##// END OF EJS Templates
wireprotov2: implement commands as a generator of objects...
wireprotov2: implement commands as a generator of objects Previously, wire protocol version 2 inherited version 1's model of having separate types to represent the results of different wire protocol commands. As I implemented more powerful commands in future commits, I found I was using a common pattern of returning a special type to hold a generator. This meant the command function required a closure to do most of the work. That made logic flow more difficult to follow. I also noticed that many commands were effectively a sequence of objects to be CBOR encoded. I think it makes sense to define version 2 commands as generators. This way, commands can simply emit the data structures they wish to send to the client. This eliminates the need for a closure in command functions and removes encoding from the bodies of commands. As part of this commit, the handling of response objects has been moved into the serverreactor class. This puts the reactor in the driver's seat with regards to CBOR encoding and error handling. Having error handling in the function that emits frames is particularly important because exceptions in that function can lead to things getting in a bad state: I'm fairly certain that uncaught exceptions in the frame generator were causing deadlocks. I also introduced a dedicated error type for explicit error reporting in command handlers. This will be used in subsequent commits. There's still a bit of work to be done here, especially around formalizing the error handling "protocol." I've added yet another TODO to track this so we don't forget. Test output changed because we're using generators and no longer know we are at the end of the data until we hit the end of the generator. This means we can't emit the end-of-stream flag until we've exhausted the generator. Hence the introduction of 0-sized end-of-stream frames. Differential Revision: https://phab.mercurial-scm.org/D4472

File last commit:

r37454:9d4f09bf default
r39595:07b58266 default
Show More
flagprocessorext.py
136 lines | 3.7 KiB | text/x-python | PythonLexer
# coding=UTF-8
from __future__ import absolute_import
import base64
import zlib
from mercurial import (
changegroup,
exchange,
extensions,
revlog,
util,
)
# Test only: These flags are defined here only in the context of testing the
# behavior of the flag processor. The canonical way to add flags is to get in
# touch with the community and make them known in revlog.
REVIDX_NOOP = (1 << 3)
REVIDX_BASE64 = (1 << 2)
REVIDX_GZIP = (1 << 1)
REVIDX_FAIL = 1
def validatehash(self, text):
return True
def bypass(self, text):
return False
def noopdonothing(self, text):
return (text, True)
def b64encode(self, text):
return (base64.b64encode(text), False)
def b64decode(self, text):
return (base64.b64decode(text), True)
def gzipcompress(self, text):
return (zlib.compress(text), False)
def gzipdecompress(self, text):
return (zlib.decompress(text), True)
def supportedoutgoingversions(orig, repo):
versions = orig(repo)
versions.discard(b'01')
versions.discard(b'02')
versions.add(b'03')
return versions
def allsupportedversions(orig, ui):
versions = orig(ui)
versions.add(b'03')
return versions
def makewrappedfile(obj):
class wrappedfile(obj.__class__):
def addrevision(self, text, transaction, link, p1, p2,
cachedelta=None, node=None,
flags=revlog.REVIDX_DEFAULT_FLAGS):
if b'[NOOP]' in text:
flags |= REVIDX_NOOP
if b'[BASE64]' in text:
flags |= REVIDX_BASE64
if b'[GZIP]' in text:
flags |= REVIDX_GZIP
# This addrevision wrapper is meant to add a flag we will not have
# transforms registered for, ensuring we handle this error case.
if b'[FAIL]' in text:
flags |= REVIDX_FAIL
return super(wrappedfile, self).addrevision(text, transaction, link,
p1, p2,
cachedelta=cachedelta,
node=node,
flags=flags)
obj.__class__ = wrappedfile
def reposetup(ui, repo):
class wrappingflagprocessorrepo(repo.__class__):
def file(self, f):
orig = super(wrappingflagprocessorrepo, self).file(f)
makewrappedfile(orig)
return orig
repo.__class__ = wrappingflagprocessorrepo
def extsetup(ui):
# Enable changegroup3 for flags to be sent over the wire
wrapfunction = extensions.wrapfunction
wrapfunction(changegroup,
'supportedoutgoingversions',
supportedoutgoingversions)
wrapfunction(changegroup,
'allsupportedversions',
allsupportedversions)
# Teach revlog about our test flags
flags = [REVIDX_NOOP, REVIDX_BASE64, REVIDX_GZIP, REVIDX_FAIL]
revlog.REVIDX_KNOWN_FLAGS |= util.bitsfrom(flags)
revlog.REVIDX_FLAGS_ORDER.extend(flags)
# Teach exchange to use changegroup 3
for k in exchange._bundlespeccontentopts.keys():
exchange._bundlespeccontentopts[k]["cg.version"] = "03"
# Register flag processors for each extension
revlog.addflagprocessor(
REVIDX_NOOP,
(
noopdonothing,
noopdonothing,
validatehash,
)
)
revlog.addflagprocessor(
REVIDX_BASE64,
(
b64decode,
b64encode,
bypass,
),
)
revlog.addflagprocessor(
REVIDX_GZIP,
(
gzipdecompress,
gzipcompress,
bypass
)
)