Function searchTokensOnInjector

packages/core/src/render3/di.ts:627–673

(
  injectorIndex: number,
  lView: LView,
  token: ProviderToken<T>,
  previousTView: TView | null,
  flags: InternalInjectFlags,
  hostTElementNode: TNode | null,
)

}

function searchTokensOnInjector<T>(
  injectorIndex: number,
  lView: LView,
  token: ProviderToken<T>,
  previousTView: TView | null,
  flags: InternalInjectFlags,
  hostTElementNode: TNode | null,
) {
  const currentTView = lView[TVIEW];
  const tNode = currentTView.data[injectorIndex + NodeInjectorOffset.TNODE] as TNode;
  // First, we need to determine if view providers can be accessed by the starting element.
  // There are two possibilities
  const canAccessViewProviders =
    previousTView == null
      ? // 1) This is the first invocation `previousTView == null` which means that we are at the
        // `TNode` of where injector is starting to look. In such a case the only time we are allowed
        // to look into the ViewProviders is if:
        // - we are on a component
        // - AND the injector set `includeViewProviders` to true (implying that the token can see
        // ViewProviders because it is the Component or a Service which itself was declared in
        // ViewProviders)
        isComponentHost(tNode) && includeViewProviders
      : // 2) `previousTView != null` which means that we are now walking across the parent nodes.
        // In such a case we are only allowed to look into the ViewProviders if:
        // - We just crossed from child View to Parent View `previousTView != currentTView`
        // - AND the parent TNode is an Element.
        // This means that we just came from the Component's View and therefore are allowed to see
        // into the ViewProviders.
        previousTView != currentTView && (tNode.type & TNodeType.AnyRNode) !== 0;

  // This special case happens when there is a @host on the inject and when we are searching
  // on the host element node.
  const isHostSpecialCase = flags & InternalInjectFlags.Host && hostTElementNode === tNode;

  const injectableIdx = locateDirectiveOrProvider(
    tNode,
    currentTView,
    token,
    canAccessViewProviders,
    isHostSpecialCase,
  );
  if (injectableIdx !== null) {
    return getNodeInjectable(lView, currentTView, injectableIdx, tNode as TElementNode, flags);
  } else {
    return NOT_FOUND;
  }
}

/**
 * Searches for the given token among the node's directives and providers.