// Evaluate an XPath. The returned result is stored in the struct. Call ReturnType to
// discover the type of result, and call one of the ResultAs* functions to return a
// copy of the result as a particular type.
func (xpath *XPath) Evaluate(nodePtr unsafe.Pointer, xpathExpr *Expression) (err error) {
if nodePtr == nil {
//evaluating xpath on a nil node returns no result.
return
}
oldXPContextDoc := xpath.ContextPtr.doc
oldXPContextNode := xpath.ContextPtr.node
oldXPProximityPosition := xpath.ContextPtr.proximityPosition
oldXPContextSize := xpath.ContextPtr.contextSize
oldXPNsNr := xpath.ContextPtr.nsNr
oldXPNamespaces := xpath.ContextPtr.namespaces
xpath.ContextPtr.node = (*C.xmlNode)(nodePtr)
if xpath.ResultPtr != nil {
C.xmlXPathFreeObject(xpath.ResultPtr)
}
xpath.ResultPtr = C.xmlXPathCompiledEval(xpathExpr.Ptr, xpath.ContextPtr)
xpath.ContextPtr.doc = oldXPContextDoc
xpath.ContextPtr.node = oldXPContextNode
xpath.ContextPtr.proximityPosition = oldXPProximityPosition
xpath.ContextPtr.contextSize = oldXPContextSize
xpath.ContextPtr.nsNr = oldXPNsNr
xpath.ContextPtr.namespaces = oldXPNamespaces
if xpath.ResultPtr == nil {
err = errors.New("err in evaluating xpath: " + xpathExpr.String())
return
}
return
}
//need to add an error as a return value b/c xpath evaluation can return error
func (xpath *XPath) Evaluate(nodePtr unsafe.Pointer, xpathExpr *Expression) (nodes []unsafe.Pointer, err error) {
if nodePtr == nil {
//evaluating xpath on a nil node returns no result.
return
}
xpath.ContextPtr.node = (*C.xmlNode)(nodePtr)
if xpath.ResultPtr != nil {
C.xmlXPathFreeObject(xpath.ResultPtr)
}
xpath.ResultPtr = C.xmlXPathCompiledEval(xpathExpr.Ptr, xpath.ContextPtr)
if xpath.ResultPtr == nil {
err = errors.New("err in evaluating xpath: " + xpathExpr.String())
return
}
if nodesetPtr := xpath.ResultPtr.nodesetval; nodesetPtr != nil {
if nodesetSize := int(nodesetPtr.nodeNr); nodesetSize > 0 {
nodes = make([]unsafe.Pointer, nodesetSize)
for i := 0; i < nodesetSize; i++ {
nodes[i] = unsafe.Pointer(C.fetchNode(nodesetPtr, C.int(i)))
}
}
}
return
}
func (x *XPathContext) evalXPath(expr *XPathExpression) (*XPathObject, error) {
if expr == nil {
return nil, errors.New("empty XPathExpression")
}
// If there is no document associated with this context,
// then xmlXPathCompiledEval() just fails to match
ctx := x.ptr
if ctx.node != nil && ctx.node.doc != nil {
ctx.doc = ctx.node.doc
}
if ctx.doc == nil {
ctx.doc = C.xmlNewDoc(stringToXmlChar("1.0"))
defer C.xmlFreeDoc(ctx.doc)
}
res := C.xmlXPathCompiledEval(expr.ptr, ctx)
if res == nil {
return nil, errors.New("empty result")
}
return &XPathObject{ptr: res}, nil
}
func (xpath *XPath) Evaluate(nodePtr unsafe.Pointer, xpathExpr *Expression) (nodes []unsafe.Pointer) {
if nodePtr == nil {
return
}
xpath.ContextPtr.node = (*C.xmlNode)(nodePtr)
if xpath.ResultPtr != nil {
C.xmlXPathFreeObject(xpath.ResultPtr)
}
xpath.ResultPtr = C.xmlXPathCompiledEval(xpathExpr.Ptr, xpath.ContextPtr)
if nodesetPtr := xpath.ResultPtr.nodesetval; nodesetPtr != nil {
if nodesetSize := int(nodesetPtr.nodeNr); nodesetSize > 0 {
nodes = make([]unsafe.Pointer, nodesetSize)
for i := 0; i < nodesetSize; i++ {
nodes[i] = unsafe.Pointer(C.fetchNode(nodesetPtr, C.int(i)))
}
}
}
return
}