Ok, great. I'm not used to explicit mem management from Julia so appreciate
feedback on proposed solution:
function free(xelem::XMLElement)
ccall(xmlFreeNode, Void, (Ptr{Void},), xelem.node.ptr)
xelem.node.ptr = nullptr
end
since XMLElement type has a node::XMLNode attribute and the XMLNode type
has a ptr::Xptr and free for XMLDocument uses xmlFreeDoc like so:
function free(xdoc::XMLDocument)
ccall(xmlFreeDoc, Void, (Ptr{Void},), xdoc.ptr)
xdoc.ptr = nullptr
end
and then add free as finalizer in constructor for XMLElement like so:
function XMLElement(node::XMLNode)
if !is_elementnode(node)
throw(ArgumentError("The input node is not an element."))
end
xelem = new(node)
finalize(xelem, free)
xelem
end
I will try this and see if it addresses my problems but would be great with
input on this.
Cheers,
Robert
Den måndag 26 januari 2015 kl. 15:49:14 UTC+1 skrev Isaiah:
>
> The underlying XMLNode needs to be freed using xmlFreeNode from libxml2:
>
> http://xmlsoft.org/html/libxml-tree.html#xmlFreeNode
>
> I don't think this is wrapped yet, but it should be straightforward to add
> -- ideally, called via a finalizer so that the objects are freed
> automatically when Julia decides they can be GC'd.
>
> On Mon, Jan 26, 2015 at 7:42 AM, Robert Feldt <robert...@gmail.com
> <javascript:>> wrote:
>
>> Hi,
>>
>> Does anyone now how to free up the memory in a XMLElement object in
>> LightXML.jl?
>>
>> LightXML.jl has a free(xdoc::XMLDocument) but no corresponding
>> free(xelem::XMLElement). There are functions related to free in clib.jl in
>> the package but no docs that I can find on how to use it. I tried to create
>> an XMLDocument from the element and then free the document but mem still
>> leaks. Help appreciated.
>>
>> Background/context/details:
>>
>> In another thread we found out that our problems with mem-leaks in a
>> long-running optimization is probably due to the use of LightXML.jl. The
>> latter seem to require manual free'ing of resources as of the current
>> version. Basically our main loop is something like this:
>>
>> # Create a large number of XMLElement's (possibly deeply nested) with
>> construct_element(name::String, content::Array{Any}) = begin
>> xmlelement = new_element(name)
>> for item in content
>> if typeof(item) <: Main.XMLElement
>> add_child(xmlelement, item)
>> elseif typeof(item) <: (String,String)
>> set_attribute(xmlelement, item[1], item[2])
>> elseif typeof(item) <: String
>> add_text(xmlelement, item)
>> else
>> @assert false
>> end
>> end
>> xmlelement
>> end
>>
>> # What we are optimizing is the length of the xml when printed as string
>> so we evaluated this by looping over array of xml elements generated
>> # by construct_element above and calling on each one (the replace is for
>> taking away at least some of the whitespace which is not important):
>> fitness(xml) = length(replace(string(xml), r">\s+<", "><"))
>>
>> Since the optimization algorithm calls fitness on 100K to several million
>> xml elements per run when we compare several optimization algorithms to
>> each other the mem expansion gets up to many gigs and eventually there is
>> problems. It seems there is no free on XMLElement in LightXML.jl but there
>> is a free for XMLDocument. We thus tried to change to this:
>>
>> free_xmlelement(xmlelem::XMLElement) = begin
>> tempdoc = XMLDocument()
>> set_root(tempdoc, xmlelem)
>> free(tempdoc)
>> end
>> fitness_with_free(xml) = begin
>> qv = length(replace(string(xml), r">\s+<", "><"))
>> free_xmlelement(xml)
>> qv
>> end
>>
>> but it does not seem to help. We would appreciate any help/advice on this
>> or how we can further debug it. The documentation for xmlFreeDoc in
>> libxml2 (which is what is what LightXML.free(xdoc::XMLDocument) calls)
>> says that it will recursively free the document. But maybe we are missing
>> something.
>>
>> Thanks for any advice,
>>
>> Robert Feldt
>>
>
>
