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stbi/Lib/site-packages/pip/_vendor/html5lib/treebuilders/__init__.py

+"""A collection of modules for building different kinds of trees from HTML
+documents.
+
+To create a treebuilder for a new type of tree, you need to do
+implement several things:
+
+1. A set of classes for various types of elements: Document, Doctype, Comment,
+   Element. These must implement the interface of ``base.treebuilders.Node``
+   (although comment nodes have a different signature for their constructor,
+   see ``treebuilders.etree.Comment``) Textual content may also be implemented
+   as another node type, or not, as your tree implementation requires.
+
+2. A treebuilder object (called ``TreeBuilder`` by convention) that inherits
+   from ``treebuilders.base.TreeBuilder``. This has 4 required attributes:
+
+   * ``documentClass`` - the class to use for the bottommost node of a document
+   * ``elementClass`` - the class to use for HTML Elements
+   * ``commentClass`` - the class to use for comments
+   * ``doctypeClass`` - the class to use for doctypes
+
+   It also has one required method:
+
+   * ``getDocument`` - Returns the root node of the complete document tree
+
+3. If you wish to run the unit tests, you must also create a ``testSerializer``
+   method on your treebuilder which accepts a node and returns a string
+   containing Node and its children serialized according to the format used in
+   the unittests
+
+"""
+
+from __future__ import absolute_import, division, unicode_literals
+
+from .._utils import default_etree
+
+treeBuilderCache = {}
+
+
+def getTreeBuilder(treeType, implementation=None, **kwargs):
+    """Get a TreeBuilder class for various types of trees with built-in support
+
+    :arg treeType: the name of the tree type required (case-insensitive). Supported
+        values are:
+
+        * "dom" - A generic builder for DOM implementations, defaulting to a
+          xml.dom.minidom based implementation.
+        * "etree" - A generic builder for tree implementations exposing an
+          ElementTree-like interface, defaulting to xml.etree.cElementTree if
+          available and xml.etree.ElementTree if not.
+        * "lxml" - A etree-based builder for lxml.etree, handling limitations
+          of lxml's implementation.
+
+    :arg implementation: (Currently applies to the "etree" and "dom" tree
+        types). A module implementing the tree type e.g. xml.etree.ElementTree
+        or xml.etree.cElementTree.
+
+    :arg kwargs: Any additional options to pass to the TreeBuilder when
+        creating it.
+
+    Example:
+
+    >>> from html5lib.treebuilders import getTreeBuilder
+    >>> builder = getTreeBuilder('etree')
+
+    """
+
+    treeType = treeType.lower()
+    if treeType not in treeBuilderCache:
+        if treeType == "dom":
+            from . import dom
+            # Come up with a sane default (pref. from the stdlib)
+            if implementation is None:
+                from xml.dom import minidom
+                implementation = minidom
+            # NEVER cache here, caching is done in the dom submodule
+            return dom.getDomModule(implementation, **kwargs).TreeBuilder
+        elif treeType == "lxml":
+            from . import etree_lxml
+            treeBuilderCache[treeType] = etree_lxml.TreeBuilder
+        elif treeType == "etree":
+            from . import etree
+            if implementation is None:
+                implementation = default_etree
+            # NEVER cache here, caching is done in the etree submodule
+            return etree.getETreeModule(implementation, **kwargs).TreeBuilder
+        else:
+            raise ValueError("""Unrecognised treebuilder "%s" """ % treeType)
+    return treeBuilderCache.get(treeType)