source: trunk/src/concurrent.h

//
// C++ Interface: concurrent
//
// Description:
//
//
// Author: Kohji Nakamura <k.nakamura@nao.ac.jp>, (C) 2012
//
// Copyright: See COPYING file that comes with this distribution
//
//
#ifndef CONCURRENT_H
#define CONCURRENT_H

#include <assert.h>
#include <pthread.h>

namespace concurrent {
        class PCException {
        public:
                virtual void raise() /*throw(PCException)*/ { throw *this; }
                virtual ~PCException() {}
        };

        //typedef void (*produce_t)(void *context) throw(PCException);
        //typedef void (*consume_t)(void *context) throw(PCException);

        class Mutex {
                pthread_mutex_t mutex;
        public:
                Mutex() throw(int);
                virtual ~Mutex();
                void lock() throw(int);
                /**
                 * Returns true if this thread could lock.
                 * Returns false if already locked.
                 */
                bool try_lock() throw(int);
                void unlock() throw(int);
        private:
                Mutex(Mutex const &other);
                Mutex &operator =(Mutex const &other);
        };

        class Semaphore {
                pthread_mutex_t mutex;
                pthread_cond_t cond;
                unsigned sem;
        public:
                explicit Semaphore(unsigned initial = 0U) throw(int);
                void up(unsigned amount = 1U) throw(int);
                void down(unsigned amount = 1U) throw(int);
                virtual ~Semaphore();
        private:
                Semaphore(Semaphore const &other);
                Semaphore &operator =(Semaphore const &other);
        };

        class FIFOException {
        public:
                virtual void raise() { throw *this; }
                virtual ~FIFOException() {}
        };

        class EmptyException {
        public:
                virtual void raise() { throw *this; }
                virtual ~EmptyException() {}
        };

        class FullException {
        public:
                virtual void raise() { throw *this; }
                virtual ~FullException() {}
        };

        template <class T, size_t N>
        class FIFO {
                T elements[N + 1]; // +1 to make an implementation simple.
                Mutex mutex;
                size_t head;
                size_t tail;

                size_t wrap(size_t n) {
                        return n % (N + 1);
                }

                void reset() {
                        head = tail = 0;
                }

        public:
                FIFO() {
                        assert(N > 0);
                        reset();
                }
                virtual ~FIFO() {
                        mutex.lock(); // wait until current lock is released.
                        mutex.unlock();
                }

                virtual void lock() {
                        mutex.lock();
                }

                /**
                 * Returns true if this thread could lock.
                 * Returns false if already locked.
                 */
                virtual bool try_lock() {
                        return mutex.try_lock();
                }

                virtual void unlock() {
                        mutex.unlock();
                }

                virtual void clear() {
                        reset();
                }

                virtual void put(T const &value) throw(FullException) {
                        size_t new_tail = wrap(tail + 1);
                        if (head == new_tail) {
                                throw FullException();
                        }
                        elements[tail] = value;
                        tail = new_tail;
                }

                virtual T get() throw(EmptyException) {
                        if (head == tail) {
                                throw EmptyException();
                        }
                        T result = elements[head];
                        head = wrap(head + 1);
                        return result;
                }

                /**
                 * Returns capacity size.
                 */
                virtual size_t size() const {
                        return N;
                }

                /**
                 * Returns number of elements in this FIFO.
                 */
                virtual size_t length() const {
                        size_t result = tail - head;
                        if (head > tail) {
                                result = N + 1 - (head - tail);
                        }
                        return result;
                }
        private:
                FIFO(FIFO const &other);
                FIFO &operator =(FIFO const &other);
        };

        class Broker {
        protected:
                enum ThreadSpec {
                        ProdAsMaster, ConsAsMaster, Unspecified
                };
                bool (*producer)(void *context) throw(PCException);
                void (*consumer)(void *context) throw(PCException);
                virtual void _run(void *context, unsigned do_ahead, ThreadSpec threadSpec) throw(PCException);
        public:
                Broker(bool (*producer)(void *context) throw(PCException),
                           void (*consumer)(void *context) throw(PCException));
                virtual ~Broker();
                static void enableNested();
                static void disableNested();
                static void setNestedState(bool nested);
                static bool getNestedState();

                virtual void run(void *context, unsigned do_ahead=1) throw(PCException);
                virtual void runProducerAsMasterThread(void *context, unsigned do_ahead=1) throw(PCException);
                virtual void runConsumerAsMasterThread(void *context, unsigned do_ahead=1) throw(PCException);
                virtual void runSequential(void *context) throw(PCException);
        };

#if 0
        template <class Context, class Product>
                class Producer {
        public:
                virtual Product produce(Context &ctx) throw(PCException) = 0;
                virtual ~Producer() {}
        };

        template <class Context, class Product>
                class Consumer {
        public:
                virtual void consume(Context &ctx, Product const&product) throw(PCException) = 0;
                virtual ~Consumer() {}
        };

class ProdCons {
 public:
        virtual ~ProdCons() {}

        virtual void runProducerAsMasterThread(void *context) throw(PCException) = 0;
        virtual void runConsumerAsMasterThread(void *context) throw(PCException) = 0;
        virtual void produce(void *context) throw(PCException) = 0;
        virtual void consume(void *context) throw(PCException) = 0;

        /**
         * <src>produce()</src> should  call this method to
         * let consumer to know it is ready.
         */
        virtual void ready() = 0;

        /**
         * Returns true if ready,
         * otherwise, finished or there was an error, returns false.
         *
         * <src>consume()</src> should call this method
         * to check if it is ready or not.
         * If false is returned, <src>isError()</src> or/and
         * <src>isFinished()</src> should be called to see the reason.
         */
        virtual bool waitForReady() = 0;

        /**
         * Returns true if <src>produce()</src> was finished,
         * otherwise returns false.
         */
        virtual bool isFinished() = 0;

        /**
         * <src>produce()</src>/<src>consume()</src> should call this method
         * to report error to <src>consume()</src>/<src>produce()</src>.
         */
        virtual void reportError(void *errorInfo) = 0;

        /**
         * Returns true and set errorInfo if <src>reportError()</src> is called,
         * otherwise returns false and set errorInfo to NULL.
         */
        virtual bool isError(void &*errorInfo) = 0;
};
#endif

}


#endif