src/common/Condition.h

/***************************************************************************
 *                                                                         *
 *   LinuxSampler - modular, streaming capable sampler                     *
 *                                                                         *
 *   Copyright (C) 2003, 2004 by Benno Senoner and Christian Schoenebeck   *
 *   Copyright (C) 2005 - 2017 Christian Schoenebeck                       *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the Free Software           *
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston,                 *
 *   MA  02111-1307  USA                                                   *
 ***************************************************************************/

#ifndef __CONDITION_H__
#define __CONDITION_H__

#include "Mutex.h"

#if defined(WIN32)
#include <windows.h>
#endif

namespace LinuxSampler {

#if defined(WIN32)
class ConditionInternal;
#endif

/**
 * Thread safe boolean condition.
 *
 * This is not meant to be used for real time operation!
 */
class Condition : public Mutex {
    public:
        /** @brief Constructor
         *
         * Creates a new thread safe condition variable.
         *
         * Note that the default bahavior of the underlying mutex is
         * @c NON_RECURSIVE by default, because in general if your design
         * requires the Condition object's lock state to be recursive instead,
         * then most probably this may result in dead locks or even undefined
         * behavior, because the underlying OS API for conditions may not be
         * compatible with recursive mutexes!
         *
         * @param bInitialCondition - optional: starting condition
         *                            (default = false)
         * @param mutexType - optional: fundamental behavior of underlying mutex
         *                    (default: @c NON_RECURSIVE)
         */
        Condition(bool bInitialCondition = false, Mutex::type_t mutexType = Mutex::NON_RECURSIVE);

        /**
         * Destructor
         */
        virtual ~Condition();

        /**
         * Blocks the calling thread if current condition equals
         * \a bCondition, in this case the calling thread will be blocked
         * until condition turns. Upon successful return the Condition
         * object is locked, so the calling thread can safely run it's
         * critical section and has to explicitly call Unlock() right after
         * it left it's critcal section.
         *
         * @e Note: If you don't provide a timeout value or if you provide a
         * timeout value of exactly 0s and 0ns, then this call will block
         * without any timeout, or in other words: @e infinity!
         *
         * @param bCondition         - block in case of this condition
         * @param TimeoutSeconds     - optional: max. wait time in seconds
         *                             (default: 0s)
         * @param TimeoutNanoSeconds - optional: max wait time in nano
         *                             seconds (default: 0ns)
         * @returns  0 on success, a value less than 0 if timeout exceeded
         */
        int WaitIf(bool bCondition, long TimeoutSeconds = 0L, long TimeoutNanoSeconds = 0L);

        /**
         * Same as WaitIf(), except that WaitAndUnlockIf() will unlock the
         * Condition object, so only use this call if you don't need to
         * enter a thread critical section, otherwise use WaitIf() instead!
         *
         * @e Note: If you don't provide a timeout value or if you provide a
         * timeout value of exactly 0s and 0ns, then this call will block
         * without any timeout, or in other words: @e infinity!
         *
         * @param bCondition         - block in case of this condition
         * @param TimeoutSeconds     - optional: max. wait time in seconds
         *                             (default: 0s)
         * @param TimeoutNanoSeconds - optional: max wait time in nano
         *                             seconds (default: 0ns)
         * @returns  0 on success, a value less than 0 if timeout exceeded
         * @see WaitIf()
         */
        int WaitAndUnlockIf(bool bCondition, long TimeoutSeconds = 0L, long TimeoutNanoSeconds = 0L);

        /**
         * You should use this method instead of WaitIf() in case the calling
         * thread already owns the Condition object's underlying mutex lock by
         * previously calling Lock() before. Essentially the only difference to
         * WaitIf() is that PreLockedWaitIf() does not call Lock() by itself.
         */
        int PreLockedWaitIf(bool bCondition, long TimeoutSeconds = 0L, long TimeoutNanoSeconds = 0L);

        /**
         * You should use this method instead of WaitAndUnlockIf() in case the
         * calling thread already owns the Condition object's underlying mutex
         * lock by previously calling Lock() before. Essentially the only
         * difference to WaitAndUnlockIf() is that PreLockedWaitAndUnlockIf()
         * does not call Lock() by itself.
         */
        int PreLockedWaitAndUnlockIf(bool bCondition, long TimeoutSeconds = 0L, long TimeoutNanoSeconds = 0L);

        /**
         * Set Condition object to \a bCondition. Upon change of the
         * condition, other threads waiting for \a bCondition will be
         * awakened. (Note the condition will not be locked for the calling
         * thread after this method returns!)
         *
         * @param bCondition - new condition
         */
        void Set(bool bCondition);

        /**
         * You should use this method instead of Set() in case the calling
         * thread already owns the Condition object's underlying mutex lock by
         * previously calling Lock() before. Essentially the only difference to
         * Set() is that PreLockedSet() does not call Lock() by itself.
         */
        void PreLockedSet(bool bCondition);

        /**
         * Returns the current boolean state of this condition object. This
         * method never blocks, it returns immediately and doesn't use any
         * system calls.
         *
         * @e Caution: this method is not thread safe! If you need to use
         * the condition state in a thread critical context you must call
         * @c Lock() and @c Unlock() respectively by yourself!
         */
        bool GetUnsafe();

#ifdef WIN32
        /**
         * Resets the condition. This is only needed on Windows, after
         * a thread waiting for a condition has been stopped with
         * StopThread.
         */
        void Reset();
#endif

    protected:
        int WaitIfInternal(bool bLock, bool bCondition, long TimeoutSeconds, long TimeoutNanoSeconds);
        void SetInternal(bool bLock, bool bCondition);

    #if defined(WIN32)
        friend class ConditionInternal;
        struct win32thread_cond_t {
            int waiters_count_; ///< Number of waiting threads.
            CRITICAL_SECTION waiters_count_lock_; ///< Serialize access to <waiters_count_>.
            HANDLE sema_; ///< Semaphore used to queue up threads waiting for the condition to become signaled.
            HANDLE waiters_done_; ///< An auto-reset event used by the broadcast/signal thread to wait for all the waiting thread(s) to wake up and be released from the semaphore.
            size_t was_broadcast_; ///< Keeps track of whether we were broadcasting or signaling. This allows us to optimize the code if we're just signaling.
        } __win32_true_condition, __win32_false_condition;
    #else
        pthread_cond_t __posix_true_condition;
        pthread_cond_t __posix_false_condition;
    #endif
        bool bCondition;
};

} // namespace LinuxSampler

#endif // __CONDITION_H__
1	schoenebeck	53	/***************************************************************************
2			* *
3			* LinuxSampler - modular, streaming capable sampler *
4			* *
5	schoenebeck	56	* Copyright (C) 2003, 2004 by Benno Senoner and Christian Schoenebeck *
6	schoenebeck	3290	* Copyright (C) 2005 - 2017 Christian Schoenebeck *
7	schoenebeck	53	* *
8			* This program is free software; you can redistribute it and/or modify *
9			* it under the terms of the GNU General Public License as published by *
10			* the Free Software Foundation; either version 2 of the License, or *
11			* (at your option) any later version. *
12			* *
13			* This program is distributed in the hope that it will be useful, *
14			* but WITHOUT ANY WARRANTY; without even the implied warranty of *
15			* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
16			* GNU General Public License for more details. *
17			* *
18			* You should have received a copy of the GNU General Public License *
19			* along with this program; if not, write to the Free Software *
20			* Foundation, Inc., 59 Temple Place, Suite 330, Boston, *
21			* MA 02111-1307 USA *
22			***************************************************************************/
23
24			#ifndef __CONDITION_H__
25			#define __CONDITION_H__
26
27			#include "Mutex.h"
28
29	senoner	1481	#if defined(WIN32)
30			#include <windows.h>
31	schoenebeck	1560	#endif
32	senoner	1481
33	schoenebeck	1560	namespace LinuxSampler {
34	senoner	1481
35	schoenebeck	1560	#if defined(WIN32)
36			class ConditionInternal;
37	senoner	1481	#endif
38
39	schoenebeck	53	/**
40			* Thread safe boolean condition.
41			*
42			* This is not meant to be used for real time operation!
43			*/
44			class Condition : public Mutex {
45			public:
46	schoenebeck	3290	/** @brief Constructor
47	schoenebeck	53	*
48	schoenebeck	3290	* Creates a new thread safe condition variable.
49			*
50			* Note that the default bahavior of the underlying mutex is
51			* @c NON_RECURSIVE by default, because in general if your design
52			* requires the Condition object's lock state to be recursive instead,
53			* then most probably this may result in dead locks or even undefined
54			* behavior, because the underlying OS API for conditions may not be
55			* compatible with recursive mutexes!
56			*
57	schoenebeck	53	* @param bInitialCondition - optional: starting condition
58			* (default = false)
59	schoenebeck	3290	* @param mutexType - optional: fundamental behavior of underlying mutex
60			* (default: @c NON_RECURSIVE)
61	schoenebeck	53	*/
62	schoenebeck	3290	Condition(bool bInitialCondition = false, Mutex::type_t mutexType = Mutex::NON_RECURSIVE);
63	schoenebeck	53
64			/**
65			* Destructor
66			*/
67	letz	502	virtual ~Condition();
68	schoenebeck	53
69			/**
70			* Blocks the calling thread if current condition equals
71			* \a bCondition, in this case the calling thread will be blocked
72			* until condition turns. Upon successful return the Condition
73			* object is locked, so the calling thread can safely run it's
74			* critical section and has to explicitly call Unlock() right after
75			* it left it's critcal section.
76			*
77	schoenebeck	1221	* @e Note: If you don't provide a timeout value or if you provide a
78			* timeout value of exactly 0s and 0ns, then this call will block
79	schoenebeck	1319	* without any timeout, or in other words: @e infinity!
80	schoenebeck	1221	*
81	schoenebeck	53	* @param bCondition - block in case of this condition
82			* @param TimeoutSeconds - optional: max. wait time in seconds
83			* (default: 0s)
84			* @param TimeoutNanoSeconds - optional: max wait time in nano
85			* seconds (default: 0ns)
86			* @returns 0 on success, a value less than 0 if timeout exceeded
87			*/
88			int WaitIf(bool bCondition, long TimeoutSeconds = 0L, long TimeoutNanoSeconds = 0L);
89
90			/**
91			* Same as WaitIf(), except that WaitAndUnlockIf() will unlock the
92			* Condition object, so only use this call if you don't need to
93			* enter a thread critical section, otherwise use WaitIf() instead!
94			*
95	schoenebeck	1221	* @e Note: If you don't provide a timeout value or if you provide a
96			* timeout value of exactly 0s and 0ns, then this call will block
97	schoenebeck	1319	* without any timeout, or in other words: @e infinity!
98	schoenebeck	1221	*
99	schoenebeck	53	* @param bCondition - block in case of this condition
100			* @param TimeoutSeconds - optional: max. wait time in seconds
101			* (default: 0s)
102			* @param TimeoutNanoSeconds - optional: max wait time in nano
103			* seconds (default: 0ns)
104			* @returns 0 on success, a value less than 0 if timeout exceeded
105			* @see WaitIf()
106			*/
107			int WaitAndUnlockIf(bool bCondition, long TimeoutSeconds = 0L, long TimeoutNanoSeconds = 0L);
108
109			/**
110	schoenebeck	3290	* You should use this method instead of WaitIf() in case the calling
111			* thread already owns the Condition object's underlying mutex lock by
112			* previously calling Lock() before. Essentially the only difference to
113			* WaitIf() is that PreLockedWaitIf() does not call Lock() by itself.
114			*/
115			int PreLockedWaitIf(bool bCondition, long TimeoutSeconds = 0L, long TimeoutNanoSeconds = 0L);
116
117			/**
118			* You should use this method instead of WaitAndUnlockIf() in case the
119			* calling thread already owns the Condition object's underlying mutex
120			* lock by previously calling Lock() before. Essentially the only
121			* difference to WaitAndUnlockIf() is that PreLockedWaitAndUnlockIf()
122			* does not call Lock() by itself.
123			*/
124			int PreLockedWaitAndUnlockIf(bool bCondition, long TimeoutSeconds = 0L, long TimeoutNanoSeconds = 0L);
125
126			/**
127	schoenebeck	53	* Set Condition object to \a bCondition. Upon change of the
128			* condition, other threads waiting for \a bCondition will be
129	schoenebeck	63	* awakened. (Note the condition will not be locked for the calling
130			* thread after this method returns!)
131	schoenebeck	53	*
132			* @param bCondition - new condition
133			*/
134			void Set(bool bCondition);
135
136	schoenebeck	1221	/**
137	schoenebeck	3290	* You should use this method instead of Set() in case the calling
138			* thread already owns the Condition object's underlying mutex lock by
139			* previously calling Lock() before. Essentially the only difference to
140			* Set() is that PreLockedSet() does not call Lock() by itself.
141			*/
142			void PreLockedSet(bool bCondition);
143
144			/**
145	schoenebeck	1319	* Returns the current boolean state of this condition object. This
146			* method never blocks, it returns immediately and doesn't use any
147			* system calls.
148			*
149	schoenebeck	1231	* @e Caution: this method is not thread safe! If you need to use
150			* the condition state in a thread critical context you must call
151			* @c Lock() and @c Unlock() respectively by yourself!
152			*/
153	schoenebeck	1221	bool GetUnsafe();
154
155	persson	2316	#ifdef WIN32
156			/**
157			* Resets the condition. This is only needed on Windows, after
158			* a thread waiting for a condition has been stopped with
159			* StopThread.
160			*/
161			void Reset();
162			#endif
163
164	schoenebeck	53	protected:
165	schoenebeck	3290	int WaitIfInternal(bool bLock, bool bCondition, long TimeoutSeconds, long TimeoutNanoSeconds);
166			void SetInternal(bool bLock, bool bCondition);
167
168	senoner	1481	#if defined(WIN32)
169	schoenebeck	1560	friend class ConditionInternal;
170			struct win32thread_cond_t {
171			int waiters_count_; ///< Number of waiting threads.
172			CRITICAL_SECTION waiters_count_lock_; ///< Serialize access to <waiters_count_>.
173			HANDLE sema_; ///< Semaphore used to queue up threads waiting for the condition to become signaled.
174			HANDLE waiters_done_; ///< An auto-reset event used by the broadcast/signal thread to wait for all the waiting thread(s) to wake up and be released from the semaphore.
175			size_t was_broadcast_; ///< Keeps track of whether we were broadcasting or signaling. This allows us to optimize the code if we're just signaling.
176			} __win32_true_condition, __win32_false_condition;
177	senoner	1481	#else
178	schoenebeck	53	pthread_cond_t __posix_true_condition;
179			pthread_cond_t __posix_false_condition;
180	senoner	1481	#endif
181	schoenebeck	53	bool bCondition;
182			};
183
184	schoenebeck	880	} // namespace LinuxSampler
185
186	schoenebeck	53	#endif // __CONDITION_H__