[PATCH 04 of 11] httppeer: use compression engine API for decompressing responses
Gregory Szorc
gregory.szorc at gmail.com
Sun Nov 20 22:23:41 UTC 2016
# HG changeset patch
# User Gregory Szorc <gregory.szorc at gmail.com>
# Date 1479678953 28800
# Sun Nov 20 13:55:53 2016 -0800
# Node ID da1caf5b703a641f0167ece15fdff167a1343ec1
# Parent 0bef0b8fb9f44ed8568df6cfeabf162aa12b211e
httppeer: use compression engine API for decompressing responses
In preparation for supporting multiple compression formats on the
wire protocol, we need all users of the wire protocol to use
compression engine APIs.
This commit ports the HTTP wire protocol client to use the
compression engine API.
The code for handling the HTTPException is a bit hacky. Essentially,
HTTPException could be thrown by any read() from the socket. However,
as part of porting the API, we no longer have a generator wrapping
the socket and we don't have a single place where we can trap the
exception. We solve this by introducing a proxy class that intercepts
read() and converts the exception appropriately.
In the future, we could introduce a new compression engine API that
supports emitting a generator of decompressed chunks. This would
eliminate the need for the proxy class. As I said when I introduced
the decompressorreader() API, I'm not fond of it and would support
transitioning to something better. This can be done as a follow-up,
preferably once all the code is using the compression engine API and
we have a better idea of the API needs of all the consumers.
diff --git a/mercurial/httppeer.py b/mercurial/httppeer.py
--- a/mercurial/httppeer.py
+++ b/mercurial/httppeer.py
@@ -12,7 +12,6 @@ import errno
import os
import socket
import tempfile
-import zlib
from .i18n import _
from .node import nullid
@@ -30,16 +29,26 @@ httplib = util.httplib
urlerr = util.urlerr
urlreq = util.urlreq
-def zgenerator(f):
- zd = zlib.decompressobj()
+# FUTURE: consider refactoring this API to use generators. This will
+# require a compression engine API to emit generators.
+def decompressresponse(response, engine):
try:
- for chunk in util.filechunkiter(f):
- while chunk:
- yield zd.decompress(chunk, 2**18)
- chunk = zd.unconsumed_tail
+ reader = engine.decompressorreader(response)
except httplib.HTTPException:
raise IOError(None, _('connection ended unexpectedly'))
- yield zd.flush()
+
+ # We need to wrap reader.read() so HTTPException on subsequent
+ # reads is also converted.
+ origread = reader.read
+ class readerproxy(reader.__class__):
+ def read(self, *args, **kwargs):
+ try:
+ return origread(*args, **kwargs)
+ except httplib.HTTPException:
+ raise IOError(None, _('connection ended unexpectedly'))
+
+ reader.__class__ = readerproxy
+ return reader
class httppeer(wireproto.wirepeer):
def __init__(self, ui, path):
@@ -202,7 +211,7 @@ class httppeer(wireproto.wirepeer):
(safeurl, version))
if _compressible:
- return util.chunkbuffer(zgenerator(resp))
+ return decompressresponse(resp, util.compengines['zlib'])
return resp
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