view mercurial/templatefuncs.py @ 37557:734515aca84d

wireproto: define and implement HTTP handshake to upgrade protocol

When clients connect to repositories over HTTP, they issue a request
to the well-known URL "?cmd=capabilities" to fetch the repository
capabilities. This is the handshake portion of the HTTP protocol.

This commit defines a mechanism to use that HTTP request to return
information about modern server features.

If a client sends an X-HgUpgrade-* header containing a list of
client-supported API names, the server responds with a response
containing information about available services. This includes
the normal capabilities string. So if the server doesn't support
any newer services, the client can easily fall back.

By advertising supported services from clients, server operators
can see and log what client support exists in the wild. This will
also help with debugging.

The response contains the base path to API services. We know there
are potential issues with the <repo>/api/ URL space conflicting with
hgwebdir and subrepos. By making the API URL dynamic from the
perspective of the client, the URL for APIs is not subject to backwards
compatibility concerns - at least as long as a ?cmd=capabilities request
is made.

We've also defined the ``cbor`` client capability for the X-HgProto-*
header. This MUST be sent in order to get the modern response from
"?cmd=capabilities". During implementation, I initially always sent
an application/mercurial-cbor response. However, the handshake
mechanism will be more future compatible if the client is in charge
of which formats to request. We already perform content negotiation
from X-HgProto-*, so keying off this for the capabilities response
feels appropriate.

In addition, I initially used application/cbor. However, it is
conceivable that a non-Mercurial server could serve application/cbor.
To rule out this possibility, I've invented a new media type that
is Mercurial specific and can't be confused for generic CBOR.

Differential Revision: https://phab.mercurial-scm.org/D3242

# templatefuncs.py - common template functions
#
# Copyright 2005, 2006 Matt Mackall <[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.

from __future__ import absolute_import

import re

from .i18n import _
from . import (
    color,
    encoding,
    error,
    minirst,
    obsutil,
    pycompat,
    registrar,
    revset as revsetmod,
    revsetlang,
    scmutil,
    templatefilters,
    templatekw,
    templateutil,
    util,
)
from .utils import (
    dateutil,
    stringutil,
)

evalrawexp = templateutil.evalrawexp
evalfuncarg = templateutil.evalfuncarg
evalboolean = templateutil.evalboolean
evaldate = templateutil.evaldate
evalinteger = templateutil.evalinteger
evalstring = templateutil.evalstring
evalstringliteral = templateutil.evalstringliteral

# dict of template built-in functions
funcs = {}
templatefunc = registrar.templatefunc(funcs)

@templatefunc('date(date[, fmt])')
def date(context, mapping, args):
    """Format a date. See :hg:`help dates` for formatting
    strings. The default is a Unix date format, including the timezone:
    "Mon Sep 04 15:13:13 2006 0700"."""
    if not (1 <= len(args) <= 2):
        # i18n: "date" is a keyword
        raise error.ParseError(_("date expects one or two arguments"))

    date = evaldate(context, mapping, args[0],
                    # i18n: "date" is a keyword
                    _("date expects a date information"))
    fmt = None
    if len(args) == 2:
        fmt = evalstring(context, mapping, args[1])
    if fmt is None:
        return dateutil.datestr(date)
    else:
        return dateutil.datestr(date, fmt)

@templatefunc('dict([[key=]value...])', argspec='*args **kwargs')
def dict_(context, mapping, args):
    """Construct a dict from key-value pairs. A key may be omitted if
    a value expression can provide an unambiguous name."""
    data = util.sortdict()

    for v in args['args']:
        k = templateutil.findsymbolicname(v)
        if not k:
            raise error.ParseError(_('dict key cannot be inferred'))
        if k in data or k in args['kwargs']:
            raise error.ParseError(_("duplicated dict key '%s' inferred") % k)
        data[k] = evalfuncarg(context, mapping, v)

    data.update((k, evalfuncarg(context, mapping, v))
                for k, v in args['kwargs'].iteritems())
    return templateutil.hybriddict(data)

@templatefunc('diff([includepattern [, excludepattern]])')
def diff(context, mapping, args):
    """Show a diff, optionally
    specifying files to include or exclude."""
    if len(args) > 2:
        # i18n: "diff" is a keyword
        raise error.ParseError(_("diff expects zero, one, or two arguments"))

    def getpatterns(i):
        if i < len(args):
            s = evalstring(context, mapping, args[i]).strip()
            if s:
                return [s]
        return []

    ctx = context.resource(mapping, 'ctx')
    chunks = ctx.diff(match=ctx.match([], getpatterns(0), getpatterns(1)))

    return ''.join(chunks)

@templatefunc('extdata(source)', argspec='source')
def extdata(context, mapping, args):
    """Show a text read from the specified extdata source. (EXPERIMENTAL)"""
    if 'source' not in args:
        # i18n: "extdata" is a keyword
        raise error.ParseError(_('extdata expects one argument'))

    source = evalstring(context, mapping, args['source'])
    cache = context.resource(mapping, 'cache').setdefault('extdata', {})
    ctx = context.resource(mapping, 'ctx')
    if source in cache:
        data = cache[source]
    else:
        data = cache[source] = scmutil.extdatasource(ctx.repo(), source)
    return data.get(ctx.rev(), '')

@templatefunc('files(pattern)')
def files(context, mapping, args):
    """All files of the current changeset matching the pattern. See
    :hg:`help patterns`."""
    if not len(args) == 1:
        # i18n: "files" is a keyword
        raise error.ParseError(_("files expects one argument"))

    raw = evalstring(context, mapping, args[0])
    ctx = context.resource(mapping, 'ctx')
    m = ctx.match([raw])
    files = list(ctx.matches(m))
    return templateutil.compatlist(context, mapping, "file", files)

@templatefunc('fill(text[, width[, initialident[, hangindent]]])')
def fill(context, mapping, args):
    """Fill many
    paragraphs with optional indentation. See the "fill" filter."""
    if not (1 <= len(args) <= 4):
        # i18n: "fill" is a keyword
        raise error.ParseError(_("fill expects one to four arguments"))

    text = evalstring(context, mapping, args[0])
    width = 76
    initindent = ''
    hangindent = ''
    if 2 <= len(args) <= 4:
        width = evalinteger(context, mapping, args[1],
                            # i18n: "fill" is a keyword
                            _("fill expects an integer width"))
        try:
            initindent = evalstring(context, mapping, args[2])
            hangindent = evalstring(context, mapping, args[3])
        except IndexError:
            pass

    return templatefilters.fill(text, width, initindent, hangindent)

@templatefunc('formatnode(node)')
def formatnode(context, mapping, args):
    """Obtain the preferred form of a changeset hash. (DEPRECATED)"""
    if len(args) != 1:
        # i18n: "formatnode" is a keyword
        raise error.ParseError(_("formatnode expects one argument"))

    ui = context.resource(mapping, 'ui')
    node = evalstring(context, mapping, args[0])
    if ui.debugflag:
        return node
    return templatefilters.short(node)

@templatefunc('mailmap(author)')
def mailmap(context, mapping, args):
    """Return the author, updated according to the value
    set in the .mailmap file"""
    if len(args) != 1:
        raise error.ParseError(_("mailmap expects one argument"))

    author = evalstring(context, mapping, args[0])

    cache = context.resource(mapping, 'cache')
    repo = context.resource(mapping, 'repo')

    if 'mailmap' not in cache:
        data = repo.wvfs.tryread('.mailmap')
        cache['mailmap'] = stringutil.parsemailmap(data)

    return stringutil.mapname(cache['mailmap'], author)

@templatefunc('pad(text, width[, fillchar=\' \'[, left=False]])',
              argspec='text width fillchar left')
def pad(context, mapping, args):
    """Pad text with a
    fill character."""
    if 'text' not in args or 'width' not in args:
        # i18n: "pad" is a keyword
        raise error.ParseError(_("pad() expects two to four arguments"))

    width = evalinteger(context, mapping, args['width'],
                        # i18n: "pad" is a keyword
                        _("pad() expects an integer width"))

    text = evalstring(context, mapping, args['text'])

    left = False
    fillchar = ' '
    if 'fillchar' in args:
        fillchar = evalstring(context, mapping, args['fillchar'])
        if len(color.stripeffects(fillchar)) != 1:
            # i18n: "pad" is a keyword
            raise error.ParseError(_("pad() expects a single fill character"))
    if 'left' in args:
        left = evalboolean(context, mapping, args['left'])

    fillwidth = width - encoding.colwidth(color.stripeffects(text))
    if fillwidth <= 0:
        return text
    if left:
        return fillchar * fillwidth + text
    else:
        return text + fillchar * fillwidth

@templatefunc('indent(text, indentchars[, firstline])')
def indent(context, mapping, args):
    """Indents all non-empty lines
    with the characters given in the indentchars string. An optional
    third parameter will override the indent for the first line only
    if present."""
    if not (2 <= len(args) <= 3):
        # i18n: "indent" is a keyword
        raise error.ParseError(_("indent() expects two or three arguments"))

    text = evalstring(context, mapping, args[0])
    indent = evalstring(context, mapping, args[1])

    if len(args) == 3:
        firstline = evalstring(context, mapping, args[2])
    else:
        firstline = indent

    # the indent function doesn't indent the first line, so we do it here
    return templatefilters.indent(firstline + text, indent)

@templatefunc('get(dict, key)')
def get(context, mapping, args):
    """Get an attribute/key from an object. Some keywords
    are complex types. This function allows you to obtain the value of an
    attribute on these types."""
    if len(args) != 2:
        # i18n: "get" is a keyword
        raise error.ParseError(_("get() expects two arguments"))

    dictarg = evalfuncarg(context, mapping, args[0])
    if not util.safehasattr(dictarg, 'get'):
        # i18n: "get" is a keyword
        raise error.ParseError(_("get() expects a dict as first argument"))

    key = evalfuncarg(context, mapping, args[1])
    return templateutil.getdictitem(dictarg, key)

@templatefunc('if(expr, then[, else])')
def if_(context, mapping, args):
    """Conditionally execute based on the result of
    an expression."""
    if not (2 <= len(args) <= 3):
        # i18n: "if" is a keyword
        raise error.ParseError(_("if expects two or three arguments"))

    test = evalboolean(context, mapping, args[0])
    if test:
        return evalrawexp(context, mapping, args[1])
    elif len(args) == 3:
        return evalrawexp(context, mapping, args[2])

@templatefunc('ifcontains(needle, haystack, then[, else])')
def ifcontains(context, mapping, args):
    """Conditionally execute based
    on whether the item "needle" is in "haystack"."""
    if not (3 <= len(args) <= 4):
        # i18n: "ifcontains" is a keyword
        raise error.ParseError(_("ifcontains expects three or four arguments"))

    haystack = evalfuncarg(context, mapping, args[1])
    keytype = getattr(haystack, 'keytype', None)
    try:
        needle = evalrawexp(context, mapping, args[0])
        needle = templateutil.unwrapastype(context, mapping, needle,
                                           keytype or bytes)
        found = (needle in haystack)
    except error.ParseError:
        found = False

    if found:
        return evalrawexp(context, mapping, args[2])
    elif len(args) == 4:
        return evalrawexp(context, mapping, args[3])

@templatefunc('ifeq(expr1, expr2, then[, else])')
def ifeq(context, mapping, args):
    """Conditionally execute based on
    whether 2 items are equivalent."""
    if not (3 <= len(args) <= 4):
        # i18n: "ifeq" is a keyword
        raise error.ParseError(_("ifeq expects three or four arguments"))

    test = evalstring(context, mapping, args[0])
    match = evalstring(context, mapping, args[1])
    if test == match:
        return evalrawexp(context, mapping, args[2])
    elif len(args) == 4:
        return evalrawexp(context, mapping, args[3])

@templatefunc('join(list, sep)')
def join(context, mapping, args):
    """Join items in a list with a delimiter."""
    if not (1 <= len(args) <= 2):
        # i18n: "join" is a keyword
        raise error.ParseError(_("join expects one or two arguments"))

    joinset = evalrawexp(context, mapping, args[0])
    joiner = " "
    if len(args) > 1:
        joiner = evalstring(context, mapping, args[1])
    if isinstance(joinset, templateutil.wrapped):
        return joinset.join(context, mapping, joiner)
    # TODO: perhaps a generator should be stringify()-ed here, but we can't
    # because hgweb abuses it as a keyword that returns a list of dicts.
    joinset = templateutil.unwrapvalue(context, mapping, joinset)
    return templateutil.joinitems(pycompat.maybebytestr(joinset), joiner)

@templatefunc('label(label, expr)')
def label(context, mapping, args):
    """Apply a label to generated content. Content with
    a label applied can result in additional post-processing, such as
    automatic colorization."""
    if len(args) != 2:
        # i18n: "label" is a keyword
        raise error.ParseError(_("label expects two arguments"))

    ui = context.resource(mapping, 'ui')
    thing = evalstring(context, mapping, args[1])
    # preserve unknown symbol as literal so effects like 'red', 'bold',
    # etc. don't need to be quoted
    label = evalstringliteral(context, mapping, args[0])

    return ui.label(thing, label)

@templatefunc('latesttag([pattern])')
def latesttag(context, mapping, args):
    """The global tags matching the given pattern on the
    most recent globally tagged ancestor of this changeset.
    If no such tags exist, the "{tag}" template resolves to
    the string "null"."""
    if len(args) > 1:
        # i18n: "latesttag" is a keyword
        raise error.ParseError(_("latesttag expects at most one argument"))

    pattern = None
    if len(args) == 1:
        pattern = evalstring(context, mapping, args[0])
    return templatekw.showlatesttags(context, mapping, pattern)

@templatefunc('localdate(date[, tz])')
def localdate(context, mapping, args):
    """Converts a date to the specified timezone.
    The default is local date."""
    if not (1 <= len(args) <= 2):
        # i18n: "localdate" is a keyword
        raise error.ParseError(_("localdate expects one or two arguments"))

    date = evaldate(context, mapping, args[0],
                    # i18n: "localdate" is a keyword
                    _("localdate expects a date information"))
    if len(args) >= 2:
        tzoffset = None
        tz = evalfuncarg(context, mapping, args[1])
        if isinstance(tz, bytes):
            tzoffset, remainder = dateutil.parsetimezone(tz)
            if remainder:
                tzoffset = None
        if tzoffset is None:
            try:
                tzoffset = int(tz)
            except (TypeError, ValueError):
                # i18n: "localdate" is a keyword
                raise error.ParseError(_("localdate expects a timezone"))
    else:
        tzoffset = dateutil.makedate()[1]
    return (date[0], tzoffset)

@templatefunc('max(iterable)')
def max_(context, mapping, args, **kwargs):
    """Return the max of an iterable"""
    if len(args) != 1:
        # i18n: "max" is a keyword
        raise error.ParseError(_("max expects one argument"))

    iterable = evalfuncarg(context, mapping, args[0])
    try:
        x = max(pycompat.maybebytestr(iterable))
    except (TypeError, ValueError):
        # i18n: "max" is a keyword
        raise error.ParseError(_("max first argument should be an iterable"))
    return templateutil.wraphybridvalue(iterable, x, x)

@templatefunc('min(iterable)')
def min_(context, mapping, args, **kwargs):
    """Return the min of an iterable"""
    if len(args) != 1:
        # i18n: "min" is a keyword
        raise error.ParseError(_("min expects one argument"))

    iterable = evalfuncarg(context, mapping, args[0])
    try:
        x = min(pycompat.maybebytestr(iterable))
    except (TypeError, ValueError):
        # i18n: "min" is a keyword
        raise error.ParseError(_("min first argument should be an iterable"))
    return templateutil.wraphybridvalue(iterable, x, x)

@templatefunc('mod(a, b)')
def mod(context, mapping, args):
    """Calculate a mod b such that a / b + a mod b == a"""
    if not len(args) == 2:
        # i18n: "mod" is a keyword
        raise error.ParseError(_("mod expects two arguments"))

    func = lambda a, b: a % b
    return templateutil.runarithmetic(context, mapping,
                                      (func, args[0], args[1]))

@templatefunc('obsfateoperations(markers)')
def obsfateoperations(context, mapping, args):
    """Compute obsfate related information based on markers (EXPERIMENTAL)"""
    if len(args) != 1:
        # i18n: "obsfateoperations" is a keyword
        raise error.ParseError(_("obsfateoperations expects one argument"))

    markers = evalfuncarg(context, mapping, args[0])

    try:
        data = obsutil.markersoperations(markers)
        return templateutil.hybridlist(data, name='operation')
    except (TypeError, KeyError):
        # i18n: "obsfateoperations" is a keyword
        errmsg = _("obsfateoperations first argument should be an iterable")
        raise error.ParseError(errmsg)

@templatefunc('obsfatedate(markers)')
def obsfatedate(context, mapping, args):
    """Compute obsfate related information based on markers (EXPERIMENTAL)"""
    if len(args) != 1:
        # i18n: "obsfatedate" is a keyword
        raise error.ParseError(_("obsfatedate expects one argument"))

    markers = evalfuncarg(context, mapping, args[0])

    try:
        data = obsutil.markersdates(markers)
        return templateutil.hybridlist(data, name='date', fmt='%d %d')
    except (TypeError, KeyError):
        # i18n: "obsfatedate" is a keyword
        errmsg = _("obsfatedate first argument should be an iterable")
        raise error.ParseError(errmsg)

@templatefunc('obsfateusers(markers)')
def obsfateusers(context, mapping, args):
    """Compute obsfate related information based on markers (EXPERIMENTAL)"""
    if len(args) != 1:
        # i18n: "obsfateusers" is a keyword
        raise error.ParseError(_("obsfateusers expects one argument"))

    markers = evalfuncarg(context, mapping, args[0])

    try:
        data = obsutil.markersusers(markers)
        return templateutil.hybridlist(data, name='user')
    except (TypeError, KeyError, ValueError):
        # i18n: "obsfateusers" is a keyword
        msg = _("obsfateusers first argument should be an iterable of "
                "obsmakers")
        raise error.ParseError(msg)

@templatefunc('obsfateverb(successors, markers)')
def obsfateverb(context, mapping, args):
    """Compute obsfate related information based on successors (EXPERIMENTAL)"""
    if len(args) != 2:
        # i18n: "obsfateverb" is a keyword
        raise error.ParseError(_("obsfateverb expects two arguments"))

    successors = evalfuncarg(context, mapping, args[0])
    markers = evalfuncarg(context, mapping, args[1])

    try:
        return obsutil.obsfateverb(successors, markers)
    except TypeError:
        # i18n: "obsfateverb" is a keyword
        errmsg = _("obsfateverb first argument should be countable")
        raise error.ParseError(errmsg)

@templatefunc('relpath(path)')
def relpath(context, mapping, args):
    """Convert a repository-absolute path into a filesystem path relative to
    the current working directory."""
    if len(args) != 1:
        # i18n: "relpath" is a keyword
        raise error.ParseError(_("relpath expects one argument"))

    repo = context.resource(mapping, 'ctx').repo()
    path = evalstring(context, mapping, args[0])
    return repo.pathto(path)

@templatefunc('revset(query[, formatargs...])')
def revset(context, mapping, args):
    """Execute a revision set query. See
    :hg:`help revset`."""
    if not len(args) > 0:
        # i18n: "revset" is a keyword
        raise error.ParseError(_("revset expects one or more arguments"))

    raw = evalstring(context, mapping, args[0])
    ctx = context.resource(mapping, 'ctx')
    repo = ctx.repo()

    def query(expr):
        m = revsetmod.match(repo.ui, expr, repo=repo)
        return m(repo)

    if len(args) > 1:
        formatargs = [evalfuncarg(context, mapping, a) for a in args[1:]]
        revs = query(revsetlang.formatspec(raw, *formatargs))
        revs = list(revs)
    else:
        cache = context.resource(mapping, 'cache')
        revsetcache = cache.setdefault("revsetcache", {})
        if raw in revsetcache:
            revs = revsetcache[raw]
        else:
            revs = query(raw)
            revs = list(revs)
            revsetcache[raw] = revs
    return templatekw.showrevslist(context, mapping, "revision", revs)

@templatefunc('rstdoc(text, style)')
def rstdoc(context, mapping, args):
    """Format reStructuredText."""
    if len(args) != 2:
        # i18n: "rstdoc" is a keyword
        raise error.ParseError(_("rstdoc expects two arguments"))

    text = evalstring(context, mapping, args[0])
    style = evalstring(context, mapping, args[1])

    return minirst.format(text, style=style, keep=['verbose'])

@templatefunc('separate(sep, args)', argspec='sep *args')
def separate(context, mapping, args):
    """Add a separator between non-empty arguments."""
    if 'sep' not in args:
        # i18n: "separate" is a keyword
        raise error.ParseError(_("separate expects at least one argument"))

    sep = evalstring(context, mapping, args['sep'])
    first = True
    for arg in args['args']:
        argstr = evalstring(context, mapping, arg)
        if not argstr:
            continue
        if first:
            first = False
        else:
            yield sep
        yield argstr

@templatefunc('shortest(node, minlength=4)')
def shortest(context, mapping, args):
    """Obtain the shortest representation of
    a node."""
    if not (1 <= len(args) <= 2):
        # i18n: "shortest" is a keyword
        raise error.ParseError(_("shortest() expects one or two arguments"))

    node = evalstring(context, mapping, args[0])

    minlength = 4
    if len(args) > 1:
        minlength = evalinteger(context, mapping, args[1],
                                # i18n: "shortest" is a keyword
                                _("shortest() expects an integer minlength"))

    # _partialmatch() of filtered changelog could take O(len(repo)) time,
    # which would be unacceptably slow. so we look for hash collision in
    # unfiltered space, which means some hashes may be slightly longer.
    cl = context.resource(mapping, 'ctx')._repo.unfiltered().changelog
    return cl.shortest(node, minlength)

@templatefunc('strip(text[, chars])')
def strip(context, mapping, args):
    """Strip characters from a string. By default,
    strips all leading and trailing whitespace."""
    if not (1 <= len(args) <= 2):
        # i18n: "strip" is a keyword
        raise error.ParseError(_("strip expects one or two arguments"))

    text = evalstring(context, mapping, args[0])
    if len(args) == 2:
        chars = evalstring(context, mapping, args[1])
        return text.strip(chars)
    return text.strip()

@templatefunc('sub(pattern, replacement, expression)')
def sub(context, mapping, args):
    """Perform text substitution
    using regular expressions."""
    if len(args) != 3:
        # i18n: "sub" is a keyword
        raise error.ParseError(_("sub expects three arguments"))

    pat = evalstring(context, mapping, args[0])
    rpl = evalstring(context, mapping, args[1])
    src = evalstring(context, mapping, args[2])
    try:
        patre = re.compile(pat)
    except re.error:
        # i18n: "sub" is a keyword
        raise error.ParseError(_("sub got an invalid pattern: %s") % pat)
    try:
        yield patre.sub(rpl, src)
    except re.error:
        # i18n: "sub" is a keyword
        raise error.ParseError(_("sub got an invalid replacement: %s") % rpl)

@templatefunc('startswith(pattern, text)')
def startswith(context, mapping, args):
    """Returns the value from the "text" argument
    if it begins with the content from the "pattern" argument."""
    if len(args) != 2:
        # i18n: "startswith" is a keyword
        raise error.ParseError(_("startswith expects two arguments"))

    patn = evalstring(context, mapping, args[0])
    text = evalstring(context, mapping, args[1])
    if text.startswith(patn):
        return text
    return ''

@templatefunc('word(number, text[, separator])')
def word(context, mapping, args):
    """Return the nth word from a string."""
    if not (2 <= len(args) <= 3):
        # i18n: "word" is a keyword
        raise error.ParseError(_("word expects two or three arguments, got %d")
                               % len(args))

    num = evalinteger(context, mapping, args[0],
                      # i18n: "word" is a keyword
                      _("word expects an integer index"))
    text = evalstring(context, mapping, args[1])
    if len(args) == 3:
        splitter = evalstring(context, mapping, args[2])
    else:
        splitter = None

    tokens = text.split(splitter)
    if num >= len(tokens) or num < -len(tokens):
        return ''
    else:
        return tokens[num]

def loadfunction(ui, extname, registrarobj):
    """Load template function from specified registrarobj
    """
    for name, func in registrarobj._table.iteritems():
        funcs[name] = func

# tell hggettext to extract docstrings from these functions:
i18nfunctions = funcs.values()