mako/parsetree.py

# mako/parsetree.py
# Copyright 2006-2019 the Mako authors and contributors <see AUTHORS file>
#
# This module is part of Mako and is released under
# the MIT License: http://www.opensource.org/licenses/mit-license.php

"""defines the parse tree components for Mako templates."""

import re

from mako import ast
from mako import compat
from mako import exceptions
from mako import filters
from mako import util


class Node(object):

    """base class for a Node in the parse tree."""

    def __init__(self, source, lineno, pos, filename):
        self.source = source
        self.lineno = lineno
        self.pos = pos
        self.filename = filename

    @property
    def exception_kwargs(self):
        return {
            "source": self.source,
            "lineno": self.lineno,
            "pos": self.pos,
            "filename": self.filename,
        }

    def get_children(self):
        return []

    def accept_visitor(self, visitor):
        def traverse(node):
            for n in node.get_children():
                n.accept_visitor(visitor)

        method = getattr(visitor, "visit" + self.__class__.__name__, traverse)
        method(self)


class TemplateNode(Node):

    """a 'container' node that stores the overall collection of nodes."""

    def __init__(self, filename):
        super(TemplateNode, self).__init__("", 0, 0, filename)
        self.nodes = []
        self.page_attributes = {}

    def get_children(self):
        return self.nodes

    def __repr__(self):
        return "TemplateNode(%s, %r)" % (
            util.sorted_dict_repr(self.page_attributes),
            self.nodes,
        )


class ControlLine(Node):

    """defines a control line, a line-oriented python line or end tag.

    e.g.::

        % if foo:
            (markup)
        % endif

    """

    has_loop_context = False

    def __init__(self, keyword, isend, text, **kwargs):
        super(ControlLine, self).__init__(**kwargs)
        self.text = text
        self.keyword = keyword
        self.isend = isend
        self.is_primary = keyword in ["for", "if", "while", "try", "with"]
        self.nodes = []
        if self.isend:
            self._declared_identifiers = []
            self._undeclared_identifiers = []
        else:
            code = ast.PythonFragment(text, **self.exception_kwargs)
            self._declared_identifiers = code.declared_identifiers
            self._undeclared_identifiers = code.undeclared_identifiers

    def get_children(self):
        return self.nodes

    def declared_identifiers(self):
        return self._declared_identifiers

    def undeclared_identifiers(self):
        return self._undeclared_identifiers

    def is_ternary(self, keyword):
        """return true if the given keyword is a ternary keyword
        for this ControlLine"""

        return keyword in {
            "if": set(["else", "elif"]),
            "try": set(["except", "finally"]),
            "for": set(["else"]),
        }.get(self.keyword, [])

    def __repr__(self):
        return "ControlLine(%r, %r, %r, %r)" % (
            self.keyword,
            self.text,
            self.isend,
            (self.lineno, self.pos),
        )


class Text(Node):

    """defines plain text in the template."""

    def __init__(self, content, **kwargs):
        super(Text, self).__init__(**kwargs)
        self.content = content

    def __repr__(self):
        return "Text(%r, %r)" % (self.content, (self.lineno, self.pos))


class Code(Node):

    """defines a Python code block, either inline or module level.

    e.g.::

        inline:
        <%
            x = 12
        %>

        module level:
        <%!
            import logger
        %>

    """

    def __init__(self, text, ismodule, **kwargs):
        super(Code, self).__init__(**kwargs)
        self.text = text
        self.ismodule = ismodule
        self.code = ast.PythonCode(text, **self.exception_kwargs)

    def declared_identifiers(self):
        return self.code.declared_identifiers

    def undeclared_identifiers(self):
        return self.code.undeclared_identifiers

    def __repr__(self):
        return "Code(%r, %r, %r)" % (
            self.text,
            self.ismodule,
            (self.lineno, self.pos),
        )


class Comment(Node):

    """defines a comment line.

    # this is a comment

    """

    def __init__(self, text, **kwargs):
        super(Comment, self).__init__(**kwargs)
        self.text = text

    def __repr__(self):
        return "Comment(%r, %r)" % (self.text, (self.lineno, self.pos))


class Expression(Node):

    """defines an inline expression.

    ${x+y}

    """

    def __init__(self, text, escapes, **kwargs):
        super(Expression, self).__init__(**kwargs)
        self.text = text
        self.escapes = escapes
        self.escapes_code = ast.ArgumentList(escapes, **self.exception_kwargs)
        self.code = ast.PythonCode(text, **self.exception_kwargs)

    def declared_identifiers(self):
        return []

    def undeclared_identifiers(self):
        # TODO: make the "filter" shortcut list configurable at parse/gen time
        return self.code.undeclared_identifiers.union(
            self.escapes_code.undeclared_identifiers.difference(
                set(filters.DEFAULT_ESCAPES.keys())
            )
        ).difference(self.code.declared_identifiers)

    def __repr__(self):
        return "Expression(%r, %r, %r)" % (
            self.text,
            self.escapes_code.args,
            (self.lineno, self.pos),
        )


class _TagMeta(type):

    """metaclass to allow Tag to produce a subclass according to
    its keyword"""

    _classmap = {}

    def __init__(cls, clsname, bases, dict_):
        if getattr(cls, "__keyword__", None) is not None:
            cls._classmap[cls.__keyword__] = cls
        super(_TagMeta, cls).__init__(clsname, bases, dict_)

    def __call__(cls, keyword, attributes, **kwargs):
        if ":" in keyword:
            ns, defname = keyword.split(":")
            return type.__call__(
                CallNamespaceTag, ns, defname, attributes, **kwargs
            )

        try:
            cls = _TagMeta._classmap[keyword]
        except KeyError:
            raise exceptions.CompileException(
                "No such tag: '%s'" % keyword,
                source=kwargs["source"],
                lineno=kwargs["lineno"],
                pos=kwargs["pos"],
                filename=kwargs["filename"],
            )
        return type.__call__(cls, keyword, attributes, **kwargs)


class Tag(compat.with_metaclass(_TagMeta, Node)):
    """abstract base class for tags.

    e.g.::

        <%sometag/>

        <%someothertag>
            stuff
        </%someothertag>

    """

    __keyword__ = None

    def __init__(
        self,
        keyword,
        attributes,
        expressions,
        nonexpressions,
        required,
        **kwargs
    ):
        r"""construct a new Tag instance.

        this constructor not called directly, and is only called
        by subclasses.

        :param keyword: the tag keyword

        :param attributes: raw dictionary of attribute key/value pairs

        :param expressions: a set of identifiers that are legal attributes,
         which can also contain embedded expressions

        :param nonexpressions: a set of identifiers that are legal
         attributes, which cannot contain embedded expressions

        :param \**kwargs:
         other arguments passed to the Node superclass (lineno, pos)

        """
        super(Tag, self).__init__(**kwargs)
        self.keyword = keyword
        self.attributes = attributes
        self._parse_attributes(expressions, nonexpressions)
        missing = [r for r in required if r not in self.parsed_attributes]
        if len(missing):
            raise exceptions.CompileException(
                "Missing attribute(s): %s"
                % ",".join([repr(m) for m in missing]),
                **self.exception_kwargs
            )
        self.parent = None
        self.nodes = []

    def is_root(self):
        return self.parent is None

    def get_children(self):
        return self.nodes

    def _parse_attributes(self, expressions, nonexpressions):
        undeclared_identifiers = set()
        self.parsed_attributes = {}
        for key in self.attributes:
            if key in expressions:
                expr = []
                for x in re.compile(r"(\${.+?})", re.S).split(
                    self.attributes[key]
                ):
                    m = re.compile(r"^\${(.+?)}$", re.S).match(x)
                    if m:
                        code = ast.PythonCode(
                            m.group(1).rstrip(), **self.exception_kwargs
                        )
                        # we aren't discarding "declared_identifiers" here,
                        # which we do so that list comprehension-declared
                        # variables aren't counted.   As yet can't find a
                        # condition that requires it here.
                        undeclared_identifiers = undeclared_identifiers.union(
                            code.undeclared_identifiers
                        )
                        expr.append("(%s)" % m.group(1))
                    else:
                        if x:
                            expr.append(repr(x))
                self.parsed_attributes[key] = " + ".join(expr) or repr("")
            elif key in nonexpressions:
                if re.search(r"\${.+?}", self.attributes[key]):
                    raise exceptions.CompileException(
                        "Attibute '%s' in tag '%s' does not allow embedded "
                        "expressions" % (key, self.keyword),
                        **self.exception_kwargs
                    )
                self.parsed_attributes[key] = repr(self.attributes[key])
            else:
                raise exceptions.CompileException(
                    "Invalid attribute for tag '%s': '%s'"
                    % (self.keyword, key),
                    **self.exception_kwargs
                )
        self.expression_undeclared_identifiers = undeclared_identifiers

    def declared_identifiers(self):
        return []

    def undeclared_identifiers(self):
        return self.expression_undeclared_identifiers

    def __repr__(self):
        return "%s(%r, %s, %r, %r)" % (
            self.__class__.__name__,
            self.keyword,
            util.sorted_dict_repr(self.attributes),
            (self.lineno, self.pos),
            self.nodes,
        )


class IncludeTag(Tag):
    __keyword__ = "include"

    def __init__(self, keyword, attributes, **kwargs):
        super(IncludeTag, self).__init__(
            keyword,
            attributes,
            ("file", "import", "args"),
            (),
            ("file",),
            **kwargs
        )
        self.page_args = ast.PythonCode(
            "__DUMMY(%s)" % attributes.get("args", ""), **self.exception_kwargs
        )

    def declared_identifiers(self):
        return []

    def undeclared_identifiers(self):
        identifiers = self.page_args.undeclared_identifiers.difference(
            set(["__DUMMY"])
        ).difference(self.page_args.declared_identifiers)
        return identifiers.union(
            super(IncludeTag, self).undeclared_identifiers()
        )


class NamespaceTag(Tag):
    __keyword__ = "namespace"

    def __init__(self, keyword, attributes, **kwargs):
        super(NamespaceTag, self).__init__(
            keyword,
            attributes,
            ("file",),
            ("name", "inheritable", "import", "module"),
            (),
            **kwargs
        )

        self.name = attributes.get("name", "__anon_%s" % hex(abs(id(self))))
        if "name" not in attributes and "import" not in attributes:
            raise exceptions.CompileException(
                "'name' and/or 'import' attributes are required "
                "for <%namespace>",
                **self.exception_kwargs
            )
        if "file" in attributes and "module" in attributes:
            raise exceptions.CompileException(
                "<%namespace> may only have one of 'file' or 'module'",
                **self.exception_kwargs
            )

    def declared_identifiers(self):
        return []


class TextTag(Tag):
    __keyword__ = "text"

    def __init__(self, keyword, attributes, **kwargs):
        super(TextTag, self).__init__(
            keyword, attributes, (), ("filter"), (), **kwargs
        )
        self.filter_args = ast.ArgumentList(
            attributes.get("filter", ""), **self.exception_kwargs
        )

    def undeclared_identifiers(self):
        return self.filter_args.undeclared_identifiers.difference(
            filters.DEFAULT_ESCAPES.keys()
        ).union(self.expression_undeclared_identifiers)


class DefTag(Tag):
    __keyword__ = "def"

    def __init__(self, keyword, attributes, **kwargs):
        expressions = ["buffered", "cached"] + [
            c for c in attributes if c.startswith("cache_")
        ]

        super(DefTag, self).__init__(
            keyword,
            attributes,
            expressions,
            ("name", "filter", "decorator"),
            ("name",),
            **kwargs
        )
        name = attributes["name"]
        if re.match(r"^[\w_]+$", name):
            raise exceptions.CompileException(
                "Missing parenthesis in %def", **self.exception_kwargs
            )
        self.function_decl = ast.FunctionDecl(
            "def " + name + ":pass", **self.exception_kwargs
        )
        self.name = self.function_decl.funcname
        self.decorator = attributes.get("decorator", "")
        self.filter_args = ast.ArgumentList(
            attributes.get("filter", ""), **self.exception_kwargs
        )

    is_anonymous = False
    is_block = False

    @property
    def funcname(self):
        return self.function_decl.funcname

    def get_argument_expressions(self, **kw):
        return self.function_decl.get_argument_expressions(**kw)

    def declared_identifiers(self):
        return self.function_decl.allargnames

    def undeclared_identifiers(self):
        res = []
        for c in self.function_decl.defaults:
            res += list(
                ast.PythonCode(
                    c, **self.exception_kwargs
                ).undeclared_identifiers
            )
        return (
            set(res)
            .union(
                self.filter_args.undeclared_identifiers.difference(
                    filters.DEFAULT_ESCAPES.keys()
                )
            )
            .union(self.expression_undeclared_identifiers)
            .difference(self.function_decl.allargnames)
        )


class BlockTag(Tag):
    __keyword__ = "block"

    def __init__(self, keyword, attributes, **kwargs):
        expressions = ["buffered", "cached", "args"] + [
            c for c in attributes if c.startswith("cache_")
        ]

        super(BlockTag, self).__init__(
            keyword,
            attributes,
            expressions,
            ("name", "filter", "decorator"),
            (),
            **kwargs
        )
        name = attributes.get("name")
        if name and not re.match(r"^[\w_]+$", name):
            raise exceptions.CompileException(
                "%block may not specify an argument signature",
                **self.exception_kwargs
            )
        if not name and attributes.get("args", None):
            raise exceptions.CompileException(
                "Only named %blocks may specify args", **self.exception_kwargs
            )
        self.body_decl = ast.FunctionArgs(
            attributes.get("args", ""), **self.exception_kwargs
        )

        self.name = name
        self.decorator = attributes.get("decorator", "")
        self.filter_args = ast.ArgumentList(
            attributes.get("filter", ""), **self.exception_kwargs
        )

    is_block = True

    @property
    def is_anonymous(self):
        return self.name is None

    @property
    def funcname(self):
        return self.name or "__M_anon_%d" % (self.lineno,)

    def get_argument_expressions(self, **kw):
        return self.body_decl.get_argument_expressions(**kw)

    def declared_identifiers(self):
        return self.body_decl.allargnames

    def undeclared_identifiers(self):
        return (
            self.filter_args.undeclared_identifiers.difference(
                filters.DEFAULT_ESCAPES.keys()
            )
        ).union(self.expression_undeclared_identifiers)


class CallTag(Tag):
    __keyword__ = "call"

    def __init__(self, keyword, attributes, **kwargs):
        super(CallTag, self).__init__(
            keyword, attributes, ("args"), ("expr",), ("expr",), **kwargs
        )
        self.expression = attributes["expr"]
        self.code = ast.PythonCode(self.expression, **self.exception_kwargs)
        self.body_decl = ast.FunctionArgs(
            attributes.get("args", ""), **self.exception_kwargs
        )

    def declared_identifiers(self):
        return self.code.declared_identifiers.union(self.body_decl.allargnames)

    def undeclared_identifiers(self):
        return self.code.undeclared_identifiers.difference(
            self.code.declared_identifiers
        )


class CallNamespaceTag(Tag):
    def __init__(self, namespace, defname, attributes, **kwargs):
        super(CallNamespaceTag, self).__init__(
            namespace + ":" + defname,
            attributes,
            tuple(attributes.keys()) + ("args",),
            (),
            (),
            **kwargs
        )

        self.expression = "%s.%s(%s)" % (
            namespace,
            defname,
            ",".join(
                [
                    "%s=%s" % (k, v)
                    for k, v in self.parsed_attributes.items()
                    if k != "args"
                ]
            ),
        )
        self.code = ast.PythonCode(self.expression, **self.exception_kwargs)
        self.body_decl = ast.FunctionArgs(
            attributes.get("args", ""), **self.exception_kwargs
        )

    def declared_identifiers(self):
        return self.code.declared_identifiers.union(self.body_decl.allargnames)

    def undeclared_identifiers(self):
        return self.code.undeclared_identifiers.difference(
            self.code.declared_identifiers
        )


class InheritTag(Tag):
    __keyword__ = "inherit"

    def __init__(self, keyword, attributes, **kwargs):
        super(InheritTag, self).__init__(
            keyword, attributes, ("file",), (), ("file",), **kwargs
        )


class PageTag(Tag):
    __keyword__ = "page"

    def __init__(self, keyword, attributes, **kwargs):
        expressions = [
            "cached",
            "args",
            "expression_filter",
            "enable_loop",
        ] + [c for c in attributes if c.startswith("cache_")]

        super(PageTag, self).__init__(
            keyword, attributes, expressions, (), (), **kwargs
        )
        self.body_decl = ast.FunctionArgs(
            attributes.get("args", ""), **self.exception_kwargs
        )
        self.filter_args = ast.ArgumentList(
            attributes.get("expression_filter", ""), **self.exception_kwargs
        )

    def declared_identifiers(self):
        return self.body_decl.allargnames