//Reading navigation map starting from <navMap> node
private static async Task <EpubNavigationMap> ReadNavigationMapAsync(XmlReader reader)
{
EpubNavigationMap result = new EpubNavigationMap();
bool mapFound = await reader.ReadToFollowingAsync("navMap", "http://www.daisy.org/z3986/2005/ncx/");
if (!mapFound)
{
throw new Exception("EPUB parsing error: navMap section not found in the .toc file.");
}
//reading till the </navMap> tag appearance
while (await reader.ReadAsync() && !(reader.NodeType == XmlNodeType.EndElement && reader.LocalName == "navMap"))
{
//We are looking for a top-level <navPoint> entries, considering that it could be any level of nesting:
if ((reader.LocalName == "navPoint") && (reader.NodeType != XmlNodeType.EndElement))
{
//We need to create a subreader space to limit the scope for each single navPoint
XmlReader subReader = reader.ReadSubtree();
EpubNavigationPoint navigationPoint = await ReadNavigationPointAsync(subReader);
//we reached the end of the top-level <navPoint> entry and it is time to add it to collection and to get rid of the sub-reader
result.Add(navigationPoint);
subReader.Dispose();
}
}
return(result);
}
private static EpubNavigationPoint ReadNavigationPoint(XElement navigationPointNode)
{
EpubNavigationPoint result = new EpubNavigationPoint();
foreach (XAttribute navigationPointNodeAttribute in navigationPointNode.Attributes())
{
string attributeValue = navigationPointNodeAttribute.Value;
switch (navigationPointNodeAttribute.Name.LocalName.ToLowerInvariant())
{
case "id":
result.Id = attributeValue;
break;
case "class":
result.Class = attributeValue;
break;
case "playOrder":
result.PlayOrder = attributeValue;
break;
}
}
if (String.IsNullOrWhiteSpace(result.Id))
{
throw new Exception("Incorrect EPUB navigation point: point ID is missing.");
}
result.NavigationLabels = new List <EpubNavigationLabel>();
result.ChildNavigationPoints = new List <EpubNavigationPoint>();
foreach (XElement navigationPointChildNode in navigationPointNode.Elements())
{
switch (navigationPointChildNode.Name.LocalName.ToLowerInvariant())
{
case "navlabel":
EpubNavigationLabel navigationLabel = ReadNavigationLabel(navigationPointChildNode);
result.NavigationLabels.Add(navigationLabel);
break;
case "content":
EpubNavigationContent content = ReadNavigationContent(navigationPointChildNode);
result.Content = content;
break;
case "navpoint":
EpubNavigationPoint childNavigationPoint = ReadNavigationPoint(navigationPointChildNode);
result.ChildNavigationPoints.Add(childNavigationPoint);
break;
}
}
if (!result.NavigationLabels.Any())
{
throw new Exception(String.Format("EPUB parsing error: navigation point {0} should contain at least one navigation label.", result.Id));
}
if (result.Content == null)
{
throw new Exception(String.Format("EPUB parsing error: navigation point {0} should contain content.", result.Id));
}
return(result);
}
private static EpubNavigationMap ReadNavigationMap(XElement navigationMapNode)
{
EpubNavigationMap result = new EpubNavigationMap();
foreach (XElement navigationPointNode in navigationMapNode.Elements())
{
if (String.Compare(navigationPointNode.Name.LocalName, "navPoint", StringComparison.OrdinalIgnoreCase) == 0)
{
EpubNavigationPoint navigationPoint = ReadNavigationPoint(navigationPointNode);
result.Add(navigationPoint);
}
}
return(result);
}
private static async Task <EpubNavigationPoint> ReadNavigationPointAsync(XmlReader reader)
{
EpubNavigationPoint result = new EpubNavigationPoint();
//we have to skip first entry as it could be empty after new sub-reader created
if (reader.NodeType == XmlNodeType.None)
{
await reader.ReadAsync();
}
//Now the pointer should point to the <navPoint> itself
while (reader.MoveToNextAttribute()) //Doing this we just passing through <navPoint> tag
{
switch (reader.LocalName.ToLowerInvariant()) //We have to collect all possible attributes from the <navPoint>
{
case "id":
result.Id = reader.Value;
break;
case "class":
result.Class = reader.Value;
break;
case "playorder":
result.PlayOrder = reader.Value;
break;
}
}
if (String.IsNullOrWhiteSpace(result.Id))
{
throw new Exception("Incorrect EPUB navigation point: point ID is missing");
}
result.NavigationLabels = new List <EpubNavigationLabel>();
result.ChildNavigationPoints = new List <EpubNavigationPoint>();
// We need to make sure that we will return pointer back to <navPoint> entry after reading all attributes
reader.MoveToElement();
//Now we are looking for subnodes - navLabel, content and sub-navPoints
while (await reader.ReadAsync())
{
if (reader.NodeType != XmlNodeType.EndElement)
{
switch (reader.LocalName.ToLowerInvariant())
{
case "navlabel":
EpubNavigationLabel navigationLabel = await ReadNavigationLabelAsync(reader); // Adding label to collection
result.NavigationLabels.Add(navigationLabel);
break;
case "content":
EpubNavigationContent content = await ReadNavigationContentAsync(reader); //Adding content to collection
result.Content = content;
break;
case "navpoint": //Yeep. Looks like we found a <navPoint> sub-node
XmlReader subTree = reader.ReadSubtree(); //Cooking a separate sub-reader scope for this node to separate it from the others siblings
EpubNavigationPoint childNavigationPoint = await ReadNavigationPointAsync(subTree); // I hate recursion...
//Adding a child to a collection
result.ChildNavigationPoints.Add(childNavigationPoint);
subTree.Dispose();
break;
}
}
}
;
return(result);
}
