Fix: libxml manual memory management

src/xml/attributes.cr

@@ -3,13 +3,13 @@ require "./node"
 class XML::Attributes
   include Enumerable(Node)
 
+  # :nodoc:
   def initialize(@node : Node)
   end
 
   def empty? : Bool
     return true unless @node.element?
 
-    props = self.props
     props.null?
   end
 
@@ -39,23 +39,54 @@ class XML::Attributes
   end
 
   def []=(name : String, value)
+    if prop = find_prop(name)
+      # manually unlink the prop's children if we have live references, so
+      # xmlSetProp won't free them immediately
+      @node.document.unlink_cached_children(prop)
+    end
+
     LibXML.xmlSetProp(@node, name, value.to_s)
     value
   end
 
   def delete(name : String) : String?
-    value = self[name]?.try &.content
-    res = LibXML.xmlUnsetProp(@node, name)
-    value if res == 0
+    prop = find_prop(name)
+    return unless prop
+
+    value = ""
+    if content = LibXML.xmlNodeGetContent(prop)
+      value = String.new(content)
+    end
+
+    if node = @node.document.cached?(prop)
+      # can't call xmlUnsetProp: it would free the node
+      node.unlink
+      value
+    else
+      # manually unlink the prop's children if we have live references, so
+      # xmlUnsetProp won't free them immediately
+      @node.document.unlink_cached_children(prop)
+      value if LibXML.xmlUnsetProp(@node, name) == 0
+    end
+  end
+
+  private def find_prop(name)
+    prop = @node.to_unsafe.value.properties.as(LibXML::Node*)
+    while prop
+      if String.new(prop.value.name) == name
+        return prop
+      end
+      prop = prop.value.next
+    end
   end
 
   def each(&) : Nil
     return unless @node.element?
 
     props = self.props
     until props.null?
-      yield Node.new(props)
-      props = props.value.next
+      yield Node.new(props.as(LibXML::Node*), @node.document)
+      props = props.value.next.as(LibXML::Attr*)
     end
   end
 
@@ -73,7 +104,7 @@ class XML::Attributes
     pp.list("[", self, "]")
   end
 
-  protected def props
+  protected def props : LibXML::Attr*
     @node.to_unsafe.value.properties
   end
 end

src/xml/builder.cr

@@ -28,6 +28,11 @@ class XML::Builder
     @writer = LibXML.xmlNewTextWriter(buffer)
   end
 
+  # :nodoc:
+  def finalize
+    LibXML.xmlFreeTextWriter(@writer)
+  end
+
   # Emits the start of the document.
   def start_document(version = nil, encoding = nil) : Nil
     call StartDocument, string_to_unsafe(version), string_to_unsafe(encoding), nil

src/xml/libxml2.cr

@@ -149,6 +149,7 @@ lib LibXML
   fun xmlTextReaderReadOuterXml(reader : XMLTextReader) : UInt8*
   fun xmlTextReaderExpand(reader : XMLTextReader) : Node*
   fun xmlTextReaderCurrentNode(reader : XMLTextReader) : Node*
+  fun xmlTextReaderCurrentDoc(reader : XMLTextReader) : Doc*
 
   fun xmlTextReaderSetErrorHandler(reader : XMLTextReader, f : TextReaderErrorFunc) : Void
   fun xmlTextReaderSetStructuredErrorHandler(reader : XMLTextReader, f : StructuredErrorFunc, arg : Void*) : Void
@@ -372,18 +373,14 @@ lib LibXML
   {% if compare_versions(LibXML::VERSION, "2.14.0") >= 0 %}
     fun xmlSaveSetIndentString(SaveCtxPtr, UInt8*)
   {% end %}
+
+  fun xmlFreeDoc(Doc*)
+  fun xmlFreeNode(Node*)
+  fun xmlFreeTextReader(XMLTextReader)
+  fun xmlFreeTextWriter(TextWriter)
+  fun xmlXPathFreeContext(XPathContext*)
+  fun xmlXPathFreeNodeSet(NodeSet*)
+  fun xmlXPathFreeObject(XPathObject*)
 end
 
 LibXML.xmlInitParser
-
-LibXML.xmlMemSetup(
-  ->GC.free,
-  ->GC.malloc(LibC::SizeT),
-  ->GC.realloc(Void*, LibC::SizeT),
-  ->(str) {
-    len = LibC.strlen(str) + 1
-    copy = Pointer(UInt8).malloc(len)
-    copy.copy_from(str, len)
-    copy
-  }
-)

src/xml/namespace.cr

@@ -1,6 +1,7 @@
 class XML::Namespace
   getter document : Node
 
+  # :nodoc:
   def initialize(@document : Node, @ns : LibXML::NS*)
   end