hgext/show.py

show: construct changeset templater during dispatch

Previously, we constructed a formatter from a specific template
topic. Then from show() we reached into the internals of the
formatter to resolve a template string to be used to construct
a changeset templater.

A downside to this approach was it limited us to having the
entire template defined in a single entry in the map file. You
couldn't reference other entries in the map file and this would
lead to long templates and redundancy in the map file.

This commit teaches @showview how to instantiate a changeset
templater so we can construct a templater with full access to
the map file. To prove it works, we've split "showwork" into
components.

# show.py - Extension implementing `hg show`
#
# Copyright 2017 Gregory Szorc <[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.

"""unified command to show various repository information (EXPERIMENTAL)

This extension provides the :hg:`show` command, which provides a central
command for displaying commonly-accessed repository data and views of that
data.
"""

from __future__ import absolute_import

from mercurial.i18n import _
from mercurial.node import nullrev
from mercurial import (
    cmdutil,
    error,
    formatter,
    graphmod,
    pycompat,
    registrar,
    revset,
    revsetlang,
)

# 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'

cmdtable = {}
command = registrar.command(cmdtable)
revsetpredicate = registrar.revsetpredicate()

class showcmdfunc(registrar._funcregistrarbase):
    """Register a function to be invoked for an `hg show <thing>`."""

    # Used by _formatdoc().
    _docformat = '%s -- %s'

    def _extrasetup(self, name, func, fmtopic=None, csettopic=None):
        """Called with decorator arguments to register a show view.

        ``name`` is the sub-command name.

        ``func`` is the function being decorated.

        ``fmtopic`` is the topic in the style that will be rendered for
        this view.

        ``csettopic`` is the topic in the style to be used for a changeset
        printer.

        If ``fmtopic`` is specified, the view function will receive a
        formatter instance. If ``csettopic`` is specified, the view
        function will receive a changeset printer.
        """
        func._fmtopic = fmtopic
        func._csettopic = csettopic

showview = showcmdfunc()

@command('show', [
    # TODO: Switch this template flag to use cmdutil.formatteropts if
    # 'hg show' becomes stable before --template/-T is stable. For now,
    # we are putting it here without the '(EXPERIMENTAL)' flag because it
    # is an important part of the 'hg show' user experience and the entire
    # 'hg show' experience is experimental.
    ('T', 'template', '', ('display with template'), _('TEMPLATE')),
    ], _('VIEW'))
def show(ui, repo, view=None, template=None):
    """show various repository information

    A requested view of repository data is displayed.

    If no view is requested, the list of available views is shown and the
    command aborts.

    .. note::

       There are no backwards compatibility guarantees for the output of this
       command. Output may change in any future Mercurial release.

       Consumers wanting stable command output should specify a template via
       ``-T/--template``.

    List of available views:
    """
    if ui.plain() and not template:
        hint = _('invoke with -T/--template to control output format')
        raise error.Abort(_('must specify a template in plain mode'), hint=hint)

    views = showview._table

    if not view:
        ui.pager('show')
        # TODO consider using formatter here so available views can be
        # rendered to custom format.
        ui.write(_('available views:\n'))
        ui.write('\n')

        for name, func in sorted(views.items()):
            ui.write(('%s\n') % func.__doc__)

        ui.write('\n')
        raise error.Abort(_('no view requested'),
                          hint=_('use "hg show VIEW" to choose a view'))

    # TODO use same logic as dispatch to perform prefix matching.
    if view not in views:
        raise error.Abort(_('unknown view: %s') % view,
                          hint=_('run "hg show" to see available views'))

    template = template or 'show'

    fn = views[view]
    ui.pager('show')

    if fn._fmtopic:
        fmtopic = 'show%s' % fn._fmtopic
        with ui.formatter(fmtopic, {'template': template}) as fm:
            return fn(ui, repo, fm)
    elif fn._csettopic:
        ref = 'show%s' % fn._csettopic
        spec = formatter.lookuptemplate(ui, ref, template)
        displayer = cmdutil.changeset_templater(ui, repo, spec, buffered=True)
        return fn(ui, repo, displayer)
    else:
        return fn(ui, repo)

@showview('bookmarks', fmtopic='bookmarks')
def showbookmarks(ui, repo, fm):
    """bookmarks and their associated changeset"""
    marks = repo._bookmarks
    if not len(marks):
        # This is a bit hacky. Ideally, templates would have a way to
        # specify an empty output, but we shouldn't corrupt JSON while
        # waiting for this functionality.
        if not isinstance(fm, formatter.jsonformatter):
            ui.write(_('(no bookmarks set)\n'))
        return

    active = repo._activebookmark
    longestname = max(len(b) for b in marks)
    # TODO consider exposing longest shortest(node).

    for bm, node in sorted(marks.items()):
        fm.startitem()
        fm.context(ctx=repo[node])
        fm.write('bookmark', '%s', bm)
        fm.write('node', fm.hexfunc(node), fm.hexfunc(node))
        fm.data(active=bm == active,
                longestbookmarklen=longestname)

@revsetpredicate('_underway([commitage[, headage]])')
def underwayrevset(repo, subset, x):
    args = revset.getargsdict(x, 'underway', 'commitage headage')
    if 'commitage' not in args:
        args['commitage'] = None
    if 'headage' not in args:
        args['headage'] = None

    # We assume callers of this revset add a topographical sort on the
    # result. This means there is no benefit to making the revset lazy
    # since the topographical sort needs to consume all revs.
    #
    # With this in mind, we build up the set manually instead of constructing
    # a complex revset. This enables faster execution.

    # Mutable changesets (non-public) are the most important changesets
    # to return. ``not public()`` will also pull in obsolete changesets if
    # there is a non-obsolete changeset with obsolete ancestors. This is
    # why we exclude obsolete changesets from this query.
    rs = 'not public() and not obsolete()'
    rsargs = []
    if args['commitage']:
        rs += ' and date(%s)'
        rsargs.append(revsetlang.getstring(args['commitage'],
                                           _('commitage requires a string')))

    mutable = repo.revs(rs, *rsargs)
    relevant = revset.baseset(mutable)

    # Add parents of mutable changesets to provide context.
    relevant += repo.revs('parents(%ld)', mutable)

    # We also pull in (public) heads if they a) aren't closing a branch
    # b) are recent.
    rs = 'head() and not closed()'
    rsargs = []
    if args['headage']:
        rs += ' and date(%s)'
        rsargs.append(revsetlang.getstring(args['headage'],
                                           _('headage requires a string')))

    relevant += repo.revs(rs, *rsargs)

    # Add working directory parent.
    wdirrev = repo['.'].rev()
    if wdirrev != nullrev:
        relevant += revset.baseset({wdirrev})

    return subset & relevant

@showview('work', csettopic='work')
def showwork(ui, repo, displayer):
    """changesets that aren't finished"""
    # TODO support date-based limiting when calling revset.
    revs = repo.revs('sort(_underway(), topo)')

    revdag = graphmod.dagwalker(repo, revs)

    ui.setconfig('experimental', 'graphshorten', True)
    cmdutil.displaygraph(ui, repo, revdag, displayer, graphmod.asciiedges)

# Adjust the docstring of the show command so it shows all registered views.
# This is a bit hacky because it runs at the end of module load. When moved
# into core or when another extension wants to provide a view, we'll need
# to do this more robustly.
# TODO make this more robust.
def _updatedocstring():
    longest = max(map(len, showview._table.keys()))
    entries = []
    for key in sorted(showview._table.keys()):
        entries.append(pycompat.sysstr('    %s   %s' % (
            key.ljust(longest), showview._table[key]._origdoc)))

    cmdtable['show'][0].__doc__ = pycompat.sysstr('%s\n\n%s\n    ') % (
        cmdtable['show'][0].__doc__.rstrip(),
        pycompat.sysstr('\n\n').join(entries))

_updatedocstring()