haiku/src/kits/support/Referenceable.cpp
2013-10-01 15:47:53 +02:00

106 lines
2.4 KiB
C++

/*
* Copyright 2005-2009, Ingo Weinhold, ingo_weinhold@gmx.de.
* Distributed under the terms of the MIT License.
*/
#include <Referenceable.h>
#ifdef DEBUG
#include <stdio.h>
#endif
#include <OS.h>
//#define TRACE_REFERENCEABLE
#if defined(TRACE_REFERENCEABLE) && defined(_KERNEL_MODE)
# include <tracing.h>
# define TRACE(x, ...) ktrace_printf(x, __VA_ARGS__);
#else
# define TRACE(x, ...)
#endif
BReferenceable::BReferenceable()
:
fReferenceCount(1)
{
}
BReferenceable::~BReferenceable()
{
#if defined(DEBUG) && !defined(_BOOT_MODE)
bool enterDebugger = false;
char message[256];
if (fReferenceCount == 1) {
// Simple heuristic to test if this object was allocated
// on the stack: check if this is within 1KB in either
// direction of the current stack address, and the reference
// count is 1. If so, we don't flag a warning since that would
// imply the object was allocated/destroyed on the stack
// without any references being acquired or released.
char test;
ssize_t testOffset = (addr_t)this - (addr_t)&test;
if (testOffset > 1024 || -testOffset > 1024) {
// might still be a stack object, check the thread's
// stack range to be sure.
thread_info info;
status_t result = get_thread_info(find_thread(NULL), &info);
if (result == B_OK && (this < info.stack_base
|| this > info.stack_end)) {
snprintf(message, sizeof(message), "Deleted referenceable "
"object that's not on the stack (this: %p, stack_base: %p,"
" stack_end: %p)\n", this, info.stack_base,
info.stack_end);
enterDebugger = true;
}
}
} else if (fReferenceCount != 0) {
snprintf(message, sizeof(message), "Deleted referenceable object %p with "
"non-zero reference count (%" B_PRId32 ")\n", this, fReferenceCount);
enterDebugger = true;
}
if (enterDebugger)
debugger(message);
#endif
}
int32
BReferenceable::AcquireReference()
{
int32 previousReferenceCount = atomic_add(&fReferenceCount, 1);
if (previousReferenceCount == 0)
FirstReferenceAcquired();
TRACE("%p: acquire %ld\n", this, fReferenceCount);
return previousReferenceCount;
}
int32
BReferenceable::ReleaseReference()
{
int32 previousReferenceCount = atomic_add(&fReferenceCount, -1);
TRACE("%p: release %ld\n", this, fReferenceCount);
if (previousReferenceCount == 1)
LastReferenceReleased();
return previousReferenceCount;
}
void
BReferenceable::FirstReferenceAcquired()
{
}
void
BReferenceable::LastReferenceReleased()
{
delete this;
}