view hgext/hgk.py @ 35976:48a3a9283f09

sshpeer: initial definition and implementation of new SSH protocol

The existing SSH protocol has several design flaws. Future commits
will elaborate on these flaws as new features are introduced
to combat these flaws. For now, hopefully you can take me for my
word that a ground up rewrite of the SSH protocol is needed.

This commit lays the foundation for a new SSH protocol by defining
a mechanism to upgrade the SSH transport channel away from the
default (version 1) protocol to something modern (which we'll call
"version 2" for now).

This upgrade process is detailed in the internals documentation
for the wire protocol. The gist of it is the client sends a
request line preceding the "hello" command/line which basically
says "I'm requesting an upgrade: here's what I support." If the
server recognizes that line, it processes the upgrade request and
the transport channel is switched to use the new version of the
protocol. If not, it sends an empty response, which is how all
Mercurial SSH servers from the beginning of time reacted to unknown
commands. The upgrade request is effectively ignored and the client
continues to use the existing version of the protocol as if nothing
happened.

The new version of the SSH protocol is completely identical to
version 1 aside from the upgrade dance and the bytes that follow.
The immediate bytes that follow the protocol switch are defined to
be a length framed "capabilities: " line containing the remote's
advertised capabilities. In reality, this looks very similar to
what the "hello" response would look like. But it will evolve
quickly.

The methodology by which the protocol will evolve is important.

I'm not going to introduce the new protocol all at once. That would
likely lead to endless bike shedding and forward progress would
stall. Instead, I intend to tricle out new features and diversions
from the existing protocol in small, incremental changes.

To support the gradual evolution of the protocol, the on-the-wire
advertised protocol name contains an "exp" to denote "experimental"
and a 4 digit field to capture the sub-version of the protocol.
Whenever we make a BC change to the wire protocol, we can increment
this version and lock out all older clients because it will appear
as a completely different protocol version. This means we can incur
as many breaking changes as we want. We don't have to commit to
supporting any one feature or idea for a long period of time. We
can even evolve the handshake mechanism, because that is defined
as being an implementation detail of the negotiated protocol version!
Hopefully this lowers the barrier to accepting changes to the
protocol and for experimenting with "radical" ideas during its
development.

In core, sshpeer received most of the attention. We haven't even
implemented the server bits for the new protocol in core yet.
Instead, we add very primitive support to our test server, mainly
just to exercise the added code paths in sshpeer.

Differential Revision: https://phab.mercurial-scm.org/D2061

# no-check-commit because of required foo_bar naming

# Minimal support for git commands on an hg repository
#
# Copyright 2005, 2006 Chris Mason <[e-mail]>
#
# 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,
    util,
)

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']:
            try:
                line = util.bytesinput(ui.fin, ui.fout).split(' ')
                node1 = line[0]
                if len(line) > 1:
                    node2 = line[1]
                else:
                    node2 = None
            except EOFError:
                break
        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 %s %s\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']:
        try:
            (type, r) = util.bytesinput(ui.fin, ui.fout).split(' ')
            prefix = "    "
        except EOFError:
            return

    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']:
            try:
                (type, r) = util.bytesinput(ui.fin, ui.fout).split(' ')
            except EOFError:
                break
        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 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 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 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')