sapling/phabstatus.py

# phabstatus.py
#
# Copyright 2015 Facebook, Inc.
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from mercurial import templatekw, extensions
from mercurial import util as hgutil
from mercurial.i18n import _

import re
import subprocess
import os
import json

def memoize(f):
    """
    NOTE: This is a hack
    if f args are like (a, b1, b2, b3) and returns [o1, o2, o3] where
    o1, o2, o3 are output of f respectively for (a, b1), (a, b2) and
    (a, b3) then we memoize f(a, b1, b2, b3)'s result but also
    f(a, b1) => o1 , f(a, b2) => o2 and f(a, b3) => o3.
    Example:

    >>> partialsum = lambda a, *b: [a + bn for bn in b]
    >>> partialsum = memoize(partialsum)

    Create a class that wraps the integer '3', otherwise we cannot add
    _phabstatuscache to it for the test
    >>> class IntWrapperClass(int):
    ...     def __new__(cls, *args, **kwargs):
    ...         return  super(IntWrapperClass, cls).__new__(cls, 3)

    >>> three = IntWrapperClass()
    >>> partialsum(three, 1, 2, 3)
    [4, 5, 6]

    As expected, we have 4 entries in the cache for a call like f(a, b, c, d)
    >>> pp(three._phabstatuscache)
    {(3, 1): [4], (3, 1, 2, 3): [4, 5, 6], (3, 2): [5], (3, 3): [6]}
    """
    def helper(*args):
        repo = args[0]
        if not hgutil.safehasattr(repo, '_phabstatuscache'):
            repo._phabstatuscache = {}
        if args not in repo._phabstatuscache:
            u = f(*args)
            repo._phabstatuscache[args] = u
            if isinstance(u, list):
                revs = args[1:]
                for x, r in enumerate(revs):
                    repo._phabstatuscache[(repo, r)] = [u[x]]
        return repo._phabstatuscache[args]
    return helper

@memoize
def getdiffstatus(repo, *diffid):
    """Perform a Conduit API call by shelling out to `arc`

    Returns status of the diff"""

    try:
        proc = subprocess.Popen(['arc', 'call-conduit', 'differential.query'],
                     stdin=subprocess.PIPE, stdout=subprocess.PIPE,
                     preexec_fn=os.setsid)
        input = json.dumps({'ids': diffid})
        repo.ui.debug("[diffrev] echo '%s' | "
                      "arc call-conduit differential.query\n" %
                      input)
        proc.stdin.write(input)
        proc.stdin.close()
        resp = proc.stdout.read()
        jsresp = json.loads(resp)
        if not jsresp:
            return 'Could not decode Conduit response'

        resp = jsresp.get('response')
        if not resp:
            error = jsresp.get('errorMessage', 'unknown error')
            repo.ui.warn("%s\n" % error)
            return ["Error"] * len(diffid)

        # This makes the code more robust in case conduit does not return
        # what we need
        result = []
        for diff in diffid:
            matchingresponse = [r for r in resp
                                  if r.get("id", None) == int(diff)]
            if not matchingresponse:
                result.append("Error")
            else:
                result.append(matchingresponse[0].get('statusName'))
        return result
    except Exception as e:
        msg = _('Could not call "arc call-conduit". No diff information can be '
                'provided.\n')
        hint = _("(Possibly disconnected operations or phabricator problems)\n")
        repo.ui.warn(msg)
        repo.ui.warn(hint)
        return ["Error"] * len(diffid)

def showphabstatus(repo, ctx, templ, **args):
    """:phabstatus: String. Return the diff approval status for a given hg rev
    """
    if hgutil.safehasattr(repo, '_smartlogrevs'):
        alldiffnumbers = [getdiffnum(repo, repo[rev])
                          for rev in repo._smartlogrevs]
        okdiffnumbers = [d for d in alldiffnumbers if d is not None]
        # To populate the cache, the result will be used by the templater
        getdiffstatus(repo, *okdiffnumbers)
        # Do this once per smartlog call, not for every revs to be displayed
        del repo._smartlogrevs

    diffnum = getdiffnum(repo, ctx)
    if diffnum is not None:
        return getdiffstatus(repo, diffnum)[0]

def getdiffnum(repo, ctx):
    descr = ctx.description()
    match = re.search('Differential Revision: https://phabricator.fb.com/(D\d+)'
                      , descr)
    revstr = match.group(1) if match else ''
    if revstr.startswith('D') and revstr[1:].isdigit():
        return revstr[1:]
    return None

def _getdag(orig, *args):
    repo = args[1]
    # We retain the smartlogrevision, this way showphabstatus knows that there
    # are multiple revisions to resolve
    repo._smartlogrevs = args[2]
    return orig(*args)

def extsetup(ui):
    templatekw.keywords['phabstatus'] = showphabstatus
    smartlog = extensions.find("smartlog")
    extensions.wrapfunction(smartlog, 'getdag', _getdag)