view mercurial/templatefilters.py @ 37051:40206e227412

wireproto: define and implement protocol for issuing requests

The existing HTTP and SSH wire protocols suffer from a host of flaws
and shortcomings. I've been wanting to rewrite the protocol for a while
now. Supporting partial clone - which will require new wire protocol
commands and capabilities - and other advanced server functionality
will be much easier if we start from a clean slate and don't have
to be constrained by limitations of the existing wire protocol.

This commit starts to introduce a new data exchange format for
use over the wire protocol.

The new protocol is built on top of "frames," which are atomic
units of metadata + data. Frames will make it easier to implement
proxies and other mechanisms that want to inspect data without
having to maintain state. The existing frame metadata is very
minimal and it will evolve heavily. (We will eventually support
things like concurrent requests, out-of-order responses,
compression, side-channels for status updates, etc. Some of
these will require additions to the frame header.)

Another benefit of frames is that all reads are of a fixed size.
A reader works by consuming a frame header, extracting the payload
length, then reading that many bytes. No lookahead, buffering, or
memory reallocations are needed.

The new protocol attempts to be transport agnostic. I want all that's
required to use the new protocol to be a pair of unidirectional,
half-duplex pipes. (Yes, we will eventually make use of full-duplex
pipes, but that's for another commit.) Notably, when the SSH
transport switches to this new protocol, stderr will be unused.
This is by design: the lack of stderr on HTTP harms protocol
behavior there. By shoehorning everything into a pair of pipes,
we can have more consistent behavior across transports.

We currently only define the client side parts of the new protocol,
specifically the bits for requesting that a command run. This keeps
the new code and feature small and somewhat easy to review.

We add support to `hg debugwireproto` for writing frames into
HTTP request bodies. Our tests that issue commands to the new
HTTP endpoint have been updated to transmit frames. The server
bits haven't been touched to consume the frames yet. This will
occur in the next commit...

Astute readers may notice that the command name is transmitted in
both the HTTP request URL and the command request frame. This is
partially a kludge from me initially implementing the frame-based
protocol for SSH first. But it is also a feature: I intend to
eventually support issuing multiple commands per HTTP request. This
will allow us to replace the abomination that is the "batch" wire
protocol command with a protocol-level mechanism for performing
multi-dispatch. Because I want the frame-based protocol to be
as similar as possible across transports, I'd rather we (redundantly)
include the command name in the frame than differ behavior between
transports that have out-of-band routing information (like HTTP)
readily available.

Differential Revision: https://phab.mercurial-scm.org/D2851

# templatefilters.py - common template expansion filters
#
# Copyright 2005-2008 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 os
import re
import time

from . import (
    encoding,
    error,
    node,
    pycompat,
    registrar,
    templateutil,
    url,
    util,
)
from .utils import dateutil

urlerr = util.urlerr
urlreq = util.urlreq

if pycompat.ispy3:
    long = int

# filters are callables like:
#   fn(obj)
# with:
#   obj - object to be filtered (text, date, list and so on)
filters = {}

templatefilter = registrar.templatefilter(filters)

@templatefilter('addbreaks')
def addbreaks(text):
    """Any text. Add an XHTML "<br />" tag before the end of
    every line except the last.
    """
    return text.replace('\n', '<br/>\n')

agescales = [("year", 3600 * 24 * 365, 'Y'),
             ("month", 3600 * 24 * 30, 'M'),
             ("week", 3600 * 24 * 7, 'W'),
             ("day", 3600 * 24, 'd'),
             ("hour", 3600, 'h'),
             ("minute", 60, 'm'),
             ("second", 1, 's')]

@templatefilter('age')
def age(date, abbrev=False):
    """Date. Returns a human-readable date/time difference between the
    given date/time and the current date/time.
    """

    def plural(t, c):
        if c == 1:
            return t
        return t + "s"
    def fmt(t, c, a):
        if abbrev:
            return "%d%s" % (c, a)
        return "%d %s" % (c, plural(t, c))

    now = time.time()
    then = date[0]
    future = False
    if then > now:
        future = True
        delta = max(1, int(then - now))
        if delta > agescales[0][1] * 30:
            return 'in the distant future'
    else:
        delta = max(1, int(now - then))
        if delta > agescales[0][1] * 2:
            return dateutil.shortdate(date)

    for t, s, a in agescales:
        n = delta // s
        if n >= 2 or s == 1:
            if future:
                return '%s from now' % fmt(t, n, a)
            return '%s ago' % fmt(t, n, a)

@templatefilter('basename')
def basename(path):
    """Any text. Treats the text as a path, and returns the last
    component of the path after splitting by the path separator.
    For example, "foo/bar/baz" becomes "baz" and "foo/bar//" becomes "".
    """
    return os.path.basename(path)

@templatefilter('count')
def count(i):
    """List or text. Returns the length as an integer."""
    return len(i)

@templatefilter('dirname')
def dirname(path):
    """Any text. Treats the text as a path, and strips the last
    component of the path after splitting by the path separator.
    """
    return os.path.dirname(path)

@templatefilter('domain')
def domain(author):
    """Any text. Finds the first string that looks like an email
    address, and extracts just the domain component. Example: ``User
    <[e-mail]>`` becomes ``example.com``.
    """
    f = author.find('@')
    if f == -1:
        return ''
    author = author[f + 1:]
    f = author.find('>')
    if f >= 0:
        author = author[:f]
    return author

@templatefilter('email')
def email(text):
    """Any text. Extracts the first string that looks like an email
    address. Example: ``User <[e-mail]>`` becomes
    ``[e-mail]``.
    """
    return util.email(text)

@templatefilter('escape')
def escape(text):
    """Any text. Replaces the special XML/XHTML characters "&", "<"
    and ">" with XML entities, and filters out NUL characters.
    """
    return url.escape(text.replace('\0', ''), True)

para_re = None
space_re = None

def fill(text, width, initindent='', hangindent=''):
    '''fill many paragraphs with optional indentation.'''
    global para_re, space_re
    if para_re is None:
        para_re = re.compile('(\n\n|\n\\s*[-*]\\s*)', re.M)
        space_re = re.compile(br'  +')

    def findparas():
        start = 0
        while True:
            m = para_re.search(text, start)
            if not m:
                uctext = encoding.unifromlocal(text[start:])
                w = len(uctext)
                while 0 < w and uctext[w - 1].isspace():
                    w -= 1
                yield (encoding.unitolocal(uctext[:w]),
                       encoding.unitolocal(uctext[w:]))
                break
            yield text[start:m.start(0)], m.group(1)
            start = m.end(1)

    return "".join([util.wrap(space_re.sub(' ', util.wrap(para, width)),
                              width, initindent, hangindent) + rest
                    for para, rest in findparas()])

@templatefilter('fill68')
def fill68(text):
    """Any text. Wraps the text to fit in 68 columns."""
    return fill(text, 68)

@templatefilter('fill76')
def fill76(text):
    """Any text. Wraps the text to fit in 76 columns."""
    return fill(text, 76)

@templatefilter('firstline')
def firstline(text):
    """Any text. Returns the first line of text."""
    try:
        return text.splitlines(True)[0].rstrip('\r\n')
    except IndexError:
        return ''

@templatefilter('hex')
def hexfilter(text):
    """Any text. Convert a binary Mercurial node identifier into
    its long hexadecimal representation.
    """
    return node.hex(text)

@templatefilter('hgdate')
def hgdate(text):
    """Date. Returns the date as a pair of numbers: "1157407993
    25200" (Unix timestamp, timezone offset).
    """
    return "%d %d" % text

@templatefilter('isodate')
def isodate(text):
    """Date. Returns the date in ISO 8601 format: "2009-08-18 13:00
    +0200".
    """
    return dateutil.datestr(text, '%Y-%m-%d %H:%M %1%2')

@templatefilter('isodatesec')
def isodatesec(text):
    """Date. Returns the date in ISO 8601 format, including
    seconds: "2009-08-18 13:00:13 +0200". See also the rfc3339date
    filter.
    """
    return dateutil.datestr(text, '%Y-%m-%d %H:%M:%S %1%2')

def indent(text, prefix):
    '''indent each non-empty line of text after first with prefix.'''
    lines = text.splitlines()
    num_lines = len(lines)
    endswithnewline = text[-1:] == '\n'
    def indenter():
        for i in xrange(num_lines):
            l = lines[i]
            if i and l.strip():
                yield prefix
            yield l
            if i < num_lines - 1 or endswithnewline:
                yield '\n'
    return "".join(indenter())

@templatefilter('json')
def json(obj, paranoid=True):
    if obj is None:
        return 'null'
    elif obj is False:
        return 'false'
    elif obj is True:
        return 'true'
    elif isinstance(obj, (int, long, float)):
        return pycompat.bytestr(obj)
    elif isinstance(obj, bytes):
        return '"%s"' % encoding.jsonescape(obj, paranoid=paranoid)
    elif isinstance(obj, str):
        # This branch is unreachable on Python 2, because bytes == str
        # and we'll return in the next-earlier block in the elif
        # ladder. On Python 3, this helps us catch bugs before they
        # hurt someone.
        raise error.ProgrammingError(
            'Mercurial only does output with bytes on Python 3: %r' % obj)
    elif util.safehasattr(obj, 'keys'):
        out = ['"%s": %s' % (encoding.jsonescape(k, paranoid=paranoid),
                             json(v, paranoid))
               for k, v in sorted(obj.iteritems())]
        return '{' + ', '.join(out) + '}'
    elif util.safehasattr(obj, '__iter__'):
        out = [json(i, paranoid) for i in obj]
        return '[' + ', '.join(out) + ']'
    else:
        raise TypeError('cannot encode type %s' % obj.__class__.__name__)

@templatefilter('lower')
def lower(text):
    """Any text. Converts the text to lowercase."""
    return encoding.lower(text)

@templatefilter('nonempty')
def nonempty(text):
    """Any text. Returns '(none)' if the string is empty."""
    return text or "(none)"

@templatefilter('obfuscate')
def obfuscate(text):
    """Any text. Returns the input text rendered as a sequence of
    XML entities.
    """
    text = unicode(text, pycompat.sysstr(encoding.encoding), r'replace')
    return ''.join(['&#%d;' % ord(c) for c in text])

@templatefilter('permissions')
def permissions(flags):
    if "l" in flags:
        return "lrwxrwxrwx"
    if "x" in flags:
        return "-rwxr-xr-x"
    return "-rw-r--r--"

@templatefilter('person')
def person(author):
    """Any text. Returns the name before an email address,
    interpreting it as per RFC 5322.

    >>> person(b'foo@bar')
    'foo'
    >>> person(b'Foo Bar <foo@bar>')
    'Foo Bar'
    >>> person(b'"Foo Bar" <foo@bar>')
    'Foo Bar'
    >>> person(b'"Foo \"buz\" Bar" <foo@bar>')
    'Foo "buz" Bar'
    >>> # The following are invalid, but do exist in real-life
    ...
    >>> person(b'Foo "buz" Bar <foo@bar>')
    'Foo "buz" Bar'
    >>> person(b'"Foo Bar <foo@bar>')
    'Foo Bar'
    """
    if '@' not in author:
        return author
    f = author.find('<')
    if f != -1:
        return author[:f].strip(' "').replace('\\"', '"')
    f = author.find('@')
    return author[:f].replace('.', ' ')

@templatefilter('revescape')
def revescape(text):
    """Any text. Escapes all "special" characters, except @.
    Forward slashes are escaped twice to prevent web servers from prematurely
    unescaping them. For example, "@foo bar/baz" becomes "@foo%20bar%252Fbaz".
    """
    return urlreq.quote(text, safe='/@').replace('/', '%252F')

@templatefilter('rfc3339date')
def rfc3339date(text):
    """Date. Returns a date using the Internet date format
    specified in RFC 3339: "2009-08-18T13:00:13+02:00".
    """
    return dateutil.datestr(text, "%Y-%m-%dT%H:%M:%S%1:%2")

@templatefilter('rfc822date')
def rfc822date(text):
    """Date. Returns a date using the same format used in email
    headers: "Tue, 18 Aug 2009 13:00:13 +0200".
    """
    return dateutil.datestr(text, "%a, %d %b %Y %H:%M:%S %1%2")

@templatefilter('short')
def short(text):
    """Changeset hash. Returns the short form of a changeset hash,
    i.e. a 12 hexadecimal digit string.
    """
    return text[:12]

@templatefilter('shortbisect')
def shortbisect(label):
    """Any text. Treats `label` as a bisection status, and
    returns a single-character representing the status (G: good, B: bad,
    S: skipped, U: untested, I: ignored). Returns single space if `text`
    is not a valid bisection status.
    """
    if label:
        return label[0:1].upper()
    return ' '

@templatefilter('shortdate')
def shortdate(text):
    """Date. Returns a date like "2006-09-18"."""
    return dateutil.shortdate(text)

@templatefilter('slashpath')
def slashpath(path):
    """Any text. Replaces the native path separator with slash."""
    return util.pconvert(path)

@templatefilter('splitlines')
def splitlines(text):
    """Any text. Split text into a list of lines."""
    return templateutil.hybridlist(text.splitlines(), name='line')

@templatefilter('stringescape')
def stringescape(text):
    return util.escapestr(text)

@templatefilter('stringify')
def stringify(thing):
    """Any type. Turns the value into text by converting values into
    text and concatenating them.
    """
    return templateutil.stringify(thing)

@templatefilter('stripdir')
def stripdir(text):
    """Treat the text as path and strip a directory level, if
    possible. For example, "foo" and "foo/bar" becomes "foo".
    """
    dir = os.path.dirname(text)
    if dir == "":
        return os.path.basename(text)
    else:
        return dir

@templatefilter('tabindent')
def tabindent(text):
    """Any text. Returns the text, with every non-empty line
    except the first starting with a tab character.
    """
    return indent(text, '\t')

@templatefilter('upper')
def upper(text):
    """Any text. Converts the text to uppercase."""
    return encoding.upper(text)

@templatefilter('urlescape')
def urlescape(text):
    """Any text. Escapes all "special" characters. For example,
    "foo bar" becomes "foo%20bar".
    """
    return urlreq.quote(text)

@templatefilter('user')
def userfilter(text):
    """Any text. Returns a short representation of a user name or email
    address."""
    return util.shortuser(text)

@templatefilter('emailuser')
def emailuser(text):
    """Any text. Returns the user portion of an email address."""
    return util.emailuser(text)

@templatefilter('utf8')
def utf8(text):
    """Any text. Converts from the local character encoding to UTF-8."""
    return encoding.fromlocal(text)

@templatefilter('xmlescape')
def xmlescape(text):
    text = (text
            .replace('&', '&amp;')
            .replace('<', '&lt;')
            .replace('>', '&gt;')
            .replace('"', '&quot;')
            .replace("'", '&#39;')) # &apos; invalid in HTML
    return re.sub('[\x00-\x08\x0B\x0C\x0E-\x1F]', ' ', text)

def websub(text, websubtable):
    """:websub: Any text. Only applies to hgweb. Applies the regular
    expression replacements defined in the websub section.
    """
    if websubtable:
        for regexp, format in websubtable:
            text = regexp.sub(format, text)
    return text

def loadfilter(ui, extname, registrarobj):
    """Load template filter from specified registrarobj
    """
    for name, func in registrarobj._table.iteritems():
        filters[name] = func

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