# templateutil.py - utility for template evaluation

#

# Copyright 2005, 2006 Matt Mackall <mpm@selenic.com>

#

# 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 abc

import types

from .i18n import _

from . import (

    error,

    pycompat,

    util,

)

from .utils import (

    dateutil,

    stringutil,

)

class ResourceUnavailable(error.Abort):

    pass

class TemplateNotFound(error.Abort):

    pass

class wrapped(object):

    """Object requiring extra conversion prior to displaying or processing

    as value

    Use unwrapvalue(), unwrapastype(), or unwraphybrid() to obtain the inner

    object.

    """

    __metaclass__ = abc.ABCMeta

    @abc.abstractmethod

    def itermaps(self, context):

        """Yield each template mapping"""

    @abc.abstractmethod

    def show(self, context, mapping):

        """Return a bytes or (possibly nested) generator of bytes representing

        the underlying object

        A pre-configured template may be rendered if the underlying object is

        not printable.

        """

    @abc.abstractmethod

    def tovalue(self, context, mapping):

        """Move the inner value object out or create a value representation

        A returned value must be serializable by templaterfilters.json().

        """

# stub for representing a date type; may be a real date type that can

# provide a readable string value

class date(object):

    pass

class hybrid(wrapped):

    """Wrapper for list or dict to support legacy template

    This class allows us to handle both:

    - "{files}" (legacy command-line-specific list hack) and

    - "{files % '{file}\n'}" (hgweb-style with inlining and function support)

    and to access raw values:

    - "{ifcontains(file, files, ...)}", "{ifcontains(key, extras, ...)}"

    - "{get(extras, key)}"

    - "{files|json}"

    """

    def __init__(self, gen, values, makemap, joinfmt, keytype=None):

        self._values = values

        self._makemap = makemap

        self.joinfmt = joinfmt

        self.keytype = keytype  # hint for 'x in y' where type(x) is unresolved

    def itermaps(self, context):

        makemap = self._makemap

        for x in self._values:

            yield makemap(x)

    def show(self, context, mapping):

        # TODO: switch gen to (context, mapping) API?

        gen = self._gen

        if callable(gen):

            return gen()

        return gen

    def tovalue(self, context, mapping):

        # TODO: return self._values and get rid of proxy methods

        return self

    def __contains__(self, x):

        return x in self._values

    def __getitem__(self, key):

        return self._values[key]

    def __len__(self):

        return len(self._values)

    def __iter__(self):

        return iter(self._values)

    def __getattr__(self, name):

        if name not in (r'get', r'items', r'iteritems', r'iterkeys',

                        r'itervalues', r'keys', r'values'):

            raise AttributeError(name)

        return getattr(self._values, name)

class mappable(wrapped):

    """Wrapper for non-list/dict object to support map operation

    This class allows us to handle both:

    - "{manifest}"

    - "{manifest % '{rev}:{node}'}"

    - "{manifest.rev}"

    Unlike a hybrid, this does not simulate the behavior of the underling

    value.

    """

    def __init__(self, gen, key, value, makemap):

        self._gen = gen  # generator or function returning generator

        self._key = key

        self._value = value  # may be generator of strings

        self._makemap = makemap

    def tomap(self):

        return self._makemap(self._key)

    def itermaps(self, context):

        yield self.tomap()

    def show(self, context, mapping):

        # TODO: switch gen to (context, mapping) API?

        gen = self._gen

        if gen is None:

            return pycompat.bytestr(self._value)

        if callable(gen):

            return gen()

        return gen

    def tovalue(self, context, mapping):

        return _unthunk(context, mapping, self._value)

def hybriddict(data, key='key', value='value', fmt=None, gen=None):

    """Wrap data to support both dict-like and string-like operations"""

    prefmt = pycompat.identity

    if fmt is None:

        fmt = '%s=%s'

        prefmt = pycompat.bytestr

    return hybrid(gen, data, lambda k: {key: k, value: data[k]},

                  lambda k: fmt % (prefmt(k), prefmt(data[k])))

def hybridlist(data, name, fmt=None, gen=None):

    """Wrap data to support both list-like and string-like operations"""

    prefmt = pycompat.identity

    if fmt is None:

        fmt = '%s'

        prefmt = pycompat.bytestr

    return hybrid(gen, data, lambda x: {name: x}, lambda x: fmt % prefmt(x))

def unwraphybrid(context, mapping, thing):

    """Return an object which can be stringified possibly by using a legacy

    template"""

    if not isinstance(thing, wrapped):

        return thing

    return thing.show(context, mapping)

def unwrapvalue(context, mapping, thing):

    """Move the inner value object out of the wrapper"""

    if not isinstance(thing, wrapped):

        return thing

    return thing.tovalue(context, mapping)

def wraphybridvalue(container, key, value):

    """Wrap an element of hybrid container to be mappable

    The key is passed to the makemap function of the given container, which

    should be an item generated by iter(container).

    """

    makemap = getattr(container, '_makemap', None)

    if makemap is None:

        return value

    if util.safehasattr(value, '_makemap'):

        # a nested hybrid list/dict, which has its own way of map operation

        return value

    return mappable(None, key, value, makemap)

def compatdict(context, mapping, name, data, key='key', value='value',

               fmt=None, plural=None, separator=' '):

    """Wrap data like hybriddict(), but also supports old-style list template

    This exists for backward compatibility with the old-style template. Use

    hybriddict() for new template keywords.

    """

    c = [{key: k, value: v} for k, v in data.iteritems()]

    f = _showcompatlist(context, mapping, name, c, plural, separator)

    return hybriddict(data, key=key, value=value, fmt=fmt, gen=f)

def compatlist(context, mapping, name, data, element=None, fmt=None,

               plural=None, separator=' '):

    """Wrap data like hybridlist(), but also supports old-style list template

    This exists for backward compatibility with the old-style template. Use

    hybridlist() for new template keywords.

    """

    f = _showcompatlist(context, mapping, name, data, plural, separator)

    return hybridlist(data, name=element or name, fmt=fmt, gen=f)

def _showcompatlist(context, mapping, name, values, plural=None, separator=' '):

    """Return a generator that renders old-style list template

    name is name of key in template map.

    values is list of strings or dicts.

    plural is plural of name, if not simply name + 's'.

    separator is used to join values as a string

    expansion works like this, given name 'foo'.

    if values is empty, expand 'no_foos'.

    if 'foo' not in template map, return values as a string,

    joined by 'separator'.

    expand 'start_foos'.

    for each value, expand 'foo'. if 'last_foo' in template

    map, expand it instead of 'foo' for last key.

    expand 'end_foos'.

    """

    if not plural:

        plural = name + 's'

    if not values:

        noname = 'no_' + plural

        if context.preload(noname):

            yield context.process(noname, mapping)

        return

    if not context.preload(name):

        if isinstance(values[0], bytes):

            yield separator.join(values)

        else:

            for v in values:

                r = dict(v)

                r.update(mapping)

                yield r

        return

    startname = 'start_' + plural

    if context.preload(startname):

        yield context.process(startname, mapping)

    def one(v, tag=name):

        vmapping = {}

        try:

            vmapping.update(v)

        # Python 2 raises ValueError if the type of v is wrong. Python

        # 3 raises TypeError.

        except (AttributeError, TypeError, ValueError):

            try:

                # Python 2 raises ValueError trying to destructure an e.g.

                # bytes. Python 3 raises TypeError.

                for a, b in v:

                    vmapping[a] = b

            except (TypeError, ValueError):

                vmapping[name] = v

        vmapping = context.overlaymap(mapping, vmapping)

        return context.process(tag, vmapping)

    lastname = 'last_' + name

    if context.preload(lastname):

        last = values.pop()

    else:

        last = None

    for v in values:

        yield one(v)

    if last is not None:

        yield one(last, tag=lastname)

    endname = 'end_' + plural

    if context.preload(endname):

        yield context.process(endname, mapping)

def flatten(context, mapping, thing):

    """Yield a single stream from a possibly nested set of iterators"""

    thing = unwraphybrid(context, mapping, thing)

    if isinstance(thing, bytes):

        yield thing

    elif isinstance(thing, str):

        # We can only hit this on Python 3, and it's here to guard

        # against infinite recursion.

        raise error.ProgrammingError('Mercurial IO including templates is done'

                                     ' with bytes, not strings, got %r' % thing)

    elif thing is None:

        pass

    elif not util.safehasattr(thing, '__iter__'):

        yield pycompat.bytestr(thing)

    else:

        for i in thing:

            i = unwraphybrid(context, mapping, i)

            if isinstance(i, bytes):

                yield i

            elif i is None:

                pass

            elif not util.safehasattr(i, '__iter__'):

                yield pycompat.bytestr(i)

            else:

                for j in flatten(context, mapping, i):

                    yield j

def stringify(context, mapping, thing):

    """Turn values into bytes by converting into text and concatenating them"""

    if isinstance(thing, bytes):

        return thing  # retain localstr to be round-tripped

    return b''.join(flatten(context, mapping, thing))

def findsymbolicname(arg):

    """Find symbolic name for the given compiled expression; returns None

    if nothing found reliably"""

    while True:

        func, data = arg

        if func is runsymbol:

            return data

        elif func is runfilter:

            arg = data[0]

        else:

            return None

def _unthunk(context, mapping, thing):

    """Evaluate a lazy byte string into value"""

    if not isinstance(thing, types.GeneratorType):

        return thing

    return stringify(context, mapping, thing)

def evalrawexp(context, mapping, arg):

    """Evaluate given argument as a bare template object which may require

    further processing (such as folding generator of strings)"""

    func, data = arg

    return func(context, mapping, data)

def evalfuncarg(context, mapping, arg):

    """Evaluate given argument as value type"""

    return _unwrapvalue(context, mapping, evalrawexp(context, mapping, arg))

# TODO: unify this with unwrapvalue() once the bug of templatefunc.join()

# is fixed. we can't do that right now because join() has to take a generator

# of byte strings as it is, not a lazy byte string.

def _unwrapvalue(context, mapping, thing):

    thing = unwrapvalue(context, mapping, thing)

    # evalrawexp() may return string, generator of strings or arbitrary object

    # such as date tuple, but filter does not want generator.

    return _unthunk(context, mapping, thing)

def evalboolean(context, mapping, arg):

    """Evaluate given argument as boolean, but also takes boolean literals"""

    func, data = arg

    if func is runsymbol:

        thing = func(context, mapping, data, default=None)

        if thing is None:

            # not a template keyword, takes as a boolean literal

            thing = stringutil.parsebool(data)

    else:

        thing = func(context, mapping, data)

    thing = unwrapvalue(context, mapping, thing)

    if isinstance(thing, bool):

        return thing

    # other objects are evaluated as strings, which means 0 is True, but

    # empty dict/list should be False as they are expected to be ''

    return bool(stringify(context, mapping, thing))

def evaldate(context, mapping, arg, err=None):

    """Evaluate given argument as a date tuple or a date string; returns

    a (unixtime, offset) tuple"""

    thing = evalrawexp(context, mapping, arg)

    return unwrapdate(context, mapping, thing, err)

def unwrapdate(context, mapping, thing, err=None):

    thing = _unwrapvalue(context, mapping, thing)

    try:

        return dateutil.parsedate(thing)

    except AttributeError:

        raise error.ParseError(err or _('not a date tuple nor a string'))

    except error.ParseError:

        if not err:

            raise

        raise error.ParseError(err)

def evalinteger(context, mapping, arg, err=None):

    thing = evalrawexp(context, mapping, arg)

    return unwrapinteger(context, mapping, thing, err)

def unwrapinteger(context, mapping, thing, err=None):

    thing = _unwrapvalue(context, mapping, thing)

    try:

        return int(thing)

    except (TypeError, ValueError):

        raise error.ParseError(err or _('not an integer'))

def evalstring(context, mapping, arg):

    return stringify(context, mapping, evalrawexp(context, mapping, arg))

def evalstringliteral(context, mapping, arg):

    """Evaluate given argument as string template, but returns symbol name

    if it is unknown"""

    func, data = arg

    if func is runsymbol:

        thing = func(context, mapping, data, default=data)

    else:

        thing = func(context, mapping, data)

    return stringify(context, mapping, thing)

_unwrapfuncbytype = {

    None: _unwrapvalue,

    bytes: stringify,

    date: unwrapdate,

    int: unwrapinteger,

}

def unwrapastype(context, mapping, thing, typ):

    """Move the inner value object out of the wrapper and coerce its type"""

    try:

        f = _unwrapfuncbytype[typ]

    except KeyError:

        raise error.ProgrammingError('invalid type specified: %r' % typ)

    return f(context, mapping, thing)

def runinteger(context, mapping, data):

    return int(data)

def runstring(context, mapping, data):

    return data

def _recursivesymbolblocker(key):

    def showrecursion(**args):

        raise error.Abort(_("recursive reference '%s' in template") % key)

    return showrecursion

def runsymbol(context, mapping, key, default=''):

    v = context.symbol(mapping, key)

    if v is None:

        # put poison to cut recursion. we can't move this to parsing phase

        # because "x = {x}" is allowed if "x" is a keyword. (issue4758)

        safemapping = mapping.copy()

        safemapping[key] = _recursivesymbolblocker(key)

        try:

            v = context.process(key, safemapping)

        except TemplateNotFound:

            v = default

    if callable(v) and getattr(v, '_requires', None) is None:

        # old templatekw: expand all keywords and resources

        # (TODO: deprecate this after porting web template keywords to new API)

        props = {k: context._resources.lookup(context, mapping, k)

                 for k in context._resources.knownkeys()}

        # pass context to _showcompatlist() through templatekw._showlist()

        props['templ'] = context

        props.update(mapping)

        return v(**pycompat.strkwargs(props))

    if callable(v):

        # new templatekw

        try:

            return v(context, mapping)

        except ResourceUnavailable:

            # unsupported keyword is mapped to empty just like unknown keyword

            return None

    return v

def runtemplate(context, mapping, template):

    for arg in template:

        yield evalrawexp(context, mapping, arg)

def runfilter(context, mapping, data):

    arg, filt = data

    thing = evalrawexp(context, mapping, arg)

    intype = getattr(filt, '_intype', None)

    try:

        thing = unwrapastype(context, mapping, thing, intype)

        return filt(thing)

    except error.ParseError as e:

        raise error.ParseError(bytes(e), hint=_formatfiltererror(arg, filt))

def _formatfiltererror(arg, filt):