lfs: avoid quadratic performance in processing server responses This is also adapted from the Facebook repo[1]. Unlike there, we were already reading the download stream in chunks and immediately writing it to disk, so we basically avoided the problem on download. There shouldn't be a lot of data to read on upload, but it's better to get rid of this pattern. [1] https://github.com/facebookexperimental/eden/commit/82df66ffe97e21f3ee73dfec093c87500fc1f6a7 Differential Revision: https://phab.mercurial-scm.org/D7882

lfs: check content length after downloading content Adapted from the Facebook repo[1]. The intent is to distinguish between the connection dying and getting served a corrupt blob. The original message: HTTP makes no provision to tell your client that you failed halfway through producing your response and won't have the answer they're looking for. So, if a LFS server fails while producing a response, then we'll report an OID mismatch. We can do a little better and disambiguate between "the server sent us the wrong blob" (very scary) and "the server crashed" (merely annoying) by looking at the content length of the response we got back. If it's not what was advertised, we can reasonably safely assume the server crashed. [1] https://github.com/facebookexperimental/eden/commit/2a4a6fab4e882ed89b948bfc1e7d56d7c3c99dd2 Differential Revision: https://phab.mercurial-scm.org/D7881

lfs: rename a variable to clarify its use This is the response object, not a request. Differential Revision: https://phab.mercurial-scm.org/D7880

sha1dc: use proper string functions on Python 2/3 PyString_FromStringAndSize doesn't exist on Python 3: we need to use PyUnicode_FromStringAndSize. The extension now compiles without warnings on Python 2 and 3. Differential Revision: https://phab.mercurial-scm.org/D7878