JavaScriptCore-903.tar.gz

[apple/javascriptcore.git] / wtf / ParallelJobsGeneric.h

diff --git a/wtf/ParallelJobsGeneric.h b/wtf/ParallelJobsGeneric.h
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+/*
+ * Copyright (C) 2011 University of Szeged
+ * Copyright (C) 2011 Gabor Loki <loki@webkit.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY UNIVERSITY OF SZEGED ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL UNIVERSITY OF SZEGED OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef ParallelJobsGeneric_h
+#define ParallelJobsGeneric_h
+
+#if ENABLE(THREADING_GENERIC)
+
+#include <wtf/RefCounted.h>
+#include <wtf/Threading.h>
+
+namespace WTF {
+
+static const unsigned int maxParallelThreads = 2;
+
+class ParallelEnvironment {
+    WTF_MAKE_FAST_ALLOCATED;
+public:
+    typedef void (*ThreadFunction)(void*);
+
+    ParallelEnvironment(ThreadFunction threadFunction, size_t sizeOfParameter, unsigned int requestedJobNumber) :
+        m_threadFunction(threadFunction),
+        m_sizeOfParameter(sizeOfParameter)
+    {
+        if (!requestedJobNumber || requestedJobNumber > maxParallelThreads)
+            requestedJobNumber = maxParallelThreads;
+
+        if (!s_threadPool)
+            s_threadPool = new Vector< RefPtr<ThreadPrivate> >();
+
+        // The main thread should be also a worker.
+        unsigned int maxNewThreads = requestedJobNumber - 1;
+
+        for (unsigned int i = 0; i < maxParallelThreads && m_threads.size() < maxNewThreads; ++i) {
+            if (s_threadPool->size() < i + 1)
+                s_threadPool->append(ThreadPrivate::create());
+
+            if ((*s_threadPool)[i]->tryLockFor(this))
+                m_threads.append((*s_threadPool)[i]);
+        }
+
+        m_numberOfJobs = m_threads.size() + 1;
+    }
+
+    int numberOfJobs()
+    {
+        return m_numberOfJobs;
+    }
+
+    void execute(unsigned char* parameters)
+    {
+        size_t i;
+        for (i = 0; i < m_threads.size(); ++i) {
+            m_threads[i]->execute(m_threadFunction, parameters);
+            parameters += m_sizeOfParameter;
+        }
+
+        // The work for the main thread
+        (*m_threadFunction)(parameters);
+
+        // Wait until all jobs are done.
+        for (i = 0; i < m_threads.size(); ++i)
+            m_threads[i]->waitForFinish();
+    }
+
+    class ThreadPrivate : public RefCounted<ThreadPrivate> {
+    public:
+        ThreadPrivate()
+            : m_threadID(0)
+            , m_running(false)
+            , m_parent(0)
+        {
+        }
+
+        bool tryLockFor(ParallelEnvironment*);
+
+        void execute(ThreadFunction, void*);
+
+        void waitForFinish();
+
+        static PassRefPtr<ThreadPrivate> create()
+        {
+            return adoptRef(new ThreadPrivate());
+        }
+
+        static void* workerThread(void*);
+
+    private:
+        ThreadIdentifier m_threadID;
+        bool m_running;
+        ParallelEnvironment* m_parent;
+
+        mutable Mutex m_mutex;
+        ThreadCondition m_threadCondition;
+
+        ThreadFunction m_threadFunction;
+        void* m_parameters;
+    };
+
+private:
+    ThreadFunction m_threadFunction;
+    size_t m_sizeOfParameter;
+    int m_numberOfJobs;
+
+    Vector< RefPtr<ThreadPrivate> > m_threads;
+    static Vector< RefPtr<ThreadPrivate> >* s_threadPool;
+};
+
+} // namespace WTF
+
+#endif // ENABLE(THREADING_GENERIC)
+
+
+#endif // ParallelJobsGeneric_h