public void unregisterOnCancel()

in sdk/core/azure-core/src/main/java/com/azure/android/core/util/CancellationToken.java [129:197]
49 lines of code
14 McCabe index (conditional complexity)

    public void unregisterOnCancel(String id) {
        if (this == CancellationToken.NONE) {
            return;
        }
        OnCancelNode itr = this.onCancelNodes;
        // Step_1: Locate the node and mark it as logically deleted.
        //
        while (itr != null) {
            if (this.onCancelNodes == OnCancelNode.FROZEN) {
                // The token is cancelled, no use in progressing.
                return;
            }
            if (itr.id != null && itr.id.equals(id)) {
                // Mark the node as logically deleted.
                itr.markDeleted();
                break;
            }
            itr = itr.next;
        }
        if (itr == null) {
            // A node with id was not found.
            return;
        }

        // Step_2: Sweep to unlink all logically deleted nodes.
        //
        boolean hadRace;
        do {
            // Outer 'do-while' to retry on any race during sweep.
            hadRace = false;
            OnCancelNode predecessor = null;
            OnCancelNode current = this.onCancelNodes; // re-fetch the volatile head for each retry.
            if (current == OnCancelNode.FROZEN) {
                // The token is cancelled, no use in sweeping.
                return;
            }
            OnCancelNode successor;
            // Inner 'while' to sweep & unlink all logically deleted nodes.
            while (current != null) {
                successor = current.next;
                if (current.isDeleted()) {
                    // Un-linking 'current' node.
                    if (predecessor == null) {
                        // The 'current' node has no 'predecessor' hence it's head, try CAS head with 'successor'.
                        if (!ON_CANCEL_NODES_UPDATER.compareAndSet(this, current, successor)) {
                            // Raced with
                            //     1. another thread calling registerOnCancelCallback.
                            //     2. OR the 'cancel()' call.
                            // need to retry.
                            hadRace = true;
                            break;
                        }
                    } else {
                        // The 'current' node has a 'predecessor'.
                        predecessor.next = successor;
                        if (predecessor.isDeleted()) {
                            // Raced with another thread that unlinked 'predecessor', need to retry.
                            hadRace = true;
                            break;
                        }
                    }
                } else {
                    // We aren't un-linking 'current' node, update 'predecessor'.
                    predecessor = current;
                }
                current = successor;
            }
        } while (hadRace);
    }