[gxml] Added XPathContext and XPathObject interfaces

[Daniel Espinosa Ortiz <despinosa src gnome org>]

commit 66270bf75332b5ba052cfc9859148d42981e63fa
Author: Daniel Espinosa <esodan gmail com>
Date:   Thu Sep 29 12:39:29 2016 -0500

    Added XPathContext and XPathObject interfaces
    
    * Fixes bug #772195
    * Now GElement implements XPathContext
    * Added new class GXPathObject implementing XPathObject
    * Moved new method for XPath in DomElement to XPathContext

 gxml/DomElement.vala  |    9 ---------
 gxml/GXmlElement.vala |   18 ++++++++++++------
 gxml/Makefile.am      |    1 +
 3 files changed, 13 insertions(+), 15 deletions(-)
---
diff --git a/gxml/DomElement.vala b/gxml/DomElement.vala
index bae3d8d..f28da7b 100644
--- a/gxml/DomElement.vala
+++ b/gxml/DomElement.vala
@@ -56,15 +56,6 @@ public interface GXml.DomElement : GLib.Object,
   public abstract DomHTMLCollection get_elements_by_tag_name(string local_name);
   public abstract DomHTMLCollection get_elements_by_tag_name_ns (string? namespace, string local_name);
   public abstract DomHTMLCollection get_elements_by_class_name (string class_names);
-
-  /**
-   * Evaluate XPath expression.
-   * 
-   * This method evaluates provided expression, registers provided namespaces in resolver and returns an 
{@link GXml.XPath.Object}.
-   * 
-   * Throw {@link GXml.XPath.Error} if one of provided namespaces is invalid.
-   */
-  public abstract GXml.XPath.Object evaluate (string expression, Gee.List<GXml.Namespace>? resolver = null) 
throws GXml.XPath.Error;
 }
 
 public class GXml.DomElementList : Gee.ArrayList<DomElement>, GXml.DomHTMLCollection {
diff --git a/gxml/GXmlElement.vala b/gxml/GXmlElement.vala
index 1a2211c..11c0c26 100644
--- a/gxml/GXmlElement.vala
+++ b/gxml/GXmlElement.vala
@@ -2,6 +2,7 @@
 /* GElement.vala
  *
  * Copyright (C) 2016  Daniel Espinosa <esodan gmail com>
+ * Copyright (C) 2016  Yannick Inizan <inizan yannick gmail com>
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -27,7 +28,9 @@ using Gee;
  */
 public class GXml.GElement : GXml.GNonDocumentChildNode,
                             GXml.DomParentNode,
-                            GXml.DomElement, GXml.Element
+                            GXml.DomElement,
+                            GXml.Element,
+                            GXml.XPathContext
 {
   public GElement (GDocument doc, Xml.Node *node) {
     _node = node;
@@ -316,11 +319,14 @@ public class GXml.GElement : GXml.GNonDocumentChildNode,
   // FIXME:
     throw new DomError.SYNTAX_ERROR (_("DomElement query_selector_all is not implemented"));
   }
-  
+  // XPathContext implementation
   /**
-   * {@inheritDoc} 
+   * {@inheritDoc}
    */
-  public GXml.XPath.Object evaluate (string expression, Gee.List<GXml.Namespace>? resolver = null) throws 
GXml.XPath.Error {
+  public GXml.XPathObject evaluate (string expression,
+                                    Gee.List<GXml.Namespace>? resolver = null)
+                                    throws GXml.XPathError
+  {
     if (!(this is GXml.Node))
       return null;
     string data = (this as GXml.Node).to_string();
@@ -331,12 +337,12 @@ public class GXml.GElement : GXml.GNonDocumentChildNode,
          resolver.foreach (ns => {
                int res = context.register_ns (ns.prefix, ns.uri);
                if (res != 0) {
-                 var err = new GXml.XPath.Error.EXPRESSION_OK ("invalid namespace.");
+                 var err = new GXml.XPathError.EXPRESSION_OK ("invalid namespace.");
                  err.code = res;
                  throw err;
         }
         return true; 
       });
-    return new GXml.XPath.Object (gdoc, context.eval (expression));
+    return new GXml.GXPathObject (gdoc, context.eval (expression));
   }
 }
diff --git a/gxml/Makefile.am b/gxml/Makefile.am
index f708ccf..06863af 100644
--- a/gxml/Makefile.am
+++ b/gxml/Makefile.am
@@ -110,6 +110,7 @@ sources = \
        DomNode.vala \
        DomRange.vala \
        XPath.vala \
+       GXPathObject.vala \
        $(NULL)