cannam@62: /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
cannam@62: 
cannam@62: /*
cannam@62:     QM DSP Library
cannam@62: 
cannam@62:     Centre for Digital Music, Queen Mary, University of London.
cannam@62:     This file copyright Chris Cannam, used with permission.
cannam@62: */
cannam@62: 
cannam@62: #ifndef _THREAD_H_
cannam@62: #define _THREAD_H_
cannam@62: 
cannam@62: #ifdef _WIN32
cannam@62: #include <windows.h>
cannam@62: #else /* !_WIN32 */
cannam@62: #ifdef USE_PTHREADS
cannam@62: #include <pthread.h>
cannam@62: #endif /* USE_PTHREADS */
cannam@62: #endif /* !_WIN32 */
cannam@62: 
cannam@62: #include <string>
cannam@62: 
cannam@62: //#define DEBUG_THREAD 1
cannam@62: //#define DEBUG_MUTEX 1
cannam@62: //#define DEBUG_CONDITION 1
cannam@62: 
cannam@62: class Thread
cannam@62: {
cannam@62: public:
cannam@62: #ifdef _WIN32
cannam@62:     typedef HANDLE Id;
cannam@62: #else
cannam@62: #ifdef USE_PTHREADS
cannam@62:     typedef pthread_t Id;
cannam@62: #endif
cannam@62: #endif
cannam@62: 
cannam@62:     Thread();
cannam@62:     virtual ~Thread();
cannam@62: 
cannam@62:     Id id();
cannam@62: 
cannam@62:     void start();
cannam@62:     void wait();
cannam@62: 
cannam@62:     static bool threadingAvailable();
cannam@62: 
cannam@62: protected:
cannam@62:     virtual void run() = 0;
cannam@62: 
cannam@62: private:
cannam@62: #ifdef _WIN32
cannam@62:     HANDLE m_id;
cannam@62:     bool m_extant;
cannam@62:     static DWORD WINAPI staticRun(LPVOID lpParam);
cannam@62: #else
cannam@62: #ifdef USE_PTHREADS
cannam@62:     pthread_t m_id;
cannam@62:     bool m_extant;
cannam@62:     static void *staticRun(void *);
cannam@62: #endif
cannam@62: #endif
cannam@62: };
cannam@62: 
cannam@62: class Mutex
cannam@62: {
cannam@62: public:
cannam@62:     Mutex();
cannam@62:     ~Mutex();
cannam@62: 
cannam@62:     void lock();
cannam@62:     void unlock();
cannam@62:     bool trylock();
cannam@62: 
cannam@62: private:
cannam@62: #ifdef _WIN32
cannam@62:     HANDLE m_mutex;
cannam@62: #ifndef NO_THREAD_CHECKS
cannam@62:     DWORD m_lockedBy;
cannam@62: #endif
cannam@62: #else
cannam@62: #ifdef USE_PTHREADS
cannam@62:     pthread_mutex_t m_mutex;
cannam@62: #ifndef NO_THREAD_CHECKS
cannam@62:     pthread_t m_lockedBy;
cannam@62:     bool m_locked;
cannam@62: #endif
cannam@62: #endif
cannam@62: #endif
cannam@62: };
cannam@62: 
cannam@62: class MutexLocker
cannam@62: {
cannam@62: public:
cannam@62:     MutexLocker(Mutex *);
cannam@62:     ~MutexLocker();
cannam@62: 
cannam@62: private:
cannam@62:     Mutex *m_mutex;
cannam@62: };
cannam@62: 
cannam@62: class Condition
cannam@62: {
cannam@62: public:
cannam@62:     Condition(std::string name);
cannam@62:     ~Condition();
cannam@62: 
cannam@63:     // Condition bundles a pthread-style condition variable and mutex
cannam@63:     // into one class.
cannam@62: 
cannam@63:     // To wait on a condition, call lock(), test termination variables
cannam@63:     // as appropriate, and then wait().  The condition will be
cannam@63:     // unlocked for the duration of the wait() call, which will end
cannam@63:     // when the condition is signalled.  The condition will be locked
cannam@63:     // again when wait() returns.
cannam@63:     //
cannam@63:     // To signal a condition, call signal().  If the waiting thread
cannam@63:     // will be performing tests between its own lock() and wait(),
cannam@63:     // then the signalling thread should also lock() before it signals
cannam@63:     // (and then unlock afterwards).  If the signalling thread always
cannam@63:     // locks the mutex during signalling, then the waiting thread
cannam@63:     // knows that signals will only happen during wait() and not be
cannam@63:     // missed at other times.
cannam@63: 
cannam@62:     void lock();
cannam@62:     void unlock();
cannam@62:     void wait(int us = 0);
cannam@62: 
cannam@62:     void signal();
cannam@62:     
cannam@62: private:
cannam@62: 
cannam@62: #ifdef _WIN32
cannam@62:     HANDLE m_mutex;
cannam@62:     HANDLE m_condition;
cannam@62:     bool m_locked;
cannam@62: #else
cannam@62: #ifdef USE_PTHREADS
cannam@62:     pthread_mutex_t m_mutex;
cannam@62:     pthread_cond_t m_condition;
cannam@62:     bool m_locked;
cannam@62: #endif
cannam@62: #endif
cannam@62: #ifdef DEBUG_CONDITION
cannam@62:     std::string m_name;
cannam@62: #endif
cannam@62: };
cannam@62: 
cannam@63: class AsynchronousTask : public Thread
cannam@63: {
cannam@63: public:
cannam@63:     AsynchronousTask() :
cannam@63:         m_todo("AsynchronousTask: task to perform"),
cannam@63:         m_done("AsynchronousTask: task complete"),
cannam@63:         m_inTask(false),
cannam@63:         m_finishing(false)
cannam@63:     {
cannam@63:         start();
cannam@63:     }
cannam@63:     virtual ~AsynchronousTask()
cannam@63:     {
cannam@63:         m_finishing = true;
cannam@63:         m_todo.signal();
cannam@63:         wait();
cannam@63:     }
cannam@63: 
cannam@63:     // subclass must provide methods to request task and obtain
cannam@63:     // results
cannam@63: 
cannam@63: protected:
cannam@63:     void startTask() {
cannam@63:         m_todo.lock();
cannam@63:         m_inTask = true;
cannam@63:         m_todo.signal();
cannam@63:         m_done.lock();
cannam@63:         m_todo.unlock();
cannam@63:     }
cannam@63:     void awaitTask() {
cannam@63:         while (m_inTask) m_done.wait();
cannam@63:         m_done.unlock();
cannam@63:     }
cannam@63: 
cannam@63:     virtual void performTask() = 0;
cannam@63:     
cannam@63: private:
cannam@63:     virtual void run() {
cannam@63:         m_todo.lock();
cannam@63:         while (!m_finishing) {
cannam@63:             while (!m_inTask && !m_finishing) m_todo.wait();
cannam@63:             if (m_finishing) break;
cannam@63:             if (m_inTask) {
cannam@63:                 performTask();
cannam@63:                 m_inTask = false;
cannam@63:                 m_done.signal();
cannam@63:             }
cannam@63:         }
cannam@63:         m_todo.unlock();
cannam@63:     }
cannam@63: 
cannam@63:     Condition m_todo;
cannam@63:     Condition m_done;
cannam@63:     bool m_inTask;
cannam@63:     bool m_finishing;
cannam@63: };
cannam@63: 
cannam@62: #endif