view contrib/simplemerge @ 39862:5a9ab91e0a45

revlog: new API to emit revision data

I recently refactored changegroup generation code to make it more
storage agnostic. I made significant progress. But there is still
a bit of work to be done. Specifically:

* Changegroup code is looking at low-level storage attributes to
  influence sorting. Sorting should be done at the storage layer.
* The linknode lookup and sorting code for ellipsis is very
  complicated.
* Linknodes are just generally wonky because e.g. file storage doesn't
  know how to translate a linkrev to a changelog node.
* We regressed performance when introducing the request-response
  objects.

Having thought about this problem a bit, I think I've come up with
a better interface for emitting revision deltas.

This commit defines and implements that interface. See the docstring
in repository.py for more info.

This API adds 3 notable features over the previous one.

First, it defers node ordering to the storage implementation in
the common case but allows overriding as necessary. We have a
facility for requesting an exact ordering (used in ellipsis
mode). We have another facility for storage order (used for changelog).

Second, we have an argument specifying assumptions about parents
revisions. This can be used to force a fulltext revision when we
don't know the receiver has a parent revision to delta against.

Third, we can control whether revision data is emitted. This makes
the API suitable as a generic "index data retrieval" API as well
as for producing revision deltas - possibly in the same operation!

The new API is much simpler: we no longer need a complicated "request"
object to encapsulate the delta generation request. I'm optimistic
this will restore performance loss associated with
emitrevisiondeltas().

Storage unit tests for the new API have been implemented.

Future commits will port existing consumers of emitrevisiondeltas()
to the new API then remove emitrevisiondeltas().

Differential Revision: https://phab.mercurial-scm.org/D4722

#!/usr/bin/env python
from __future__ import absolute_import

import getopt
import sys

import hgdemandimport
hgdemandimport.enable()

from mercurial.i18n import _
from mercurial import (
    context,
    error,
    fancyopts,
    pycompat,
    simplemerge,
    ui as uimod,
)
from mercurial.utils import (
    procutil,
)

options = [(b'L', b'label', [], _(b'labels to use on conflict markers')),
           (b'a', b'text', None, _(b'treat all files as text')),
           (b'p', b'print', None,
            _(b'print results instead of overwriting LOCAL')),
           (b'', b'no-minimal', None, _(b'no effect (DEPRECATED)')),
           (b'h', b'help', None, _(b'display help and exit')),
           (b'q', b'quiet', None, _(b'suppress output'))]

usage = _('''simplemerge [OPTS] LOCAL BASE OTHER

    Simple three-way file merge utility with a minimal feature set.

    Apply to LOCAL the changes necessary to go from BASE to OTHER.

    By default, LOCAL is overwritten with the results of this operation.
''')

class ParseError(Exception):
    """Exception raised on errors in parsing the command line."""

def showhelp():
    sys.stdout.write(usage)
    sys.stdout.write(b'\noptions:\n')

    out_opts = []
    for shortopt, longopt, default, desc in options:
        out_opts.append((b'%2s%s' % (shortopt and b'-%s' % shortopt,
                                     longopt and b' --%s' % longopt),
                         b'%s' % desc))
    opts_len = max([len(opt[0]) for opt in out_opts])
    for first, second in out_opts:
        sys.stdout.write(b' %-*s  %s\n' % (opts_len, first, second))

try:
    for fp in (sys.stdin, sys.stdout, sys.stderr):
        procutil.setbinary(fp)

    opts = {}
    try:
        args = fancyopts.fancyopts(sys.argv[1:], options, opts)
    except getopt.GetoptError as e:
        raise ParseError(e)
    if opts[b'help']:
        showhelp()
        sys.exit(0)
    if len(args) != 3:
            raise ParseError(_(b'wrong number of arguments'))
    local, base, other = args
    sys.exit(simplemerge.simplemerge(uimod.ui.load(),
                                     context.arbitraryfilectx(local),
                                     context.arbitraryfilectx(base),
                                     context.arbitraryfilectx(other),
                                     **pycompat.strkwargs(opts)))
except ParseError as e:
    sys.stdout.write(b"%s: %s\n" % (sys.argv[0], e))
    showhelp()
    sys.exit(1)
except error.Abort as e:
    sys.stderr.write(b"abort: %s\n" % e)
    sys.exit(255)
except KeyboardInterrupt:
    sys.exit(255)