src/common/Condition.h

/***************************************************************************
 *                                                                         *
 *   LinuxSampler - modular, streaming capable sampler                     *
 *                                                                         *
 *   Copyright (C) 2003, 2004 by Benno Senoner and Christian Schoenebeck   *
 *   Copyright (C) 2005 - 2007 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:
        /**
         * Constructor
         *
         * @param bInitialCondition - optional: starting condition
         *                            (default = false)
         */
        Condition(bool bInitialCondition = false);

        /**
         * 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);

        /**
         * 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);

        /**
         * 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();

    protected:
    #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	1221	* Copyright (C) 2005 - 2007 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			/**
47			* Constructor
48			*
49			* @param bInitialCondition - optional: starting condition
50			* (default = false)
51			*/
52			Condition(bool bInitialCondition = false);
53
54			/**
55			* Destructor
56			*/
57	letz	502	virtual ~Condition();
58	schoenebeck	53
59			/**
60			* Blocks the calling thread if current condition equals
61			* \a bCondition, in this case the calling thread will be blocked
62			* until condition turns. Upon successful return the Condition
63			* object is locked, so the calling thread can safely run it's
64			* critical section and has to explicitly call Unlock() right after
65			* it left it's critcal section.
66			*
67	schoenebeck	1221	* @e Note: If you don't provide a timeout value or if you provide a
68			* timeout value of exactly 0s and 0ns, then this call will block
69	schoenebeck	1319	* without any timeout, or in other words: @e infinity!
70	schoenebeck	1221	*
71	schoenebeck	53	* @param bCondition - block in case of this condition
72			* @param TimeoutSeconds - optional: max. wait time in seconds
73			* (default: 0s)
74			* @param TimeoutNanoSeconds - optional: max wait time in nano
75			* seconds (default: 0ns)
76			* @returns 0 on success, a value less than 0 if timeout exceeded
77			*/
78			int WaitIf(bool bCondition, long TimeoutSeconds = 0L, long TimeoutNanoSeconds = 0L);
79
80			/**
81			* Same as WaitIf(), except that WaitAndUnlockIf() will unlock the
82			* Condition object, so only use this call if you don't need to
83			* enter a thread critical section, otherwise use WaitIf() instead!
84			*
85	schoenebeck	1221	* @e Note: If you don't provide a timeout value or if you provide a
86			* timeout value of exactly 0s and 0ns, then this call will block
87	schoenebeck	1319	* without any timeout, or in other words: @e infinity!
88	schoenebeck	1221	*
89	schoenebeck	53	* @param bCondition - block in case of this condition
90			* @param TimeoutSeconds - optional: max. wait time in seconds
91			* (default: 0s)
92			* @param TimeoutNanoSeconds - optional: max wait time in nano
93			* seconds (default: 0ns)
94			* @returns 0 on success, a value less than 0 if timeout exceeded
95			* @see WaitIf()
96			*/
97			int WaitAndUnlockIf(bool bCondition, long TimeoutSeconds = 0L, long TimeoutNanoSeconds = 0L);
98
99			/**
100			* Set Condition object to \a bCondition. Upon change of the
101			* condition, other threads waiting for \a bCondition will be
102	schoenebeck	63	* awakened. (Note the condition will not be locked for the calling
103			* thread after this method returns!)
104	schoenebeck	53	*
105			* @param bCondition - new condition
106			*/
107			void Set(bool bCondition);
108
109	schoenebeck	1221	/**
110	schoenebeck	1319	* Returns the current boolean state of this condition object. This
111			* method never blocks, it returns immediately and doesn't use any
112			* system calls.
113			*
114	schoenebeck	1231	* @e Caution: this method is not thread safe! If you need to use
115			* the condition state in a thread critical context you must call
116			* @c Lock() and @c Unlock() respectively by yourself!
117			*/
118	schoenebeck	1221	bool GetUnsafe();
119
120	schoenebeck	53	protected:
121	senoner	1481	#if defined(WIN32)
122	schoenebeck	1560	friend class ConditionInternal;
123			struct win32thread_cond_t {
124			int waiters_count_; ///< Number of waiting threads.
125			CRITICAL_SECTION waiters_count_lock_; ///< Serialize access to <waiters_count_>.
126			HANDLE sema_; ///< Semaphore used to queue up threads waiting for the condition to become signaled.
127			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.
128			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.
129			} __win32_true_condition, __win32_false_condition;
130	senoner	1481	#else
131	schoenebeck	53	pthread_cond_t __posix_true_condition;
132			pthread_cond_t __posix_false_condition;
133	senoner	1481	#endif
134	schoenebeck	53	bool bCondition;
135			};
136
137	schoenebeck	880	} // namespace LinuxSampler
138
139	schoenebeck	53	#endif // __CONDITION_H__