generator: Add option to validate GAPI XML against an XSD schema

With a new --schema option, you can specify the path to an XSD file, and
all GAPI XML files will be validated against this schema, including the
files given through the --include option.

generator/CodeGenerator.cs

@@ -24,6 +24,7 @@ namespace GtkSharp.Generation {
 
 	using System;
 	using System.Collections.Generic;
+	using System.IO;
 	using System.Xml;
 
 	public class CodeGenerator  {
@@ -36,6 +37,7 @@ namespace GtkSharp.Generation {
 			string glue_filename = "";
 			string glue_includes = "";
 			string gluelib_name = "";
+			string schema_name = "";
 
 			SymbolTable table = SymbolTable.Table;
 			var gens = new List<IGeneratable> ();
@@ -59,6 +61,8 @@ namespace GtkSharp.Generation {
 				{ "gluelib-name=", "Name of the C library into which the C glue code will be compiled. " +
 					"Used to generated correct DllImport attributes.",
 					(string v) => { gluelib_name = v; } },
+				{ "schema=", "Validate all GAPI XML files against this XSD schema.",
+					(string v) => { schema_name  = v; } },
 				{ "h|help",  "Show this message and exit",
 					v => show_help = v != null },
 			};
@@ -90,14 +94,19 @@ namespace GtkSharp.Generation {
 				return 0;
 			}
 
+			if (!String.IsNullOrEmpty (schema_name) && !File.Exists (schema_name)) {
+				Console.WriteLine ("WARNING: Could not find schema file at '{0}', no validation will be done.", schema_name);
+				schema_name = null;
+			}
+
 			Parser p = new Parser ();
 			foreach (string include in includes) {
-				IGeneratable[] curr_gens = p.Parse (include);
+				IGeneratable[] curr_gens = p.Parse (include, schema_name);
 				table.AddTypes (curr_gens);
 			}
 
 			foreach (string filename in filenames) {
-				IGeneratable[] curr_gens = p.Parse (filename);
+				IGeneratable[] curr_gens = p.Parse (filename, schema_name);
 				table.AddTypes (curr_gens);
 				gens.AddRange (curr_gens);
 			}

generator/Parser.cs

@@ -26,17 +26,28 @@ namespace GtkSharp.Generation {
 	using System.Collections.Generic;
 	using System.IO;
 	using System.Xml;
+	using System.Xml.Schema;
 
 	public class Parser  {
 		const int curr_parser_version = 2;
 
-		private XmlDocument Load (string filename)
+		private XmlDocument Load (string filename, string schema_file)
 		{
 			XmlDocument doc = new XmlDocument ();
 
 			try {
+				XmlReaderSettings settings = new XmlReaderSettings ();
+				if (!String.IsNullOrEmpty (schema_file)) {
+					settings.Schemas.Add (null, schema_file);
+					settings.ValidationType = ValidationType.Schema;
+					settings.ValidationFlags |= XmlSchemaValidationFlags.ReportValidationWarnings;
+					settings.ValidationEventHandler += ValidationEventHandler;
+				}
+
 				Stream stream = File.OpenRead (filename);
-				doc.Load (stream);
+				XmlReader reader = XmlReader.Create (stream, settings);
+				doc.Load (reader);
+
 				stream.Close ();
 			} catch (XmlException e) {
 				Console.WriteLine ("Invalid XML file.");
@@ -47,9 +58,27 @@ namespace GtkSharp.Generation {
 			return doc;
 		}
 
+		private void ValidationEventHandler(object sender, ValidationEventArgs e)
+		{
+			switch (e.Severity)
+			{
+			case XmlSeverityType.Error:
+				Console.WriteLine("Error: {0}", e.Message);
+				break;
+			case XmlSeverityType.Warning:
+				Console.WriteLine("Warning: {0}", e.Message);
+				break;
+			}
+		}
+
 		public IGeneratable[] Parse (string filename)
 		{
-			XmlDocument doc = Load (filename);
+			return Parse (filename, null);
+		}
+
+		public IGeneratable[] Parse (string filename, string schema_file)
+		{
+			XmlDocument doc = Load (filename, schema_file);
 			if (doc == null)
 				return null;