bookmarks: add appropriate locking (issue1691)

- make updates of bookmark state locked and atomic
- wrap commit so that commit and bookmarks happen under the same lock

hgext/bookmarks.py

@@ -64,10 +64,14 b' def write(repo, refs):'
         util.copyfile(repo.join('bookmarks'), repo.join('undo.bookmarks'))
     if current(repo) not in refs:
         setcurrent(repo, None)
-    file = repo.opener('bookmarks', 'w+')
+    wlock = repo.wlock()
+    try:
+        file = repo.opener('bookmarks', 'w', atomictemp=True)
     for refspec, node in refs.iteritems():
         file.write("%s %s\n" % (hex(node), refspec))
-    file.close()
+        file.rename()
+    finally:
+        wlock.release()
 
 def current(repo):
     '''Get the current bookmark
@@ -106,9 +110,13 b' def setcurrent(repo, mark):'
         return
     if mark not in refs:
         mark = ''
-    file = repo.opener('bookmarks.current', 'w+')
+    wlock = repo.wlock()
+    try:
+        file = repo.opener('bookmarks.current', 'w', atomictemp=True)
     file.write(mark)
-    file.close()
+        file.rename()
+    finally:
+        wlock.release()
     repo._bookmarkcurrent = mark
 
 def bookmark(ui, repo, mark=None, rev=None, force=False, delete=False, rename=None):
@@ -242,6 +250,8 b' def reposetup(ui, repo):'
         def commit(self, *k, **kw):
             """Add a revision to the repository and
             move the bookmark"""
+            wlock = self.wlock() # do both commit and bookmark with lock held
+            try:
             node  = super(bookmark_repo, self).commit(*k, **kw)
             if node is None:
                 return None
@@ -262,6 +272,8 b' def reposetup(ui, repo):'
             if update:
                 write(repo, marks)
             return node
+            finally:
+                wlock.release()
 
         def addchangegroup(self, source, srctype, url, emptyok=False):
             parents = repo.dirstate.parents()