Connector/NET commit: r798 - branches/1.0/mysqlclient/common

[rburnett]

Added:
   branches/1.0/mysqlclient/common/Semaphore.cs
Log:
failed to add this file back when I fixed the connection pooling bug

Added: branches/1.0/mysqlclient/common/Semaphore.cs
===================================================================
--- branches/1.0/mysqlclient/common/Semaphore.cs	2007-07-20 20:18:10 UTC (rev 797)
+++ branches/1.0/mysqlclient/common/Semaphore.cs	2007-07-20 20:39:26 UTC (rev 798)
@@ -0,0 +1,82 @@
+// Copyright (C) 2004-2007 MySQL AB
+//
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License version 2 as published by
+// the Free Software Foundation
+//
+// There are special exceptions to the terms and conditions of the GPL 
+// as it is applied to this software. View the full text of the 
+// exception in file EXCEPTIONS in the directory of this software 
+// distribution.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 
+
+using System;
+using System.Threading;
+using System.Runtime.InteropServices;
+
+namespace MySql.Data.Common
+{
+    internal class Semaphore : WaitHandle
+    {
+        public Semaphore(int initialCount, int maximumCount)
+        {
+            SECURITY_ATTRIBUTES sa = new SECURITY_ATTRIBUTES();
+            IntPtr handle = CreateSemaphore(ref sa, initialCount, 
+                maximumCount, null);
+            if (handle.Equals(IntPtr.Zero))
+            {
+                throw new Exception("Unable to create semaphore");
+            }
+            base.Handle = handle;
+        }
+
+        public int Release()
+        {
+            IntPtr previous = IntPtr.Zero;
+            if (!ReleaseSemaphore(base.Handle, 1, previous))
+                throw new Exception("Unable to release semaphore");
+            return previous.ToInt32();
+        }
+
+        public override bool WaitOne(int millisecondsTimeout, bool exitContext)
+        {
+            if ((millisecondsTimeout < 0) && (millisecondsTimeout != -1))
+                throw new ArgumentOutOfRangeException("millisecondsTimeout");
+
+            if (exitContext)
+                throw new ArgumentException(null, "exitContext");
+
+            int result = WaitForSingleObject(Handle, millisecondsTimeout);
+            if (0 == result) return true;
+            return false;
+        }
+
+        [DllImport("kernel32.dll")]
+        static extern bool ReleaseSemaphore(IntPtr hSemaphore, 
+            int lReleaseCount, IntPtr lpPreviousCount);
+
+        [DllImport("kernel32.dll", SetLastError = true)]
+        private static extern IntPtr CreateSemaphore(
+            ref SECURITY_ATTRIBUTES securityAttributes, int initialCount, 
+            int maximumCount, string name);
+
+        [DllImport("kernel32.dll", SetLastError = true)]
+        private static extern int WaitForSingleObject(IntPtr handle, int millis);
+    }
+
+    [StructLayout(LayoutKind.Sequential)]
+    internal struct SECURITY_ATTRIBUTES
+    {
+        public int nLength;
+        public IntPtr lpSecurityDescriptor;
+        public int bInheritHandle;
+    }
+}