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Direktori : /proc/thread-self/root/proc/thread-self/root/lib/python2.7/site-packages/jinja2/ |
Current File : //proc/thread-self/root/proc/thread-self/root/lib/python2.7/site-packages/jinja2/ext.py |
# -*- coding: utf-8 -*- """ jinja2.ext ~~~~~~~~~~ Jinja extensions allow to add custom tags similar to the way django custom tags work. By default two example extensions exist: an i18n and a cache extension. :copyright: (c) 2010 by the Jinja Team. :license: BSD. """ from jinja2 import nodes from jinja2.defaults import BLOCK_START_STRING, \ BLOCK_END_STRING, VARIABLE_START_STRING, VARIABLE_END_STRING, \ COMMENT_START_STRING, COMMENT_END_STRING, LINE_STATEMENT_PREFIX, \ LINE_COMMENT_PREFIX, TRIM_BLOCKS, NEWLINE_SEQUENCE, \ KEEP_TRAILING_NEWLINE, LSTRIP_BLOCKS from jinja2.environment import Environment from jinja2.runtime import concat from jinja2.exceptions import TemplateAssertionError, TemplateSyntaxError from jinja2.utils import contextfunction, import_string, Markup from jinja2._compat import next, with_metaclass, string_types, iteritems # the only real useful gettext functions for a Jinja template. Note # that ugettext must be assigned to gettext as Jinja doesn't support # non unicode strings. GETTEXT_FUNCTIONS = ('_', 'gettext', 'ngettext') class ExtensionRegistry(type): """Gives the extension an unique identifier.""" def __new__(cls, name, bases, d): rv = type.__new__(cls, name, bases, d) rv.identifier = rv.__module__ + '.' + rv.__name__ return rv class Extension(with_metaclass(ExtensionRegistry, object)): """Extensions can be used to add extra functionality to the Jinja template system at the parser level. Custom extensions are bound to an environment but may not store environment specific data on `self`. The reason for this is that an extension can be bound to another environment (for overlays) by creating a copy and reassigning the `environment` attribute. As extensions are created by the environment they cannot accept any arguments for configuration. One may want to work around that by using a factory function, but that is not possible as extensions are identified by their import name. The correct way to configure the extension is storing the configuration values on the environment. Because this way the environment ends up acting as central configuration storage the attributes may clash which is why extensions have to ensure that the names they choose for configuration are not too generic. ``prefix`` for example is a terrible name, ``fragment_cache_prefix`` on the other hand is a good name as includes the name of the extension (fragment cache). """ #: if this extension parses this is the list of tags it's listening to. tags = set() #: the priority of that extension. This is especially useful for #: extensions that preprocess values. A lower value means higher #: priority. #: #: .. versionadded:: 2.4 priority = 100 def __init__(self, environment): self.environment = environment def bind(self, environment): """Create a copy of this extension bound to another environment.""" rv = object.__new__(self.__class__) rv.__dict__.update(self.__dict__) rv.environment = environment return rv def preprocess(self, source, name, filename=None): """This method is called before the actual lexing and can be used to preprocess the source. The `filename` is optional. The return value must be the preprocessed source. """ return source def filter_stream(self, stream): """It's passed a :class:`~jinja2.lexer.TokenStream` that can be used to filter tokens returned. This method has to return an iterable of :class:`~jinja2.lexer.Token`\s, but it doesn't have to return a :class:`~jinja2.lexer.TokenStream`. In the `ext` folder of the Jinja2 source distribution there is a file called `inlinegettext.py` which implements a filter that utilizes this method. """ return stream def parse(self, parser): """If any of the :attr:`tags` matched this method is called with the parser as first argument. The token the parser stream is pointing at is the name token that matched. This method has to return one or a list of multiple nodes. """ raise NotImplementedError() def attr(self, name, lineno=None): """Return an attribute node for the current extension. This is useful to pass constants on extensions to generated template code. :: self.attr('_my_attribute', lineno=lineno) """ return nodes.ExtensionAttribute(self.identifier, name, lineno=lineno) def call_method(self, name, args=None, kwargs=None, dyn_args=None, dyn_kwargs=None, lineno=None): """Call a method of the extension. This is a shortcut for :meth:`attr` + :class:`jinja2.nodes.Call`. """ if args is None: args = [] if kwargs is None: kwargs = [] return nodes.Call(self.attr(name, lineno=lineno), args, kwargs, dyn_args, dyn_kwargs, lineno=lineno) @contextfunction def _gettext_alias(__context, *args, **kwargs): return __context.call(__context.resolve('gettext'), *args, **kwargs) def _make_new_gettext(func): @contextfunction def gettext(__context, __string, **variables): rv = __context.call(func, __string) if __context.eval_ctx.autoescape: rv = Markup(rv) return rv % variables return gettext def _make_new_ngettext(func): @contextfunction def ngettext(__context, __singular, __plural, __num, **variables): variables.setdefault('num', __num) rv = __context.call(func, __singular, __plural, __num) if __context.eval_ctx.autoescape: rv = Markup(rv) return rv % variables return ngettext class InternationalizationExtension(Extension): """This extension adds gettext support to Jinja2.""" tags = set(['trans']) # TODO: the i18n extension is currently reevaluating values in a few # situations. Take this example: # {% trans count=something() %}{{ count }} foo{% pluralize # %}{{ count }} fooss{% endtrans %} # something is called twice here. One time for the gettext value and # the other time for the n-parameter of the ngettext function. def __init__(self, environment): Extension.__init__(self, environment) environment.globals['_'] = _gettext_alias environment.extend( install_gettext_translations=self._install, install_null_translations=self._install_null, install_gettext_callables=self._install_callables, uninstall_gettext_translations=self._uninstall, extract_translations=self._extract, newstyle_gettext=False ) def _install(self, translations, newstyle=None): gettext = getattr(translations, 'ugettext', None) if gettext is None: gettext = translations.gettext ngettext = getattr(translations, 'ungettext', None) if ngettext is None: ngettext = translations.ngettext self._install_callables(gettext, ngettext, newstyle) def _install_null(self, newstyle=None): self._install_callables( lambda x: x, lambda s, p, n: (n != 1 and (p,) or (s,))[0], newstyle ) def _install_callables(self, gettext, ngettext, newstyle=None): if newstyle is not None: self.environment.newstyle_gettext = newstyle if self.environment.newstyle_gettext: gettext = _make_new_gettext(gettext) ngettext = _make_new_ngettext(ngettext) self.environment.globals.update( gettext=gettext, ngettext=ngettext ) def _uninstall(self, translations): for key in 'gettext', 'ngettext': self.environment.globals.pop(key, None) def _extract(self, source, gettext_functions=GETTEXT_FUNCTIONS): if isinstance(source, string_types): source = self.environment.parse(source) return extract_from_ast(source, gettext_functions) def parse(self, parser): """Parse a translatable tag.""" lineno = next(parser.stream).lineno num_called_num = False # find all the variables referenced. Additionally a variable can be # defined in the body of the trans block too, but this is checked at # a later state. plural_expr = None plural_expr_assignment = None variables = {} while parser.stream.current.type != 'block_end': if variables: parser.stream.expect('comma') # skip colon for python compatibility if parser.stream.skip_if('colon'): break name = parser.stream.expect('name') if name.value in variables: parser.fail('translatable variable %r defined twice.' % name.value, name.lineno, exc=TemplateAssertionError) # expressions if parser.stream.current.type == 'assign': next(parser.stream) variables[name.value] = var = parser.parse_expression() else: variables[name.value] = var = nodes.Name(name.value, 'load') if plural_expr is None: if isinstance(var, nodes.Call): plural_expr = nodes.Name('_trans', 'load') variables[name.value] = plural_expr plural_expr_assignment = nodes.Assign( nodes.Name('_trans', 'store'), var) else: plural_expr = var num_called_num = name.value == 'num' parser.stream.expect('block_end') plural = plural_names = None have_plural = False referenced = set() # now parse until endtrans or pluralize singular_names, singular = self._parse_block(parser, True) if singular_names: referenced.update(singular_names) if plural_expr is None: plural_expr = nodes.Name(singular_names[0], 'load') num_called_num = singular_names[0] == 'num' # if we have a pluralize block, we parse that too if parser.stream.current.test('name:pluralize'): have_plural = True next(parser.stream) if parser.stream.current.type != 'block_end': name = parser.stream.expect('name') if name.value not in variables: parser.fail('unknown variable %r for pluralization' % name.value, name.lineno, exc=TemplateAssertionError) plural_expr = variables[name.value] num_called_num = name.value == 'num' parser.stream.expect('block_end') plural_names, plural = self._parse_block(parser, False) next(parser.stream) referenced.update(plural_names) else: next(parser.stream) # register free names as simple name expressions for var in referenced: if var not in variables: variables[var] = nodes.Name(var, 'load') if not have_plural: plural_expr = None elif plural_expr is None: parser.fail('pluralize without variables', lineno) node = self._make_node(singular, plural, variables, plural_expr, bool(referenced), num_called_num and have_plural) node.set_lineno(lineno) if plural_expr_assignment is not None: return [plural_expr_assignment, node] else: return node def _parse_block(self, parser, allow_pluralize): """Parse until the next block tag with a given name.""" referenced = [] buf = [] while 1: if parser.stream.current.type == 'data': buf.append(parser.stream.current.value.replace('%', '%%')) next(parser.stream) elif parser.stream.current.type == 'variable_begin': next(parser.stream) name = parser.stream.expect('name').value referenced.append(name) buf.append('%%(%s)s' % name) parser.stream.expect('variable_end') elif parser.stream.current.type == 'block_begin': next(parser.stream) if parser.stream.current.test('name:endtrans'): break elif parser.stream.current.test('name:pluralize'): if allow_pluralize: break parser.fail('a translatable section can have only one ' 'pluralize section') parser.fail('control structures in translatable sections are ' 'not allowed') elif parser.stream.eos: parser.fail('unclosed translation block') else: assert False, 'internal parser error' return referenced, concat(buf) def _make_node(self, singular, plural, variables, plural_expr, vars_referenced, num_called_num): """Generates a useful node from the data provided.""" # no variables referenced? no need to escape for old style # gettext invocations only if there are vars. if not vars_referenced and not self.environment.newstyle_gettext: singular = singular.replace('%%', '%') if plural: plural = plural.replace('%%', '%') # singular only: if plural_expr is None: gettext = nodes.Name('gettext', 'load') node = nodes.Call(gettext, [nodes.Const(singular)], [], None, None) # singular and plural else: ngettext = nodes.Name('ngettext', 'load') node = nodes.Call(ngettext, [ nodes.Const(singular), nodes.Const(plural), plural_expr ], [], None, None) # in case newstyle gettext is used, the method is powerful # enough to handle the variable expansion and autoescape # handling itself if self.environment.newstyle_gettext: for key, value in iteritems(variables): # the function adds that later anyways in case num was # called num, so just skip it. if num_called_num and key == 'num': continue node.kwargs.append(nodes.Keyword(key, value)) # otherwise do that here else: # mark the return value as safe if we are in an # environment with autoescaping turned on node = nodes.MarkSafeIfAutoescape(node) if variables: node = nodes.Mod(node, nodes.Dict([ nodes.Pair(nodes.Const(key), value) for key, value in variables.items() ])) return nodes.Output([node]) class ExprStmtExtension(Extension): """Adds a `do` tag to Jinja2 that works like the print statement just that it doesn't print the return value. """ tags = set(['do']) def parse(self, parser): node = nodes.ExprStmt(lineno=next(parser.stream).lineno) node.node = parser.parse_tuple() return node class LoopControlExtension(Extension): """Adds break and continue to the template engine.""" tags = set(['break', 'continue']) def parse(self, parser): token = next(parser.stream) if token.value == 'break': return nodes.Break(lineno=token.lineno) return nodes.Continue(lineno=token.lineno) class WithExtension(Extension): """Adds support for a django-like with block.""" tags = set(['with']) def parse(self, parser): node = nodes.Scope(lineno=next(parser.stream).lineno) assignments = [] while parser.stream.current.type != 'block_end': lineno = parser.stream.current.lineno if assignments: parser.stream.expect('comma') target = parser.parse_assign_target() parser.stream.expect('assign') expr = parser.parse_expression() assignments.append(nodes.Assign(target, expr, lineno=lineno)) node.body = assignments + \ list(parser.parse_statements(('name:endwith',), drop_needle=True)) return node class AutoEscapeExtension(Extension): """Changes auto escape rules for a scope.""" tags = set(['autoescape']) def parse(self, parser): node = nodes.ScopedEvalContextModifier(lineno=next(parser.stream).lineno) node.options = [ nodes.Keyword('autoescape', parser.parse_expression()) ] node.body = parser.parse_statements(('name:endautoescape',), drop_needle=True) return nodes.Scope([node]) def extract_from_ast(node, gettext_functions=GETTEXT_FUNCTIONS, babel_style=True): """Extract localizable strings from the given template node. Per default this function returns matches in babel style that means non string parameters as well as keyword arguments are returned as `None`. This allows Babel to figure out what you really meant if you are using gettext functions that allow keyword arguments for placeholder expansion. If you don't want that behavior set the `babel_style` parameter to `False` which causes only strings to be returned and parameters are always stored in tuples. As a consequence invalid gettext calls (calls without a single string parameter or string parameters after non-string parameters) are skipped. This example explains the behavior: >>> from jinja2 import Environment >>> env = Environment() >>> node = env.parse('{{ (_("foo"), _(), ngettext("foo", "bar", 42)) }}') >>> list(extract_from_ast(node)) [(1, '_', 'foo'), (1, '_', ()), (1, 'ngettext', ('foo', 'bar', None))] >>> list(extract_from_ast(node, babel_style=False)) [(1, '_', ('foo',)), (1, 'ngettext', ('foo', 'bar'))] For every string found this function yields a ``(lineno, function, message)`` tuple, where: * ``lineno`` is the number of the line on which the string was found, * ``function`` is the name of the ``gettext`` function used (if the string was extracted from embedded Python code), and * ``message`` is the string itself (a ``unicode`` object, or a tuple of ``unicode`` objects for functions with multiple string arguments). This extraction function operates on the AST and is because of that unable to extract any comments. For comment support you have to use the babel extraction interface or extract comments yourself. """ for node in node.find_all(nodes.Call): if not isinstance(node.node, nodes.Name) or \ node.node.name not in gettext_functions: continue strings = [] for arg in node.args: if isinstance(arg, nodes.Const) and \ isinstance(arg.value, string_types): strings.append(arg.value) else: strings.append(None) for arg in node.kwargs: strings.append(None) if node.dyn_args is not None: strings.append(None) if node.dyn_kwargs is not None: strings.append(None) if not babel_style: strings = tuple(x for x in strings if x is not None) if not strings: continue else: if len(strings) == 1: strings = strings[0] else: strings = tuple(strings) yield node.lineno, node.node.name, strings class _CommentFinder(object): """Helper class to find comments in a token stream. Can only find comments for gettext calls forwards. Once the comment from line 4 is found, a comment for line 1 will not return a usable value. """ def __init__(self, tokens, comment_tags): self.tokens = tokens self.comment_tags = comment_tags self.offset = 0 self.last_lineno = 0 def find_backwards(self, offset): try: for _, token_type, token_value in \ reversed(self.tokens[self.offset:offset]): if token_type in ('comment', 'linecomment'): try: prefix, comment = token_value.split(None, 1) except ValueError: continue if prefix in self.comment_tags: return [comment.rstrip()] return [] finally: self.offset = offset def find_comments(self, lineno): if not self.comment_tags or self.last_lineno > lineno: return [] for idx, (token_lineno, _, _) in enumerate(self.tokens[self.offset:]): if token_lineno > lineno: return self.find_backwards(self.offset + idx) return self.find_backwards(len(self.tokens)) def babel_extract(fileobj, keywords, comment_tags, options): """Babel extraction method for Jinja templates. .. versionchanged:: 2.3 Basic support for translation comments was added. If `comment_tags` is now set to a list of keywords for extraction, the extractor will try to find the best preceeding comment that begins with one of the keywords. For best results, make sure to not have more than one gettext call in one line of code and the matching comment in the same line or the line before. .. versionchanged:: 2.5.1 The `newstyle_gettext` flag can be set to `True` to enable newstyle gettext calls. .. versionchanged:: 2.7 A `silent` option can now be provided. If set to `False` template syntax errors are propagated instead of being ignored. :param fileobj: the file-like object the messages should be extracted from :param keywords: a list of keywords (i.e. function names) that should be recognized as translation functions :param comment_tags: a list of translator tags to search for and include in the results. :param options: a dictionary of additional options (optional) :return: an iterator over ``(lineno, funcname, message, comments)`` tuples. (comments will be empty currently) """ extensions = set() for extension in options.get('extensions', '').split(','): extension = extension.strip() if not extension: continue extensions.add(import_string(extension)) if InternationalizationExtension not in extensions: extensions.add(InternationalizationExtension) def getbool(options, key, default=False): return options.get(key, str(default)).lower() in \ ('1', 'on', 'yes', 'true') silent = getbool(options, 'silent', True) environment = Environment( options.get('block_start_string', BLOCK_START_STRING), options.get('block_end_string', BLOCK_END_STRING), options.get('variable_start_string', VARIABLE_START_STRING), options.get('variable_end_string', VARIABLE_END_STRING), options.get('comment_start_string', COMMENT_START_STRING), options.get('comment_end_string', COMMENT_END_STRING), options.get('line_statement_prefix') or LINE_STATEMENT_PREFIX, options.get('line_comment_prefix') or LINE_COMMENT_PREFIX, getbool(options, 'trim_blocks', TRIM_BLOCKS), getbool(options, 'lstrip_blocks', LSTRIP_BLOCKS), NEWLINE_SEQUENCE, getbool(options, 'keep_trailing_newline', KEEP_TRAILING_NEWLINE), frozenset(extensions), cache_size=0, auto_reload=False ) if getbool(options, 'newstyle_gettext'): environment.newstyle_gettext = True source = fileobj.read().decode(options.get('encoding', 'utf-8')) try: node = environment.parse(source) tokens = list(environment.lex(environment.preprocess(source))) except TemplateSyntaxError as e: if not silent: raise # skip templates with syntax errors return finder = _CommentFinder(tokens, comment_tags) for lineno, func, message in extract_from_ast(node, keywords): yield lineno, func, message, finder.find_comments(lineno) #: nicer import names i18n = InternationalizationExtension do = ExprStmtExtension loopcontrols = LoopControlExtension with_ = WithExtension autoescape = AutoEscapeExtension