--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mercurial/bookmarks.py	Thu Feb 10 13:46:27 2011 -0600
@@ -0,0 +1,73 @@
+# Mercurial bookmark support code
+#
+# Copyright 2008 David Soria Parra <dsp@php.net>
+#
+# This software may be used and distributed according to the terms of the
+# GNU General Public License version 2 or any later version.
+
+from mercurial.i18n import _
+from mercurial.node import nullid, nullrev, bin, hex, short
+from mercurial import encoding
+import os
+
+def write(repo):
+    '''Write bookmarks
+
+    Write the given bookmark => hash dictionary to the .hg/bookmarks file
+    in a format equal to those of localtags.
+
+    We also store a backup of the previous state in undo.bookmarks that
+    can be copied back on rollback.
+    '''
+    refs = repo._bookmarks
+
+    try:
+        bms = repo.opener('bookmarks').read()
+    except IOError:
+        bms = ''
+    repo.opener('undo.bookmarks', 'w').write(bms)
+
+    if repo._bookmarkcurrent not in refs:
+        setcurrent(repo, None)
+    wlock = repo.wlock()
+    try:
+        file = repo.opener('bookmarks', 'w', atomictemp=True)
+        for refspec, node in refs.iteritems():
+            file.write("%s %s\n" % (hex(node), encoding.fromlocal(refspec)))
+        file.rename()
+
+        # touch 00changelog.i so hgweb reloads bookmarks (no lock needed)
+        try:
+            os.utime(repo.sjoin('00changelog.i'), None)
+        except OSError:
+            pass
+
+    finally:
+        wlock.release()
+
+def setcurrent(repo, mark):
+    '''Set the name of the bookmark that we are currently on
+
+    Set the name of the bookmark that we are on (hg update <bookmark>).
+    The name is recorded in .hg/bookmarks.current
+    '''
+    current = repo._bookmarkcurrent
+    if current == mark:
+        return
+
+    refs = repo._bookmarks
+
+    # do not update if we do update to a rev equal to the current bookmark
+    if (mark and mark not in refs and
+        current and refs[current] == repo.changectx('.').node()):
+        return
+    if mark not in refs:
+        mark = ''
+    wlock = repo.wlock()
+    try:
+        file = repo.opener('bookmarks.current', 'w', atomictemp=True)
+        file.write(mark)
+        file.rename()
+    finally:
+        wlock.release()
+    repo._bookmarkcurrent = mark