--- /dev/null
+from mercurial import context
+from mercurial.i18n import _
+
+'''
+[extensions]
+hgfilesize=~/m5/incoming/util/hgfilesize.py
+
+[hooks]
+pretxncommit = python:hgfilesize.limit_file_size
+pretxnchangegroup = python:hgfilesize.limit_file_size
+
+[limit_file_size]
+maximum_file_size = 200000
+'''
+
+def limit_file_size(ui, repo, node=None, **kwargs):
+ '''forbid files over a given size'''
+
+ # default limit is 1 MB
+ limit = int(ui.config('limit_file_size', 'maximum_file_size', 1024*1024))
+ existing_tip = context.changectx(repo, node).rev()
+ new_tip = context.changectx(repo, 'tip').rev()
+ for rev in xrange(existing_tip, new_tip + 1):
+ ctx = context.changectx(repo, rev)
+ for f in ctx.files():
+ fctx = ctx.filectx(f)
+ if fctx.size() > limit:
+ ui.write(_('file %s of %s is too large: %d > %d\n') % \
+ (f, ctx, fctx.size(), limit))
+ return True # This is invalid
+
+ return False # Things are OK.