localrepo: iteratively derive local repository type
This commit implements the dynamic local repository type derivation
that was explained in the recent commit
bfeab472e3c0 "localrepo: create new function for instantiating a local
repo object."
Instead of a static localrepository class/type which must be customized
after construction, we now dynamically construct a type by building up
base classes/types to represent specific repository interfaces.
Conceptually, the end state is similar to what was happening when
various extensions would monkeypatch the __class__ of newly-constructed
repo instances. However, the approach is inverted. Instead of making
the instance then customizing it, we do the customization up front
by influencing the behavior of the type then we instantiate that
custom type.
This approach gives us much more flexibility. For example, we can
use completely separate classes for implementing different aspects
of the repository. For example, we could have one class representing
revlog-based file storage and another representing non-revlog based
file storage. When then choose which implementation to use based on
the presence of repo requirements.
A concern with this approach is that it creates a lot more types
and complexity and that complexity adds overhead. Yes, it is true that
this approach will result in more types being created. Yes, this is
more complicated than traditional "instantiate a static type." However,
I believe the alternatives to supporting alternate storage backends
are just as complicated. (Before I arrived at this solution, I had
patches storing factory functions on local repo instances for e.g.
constructing a file storage instance. We ended up having a handful
of these. And this was logically identical to assigning custom
methods. Since we were logically changing the type of the instance,
I figured it would be better to just use specialized types instead
of introducing levels of abstraction at run-time.)
On the performance front, I don't believe that having N base classes
has any significant performance overhead compared to just a single base
class. Intuition says that Python will need to iterate the base classes
to find an attribute. However, CPython caches method lookups: as long as
the __class__ or MRO isn't changing, method attribute lookup should be
constant time after first access. And non-method attributes are stored
in __dict__, of which there is only 1 per object, so the number of
base classes for __dict__ is irrelevant.
Anyway, this commit splits up the monolithic completelocalrepository
interface into sub-interfaces: 1 for file storage and 1 representing
everything else.
We've taught ``makelocalrepository()`` to call a series of factory
functions which will produce types implementing specific interfaces.
It then calls type() to create a new type from the built-up list of
base types.
This commit should be considered a start and not the end state. I
suspect we'll hit a number of problems as we start to implement
alternate storage backends:
* Passing custom arguments to __init__ and setting custom attributes
on __dict__.
* Customizing the set of interfaces that are needed. e.g. the
"readonly" intent could translate to not requesting an interface
providing methods related to writing.
* More ergonomic way for extensions to insert themselves so their
callbacks aren't unconditionally called.
* Wanting to modify vfs instances, other arguments passed to __init__.
That being said, this code is usable in its current state and I'm
convinced future commits will demonstrate the value in this approach.
Differential Revision: https://phab.mercurial-scm.org/D4642
# Minimal support for git commands on an hg repository
#
# Copyright 2005, 2006 Chris Mason <mason@suse.com>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
'''browse the repository in a graphical way
The hgk extension allows browsing the history of a repository in a
graphical way. It requires Tcl/Tk version 8.4 or later. (Tcl/Tk is not
distributed with Mercurial.)
hgk consists of two parts: a Tcl script that does the displaying and
querying of information, and an extension to Mercurial named hgk.py,
which provides hooks for hgk to get information. hgk can be found in
the contrib directory, and the extension is shipped in the hgext
repository, and needs to be enabled.
The :hg:`view` command will launch the hgk Tcl script. For this command
to work, hgk must be in your search path. Alternately, you can specify
the path to hgk in your configuration file::
[hgk]
path = /location/of/hgk
hgk can make use of the extdiff extension to visualize revisions.
Assuming you had already configured extdiff vdiff command, just add::
[hgk]
vdiff=vdiff
Revisions context menu will now display additional entries to fire
vdiff on hovered and selected revisions.
'''
from __future__ import absolute_import
import os
from mercurial.i18n import _
from mercurial.node import (
nullid,
nullrev,
short,
)
from mercurial import (
commands,
obsolete,
patch,
pycompat,
registrar,
scmutil,
)
cmdtable = {}
command = registrar.command(cmdtable)
# Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for
# extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
# be specifying the version(s) of Mercurial they are tested with, or
# leave the attribute unspecified.
testedwith = 'ships-with-hg-core'
configtable = {}
configitem = registrar.configitem(configtable)
configitem('hgk', 'path',
default='hgk',
)
@command('debug-diff-tree',
[('p', 'patch', None, _('generate patch')),
('r', 'recursive', None, _('recursive')),
('P', 'pretty', None, _('pretty')),
('s', 'stdin', None, _('stdin')),
('C', 'copy', None, _('detect copies')),
('S', 'search', "", _('search'))],
('[OPTION]... NODE1 NODE2 [FILE]...'),
inferrepo=True)
def difftree(ui, repo, node1=None, node2=None, *files, **opts):
"""diff trees from two commits"""
def __difftree(repo, node1, node2, files=None):
assert node2 is not None
if files is None:
files = []
mmap = repo[node1].manifest()
mmap2 = repo[node2].manifest()
m = scmutil.match(repo[node1], files)
modified, added, removed = repo.status(node1, node2, m)[:3]
empty = short(nullid)
for f in modified:
# TODO get file permissions
ui.write((":100664 100664 %s %s M\t%s\t%s\n") %
(short(mmap[f]), short(mmap2[f]), f, f))
for f in added:
ui.write((":000000 100664 %s %s N\t%s\t%s\n") %
(empty, short(mmap2[f]), f, f))
for f in removed:
ui.write((":100664 000000 %s %s D\t%s\t%s\n") %
(short(mmap[f]), empty, f, f))
##
while True:
if opts[r'stdin']:
line = ui.fin.readline()
if not line:
break
line = line.rstrip(pycompat.oslinesep).split(b' ')
node1 = line[0]
if len(line) > 1:
node2 = line[1]
else:
node2 = None
node1 = repo.lookup(node1)
if node2:
node2 = repo.lookup(node2)
else:
node2 = node1
node1 = repo.changelog.parents(node1)[0]
if opts[r'patch']:
if opts[r'pretty']:
catcommit(ui, repo, node2, "")
m = scmutil.match(repo[node1], files)
diffopts = patch.difffeatureopts(ui)
diffopts.git = True
chunks = patch.diff(repo, node1, node2, match=m,
opts=diffopts)
for chunk in chunks:
ui.write(chunk)
else:
__difftree(repo, node1, node2, files=files)
if not opts[r'stdin']:
break
def catcommit(ui, repo, n, prefix, ctx=None):
nlprefix = '\n' + prefix
if ctx is None:
ctx = repo[n]
# use ctx.node() instead ??
ui.write(("tree %s\n" % short(ctx.changeset()[0])))
for p in ctx.parents():
ui.write(("parent %s\n" % p))
date = ctx.date()
description = ctx.description().replace("\0", "")
ui.write(("author %s %d %d\n" % (ctx.user(), int(date[0]), date[1])))
if 'committer' in ctx.extra():
ui.write(("committer %s\n" % ctx.extra()['committer']))
ui.write(("revision %d\n" % ctx.rev()))
ui.write(("branch %s\n" % ctx.branch()))
if obsolete.isenabled(repo, obsolete.createmarkersopt):
if ctx.obsolete():
ui.write(("obsolete\n"))
ui.write(("phase %s\n\n" % ctx.phasestr()))
if prefix != "":
ui.write("%s%s\n" % (prefix,
description.replace('\n', nlprefix).strip()))
else:
ui.write(description + "\n")
if prefix:
ui.write('\0')
@command('debug-merge-base', [], _('REV REV'))
def base(ui, repo, node1, node2):
"""output common ancestor information"""
node1 = repo.lookup(node1)
node2 = repo.lookup(node2)
n = repo.changelog.ancestor(node1, node2)
ui.write(short(n) + "\n")
@command('debug-cat-file',
[('s', 'stdin', None, _('stdin'))],
_('[OPTION]... TYPE FILE'),
inferrepo=True)
def catfile(ui, repo, type=None, r=None, **opts):
"""cat a specific revision"""
# in stdin mode, every line except the commit is prefixed with two
# spaces. This way the our caller can find the commit without magic
# strings
#
prefix = ""
if opts[r'stdin']:
line = ui.fin.readline()
if not line:
return
(type, r) = line.rstrip(pycompat.oslinesep).split(b' ')
prefix = " "
else:
if not type or not r:
ui.warn(_("cat-file: type or revision not supplied\n"))
commands.help_(ui, 'cat-file')
while r:
if type != "commit":
ui.warn(_("aborting hg cat-file only understands commits\n"))
return 1
n = repo.lookup(r)
catcommit(ui, repo, n, prefix)
if opts[r'stdin']:
line = ui.fin.readline()
if not line:
break
(type, r) = line.rstrip(pycompat.oslinesep).split(b' ')
else:
break
# git rev-tree is a confusing thing. You can supply a number of
# commit sha1s on the command line, and it walks the commit history
# telling you which commits are reachable from the supplied ones via
# a bitmask based on arg position.
# you can specify a commit to stop at by starting the sha1 with ^
def revtree(ui, args, repo, full="tree", maxnr=0, parents=False):
def chlogwalk():
count = len(repo)
i = count
l = [0] * 100
chunk = 100
while True:
if chunk > i:
chunk = i
i = 0
else:
i -= chunk
for x in pycompat.xrange(chunk):
if i + x >= count:
l[chunk - x:] = [0] * (chunk - x)
break
if full is not None:
if (i + x) in repo:
l[x] = repo[i + x]
l[x].changeset() # force reading
else:
if (i + x) in repo:
l[x] = 1
for x in pycompat.xrange(chunk - 1, -1, -1):
if l[x] != 0:
yield (i + x, full is not None and l[x] or None)
if i == 0:
break
# calculate and return the reachability bitmask for sha
def is_reachable(ar, reachable, sha):
if len(ar) == 0:
return 1
mask = 0
for i in pycompat.xrange(len(ar)):
if sha in reachable[i]:
mask |= 1 << i
return mask
reachable = []
stop_sha1 = []
want_sha1 = []
count = 0
# figure out which commits they are asking for and which ones they
# want us to stop on
for i, arg in enumerate(args):
if arg.startswith('^'):
s = repo.lookup(arg[1:])
stop_sha1.append(s)
want_sha1.append(s)
elif arg != 'HEAD':
want_sha1.append(repo.lookup(arg))
# calculate the graph for the supplied commits
for i, n in enumerate(want_sha1):
reachable.append(set())
visit = [n]
reachable[i].add(n)
while visit:
n = visit.pop(0)
if n in stop_sha1:
continue
for p in repo.changelog.parents(n):
if p not in reachable[i]:
reachable[i].add(p)
visit.append(p)
if p in stop_sha1:
continue
# walk the repository looking for commits that are in our
# reachability graph
for i, ctx in chlogwalk():
if i not in repo:
continue
n = repo.changelog.node(i)
mask = is_reachable(want_sha1, reachable, n)
if mask:
parentstr = ""
if parents:
pp = repo.changelog.parents(n)
if pp[0] != nullid:
parentstr += " " + short(pp[0])
if pp[1] != nullid:
parentstr += " " + short(pp[1])
if not full:
ui.write("%s%s\n" % (short(n), parentstr))
elif full == "commit":
ui.write("%s%s\n" % (short(n), parentstr))
catcommit(ui, repo, n, ' ', ctx)
else:
(p1, p2) = repo.changelog.parents(n)
(h, h1, h2) = map(short, (n, p1, p2))
(i1, i2) = map(repo.changelog.rev, (p1, p2))
date = ctx.date()[0]
ui.write("%s %s:%s" % (date, h, mask))
mask = is_reachable(want_sha1, reachable, p1)
if i1 != nullrev and mask > 0:
ui.write("%s:%s " % (h1, mask)),
mask = is_reachable(want_sha1, reachable, p2)
if i2 != nullrev and mask > 0:
ui.write("%s:%s " % (h2, mask))
ui.write("\n")
if maxnr and count >= maxnr:
break
count += 1
# git rev-list tries to order things by date, and has the ability to stop
# at a given commit without walking the whole repo. TODO add the stop
# parameter
@command('debug-rev-list',
[('H', 'header', None, _('header')),
('t', 'topo-order', None, _('topo-order')),
('p', 'parents', None, _('parents')),
('n', 'max-count', 0, _('max-count'))],
('[OPTION]... REV...'))
def revlist(ui, repo, *revs, **opts):
"""print revisions"""
if opts['header']:
full = "commit"
else:
full = None
copy = [x for x in revs]
revtree(ui, copy, repo, full, opts[r'max_count'], opts[r'parents'])
@command('view',
[('l', 'limit', '',
_('limit number of changes displayed'), _('NUM'))],
_('[-l LIMIT] [REVRANGE]'))
def view(ui, repo, *etc, **opts):
"start interactive history viewer"
opts = pycompat.byteskwargs(opts)
os.chdir(repo.root)
optstr = ' '.join(['--%s %s' % (k, v) for k, v in opts.iteritems() if v])
if repo.filtername is None:
optstr += '--hidden'
cmd = ui.config("hgk", "path") + " %s %s" % (optstr, " ".join(etc))
ui.debug("running %s\n" % cmd)
ui.system(cmd, blockedtag='hgk_view')