//export exec_xpath_function
func exec_xpath_function(ctxt C.xmlXPathParserContextPtr, nargs C.int) {
function := C.GoString((*C.char)(unsafe.Pointer(ctxt.context.function)))
namespace := C.GoString((*C.char)(unsafe.Pointer(ctxt.context.functionURI)))
context := (*VariableScope)(ctxt.context.funcLookupData)
argcount := int(nargs)
var args []interface{}
for i := 0; i < argcount; i = i + 1 {
args = append(args, XPathObjectToValue(C.valuePop(ctxt)))
}
// arguments are popped off the stack in reverse order, so
// we reverse the slice before invoking our callback
if argcount > 1 {
for i, j := 0, len(args)-1; i < j; i, j = i+1, j-1 {
args[i], args[j] = args[j], args[i]
}
}
// push the result onto the stack
// if for some reason we are unable to resolve the
// function we push an empty nodeset
f := (*context).ResolveFunction(function, namespace)
if f != nil {
retval := f(*context, args)
C.valuePush(ctxt, ValueToXPathObject(retval))
} else {
ret := C.xmlXPathNewNodeSet(nil)
C.valuePush(ctxt, ret)
}
}
// Produce a C.xmlXPathObjectPtr suitable for passing to libxml2
func (n Nodeset) ToXPathNodeset() (ret C.xmlXPathObjectPtr) {
ret = C.xmlXPathNewNodeSet(nil)
for _, node := range n {
C.xmlXPathNodeSetAdd(ret.nodesetval, (*C.xmlNode)(node.NodePtr()))
}
return
}
// Convert an arbitrary value into a C.xmlXPathObjectPtr
// Unrecognised and nil values are converted to empty node sets.
func ValueToXPathObject(val interface{}) (ret C.xmlXPathObjectPtr) {
if val == nil {
//return the empty node set
ret = C.xmlXPathNewNodeSet(nil)
return
}
switch v := val.(type) {
case unsafe.Pointer:
return (C.xmlXPathObjectPtr)(v)
case []unsafe.Pointer:
ptrs := v
if len(ptrs) > 0 {
//default - return a node set
ret = C.xmlXPathNewNodeSet(nil)
for _, p := range ptrs {
C.xmlXPathNodeSetAdd(ret.nodesetval, (*C.xmlNode)(p))
}
} else {
ret = C.xmlXPathNewNodeSet(nil)
return
}
case float64:
ret = C.xmlXPathNewFloat(C.double(v))
case string:
xpathBytes := GetCString([]byte(v))
xpathPtr := unsafe.Pointer(&xpathBytes[0])
ret = C.xmlXPathNewString((*C.xmlChar)(xpathPtr))
default:
typ := reflect.TypeOf(val)
// if a pointer to a struct is passed, get the type of the dereferenced object
if typ.Kind() == reflect.Ptr {
typ = typ.Elem()
}
//log the unknown type, return an empty node set
//fmt.Println("go-resolve wrong-type", typ.Kind())
ret = C.xmlXPathNewNodeSet(nil)
}
return
}