Mercurial > hg
view mercurial/filelog.py @ 39559:07b58266bce3
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
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Wed, 05 Sep 2018 09:06:40 -0700 |
parents | 71575a1e197e |
children | 3e801ffd7269 |
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# filelog.py - file history class for mercurial # # Copyright 2005-2007 Matt Mackall <mpm@selenic.com> # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. from __future__ import absolute_import from . import ( error, repository, revlog, ) from .utils import ( interfaceutil, ) @interfaceutil.implementer(repository.ifilestorage) class filelog(object): def __init__(self, opener, path): self._revlog = revlog.revlog(opener, '/'.join(('data', path + '.i')), censorable=True) # full name of the user visible file, relative to the repository root self.filename = path self.index = self._revlog.index self.version = self._revlog.version self._generaldelta = self._revlog._generaldelta def __len__(self): return len(self._revlog) def __iter__(self): return self._revlog.__iter__() def revs(self, start=0, stop=None): return self._revlog.revs(start=start, stop=stop) def parents(self, node): return self._revlog.parents(node) def parentrevs(self, rev): return self._revlog.parentrevs(rev) def rev(self, node): return self._revlog.rev(node) def node(self, rev): return self._revlog.node(rev) def lookup(self, node): return self._revlog.lookup(node) def linkrev(self, rev): return self._revlog.linkrev(rev) def flags(self, rev): return self._revlog.flags(rev) def commonancestorsheads(self, node1, node2): return self._revlog.commonancestorsheads(node1, node2) def descendants(self, revs): return self._revlog.descendants(revs) def headrevs(self): return self._revlog.headrevs() def heads(self, start=None, stop=None): return self._revlog.heads(start, stop) def children(self, node): return self._revlog.children(node) def deltaparent(self, rev): return self._revlog.deltaparent(rev) def iscensored(self, rev): return self._revlog.iscensored(rev) def rawsize(self, rev): return self._revlog.rawsize(rev) def checkhash(self, text, node, p1=None, p2=None, rev=None): return self._revlog.checkhash(text, node, p1=p1, p2=p2, rev=rev) def revision(self, node, _df=None, raw=False): return self._revlog.revision(node, _df=_df, raw=raw) def revdiff(self, rev1, rev2): return self._revlog.revdiff(rev1, rev2) def emitrevisiondeltas(self, requests): return self._revlog.emitrevisiondeltas(requests) def addrevision(self, revisiondata, transaction, linkrev, p1, p2, node=None, flags=revlog.REVIDX_DEFAULT_FLAGS, cachedelta=None): return self._revlog.addrevision(revisiondata, transaction, linkrev, p1, p2, node=node, flags=flags, cachedelta=cachedelta) def addgroup(self, deltas, linkmapper, transaction, addrevisioncb=None): return self._revlog.addgroup(deltas, linkmapper, transaction, addrevisioncb=addrevisioncb) def getstrippoint(self, minlink): return self._revlog.getstrippoint(minlink) def strip(self, minlink, transaction): return self._revlog.strip(minlink, transaction) def files(self): return self._revlog.files() def checksize(self): return self._revlog.checksize() def read(self, node): t = self.revision(node) if not t.startswith('\1\n'): return t s = t.index('\1\n', 2) return t[s + 2:] def add(self, text, meta, transaction, link, p1=None, p2=None): if meta or text.startswith('\1\n'): text = revlog.packmeta(meta, text) return self.addrevision(text, transaction, link, p1, p2) def renamed(self, node): if self.parents(node)[0] != revlog.nullid: return False t = self.revision(node) m = revlog.parsemeta(t)[0] # copy and copyrev occur in pairs. In rare cases due to bugs, # one can occur without the other. if m and "copy" in m and "copyrev" in m: return (m["copy"], revlog.bin(m["copyrev"])) return False def size(self, rev): """return the size of a given revision""" # for revisions with renames, we have to go the slow way node = self.node(rev) if self.renamed(node): return len(self.read(node)) if self.iscensored(rev): return 0 # XXX if self.read(node).startswith("\1\n"), this returns (size+4) return self._revlog.size(rev) def cmp(self, node, text): """compare text with a given file revision returns True if text is different than what is stored. """ t = text if text.startswith('\1\n'): t = '\1\n\1\n' + text samehashes = not self._revlog.cmp(node, t) if samehashes: return False # censored files compare against the empty file if self.iscensored(self.rev(node)): return text != '' # renaming a file produces a different hash, even if the data # remains unchanged. Check if it's the case (slow): if self.renamed(node): t2 = self.read(node) return t2 != text return True @property def filename(self): return self._revlog.filename @filename.setter def filename(self, value): self._revlog.filename = value # TODO these aren't part of the interface and aren't internal methods. # Callers should be fixed to not use them. @property def indexfile(self): return self._revlog.indexfile @indexfile.setter def indexfile(self, value): self._revlog.indexfile = value @property def datafile(self): return self._revlog.datafile @property def opener(self): return self._revlog.opener def clone(self, tr, destrevlog, **kwargs): if not isinstance(destrevlog, filelog): raise error.ProgrammingError('expected filelog to clone()') return self._revlog.clone(tr, destrevlog._revlog, **kwargs) def start(self, rev): return self._revlog.start(rev) def end(self, rev): return self._revlog.end(rev) def length(self, rev): return self._revlog.length(rev) def compress(self, data): return self._revlog.compress(data) def _addrevision(self, *args, **kwargs): return self._revlog._addrevision(*args, **kwargs)