# Use of this source code is governed by a BSD-style license that can be

# found in the LICENSE file.

__license__ = "MIT"

try:

    from collections.abc import Callable # Python 3.6

except ImportError as e:

    from collections import Callable

import re

import shlex

import sys

import warnings

from bs4.dammit import EntitySubstitution

DEFAULT_OUTPUT_ENCODING = "utf-8"

PY3K = (sys.version_info[0] > 2)

whitespace_re = re.compile(r"\s+")

def _alias(attr):

    """Alias one attribute name to another for backward compatibility"""

    @property

    def alias(self):

        return getattr(self, attr)

    @alias.setter

    def alias(self):

        return setattr(self, attr)

    return alias

class NamespacedAttribute(str):

    def __new__(cls, prefix, name, namespace=None):

        if name is None:

            obj = str.__new__(cls, prefix)

        elif prefix is None:

            # Not really namespaced.

            obj = str.__new__(cls, name)

        else:

            obj = str.__new__(cls, prefix + ":" + name)

        obj.prefix = prefix

        obj.name = name

        obj.namespace = namespace

        return obj

class AttributeValueWithCharsetSubstitution(str):

    """A stand-in object for a character encoding specified in HTML."""

class CharsetMetaAttributeValue(AttributeValueWithCharsetSubstitution):

    """A generic stand-in for the value of a meta tag's 'charset' attribute.

    When Beautiful Soup parses the markup '<meta charset="utf8">', the

    value of the 'charset' attribute will be one of these objects.

    """

    def __new__(cls, original_value):

        obj = str.__new__(cls, original_value)

        obj.original_value = original_value

        return obj

    def encode(self, encoding):

        return encoding

class ContentMetaAttributeValue(AttributeValueWithCharsetSubstitution):

    """A generic stand-in for the value of a meta tag's 'content' attribute.

    When Beautiful Soup parses the markup:

     <meta http-equiv="content-type" content="text/html; charset=utf8">

    The value of the 'content' attribute will be one of these objects.

    """

    CHARSET_RE = re.compile(r"((^|;)\s*charset=)([^;]*)", re.M)

    def __new__(cls, original_value):

        match = cls.CHARSET_RE.search(original_value)

        if match is None:

            # No substitution necessary.

            return str.__new__(str, original_value)

        obj = str.__new__(cls, original_value)

        obj.original_value = original_value

        return obj

    def encode(self, encoding):

        def rewrite(match):

            return match.group(1) + encoding

        return self.CHARSET_RE.sub(rewrite, self.original_value)

class HTMLAwareEntitySubstitution(EntitySubstitution):

    """Entity substitution rules that are aware of some HTML quirks.

    Specifically, the contents of <script> and <style> tags should not

    undergo entity substitution.

    Incoming NavigableString objects are checked to see if they're the

    direct children of a <script> or <style> tag.

    """

    cdata_containing_tags = set(["script", "style"])

    preformatted_tags = set(["pre"])

    preserve_whitespace_tags = set(['pre', 'textarea'])

    @classmethod

    def _substitute_if_appropriate(cls, ns, f):

        if (isinstance(ns, NavigableString)

            and ns.parent is not None

            and ns.parent.name in cls.cdata_containing_tags):

            # Do nothing.

            return ns

        # Substitute.

        return f(ns)

    @classmethod

    def substitute_html(cls, ns):

        return cls._substitute_if_appropriate(

            ns, EntitySubstitution.substitute_html)

    @classmethod

    def substitute_xml(cls, ns):

        return cls._substitute_if_appropriate(

            ns, EntitySubstitution.substitute_xml)

class Formatter(object):

    """Contains information about how to format a parse tree."""

    # By default, represent void elements as <tag/> rather than <tag>

    void_element_close_prefix = '/'

    def substitute_entities(self, *args, **kwargs):

        """Transform certain characters into named entities."""

        raise NotImplementedError()

class HTMLFormatter(Formatter):

    """The default HTML formatter."""

    def substitute(self, *args, **kwargs):

        return HTMLAwareEntitySubstitution.substitute_html(*args, **kwargs)

class MinimalHTMLFormatter(Formatter):

    """A minimal HTML formatter."""

    def substitute(self, *args, **kwargs):

        return HTMLAwareEntitySubstitution.substitute_xml(*args, **kwargs)

class HTML5Formatter(HTMLFormatter):

    """An HTML formatter that omits the slash in a void tag."""

    void_element_close_prefix = None

class XMLFormatter(Formatter):

    """Substitute only the essential XML entities."""

    def substitute(self, *args, **kwargs):

        return EntitySubstitution.substitute_xml(*args, **kwargs)

class HTMLXMLFormatter(Formatter):

    """Format XML using HTML rules."""

    def substitute(self, *args, **kwargs):

        return HTMLAwareEntitySubstitution.substitute_html(*args, **kwargs)

class PageElement(object):

    """Contains the navigational information for some part of the page

    (either a tag or a piece of text)"""

    # There are five possible values for the "formatter" argument passed in

    # to methods like encode() and prettify():

    #

    # "html" - All Unicode characters with corresponding HTML entities

    #   are converted to those entities on output.

    # "html5" - The same as "html", but empty void tags are represented as

    #   <tag> rather than <tag/>

    # "minimal" - Bare ampersands and angle brackets are converted to

    #   XML entities: &amp; &lt; &gt;

    # None - The null formatter. Unicode characters are never

    #   converted to entities.  This is not recommended, but it's

    #   faster than "minimal".

    # A callable function - it will be called on every string that needs to undergo entity substitution.

    # A Formatter instance - Formatter.substitute(string) will be called on every string that

    #  needs to undergo entity substitution.

    #

    # In an HTML document, the default "html", "html5", and "minimal"

    # functions will leave the contents of <script> and <style> tags

    # alone. For an XML document, all tags will be given the same

    # treatment.

    HTML_FORMATTERS = {

        "html" : HTMLFormatter(),

        "html5" : HTML5Formatter(),

        "minimal" : MinimalHTMLFormatter(),

        None : None

        }

    XML_FORMATTERS = {

        "html" : HTMLXMLFormatter(),

        "minimal" : XMLFormatter(),

        None : None

        }

    def format_string(self, s, formatter='minimal'):

        """Format the given string using the given formatter."""

        if isinstance(formatter, str):

            formatter = self._formatter_for_name(formatter)

        if formatter is None:

            output = s

        else:

            if callable(formatter):

                # Backwards compatibility -- you used to pass in a formatting method.

                output = formatter(s)

            else:

                output = formatter.substitute(s)

        return output

    @property

    def _is_xml(self):

        """Is this element part of an XML tree or an HTML tree?

        This is used when mapping a formatter name ("minimal") to an

        appropriate function (one that performs entity-substitution on

        the contents of <script> and <style> tags, or not). It can be

        inefficient, but it should be called very rarely.

        """

        if self.known_xml is not None:

            # Most of the time we will have determined this when the

            # document is parsed.

            return self.known_xml

        # Otherwise, it's likely that this element was created by

        # direct invocation of the constructor from within the user's

        # Python code.

        if self.parent is None:

            # This is the top-level object. It should have .known_xml set

            # from tree creation. If not, take a guess--BS is usually

            # used on HTML markup.

            return getattr(self, 'is_xml', False)

        return self.parent._is_xml

    def _formatter_for_name(self, name):

        "Look up a formatter function based on its name and the tree."

        if self._is_xml:

            return self.XML_FORMATTERS.get(name, XMLFormatter())

        else:

            return self.HTML_FORMATTERS.get(name, HTMLFormatter())

    def setup(self, parent=None, previous_element=None, next_element=None,

              previous_sibling=None, next_sibling=None):

        """Sets up the initial relations between this element and

        other elements."""

        self.parent = parent

        self.previous_element = previous_element

        if previous_element is not None:

            self.previous_element.next_element = self

        self.next_element = next_element

        if self.next_element:

            self.next_element.previous_element = self

        self.next_sibling = next_sibling

        if self.next_sibling:

            self.next_sibling.previous_sibling = self

        if (not previous_sibling

            and self.parent is not None and self.parent.contents):

            previous_sibling = self.parent.contents[-1]

        self.previous_sibling = previous_sibling

        if previous_sibling:

            self.previous_sibling.next_sibling = self

    nextSibling = _alias("next_sibling")  # BS3

    previousSibling = _alias("previous_sibling")  # BS3

    def replace_with(self, replace_with):

        if not self.parent:

            raise ValueError(

                "Cannot replace one element with another when the"

                "element to be replaced is not part of a tree.")

        if replace_with is self:

            return

        if replace_with is self.parent:

            raise ValueError("Cannot replace a Tag with its parent.")

        old_parent = self.parent

        my_index = self.parent.index(self)

        self.extract()

        old_parent.insert(my_index, replace_with)

        return self

    replaceWith = replace_with  # BS3

    def unwrap(self):

        my_parent = self.parent

        if not self.parent:

            raise ValueError(

                "Cannot replace an element with its contents when that"

                "element is not part of a tree.")

        my_index = self.parent.index(self)

        self.extract()

        for child in reversed(self.contents[:]):

            my_parent.insert(my_index, child)

        return self

    replace_with_children = unwrap

    replaceWithChildren = unwrap  # BS3

    def wrap(self, wrap_inside):

        me = self.replace_with(wrap_inside)

        wrap_inside.append(me)

        return wrap_inside

    def extract(self):

        """Destructively rips this element out of the tree."""

        if self.parent is not None:

            del self.parent.contents[self.parent.index(self)]

        #Find the two elements that would be next to each other if

        #this element (and any children) hadn't been parsed. Connect

        #the two.

        last_child = self._last_descendant()

        next_element = last_child.next_element

        if (self.previous_element is not None and

            self.previous_element is not next_element):

            self.previous_element.next_element = next_element

        if next_element is not None and next_element is not self.previous_element:

            next_element.previous_element = self.previous_element

        self.previous_element = None

        last_child.next_element = None

        self.parent = None

        if (self.previous_sibling is not None

            and self.previous_sibling is not self.next_sibling):

            self.previous_sibling.next_sibling = self.next_sibling

        if (self.next_sibling is not None

            and self.next_sibling is not self.previous_sibling):

            self.next_sibling.previous_sibling = self.previous_sibling

        self.previous_sibling = self.next_sibling = None

        return self

    def _last_descendant(self, is_initialized=True, accept_self=True):

        "Finds the last element beneath this object to be parsed."

        if is_initialized and self.next_sibling:

            last_child = self.next_sibling.previous_element

        else:

            last_child = self

            while isinstance(last_child, Tag) and last_child.contents:

                last_child = last_child.contents[-1]

        if not accept_self and last_child is self:

            last_child = None

        return last_child

    # BS3: Not part of the API!

    _lastRecursiveChild = _last_descendant

    def insert(self, position, new_child):

        if new_child is None:

            raise ValueError("Cannot insert None into a tag.")

        if new_child is self:

            raise ValueError("Cannot insert a tag into itself.")

        if (isinstance(new_child, str)

            and not isinstance(new_child, NavigableString)):

            new_child = NavigableString(new_child)

        from bs4 import BeautifulSoup

        if isinstance(new_child, BeautifulSoup):

            # We don't want to end up with a situation where one BeautifulSoup

            # object contains another. Insert the children one at a time.

            for subchild in list(new_child.contents):

                self.insert(position, subchild)

                position += 1

            return

        position = min(position, len(self.contents))

        if hasattr(new_child, 'parent') and new_child.parent is not None:

            # We're 'inserting' an element that's already one

            # of this object's children.

            if new_child.parent is self:

                current_index = self.index(new_child)

                if current_index < position:

                    # We're moving this element further down the list

                    # of this object's children. That means that when

                    # we extract this element, our target index will

                    # jump down one.

                    position -= 1

            new_child.extract()

        new_child.parent = self

        previous_child = None

        if position == 0:

            new_child.previous_sibling = None

            new_child.previous_element = self

        else:

            previous_child = self.contents[position - 1]

            new_child.previous_sibling = previous_child

            new_child.previous_sibling.next_sibling = new_child

            new_child.previous_element = previous_child._last_descendant(False)

        if new_child.previous_element is not None:

            new_child.previous_element.next_element = new_child

        new_childs_last_element = new_child._last_descendant(False)

        if position >= len(self.contents):

            new_child.next_sibling = None

            parent = self

            parents_next_sibling = None

            while parents_next_sibling is None and parent is not None:

                parents_next_sibling = parent.next_sibling

                parent = parent.parent

                if parents_next_sibling is not None:

                    # We found the element that comes next in the document.

                    break

            if parents_next_sibling is not None:

                new_childs_last_element.next_element = parents_next_sibling

            else:

                # The last element of this tag is the last element in

                # the document.

                new_childs_last_element.next_element = None

        else:

            next_child = self.contents[position]

            new_child.next_sibling = next_child

            if new_child.next_sibling is not None:

                new_child.next_sibling.previous_sibling = new_child

            new_childs_last_element.next_element = next_child

        if new_childs_last_element.next_element is not None:

            new_childs_last_element.next_element.previous_element = new_childs_last_element

        self.contents.insert(position, new_child)

    def append(self, tag):

        """Appends the given tag to the contents of this tag."""

        self.insert(len(self.contents), tag)

    def insert_before(self, predecessor):

        """Makes the given element the immediate predecessor of this one.

        The two elements will have the same parent, and the given element

        will be immediately before this one.

        """

        if self is predecessor:

            raise ValueError("Can't insert an element before itself.")

        parent = self.parent

        if parent is None:

            raise ValueError(

                "Element has no parent, so 'before' has no meaning.")

        # Extract first so that the index won't be screwed up if they

        # are siblings.

        if isinstance(predecessor, PageElement):

            predecessor.extract()

        index = parent.index(self)

        parent.insert(index, predecessor)

    def insert_after(self, successor):

        """Makes the given element the immediate successor of this one.

        The two elements will have the same parent, and the given element

        will be immediately after this one.

        """

        if self is successor:

            raise ValueError("Can't insert an element after itself.")

        parent = self.parent

        if parent is None:

            raise ValueError(

                "Element has no parent, so 'after' has no meaning.")

        # Extract first so that the index won't be screwed up if they

        # are siblings.

        if isinstance(successor, PageElement):

            successor.extract()

        index = parent.index(self)

        parent.insert(index+1, successor)

    def find_next(self, name=None, attrs={}, text=None, **kwargs):

        """Returns the first item that matches the given criteria and

        appears after this Tag in the document."""

        return self._find_one(self.find_all_next, name, attrs, text, **kwargs)

    findNext = find_next  # BS3

    def find_all_next(self, name=None, attrs={}, text=None, limit=None,

                    **kwargs):

        """Returns all items that match the given criteria and appear

        after this Tag in the document."""

        return self._find_all(name, attrs, text, limit, self.next_elements,

                             **kwargs)

    findAllNext = find_all_next  # BS3

    def find_next_sibling(self, name=None, attrs={}, text=None, **kwargs):

        """Returns the closest sibling to this Tag that matches the

        given criteria and appears after this Tag in the document."""

        return self._find_one(self.find_next_siblings, name, attrs, text,

                             **kwargs)

    findNextSibling = find_next_sibling  # BS3

    def find_next_siblings(self, name=None, attrs={}, text=None, limit=None,

                           **kwargs):

        """Returns the siblings of this Tag that match the given

        criteria and appear after this Tag in the document."""

        return self._find_all(name, attrs, text, limit,

                              self.next_siblings, **kwargs)

    findNextSiblings = find_next_siblings   # BS3

    fetchNextSiblings = find_next_siblings  # BS2

    def find_previous(self, name=None, attrs={}, text=None, **kwargs):

        """Returns the first item that matches the given criteria and

        appears before this Tag in the document."""

        return self._find_one(

            self.find_all_previous, name, attrs, text, **kwargs)

    findPrevious = find_previous  # BS3

    def find_all_previous(self, name=None, attrs={}, text=None, limit=None,

                        **kwargs):

        """Returns all items that match the given criteria and appear

        before this Tag in the document."""

        return self._find_all(name, attrs, text, limit, self.previous_elements,

                           **kwargs)

    findAllPrevious = find_all_previous  # BS3

    fetchPrevious = find_all_previous    # BS2

    def find_previous_sibling(self, name=None, attrs={}, text=None, **kwargs):

        """Returns the closest sibling to this Tag that matches the

        given criteria and appears before this Tag in the document."""

        return self._find_one(self.find_previous_siblings, name, attrs, text,

                             **kwargs)

    findPreviousSibling = find_previous_sibling  # BS3

    def find_previous_siblings(self, name=None, attrs={}, text=None,

                               limit=None, **kwargs):

        """Returns the siblings of this Tag that match the given

        criteria and appear before this Tag in the document."""

        return self._find_all(name, attrs, text, limit,

                              self.previous_siblings, **kwargs)

    findPreviousSiblings = find_previous_siblings   # BS3

    fetchPreviousSiblings = find_previous_siblings  # BS2

    def find_parent(self, name=None, attrs={}, **kwargs):

        """Returns the closest parent of this Tag that matches the given

        criteria."""

        # NOTE: We can't use _find_one because findParents takes a different

        # set of arguments.

        r = None

        l = self.find_parents(name, attrs, 1, **kwargs)

        if l:

            r = l[0]

        return r

    findParent = find_parent  # BS3

    def find_parents(self, name=None, attrs={}, limit=None, **kwargs):

        """Returns the parents of this Tag that match the given

        criteria."""

        return self._find_all(name, attrs, None, limit, self.parents,

                             **kwargs)

    findParents = find_parents   # BS3

    fetchParents = find_parents  # BS2

    @property

    def next(self):

        return self.next_element

    @property

    def previous(self):

        return self.previous_element

    #These methods do the real heavy lifting.

    def _find_one(self, method, name, attrs, text, **kwargs):

        r = None

        l = method(name, attrs, text, 1, **kwargs)

        if l:

            r = l[0]

        return r

    def _find_all(self, name, attrs, text, limit, generator, **kwargs):

        "Iterates over a generator looking for things that match."

        if text is None and 'string' in kwargs:

            text = kwargs['string']

            del kwargs['string']

        if isinstance(name, SoupStrainer):

            strainer = name

        else:

            strainer = SoupStrainer(name, attrs, text, **kwargs)

        if text is None and not limit and not attrs and not kwargs:

            if name is True or name is None:

                # Optimization to find all tags.

                result = (element for element in generator

                          if isinstance(element, Tag))

                return ResultSet(strainer, result)

            elif isinstance(name, str):

                # Optimization to find all tags with a given name.

                if name.count(':') == 1:

                    # This is a name with a prefix. If this is a namespace-aware document,

                    # we need to match the local name against tag.name. If not,

                    # we need to match the fully-qualified name against tag.name.

                    prefix, local_name = name.split(':', 1)

                else:

                    prefix = None

                    local_name = name

                result = (element for element in generator

                          if isinstance(element, Tag)

                          and (

                              element.name == name

                          ) or (

                              element.name == local_name

                              and (prefix is None or element.prefix == prefix)

                          )

                )

                return ResultSet(strainer, result)

        results = ResultSet(strainer)

        while True:

            try:

                i = next(generator)

            except StopIteration:

                break

            if i:

                found = strainer.search(i)

                if found:

                    results.append(found)

                    if limit and len(results) >= limit:

                        break

        return results

    #These generators can be used to navigate starting from both

    #NavigableStrings and Tags.

    @property

    def next_elements(self):

        i = self.next_element

        while i is not None:

            yield i

            i = i.next_element

    @property

    def next_siblings(self):

        i = self.next_sibling

        while i is not None:

            yield i

            i = i.next_sibling

    @property

    def previous_elements(self):

        i = self.previous_element

        while i is not None:

            yield i

            i = i.previous_element

    @property

    def previous_siblings(self):

        i = self.previous_sibling

        while i is not None:

            yield i

            i = i.previous_sibling

    @property

    def parents(self):

        i = self.parent

        while i is not None:

            yield i

            i = i.parent

    # Methods for supporting CSS selectors.

    tag_name_re = re.compile('^[a-zA-Z0-9][-.a-zA-Z0-9:_]*$')

    # /^([a-zA-Z0-9][-.a-zA-Z0-9:_]*)\[(\w+)([=~\|\^\$\*]?)=?"?([^\]"]*)"?\]$/

    #   \---------------------------/  \---/\-------------/    \-------/

    #     |                              |         |               |

    #     |                              |         |           The value

    #     |                              |    ~,|,^,$,* or =

    #     |                           Attribute

    #    Tag

    attribselect_re = re.compile(

        r'^(?P<tag>[a-zA-Z0-9][-.a-zA-Z0-9:_]*)?\[(?P<attribute>[\w-]+)(?P<operator>[=~\|\^\$\*]?)' +

        r'=?"?(?P<value>[^\]"]*)"?\]$'

        )

    def _attr_value_as_string(self, value, default=None):

        """Force an attribute value into a string representation.

        A multi-valued attribute will be converted into a

        space-separated stirng.

        """

        value = self.get(value, default)

        if isinstance(value, list) or isinstance(value, tuple):

            value =" ".join(value)

        return value

    def _tag_name_matches_and(self, function, tag_name):

        if not tag_name:

            return function

        else:

            def _match(tag):

                return tag.name == tag_name and function(tag)

            return _match

    def _attribute_checker(self, operator, attribute, value=''):

        """Create a function that performs a CSS selector operation.

        Takes an operator, attribute and optional value. Returns a

        function that will return True for elements that match that

        combination.

        """

        if operator == '=':

            # string representation of `attribute` is equal to `value`

            return lambda el: el._attr_value_as_string(attribute) == value

        elif operator == '~':

            # space-separated list representation of `attribute`

            # contains `value`

            def _includes_value(element):

                attribute_value = element.get(attribute, [])

                if not isinstance(attribute_value, list):

                    attribute_value = attribute_value.split()

                return value in attribute_value

            return _includes_value

        elif operator == '^':

            # string representation of `attribute` starts with `value`

            return lambda el: el._attr_value_as_string(

                attribute, '').startswith(value)

        elif operator == '$':

            # string representation of `attribute` ends with `value`

            return lambda el: el._attr_value_as_string(

                attribute, '').endswith(value)

        elif operator == '*':

            # string representation of `attribute` contains `value`

            return lambda el: value in el._attr_value_as_string(attribute, '')

        elif operator == '|':

            # string representation of `attribute` is either exactly

            # `value` or starts with `value` and then a dash.

            def _is_or_starts_with_dash(element):

                attribute_value = element._attr_value_as_string(attribute, '')

                return (attribute_value == value or attribute_value.startswith(

                        value + '-'))

            return _is_or_starts_with_dash

        else:

            return lambda el: el.has_attr(attribute)

    # Old non-property versions of the generators, for backwards

    # compatibility with BS3.

    def nextGenerator(self):

        return self.next_elements

    def nextSiblingGenerator(self):

        return self.next_siblings

    def previousGenerator(self):

        return self.previous_elements

    def previousSiblingGenerator(self):

        return self.previous_siblings

    def parentGenerator(self):

        return self.parents

class NavigableString(str, PageElement):

    PREFIX = ''

    SUFFIX = ''

    # We can't tell just by looking at a string whether it's contained

    # in an XML document or an HTML document.

    known_xml = None

    def __new__(cls, value):

        """Create a new NavigableString.

        When unpickling a NavigableString, this method is called with

        the string in DEFAULT_OUTPUT_ENCODING. That encoding needs to be

        passed in to the superclass's __new__ or the superclass won't know

        how to handle non-ASCII characters.

        """

        if isinstance(value, str):

            u = str.__new__(cls, value)

        else:

            u = str.__new__(cls, value, DEFAULT_OUTPUT_ENCODING)

        u.setup()

        return u

    def __copy__(self):

        """A copy of a NavigableString has the same contents and class

        as the original, but it is not connected to the parse tree.

        """

        return type(self)(self)

    def __getnewargs__(self):

        return (str(self),)

    def __getattr__(self, attr):

        """text.string gives you text. This is for backwards

        compatibility for Navigable*String, but for CData* it lets you

        get the string without the CData wrapper."""

        if attr == 'string':

            return self

        else:

            raise AttributeError(

                "'%s' object has no attribute '%s'" % (

                    self.__class__.__name__, attr))

    def output_ready(self, formatter="minimal"):

        output = self.format_string(self, formatter)

        return self.PREFIX + output + self.SUFFIX

    @property

    def name(self):

        return None

    @name.setter

    def name(self, name):

        raise AttributeError("A NavigableString cannot be given a name.")

class PreformattedString(NavigableString):

    """A NavigableString not subject to the normal formatting rules.

    The string will be passed into the formatter (to trigger side effects),

    but the return value will be ignored.

    """

    def output_ready(self, formatter="minimal"):

        """CData strings are passed into the formatter.

        But the return value is ignored."""

        self.format_string(self, formatter)

        return self.PREFIX + self + self.SUFFIX

class CData(PreformattedString):

    PREFIX = '<![CDATA['

    SUFFIX = ']]>'

class ProcessingInstruction(PreformattedString):

    """A SGML processing instruction."""

    PREFIX = '<?'

    SUFFIX = '>'

class XMLProcessingInstruction(ProcessingInstruction):

    """An XML processing instruction."""

    PREFIX = '<?'

    SUFFIX = '?>'

class Comment(PreformattedString):

    PREFIX = '<!--'

    SUFFIX = '-->'

class Declaration(PreformattedString):

    PREFIX = '<?'

    SUFFIX = '?>'

class Doctype(PreformattedString):

    @classmethod

    def for_name_and_ids(cls, name, pub_id, system_id):

        value = name or ''

        if pub_id is not None:

            value += ' PUBLIC "%s"' % pub_id

            if system_id is not None:

                value += ' "%s"' % system_id

        elif system_id is not None:

            value += ' SYSTEM "%s"' % system_id

        return Doctype(value)

    PREFIX = '<!DOCTYPE '

    SUFFIX = '>\n'

class Tag(PageElement):

    """Represents a found HTML tag with its attributes and contents."""

    def __init__(self, parser=None, builder=None, name=None, namespace=None,

                 prefix=None, attrs=None, parent=None, previous=None,

                 is_xml=None):

        "Basic constructor."

        if parser is None:

            self.parser_class = None

        else:

            # We don't actually store the parser object: that lets extracted

            # chunks be garbage-collected.

            self.parser_class = parser.__class__

        if name is None:

            raise ValueError("No value provided for new tag's name.")

        self.name = name

        self.namespace = namespace

        self.prefix = prefix

        if builder is not None:

            preserve_whitespace_tags = builder.preserve_whitespace_tags

        else:

            if is_xml:

                preserve_whitespace_tags = []

            else:

                preserve_whitespace_tags = HTMLAwareEntitySubstitution.preserve_whitespace_tags

        self.preserve_whitespace_tags = preserve_whitespace_tags

        if attrs is None:

            attrs = {}

        elif attrs:

            if builder is not None and builder.cdata_list_attributes:

                attrs = builder._replace_cdata_list_attribute_values(

                    self.name, attrs)

            else:

                attrs = dict(attrs)

        else:

            attrs = dict(attrs)

        # If possible, determine ahead of time whether this tag is an

        # XML tag.

        if builder:

            self.known_xml = builder.is_xml

        else:

            self.known_xml = is_xml

        self.attrs = attrs

        self.contents = []

        self.setup(parent, previous)

        self.hidden = False

        # Set up any substitutions, such as the charset in a META tag.

        if builder is not None:

            builder.set_up_substitutions(self)

            self.can_be_empty_element = builder.can_be_empty_element(name)

        else:

            self.can_be_empty_element = False

    parserClass = _alias("parser_class")  # BS3

    def __copy__(self):

        """A copy of a Tag is a new Tag, unconnected to the parse tree.

        Its contents are a copy of the old Tag's contents.

        """

        clone = type(self)(None, self.builder, self.name, self.namespace,

                           self.prefix, self.attrs, is_xml=self._is_xml)

        for attr in ('can_be_empty_element', 'hidden'):

            setattr(clone, attr, getattr(self, attr))

        for child in self.contents:

            clone.append(child.__copy__())

        return clone

    @property

    def is_empty_element(self):

        """Is this tag an empty-element tag? (aka a self-closing tag)

        A tag that has contents is never an empty-element tag.

        A tag that has no contents may or may not be an empty-element

        tag. It depends on the builder used to create the tag. If the

        builder has a designated list of empty-element tags, then only

        a tag whose name shows up in that list is considered an

        empty-element tag.

        If the builder has no designated list of empty-element tags,

        then any tag with no contents is an empty-element tag.

        """

        return len(self.contents) == 0 and self.can_be_empty_element

    isSelfClosing = is_empty_element  # BS3

    @property

    def string(self):

        """Convenience property to get the single string within this tag.

        :Return: If this tag has a single string child, return value

         is that string. If this tag has no children, or more than one

         child, return value is None. If this tag has one child tag,

         return value is the 'string' attribute of the child tag,

         recursively.

        """

        if len(self.contents) != 1:

            return None

        child = self.contents[0]

        if isinstance(child, NavigableString):

            return child

        return child.string

    @string.setter

    def string(self, string):

        self.clear()

        self.append(string.__class__(string))

    def _all_strings(self, strip=False, types=(NavigableString, CData)):

        """Yield all strings of certain classes, possibly stripping them.

        By default, yields only NavigableString and CData objects. So

        no comments, processing instructions, etc.

        """

        for descendant in self.descendants:

            if (

                (types is None and not isinstance(descendant, NavigableString))

                or

                (types is not None and type(descendant) not in types)):

                continue

            if strip:

                descendant = descendant.strip()

                if len(descendant) == 0:

                    continue

            yield descendant

    strings = property(_all_strings)

    @property

    def stripped_strings(self):

        for string in self._all_strings(True):

            yield string

    def get_text(self, separator="", strip=False,

                 types=(NavigableString, CData)):

        """

        Get all child strings, concatenated using the given separator.

        """

        return separator.join([s for s in self._all_strings(

                    strip, types=types)])

    getText = get_text

    text = property(get_text)

    def decompose(self):

        """Recursively destroys the contents of this tree."""

        self.extract()

        i = self

        while i is not None:

            next = i.next_element

            i.__dict__.clear()

            i.contents = []

            i = next

    def clear(self, decompose=False):

        """

        Extract all children. If decompose is True, decompose instead.

        """

        if decompose:

            for element in self.contents[:]:

                if isinstance(element, Tag):

                    element.decompose()

                else:

                    element.extract()

        else:

            for element in self.contents[:]:

                element.extract()

    def index(self, element):

        """

        Find the index of a child by identity, not value. Avoids issues with

        tag.contents.index(element) getting the index of equal elements.

        """

        for i, child in enumerate(self.contents):

            if child is element:

                return i

        raise ValueError("Tag.index: element not in tag")

    def get(self, key, default=None):

        """Returns the value of the 'key' attribute for the tag, or

        the value given for 'default' if it doesn't have that

        attribute."""

        return self.attrs.get(key, default)

    def get_attribute_list(self, key, default=None):

        """The same as get(), but always returns a list."""

        value = self.get(key, default)

        if not isinstance(value, list):

            value = [value]

        return value

    def has_attr(self, key):

        return key in self.attrs

    def __hash__(self):

        return str(self).__hash__()

    def __getitem__(self, key):

        """tag[key] returns the value of the 'key' attribute for the tag,

        and throws an exception if it's not there."""

        return self.attrs[key]

    def __iter__(self):

        "Iterating over a tag iterates over its contents."

        return iter(self.contents)

    def __len__(self):

        "The length of a tag is the length of its list of contents."

        return len(self.contents)

    def __contains__(self, x):

        return x in self.contents

    def __bool__(self):

        "A tag is non-None even if it has no contents."

        return True

    def __setitem__(self, key, value):

        """Setting tag[key] sets the value of the 'key' attribute for the

        tag."""

        self.attrs[key] = value

    def __delitem__(self, key):

        "Deleting tag[key] deletes all 'key' attributes for the tag."

        self.attrs.pop(key, None)

    def __call__(self, *args, **kwargs):

        """Calling a tag like a function is the same as calling its

        find_all() method. Eg. tag('a') returns a list of all the A tags

        found within this tag."""

        return self.find_all(*args, **kwargs)

    def __getattr__(self, tag):

        #print "Getattr %s.%s" % (self.__class__, tag)

        if len(tag) > 3 and tag.endswith('Tag'):

            # BS3: soup.aTag -> "soup.find("a")

            tag_name = tag[:-3]

            warnings.warn(

                '.%(name)sTag is deprecated, use .find("%(name)s") instead. If you really were looking for a tag called %(name)sTag, use .find("%(name)sTag")' % dict(

                    name=tag_name

                )

            )

            return self.find(tag_name)

        # We special case contents to avoid recursion.

        elif not tag.startswith("__") and not tag == "contents":

            return self.find(tag)

        raise AttributeError(

            "'%s' object has no attribute '%s'" % (self.__class__, tag))

    def __eq__(self, other):

        """Returns true iff this tag has the same name, the same attributes,

        and the same contents (recursively) as the given tag."""

        if self is other:

            return True

        if (not hasattr(other, 'name') or

            not hasattr(other, 'attrs') or

            not hasattr(other, 'contents') or

            self.name != other.name or

            self.attrs != other.attrs or

            len(self) != len(other)):

            return False

        for i, my_child in enumerate(self.contents):

            if my_child != other.contents[i]:

                return False

        return True

    def __ne__(self, other):

        """Returns true iff this tag is not identical to the other tag,

        as defined in __eq__."""

        return not self == other

    def __repr__(self, encoding="unicode-escape"):

        """Renders this tag as a string."""

        if PY3K:

            # "The return value must be a string object", i.e. Unicode

            return self.decode()

        else:

            # "The return value must be a string object", i.e. a bytestring.

            # By convention, the return value of __repr__ should also be

            # an ASCII string.

            return self.encode(encoding)

    def __unicode__(self):

        return self.decode()

    def __str__(self):

        if PY3K:

            return self.decode()

        else:

            return self.encode()

    if PY3K:

        __str__ = __repr__ = __unicode__

    def encode(self, encoding=DEFAULT_OUTPUT_ENCODING,

               indent_level=None, formatter="minimal",

               errors="xmlcharrefreplace"):

        # Turn the data structure into Unicode, then encode the

        # Unicode.

        u = self.decode(indent_level, encoding, formatter)

        return u.encode(encoding, errors)

    def _should_pretty_print(self, indent_level):

        """Should this tag be pretty-printed?"""

        return (

            indent_level is not None

            and self.name not in self.preserve_whitespace_tags

        )

    def decode(self, indent_level=None,

               eventual_encoding=DEFAULT_OUTPUT_ENCODING,

               formatter="minimal"):

        """Returns a Unicode representation of this tag and its contents.

        :param eventual_encoding: The tag is destined to be

           encoded into this encoding. This method is _not_

           responsible for performing that encoding. This information

           is passed in so that it can be substituted in if the

           document contains a <META> tag that mentions the document's

           encoding.

        """

        # First off, turn a string formatter into a Formatter object. This

        # will stop the lookup from happening over and over again.

        if not isinstance(formatter, Formatter) and not callable(formatter):

            formatter = self._formatter_for_name(formatter)

        attrs = []

        if self.attrs:

            for key, val in sorted(self.attrs.items()):

                if val is None:

                    decoded = key

                else:

                    if isinstance(val, list) or isinstance(val, tuple):

                        val = ' '.join(val)

                    elif not isinstance(val, str):

                        val = str(val)

                    elif (

                        isinstance(val, AttributeValueWithCharsetSubstitution)

                        and eventual_encoding is not None):

                        val = val.encode(eventual_encoding)

                    text = self.format_string(val, formatter)

                    decoded = (

                        str(key) + '='

                        + EntitySubstitution.quoted_attribute_value(text))

                attrs.append(decoded)

        close = ''

        closeTag = ''

        prefix = ''

        if self.prefix:

            prefix = self.prefix + ":"

        if self.is_empty_element:

            close = ''

            if isinstance(formatter, Formatter):

                close = formatter.void_element_close_prefix or close

        else:

            closeTag = '</%s%s>' % (prefix, self.name)

        pretty_print = self._should_pretty_print(indent_level)

        space = ''

        indent_space = ''

        if indent_level is not None:

            indent_space = (' ' * (indent_level - 1))

        if pretty_print:

            space = indent_space

            indent_contents = indent_level + 1

        else:

            indent_contents = None

        contents = self.decode_contents(

            indent_contents, eventual_encoding, formatter)

        if self.hidden:

            # This is the 'document root' object.

            s = contents

        else:

            s = []

            attribute_string = ''

            if attrs:

                attribute_string = ' ' + ' '.join(attrs)

            if indent_level is not None:

                # Even if this particular tag is not pretty-printed,

                # we should indent up to the start of the tag.

                s.append(indent_space)

            s.append('<%s%s%s%s>' % (

                    prefix, self.name, attribute_string, close))

            if pretty_print:

                s.append("\n")

            s.append(contents)

            if pretty_print and contents and contents[-1] != "\n":

                s.append("\n")

            if pretty_print and closeTag:

                s.append(space)

            s.append(closeTag)

            if indent_level is not None and closeTag and self.next_sibling:

                # Even if this particular tag is not pretty-printed,

                # we're now done with the tag, and we should add a

                # newline if appropriate.

                s.append("\n")

            s = ''.join(s)

        return s

    def prettify(self, encoding=None, formatter="minimal"):

        if encoding is None:

            return self.decode(True, formatter=formatter)

        else:

            return self.encode(encoding, True, formatter=formatter)

    def decode_contents(self, indent_level=None,

                       eventual_encoding=DEFAULT_OUTPUT_ENCODING,

                       formatter="minimal"):

        """Renders the contents of this tag as a Unicode string.

        :param indent_level: Each line of the rendering will be

           indented this many spaces.

        :param eventual_encoding: The tag is destined to be

           encoded into this encoding. This method is _not_

           responsible for performing that encoding. This information

           is passed in so that it can be substituted in if the

           document contains a <META> tag that mentions the document's

           encoding.

        :param formatter: The output formatter responsible for converting

           entities to Unicode characters.

        """

        # First off, turn a string formatter into a Formatter object. This

        # will stop the lookup from happening over and over again.

        if not isinstance(formatter, Formatter) and not callable(formatter):

            formatter = self._formatter_for_name(formatter)

        pretty_print = (indent_level is not None)

        s = []

        for c in self:

            text = None

            if isinstance(c, NavigableString):

                text = c.output_ready(formatter)

            elif isinstance(c, Tag):

                s.append(c.decode(indent_level, eventual_encoding,

                                  formatter))

            if text and indent_level and not self.name == 'pre':

                text = text.strip()

            if text:

                if pretty_print and not self.name == 'pre':

                    s.append(" " * (indent_level - 1))

                s.append(text)

                if pretty_print and not self.name == 'pre':

                    s.append("\n")

        return ''.join(s)

    def encode_contents(

        self, indent_level=None, encoding=DEFAULT_OUTPUT_ENCODING,

        formatter="minimal"):

        """Renders the contents of this tag as a bytestring.

        :param indent_level: Each line of the rendering will be

           indented this many spaces.

        :param eventual_encoding: The bytestring will be in this encoding.

        :param formatter: The output formatter responsible for converting

           entities to Unicode characters.

        """

        contents = self.decode_contents(indent_level, encoding, formatter)

        return contents.encode(encoding)

    # Old method for BS3 compatibility

    def renderContents(self, encoding=DEFAULT_OUTPUT_ENCODING,

                       prettyPrint=False, indentLevel=0):

        if not prettyPrint:

            indentLevel = None

        return self.encode_contents(

            indent_level=indentLevel, encoding=encoding)

    #Soup methods

    def find(self, name=None, attrs={}, recursive=True, text=None,

             **kwargs):

        """Return only the first child of this Tag matching the given

        criteria."""

        r = None

        l = self.find_all(name, attrs, recursive, text, 1, **kwargs)

        if l:

            r = l[0]

        return r

    findChild = find

    def find_all(self, name=None, attrs={}, recursive=True, text=None,

                 limit=None, **kwargs):

        """Extracts a list of Tag objects that match the given

        criteria.  You can specify the name of the Tag and any

        attributes you want the Tag to have.

        The value of a key-value pair in the 'attrs' map can be a

        string, a list of strings, a regular expression object, or a

        callable that takes a string and returns whether or not the

        string matches for some custom definition of 'matches'. The

        same is true of the tag name."""

        generator = self.descendants

        if not recursive:

            generator = self.children

        return self._find_all(name, attrs, text, limit, generator, **kwargs)

    findAll = find_all       # BS3

    findChildren = find_all  # BS2

    #Generator methods

    @property

    def children(self):

        # return iter() to make the purpose of the method clear

        return iter(self.contents)  # XXX This seems to be untested.

    @property

    def descendants(self):

        if not len(self.contents):

            return

        stopNode = self._last_descendant().next_element

        current = self.contents[0]

        while current is not stopNode:

            yield current

            current = current.next_element

    # CSS selector code

    _selector_combinators = ['>', '+', '~']

    _select_debug = False

    quoted_colon = re.compile('"[^"]*:[^"]*"')

    def select_one(self, selector):

        """Perform a CSS selection operation on the current element."""

        value = self.select(selector, limit=1)

        if value:

            return value[0]

        return None

    def select(self, selector, _candidate_generator=None, limit=None):

        """Perform a CSS selection operation on the current element."""

        # Handle grouping selectors if ',' exists, ie: p,a

        if ',' in selector:

            context = []

            selectors = [x.strip() for x in selector.split(",")]

            # If a selector is mentioned multiple times we don't want

            # to use it more than once.

            used_selectors = set()

            # We also don't want to select the same element more than once,

            # if it's matched by multiple selectors.

            selected_object_ids = set()

            for partial_selector in selectors:

                if partial_selector == '':

                    raise ValueError('Invalid group selection syntax: %s' % selector)

                if partial_selector in used_selectors:

                    continue

                used_selectors.add(partial_selector)

                candidates = self.select(partial_selector, limit=limit)

                for candidate in candidates:

                    # This lets us distinguish between distinct tags that

                    # represent the same markup.

                    object_id = id(candidate)

                    if object_id not in selected_object_ids:

                        context.append(candidate)

                        selected_object_ids.add(object_id)

                if limit and len(context) >= limit:

                    break

            return context

        tokens = shlex.split(selector)

        current_context = [self]

        if tokens[-1] in self._selector_combinators:

            raise ValueError(

                'Final combinator "%s" is missing an argument.' % tokens[-1])

        if self._select_debug:

            print('Running CSS selector "%s"' % selector)

        for index, token in enumerate(tokens):

            new_context = []

            new_context_ids = set([])

            if tokens[index-1] in self._selector_combinators:

                # This token was consumed by the previous combinator. Skip it.

                if self._select_debug:

                    print('  Token was consumed by the previous combinator.')

                continue

            if self._select_debug:

                print(' Considering token "%s"' % token)

            recursive_candidate_generator = None

            tag_name = None

            # Each operation corresponds to a checker function, a rule

            # for determining whether a candidate matches the

            # selector. Candidates are generated by the active

            # iterator.

            checker = None

            m = self.attribselect_re.match(token)

            if m is not None:

                # Attribute selector

                tag_name, attribute, operator, value = m.groups()

                checker = self._attribute_checker(operator, attribute, value)

            elif '#' in token:

                # ID selector

                tag_name, tag_id = token.split('#', 1)

                def id_matches(tag):

                    return tag.get('id', None) == tag_id

                checker = id_matches

            elif '.' in token:

                # Class selector

                tag_name, klass = token.split('.', 1)

                classes = set(klass.split('.'))

                def classes_match(candidate):

                    return classes.issubset(candidate.get('class', []))

                checker = classes_match

            elif ':' in token and not self.quoted_colon.search(token):

                # Pseudo-class

                tag_name, pseudo = token.split(':', 1)

                if tag_name == '':

                    raise ValueError(

                        "A pseudo-class must be prefixed with a tag name.")

                pseudo_attributes = re.match(r'([a-zA-Z\d-]+)\(([a-zA-Z\d]+)\)', pseudo)

                found = []

                if pseudo_attributes is None:

                    pseudo_type = pseudo

                    pseudo_value = None

                else:

                    pseudo_type, pseudo_value = pseudo_attributes.groups()

                if pseudo_type == 'nth-of-type':

                    try:

                        pseudo_value = int(pseudo_value)

                    except:

                        raise NotImplementedError(

                            'Only numeric values are currently supported for the nth-of-type pseudo-class.')

                    if pseudo_value < 1:

                        raise ValueError(

                            'nth-of-type pseudo-class value must be at least 1.')

                    class Counter(object):

                        def __init__(self, destination):

                            self.count = 0

                            self.destination = destination

                        def nth_child_of_type(self, tag):

                            self.count += 1

                            if self.count == self.destination:

                                return True

                            else:

                                return False

                    checker = Counter(pseudo_value).nth_child_of_type

                else:

                    raise NotImplementedError(

                        'Only the following pseudo-classes are implemented: nth-of-type.')

            elif token == '*':

                # Star selector -- matches everything

                pass

            elif token == '>':

                # Run the next token as a CSS selector against the

                # direct children of each tag in the current context.

                recursive_candidate_generator = lambda tag: tag.children

            elif token == '~':

                # Run the next token as a CSS selector against the

                # siblings of each tag in the current context.

                recursive_candidate_generator = lambda tag: tag.next_siblings

            elif token == '+':

                # For each tag in the current context, run the next

                # token as a CSS selector against the tag's next

                # sibling that's a tag.

                def next_tag_sibling(tag):

                    yield tag.find_next_sibling(True)

                recursive_candidate_generator = next_tag_sibling

            elif self.tag_name_re.match(token):

                # Just a tag name.

                tag_name = token

            else:

                raise ValueError(

                    'Unsupported or invalid CSS selector: "%s"' % token)

            if recursive_candidate_generator:

                # This happens when the selector looks like  "> foo".

                #

                # The generator calls select() recursively on every

                # member of the current context, passing in a different

                # candidate generator and a different selector.

                #

                # In the case of "> foo", the candidate generator is

                # one that yields a tag's direct children (">"), and

                # the selector is "foo".

                next_token = tokens[index+1]

                def recursive_select(tag):

                    if self._select_debug:

                        print('    Calling select("%s") recursively on %s %s' % (next_token, tag.name, tag.attrs))

                        print('-' * 40)

                    for i in tag.select(next_token, recursive_candidate_generator):

                        if self._select_debug:

                            print('(Recursive select picked up candidate %s %s)' % (i.name, i.attrs))

                        yield i

                    if self._select_debug:

                        print('-' * 40)

                _use_candidate_generator = recursive_select

            elif _candidate_generator is None:

                # By default, a tag's candidates are all of its

                # children. If tag_name is defined, only yield tags

                # with that name.

                if self._select_debug:

                    if tag_name:

                        check = "[any]"

                    else:

                        check = tag_name

                    print('   Default candidate generator, tag name="%s"' % check)

                if self._select_debug:

                    # This is redundant with later code, but it stops

                    # a bunch of bogus tags from cluttering up the

                    # debug log.

                    def default_candidate_generator(tag):

                        for child in tag.descendants:

                            if not isinstance(child, Tag):

                                continue

                            if tag_name and not child.name == tag_name:

                                continue

                            yield child

                    _use_candidate_generator = default_candidate_generator

                else:

                    _use_candidate_generator = lambda tag: tag.descendants

            else:

                _use_candidate_generator = _candidate_generator

            count = 0

            for tag in current_context:

                if self._select_debug:

                    print("    Running candidate generator on %s %s" % (

                        tag.name, repr(tag.attrs)))

                for candidate in _use_candidate_generator(tag):

                    if not isinstance(candidate, Tag):

                        continue

                    if tag_name and candidate.name != tag_name:

                        continue

                    if checker is not None:

                        try:

                            result = checker(candidate)

                        except StopIteration:

                            # The checker has decided we should no longer

                            # run the generator.

                            break

                    if checker is None or result:

                        if self._select_debug:

                            print("     SUCCESS %s %s" % (candidate.name, repr(candidate.attrs)))

                        if id(candidate) not in new_context_ids:

                            # If a tag matches a selector more than once,

                            # don't include it in the context more than once.

                            new_context.append(candidate)

                            new_context_ids.add(id(candidate))

                    elif self._select_debug:

                        print("     FAILURE %s %s" % (candidate.name, repr(candidate.attrs)))

            current_context = new_context

        if limit and len(current_context) >= limit:

            current_context = current_context[:limit]

        if self._select_debug:

            print("Final verdict:")

            for i in current_context:

                print(" %s %s" % (i.name, i.attrs))

        return current_context

    # Old names for backwards compatibility

    def childGenerator(self):

        return self.children

    def recursiveChildGenerator(self):

        return self.descendants

    def has_key(self, key):

        """This was kind of misleading because has_key() (attributes)

        was different from __in__ (contents). has_key() is gone in

        Python 3, anyway."""

        warnings.warn('has_key is deprecated. Use has_attr("%s") instead.' % (

                key))

        return self.has_attr(key)

# Next, a couple classes to represent queries and their results.

class SoupStrainer(object):

    """Encapsulates a number of ways of matching a markup element (tag or

    text)."""

    def __init__(self, name=None, attrs={}, text=None, **kwargs):

        self.name = self._normalize_search_value(name)

        if not isinstance(attrs, dict):

            # Treat a non-dict value for attrs as a search for the 'class'

            # attribute.

            kwargs['class'] = attrs

            attrs = None

        if 'class_' in kwargs:

            # Treat class_="foo" as a search for the 'class'

            # attribute, overriding any non-dict value for attrs.

            kwargs['class'] = kwargs['class_']

            del kwargs['class_']

        if kwargs:

            if attrs:

                attrs = attrs.copy()

                attrs.update(kwargs)

            else:

                attrs = kwargs

        normalized_attrs = {}

        for key, value in list(attrs.items()):

            normalized_attrs[key] = self._normalize_search_value(value)

        self.attrs = normalized_attrs

        self.text = self._normalize_search_value(text)

    def _normalize_search_value(self, value):

        # Leave it alone if it's a Unicode string, a callable, a

        # regular expression, a boolean, or None.

        if (isinstance(value, str) or callable(value) or hasattr(value, 'match')

            or isinstance(value, bool) or value is None):

            return value

        # If it's a bytestring, convert it to Unicode, treating it as UTF-8.

        if isinstance(value, bytes):

            return value.decode("utf8")

        # If it's listlike, convert it into a list of strings.

        if hasattr(value, '__iter__'):

            new_value = []

            for v in value:

                if (hasattr(v, '__iter__') and not isinstance(v, bytes)

                    and not isinstance(v, str)):

                    # This is almost certainly the user's mistake. In the

                    # interests of avoiding infinite loops, we'll let

                    # it through as-is rather than doing a recursive call.

                    new_value.append(v)

                else:

                    new_value.append(self._normalize_search_value(v))

            return new_value

        # Otherwise, convert it into a Unicode string.

        # The unicode(str()) thing is so this will do the same thing on Python 2

        # and Python 3.

        return str(str(value))

    def __str__(self):

        if self.text:

            return self.text

        else:

            return "%s|%s" % (self.name, self.attrs)

    def search_tag(self, markup_name=None, markup_attrs={}):

        found = None

        markup = None

        if isinstance(markup_name, Tag):

            markup = markup_name

            markup_attrs = markup

        call_function_with_tag_data = (

            isinstance(self.name, Callable)

            and not isinstance(markup_name, Tag))

        if ((not self.name)

            or call_function_with_tag_data

            or (markup and self._matches(markup, self.name))

            or (not markup and self._matches(markup_name, self.name))):

            if call_function_with_tag_data:

                match = self.name(markup_name, markup_attrs)

            else:

                match = True

                markup_attr_map = None

                for attr, match_against in list(self.attrs.items()):

                    if not markup_attr_map:

                        if hasattr(markup_attrs, 'get'):

                            markup_attr_map = markup_attrs

                        else:

                            markup_attr_map = {}

                            for k, v in markup_attrs:

                                markup_attr_map[k] = v

                    attr_value = markup_attr_map.get(attr)

                    if not self._matches(attr_value, match_against):

                        match = False

                        break

            if match:

                if markup:

                    found = markup

                else:

                    found = markup_name

        if found and self.text and not self._matches(found.string, self.text):

            found = None

        return found

    searchTag = search_tag

    def search(self, markup):

        # print 'looking for %s in %s' % (self, markup)

        found = None

        # If given a list of items, scan it for a text element that

        # matches.

        if hasattr(markup, '__iter__') and not isinstance(markup, (Tag, str)):

            for element in markup:

                if isinstance(element, NavigableString) \

                       and self.search(element):

                    found = element

                    break

        # If it's a Tag, make sure its name or attributes match.

        # Don't bother with Tags if we're searching for text.

        elif isinstance(markup, Tag):

            if not self.text or self.name or self.attrs:

                found = self.search_tag(markup)

        # If it's text, make sure the text matches.

        elif isinstance(markup, NavigableString) or \

                 isinstance(markup, str):

            if not self.name and not self.attrs and self._matches(markup, self.text):

                found = markup

        else:

            raise Exception(

                "I don't know how to match against a %s" % markup.__class__)

        return found

    def _matches(self, markup, match_against, already_tried=None):

        # print u"Matching %s against %s" % (markup, match_against)

        result = False

        if isinstance(markup, list) or isinstance(markup, tuple):

            # This should only happen when searching a multi-valued attribute

            # like 'class'.

            for item in markup:

                if self._matches(item, match_against):

                    return True

            # We didn't match any particular value of the multivalue

            # attribute, but maybe we match the attribute value when

            # considered as a string.

            if self._matches(' '.join(markup), match_against):

                return True

            return False

        if match_against is True:

            # True matches any non-None value.

            return markup is not None

        if isinstance(match_against, Callable):

            return match_against(markup)

        # Custom callables take the tag as an argument, but all

        # other ways of matching match the tag name as a string.

        original_markup = markup

        if isinstance(markup, Tag):

            markup = markup.name

        # Ensure that `markup` is either a Unicode string, or None.

        markup = self._normalize_search_value(markup)

        if markup is None:

            # None matches None, False, an empty string, an empty list, and so on.

            return not match_against

        if (hasattr(match_against, '__iter__')

            and not isinstance(match_against, str)):

            # We're asked to match against an iterable of items.

            # The markup must be match at least one item in the

            # iterable. We'll try each one in turn.

            #

            # To avoid infinite recursion we need to keep track of

            # items we've already seen.

            if not already_tried:

                already_tried = set()

            for item in match_against:

                if item.__hash__:

                    key = item

                else:

                    key = id(item)

                if key in already_tried:

                    continue

                else:

                    already_tried.add(key)

                    if self._matches(original_markup, item, already_tried):

                        return True

            else:

                return False

        # Beyond this point we might need to run the test twice: once against

        # the tag's name and once against its prefixed name.

        match = False

        if not match and isinstance(match_against, str):

            # Exact string match

            match = markup == match_against

        if not match and hasattr(match_against, 'search'):

            # Regexp match

            return match_against.search(markup)

        if (not match

            and isinstance(original_markup, Tag)

            and original_markup.prefix):

            # Try the whole thing again with the prefixed tag name.

            return self._matches(

                original_markup.prefix + ':' + original_markup.name, match_against

            )

        return match

class ResultSet(list):

    """A ResultSet is just a list that keeps track of the SoupStrainer

    that created it."""

    def __init__(self, source, result=()):

        super(ResultSet, self).__init__(result)

        self.source = source

    def __getattr__(self, key):

        raise AttributeError(

            "ResultSet object has no attribute '%s'. You're probably treating a list of items like a single item. Did you call find_all() when you meant to call find()?" % key

        )