Imported Upstream version 3.12.0

Former-commit-id: cf92446697332992ec36726e78eb8703e1f259d7

mcs/class/Mono.Security/Mono.Security.X509/X509Store.cs

@@ -97,10 +97,26 @@ namespace Mono.Security.X509 {
 		// methods
 
 		public void Clear () 
+		{
+			/* 
+			 * Both _certificates and _crls extend CollectionBase, whose Clear() method calls OnClear() and 
+			 * OnClearComplete(), which should be overridden in derivative classes. So we should not worry about
+			 * other threads that might be holding references to _certificates or _crls. They should be smart enough
+			 * to handle this gracefully.  And if not, it's their own fault.
+			 */
+			ClearCertificates ();
+			ClearCrls ();
+		}
+
+		void ClearCertificates()
 		{
 			if (_certificates != null)
 				_certificates.Clear ();
 			_certificates = null;
+		}
+
+		void ClearCrls ()
+		{
 			if (_crls != null)
 				_crls.Clear ();
 			_crls = null;
@@ -117,6 +133,7 @@ namespace Mono.Security.X509 {
 					fs.Write (data, 0, data.Length);
 					fs.Close ();
 				}
+				ClearCertificates ();	// We have modified the store on disk.  So forget the old state.
 			}
 #if !NET_2_1
 			// Try to save privateKey if available..
@@ -141,6 +158,7 @@ namespace Mono.Security.X509 {
 					byte[] data = crl.RawData;
 					fs.Write (data, 0, data.Length);
 				}
+				ClearCrls ();	// We have modified the store on disk.  So forget the old state.
 			}
 		}
 
@@ -149,6 +167,7 @@ namespace Mono.Security.X509 {
 			string filename = Path.Combine (_storePath, GetUniqueName (certificate));
 			if (File.Exists (filename)) {
 				File.Delete (filename);
+				ClearCertificates ();	// We have modified the store on disk.  So forget the old state.
 			}
 		}
 
@@ -157,6 +176,7 @@ namespace Mono.Security.X509 {
 			string filename = Path.Combine (_storePath, GetUniqueName (crl));
 			if (File.Exists (filename)) {
 				File.Delete (filename);
+				ClearCrls ();	// We have modified the store on disk.  So forget the old state.
 			}
 		}
 
@@ -236,8 +256,13 @@ namespace Mono.Security.X509 {
 				cspParams.Flags = CspProviderFlags.UseMachineKeyStore;
 			KeyPairPersistence kpp = new KeyPairPersistence (cspParams);
 
-			if (!kpp.Load ())
+			try {
+				if (!kpp.Load ())
+					return cert;
+			}
+			catch {
 				return cert;
+			}
 
 			if (cert.RSA != null)
 				cert.RSA = new RSACryptoServiceProvider (cspParams);