templatefilters: document the json filter

I don't know the exact reason why it was undocumented, but that would be
because unicode is difficult for humans. Since the json filter can now get
localstr back to UTF-8 as long as it is unprocessed (i.e. {desc|json} works,
but {desc|firstline|json} doesn't), it seems good enough to advertise the
json filter.

mercurial/templatefilters.py

@@ -1,439 +1,440 b''
 # 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 .i18n import _
 from . import (
     encoding,
     error,
     node,
     pycompat,
     registrar,
     templateutil,
     url,
     util,
 )
 from .utils import (
     dateutil,
     stringutil,
 )
 
 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', intype=bytes)
 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', intype=templateutil.date)
 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', intype=bytes)
 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."""
     try:
         return len(i)
     except TypeError:
         raise error.ParseError(_('not countable'))
 
 @templatefilter('dirname', intype=bytes)
 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', intype=bytes)
 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', intype=bytes)
 def email(text):
     """Any text. Extracts the first string that looks like an email
     address. Example: ``User <[e-mail]>`` becomes
     ``[e-mail]``.
     """
     return stringutil.email(text)
 
 @templatefilter('escape', intype=bytes)
 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([stringutil.wrap(space_re.sub(' ',
                                                  stringutil.wrap(para, width)),
                                     width, initindent, hangindent) + rest
                     for para, rest in findparas()])
 
 @templatefilter('fill68', intype=bytes)
 def fill68(text):
     """Any text. Wraps the text to fit in 68 columns."""
     return fill(text, 68)
 
 @templatefilter('fill76', intype=bytes)
 def fill76(text):
     """Any text. Wraps the text to fit in 76 columns."""
     return fill(text, 76)
 
 @templatefilter('firstline', intype=bytes)
 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', intype=bytes)
 def hexfilter(text):
     """Any text. Convert a binary Mercurial node identifier into
     its long hexadecimal representation.
     """
     return node.hex(text)
 
 @templatefilter('hgdate', intype=templateutil.date)
 def hgdate(text):
     """Date. Returns the date as a pair of numbers: "1157407993
     25200" (Unix timestamp, timezone offset).
     """
     return "%d %d" % text
 
 @templatefilter('isodate', intype=templateutil.date)
 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', intype=templateutil.date)
 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):
+    """Any object. Serializes the object to a JSON formatted text."""
     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) + ']'
     raise error.ProgrammingError('cannot encode %r' % obj)
 
 @templatefilter('lower', intype=bytes)
 def lower(text):
     """Any text. Converts the text to lowercase."""
     return encoding.lower(text)
 
 @templatefilter('nonempty', intype=bytes)
 def nonempty(text):
     """Any text. Returns '(none)' if the string is empty."""
     return text or "(none)"
 
 @templatefilter('obfuscate', intype=bytes)
 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', intype=bytes)
 def permissions(flags):
     if "l" in flags:
         return "lrwxrwxrwx"
     if "x" in flags:
         return "-rwxr-xr-x"
     return "-rw-r--r--"
 
 @templatefilter('person', intype=bytes)
 def person(author):
     """Any text. Returns the name before an email address,
     interpreting it as per RFC 5322.
     """
     return stringutil.person(author)
 
 @templatefilter('revescape', intype=bytes)
 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', intype=templateutil.date)
 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', intype=templateutil.date)
 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', intype=bytes)
 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', intype=bytes)
 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', intype=templateutil.date)
 def shortdate(text):
     """Date. Returns a date like "2006-09-18"."""
     return dateutil.shortdate(text)
 
 @templatefilter('slashpath', intype=bytes)
 def slashpath(path):
     """Any text. Replaces the native path separator with slash."""
     return util.pconvert(path)
 
 @templatefilter('splitlines', intype=bytes)
 def splitlines(text):
     """Any text. Split text into a list of lines."""
     return templateutil.hybridlist(text.splitlines(), name='line')
 
 @templatefilter('stringescape', intype=bytes)
 def stringescape(text):
     return stringutil.escapestr(text)
 
 @templatefilter('stringify', intype=bytes)
 def stringify(thing):
     """Any type. Turns the value into text by converting values into
     text and concatenating them.
     """
     return thing  # coerced by the intype
 
 @templatefilter('stripdir', intype=bytes)
 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', intype=bytes)
 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', intype=bytes)
 def upper(text):
     """Any text. Converts the text to uppercase."""
     return encoding.upper(text)
 
 @templatefilter('urlescape', intype=bytes)
 def urlescape(text):
     """Any text. Escapes all "special" characters. For example,
     "foo bar" becomes "foo%20bar".
     """
     return urlreq.quote(text)
 
 @templatefilter('user', intype=bytes)
 def userfilter(text):
     """Any text. Returns a short representation of a user name or email
     address."""
     return stringutil.shortuser(text)
 
 @templatefilter('emailuser', intype=bytes)
 def emailuser(text):
     """Any text. Returns the user portion of an email address."""
     return stringutil.emailuser(text)
 
 @templatefilter('utf8', intype=bytes)
 def utf8(text):
     """Any text. Converts from the local character encoding to UTF-8."""
     return encoding.fromlocal(text)
 
 @templatefilter('xmlescape', intype=bytes)
 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()