#include "StHandleUnlocker.h"
#include "CThrownResult.h"

// ===========================================================================
//	¥ StHandleUnlocker Class
// ===========================================================================
//	Constructor Locks the Handle
//	Destructor restores the Handle's original locked/unlocked state

StHandleUnlocker::StHandleUnlocker(
	Handle	inHandle)
{
	mHandle		 = nil;
	mWasLocked = false;

	Adopt(inHandle);
}


StHandleUnlocker::~StHandleUnlocker()
{
	RestoreLockState();
}


void
StHandleUnlocker::RestoreLockState()
{
	if (mWasLocked && (mHandle != nil)) {
		::HLock(mHandle);
	}
}


void
StHandleUnlocker::Adopt(				// Take control over locking
	Handle	inHandle)				//   and unlocking this Handle
{
	RestoreLockState();				// Restore state of current Handle
		
	mHandle		 = inHandle;		// Store new Handle
	mWasLocked = false;
	
	if (inHandle != nil) {			// Lock new Handle
	
		SInt8	theState = ::HGetState(inHandle);
		CThrownOSErr err = ::MemError();
	
			// Bit 7 of state is set if Handle is locked. We want to
			// know if the Handle is currently locked or unlocked.
			// If it is locked, we unlock it now and lock it the
			// destructor. If it is already un locked, we do nothing
			// here and nothing in the destructor.
	
		mWasLocked = (theState & 0x80) != 0;	// Locked if bit 7 is set
	
		if (mWasLocked) {
			::HUnlock(inHandle);
		}
	}
}


Handle								// Relinquish control of Handle
StHandleUnlocker::Release()
{
	RestoreLockState();
	
	Handle	outHandle = mHandle;
	
	mHandle		 = nil;				// We now have no Handle
	mWasLocked = false;
	
	return outHandle;
}