THRIFT-1272 add subclass of ReadWriteMutex that avoids writer
starvation
Patch: Dave Watson
git-svn-id: https://svn.apache.org/repos/asf/thrift/trunk@1213067 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/lib/cpp/src/concurrency/Mutex.h b/lib/cpp/src/concurrency/Mutex.h
index 847aaf6..1763b5c 100644
--- a/lib/cpp/src/concurrency/Mutex.h
+++ b/lib/cpp/src/concurrency/Mutex.h
@@ -101,6 +101,25 @@
boost::shared_ptr<impl> impl_;
};
+/**
+ * A ReadWriteMutex that guarantees writers will not be starved by readers:
+ * When a writer attempts to acquire the mutex, all new readers will be
+ * blocked from acquiring the mutex until the writer has acquired and
+ * released it. In some operating systems, this may already be guaranteed
+ * by a regular ReadWriteMutex.
+ */
+class NoStarveReadWriteMutex : public ReadWriteMutex {
+public:
+ NoStarveReadWriteMutex();
+
+ virtual void acquireRead() const;
+ virtual void acquireWrite() const;
+
+private:
+ Mutex mutex_;
+ mutable volatile bool writerWaiting_;
+};
+
class Guard : boost::noncopyable {
public:
Guard(const Mutex& value, int64_t timeout = 0) : mutex_(&value) {