1 files changed, 87 insertions, 0 deletions
diff --git a/tools/Sandcastle/Source/BuildAssembler/BuildComponents/IfThenComponent.cs b/tools/Sandcastle/Source/BuildAssembler/BuildComponents/IfThenComponent.cs
new file mode 100644
index 0000000..e44c0f2
--- /dev/null
+++ b/tools/Sandcastle/Source/BuildAssembler/BuildComponents/IfThenComponent.cs
@@ -0,0 +1,87 @@
+// Copyright © Microsoft Corporation.
+// This source file is subject to the Microsoft Permissive License.
+// See http://www.microsoft.com/resources/sharedsource/licensingbasics/sharedsourcelicenses.mspx.
+// All other rights reserved.
+
+using System;
+using System.Collections.Generic;
+using System.Configuration;
+using System.Xml;
+using System.Xml.XPath;
+using System.Xml.Xsl;
+
+using System.Reflection;
+
+namespace Microsoft.Ddue.Tools {
+
+	public class IfThenComponent : BuildComponent {
+
+		private XPathExpression condition;
+
+		private IEnumerable<BuildComponent> true_branch = new List<BuildComponent>();
+
+		private IEnumerable<BuildComponent> false_branch = new List<BuildComponent>();
+
+		public IfThenComponent (BuildAssembler assembler, XPathNavigator configuration) : base(assembler, configuration) {
+			
+			// get the condition
+			XPathNavigator if_node = configuration.SelectSingleNode("if");
+			if (if_node == null) throw new ConfigurationErrorsException("You must specify a condition using the <if> element.");
+			string condition_xpath = if_node.GetAttribute("condition", String.Empty);
+			if (String.IsNullOrEmpty(condition_xpath)) throw new ConfigurationErrorsException();
+			condition = XPathExpression.Compile(condition_xpath);
+
+			// construct the true branch
+			XPathNavigator then_node = configuration.SelectSingleNode("then");
+			if (then_node != null) true_branch = BuildAssembler.LoadComponents(then_node);
+
+			// construct the false branch
+			XPathNavigator else_node = configuration.SelectSingleNode("else");
+			if (else_node != null) false_branch = BuildAssembler.LoadComponents(else_node);
+
+            // keep a pointer to the context for future use
+            context = assembler.Context;
+
+		}
+
+		private BuildContext context;
+
+		public override void Apply (XmlDocument document, string key) {
+
+            // set up the test
+			context["key"] = key;
+			XPathExpression test = condition.Clone();
+			test.SetContext(context.XsltContext);
+
+			// evaluate the condition
+			bool result = (bool) document.CreateNavigator().Evaluate(test);
+
+			// on the basis of the condition, execute either the true or the false branch
+			if (result) {
+				foreach (BuildComponent component in true_branch) {
+					component.Apply(document, key);
+				}
+			} else {
+				foreach (BuildComponent component in false_branch) {
+					component.Apply(document, key);
+				}
+			}
+
+		}
+
+        protected override void Dispose(bool disposing) {
+            if (disposing) {
+                foreach (BuildComponent component in true_branch) {
+                    component.Dispose();
+                }
+                foreach (BuildComponent component in false_branch) {
+                    component.Dispose();
+                }
+            }
+            base.Dispose(disposing);
+        }
+
+	}
+
+
+}
+\ No newline at end of file