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tlib/oversampling/WDL/destroycheck.h
2024-05-24 13:28:31 +02:00

66 lines
1.6 KiB
C++

#ifndef _WDL_DESTROYCHECK_H_
#define _WDL_DESTROYCHECK_H_
// this is a useful class for verifying that an object (usually "this") hasn't been destroyed:
// to use it you add a WDL_DestroyState as a member of your class, then use the WDL_DestroyCheck
// helper class (creating it when the pointer is known valid, and checking it later to see if it
// is still valid).
//
// example:
// class myClass {
// WDL_DestroyState dest;
// ...
// };
//
// calling code (on myClass *classInstnace):
// WDL_DestroyCheck chk(&classInstance->dest);
// somefunction();
// if (!chk.isOK()) printf("classInstance got deleted!\n");
//
// NOTE: only use this when these objects will be accessed from the same thread -- it will fail miserably
// in a multithreaded environment
class WDL_DestroyCheck
{
public:
class WDL_DestroyStateNextRec { public: WDL_DestroyCheck *next; };
WDL_DestroyStateNextRec n, *prev;
WDL_DestroyCheck(WDL_DestroyStateNextRec *state)
{
n.next=NULL;
if ((prev=state))
{
if ((n.next=prev->next)) n.next->prev = &n;
prev->next=this;
}
}
~WDL_DestroyCheck()
{
if (prev)
{
prev->next = n.next;
if (n.next) n.next->prev = prev;
}
}
bool isOK() { return !!prev; }
};
class WDL_DestroyState : public WDL_DestroyCheck::WDL_DestroyStateNextRec
{
public:
WDL_DestroyState() { next=NULL; }
~WDL_DestroyState()
{
WDL_DestroyCheck *p = next;
while (p) { WDL_DestroyCheck *np = p->n.next; p->prev=NULL; p->n.next=NULL; p=np; }
}
};
#endif