1 files changed, 68 insertions, 0 deletions
diff --git a/tools/Sandcastle/Source/BuildAssembler/BuildComponents/ComputeHashComponent.cs b/tools/Sandcastle/Source/BuildAssembler/BuildComponents/ComputeHashComponent.cs
new file mode 100644
index 0000000..37755ab
--- /dev/null
+++ b/tools/Sandcastle/Source/BuildAssembler/BuildComponents/ComputeHashComponent.cs
@@ -0,0 +1,68 @@
+using System;
+using System.Collections.Generic;
+using System.Security.Cryptography;
+using System.Text;
+using System.Xml;
+using System.Xml.XPath;
+
+
+namespace Microsoft.Ddue.Tools {
+
+	internal class HashComputation {
+
+		public HashComputation (string input, string output) {
+			Input = XPathExpression.Compile(input);
+			Output = XPathExpression.Compile(output);
+		}
+
+		public XPathExpression Input;
+		public XPathExpression Output;
+
+	}
+
+	public class ComputeHashComponent : BuildComponent {
+
+		public ComputeHashComponent (XPathNavigator configuration) : base(configuration) {
+
+			if (configuration == null) throw new ArgumentNullException("configuraton");
+
+			XPathNodeIterator hash_nodes = configuration.Select("hash");
+			foreach (XPathNavigator hash_node in hash_nodes) {
+				string input_xpath = hash_node.GetAttribute("input", String.Empty);
+				string output_xpath = hash_node.GetAttribute("output", String.Empty);
+				computations.Add( new HashComputation(input_xpath, output_xpath) );
+			}
+
+		}
+
+		// A list of the hash computations to do
+
+		private List<HashComputation> computations = new List<HashComputation>();
+
+		// Logic to compute a unique hash of a comment id string
+
+		private static Guid ComputeHash (string key) {
+			byte[] input = Encoding.UTF8.GetBytes(key);
+			byte[] output = md5.ComputeHash(input);
+			return( new Guid(output) );
+		}
+
+		private static HashAlgorithm md5 = new MD5CryptoServiceProvider();
+
+		// The actual action of the component
+
+		public override void Apply (XmlDocument document, string key) {
+
+			Guid id = ComputeHash(key);
+
+			foreach (HashComputation computation in computations) {
+				XPathNavigator output = document.CreateNavigator().SelectSingleNode(computation.Output);
+				if (output == null) continue;
+				output.SetValue(id.ToString());
+			}
+
+		}
+
+	}
+
+}