two version of R2R are hereHEADmaster

1 files changed, 1781 insertions, 0 deletions

diff --git a/.venv/lib/python3.12/site-packages/lxml/serializer.pxi b/.venv/lib/python3.12/site-packages/lxml/serializer.pxi
new file mode 100644
index 00000000..f0de0f9f
--- /dev/null
+++ b/.venv/lib/python3.12/site-packages/lxml/serializer.pxi
@@ -0,0 +1,1781 @@
+# XML serialization and output functions
+
+cdef object GzipFile
+from gzip import GzipFile
+
+
+cdef class SerialisationError(LxmlError):
+    """A libxml2 error that occurred during serialisation.
+    """
+
+
+cdef enum _OutputMethods:
+    OUTPUT_METHOD_XML
+    OUTPUT_METHOD_HTML
+    OUTPUT_METHOD_TEXT
+
+
+cdef int _findOutputMethod(method) except -1:
+    if method is None:
+        return OUTPUT_METHOD_XML
+    method = method.lower()
+    if method == "xml":
+        return OUTPUT_METHOD_XML
+    if method == "html":
+        return OUTPUT_METHOD_HTML
+    if method == "text":
+        return OUTPUT_METHOD_TEXT
+    raise ValueError(f"unknown output method {method!r}")
+
+
+cdef _textToString(xmlNode* c_node, encoding, bint with_tail):
+    cdef bint needs_conversion
+    cdef const_xmlChar* c_text
+    cdef xmlNode* c_text_node
+    cdef tree.xmlBuffer* c_buffer
+    cdef int error_result
+
+    c_buffer = tree.xmlBufferCreate()
+    if c_buffer is NULL:
+        raise MemoryError()
+
+    with nogil:
+        error_result = tree.xmlNodeBufGetContent(c_buffer, c_node)
+        if with_tail:
+            c_text_node = _textNodeOrSkip(c_node.next)
+            while c_text_node is not NULL:
+                tree.xmlBufferWriteChar(c_buffer, <const_char*>c_text_node.content)
+                c_text_node = _textNodeOrSkip(c_text_node.next)
+        c_text = tree.xmlBufferContent(c_buffer)
+
+    if error_result < 0 or c_text is NULL:
+        tree.xmlBufferFree(c_buffer)
+        raise SerialisationError, "Error during serialisation (out of memory?)"
+
+    try:
+        needs_conversion = 0
+        if encoding is unicode:
+            needs_conversion = 1
+        elif encoding is not None:
+            # Python prefers lower case encoding names
+            encoding = encoding.lower()
+            if encoding not in ('utf8', 'utf-8'):
+                if encoding == 'ascii':
+                    if isutf8l(c_text, tree.xmlBufferLength(c_buffer)):
+                        # will raise a decode error below
+                        needs_conversion = 1
+                else:
+                    needs_conversion = 1
+
+        if needs_conversion:
+            text = (<const_char*>c_text)[:tree.xmlBufferLength(c_buffer)].decode('utf8')
+            if encoding is not unicode:
+                encoding = _utf8(encoding)
+                text = python.PyUnicode_AsEncodedString(
+                    text, encoding, 'strict')
+        else:
+            text = (<unsigned char*>c_text)[:tree.xmlBufferLength(c_buffer)]
+    finally:
+        tree.xmlBufferFree(c_buffer)
+    return text
+
+
+cdef _tostring(_Element element, encoding, doctype, method,
+               bint write_xml_declaration, bint write_complete_document,
+               bint pretty_print, bint with_tail, int standalone):
+    """Serialize an element to an encoded string representation of its XML
+    tree.
+    """
+    cdef tree.xmlOutputBuffer* c_buffer
+    cdef tree.xmlBuf* c_result_buffer
+    cdef tree.xmlCharEncodingHandler* enchandler
+    cdef const_char* c_enc
+    cdef const_xmlChar* c_version
+    cdef const_xmlChar* c_doctype
+    cdef int c_method
+    cdef int error_result
+    if element is None:
+        return None
+    _assertValidNode(element)
+    c_method = _findOutputMethod(method)
+    if c_method == OUTPUT_METHOD_TEXT:
+        return _textToString(element._c_node, encoding, with_tail)
+    if encoding is None or encoding is unicode:
+        c_enc = NULL
+    else:
+        encoding = _utf8(encoding)
+        c_enc = _cstr(encoding)
+    if doctype is None:
+        c_doctype = NULL
+    else:
+        doctype = _utf8(doctype)
+        c_doctype = _xcstr(doctype)
+    # it is necessary to *and* find the encoding handler *and* use
+    # encoding during output
+    enchandler = tree.xmlFindCharEncodingHandler(c_enc)
+    if enchandler is NULL and c_enc is not NULL:
+        if encoding is not None:
+            encoding = encoding.decode('UTF-8')
+        raise LookupError, f"unknown encoding: '{encoding}'"
+    c_buffer = tree.xmlAllocOutputBuffer(enchandler)
+    if c_buffer is NULL:
+        tree.xmlCharEncCloseFunc(enchandler)
+        raise MemoryError()
+
+    with nogil:
+        _writeNodeToBuffer(c_buffer, element._c_node, c_enc, c_doctype, c_method,
+                           write_xml_declaration, write_complete_document,
+                           pretty_print, with_tail, standalone)
+        tree.xmlOutputBufferFlush(c_buffer)
+        if c_buffer.conv is not NULL:
+            c_result_buffer = c_buffer.conv
+        else:
+            c_result_buffer = c_buffer.buffer
+
+    error_result = c_buffer.error
+    if error_result != xmlerror.XML_ERR_OK:
+        tree.xmlOutputBufferClose(c_buffer)
+        _raiseSerialisationError(error_result)
+
+    try:
+        if encoding is unicode:
+            result = (<unsigned char*>tree.xmlBufContent(
+                c_result_buffer))[:tree.xmlBufUse(c_result_buffer)].decode('UTF-8')
+        else:
+            result = <bytes>(<unsigned char*>tree.xmlBufContent(
+                c_result_buffer))[:tree.xmlBufUse(c_result_buffer)]
+    finally:
+        error_result = tree.xmlOutputBufferClose(c_buffer)
+    if error_result == -1:
+        _raiseSerialisationError(error_result)
+    return result
+
+cdef bytes _tostringC14N(element_or_tree, bint exclusive, bint with_comments, inclusive_ns_prefixes):
+    cdef xmlDoc* c_doc
+    cdef xmlChar* c_buffer = NULL
+    cdef int byte_count = -1
+    cdef bytes result
+    cdef _Document doc
+    cdef _Element element
+    cdef xmlChar **c_inclusive_ns_prefixes
+
+    if isinstance(element_or_tree, _Element):
+        _assertValidNode(<_Element>element_or_tree)
+        doc = (<_Element>element_or_tree)._doc
+        c_doc = _plainFakeRootDoc(doc._c_doc, (<_Element>element_or_tree)._c_node, 0)
+    else:
+        doc = _documentOrRaise(element_or_tree)
+        _assertValidDoc(doc)
+        c_doc = doc._c_doc
+
+    c_inclusive_ns_prefixes = _convert_ns_prefixes(c_doc.dict, inclusive_ns_prefixes) if inclusive_ns_prefixes else NULL
+    try:
+         with nogil:
+             byte_count = c14n.xmlC14NDocDumpMemory(
+                 c_doc, NULL, exclusive, c_inclusive_ns_prefixes, with_comments, &c_buffer)
+
+    finally:
+         _destroyFakeDoc(doc._c_doc, c_doc)
+         if c_inclusive_ns_prefixes is not NULL:
+            python.lxml_free(c_inclusive_ns_prefixes)
+
+    if byte_count < 0 or c_buffer is NULL:
+        if c_buffer is not NULL:
+            tree.xmlFree(c_buffer)
+        raise C14NError, "C14N failed"
+    try:
+        result = c_buffer[:byte_count]
+    finally:
+        tree.xmlFree(c_buffer)
+    return result
+
+cdef _raiseSerialisationError(int error_result):
+    if error_result == xmlerror.XML_ERR_NO_MEMORY:
+        raise MemoryError()
+    message = ErrorTypes._getName(error_result)
+    if message is None:
+        message = f"unknown error {error_result}"
+    raise SerialisationError, message
+
+############################################################
+# low-level serialisation functions
+
+cdef void _writeDoctype(tree.xmlOutputBuffer* c_buffer,
+                        const_xmlChar* c_doctype) noexcept nogil:
+    tree.xmlOutputBufferWrite(c_buffer, tree.xmlStrlen(c_doctype),
+                              <const_char*>c_doctype)
+    tree.xmlOutputBufferWriteString(c_buffer, "\n")
+
+cdef void _writeNodeToBuffer(tree.xmlOutputBuffer* c_buffer,
+                             xmlNode* c_node, const_char* encoding, const_xmlChar* c_doctype,
+                             int c_method, bint write_xml_declaration,
+                             bint write_complete_document,
+                             bint pretty_print, bint with_tail,
+                             int standalone) noexcept nogil:
+    cdef xmlNode* c_nsdecl_node
+    cdef xmlDoc* c_doc = c_node.doc
+    if write_xml_declaration and c_method == OUTPUT_METHOD_XML:
+        _writeDeclarationToBuffer(c_buffer, c_doc.version, encoding, standalone)
+
+    # comments/processing instructions before doctype declaration
+    if write_complete_document and not c_buffer.error and c_doc.intSubset:
+        _writePrevSiblings(c_buffer, <xmlNode*>c_doc.intSubset, encoding, pretty_print)
+
+    if c_doctype:
+        _writeDoctype(c_buffer, c_doctype)
+    # write internal DTD subset, preceding PIs/comments, etc.
+    if write_complete_document and not c_buffer.error:
+        if c_doctype is NULL:
+            _writeDtdToBuffer(c_buffer, c_doc, c_node.name, c_method, encoding)
+        _writePrevSiblings(c_buffer, c_node, encoding, pretty_print)
+
+    c_nsdecl_node = c_node
+    if not c_node.parent or c_node.parent.type != tree.XML_DOCUMENT_NODE:
+        # copy the node and add namespaces from parents
+        # this is required to make libxml write them
+        c_nsdecl_node = tree.xmlCopyNode(c_node, 2)
+        if not c_nsdecl_node:
+            c_buffer.error = xmlerror.XML_ERR_NO_MEMORY
+            return
+        _copyParentNamespaces(c_node, c_nsdecl_node)
+
+        c_nsdecl_node.parent = c_node.parent
+        c_nsdecl_node.children = c_node.children
+        c_nsdecl_node.last = c_node.last
+
+    # write node
+    if c_method == OUTPUT_METHOD_HTML:
+        tree.htmlNodeDumpFormatOutput(
+            c_buffer, c_doc, c_nsdecl_node, encoding, pretty_print)
+    else:
+        tree.xmlNodeDumpOutput(
+            c_buffer, c_doc, c_nsdecl_node, 0, pretty_print, encoding)
+
+    if c_nsdecl_node is not c_node:
+        # clean up
+        c_nsdecl_node.children = c_nsdecl_node.last = NULL
+        tree.xmlFreeNode(c_nsdecl_node)
+
+    if c_buffer.error:
+        return
+
+    # write tail, trailing comments, etc.
+    if with_tail:
+        _writeTail(c_buffer, c_node, encoding, c_method, pretty_print)
+    if write_complete_document:
+        _writeNextSiblings(c_buffer, c_node, encoding, pretty_print)
+    if pretty_print:
+        tree.xmlOutputBufferWrite(c_buffer, 1, "\n")
+
+cdef void _writeDeclarationToBuffer(tree.xmlOutputBuffer* c_buffer,
+                                    const_xmlChar* version, const_char* encoding,
+                                    int standalone) noexcept nogil:
+    if version is NULL:
+        version = <unsigned char*>"1.0"
+    tree.xmlOutputBufferWrite(c_buffer, 15, "<?xml version='")
+    tree.xmlOutputBufferWriteString(c_buffer, <const_char*>version)
+    tree.xmlOutputBufferWrite(c_buffer, 12, "' encoding='")
+    tree.xmlOutputBufferWriteString(c_buffer, encoding)
+    if standalone == 0:
+        tree.xmlOutputBufferWrite(c_buffer, 20, "' standalone='no'?>\n")
+    elif standalone == 1:
+        tree.xmlOutputBufferWrite(c_buffer, 21, "' standalone='yes'?>\n")
+    else:
+        tree.xmlOutputBufferWrite(c_buffer, 4, "'?>\n")
+
+cdef void _writeDtdToBuffer(tree.xmlOutputBuffer* c_buffer,
+                            xmlDoc* c_doc, const_xmlChar* c_root_name,
+                            int c_method, const_char* encoding) noexcept nogil:
+    cdef tree.xmlDtd* c_dtd
+    cdef xmlNode* c_node
+    cdef char* quotechar
+    c_dtd = c_doc.intSubset
+    if not c_dtd or not c_dtd.name:
+        return
+
+    # Name in document type declaration must match the root element tag.
+    # For XML, case sensitive match, for HTML insensitive.
+    if c_method == OUTPUT_METHOD_HTML:
+        if tree.xmlStrcasecmp(c_root_name, c_dtd.name) != 0:
+            return
+    else:
+        if tree.xmlStrcmp(c_root_name, c_dtd.name) != 0:
+            return
+
+    tree.xmlOutputBufferWrite(c_buffer, 10, "<!DOCTYPE ")
+    tree.xmlOutputBufferWriteString(c_buffer, <const_char*>c_dtd.name)
+
+    cdef const_xmlChar* public_id = c_dtd.ExternalID
+    cdef const_xmlChar* sys_url = c_dtd.SystemID
+    if public_id and public_id[0] == b'\0':
+        public_id = NULL
+    if sys_url and sys_url[0] == b'\0':
+        sys_url = NULL
+
+    if public_id:
+        tree.xmlOutputBufferWrite(c_buffer, 9, ' PUBLIC "')
+        tree.xmlOutputBufferWriteString(c_buffer, <const_char*>public_id)
+        if sys_url:
+            tree.xmlOutputBufferWrite(c_buffer, 2, '" ')
+        else:
+            tree.xmlOutputBufferWrite(c_buffer, 1, '"')
+    elif sys_url:
+        tree.xmlOutputBufferWrite(c_buffer, 8, ' SYSTEM ')
+
+    if sys_url:
+        if tree.xmlStrchr(sys_url, b'"'):
+            quotechar = '\''
+        else:
+            quotechar = '"'
+        tree.xmlOutputBufferWrite(c_buffer, 1, quotechar)
+        tree.xmlOutputBufferWriteString(c_buffer, <const_char*>sys_url)
+        tree.xmlOutputBufferWrite(c_buffer, 1, quotechar)
+
+    if (not c_dtd.entities and not c_dtd.elements and
+           not c_dtd.attributes and not c_dtd.notations and
+           not c_dtd.pentities):
+        tree.xmlOutputBufferWrite(c_buffer, 2, '>\n')
+        return
+
+    tree.xmlOutputBufferWrite(c_buffer, 3, ' [\n')
+    if c_dtd.notations and not c_buffer.error:
+        c_buf = tree.xmlBufferCreate()
+        if not c_buf:
+            c_buffer.error = xmlerror.XML_ERR_NO_MEMORY
+            return
+        tree.xmlDumpNotationTable(c_buf, <tree.xmlNotationTable*>c_dtd.notations)
+        tree.xmlOutputBufferWrite(
+            c_buffer, tree.xmlBufferLength(c_buf),
+            <const_char*>tree.xmlBufferContent(c_buf))
+        tree.xmlBufferFree(c_buf)
+    c_node = c_dtd.children
+    while c_node and not c_buffer.error:
+        tree.xmlNodeDumpOutput(c_buffer, c_node.doc, c_node, 0, 0, encoding)
+        c_node = c_node.next
+    tree.xmlOutputBufferWrite(c_buffer, 3, "]>\n")
+
+cdef void _writeTail(tree.xmlOutputBuffer* c_buffer, xmlNode* c_node,
+                     const_char* encoding, int c_method, bint pretty_print) noexcept nogil:
+    "Write the element tail."
+    c_node = c_node.next
+    while c_node and not c_buffer.error and c_node.type in (
+            tree.XML_TEXT_NODE, tree.XML_CDATA_SECTION_NODE):
+        if c_method == OUTPUT_METHOD_HTML:
+            tree.htmlNodeDumpFormatOutput(
+                c_buffer, c_node.doc, c_node, encoding, pretty_print)
+        else:
+            tree.xmlNodeDumpOutput(
+                c_buffer, c_node.doc, c_node, 0, pretty_print, encoding)
+        c_node = c_node.next
+
+cdef void _writePrevSiblings(tree.xmlOutputBuffer* c_buffer, xmlNode* c_node,
+                             const_char* encoding, bint pretty_print) noexcept nogil:
+    cdef xmlNode* c_sibling
+    if c_node.parent and _isElement(c_node.parent):
+        return
+    # we are at a root node, so add PI and comment siblings
+    c_sibling = c_node
+    while c_sibling.prev and \
+            (c_sibling.prev.type == tree.XML_PI_NODE or
+             c_sibling.prev.type == tree.XML_COMMENT_NODE):
+        c_sibling = c_sibling.prev
+    while c_sibling is not c_node and not c_buffer.error:
+        tree.xmlNodeDumpOutput(c_buffer, c_node.doc, c_sibling, 0,
+                               pretty_print, encoding)
+        if pretty_print:
+            tree.xmlOutputBufferWriteString(c_buffer, "\n")
+        c_sibling = c_sibling.next
+
+cdef void _writeNextSiblings(tree.xmlOutputBuffer* c_buffer, xmlNode* c_node,
+                             const_char* encoding, bint pretty_print) noexcept nogil:
+    cdef xmlNode* c_sibling
+    if c_node.parent and _isElement(c_node.parent):
+        return
+    # we are at a root node, so add PI and comment siblings
+    c_sibling = c_node.next
+    while not c_buffer.error and c_sibling and \
+            (c_sibling.type == tree.XML_PI_NODE or
+             c_sibling.type == tree.XML_COMMENT_NODE):
+        if pretty_print:
+            tree.xmlOutputBufferWriteString(c_buffer, "\n")
+        tree.xmlNodeDumpOutput(c_buffer, c_node.doc, c_sibling, 0,
+                               pretty_print, encoding)
+        c_sibling = c_sibling.next
+
+
+# copied and adapted from libxml2 (xmlBufAttrSerializeTxtContent())
+cdef _write_attr_string(tree.xmlOutputBuffer* buf, const char *string):
+    cdef const char *base
+    cdef const char *cur
+
+    if string == NULL:
+        return
+
+    base = cur = <const char*>string
+    while cur[0] != 0:
+        if cur[0] == b'\n':
+            if base != cur:
+                tree.xmlOutputBufferWrite(buf, cur - base, base)
+
+            tree.xmlOutputBufferWrite(buf, 5, "&#10;")
+            cur += 1
+            base = cur
+
+        elif cur[0] == b'\r':
+            if base != cur:
+                tree.xmlOutputBufferWrite(buf, cur - base, base)
+
+            tree.xmlOutputBufferWrite(buf, 5, "&#13;")
+            cur += 1
+            base = cur
+
+        elif cur[0] == b'\t':
+            if base != cur:
+                tree.xmlOutputBufferWrite(buf, cur - base, base)
+
+            tree.xmlOutputBufferWrite(buf, 4, "&#9;")
+            cur += 1
+            base = cur
+
+        elif cur[0] == b'"':
+            if base != cur:
+                tree.xmlOutputBufferWrite(buf, cur - base, base)
+
+            tree.xmlOutputBufferWrite(buf, 6, "&quot;")
+            cur += 1
+            base = cur
+
+        elif cur[0] == b'<':
+            if base != cur:
+                tree.xmlOutputBufferWrite(buf, cur - base, base)
+
+            tree.xmlOutputBufferWrite(buf, 4, "&lt;")
+            cur += 1
+            base = cur
+
+        elif cur[0] == b'>':
+            if base != cur:
+                tree.xmlOutputBufferWrite(buf, cur - base, base)
+
+            tree.xmlOutputBufferWrite(buf, 4, "&gt;")
+            cur += 1
+            base = cur
+        elif cur[0] == b'&':
+            if base != cur:
+                tree.xmlOutputBufferWrite(buf, cur - base, base)
+
+            tree.xmlOutputBufferWrite(buf, 5, "&amp;")
+            cur += 1
+            base = cur
+
+        else:
+            # Leave further encoding and escaping to the buffer encoder.
+            cur += 1
+
+    if base != cur:
+        tree.xmlOutputBufferWrite(buf, cur - base, base)
+
+
+############################################################
+# output to file-like objects
+
+cdef object io_open
+from io import open as io_open
+
+cdef object gzip
+import gzip
+
+cdef object getwriter
+from codecs import getwriter
+cdef object utf8_writer = getwriter('utf8')
+
+cdef object contextmanager
+from contextlib import contextmanager
+
+cdef object _open_utf8_file
+
+@contextmanager
+def _open_utf8_file(file, compression=0):
+    file = _getFSPathOrObject(file)
+    if _isString(file):
+        if compression:
+            with gzip.GzipFile(file, mode='wb', compresslevel=compression) as zf:
+                yield utf8_writer(zf)
+        else:
+            with io_open(file, 'w', encoding='utf8') as f:
+                yield f
+    else:
+        if compression:
+            with gzip.GzipFile(fileobj=file, mode='wb', compresslevel=compression) as zf:
+                yield utf8_writer(zf)
+        else:
+            yield utf8_writer(file)
+
+
+@cython.final
+@cython.internal
+cdef class _FilelikeWriter:
+    cdef object _filelike
+    cdef object _close_filelike
+    cdef _ExceptionContext _exc_context
+    cdef _ErrorLog error_log
+    def __cinit__(self, filelike, exc_context=None, compression=None, close=False):
+        if compression is not None and compression > 0:
+            filelike = GzipFile(
+                fileobj=filelike, mode='wb', compresslevel=compression)
+            self._close_filelike = filelike.close
+        elif close:
+            self._close_filelike = filelike.close
+        self._filelike = filelike
+        if exc_context is None:
+            self._exc_context = _ExceptionContext()
+        else:
+            self._exc_context = exc_context
+        self.error_log = _ErrorLog()
+
+    cdef tree.xmlOutputBuffer* _createOutputBuffer(
+        self, tree.xmlCharEncodingHandler* enchandler) except NULL:
+        cdef tree.xmlOutputBuffer* c_buffer
+        c_buffer = tree.xmlOutputBufferCreateIO(
+            <tree.xmlOutputWriteCallback>_writeFilelikeWriter, _closeFilelikeWriter,
+            <python.PyObject*>self, enchandler)
+        if c_buffer is NULL:
+            raise IOError, "Could not create I/O writer context."
+        return c_buffer
+
+    cdef int write(self, char* c_buffer, int size) noexcept:
+        try:
+            if self._filelike is None:
+                raise IOError, "File is already closed"
+            py_buffer = <bytes>c_buffer[:size]
+            self._filelike.write(py_buffer)
+        except:
+            size = -1
+            self._exc_context._store_raised()
+        finally:
+            return size  # and swallow any further exceptions
+
+    cdef int close(self) noexcept:
+        retval = 0
+        try:
+            if self._close_filelike is not None:
+                self._close_filelike()
+            # we should not close the file here as we didn't open it
+            self._filelike = None
+        except:
+            retval = -1
+            self._exc_context._store_raised()
+        finally:
+            return retval  # and swallow any further exceptions
+
+cdef int _writeFilelikeWriter(void* ctxt, char* c_buffer, int length) noexcept:
+    return (<_FilelikeWriter>ctxt).write(c_buffer, length)
+
+cdef int _closeFilelikeWriter(void* ctxt) noexcept:
+    return (<_FilelikeWriter>ctxt).close()
+
+cdef _tofilelike(f, _Element element, encoding, doctype, method,
+                 bint write_xml_declaration, bint write_doctype,
+                 bint pretty_print, bint with_tail, int standalone,
+                 int compression):
+    cdef _FilelikeWriter writer = None
+    cdef tree.xmlOutputBuffer* c_buffer
+    cdef tree.xmlCharEncodingHandler* enchandler
+    cdef const_char* c_enc
+    cdef const_xmlChar* c_doctype
+    cdef int error_result
+
+    c_method = _findOutputMethod(method)
+    if c_method == OUTPUT_METHOD_TEXT:
+        data = _textToString(element._c_node, encoding, with_tail)
+        if compression:
+            bytes_out = BytesIO()
+            with GzipFile(fileobj=bytes_out, mode='wb', compresslevel=compression) as gzip_file:
+                gzip_file.write(data)
+            data = bytes_out.getvalue()
+        f = _getFSPathOrObject(f)
+        if _isString(f):
+            filename8 = _encodeFilename(f)
+            with open(filename8, 'wb') as f:
+                f.write(data)
+        else:
+            f.write(data)
+        return
+
+    if encoding is None:
+        c_enc = NULL
+    else:
+        encoding = _utf8(encoding)
+        c_enc = _cstr(encoding)
+    if doctype is None:
+        c_doctype = NULL
+    else:
+        doctype = _utf8(doctype)
+        c_doctype = _xcstr(doctype)
+
+    writer = _create_output_buffer(f, c_enc, compression, &c_buffer, close=False)
+    if writer is None:
+        with nogil:
+            error_result = _serialise_node(
+                c_buffer, c_doctype, c_enc, element._c_node, c_method,
+                write_xml_declaration, write_doctype, pretty_print, with_tail, standalone)
+    else:
+        error_result = _serialise_node(
+            c_buffer, c_doctype, c_enc, element._c_node, c_method,
+            write_xml_declaration, write_doctype, pretty_print, with_tail, standalone)
+
+    if writer is not None:
+        writer._exc_context._raise_if_stored()
+    if error_result != xmlerror.XML_ERR_OK:
+        _raiseSerialisationError(error_result)
+
+
+cdef int _serialise_node(tree.xmlOutputBuffer* c_buffer, const_xmlChar* c_doctype,
+                         const_char* c_enc, xmlNode* c_node, int c_method,
+                         bint write_xml_declaration, bint write_doctype, bint pretty_print,
+                         bint with_tail, int standalone) noexcept nogil:
+    _writeNodeToBuffer(
+        c_buffer, c_node, c_enc, c_doctype, c_method,
+        write_xml_declaration, write_doctype, pretty_print, with_tail, standalone)
+    error_result = c_buffer.error
+    if error_result == xmlerror.XML_ERR_OK:
+        error_result = tree.xmlOutputBufferClose(c_buffer)
+        if error_result != -1:
+            error_result = xmlerror.XML_ERR_OK
+    else:
+        tree.xmlOutputBufferClose(c_buffer)
+    return error_result
+
+
+cdef _FilelikeWriter _create_output_buffer(
+        f, const_char* c_enc, int c_compression,
+        tree.xmlOutputBuffer** c_buffer_ret, bint close):
+    cdef tree.xmlOutputBuffer* c_buffer
+    cdef _FilelikeWriter writer
+    cdef bytes filename8
+    enchandler = tree.xmlFindCharEncodingHandler(c_enc)
+    if enchandler is NULL:
+        raise LookupError(
+            f"unknown encoding: '{c_enc.decode('UTF-8') if c_enc is not NULL else u''}'")
+    try:
+        f = _getFSPathOrObject(f)
+        if _isString(f):
+            filename8 = _encodeFilename(f)
+            if b'%' in filename8 and (
+                    # Exclude absolute Windows paths and file:// URLs.
+                    _isFilePath(<const xmlChar*>filename8) not in (NO_FILE_PATH, ABS_WIN_FILE_PATH)
+                    or filename8[:7].lower() == b'file://'):
+                # A file path (not a URL) containing the '%' URL escape character.
+                # libxml2 uses URL-unescaping on these, so escape the path before passing it in.
+                filename8 = filename8.replace(b'%', b'%25')
+            c_buffer = tree.xmlOutputBufferCreateFilename(
+                _cstr(filename8), enchandler, c_compression)
+            if c_buffer is NULL:
+                python.PyErr_SetFromErrno(IOError)  # raises IOError
+            writer = None
+        elif hasattr(f, 'write'):
+            writer = _FilelikeWriter(f, compression=c_compression, close=close)
+            c_buffer = writer._createOutputBuffer(enchandler)
+        else:
+            raise TypeError(
+                f"File or filename expected, got '{python._fqtypename(f).decode('UTF-8')}'")
+    except:
+        tree.xmlCharEncCloseFunc(enchandler)
+        raise
+    c_buffer_ret[0] = c_buffer
+    return writer
+
+cdef xmlChar **_convert_ns_prefixes(tree.xmlDict* c_dict, ns_prefixes) except NULL:
+    cdef size_t i, num_ns_prefixes = len(ns_prefixes)
+    # Need to allocate one extra memory block to handle last NULL entry
+    c_ns_prefixes = <xmlChar **>python.lxml_malloc(num_ns_prefixes + 1, sizeof(xmlChar*))
+    if not c_ns_prefixes:
+        raise MemoryError()
+    i = 0
+    try:
+        for prefix in ns_prefixes:
+             prefix_utf = _utf8(prefix)
+             c_prefix = tree.xmlDictExists(c_dict, _xcstr(prefix_utf), len(prefix_utf))
+             if c_prefix:
+                 # unknown prefixes do not need to get serialised
+                 c_ns_prefixes[i] = <xmlChar*>c_prefix
+                 i += 1
+    except:
+        python.lxml_free(c_ns_prefixes)
+        raise
+
+    c_ns_prefixes[i] = NULL  # append end marker
+    return c_ns_prefixes
+
+cdef _tofilelikeC14N(f, _Element element, bint exclusive, bint with_comments,
+                     int compression, inclusive_ns_prefixes):
+    cdef _FilelikeWriter writer = None
+    cdef tree.xmlOutputBuffer* c_buffer
+    cdef xmlChar **c_inclusive_ns_prefixes = NULL
+    cdef char* c_filename
+    cdef xmlDoc* c_base_doc
+    cdef xmlDoc* c_doc
+    cdef int bytes_count, error = 0
+
+    c_base_doc = element._c_node.doc
+    c_doc = _fakeRootDoc(c_base_doc, element._c_node)
+    try:
+        c_inclusive_ns_prefixes = (
+            _convert_ns_prefixes(c_doc.dict, inclusive_ns_prefixes)
+            if inclusive_ns_prefixes else NULL)
+
+        f = _getFSPathOrObject(f)
+        if _isString(f):
+            filename8 = _encodeFilename(f)
+            c_filename = _cstr(filename8)
+            with nogil:
+                error = c14n.xmlC14NDocSave(
+                    c_doc, NULL, exclusive, c_inclusive_ns_prefixes,
+                    with_comments, c_filename, compression)
+        elif hasattr(f, 'write'):
+            writer   = _FilelikeWriter(f, compression=compression)
+            c_buffer = writer._createOutputBuffer(NULL)
+            try:
+                with writer.error_log:
+                    bytes_count = c14n.xmlC14NDocSaveTo(
+                        c_doc, NULL, exclusive, c_inclusive_ns_prefixes,
+                        with_comments, c_buffer)
+            finally:
+                error = tree.xmlOutputBufferClose(c_buffer)
+            if bytes_count < 0:
+                error = bytes_count
+            elif error != -1:
+                error = xmlerror.XML_ERR_OK
+        else:
+            raise TypeError(f"File or filename expected, got '{python._fqtypename(f).decode('UTF-8')}'")
+    finally:
+        _destroyFakeDoc(c_base_doc, c_doc)
+        if c_inclusive_ns_prefixes is not NULL:
+            python.lxml_free(c_inclusive_ns_prefixes)
+
+    if writer is not None:
+        writer._exc_context._raise_if_stored()
+
+    if error < 0:
+        message = "C14N failed"
+        if writer is not None:
+            errors = writer.error_log
+            if len(errors):
+                message = errors[0].message
+        raise C14NError(message)
+
+
+# C14N 2.0
+
+def canonicalize(xml_data=None, *, out=None, from_file=None, **options):
+    """Convert XML to its C14N 2.0 serialised form.
+
+    If *out* is provided, it must be a file or file-like object that receives
+    the serialised canonical XML output (text, not bytes) through its ``.write()``
+    method.  To write to a file, open it in text mode with encoding "utf-8".
+    If *out* is not provided, this function returns the output as text string.
+
+    Either *xml_data* (an XML string, tree or Element) or *file*
+    (a file path or file-like object) must be provided as input.
+
+    The configuration options are the same as for the ``C14NWriterTarget``.
+    """
+    if xml_data is None and from_file is None:
+        raise ValueError("Either 'xml_data' or 'from_file' must be provided as input")
+
+    sio = None
+    if out is None:
+        sio = out = StringIO()
+
+    target = C14NWriterTarget(out.write, **options)
+
+    if xml_data is not None and not isinstance(xml_data, basestring):
+        _tree_to_target(xml_data, target)
+        return sio.getvalue() if sio is not None else None
+
+    cdef _FeedParser parser = XMLParser(
+        target=target,
+        attribute_defaults=True,
+        collect_ids=False,
+    )
+
+    if xml_data is not None:
+        parser.feed(xml_data)
+        parser.close()
+    elif from_file is not None:
+        try:
+            _parseDocument(from_file, parser, base_url=None)
+        except _TargetParserResult:
+            pass
+
+    return sio.getvalue() if sio is not None else None
+
+
+cdef _tree_to_target(element, target):
+    for event, elem in iterwalk(element, events=('start', 'end', 'start-ns', 'comment', 'pi')):
+        text = None
+        if event == 'start':
+            target.start(elem.tag, elem.attrib)
+            text = elem.text
+        elif event == 'end':
+            target.end(elem.tag)
+            text = elem.tail
+        elif event == 'start-ns':
+            target.start_ns(*elem)
+            continue
+        elif event == 'comment':
+            target.comment(elem.text)
+            text = elem.tail
+        elif event == 'pi':
+            target.pi(elem.target, elem.text)
+            text = elem.tail
+        if text:
+            target.data(text)
+    return target.close()
+
+
+cdef object _looks_like_prefix_name = re.compile(r'^\w+:\w+$', re.UNICODE).match
+
+
+cdef class C14NWriterTarget:
+    """
+    Canonicalization writer target for the XMLParser.
+
+    Serialises parse events to XML C14N 2.0.
+
+    Configuration options:
+
+    - *with_comments*: set to true to include comments
+    - *strip_text*: set to true to strip whitespace before and after text content
+    - *rewrite_prefixes*: set to true to replace namespace prefixes by "n{number}"
+    - *qname_aware_tags*: a set of qname aware tag names in which prefixes
+                          should be replaced in text content
+    - *qname_aware_attrs*: a set of qname aware attribute names in which prefixes
+                           should be replaced in text content
+    - *exclude_attrs*: a set of attribute names that should not be serialised
+    - *exclude_tags*: a set of tag names that should not be serialised
+    """
+    cdef object _write
+    cdef list _data
+    cdef set _qname_aware_tags
+    cdef object _find_qname_aware_attrs
+    cdef list _declared_ns_stack
+    cdef list _ns_stack
+    cdef dict _prefix_map
+    cdef list _preserve_space
+    cdef tuple _pending_start
+    cdef set _exclude_tags
+    cdef set _exclude_attrs
+    cdef Py_ssize_t _ignored_depth
+    cdef bint _with_comments
+    cdef bint _strip_text
+    cdef bint _rewrite_prefixes
+    cdef bint _root_seen
+    cdef bint _root_done
+
+    def __init__(self, write, *,
+                 with_comments=False, strip_text=False, rewrite_prefixes=False,
+                 qname_aware_tags=None, qname_aware_attrs=None,
+                 exclude_attrs=None, exclude_tags=None):
+        self._write = write
+        self._data = []
+        self._with_comments = with_comments
+        self._strip_text = strip_text
+        self._exclude_attrs = set(exclude_attrs) if exclude_attrs else None
+        self._exclude_tags = set(exclude_tags) if exclude_tags else None
+
+        self._rewrite_prefixes = rewrite_prefixes
+        if qname_aware_tags:
+            self._qname_aware_tags = set(qname_aware_tags)
+        else:
+            self._qname_aware_tags = None
+        if qname_aware_attrs:
+            self._find_qname_aware_attrs = set(qname_aware_attrs).intersection
+        else:
+            self._find_qname_aware_attrs = None
+
+        # Stack with globally and newly declared namespaces as (uri, prefix) pairs.
+        self._declared_ns_stack = [[
+            ("http://www.w3.org/XML/1998/namespace", "xml"),
+        ]]
+        # Stack with user declared namespace prefixes as (uri, prefix) pairs.
+        self._ns_stack = []
+        if not rewrite_prefixes:
+            self._ns_stack.append(_DEFAULT_NAMESPACE_PREFIXES_ITEMS)
+        self._ns_stack.append([])
+        self._prefix_map = {}
+        self._preserve_space = [False]
+        self._pending_start = None
+        self._ignored_depth = 0
+        self._root_seen = False
+        self._root_done = False
+
+    def _iter_namespaces(self, ns_stack):
+        for namespaces in reversed(ns_stack):
+            if namespaces:  # almost no element declares new namespaces
+                yield from namespaces
+
+    cdef _resolve_prefix_name(self, prefixed_name):
+        prefix, name = prefixed_name.split(':', 1)
+        for uri, p in self._iter_namespaces(self._ns_stack):
+            if p == prefix:
+                return f'{{{uri}}}{name}'
+        raise ValueError(f'Prefix {prefix} of QName "{prefixed_name}" is not declared in scope')
+
+    cdef _qname(self, qname, uri=None):
+        if uri is None:
+            uri, tag = qname[1:].rsplit('}', 1) if qname[:1] == '{' else ('', qname)
+        else:
+            tag = qname
+
+        prefixes_seen = set()
+        for u, prefix in self._iter_namespaces(self._declared_ns_stack):
+            if u == uri and prefix not in prefixes_seen:
+                return f'{prefix}:{tag}' if prefix else tag, tag, uri
+            prefixes_seen.add(prefix)
+
+        # Not declared yet => add new declaration.
+        if self._rewrite_prefixes:
+            if uri in self._prefix_map:
+                prefix = self._prefix_map[uri]
+            else:
+                prefix = self._prefix_map[uri] = f'n{len(self._prefix_map)}'
+            self._declared_ns_stack[-1].append((uri, prefix))
+            return f'{prefix}:{tag}', tag, uri
+
+        if not uri and '' not in prefixes_seen:
+            # No default namespace declared => no prefix needed.
+            return tag, tag, uri
+
+        for u, prefix in self._iter_namespaces(self._ns_stack):
+            if u == uri:
+                self._declared_ns_stack[-1].append((uri, prefix))
+                return f'{prefix}:{tag}' if prefix else tag, tag, uri
+
+        if not uri:
+            # As soon as a default namespace is defined,
+            # anything that has no namespace (and thus, no prefix) goes there.
+            return tag, tag, uri
+
+        raise ValueError(f'Namespace "{uri}" of name "{tag}" is not declared in scope')
+
+    def data(self, data):
+        if not self._ignored_depth:
+            self._data.append(data)
+
+    cdef _flush(self):
+        cdef unicode data = ''.join(self._data)
+        del self._data[:]
+        if self._strip_text and not self._preserve_space[-1]:
+            data = data.strip()
+        if self._pending_start is not None:
+            (tag, attrs, new_namespaces), self._pending_start = self._pending_start, None
+            qname_text = data if ':' in data and _looks_like_prefix_name(data) else None
+            self._start(tag, attrs, new_namespaces, qname_text)
+            if qname_text is not None:
+                return
+        if data and self._root_seen:
+            self._write(_escape_cdata_c14n(data))
+
+    def start_ns(self, prefix, uri):
+        if self._ignored_depth:
+            return
+        # we may have to resolve qnames in text content
+        if self._data:
+            self._flush()
+        self._ns_stack[-1].append((uri, prefix))
+
+    def start(self, tag, attrs):
+        if self._exclude_tags is not None and (
+                self._ignored_depth or tag in self._exclude_tags):
+            self._ignored_depth += 1
+            return
+        if self._data:
+            self._flush()
+
+        new_namespaces = []
+        self._declared_ns_stack.append(new_namespaces)
+
+        if self._qname_aware_tags is not None and tag in self._qname_aware_tags:
+            # Need to parse text first to see if it requires a prefix declaration.
+            self._pending_start = (tag, attrs, new_namespaces)
+            return
+        self._start(tag, attrs, new_namespaces)
+
+    cdef _start(self, tag, attrs, new_namespaces, qname_text=None):
+        if self._exclude_attrs is not None and attrs:
+            attrs = {k: v for k, v in attrs.items() if k not in self._exclude_attrs}
+
+        qnames = {tag, *attrs}
+        resolved_names = {}
+
+        # Resolve prefixes in attribute and tag text.
+        if qname_text is not None:
+            qname = resolved_names[qname_text] = self._resolve_prefix_name(qname_text)
+            qnames.add(qname)
+        if self._find_qname_aware_attrs is not None and attrs:
+            qattrs = self._find_qname_aware_attrs(attrs)
+            if qattrs:
+                for attr_name in qattrs:
+                    value = attrs[attr_name]
+                    if _looks_like_prefix_name(value):
+                        qname = resolved_names[value] = self._resolve_prefix_name(value)
+                        qnames.add(qname)
+            else:
+                qattrs = None
+        else:
+            qattrs = None
+
+        # Assign prefixes in lexicographical order of used URIs.
+        parsed_qnames = {n: self._qname(n) for n in sorted(
+            qnames, key=lambda n: n.split('}', 1))}
+
+        # Write namespace declarations in prefix order ...
+        if new_namespaces:
+            attr_list = [
+                ('xmlns:' + prefix if prefix else 'xmlns', uri)
+                for uri, prefix in new_namespaces
+            ]
+            attr_list.sort()
+        else:
+            # almost always empty
+            attr_list = []
+
+        # ... followed by attributes in URI+name order
+        if attrs:
+            for k, v in sorted(attrs.items()):
+                if qattrs is not None and k in qattrs and v in resolved_names:
+                    v = parsed_qnames[resolved_names[v]][0]
+                attr_qname, attr_name, uri = parsed_qnames[k]
+                # No prefix for attributes in default ('') namespace.
+                attr_list.append((attr_qname if uri else attr_name, v))
+
+        # Honour xml:space attributes.
+        space_behaviour = attrs.get('{http://www.w3.org/XML/1998/namespace}space')
+        self._preserve_space.append(
+            space_behaviour == 'preserve' if space_behaviour
+            else self._preserve_space[-1])
+
+        # Write the tag.
+        write = self._write
+        write('<' + parsed_qnames[tag][0])
+        if attr_list:
+            write(''.join([f' {k}="{_escape_attrib_c14n(v)}"' for k, v in attr_list]))
+        write('>')
+
+        # Write the resolved qname text content.
+        if qname_text is not None:
+            write(_escape_cdata_c14n(parsed_qnames[resolved_names[qname_text]][0]))
+
+        self._root_seen = True
+        self._ns_stack.append([])
+
+    def end(self, tag):
+        if self._ignored_depth:
+            self._ignored_depth -= 1
+            return
+        if self._data:
+            self._flush()
+        self._write(f'</{self._qname(tag)[0]}>')
+        self._preserve_space.pop()
+        self._root_done = len(self._preserve_space) == 1
+        self._declared_ns_stack.pop()
+        self._ns_stack.pop()
+
+    def comment(self, text):
+        if not self._with_comments:
+            return
+        if self._ignored_depth:
+            return
+        if self._root_done:
+            self._write('\n')
+        elif self._root_seen and self._data:
+            self._flush()
+        self._write(f'<!--{_escape_cdata_c14n(text)}-->')
+        if not self._root_seen:
+            self._write('\n')
+
+    def pi(self, target, data):
+        if self._ignored_depth:
+            return
+        if self._root_done:
+            self._write('\n')
+        elif self._root_seen and self._data:
+            self._flush()
+        self._write(
+            f'<?{target} {_escape_cdata_c14n(data)}?>' if data else f'<?{target}?>')
+        if not self._root_seen:
+            self._write('\n')
+
+    def close(self):
+        return None
+
+
+cdef _raise_serialization_error(text):
+    raise TypeError("cannot serialize %r (type %s)" % (text, type(text).__name__))
+
+
+cdef unicode _escape_cdata_c14n(stext):
+    # escape character data
+    cdef unicode text
+    cdef Py_UCS4 ch
+    cdef Py_ssize_t start = 0, pos = 0
+    cdef list substrings = None
+    try:
+        text = unicode(stext)
+    except (TypeError, AttributeError):
+        return _raise_serialization_error(stext)
+
+    for pos, ch in enumerate(text):
+        if ch == '&':
+            escape = '&amp;'
+        elif ch == '<':
+            escape = '&lt;'
+        elif ch == '>':
+            escape = '&gt;'
+        elif ch == '\r':
+            escape = '&#xD;'
+        else:
+            continue
+
+        if substrings is None:
+            substrings = []
+        if pos > start:
+            substrings.append(text[start:pos])
+        substrings.append(escape)
+        start = pos + 1
+
+    if substrings is None:
+        return text
+    if pos >= start:
+        substrings.append(text[start:pos+1])
+    return ''.join(substrings)
+
+
+cdef unicode _escape_attrib_c14n(stext):
+    # escape attribute value
+    cdef unicode text
+    cdef Py_UCS4 ch
+    cdef Py_ssize_t start = 0, pos = 0
+    cdef list substrings = None
+    try:
+        text = unicode(stext)
+    except (TypeError, AttributeError):
+        return _raise_serialization_error(stext)
+
+    for pos, ch in enumerate(text):
+        if ch == '&':
+            escape = '&amp;'
+        elif ch == '<':
+            escape = '&lt;'
+        elif ch == '"':
+            escape = '&quot;'
+        elif ch == '\t':
+            escape = '&#x9;'
+        elif ch == '\n':
+            escape = '&#xA;'
+        elif ch == '\r':
+            escape = '&#xD;'
+        else:
+            continue
+
+        if substrings is None:
+            substrings = []
+        if pos > start:
+            substrings.append(text[start:pos])
+        substrings.append(escape)
+        start = pos + 1
+
+    if substrings is None:
+        return text
+    if pos >= start:
+        substrings.append(text[start:pos+1])
+    return ''.join(substrings)
+
+
+# incremental serialisation
+
+cdef class xmlfile:
+    """xmlfile(self, output_file, encoding=None, compression=None, close=False, buffered=True)
+
+    A simple mechanism for incremental XML serialisation.
+
+    Usage example::
+
+         with xmlfile("somefile.xml", encoding='utf-8') as xf:
+             xf.write_declaration(standalone=True)
+             xf.write_doctype('<!DOCTYPE root SYSTEM "some.dtd">')
+
+             # generate an element (the root element)
+             with xf.element('root'):
+                  # write a complete Element into the open root element
+                  xf.write(etree.Element('test'))
+
+                  # generate and write more Elements, e.g. through iterparse
+                  for element in generate_some_elements():
+                      # serialise generated elements into the XML file
+                      xf.write(element)
+
+                  # or write multiple Elements or strings at once
+                  xf.write(etree.Element('start'), "text", etree.Element('end'))
+
+    If 'output_file' is a file(-like) object, passing ``close=True`` will
+    close it when exiting the context manager.  By default, it is left
+    to the owner to do that.  When a file path is used, lxml will take care
+    of opening and closing the file itself.  Also, when a compression level
+    is set, lxml will deliberately close the file to make sure all data gets
+    compressed and written.
+
+    Setting ``buffered=False`` will flush the output after each operation,
+    such as opening or closing an ``xf.element()`` block or calling
+    ``xf.write()``.  Alternatively, calling ``xf.flush()`` can be used to
+    explicitly flush any pending output when buffering is enabled.
+    """
+    cdef object output_file
+    cdef bytes encoding
+    cdef _IncrementalFileWriter writer
+    cdef _AsyncIncrementalFileWriter async_writer
+    cdef int compresslevel
+    cdef bint close
+    cdef bint buffered
+    cdef int method
+
+    def __init__(self, output_file not None, encoding=None, compression=None,
+                 close=False, buffered=True):
+        self.output_file = output_file
+        self.encoding = _utf8orNone(encoding)
+        self.compresslevel = compression or 0
+        self.close = close
+        self.buffered = buffered
+        self.method = OUTPUT_METHOD_XML
+
+    def __enter__(self):
+        assert self.output_file is not None
+        self.writer = _IncrementalFileWriter(
+            self.output_file, self.encoding, self.compresslevel,
+            self.close, self.buffered, self.method)
+        return self.writer
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        if self.writer is not None:
+            old_writer, self.writer = self.writer, None
+            raise_on_error = exc_type is None
+            old_writer._close(raise_on_error)
+            if self.close:
+                self.output_file = None
+
+    async def __aenter__(self):
+        assert self.output_file is not None
+        if isinstance(self.output_file, basestring):
+            raise TypeError("Cannot asynchronously write to a plain file")
+        if not hasattr(self.output_file, 'write'):
+            raise TypeError("Output file needs an async .write() method")
+        self.async_writer = _AsyncIncrementalFileWriter(
+            self.output_file, self.encoding, self.compresslevel,
+            self.close, self.buffered, self.method)
+        return self.async_writer
+
+    async def __aexit__(self, exc_type, exc_val, exc_tb):
+        if self.async_writer is not None:
+            old_writer, self.async_writer = self.async_writer, None
+            raise_on_error = exc_type is None
+            await old_writer._close(raise_on_error)
+            if self.close:
+                self.output_file = None
+
+
+cdef class htmlfile(xmlfile):
+    """htmlfile(self, output_file, encoding=None, compression=None, close=False, buffered=True)
+
+    A simple mechanism for incremental HTML serialisation.  Works the same as
+    xmlfile.
+    """
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.method = OUTPUT_METHOD_HTML
+
+
+cdef enum _IncrementalFileWriterStatus:
+    WRITER_STARTING = 0
+    WRITER_DECL_WRITTEN = 1
+    WRITER_DTD_WRITTEN = 2
+    WRITER_IN_ELEMENT = 3
+    WRITER_FINISHED = 4
+
+
+@cython.final
+@cython.internal
+cdef class _IncrementalFileWriter:
+    cdef tree.xmlOutputBuffer* _c_out
+    cdef bytes _encoding
+    cdef const_char* _c_encoding
+    cdef _FilelikeWriter _target
+    cdef list _element_stack
+    cdef int _status
+    cdef int _method
+    cdef bint _buffered
+
+    def __cinit__(self, outfile, bytes encoding, int compresslevel, bint close,
+                  bint buffered, int method):
+        self._status = WRITER_STARTING
+        self._element_stack = []
+        if encoding is None:
+            # We always need a document encoding to make the attribute serialisation
+            # of libxml2 identical to ours.
+            encoding = b'ASCII'
+        self._encoding = encoding
+        self._c_encoding = _cstr(encoding)
+        self._buffered = buffered
+        self._target = _create_output_buffer(
+            outfile, self._c_encoding, compresslevel, &self._c_out, close)
+        self._method = method
+
+    def __dealloc__(self):
+        if self._c_out is not NULL:
+            tree.xmlOutputBufferClose(self._c_out)
+
+    def write_declaration(self, version=None, standalone=None, doctype=None):
+        """write_declaration(self, version=None, standalone=None, doctype=None)
+
+        Write an XML declaration and (optionally) a doctype into the file.
+        """
+        assert self._c_out is not NULL
+        cdef const_xmlChar* c_version
+        cdef int c_standalone
+        if self._method != OUTPUT_METHOD_XML:
+            raise LxmlSyntaxError("only XML documents have declarations")
+        if self._status >= WRITER_DECL_WRITTEN:
+            raise LxmlSyntaxError("XML declaration already written")
+        version = _utf8orNone(version)
+        c_version = _xcstr(version) if version is not None else NULL
+        doctype = _utf8orNone(doctype)
+        if standalone is None:
+            c_standalone = -1
+        else:
+            c_standalone = 1 if standalone else 0
+        _writeDeclarationToBuffer(self._c_out, c_version, self._c_encoding, c_standalone)
+        if doctype is not None:
+            _writeDoctype(self._c_out, _xcstr(doctype))
+            self._status = WRITER_DTD_WRITTEN
+        else:
+            self._status = WRITER_DECL_WRITTEN
+        if not self._buffered:
+            tree.xmlOutputBufferFlush(self._c_out)
+        self._handle_error(self._c_out.error)
+
+    def write_doctype(self, doctype):
+        """write_doctype(self, doctype)
+
+        Writes the given doctype declaration verbatimly into the file.
+        """
+        assert self._c_out is not NULL
+        if doctype is None:
+            return
+        if self._status >= WRITER_DTD_WRITTEN:
+            raise LxmlSyntaxError("DOCTYPE already written or cannot write it here")
+        doctype = _utf8(doctype)
+        _writeDoctype(self._c_out, _xcstr(doctype))
+        self._status = WRITER_DTD_WRITTEN
+        if not self._buffered:
+            tree.xmlOutputBufferFlush(self._c_out)
+        self._handle_error(self._c_out.error)
+
+    def method(self, method):
+        """method(self, method)
+
+        Returns a context manager that overrides and restores the output method.
+        method is one of (None, 'xml', 'html') where None means 'xml'.
+        """
+        assert self._c_out is not NULL
+        c_method = self._method if method is None else _findOutputMethod(method)
+        return _MethodChanger(self, c_method)
+
+    def element(self, tag, attrib=None, nsmap=None, method=None, **_extra):
+        """element(self, tag, attrib=None, nsmap=None, method, **_extra)
+
+        Returns a context manager that writes an opening and closing tag.
+        method is one of (None, 'xml', 'html') where None means 'xml'.
+        """
+        assert self._c_out is not NULL
+        attributes = []
+        if attrib is not None:
+            for name, value in _iter_attrib(attrib):
+                if name not in _extra:
+                    ns, name = _getNsTag(name)
+                    attributes.append((ns, name, _utf8(value)))
+        if _extra:
+            for name, value in _extra.iteritems():
+                ns, name = _getNsTag(name)
+                attributes.append((ns, name, _utf8(value)))
+        reversed_nsmap = {}
+        if nsmap:
+            for prefix, ns in nsmap.items():
+                if prefix is not None:
+                    prefix = _utf8(prefix)
+                    _prefixValidOrRaise(prefix)
+                reversed_nsmap[_utf8(ns)] = prefix
+        ns, name = _getNsTag(tag)
+
+        c_method = self._method if method is None else _findOutputMethod(method)
+
+        return _FileWriterElement(self, (ns, name, attributes, reversed_nsmap), c_method)
+
+    cdef _write_qname(self, bytes name, bytes prefix):
+        if prefix:  # empty bytes for no prefix (not None to allow sorting)
+            tree.xmlOutputBufferWrite(self._c_out, len(prefix), _cstr(prefix))
+            tree.xmlOutputBufferWrite(self._c_out, 1, ':')
+        tree.xmlOutputBufferWrite(self._c_out, len(name), _cstr(name))
+
+    cdef _write_start_element(self, element_config):
+        if self._status > WRITER_IN_ELEMENT:
+            raise LxmlSyntaxError("cannot append trailing element to complete XML document")
+        ns, name, attributes, nsmap = element_config
+        flat_namespace_map, new_namespaces = self._collect_namespaces(nsmap)
+        prefix = self._find_prefix(ns, flat_namespace_map, new_namespaces)
+        tree.xmlOutputBufferWrite(self._c_out, 1, '<')
+        self._write_qname(name, prefix)
+
+        self._write_attributes_and_namespaces(
+            attributes, flat_namespace_map, new_namespaces)
+
+        tree.xmlOutputBufferWrite(self._c_out, 1, '>')
+        if not self._buffered:
+            tree.xmlOutputBufferFlush(self._c_out)
+        self._handle_error(self._c_out.error)
+
+        self._element_stack.append((ns, name, prefix, flat_namespace_map))
+        self._status = WRITER_IN_ELEMENT
+
+    cdef _write_attributes_and_namespaces(self, list attributes,
+                                          dict flat_namespace_map,
+                                          list new_namespaces):
+        if attributes:
+            # _find_prefix() may append to new_namespaces => build them first
+            attributes = [
+                (self._find_prefix(ns, flat_namespace_map, new_namespaces), name, value)
+                for ns, name, value in attributes ]
+        if new_namespaces:
+            new_namespaces.sort()
+            self._write_attributes_list(new_namespaces)
+        if attributes:
+            self._write_attributes_list(attributes)
+
+    cdef _write_attributes_list(self, list attributes):
+        for prefix, name, value in attributes:
+            tree.xmlOutputBufferWrite(self._c_out, 1, ' ')
+            self._write_qname(name, prefix)
+            tree.xmlOutputBufferWrite(self._c_out, 2, '="')
+            _write_attr_string(self._c_out, _cstr(value))
+
+            tree.xmlOutputBufferWrite(self._c_out, 1, '"')
+
+    cdef _write_end_element(self, element_config):
+        if self._status != WRITER_IN_ELEMENT:
+            raise LxmlSyntaxError("not in an element")
+        if not self._element_stack or self._element_stack[-1][:2] != element_config[:2]:
+            raise LxmlSyntaxError("inconsistent exit action in context manager")
+
+        # If previous write operations failed, the context manager exit might still call us.
+        # That is ok, but we stop writing closing tags and handling errors in that case.
+        # For all non-I/O errors, we continue writing closing tags if we can.
+        ok_to_write = self._c_out.error == xmlerror.XML_ERR_OK
+
+        name, prefix = self._element_stack.pop()[1:3]
+        if ok_to_write:
+            tree.xmlOutputBufferWrite(self._c_out, 2, '</')
+            self._write_qname(name, prefix)
+            tree.xmlOutputBufferWrite(self._c_out, 1, '>')
+
+        if not self._element_stack:
+            self._status = WRITER_FINISHED
+        if ok_to_write:
+            if not self._buffered:
+                tree.xmlOutputBufferFlush(self._c_out)
+            self._handle_error(self._c_out.error)
+
+    cdef _find_prefix(self, bytes href, dict flat_namespaces_map, list new_namespaces):
+        if href is None:
+            return None
+        if href in flat_namespaces_map:
+            return flat_namespaces_map[href]
+        # need to create a new prefix
+        prefixes = flat_namespaces_map.values()
+        i = 0
+        while True:
+            prefix = _utf8('ns%d' % i)
+            if prefix not in prefixes:
+                new_namespaces.append((b'xmlns', prefix, href))
+                flat_namespaces_map[href] = prefix
+                return prefix
+            i += 1
+
+    cdef _collect_namespaces(self, dict nsmap):
+        new_namespaces = []
+        flat_namespaces_map = {}
+        for ns, prefix in nsmap.iteritems():
+            flat_namespaces_map[ns] = prefix
+            if prefix is None:
+                # use empty bytes rather than None to allow sorting
+                new_namespaces.append((b'', b'xmlns', ns))
+            else:
+                new_namespaces.append((b'xmlns', prefix, ns))
+        # merge in flat namespace map of parent
+        if self._element_stack:
+            for ns, prefix in (<dict>self._element_stack[-1][-1]).iteritems():
+                if flat_namespaces_map.get(ns) is None:
+                    # unknown or empty prefix => prefer a 'real' prefix
+                    flat_namespaces_map[ns] = prefix
+        return flat_namespaces_map, new_namespaces
+
+    def write(self, *args, bint with_tail=True, bint pretty_print=False, method=None):
+        """write(self, *args, with_tail=True, pretty_print=False, method=None)
+
+        Write subtrees or strings into the file.
+
+        If method is not None, it should be one of ('html', 'xml', 'text')
+        to temporarily override the output method.
+        """
+        assert self._c_out is not NULL
+        c_method = self._method if method is None else _findOutputMethod(method)
+
+        for content in args:
+            if _isString(content):
+                if self._status != WRITER_IN_ELEMENT:
+                    if self._status > WRITER_IN_ELEMENT or content.strip():
+                        raise LxmlSyntaxError("not in an element")
+                bstring = _utf8(content)
+                if not bstring:
+                    continue
+
+                ns, name, _, _ = self._element_stack[-1]
+                if (c_method == OUTPUT_METHOD_HTML and
+                        ns in (None, b'http://www.w3.org/1999/xhtml') and
+                        name in (b'script', b'style')):
+                    tree.xmlOutputBufferWrite(self._c_out, len(bstring), _cstr(bstring))
+
+                else:
+                    tree.xmlOutputBufferWriteEscape(self._c_out, _xcstr(bstring), NULL)
+
+            elif iselement(content):
+                if self._status > WRITER_IN_ELEMENT:
+                    raise LxmlSyntaxError("cannot append trailing element to complete XML document")
+                _writeNodeToBuffer(self._c_out, (<_Element>content)._c_node,
+                                   self._c_encoding, NULL, c_method,
+                                   False, False, pretty_print, with_tail, False)
+                if (<_Element>content)._c_node.type == tree.XML_ELEMENT_NODE:
+                    if not self._element_stack:
+                        self._status = WRITER_FINISHED
+
+            elif content is not None:
+                raise TypeError(
+                    f"got invalid input value of type {type(content)}, expected string or Element")
+            self._handle_error(self._c_out.error)
+        if not self._buffered:
+            tree.xmlOutputBufferFlush(self._c_out)
+            self._handle_error(self._c_out.error)
+
+    def flush(self):
+        """flush(self)
+
+        Write any pending content of the current output buffer to the stream.
+        """
+        assert self._c_out is not NULL
+        tree.xmlOutputBufferFlush(self._c_out)
+        self._handle_error(self._c_out.error)
+
+    cdef _close(self, bint raise_on_error):
+        if raise_on_error:
+            if self._status < WRITER_IN_ELEMENT:
+                raise LxmlSyntaxError("no content written")
+            if self._element_stack:
+                raise LxmlSyntaxError("pending open tags on close")
+        error_result = self._c_out.error
+        if error_result == xmlerror.XML_ERR_OK:
+            error_result = tree.xmlOutputBufferClose(self._c_out)
+            if error_result != -1:
+                error_result = xmlerror.XML_ERR_OK
+        else:
+            tree.xmlOutputBufferClose(self._c_out)
+        self._status = WRITER_FINISHED
+        self._c_out = NULL
+        del self._element_stack[:]
+        if raise_on_error:
+            self._handle_error(error_result)
+
+    cdef _handle_error(self, int error_result):
+        if error_result != xmlerror.XML_ERR_OK:
+            if self._target is not None:
+                self._target._exc_context._raise_if_stored()
+            _raiseSerialisationError(error_result)
+
+
+@cython.final
+@cython.internal
+cdef class _AsyncDataWriter:
+    cdef list _data
+    def __cinit__(self):
+        self._data = []
+
+    cdef bytes collect(self):
+        data = b''.join(self._data)
+        del self._data[:]
+        return data
+
+    def write(self, data):
+        self._data.append(data)
+
+    def close(self):
+        pass
+
+
+@cython.final
+@cython.internal
+cdef class _AsyncIncrementalFileWriter:
+    cdef _IncrementalFileWriter _writer
+    cdef _AsyncDataWriter _buffer
+    cdef object _async_outfile
+    cdef int _flush_after_writes
+    cdef bint _should_close
+    cdef bint _buffered
+
+    def __cinit__(self, async_outfile, bytes encoding, int compresslevel, bint close,
+                  bint buffered, int method):
+        self._flush_after_writes = 20
+        self._async_outfile = async_outfile
+        self._should_close = close
+        self._buffered = buffered
+        self._buffer = _AsyncDataWriter()
+        self._writer = _IncrementalFileWriter(
+            self._buffer, encoding, compresslevel, close=True, buffered=False, method=method)
+
+    cdef bytes _flush(self):
+        if not self._buffered or len(self._buffer._data) > self._flush_after_writes:
+            return self._buffer.collect()
+        return None
+
+    async def flush(self):
+        self._writer.flush()
+        data = self._buffer.collect()
+        if data:
+            await self._async_outfile.write(data)
+
+    async def write_declaration(self, version=None, standalone=None, doctype=None):
+        self._writer.write_declaration(version, standalone, doctype)
+        data = self._flush()
+        if data:
+            await self._async_outfile.write(data)
+
+    async def write_doctype(self, doctype):
+        self._writer.write_doctype(doctype)
+        data = self._flush()
+        if data:
+            await self._async_outfile.write(data)
+
+    async def write(self, *args, with_tail=True, pretty_print=False, method=None):
+        self._writer.write(*args, with_tail=with_tail, pretty_print=pretty_print, method=method)
+        data = self._flush()
+        if data:
+            await self._async_outfile.write(data)
+
+    def method(self, method):
+        return self._writer.method(method)
+
+    def element(self, tag, attrib=None, nsmap=None, method=None, **_extra):
+        element_writer = self._writer.element(tag, attrib, nsmap, method, **_extra)
+        return _AsyncFileWriterElement(element_writer, self)
+
+    async def _close(self, bint raise_on_error):
+        self._writer._close(raise_on_error)
+        data = self._buffer.collect()
+        if data:
+            await self._async_outfile.write(data)
+        if self._should_close:
+            await self._async_outfile.close()
+
+
+@cython.final
+@cython.internal
+cdef class _AsyncFileWriterElement:
+    cdef _FileWriterElement _element_writer
+    cdef _AsyncIncrementalFileWriter _writer
+
+    def __cinit__(self, _FileWriterElement element_writer not None,
+                  _AsyncIncrementalFileWriter writer not None):
+        self._element_writer = element_writer
+        self._writer = writer
+
+    async def __aenter__(self):
+        self._element_writer.__enter__()
+        data = self._writer._flush()
+        if data:
+            await self._writer._async_outfile.write(data)
+
+    async def __aexit__(self, *args):
+        self._element_writer.__exit__(*args)
+        data = self._writer._flush()
+        if data:
+            await self._writer._async_outfile.write(data)
+
+
+@cython.final
+@cython.internal
+@cython.freelist(8)
+cdef class _FileWriterElement:
+    cdef _IncrementalFileWriter _writer
+    cdef object _element
+    cdef int _new_method
+    cdef int _old_method
+
+    def __cinit__(self, _IncrementalFileWriter writer not None, element_config, int method):
+        self._writer = writer
+        self._element = element_config
+        self._new_method = method
+        self._old_method = writer._method
+
+    def __enter__(self):
+        self._writer._method = self._new_method
+        self._writer._write_start_element(self._element)
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        self._writer._write_end_element(self._element)
+        self._writer._method = self._old_method
+
+
+@cython.final
+@cython.internal
+@cython.freelist(8)
+cdef class _MethodChanger:
+    cdef _IncrementalFileWriter _writer
+    cdef int _new_method
+    cdef int _old_method
+    cdef bint _entered
+    cdef bint _exited
+
+    def __cinit__(self, _IncrementalFileWriter writer not None, int method):
+        self._writer = writer
+        self._new_method = method
+        self._old_method = writer._method
+        self._entered = False
+        self._exited = False
+
+    def __enter__(self):
+        if self._entered:
+            raise LxmlSyntaxError("Inconsistent enter action in context manager")
+        self._writer._method = self._new_method
+        self._entered = True
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        if self._exited:
+            raise LxmlSyntaxError("Inconsistent exit action in context manager")
+        if self._writer._method != self._new_method:
+            raise LxmlSyntaxError("Method changed outside of context manager")
+        self._writer._method = self._old_method
+        self._exited = True
+
+    async def __aenter__(self):
+        # for your async convenience
+        return self.__enter__()
+
+    async def __aexit__(self, *args):
+        # for your async convenience
+        return self.__exit__(*args)