[gxml] New GomCollection interface and GomArrayList class

[Daniel Espinosa Ortiz <despinosa src gnome org>]

commit bde10660cceeb7c24d9264068869ab2838d180bd
Author: Daniel Espinosa <esodan gmail com>
Date:   Sat Nov 5 23:24:15 2016 -0600

    New GomCollection interface and GomArrayList class
    
    GomCollection is an interface to store references
    to XML Elements as child of a given parent element.
    GomArrayList implement GomCollection to support
    ordered and indexed references to elements.

 gxml/GomCollections.vala |   97 ++++++++++++++++++++++++++++++++++++++++++++++
 gxml/Makefile.am         |    1 +
 2 files changed, 98 insertions(+), 0 deletions(-)
---
diff --git a/gxml/GomCollections.vala b/gxml/GomCollections.vala
new file mode 100644
index 0000000..19677f9
--- /dev/null
+++ b/gxml/GomCollections.vala
@@ -0,0 +1,97 @@
+/* -*- Mode: vala; indent-tabs-mode: nil; c-basic-offset: 2; tab-width: 2 -*- */
+/*
+ *
+ * Copyright (C) 2016  Daniel Espinosa <esodan gmail com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors:
+ *      Daniel Espinosa <esodan gmail com>
+ */
+
+
+/**
+ * An interface to keep references to {@link DomElement} in a {@link element}
+ * child nodes. Only {@link GomObject} are supported. It can be filled out
+ * using {@link update}.
+ */
+public interface GXml.GomCollection : Object
+{
+  /**
+   * A list of child {@link DomElement} objects of {@link element}
+   */
+  public abstract List<int> nodes_index { get; }
+  /**
+   * A {@link DomElement} with all child elements.
+   */
+  public abstract DomElement element { get; construct set; }
+  /**
+   * Local name of {@link DomElement} objects of {@link element}, which could be
+   * contained in this collection.
+   */
+  public abstract string element_name { get; construct set; }
+  /**
+   * Gets a child {@link DomElement} of {@link element} referenced in
+   * {@link nodes_index}.
+   */
+  public virtual DomElement? get_item (int index) throws GLib.Error {
+    var e = element.child_nodes.get (index);
+    if (e != null)
+      if (!(e is GomElement))
+        throw new DomError.INVALID_NODE_TYPE_ERROR
+              (_("Referenced object's type is invalid. Should be a GXmlGomElement"));
+    return (DomElement?) e;
+  }
+  /**
+   * Number of items referenced in {@link nodes_index}
+   */
+  public virtual int length { get { return (int) nodes_index.length; } }
+}
+
+public class GXml.GomArrayList : Object, GomCollection {
+  protected List<int> _nodes_index = new List<int> ();
+  protected GomElement _element;
+  protected string _element_name;
+  public List<int> nodes_index { get { return _nodes_index; } }
+  public DomElement element {
+    get { return _element; }
+    construct set {
+      if (value is GomElement)
+        _element = value as GomElement;
+      else
+        GLib.warning (_("Invalid element type only GXmlGomElement is supported"));
+    }
+  }
+  public string element_name {
+    get { return _element_name; } construct set { _element_name = value; }
+  }
+
+  /**
+   * Adds an {@link DomElement} of type {@link GomObject} as a child of
+   * {@link element}
+   */
+  public void add (DomElement node) throws GLib.Error {
+    if (!(node is GomElement))
+      throw new DomError.INVALID_NODE_TYPE_ERROR
+                (_("Invalid atempt to add unsupported type. Only GXmlGomElement is supported"));
+    if (node.owner_document != _element.owner_document)
+      throw new DomError.HIERARCHY_REQUEST_ERROR
+                (_("Invalid atempt to add a node with a different parent document"));
+    _element.append_child (node);
+    if (_element.child_nodes.size == 0)
+      throw new DomError.QUOTA_EXCEEDED_ERROR
+                (_("Invalid atempt to add a node with a different parent document"));
+    _nodes_index.append (_element.child_nodes.size - 1);
+  }
+}
diff --git a/gxml/Makefile.am b/gxml/Makefile.am
index 602281d..2cc4a37 100644
--- a/gxml/Makefile.am
+++ b/gxml/Makefile.am
@@ -88,6 +88,7 @@ sources = \
        GomNode.vala \
        GomText.vala \
        GomObject.vala \
+       GomCollections.vala \
        Parser.vala \
        XParser.vala \
        $(NULL)