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/*
* thread.h: A simple thread base class
*
* See the main source file 'vdr.c' for copyright information and
* how to reach the author.
*
* $Id: thread.h 2.1 2009/04/13 13:50:39 kls Exp $
*/
#ifndef __THREAD_H
#define __THREAD_H
#include <pthread.h>
#include <stdio.h>
#include <sys/types.h>
class cCondWait {
private:
pthread_mutex_t mutex;
pthread_cond_t cond;
bool signaled;
public:
cCondWait(void);
~cCondWait();
static void SleepMs(int TimeoutMs);
///< Creates a cCondWait object and uses it to sleep for TimeoutMs
///< milliseconds, immediately giving up the calling thread's time
///< slice and thus avoiding a "busy wait".
///< In order to avoid a possible busy wait, TimeoutMs will be automatically
///< limited to values >2.
bool Wait(int TimeoutMs = 0);
///< Waits at most TimeoutMs milliseconds for a call to Signal(), or
///< forever if TimeoutMs is 0.
///< \return Returns true if Signal() has been called, false it the given
///< timeout has expired.
void Signal(void);
///< Signals a caller of Wait() that the condition it is waiting for is met.
};
class cMutex;
class cCondVar {
private:
pthread_cond_t cond;
public:
cCondVar(void);
~cCondVar();
void Wait(cMutex &Mutex);
bool TimedWait(cMutex &Mutex, int TimeoutMs);
void Broadcast(void);
};
class cRwLock {
private:
pthread_rwlock_t rwlock;
public:
cRwLock(bool PreferWriter = false);
~cRwLock();
bool Lock(bool Write, int TimeoutMs = 0);
void Unlock(void);
};
class cMutex {
friend class cCondVar;
private:
pthread_mutex_t mutex;
int locked;
public:
cMutex(void);
~cMutex();
void Lock(void);
void Unlock(void);
};
typedef pid_t tThreadId;
class cThread {
friend class cThreadLock;
private:
bool active;
bool running;
pthread_t childTid;
tThreadId childThreadId;
cMutex mutex;
char *description;
static tThreadId mainThreadId;
static void *StartThread(cThread *Thread);
protected:
void SetPriority(int Priority);
void SetIOPriority(int Priority);
void Lock(void) { mutex.Lock(); }
void Unlock(void) { mutex.Unlock(); }
virtual void Action(void) = 0;
///< A derived cThread class must implement the code it wants to
///< execute as a separate thread in this function. If this is
///< a loop, it must check Running() repeatedly to see whether
///< it's time to stop.
bool Running(void) { return running; }
///< Returns false if a derived cThread object shall leave its Action()
///< function.
void Cancel(int WaitSeconds = 0);
///< Cancels the thread by first setting 'running' to false, so that
///< the Action() loop can finish in an orderly fashion and then waiting
///< up to WaitSeconds seconds for the thread to actually end. If the
///< thread doesn't end by itself, it is killed.
///< If WaitSeconds is -1, only 'running' is set to false and Cancel()
///< returns immediately, without killing the thread.
public:
cThread(const char *Description = NULL);
///< Creates a new thread.
///< If Description is present, a log file entry will be made when
///< the thread starts and stops. The Start() function must be called
///< to actually start the thread.
virtual ~cThread();
void SetDescription(const char *Description, ...) __attribute__ ((format (printf, 2, 3)));
bool Start(void);
///< Actually starts the thread.
///< If the thread is already running, nothing happens.
bool Active(void);
///< Checks whether the thread is still alive.
static tThreadId ThreadId(void);
static tThreadId IsMainThread(void) { return ThreadId() == mainThreadId; }
static void SetMainThreadId(void);
};
// cMutexLock can be used to easily set a lock on mutex and make absolutely
// sure that it will be unlocked when the block will be left. Several locks can
// be stacked, so a function that makes many calls to another function which uses
// cMutexLock may itself use a cMutexLock to make one longer lock instead of many
// short ones.
class cMutexLock {
private:
cMutex *mutex;
bool locked;
public:
cMutexLock(cMutex *Mutex = NULL);
~cMutexLock();
bool Lock(cMutex *Mutex);
};
// cThreadLock can be used to easily set a lock in a thread and make absolutely
// sure that it will be unlocked when the block will be left. Several locks can
// be stacked, so a function that makes many calls to another function which uses
// cThreadLock may itself use a cThreadLock to make one longer lock instead of many
// short ones.
class cThreadLock {
private:
cThread *thread;
bool locked;
public:
cThreadLock(cThread *Thread = NULL);
~cThreadLock();
bool Lock(cThread *Thread);
};
#define LOCK_THREAD cThreadLock ThreadLock(this)
// cPipe implements a pipe that closes all unnecessary file descriptors in
// the child process.
class cPipe {
private:
pid_t pid;
FILE *f;
public:
cPipe(void);
~cPipe();
operator FILE* () { return f; }
bool Open(const char *Command, const char *Mode);
int Close(void);
};
// SystemExec() implements a 'system()' call that closes all unnecessary file
// descriptors in the child process.
// With Detached=true, calls command in background and in a separate session,
// with stdin connected to /dev/null.
int SystemExec(const char *Command, bool Detached = false);
#endif //__THREAD_H