//#OPTIONS: CPP

// weak reference support

var h$weakPointerList = [];

#ifdef GHCJS_TRACE_WEAK
function h$traceWeak() { h$log.apply(h$log, arguments) }
#define TRACE_WEAK(args...) h$traceWeak(args)
#else
#define TRACE_WEAK(args...)
#endif

// called by the GC after marking the heap
function h$finalizeWeaks(toFinalize) {
    var mark = h$gcMark;
    var i, w;

    TRACE_WEAK("to finalize: " + toFinalize.length)
    // start a finalizer thread if any finalizers need to be run
    if(toFinalize.length > 0) {
        var t = new h$Thread();
        for(i=0;i<toFinalize.length;i++) {
            w = toFinalize[i];
            t.sp += 6;
            t.stack[t.sp-5] = 0;      // mask
            t.stack[t.sp-4] = h$noop; // handler, dummy
            t.stack[t.sp-3] = h$catch_e;
            t.stack[t.sp-2] = h$ap_1_0;
            t.stack[t.sp-1] = w.finalizer;
            t.stack[t.sp]   = h$return;
            w.finalizer = null;
        }
        h$wakeupThread(t);
    }
}

var h$weakN = 0;
/** @constructor */
function h$Weak(key, val, finalizer) {
    if(typeof key !== 'object') {
        // can't attach a StableName to objects with unboxed storage
        // our weak ref will be finalized soon.
        TRACE_WEAK("WARNING: making weak for object with unboxed storage")
        this.keym = new h$StableName(0);
    } else {
        if(typeof key.m !== 'object') {
          if(typeof key.m !== 'number') {
            h$log("attaching weak to unsupported object");
          }
          key.m = new h$StableName(key.m);
        }
        this.keym = key.m;
    }
    TRACE_WEAK("making weak of: " + h$stableNameInt(this.keym))
    this.keym      = key.m;
    this.val       = val;
    this.finalizer = null;
    if(finalizer !== null) {
        this.finalizer = finalizer;
    }
    this.m = 0;
    this._key = ++h$weakN;
    h$weakPointerList.push(this);
#ifdef GHCJS_DEBUG_ALLOC
    h$debugAlloc_notifyAlloc(this);
#endif
}

function h$makeWeak(key, val, fin) {
    TRACE_WEAK("h$makeWeak")
    return new h$Weak(key, val, fin)
}

function h$makeWeakNoFinalizer(key, val) {
    TRACE_WEAK("h$makeWeakNoFinalizer")
    return new h$Weak(key, val, null);
}

function h$finalizeWeak(w) {
    TRACE_WEAK("finalizing weak of " + h$stableNameInt(w.keym))
    w.val  = null;
    if(w.finalizer === null || w.finalizer.finalizer === null) {
        RETURN_UBX_TUP2(null, 0);
    } else {
        var r = w.finalizer;
        w.finalizer = null;
        RETURN_UBX_TUP2(r, 1);
    }
}