view hgext/fastannotate/support.py @ 42200:69921d02daaf

peer: introduce a limitedarguments attributes

When set to True, it signal that the peer cannot receive too larges arguments
and that algorithm must adapt. This should only be True for http peer that does
not support argument passed as "post".

This will be useful to unlock better discovery performance in the next
changesets.

I am using a dedicated argument because this is not really a usual
"capabilities" things. An alternative approach would be to adds a
"large-arguments" to all peer, but the http peers. That seemed a bit too hacky
to me.

# Copyright 2016-present Facebook. All Rights Reserved.
#
# support: fastannotate support for hgweb, and filectx
#
# 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 mercurial import (
    context as hgcontext,
    dagop,
    extensions,
    hgweb,
    patch,
    util,
)

from . import (
    context,
    revmap,
)

class _lazyfctx(object):
    """delegates to fctx but do not construct fctx when unnecessary"""

    def __init__(self, repo, node, path):
        self._node = node
        self._path = path
        self._repo = repo

    def node(self):
        return self._node

    def path(self):
        return self._path

    @util.propertycache
    def _fctx(self):
        return context.resolvefctx(self._repo, self._node, self._path)

    def __getattr__(self, name):
        return getattr(self._fctx, name)

def _convertoutputs(repo, annotated, contents):
    """convert fastannotate outputs to vanilla annotate format"""
    # fastannotate returns: [(nodeid, linenum, path)], [linecontent]
    # convert to what fctx.annotate returns: [annotateline]
    results = []
    fctxmap = {}
    annotateline = dagop.annotateline
    for i, (hsh, linenum, path) in enumerate(annotated):
        if (hsh, path) not in fctxmap:
            fctxmap[(hsh, path)] = _lazyfctx(repo, hsh, path)
        # linenum: the user wants 1-based, we have 0-based.
        lineno = linenum + 1
        fctx = fctxmap[(hsh, path)]
        line = contents[i]
        results.append(annotateline(fctx=fctx, lineno=lineno, text=line))
    return results

def _getmaster(fctx):
    """(fctx) -> str"""
    return fctx._repo.ui.config('fastannotate', 'mainbranch') or 'default'

def _doannotate(fctx, follow=True, diffopts=None):
    """like the vanilla fctx.annotate, but do it via fastannotate, and make
    the output format compatible with the vanilla fctx.annotate.
    may raise Exception, and always return line numbers.
    """
    master = _getmaster(fctx)
    annotated = contents = None

    with context.fctxannotatecontext(fctx, follow, diffopts) as ac:
        try:
            annotated, contents = ac.annotate(fctx.rev(), master=master,
                                              showpath=True, showlines=True)
        except Exception:
            ac.rebuild() # try rebuild once
            fctx._repo.ui.debug('fastannotate: %s: rebuilding broken cache\n'
                                % fctx._path)
            try:
                annotated, contents = ac.annotate(fctx.rev(), master=master,
                                                  showpath=True, showlines=True)
            except Exception:
                raise

    assert annotated and contents
    return _convertoutputs(fctx._repo, annotated, contents)

def _hgwebannotate(orig, fctx, ui):
    diffopts = patch.difffeatureopts(ui, untrusted=True,
                                     section='annotate', whitespace=True)
    return _doannotate(fctx, diffopts=diffopts)

def _fctxannotate(orig, self, follow=False, linenumber=False, skiprevs=None,
                  diffopts=None):
    if skiprevs:
        # skiprevs is not supported yet
        return orig(self, follow, linenumber, skiprevs=skiprevs,
                    diffopts=diffopts)
    try:
        return _doannotate(self, follow, diffopts)
    except Exception as ex:
        self._repo.ui.debug('fastannotate: falling back to the vanilla '
                            'annotate: %r\n' % ex)
        return orig(self, follow=follow, skiprevs=skiprevs,
                    diffopts=diffopts)

def _remotefctxannotate(orig, self, follow=False, skiprevs=None, diffopts=None):
    # skipset: a set-like used to test if a fctx needs to be downloaded
    with context.fctxannotatecontext(self, follow, diffopts) as ac:
        skipset = revmap.revmap(ac.revmappath)
    return orig(self, follow, skiprevs=skiprevs, diffopts=diffopts,
                prefetchskip=skipset)

def replacehgwebannotate():
    extensions.wrapfunction(hgweb.webutil, 'annotate', _hgwebannotate)

def replacefctxannotate():
    extensions.wrapfunction(hgcontext.basefilectx, 'annotate', _fctxannotate)