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Imported Upstream version 4.8.0.309

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Former-commit-id: 5f9c6ae75f295e057a7d2971f3a6df4656fa8850
This commit is contained in:
Xamarin Public Jenkins (auto-signing)
2016-11-10 13:04:39 +00:00
parent ee1447783b
commit 94b2861243
4912 changed files with 390737 additions and 49310 deletions
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21
mcs/class/referencesource/System.Data/System/Data/SqlClient/SqlSymmetricKeyCache.cs
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@ -13,18 +13,19 @@ namespace System.Data.SqlClient {
using System.Diagnostics;
using System.Globalization;
using System.Linq;
using System.Runtime.Caching;
using System.Text;
/// <summary>
/// <para> Implements a cache of Symmetric Keys (once they are decrypted).Useful for rapidly decrypting multiple data values.</para>
/// </summary>
sealed internal class SqlSymmetricKeyCache {
private readonly ConcurrentDictionary<string,SqlClientSymmetricKey> _cache;
private readonly MemoryCache _cache;
private static readonly SqlSymmetricKeyCache _singletonInstance = new SqlSymmetricKeyCache();
private SqlSymmetricKeyCache () {
_cache = new ConcurrentDictionary<string, SqlClientSymmetricKey>(concurrencyLevel: 4 * Environment.ProcessorCount /* default value in ConcurrentDictionary*/, capacity: 2);
_cache = new MemoryCache("ColumnEncryptionKeyCache");
}
internal static SqlSymmetricKeyCache GetInstance () {
@ -54,10 +55,10 @@ namespace System.Data.SqlClient {
Debug.Assert(cacheLookupKey.Length <= capacity, "We needed to allocate a larger array");
#endif //DEBUG
encryptionKey = null;
// Lookup the key in cache
if (!_cache.TryGetValue(cacheLookupKey, out encryptionKey)) {
encryptionKey = _cache.Get(cacheLookupKey) as SqlClientSymmetricKey;
if (encryptionKey == null) {
Debug.Assert(SqlConnection.ColumnEncryptionTrustedMasterKeyPaths != null, @"SqlConnection.ColumnEncryptionTrustedMasterKeyPaths should not be null");
// Check against the trusted key paths
@ -96,9 +97,13 @@ namespace System.Data.SqlClient {
encryptionKey = new SqlClientSymmetricKey (plaintextKey);
// In case multiple threads reach here at the same time, the first one wins.
// The allocated memory will be reclaimed by Garbage Collector.
_cache.TryAdd(cacheLookupKey, encryptionKey);
// If the cache TTL is zero, don't even bother inserting to the cache.
if (SqlConnection.ColumnEncryptionKeyCacheTtl != TimeSpan.Zero) {
// In case multiple threads reach here at the same time, the first one wins.
// The allocated memory will be reclaimed by Garbage Collector.
DateTimeOffset expirationTime = DateTimeOffset.UtcNow.Add(SqlConnection.ColumnEncryptionKeyCacheTtl);
_cache.Add(cacheLookupKey, encryptionKey, expirationTime);
}
}
return true;