Function getParentInjectorLocation

packages/core/src/render3/di.ts:258–296

(tNode: TNode, lView: LView)

 * to find the LView containing the parent inject AND the index of the injector within that LView.
 */
export function getParentInjectorLocation(tNode: TNode, lView: LView): RelativeInjectorLocation {
  if (tNode.parent && tNode.parent.injectorIndex !== -1) {
    // If we have a parent `TNode` and there is an injector associated with it we are done, because
    // the parent injector is within the current `LView`.
    return tNode.parent.injectorIndex as RelativeInjectorLocation; // ViewOffset is 0
  }

  // When parent injector location is computed it may be outside of the current view. (ie it could
  // be pointing to a declared parent location). This variable stores number of declaration parents
  // we need to walk up in order to find the parent injector location.
  let declarationViewOffset = 0;
  let parentTNode: TNode | null = null;
  let lViewCursor: LView | null = lView;

  // The parent injector is not in the current `LView`. We will have to walk the declared parent
  // `LView` hierarchy and look for it. If we walk of the top, that means that there is no parent
  // `NodeInjector`.
  while (lViewCursor !== null) {
    parentTNode = getTNodeFromLView(lViewCursor);

    if (parentTNode === null) {
      // If we have no parent, than we are done.
      return NO_PARENT_INJECTOR;
    }

    ngDevMode && parentTNode && assertTNodeForLView(parentTNode!, lViewCursor[DECLARATION_VIEW]!);
    // Every iteration of the loop requires that we go to the declared parent.
    declarationViewOffset++;
    lViewCursor = lViewCursor[DECLARATION_VIEW];

    if (parentTNode.injectorIndex !== -1) {
      // We found a NodeInjector which points to something.
      return (parentTNode.injectorIndex |
        (declarationViewOffset <<
          RelativeInjectorLocationFlags.ViewOffsetShift)) as RelativeInjectorLocation;
    }
  }
  return NO_PARENT_INJECTOR;
}
/**
 * Makes a type or an injection token public to the DI system by adding it to an
 * injector's bloom filter.