[PATCH 3 of 3] lfs: add an optional size limit when downloading a blob

[Matt Harbison]

# HG changeset patch
# User Matt Harbison <matt_harbison at yahoo.com>
# Date 1519277492 18000
#      Thu Feb 22 00:31:32 2018 -0500
# Node ID 36bfb2fc865b1d6024b943bece407970c4d61112
# Parent  7a6042e238b7a90ce1d158395c42937cb0f7298c
lfs: add an optional size limit when downloading a blob

The server hangs when it tries to read more than Content-Length bytes in the PUT
handler.

diff --git a/hgext/lfs/blobstore.py b/hgext/lfs/blobstore.py
--- a/hgext/lfs/blobstore.py
+++ b/hgext/lfs/blobstore.py
@@ -114,13 +114,13 @@
 
         return self.vfs(oid, 'rb')
 
-    def download(self, oid, src):
+    def download(self, oid, src, limit=None):
         """Read the blob from the remote source in chunks, verify the content,
         and write to this local blobstore."""
         sha256 = hashlib.sha256()
 
         with self.vfs(oid, 'wb', atomictemp=True) as fp:
-            for chunk in util.filechunkiter(src, size=1048576):
+            for chunk in util.filechunkiter(src, size=1048576, limit=limit):
                 fp.write(chunk)
                 sha256.update(chunk)