Mini Shell
# Proxy functions and low level node allocation stuff
# Proxies represent elements, their reference is stored in the C
# structure of the respective node to avoid multiple instantiation of
# the Python class.
@cython.linetrace(False)
@cython.profile(False)
cdef inline _Element getProxy(xmlNode* c_node):
u"""Get a proxy for a given node.
"""
#print "getProxy for:", <int>c_node
if c_node is not NULL and c_node._private is not NULL:
return <_Element>c_node._private
else:
return None
@cython.linetrace(False)
@cython.profile(False)
cdef inline bint hasProxy(xmlNode* c_node):
if c_node._private is NULL:
return False
return True
@cython.linetrace(False)
@cython.profile(False)
cdef inline int _registerProxy(_Element proxy, _Document doc,
xmlNode* c_node) except -1:
u"""Register a proxy and type for the node it's proxying for.
"""
#print "registering for:", <int>proxy._c_node
assert not hasProxy(c_node), u"double registering proxy!"
proxy._doc = doc
proxy._c_node = c_node
c_node._private = <void*>proxy
return 0
@cython.linetrace(False)
@cython.profile(False)
cdef inline int _unregisterProxy(_Element proxy) except -1:
u"""Unregister a proxy for the node it's proxying for.
"""
cdef xmlNode* c_node = proxy._c_node
assert c_node._private is <void*>proxy, u"Tried to unregister unknown proxy"
c_node._private = NULL
return 0
################################################################################
# temporarily make a node the root node of its document
cdef xmlDoc* _fakeRootDoc(xmlDoc* c_base_doc, xmlNode* c_node) except NULL:
return _plainFakeRootDoc(c_base_doc, c_node, 1)
cdef xmlDoc* _plainFakeRootDoc(xmlDoc* c_base_doc, xmlNode* c_node,
bint with_siblings) except NULL:
# build a temporary document that has the given node as root node
# note that copy and original must not be modified during its lifetime!!
# always call _destroyFakeDoc() after use!
cdef xmlNode* c_child
cdef xmlNode* c_root
cdef xmlNode* c_new_root
cdef xmlDoc* c_doc
if with_siblings or (c_node.prev is NULL and c_node.next is NULL):
c_root = tree.xmlDocGetRootElement(c_base_doc)
if c_root is c_node:
# already the root node, no siblings
return c_base_doc
c_doc = _copyDoc(c_base_doc, 0) # non recursive!
c_new_root = tree.xmlDocCopyNode(c_node, c_doc, 2) # non recursive!
tree.xmlDocSetRootElement(c_doc, c_new_root)
_copyParentNamespaces(c_node, c_new_root)
c_new_root.children = c_node.children
c_new_root.last = c_node.last
c_new_root.next = c_new_root.prev = NULL
# store original node
c_doc._private = c_node
# divert parent pointers of children
c_child = c_new_root.children
while c_child is not NULL:
c_child.parent = c_new_root
c_child = c_child.next
c_doc.children = c_new_root
return c_doc
cdef void _destroyFakeDoc(xmlDoc* c_base_doc, xmlDoc* c_doc):
# delete a temporary document
cdef xmlNode* c_child
cdef xmlNode* c_parent
cdef xmlNode* c_root
if c_doc is c_base_doc:
return
c_root = tree.xmlDocGetRootElement(c_doc)
# restore parent pointers of children
c_parent = <xmlNode*>c_doc._private
c_child = c_root.children
while c_child is not NULL:
c_child.parent = c_parent
c_child = c_child.next
# prevent recursive removal of children
c_root.children = c_root.last = NULL
tree.xmlFreeDoc(c_doc)
cdef _Element _fakeDocElementFactory(_Document doc, xmlNode* c_element):
u"""Special element factory for cases where we need to create a fake
root document, but still need to instantiate arbitrary nodes from
it. If we instantiate the fake root node, things will turn bad
when it's destroyed.
Instead, if we are asked to instantiate the fake root node, we
instantiate the original node instead.
"""
if c_element.doc is not doc._c_doc:
if c_element.doc._private is not NULL:
if c_element is c_element.doc.children:
c_element = <xmlNode*>c_element.doc._private
#assert c_element.type == tree.XML_ELEMENT_NODE
return _elementFactory(doc, c_element)
################################################################################
# support for freeing tree elements when proxy objects are destroyed
cdef int attemptDeallocation(xmlNode* c_node):
u"""Attempt deallocation of c_node (or higher up in tree).
"""
cdef xmlNode* c_top
# could be we actually aren't referring to the tree at all
if c_node is NULL:
#print "not freeing, node is NULL"
return 0
c_top = getDeallocationTop(c_node)
if c_top is not NULL:
#print "freeing:", c_top.name
_removeText(c_top.next) # tail
tree.xmlFreeNode(c_top)
return 1
return 0
cdef xmlNode* getDeallocationTop(xmlNode* c_node):
u"""Return the top of the tree that can be deallocated, or NULL.
"""
cdef xmlNode* c_next
#print "trying to do deallocating:", c_node.type
if hasProxy(c_node):
#print "Not freeing: proxies still exist"
return NULL
while c_node.parent is not NULL:
c_node = c_node.parent
#print "checking:", c_current.type
if c_node.type == tree.XML_DOCUMENT_NODE or \
c_node.type == tree.XML_HTML_DOCUMENT_NODE:
#print "not freeing: still in doc"
return NULL
# if we're still attached to the document, don't deallocate
if hasProxy(c_node):
#print "Not freeing: proxies still exist"
return NULL
# see whether we have children to deallocate
if not canDeallocateChildNodes(c_node):
return NULL
# see whether we have siblings to deallocate
c_next = c_node.prev
while c_next:
if _isElement(c_next):
if hasProxy(c_next) or not canDeallocateChildNodes(c_next):
return NULL
c_next = c_next.prev
c_next = c_node.next
while c_next:
if _isElement(c_next):
if hasProxy(c_next) or not canDeallocateChildNodes(c_next):
return NULL
c_next = c_next.next
return c_node
cdef int canDeallocateChildNodes(xmlNode* c_parent):
cdef xmlNode* c_node
c_node = c_parent.children
tree.BEGIN_FOR_EACH_ELEMENT_FROM(c_parent, c_node, 1)
if hasProxy(c_node):
return 0
tree.END_FOR_EACH_ELEMENT_FROM(c_node)
return 1
################################################################################
# fix _Document references and namespaces when a node changes documents
cdef void _copyParentNamespaces(xmlNode* c_from_node, xmlNode* c_to_node) nogil:
u"""Copy the namespaces of all ancestors of c_from_node to c_to_node.
"""
cdef xmlNode* c_parent
cdef xmlNs* c_ns
cdef xmlNs* c_new_ns
cdef int prefix_known
c_parent = c_from_node.parent
while c_parent and (tree._isElementOrXInclude(c_parent) or
c_parent.type == tree.XML_DOCUMENT_NODE):
c_new_ns = c_parent.nsDef
while c_new_ns:
# libxml2 will check if the prefix is already defined
tree.xmlNewNs(c_to_node, c_new_ns.href, c_new_ns.prefix)
c_new_ns = c_new_ns.next
c_parent = c_parent.parent
ctypedef struct _ns_update_map:
xmlNs* old
xmlNs* new
ctypedef struct _nscache:
_ns_update_map* ns_map
size_t size
size_t last
cdef int _growNsCache(_nscache* c_ns_cache) except -1:
cdef _ns_update_map* ns_map_ptr
if c_ns_cache.size == 0:
c_ns_cache.size = 20
else:
c_ns_cache.size *= 2
ns_map_ptr = <_ns_update_map*> python.lxml_realloc(
c_ns_cache.ns_map, c_ns_cache.size, sizeof(_ns_update_map))
if not ns_map_ptr:
python.lxml_free(c_ns_cache.ns_map)
c_ns_cache.ns_map = NULL
raise MemoryError()
c_ns_cache.ns_map = ns_map_ptr
return 0
cdef inline int _appendToNsCache(_nscache* c_ns_cache,
xmlNs* c_old_ns, xmlNs* c_new_ns) except -1:
if c_ns_cache.last >= c_ns_cache.size:
_growNsCache(c_ns_cache)
c_ns_cache.ns_map[c_ns_cache.last] = _ns_update_map(old=c_old_ns, new=c_new_ns)
c_ns_cache.last += 1
cdef int _stripRedundantNamespaceDeclarations(xmlNode* c_element, _nscache* c_ns_cache,
xmlNs** c_del_ns_list) except -1:
u"""Removes namespace declarations from an element that are already
defined in its parents. Does not free the xmlNs's, just prepends
them to the c_del_ns_list.
"""
cdef xmlNs* c_ns
cdef xmlNs* c_ns_next
cdef xmlNs** c_nsdef
# use a xmlNs** to handle assignments to "c_element.nsDef" correctly
c_nsdef = &c_element.nsDef
while c_nsdef[0] is not NULL:
c_ns = tree.xmlSearchNsByHref(
c_element.doc, c_element.parent, c_nsdef[0].href)
if c_ns is NULL:
# new namespace href => keep and cache the ns declaration
_appendToNsCache(c_ns_cache, c_nsdef[0], c_nsdef[0])
c_nsdef = &c_nsdef[0].next
else:
# known namespace href => cache mapping and strip old ns
_appendToNsCache(c_ns_cache, c_nsdef[0], c_ns)
# cut out c_nsdef.next and prepend it to garbage chain
c_ns_next = c_nsdef[0].next
c_nsdef[0].next = c_del_ns_list[0]
c_del_ns_list[0] = c_nsdef[0]
c_nsdef[0] = c_ns_next
return 0
cdef void _cleanUpFromNamespaceAdaptation(xmlNode* c_start_node,
_nscache* c_ns_cache, xmlNs* c_del_ns_list):
# Try to recover from exceptions with really bad timing. We were in the middle
# of ripping out xmlNS-es and likely ran out of memory. Try to fix up the tree
# by re-adding the original xmlNs declarations (which might still be used in some
# places).
if c_ns_cache.ns_map:
python.lxml_free(c_ns_cache.ns_map)
if c_del_ns_list:
if not c_start_node.nsDef:
c_start_node.nsDef = c_del_ns_list
else:
c_ns = c_start_node.nsDef
while c_ns.next:
c_ns = c_ns.next
c_ns.next = c_del_ns_list
cdef int moveNodeToDocument(_Document doc, xmlDoc* c_source_doc,
xmlNode* c_element) except -1:
u"""Fix the xmlNs pointers of a node and its subtree that were moved.
Originally copied from libxml2's xmlReconciliateNs(). Expects
libxml2 doc pointers of node to be correct already, but fixes
_Document references.
For each node in the subtree, we do this:
1) Remove redundant declarations of namespace that are already
defined in its parents.
2) Replace namespaces that are *not* defined on the node or its
parents by the equivalent namespace declarations that *are*
defined on the node or its parents (possibly using a different
prefix). If a namespace is unknown, declare a new one on the
node.
3) Reassign the names of tags and attribute from the dict of the
target document *iff* it is different from the dict used in the
source subtree.
4) Set the Document reference to the new Document (if different).
This is done on backtracking to keep the original Document
alive as long as possible, until all its elements are updated.
Note that the namespace declarations are removed from the tree in
step 1), but freed only after the complete subtree was traversed
and all occurrences were replaced by tree-internal pointers.
"""
cdef xmlNode* c_start_node
cdef xmlNode* c_node
cdef xmlDoc* c_doc = doc._c_doc
cdef tree.xmlAttr* c_attr
cdef char* c_name
cdef _nscache c_ns_cache = [NULL, 0, 0]
cdef xmlNs* c_del_ns_list = NULL
cdef proxy_count = 0
if not tree._isElementOrXInclude(c_element):
return 0
c_start_node = c_element
tree.BEGIN_FOR_EACH_FROM(c_element, c_element, 1)
if tree._isElementOrXInclude(c_element):
if hasProxy(c_element):
proxy_count += 1
# 1) cut out namespaces defined here that are already known by
# the ancestors
if c_element.nsDef is not NULL:
try:
_stripRedundantNamespaceDeclarations(c_element, &c_ns_cache, &c_del_ns_list)
except:
_cleanUpFromNamespaceAdaptation(c_start_node, &c_ns_cache, c_del_ns_list)
raise
# 2) make sure the namespaces of an element and its attributes
# are declared in this document (i.e. on the node or its parents)
if c_element.ns is not NULL:
_fixCNs(doc, c_start_node, c_element, &c_ns_cache, c_del_ns_list)
c_node = <xmlNode*>c_element.properties
while c_node is not NULL:
if c_node.ns is not NULL:
_fixCNs(doc, c_start_node, c_node, &c_ns_cache, c_del_ns_list)
c_node = c_node.next
tree.END_FOR_EACH_FROM(c_element)
# free now unused namespace declarations
if c_del_ns_list is not NULL:
tree.xmlFreeNsList(c_del_ns_list)
# cleanup
if c_ns_cache.ns_map is not NULL:
python.lxml_free(c_ns_cache.ns_map)
# 3) fix the names in the tree if we moved it from a different thread
if doc._c_doc.dict is not c_source_doc.dict:
fixThreadDictNames(c_start_node, c_source_doc.dict, doc._c_doc.dict)
# 4) fix _Document references
# (and potentially deallocate the source document)
if proxy_count > 0:
if proxy_count == 1 and c_start_node._private is not NULL:
proxy = getProxy(c_start_node)
if proxy is not None:
if proxy._doc is not doc:
proxy._doc = doc
else:
fixElementDocument(c_start_node, doc, proxy_count)
else:
fixElementDocument(c_start_node, doc, proxy_count)
return 0
cdef void _setTreeDoc(xmlNode* c_node, xmlDoc* c_doc):
"""Adaptation of 'xmlSetTreeDoc()' that deep-fixes the document links iteratively.
It avoids https://gitlab.gnome.org/GNOME/libxml2/issues/42
"""
tree.BEGIN_FOR_EACH_FROM(c_node, c_node, 1)
if c_node.type == tree.XML_ELEMENT_NODE:
c_attr = <tree.xmlAttr*>c_node.properties
while c_attr:
if c_attr.atype == tree.XML_ATTRIBUTE_ID:
tree.xmlRemoveID(c_node.doc, c_attr)
c_attr.doc = c_doc
_fixDocChildren(c_attr.children, c_doc)
c_attr = c_attr.next
# Set doc link for all nodes, not only elements.
c_node.doc = c_doc
tree.END_FOR_EACH_FROM(c_node)
cdef inline void _fixDocChildren(xmlNode* c_child, xmlDoc* c_doc):
while c_child:
c_child.doc = c_doc
if c_child.children:
_fixDocChildren(c_child.children, c_doc)
c_child = c_child.next
cdef int _fixCNs(_Document doc, xmlNode* c_start_node, xmlNode* c_node,
_nscache* c_ns_cache, xmlNs* c_del_ns_list) except -1:
cdef xmlNs* c_ns = NULL
cdef bint is_prefixed_attr = (c_node.type == tree.XML_ATTRIBUTE_NODE and c_node.ns.prefix)
for ns_map in c_ns_cache.ns_map[:c_ns_cache.last]:
if c_node.ns is ns_map.old:
if is_prefixed_attr and not ns_map.new.prefix:
# avoid dropping prefix from attributes
continue
c_ns = ns_map.new
break
if c_ns:
c_node.ns = c_ns
else:
# not in cache or not acceptable
# => find a replacement from this document
try:
c_ns = doc._findOrBuildNodeNs(
c_start_node, c_node.ns.href, c_node.ns.prefix,
c_node.type == tree.XML_ATTRIBUTE_NODE)
c_node.ns = c_ns
_appendToNsCache(c_ns_cache, c_node.ns, c_ns)
except:
_cleanUpFromNamespaceAdaptation(c_start_node, c_ns_cache, c_del_ns_list)
raise
return 0
cdef void fixElementDocument(xmlNode* c_element, _Document doc,
size_t proxy_count):
cdef xmlNode* c_node = c_element
cdef _Element proxy = None # init-to-None required due to fake-loop below
tree.BEGIN_FOR_EACH_FROM(c_element, c_node, 1)
if c_node._private is not NULL:
proxy = getProxy(c_node)
if proxy is not None:
if proxy._doc is not doc:
proxy._doc = doc
proxy_count -= 1
if proxy_count == 0:
return
tree.END_FOR_EACH_FROM(c_node)
cdef void fixThreadDictNames(xmlNode* c_element,
tree.xmlDict* c_src_dict,
tree.xmlDict* c_dict) nogil:
# re-assign the names of tags and attributes
#
# this should only be called when the element is based on a
# different libxml2 tag name dictionary
if c_element.type == tree.XML_DOCUMENT_NODE or \
c_element.type == tree.XML_HTML_DOCUMENT_NODE:
# may define "xml" namespace
fixThreadDictNsForNode(c_element, c_src_dict, c_dict)
if c_element.doc.extSubset:
fixThreadDictNamesForDtd(c_element.doc.extSubset, c_src_dict, c_dict)
if c_element.doc.intSubset:
fixThreadDictNamesForDtd(c_element.doc.intSubset, c_src_dict, c_dict)
c_element = c_element.children
while c_element is not NULL:
fixThreadDictNamesForNode(c_element, c_src_dict, c_dict)
c_element = c_element.next
elif tree._isElementOrXInclude(c_element):
fixThreadDictNamesForNode(c_element, c_src_dict, c_dict)
cdef inline void _fixThreadDictPtr(const_xmlChar** c_ptr,
tree.xmlDict* c_src_dict,
tree.xmlDict* c_dict) nogil:
c_str = c_ptr[0]
if c_str and c_src_dict and tree.xmlDictOwns(c_src_dict, c_str):
# return value can be NULL on memory error, but we don't handle that here
c_str = tree.xmlDictLookup(c_dict, c_str, -1)
if c_str:
c_ptr[0] = c_str
cdef void fixThreadDictNamesForNode(xmlNode* c_element,
tree.xmlDict* c_src_dict,
tree.xmlDict* c_dict) nogil:
cdef xmlNode* c_node = c_element
tree.BEGIN_FOR_EACH_FROM(c_element, c_node, 1)
if c_node.type in (tree.XML_ELEMENT_NODE, tree.XML_XINCLUDE_START):
fixThreadDictNamesForAttributes(
c_node.properties, c_src_dict, c_dict)
fixThreadDictNsForNode(c_node, c_src_dict, c_dict)
_fixThreadDictPtr(&c_node.name, c_src_dict, c_dict)
elif c_node.type == tree.XML_TEXT_NODE:
# libxml2's SAX2 parser interns some indentation space
fixThreadDictContentForNode(c_node, c_src_dict, c_dict)
elif c_node.type == tree.XML_COMMENT_NODE:
pass # don't touch c_node.name
else:
_fixThreadDictPtr(&c_node.name, c_src_dict, c_dict)
tree.END_FOR_EACH_FROM(c_node)
cdef inline void fixThreadDictNamesForAttributes(tree.xmlAttr* c_attr,
tree.xmlDict* c_src_dict,
tree.xmlDict* c_dict) nogil:
cdef xmlNode* c_child
cdef xmlNode* c_node = <xmlNode*>c_attr
while c_node is not NULL:
if c_node.type not in (tree.XML_TEXT_NODE, tree.XML_COMMENT_NODE):
_fixThreadDictPtr(&c_node.name, c_src_dict, c_dict)
# libxml2 keeps some (!) attribute values in the dict
c_child = c_node.children
while c_child is not NULL:
fixThreadDictContentForNode(c_child, c_src_dict, c_dict)
c_child = c_child.next
c_node = c_node.next
cdef inline void fixThreadDictContentForNode(xmlNode* c_node,
tree.xmlDict* c_src_dict,
tree.xmlDict* c_dict) nogil:
if c_node.content is not NULL and \
c_node.content is not <xmlChar*>&c_node.properties:
if tree.xmlDictOwns(c_src_dict, c_node.content):
# result can be NULL on memory error, but we don't handle that here
c_node.content = <xmlChar*>tree.xmlDictLookup(c_dict, c_node.content, -1)
cdef inline void fixThreadDictNsForNode(xmlNode* c_node,
tree.xmlDict* c_src_dict,
tree.xmlDict* c_dict) nogil:
cdef xmlNs* c_ns = c_node.nsDef
while c_ns is not NULL:
_fixThreadDictPtr(&c_ns.href, c_src_dict, c_dict)
_fixThreadDictPtr(&c_ns.prefix, c_src_dict, c_dict)
c_ns = c_ns.next
cdef void fixThreadDictNamesForDtd(tree.xmlDtd* c_dtd,
tree.xmlDict* c_src_dict,
tree.xmlDict* c_dict) nogil:
cdef xmlNode* c_node
cdef tree.xmlElement* c_element
cdef tree.xmlAttribute* c_attribute
cdef tree.xmlEntity* c_entity
c_node = c_dtd.children
while c_node:
if c_node.type == tree.XML_ELEMENT_DECL:
c_element = <tree.xmlElement*>c_node
if c_element.content:
_fixThreadDictPtr(&c_element.content.name, c_src_dict, c_dict)
_fixThreadDictPtr(&c_element.content.prefix, c_src_dict, c_dict)
c_attribute = c_element.attributes
while c_attribute:
_fixThreadDictPtr(&c_attribute.defaultValue, c_src_dict, c_dict)
_fixThreadDictPtr(&c_attribute.name, c_src_dict, c_dict)
_fixThreadDictPtr(&c_attribute.prefix, c_src_dict, c_dict)
_fixThreadDictPtr(&c_attribute.elem, c_src_dict, c_dict)
c_attribute = c_attribute.nexth
elif c_node.type == tree.XML_ENTITY_DECL:
c_entity = <tree.xmlEntity*>c_node
_fixThreadDictPtr(&c_entity.name, c_src_dict, c_dict)
_fixThreadDictPtr(&c_entity.ExternalID, c_src_dict, c_dict)
_fixThreadDictPtr(&c_entity.SystemID, c_src_dict, c_dict)
_fixThreadDictPtr(<const_xmlChar**>&c_entity.content, c_src_dict, c_dict)
c_node = c_node.next
################################################################################
# adopt an xmlDoc from an external libxml2 document source
cdef _Document _adoptForeignDoc(xmlDoc* c_doc, _BaseParser parser=None, bint is_owned=True):
"""Convert and wrap an externally produced xmlDoc for use in lxml.
Assures that all '_private' pointers are NULL to prevent accidental
dereference into lxml proxy objects.
"""
if c_doc is NULL:
raise ValueError("Illegal document provided: NULL")
if c_doc.type not in (tree.XML_DOCUMENT_NODE, tree.XML_HTML_DOCUMENT_NODE):
doc_type = c_doc.type
if is_owned:
tree.xmlFreeDoc(c_doc)
raise ValueError(f"Illegal document provided: expected XML or HTML, found {doc_type}")
cdef xmlNode* c_node = <xmlNode*>c_doc
if is_owned:
tree.BEGIN_FOR_EACH_FROM(<xmlNode*>c_doc, c_node, 1)
c_node._private = NULL
tree.END_FOR_EACH_FROM(c_node)
else:
# create a fresh copy that lxml owns
c_doc = tree.xmlCopyDoc(c_doc, 1)
if c_doc is NULL:
raise MemoryError()
return _documentFactory(c_doc, parser)
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