--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hgext/remotefilelog/lz4wrapper.py	Thu Sep 27 13:03:19 2018 -0400
@@ -0,0 +1,37 @@
+from __future__ import absolute_import
+
+from mercurial.i18n import _
+from mercurial import (
+    demandimport,
+    error,
+    util,
+)
+if util.safehasattr(demandimport, 'IGNORES'):
+    # Since 670eb4fa1b86
+    demandimport.IGNORES.update(['pkgutil', 'pkg_resources', '__main__'])
+else:
+    demandimport.ignore.extend(['pkgutil', 'pkg_resources', '__main__'])
+
+def missing(*args, **kwargs):
+    raise error.Abort(_('remotefilelog extension requires lz4 support'))
+
+lz4compress = lzcompresshc = lz4decompress = missing
+
+with demandimport.deactivated():
+    import lz4
+
+    try:
+        # newer python-lz4 has these functions deprecated as top-level ones,
+        # so we are trying to import from lz4.block first
+        def _compressHC(*args, **kwargs):
+            return lz4.block.compress(*args, mode='high_compression', **kwargs)
+        lzcompresshc = _compressHC
+        lz4compress = lz4.block.compress
+        lz4decompress = lz4.block.decompress
+    except AttributeError:
+        try:
+            lzcompresshc = lz4.compressHC
+            lz4compress = lz4.compress
+            lz4decompress = lz4.decompress
+        except AttributeError:
+            pass