fun rehash()

in kotlinx-coroutines-core/jvm/src/debug/internal/ConcurrentWeakMap.kt [158:188]
29 lines of code
12 McCabe index (conditional complexity)

        fun rehash(): Core {
            // use size to approximate new required capacity to have at least 25-50% fill factor,
            // may fail due to concurrent modification, will retry
            retry@while (true) {
                val newCapacity = size.coerceAtLeast(MIN_CAPACITY / 4).takeHighestOneBit() * 4
                val newCore = Core(newCapacity)
                for (index in 0 until allocated) {
                    // load the key
                    val w = keys[index].value
                    val k = w?.get()
                    if (w != null && k == null) removeCleanedAt(index) // weak ref was here, but collected
                    // mark value so that it cannot be changed while we rehash to new core
                    var value: Any?
                    while (true) {
                        value = values[index].value
                        if (value is Marked) { // already marked -- good
                            value = value.ref
                            break
                        }
                        // try mark
                        if (values[index].compareAndSet(value, value.mark())) break
                    }
                    if (k != null && value != null) {
                        val oldValue = newCore.putImpl(k, value as V, w)
                        if (oldValue === REHASH) continue@retry // retry if we underestimated capacity
                        assert(oldValue == null)
                    }
                }
                return newCore // rehashed everything successfully
            }
        }