mercurial/templatefilters.py

check-code: catch Python 'is' comparing number or string literals

The Python 'is' operator compares object identity, so it should
definitely not be applied to string or number literals, which Python
implementations are free to represent with a temporary object.

This should catch the following kinds of bogus expressions (examples):

  x is 'foo'     x is not 'foo'
  x is "bar"     x is not "bar"
  x is 42        x is not 42
  x is -36       x is not -36

As originally proposed by Martin Geisler, amended with catching
negative numbers.

# template-filters.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.

import cgi, re, os, time, urllib
import encoding, node, util

def stringify(thing):
    '''turn nested template iterator into string.'''
    if hasattr(thing, '__iter__') and not isinstance(thing, str):
        return "".join([stringify(t) for t in thing if t is not None])
    return str(thing)

agescales = [("year", 3600 * 24 * 365),
             ("month", 3600 * 24 * 30),
             ("week", 3600 * 24 * 7),
             ("day", 3600 * 24),
             ("hour", 3600),
             ("minute", 60),
             ("second", 1)]

def age(date):
    '''turn a (timestamp, tzoff) tuple into an age string.'''

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

    now = time.time()
    then = date[0]
    if then > now:
        return 'in the future'

    delta = max(1, int(now - then))
    if delta > agescales[0][1] * 2:
        return util.shortdate(date)

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

para_re = None
space_re = None

def fill(text, width):
    '''fill many paragraphs.'''
    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(r'  +')

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

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

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

def nl2br(text):
    '''replace raw newlines with xhtml line breaks.'''
    return text.replace('\n', '<br/>\n')

def obfuscate(text):
    text = unicode(text, encoding.encoding, 'replace')
    return ''.join(['&#%d;' % ord(c) for c in text])

def domain(author):
    '''get domain of author, or empty string if none.'''
    f = author.find('@')
    if f == -1:
        return ''
    author = author[f + 1:]
    f = author.find('>')
    if f >= 0:
        author = author[:f]
    return author

def person(author):
    '''get name of author, or else username.'''
    if not '@' in author:
        return author
    f = author.find('<')
    if f == -1:
        return util.shortuser(author)
    return author[:f].rstrip()

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())

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

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 uescape(c):
    if ord(c) < 0x80:
        return c
    else:
        return '\\u%04x' % ord(c)

_escapes = [
    ('\\', '\\\\'), ('"', '\\"'), ('\t', '\\t'), ('\n', '\\n'),
    ('\r', '\\r'), ('\f', '\\f'), ('\b', '\\b'),
]

def jsonescape(s):
    for k, v in _escapes:
        s = s.replace(k, v)
    return ''.join(uescape(c) for c in s)

def json(obj):
    if obj is None or obj is False or obj is True:
        return {None: 'null', False: 'false', True: 'true'}[obj]
    elif isinstance(obj, int) or isinstance(obj, float):
        return str(obj)
    elif isinstance(obj, str):
        u = unicode(obj, encoding.encoding, 'replace')
        return '"%s"' % jsonescape(u)
    elif isinstance(obj, unicode):
        return '"%s"' % jsonescape(obj)
    elif hasattr(obj, 'keys'):
        out = []
        for k, v in obj.iteritems():
            s = '%s: %s' % (json(k), json(v))
            out.append(s)
        return '{' + ', '.join(out) + '}'
    elif hasattr(obj, '__iter__'):
        out = []
        for i in obj:
            out.append(json(i))
        return '[' + ', '.join(out) + ']'
    else:
        raise TypeError('cannot encode type %s' % obj.__class__.__name__)

def stripdir(text):
    '''Treat the text as path and strip a directory level, if possible.'''
    dir = os.path.dirname(text)
    if dir == "":
        return os.path.basename(text)
    else:
        return dir

def nonempty(str):
    return str or "(none)"

filters = {
    "addbreaks": nl2br,
    "basename": os.path.basename,
    "stripdir": stripdir,
    "age": age,
    "date": lambda x: util.datestr(x),
    "domain": domain,
    "email": util.email,
    "escape": lambda x: cgi.escape(x, True),
    "fill68": lambda x: fill(x, width=68),
    "fill76": lambda x: fill(x, width=76),
    "firstline": firstline,
    "tabindent": lambda x: indent(x, '\t'),
    "hgdate": lambda x: "%d %d" % x,
    "isodate": lambda x: util.datestr(x, '%Y-%m-%d %H:%M %1%2'),
    "isodatesec": lambda x: util.datestr(x, '%Y-%m-%d %H:%M:%S %1%2'),
    "json": json,
    "jsonescape": jsonescape,
    "localdate": lambda x: (x[0], util.makedate()[1]),
    "nonempty": nonempty,
    "obfuscate": obfuscate,
    "permissions": permissions,
    "person": person,
    "rfc822date": lambda x: util.datestr(x, "%a, %d %b %Y %H:%M:%S %1%2"),
    "rfc3339date": lambda x: util.datestr(x, "%Y-%m-%dT%H:%M:%S%1:%2"),
    "hex": node.hex,
    "short": lambda x: x[:12],
    "shortdate": util.shortdate,
    "stringify": stringify,
    "strip": lambda x: x.strip(),
    "urlescape": lambda x: urllib.quote(x),
    "user": lambda x: util.shortuser(x),
    "stringescape": lambda x: x.encode('string_escape'),
    "xmlescape": xmlescape,
}