1 files changed, 156 insertions, 0 deletions
diff --git a/src/DotNetOpenAuth.Messaging/Messaging/Bindings/MemoryCryptoKeyStore.cs b/src/DotNetOpenAuth.Messaging/Messaging/Bindings/MemoryCryptoKeyStore.cs
new file mode 100644
index 0000000..63d1953
--- /dev/null
+++ b/src/DotNetOpenAuth.Messaging/Messaging/Bindings/MemoryCryptoKeyStore.cs
@@ -0,0 +1,156 @@
+//-----------------------------------------------------------------------
+// <copyright file="MemoryCryptoKeyStore.cs" company="Andrew Arnott">
+//     Copyright (c) Andrew Arnott. All rights reserved.
+// </copyright>
+//-----------------------------------------------------------------------
+
+namespace DotNetOpenAuth.Messaging.Bindings {
+	using System;
+	using System.Collections.Generic;
+	using System.Linq;
+
+	/// <summary>
+	/// A in-memory store of crypto keys.
+	/// </summary>
+	internal class MemoryCryptoKeyStore : ICryptoKeyStore {
+		/// <summary>
+		/// How frequently to check for and remove expired secrets.
+		/// </summary>
+		private static readonly TimeSpan cleaningInterval = TimeSpan.FromMinutes(30);
+
+		/// <summary>
+		/// An in-memory cache of decrypted symmetric keys.
+		/// </summary>
+		/// <remarks>
+		/// The key is the bucket name.  The value is a dictionary whose key is the handle and whose value is the cached key.
+		/// </remarks>
+		private readonly Dictionary<string, Dictionary<string, CryptoKey>> store = new Dictionary<string, Dictionary<string, CryptoKey>>(StringComparer.Ordinal);
+
+		/// <summary>
+		/// The last time the cache had expired keys removed from it.
+		/// </summary>
+		private DateTime lastCleaning = DateTime.UtcNow;
+
+		/// <summary>
+		/// Gets the key in a given bucket and handle.
+		/// </summary>
+		/// <param name="bucket">The bucket name.  Case sensitive.</param>
+		/// <param name="handle">The key handle.  Case sensitive.</param>
+		/// <returns>
+		/// The cryptographic key, or <c>null</c> if no matching key was found.
+		/// </returns>
+		public CryptoKey GetKey(string bucket, string handle) {
+			lock (this.store) {
+				Dictionary<string, CryptoKey> cacheBucket;
+				if (this.store.TryGetValue(bucket, out cacheBucket)) {
+					CryptoKey key;
+					if (cacheBucket.TryGetValue(handle, out key)) {
+						return key;
+					}
+				}
+			}
+
+			return null;
+		}
+
+		/// <summary>
+		/// Gets a sequence of existing keys within a given bucket.
+		/// </summary>
+		/// <param name="bucket">The bucket name.  Case sensitive.</param>
+		/// <returns>
+		/// A sequence of handles and keys, ordered by descending <see cref="CryptoKey.ExpiresUtc"/>.
+		/// </returns>
+		public IEnumerable<KeyValuePair<string, CryptoKey>> GetKeys(string bucket) {
+			lock (this.store) {
+				Dictionary<string, CryptoKey> cacheBucket;
+				if (this.store.TryGetValue(bucket, out cacheBucket)) {
+					return cacheBucket.ToList();
+				} else {
+					return Enumerable.Empty<KeyValuePair<string, CryptoKey>>();
+				}
+			}
+		}
+
+		/// <summary>
+		/// Stores a cryptographic key.
+		/// </summary>
+		/// <param name="bucket">The name of the bucket to store the key in.  Case sensitive.</param>
+		/// <param name="handle">The handle to the key, unique within the bucket.  Case sensitive.</param>
+		/// <param name="key">The key to store.</param>
+		/// <exception cref="CryptoKeyCollisionException">Thrown in the event of a conflict with an existing key in the same bucket and with the same handle.</exception>
+		public void StoreKey(string bucket, string handle, CryptoKey key) {
+			lock (this.store) {
+				Dictionary<string, CryptoKey> cacheBucket;
+				if (!this.store.TryGetValue(bucket, out cacheBucket)) {
+					this.store[bucket] = cacheBucket = new Dictionary<string, CryptoKey>(StringComparer.Ordinal);
+				}
+
+				if (cacheBucket.ContainsKey(handle)) {
+					throw new CryptoKeyCollisionException();
+				}
+
+				cacheBucket[handle] = key;
+
+				this.CleanExpiredKeysFromMemoryCacheIfAppropriate();
+			}
+		}
+
+		/// <summary>
+		/// Removes the key.
+		/// </summary>
+		/// <param name="bucket">The bucket name.  Case sensitive.</param>
+		/// <param name="handle">The key handle.  Case sensitive.</param>
+		public void RemoveKey(string bucket, string handle) {
+			lock (this.store) {
+				Dictionary<string, CryptoKey> cacheBucket;
+				if (this.store.TryGetValue(bucket, out cacheBucket)) {
+					cacheBucket.Remove(handle);
+				}
+			}
+		}
+
+		/// <summary>
+		/// Cleans the expired keys from memory cache if the cleaning interval has passed.
+		/// </summary>
+		private void CleanExpiredKeysFromMemoryCacheIfAppropriate() {
+			if (DateTime.UtcNow > this.lastCleaning + cleaningInterval) {
+				lock (this.store) {
+					if (DateTime.UtcNow > this.lastCleaning + cleaningInterval) {
+						this.ClearExpiredKeysFromMemoryCache();
+					}
+				}
+			}
+		}
+
+		/// <summary>
+		/// Weeds out expired keys from the in-memory cache.
+		/// </summary>
+		private void ClearExpiredKeysFromMemoryCache() {
+			lock (this.store) {
+				var emptyBuckets = new List<string>();
+				foreach (var bucketPair in this.store) {
+					var expiredKeys = new List<string>();
+					foreach (var handlePair in bucketPair.Value) {
+						if (handlePair.Value.ExpiresUtc < DateTime.UtcNow) {
+							expiredKeys.Add(handlePair.Key);
+						}
+					}
+
+					foreach (var expiredKey in expiredKeys) {
+						bucketPair.Value.Remove(expiredKey);
+					}
+
+					if (bucketPair.Value.Count == 0) {
+						emptyBuckets.Add(bucketPair.Key);
+					}
+				}
+
+				foreach (string emptyBucket in emptyBuckets) {
+					this.store.Remove(emptyBucket);
+				}
+
+				this.lastCleaning = DateTime.UtcNow;
+			}
+		}
+	}
+}