Initial population of CoreRT Runtime files.

1 files changed, 54 insertions, 0 deletions

diff --git a/src/Native/Runtime/RWLock.h b/src/Native/Runtime/RWLock.h
new file mode 100644
index 000000000..1684813fa
--- /dev/null
+++ b/src/Native/Runtime/RWLock.h
@@ -0,0 +1,54 @@
+//
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+class ReaderWriterLock
+{
+    volatile Int32  m_RWLock;       // lock used for R/W synchronization
+    Int32           m_spinCount;    // spin count for a reader waiting for a writer to release the lock
+
+#if 0
+    // used to prevent writers from being starved by readers
+    // we currently do not prevent writers from starving readers since writers 
+    // are supposed to be rare.
+    bool            m_WriterWaiting;
+#endif
+
+    bool TryAcquireReadLock();
+    bool TryAcquireWriteLock();
+
+public:
+    class ReadHolder
+    {
+        ReaderWriterLock * m_pLock;
+        bool               m_fLockAcquired;
+    public:
+        ReadHolder(ReaderWriterLock * pLock, bool fAcquireLock = true);
+        ~ReadHolder();
+    };
+
+    class WriteHolder
+    {
+        ReaderWriterLock * m_pLock;
+        bool               m_fLockAcquired;
+    public:
+        WriteHolder(ReaderWriterLock * pLock, bool fAcquireLock = true);
+        ~WriteHolder();
+    };
+
+    ReaderWriterLock();
+
+    void AcquireReadLock();
+    void ReleaseReadLock();
+
+    bool DangerousTryPulseReadLock();
+
+protected:
+    void AcquireWriteLock();
+    void ReleaseWriteLock();
+
+    void AcquireReadLockWorker();
+
+};
+