mercurial/templater.py

hgweb: display diff for a changeset against any parents (issue2810)

During merge of branches, it is useful to compare merge results against
the two parents.  This change adds this support to hgweb.  To specify
which parent to compare to, use rev/12300:12345 where 12300 is a
parent changeset number.  Two links are added to changeset web page so
that one can choose which parent to compare to.

# templater.py - template expansion for output
#
# 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 i18n import _
import sys, os, re
import util, config, templatefilters, parser, error
import types

# template parsing

elements = {
    "(": (20, ("group", 1, ")"), ("func", 1, ")")),
    ",": (2, None, ("list", 2)),
    "|": (5, None, ("|", 5)),
    "%": (6, None, ("%", 6)),
    ")": (0, None, None),
    "symbol": (0, ("symbol",), None),
    "string": (0, ("string",), None),
    "end": (0, None, None),
}

def tokenizer(data):
    program, start, end = data
    pos = start
    while pos < end:
        c = program[pos]
        if c.isspace(): # skip inter-token whitespace
            pass
        elif c in "(,)%|": # handle simple operators
            yield (c, None, pos)
        elif (c in '"\'' or c == 'r' and
              program[pos:pos + 2] in ("r'", 'r"')): # handle quoted strings
            if c == 'r':
                pos += 1
                c = program[pos]
                decode = False
            else:
                decode = True
            pos += 1
            s = pos
            while pos < end: # find closing quote
                d = program[pos]
                if decode and d == '\\': # skip over escaped characters
                    pos += 2
                    continue
                if d == c:
                    if not decode:
                        yield ('string', program[s:pos].replace('\\', r'\\'), s)
                        break
                    yield ('string', program[s:pos].decode('string-escape'), s)
                    break
                pos += 1
            else:
                raise error.ParseError(_("unterminated string"), s)
        elif c.isalnum() or c in '_':
            s = pos
            pos += 1
            while pos < end: # find end of symbol
                d = program[pos]
                if not (d.isalnum() or d == "_"):
                    break
                pos += 1
            sym = program[s:pos]
            yield ('symbol', sym, s)
            pos -= 1
        elif c == '}':
            pos += 1
            break
        else:
            raise error.ParseError(_("syntax error"), pos)
        pos += 1
    yield ('end', None, pos)

def compiletemplate(tmpl, context):
    parsed = []
    pos, stop = 0, len(tmpl)
    p = parser.parser(tokenizer, elements)

    while pos < stop:
        n = tmpl.find('{', pos)
        if n < 0:
            parsed.append(("string", tmpl[pos:]))
            break
        if n > 0 and tmpl[n - 1] == '\\':
            # escaped
            parsed.append(("string", tmpl[pos:n - 1] + "{"))
            pos = n + 1
            continue
        if n > pos:
            parsed.append(("string", tmpl[pos:n]))

        pd = [tmpl, n + 1, stop]
        parseres, pos = p.parse(pd)
        parsed.append(parseres)

    return [compileexp(e, context) for e in parsed]

def compileexp(exp, context):
    t = exp[0]
    if t in methods:
        return methods[t](exp, context)
    raise error.ParseError(_("unknown method '%s'") % t)

# template evaluation

def getsymbol(exp):
    if exp[0] == 'symbol':
        return exp[1]
    raise error.ParseError(_("expected a symbol"))

def getlist(x):
    if not x:
        return []
    if x[0] == 'list':
        return getlist(x[1]) + [x[2]]
    return [x]

def getfilter(exp, context):
    f = getsymbol(exp)
    if f not in context._filters:
        raise error.ParseError(_("unknown function '%s'") % f)
    return context._filters[f]

def gettemplate(exp, context):
    if exp[0] == 'string':
        return compiletemplate(exp[1], context)
    if exp[0] == 'symbol':
        return context._load(exp[1])
    raise error.ParseError(_("expected template specifier"))

def runstring(context, mapping, data):
    return data

def runsymbol(context, mapping, key):
    v = mapping.get(key)
    if v is None:
        v = context._defaults.get(key, '')
    if util.safehasattr(v, '__call__'):
        return v(**mapping)
    if isinstance(v, types.GeneratorType):
        v = list(v)
        mapping[key] = v
        return v
    return v

def buildfilter(exp, context):
    func, data = compileexp(exp[1], context)
    filt = getfilter(exp[2], context)
    return (runfilter, (func, data, filt))

def runfilter(context, mapping, data):
    func, data, filt = data
    try:
        return filt(func(context, mapping, data))
    except (ValueError, AttributeError, TypeError):
        if isinstance(data, tuple):
            dt = data[1]
        else:
            dt = data
        raise util.Abort(_("template filter '%s' is not compatible with "
                           "keyword '%s'") % (filt.func_name, dt))

def buildmap(exp, context):
    func, data = compileexp(exp[1], context)
    ctmpl = gettemplate(exp[2], context)
    return (runmap, (func, data, ctmpl))

def runtemplate(context, mapping, template):
    for func, data in template:
        yield func(context, mapping, data)

def runmap(context, mapping, data):
    func, data, ctmpl = data
    d = func(context, mapping, data)
    if util.safehasattr(d, '__call__'):
        d = d()

    lm = mapping.copy()

    for i in d:
        if isinstance(i, dict):
            lm.update(i)
            lm['originalnode'] = mapping.get('node')
            yield runtemplate(context, lm, ctmpl)
        else:
            # v is not an iterable of dicts, this happen when 'key'
            # has been fully expanded already and format is useless.
            # If so, return the expanded value.
            yield i

def buildfunc(exp, context):
    n = getsymbol(exp[1])
    args = [compileexp(x, context) for x in getlist(exp[2])]
    if n in funcs:
        f = funcs[n]
        return (f, args)
    if n in templatefilters.funcs:
        f = templatefilters.funcs[n]
        return (f, args)
    if n in context._filters:
        if len(args) != 1:
            raise error.ParseError(_("filter %s expects one argument") % n)
        f = context._filters[n]
        return (runfilter, (args[0][0], args[0][1], f))

def join(context, mapping, args):
    if not (1 <= len(args) <= 2):
        # i18n: "join" is a keyword
        raise error.ParseError(_("join expects one or two arguments"))

    joinset = args[0][0](context, mapping, args[0][1])
    if util.safehasattr(joinset, '__call__'):
        joinset = [x.values()[0] for x in joinset()]

    joiner = " "
    if len(args) > 1:
        joiner = args[1][0](context, mapping, args[1][1])

    first = True
    for x in joinset:
        if first:
            first = False
        else:
            yield joiner
        yield x

def sub(context, mapping, args):
    if len(args) != 3:
        # i18n: "sub" is a keyword
        raise error.ParseError(_("sub expects three arguments"))

    pat = stringify(args[0][0](context, mapping, args[0][1]))
    rpl = stringify(args[1][0](context, mapping, args[1][1]))
    src = stringify(args[2][0](context, mapping, args[2][1]))
    yield re.sub(pat, rpl, src)

def if_(context, mapping, args):
    if not (2 <= len(args) <= 3):
        # i18n: "if" is a keyword
        raise error.ParseError(_("if expects two or three arguments"))

    test = stringify(args[0][0](context, mapping, args[0][1]))
    if test:
        t = stringify(args[1][0](context, mapping, args[1][1]))
        yield runtemplate(context, mapping, compiletemplate(t, context))
    elif len(args) == 3:
        t = stringify(args[2][0](context, mapping, args[2][1]))
        yield runtemplate(context, mapping, compiletemplate(t, context))

def ifeq(context, mapping, args):
    if not (3 <= len(args) <= 4):
        # i18n: "ifeq" is a keyword
        raise error.ParseError(_("ifeq expects three or four arguments"))

    test = stringify(args[0][0](context, mapping, args[0][1]))
    match = stringify(args[1][0](context, mapping, args[1][1]))
    if test == match:
        t = stringify(args[2][0](context, mapping, args[2][1]))
        yield runtemplate(context, mapping, compiletemplate(t, context))
    elif len(args) == 4:
        t = stringify(args[3][0](context, mapping, args[3][1]))
        yield runtemplate(context, mapping, compiletemplate(t, context))

methods = {
    "string": lambda e, c: (runstring, e[1]),
    "symbol": lambda e, c: (runsymbol, e[1]),
    "group": lambda e, c: compileexp(e[1], c),
#    ".": buildmember,
    "|": buildfilter,
    "%": buildmap,
    "func": buildfunc,
    }

funcs = {
    "if": if_,
    "ifeq": ifeq,
    "join": join,
    "sub": sub,
}

# template engine

path = ['templates', '../templates']
stringify = templatefilters.stringify

def _flatten(thing):
    '''yield a single stream from a possibly nested set of iterators'''
    if isinstance(thing, str):
        yield thing
    elif not util.safehasattr(thing, '__iter__'):
        if thing is not None:
            yield str(thing)
    else:
        for i in thing:
            if isinstance(i, str):
                yield i
            elif not util.safehasattr(i, '__iter__'):
                if i is not None:
                    yield str(i)
            elif i is not None:
                for j in _flatten(i):
                    yield j

def parsestring(s, quoted=True):
    '''parse a string using simple c-like syntax.
    string must be in quotes if quoted is True.'''
    if quoted:
        if len(s) < 2 or s[0] != s[-1]:
            raise SyntaxError(_('unmatched quotes'))
        return s[1:-1].decode('string_escape')

    return s.decode('string_escape')

class engine(object):
    '''template expansion engine.

    template expansion works like this. a map file contains key=value
    pairs. if value is quoted, it is treated as string. otherwise, it
    is treated as name of template file.

    templater is asked to expand a key in map. it looks up key, and
    looks for strings like this: {foo}. it expands {foo} by looking up
    foo in map, and substituting it. expansion is recursive: it stops
    when there is no more {foo} to replace.

    expansion also allows formatting and filtering.

    format uses key to expand each item in list. syntax is
    {key%format}.

    filter uses function to transform value. syntax is
    {key|filter1|filter2|...}.'''

    def __init__(self, loader, filters={}, defaults={}):
        self._loader = loader
        self._filters = filters
        self._defaults = defaults
        self._cache = {}

    def _load(self, t):
        '''load, parse, and cache a template'''
        if t not in self._cache:
            self._cache[t] = compiletemplate(self._loader(t), self)
        return self._cache[t]

    def process(self, t, mapping):
        '''Perform expansion. t is name of map element to expand.
        mapping contains added elements for use during expansion. Is a
        generator.'''
        return _flatten(runtemplate(self, mapping, self._load(t)))

engines = {'default': engine}

class templater(object):

    def __init__(self, mapfile, filters={}, defaults={}, cache={},
                 minchunk=1024, maxchunk=65536):
        '''set up template engine.
        mapfile is name of file to read map definitions from.
        filters is dict of functions. each transforms a value into another.
        defaults is dict of default map definitions.'''
        self.mapfile = mapfile or 'template'
        self.cache = cache.copy()
        self.map = {}
        self.base = (mapfile and os.path.dirname(mapfile)) or ''
        self.filters = templatefilters.filters.copy()
        self.filters.update(filters)
        self.defaults = defaults
        self.minchunk, self.maxchunk = minchunk, maxchunk
        self.ecache = {}

        if not mapfile:
            return
        if not os.path.exists(mapfile):
            raise util.Abort(_('style not found: %s') % mapfile)

        conf = config.config()
        conf.read(mapfile)

        for key, val in conf[''].items():
            if not val:
                raise SyntaxError(_('%s: missing value') % conf.source('', key))
            if val[0] in "'\"":
                try:
                    self.cache[key] = parsestring(val)
                except SyntaxError, inst:
                    raise SyntaxError('%s: %s' %
                                      (conf.source('', key), inst.args[0]))
            else:
                val = 'default', val
                if ':' in val[1]:
                    val = val[1].split(':', 1)
                self.map[key] = val[0], os.path.join(self.base, val[1])

    def __contains__(self, key):
        return key in self.cache or key in self.map

    def load(self, t):
        '''Get the template for the given template name. Use a local cache.'''
        if t not in self.cache:
            try:
                self.cache[t] = util.readfile(self.map[t][1])
            except KeyError, inst:
                raise util.Abort(_('"%s" not in template map') % inst.args[0])
            except IOError, inst:
                raise IOError(inst.args[0], _('template file %s: %s') %
                              (self.map[t][1], inst.args[1]))
        return self.cache[t]

    def __call__(self, t, **mapping):
        ttype = t in self.map and self.map[t][0] or 'default'
        if ttype not in self.ecache:
            self.ecache[ttype] = engines[ttype](self.load,
                                                 self.filters, self.defaults)
        proc = self.ecache[ttype]

        stream = proc.process(t, mapping)
        if self.minchunk:
            stream = util.increasingchunks(stream, min=self.minchunk,
                                           max=self.maxchunk)
        return stream

def templatepath(name=None):
    '''return location of template file or directory (if no name).
    returns None if not found.'''
    normpaths = []

    # executable version (py2exe) doesn't support __file__
    if util.mainfrozen():
        module = sys.executable
    else:
        module = __file__
    for f in path:
        if f.startswith('/'):
            p = f
        else:
            fl = f.split('/')
            p = os.path.join(os.path.dirname(module), *fl)
        if name:
            p = os.path.join(p, name)
        if name and os.path.exists(p):
            return os.path.normpath(p)
        elif os.path.isdir(p):
            normpaths.append(os.path.normpath(p))

    return normpaths

def stylemap(styles, paths=None):
    """Return path to mapfile for a given style.

    Searches mapfile in the following locations:
    1. templatepath/style/map
    2. templatepath/map-style
    3. templatepath/map
    """

    if paths is None:
        paths = templatepath()
    elif isinstance(paths, str):
        paths = [paths]

    if isinstance(styles, str):
        styles = [styles]

    for style in styles:
        if not style:
            continue
        locations = [os.path.join(style, 'map'), 'map-' + style]
        locations.append('map')

        for path in paths:
            for location in locations:
                mapfile = os.path.join(path, location)
                if os.path.isfile(mapfile):
                    return style, mapfile

    raise RuntimeError("No hgweb templates found in %r" % paths)