Files
epics-base/modules/libcom/src/osi/epicsThread.cpp
2020-04-15 21:39:54 -05:00

394 lines
11 KiB
C++

/*************************************************************************\
* Copyright (c) 2008 UChicago Argonne LLC, as Operator of Argonne
* National Laboratory.
* Copyright (c) 2002 The Regents of the University of California, as
* Operator of Los Alamos National Laboratory.
* EPICS BASE is distributed subject to a Software License Agreement found
* in file LICENSE that is included with this distribution.
\*************************************************************************/
//
// Author: Jeff Hill
//
#include <exception>
#include <typeinfo>
#include <stdio.h>
#include <stddef.h>
#include <float.h>
#include <string.h>
// The following is required for Solaris builds
#undef __EXTENSIONS__
#define epicsExportSharedSymbols
#include "epicsAlgorithm.h"
#include "epicsTime.h"
#include "epicsThread.h"
#include "epicsAssert.h"
#include "epicsGuard.h"
#include "errlog.h"
using namespace std;
epicsThreadId epicsShareAPI epicsThreadCreate (
const char * name, unsigned int priority, unsigned int stackSize,
EPICSTHREADFUNC funptr,void * parm )
{
epicsThreadOpts opts = EPICS_THREAD_OPTS_INIT;
opts.priority = priority;
opts.stackSize = stackSize;
opts.joinable = 0;
return epicsThreadCreateOpt(name, funptr, parm, &opts);
}
epicsThreadRunable::~epicsThreadRunable () {}
void epicsThreadRunable::run () {}
void epicsThreadRunable::show ( unsigned int ) const {}
class epicsThread :: unableToCreateThread :
public std :: exception {
public:
const char * what () const throw ();
};
const char * epicsThread ::
unableToCreateThread :: what () const throw ()
{
return "unable to create thread";
}
void epicsThread :: printLastChanceExceptionMessage (
const char * pExceptionTypeName,
const char * pExceptionContext )
{
char date[64];
try {
epicsTime cur = epicsTime :: getCurrent ();
cur.strftime ( date, sizeof ( date ), "%a %b %d %Y %H:%M:%S.%f");
}
catch ( ... ) {
strcpy ( date, "<UKN DATE>" );
}
char name [128];
epicsThreadGetName ( this->id, name, sizeof ( name ) );
errlogPrintf (
"epicsThread: Unexpected C++ exception \"%s\" "
"with type \"%s\" in thread \"%s\" at %s\n",
pExceptionContext, pExceptionTypeName, name, date );
errlogFlush ();
// This behavior matches the C++ implementation when an exception
// isn't handled by the thread code. Users can install their own
// application-specific unexpected handler if preferred.
std::unexpected ();
}
extern "C" void epicsThreadCallEntryPoint ( void * pPvt )
{
epicsThread * pThread =
static_cast <epicsThread *> ( pPvt );
bool threadDestroyed = false;
try {
pThread->pThreadDestroyed = & threadDestroyed;
if ( pThread->beginWait () ) {
pThread->runable.run ();
// The run() routine may have destroyed the epicsThread
// object by now; pThread can only be used below here
// when the threadDestroyed flag is false.
}
}
catch ( const epicsThread::exitException & ) {
}
catch ( std :: exception & except ) {
if ( ! threadDestroyed ) {
pThread->printLastChanceExceptionMessage (
typeid ( except ).name (), except.what () );
}
}
catch ( ... ) {
if ( ! threadDestroyed ) {
pThread->printLastChanceExceptionMessage (
"catch ( ... )", "Non-standard C++ exception" );
}
}
if ( ! threadDestroyed ) {
epicsGuard < epicsMutex > guard ( pThread->mutex );
pThread->pThreadDestroyed = NULL;
pThread->terminated = true;
pThread->exitEvent.signal ();
// After the terminated flag is set and guard's destructor
// releases the lock, pThread must never be used again.
}
}
bool epicsThread::beginWait () throw ()
{
epicsGuard < epicsMutex > guard ( this->mutex );
while ( ! this->begin && ! this->cancel ) {
epicsGuardRelease < epicsMutex > unguard ( guard );
this->event.wait ();
}
return this->begin && ! this->cancel;
}
void epicsThread::exit ()
{
throw exitException ();
}
void epicsThread::exitWait () throw ()
{
bool success = this->exitWait ( DBL_MAX );
assert ( success );
}
bool epicsThread::exitWait ( const double delay ) throw ()
{
try {
// When called (usually by a destructor) in the context of
// the managed thread we can't wait for the thread to exit.
// Set the threadDestroyed flag and return success.
if ( this->isCurrentThread() ) {
if ( this->pThreadDestroyed ) {
*this->pThreadDestroyed = true;
}
bool j;
{
epicsGuard < epicsMutex > guard ( this->mutex );
j = joined;
joined = true;
}
if(!j) {
epicsThreadMustJoin(this->id);
}
return true;
}
epicsTime exitWaitBegin = epicsTime::getMonotonic ();
double exitWaitElapsed = 0.0;
epicsGuard < epicsMutex > guard ( this->mutex );
this->cancel = true;
while ( ! this->terminated && exitWaitElapsed < delay ) {
epicsGuardRelease < epicsMutex > unguard ( guard );
this->event.signal ();
this->exitEvent.wait ( delay - exitWaitElapsed );
epicsTime current = epicsTime::getMonotonic ();
exitWaitElapsed = current - exitWaitBegin;
}
if(this->terminated && !joined) {
joined = true;
epicsGuardRelease < epicsMutex > unguard ( guard );
epicsThreadMustJoin(this->id);
}
}
catch ( std :: exception & except ) {
errlogPrintf (
"epicsThread::exitWait(): Unexpected exception "
" \"%s\"\n",
except.what () );
epicsThreadSleep ( epicsMin ( delay, 5.0 ) );
}
catch ( ... ) {
errlogPrintf (
"Non-standard unexpected exception in "
"epicsThread::exitWait()\n" );
epicsThreadSleep ( epicsMin ( delay, 5.0 ) );
}
// the event mechanism is used for other purposes
this->event.signal ();
return this->terminated;
}
epicsThread::epicsThread (
epicsThreadRunable & runableIn, const char * pName,
unsigned stackSize, unsigned priority ) :
runable ( runableIn ), id ( 0 ), pThreadDestroyed ( 0 ),
begin ( false ), cancel ( false ), terminated ( false ),
joined ( false )
{
epicsThreadOpts opts = EPICS_THREAD_OPTS_INIT;
opts.stackSize = stackSize;
opts.priority = priority;
opts.joinable = 1;
this->id = epicsThreadCreateOpt(
pName, epicsThreadCallEntryPoint,
static_cast < void * > ( this ),
&opts);
if ( ! this->id ) {
throw unableToCreateThread ();
}
}
epicsThread::~epicsThread () throw ()
{
while ( ! this->exitWait ( 10.0 ) ) {
char nameBuf [256];
this->getName ( nameBuf, sizeof ( nameBuf ) );
fprintf ( stderr,
"epicsThread::~epicsThread(): \"%s\" blocking for thread \"%s\" to exit\n",
getNameSelf(), nameBuf );
fprintf ( stderr,
"was epicsThread object destroyed before thread exit ?\n");
}
}
void epicsThread::start () throw ()
{
{
epicsGuard < epicsMutex > guard ( this->mutex );
this->begin = true;
}
this->event.signal ();
}
bool epicsThread::isCurrentThread () const throw ()
{
return ( epicsThreadGetIdSelf () == this->id );
}
void epicsThread::resume () throw ()
{
epicsThreadResume ( this->id );
}
void epicsThread::getName ( char *name, size_t size ) const throw ()
{
epicsThreadGetName ( this->id, name, size );
}
epicsThreadId epicsThread::getId () const throw ()
{
return this->id;
}
unsigned int epicsThread::getPriority () const throw ()
{
return epicsThreadGetPriority (this->id);
}
void epicsThread::setPriority (unsigned int priority) throw ()
{
epicsThreadSetPriority (this->id, priority);
}
bool epicsThread::priorityIsEqual (const epicsThread &otherThread) const throw ()
{
if ( epicsThreadIsEqual (this->id, otherThread.id) ) {
return true;
}
return false;
}
bool epicsThread::isSuspended () const throw ()
{
if ( epicsThreadIsSuspended (this->id) ) {
return true;
}
return false;
}
bool epicsThread::operator == (const epicsThread &rhs) const throw ()
{
return (this->id == rhs.id);
}
void epicsThread::suspendSelf () throw ()
{
epicsThreadSuspendSelf ();
}
void epicsThread::sleep (double seconds) throw ()
{
epicsThreadSleep (seconds);
}
const char *epicsThread::getNameSelf () throw ()
{
return epicsThreadGetNameSelf ();
}
bool epicsThread::isOkToBlock () throw ()
{
return epicsThreadIsOkToBlock() != 0;
}
void epicsThread::setOkToBlock(bool isOkToBlock) throw ()
{
epicsThreadSetOkToBlock(static_cast<int>(isOkToBlock));
}
void epicsThreadPrivateBase::throwUnableToCreateThreadPrivate ()
{
throw epicsThreadPrivateBase::unableToCreateThreadPrivate ();
}
void epicsThread :: show ( unsigned level ) const throw ()
{
::printf ( "epicsThread at %p\n", this->id );
if ( level > 0u ) {
epicsThreadShow ( this->id, level - 1 );
if ( level > 1u ) {
::printf ( "pThreadDestroyed = %p\n", this->pThreadDestroyed );
::printf ( "begin = %c, cancel = %c, terminated = %c\n",
this->begin ? 'T' : 'F',
this->cancel ? 'T' : 'F',
this->terminated ? 'T' : 'F' );
this->runable.show ( level - 2u );
this->mutex.show ( level - 2u );
::printf ( "general purpose event\n" );
this->event.show ( level - 2u );
::printf ( "exit event\n" );
this->exitEvent.show ( level - 2u );
}
}
}
extern "C" {
static epicsThreadOnceId okToBlockOnce = EPICS_THREAD_ONCE_INIT;
epicsThreadPrivateId okToBlockPrivate;
static const int okToBlockNo = 0;
static const int okToBlockYes = 1;
static void epicsThreadOnceIdInit(void *)
{
okToBlockPrivate = epicsThreadPrivateCreate();
}
int epicsShareAPI epicsThreadIsOkToBlock(void)
{
const int *pokToBlock;
epicsThreadOnce(&okToBlockOnce, epicsThreadOnceIdInit, NULL);
pokToBlock = (int *) epicsThreadPrivateGet(okToBlockPrivate);
return (pokToBlock ? *pokToBlock : 0);
}
void epicsShareAPI epicsThreadSetOkToBlock(int isOkToBlock)
{
const int *pokToBlock;
epicsThreadOnce(&okToBlockOnce, epicsThreadOnceIdInit, NULL);
pokToBlock = (isOkToBlock) ? &okToBlockYes : &okToBlockNo;
epicsThreadPrivateSet(okToBlockPrivate, (void *)pokToBlock);
}
epicsThreadId epicsShareAPI epicsThreadMustCreate (
const char *name, unsigned int priority, unsigned int stackSize,
EPICSTHREADFUNC funptr,void *parm)
{
epicsThreadId id = epicsThreadCreate (
name, priority, stackSize, funptr, parm );
assert ( id );
return id;
}
} // extern "C"
static epicsThreadId initMainThread(void) {
epicsThreadId main = epicsThreadGetIdSelf();
epicsThreadSetOkToBlock(1);
return main;
}
// Ensure the main thread gets a unique ID and allows blocking I/O
epicsThreadId epicsThreadMainId = initMainThread();