return diff
+
+
+def parentrev(ui, repo, meta, hashes):
+    """Find the svn parent revision of the repo's dirstate.
+    """
+    workingctx = repo.parents()[0]
+    outrev = outgoing_revisions(repo, hashes, workingctx.node())
+    if outrev:
+        workingctx = repo[outrev[-1]].parents()[0]
+    return workingctx
+
+
+def islocalrepo(url):
+    if not url.startswith('file:///'):
+        return False
+    if '#' in url.split('/')[-1]: # strip off #anchor
+        url = url[:url.rfind('#')]
+    path = url[len('file://'):]
+    path = urllib.url2pathname(path).replace(os.sep, '/')
+    while '/' in path:
+        if reduce(lambda x,y: x and y,
+                  map(lambda p: os.path.exists(os.path.join(path, p)),
+                      ('hooks', 'format', 'db', ))):
+            return True
+        path = path.rsplit('/', 1)[0]
+    return False
+
+
 def getuserpass(opts):
     # DO NOT default the user to hg's getuser(). If you provide
     # *any* default username to Subversion, it won't use any remembered