More code contracts.

3 files changed, 112 insertions, 0 deletions

diff --git a/src/DotNetOpenAuth/OpenId/Extensions/AliasManager.cs b/src/DotNetOpenAuth/OpenId/Extensions/AliasManager.cs
index f5a541d..0a84266 100644
--- a/src/DotNetOpenAuth/OpenId/Extensions/AliasManager.cs
+++ b/src/DotNetOpenAuth/OpenId/Extensions/AliasManager.cs
@@ -68,6 +68,8 @@ namespace DotNetOpenAuth.OpenId.Extensions {
 		/// <param name="typeUris">The type URIs to create aliases for.</param>
 		/// <param name="preferredTypeUriToAliases">An optional dictionary of URI/alias pairs that suggest preferred aliases to use if available for certain type URIs.</param>
 		public void AssignAliases(IEnumerable<string> typeUris, IDictionary<string, string> preferredTypeUriToAliases) {
+			Contract.Requires<ArgumentNullException>(typeUris != null);
+
 			// First go through the actually used type URIs and see which ones have matching preferred aliases.
 			if (preferredTypeUriToAliases != null) {
 				foreach (string typeUri in typeUris) {
diff --git a/src/DotNetOpenAuth/OpenId/Messages/IOpenIdMessageExtension.cs b/src/DotNetOpenAuth/OpenId/Messages/IOpenIdMessageExtension.cs
index 95080e6..57233ac 100644
--- a/src/DotNetOpenAuth/OpenId/Messages/IOpenIdMessageExtension.cs
+++ b/src/DotNetOpenAuth/OpenId/Messages/IOpenIdMessageExtension.cs
@@ -7,6 +7,7 @@
 namespace DotNetOpenAuth.OpenId.Messages {
 	using System;
 	using System.Collections.Generic;
+	using System.Diagnostics.Contracts;
 	using System.Linq;
 	using System.Text;
 	using DotNetOpenAuth.Messaging;
@@ -19,6 +20,7 @@ namespace DotNetOpenAuth.OpenId.Messages {
 	/// [<see cref="SerializableAttribute"/>] to allow serializing state servers
 	/// to cache messages, particularly responses.
 	/// </remarks>
+	[ContractClass(typeof(IOpenIdMessageExtensionContract))]
 	public interface IOpenIdMessageExtension : IExtensionMessage {
 		/// <summary>
 		/// Gets the TypeURI the extension uses in the OpenID protocol and in XRDS advertisements.
@@ -51,4 +53,110 @@ namespace DotNetOpenAuth.OpenId.Messages {
 		/// </value>
 		bool IsSignedByRemoteParty { get; set; }
 	}
+
+	/// <summary>
+	/// Code contract class for the IOpenIdMessageExtension interface.
+	/// </summary>
+	[ContractClassFor(typeof(IOpenIdMessageExtension))]
+	internal class IOpenIdMessageExtensionContract : IOpenIdMessageExtension {
+		/// <summary>
+		/// Prevents a default instance of the <see cref="IOpenIdMessageExtensionContract"/> class from being created.
+		/// </summary>
+		private IOpenIdMessageExtensionContract() {
+		}
+
+		#region IOpenIdMessageExtension Members
+
+		/// <summary>
+		/// Gets the TypeURI the extension uses in the OpenID protocol and in XRDS advertisements.
+		/// </summary>
+		string IOpenIdMessageExtension.TypeUri {
+			get {
+				Contract.Ensures(!String.IsNullOrEmpty(Contract.Result<string>()));
+				throw new NotImplementedException();
+			}
+		}
+
+		/// <summary>
+		/// Gets the additional TypeURIs that are supported by this extension, in preferred order.
+		/// May be empty if none other than <see cref="IOpenIdMessageExtension.TypeUri"/> is supported, but
+		/// should not be null.
+		/// </summary>
+		/// <remarks>
+		/// Useful for reading in messages with an older version of an extension.
+		/// The value in the <see cref="IOpenIdMessageExtension.TypeUri"/> property is always checked before
+		/// trying this list.
+		/// If you do support multiple versions of an extension using this method,
+		/// consider adding a CreateResponse method to your request extension class
+		/// so that the response can have the context it needs to remain compatible
+		/// given the version of the extension in the request message.
+		/// The <see cref="Extensions.SimpleRegistration.ClaimsRequest.CreateResponse"/> for an example.
+		/// </remarks>
+		IEnumerable<string> IOpenIdMessageExtension.AdditionalSupportedTypeUris {
+			get {
+				Contract.Ensures(Contract.Result<IEnumerable<string>>() != null);
+				throw new NotImplementedException();
+			}
+		}
+
+		/// <summary>
+		/// Gets or sets a value indicating whether this extension was
+		/// signed by the sender.
+		/// </summary>
+		/// <value>
+		/// 	<c>true</c> if this instance is signed by the sender; otherwise, <c>false</c>.
+		/// </value>
+		bool IOpenIdMessageExtension.IsSignedByRemoteParty {
+			get { throw new NotImplementedException(); }
+			set { throw new NotImplementedException(); }
+		}
+
+		#endregion
+
+		#region IMessage Members
+
+		/// <summary>
+		/// Gets the version of the protocol or extension this message is prepared to implement.
+		/// </summary>
+		/// <remarks>
+		/// Implementations of this interface should ensure that this property never returns null.
+		/// </remarks>
+		Version IMessage.Version {
+			get {
+				Contract.Ensures(Contract.Result<Version>() != null);
+				throw new NotImplementedException();
+			}
+		}
+
+		/// <summary>
+		/// Gets the extra, non-standard Protocol parameters included in the message.
+		/// </summary>
+		/// <remarks>
+		/// Implementations of this interface should ensure that this property never returns null.
+		/// </remarks>
+		IDictionary<string, string> IMessage.ExtraData {
+			get {
+				Contract.Ensures(Contract.Result<IDictionary<string, string>>() != null);
+				throw new NotImplementedException();
+			}
+		}
+
+		/// <summary>
+		/// Checks the message state for conformity to the protocol specification
+		/// and throws an exception if the message is invalid.
+		/// </summary>
+		/// <remarks>
+		/// 	<para>Some messages have required fields, or combinations of fields that must relate to each other
+		/// in specialized ways.  After deserializing a message, this method checks the state of the
+		/// message to see if it conforms to the protocol.</para>
+		/// 	<para>Note that this property should <i>not</i> check signatures or perform any state checks
+		/// outside this scope of this particular message.</para>
+		/// </remarks>
+		/// <exception cref="ProtocolException">Thrown if the message is invalid.</exception>
+		void IMessage.EnsureValidMessage() {
+			throw new NotImplementedException();
+		}
+
+		#endregion
+	}
 }
diff --git a/src/DotNetOpenAuth/OpenId/ProviderEndpointDescription.cs b/src/DotNetOpenAuth/OpenId/ProviderEndpointDescription.cs
index c317948..4cfbac5 100644
--- a/src/DotNetOpenAuth/OpenId/ProviderEndpointDescription.cs
+++ b/src/DotNetOpenAuth/OpenId/ProviderEndpointDescription.cs
@@ -112,6 +112,7 @@ namespace DotNetOpenAuth.OpenId {
 		/// the extension in the request and see if a response comes back for that extension.
 		/// </remarks>
 		public bool IsExtensionSupported<T>() where T : IOpenIdMessageExtension, new() {
+			ErrorUtilities.VerifyOperation(this.Capabilities != null, OpenIdStrings.ExtensionLookupSupportUnavailable);
 			T extension = new T();
 			return this.IsExtensionSupported(extension);
 		}
@@ -131,6 +132,7 @@ namespace DotNetOpenAuth.OpenId {
 		/// the extension in the request and see if a response comes back for that extension.
 		/// </remarks>
 		public bool IsExtensionSupported(Type extensionType) {
+			ErrorUtilities.VerifyOperation(this.Capabilities != null, OpenIdStrings.ExtensionLookupSupportUnavailable);
 			var extension = (IOpenIdMessageExtension)Activator.CreateInstance(extensionType);
 			return this.IsExtensionSupported(extension);
 		}