C++ FocusCandidate::document方法代码示例

static void updateFocusCandidateIfCloser(Node* focusedNode, const FocusCandidate& candidate, FocusCandidate& closest)
{
    // First, check the common case: neither candidate nor closest are
    // inside scrollable content, then no need to care about enclosingScrollableBox
    // heuristics or parent{Distance,Alignment}, but only distance and alignment.
    if (!candidate.inScrollableContainer() && !closest.inScrollableContainer()) {
        updateFocusCandidateInSameContainer(candidate, closest);
        return;
    }

    bool sameContainer = candidate.document() == closest.document() && candidate.enclosingScrollableBox == closest.enclosingScrollableBox;

    // Second, if candidate and closest are in the same "container" (i.e. {i}frame or any
    // scrollable block element), we can handle them as common case.
    if (sameContainer) {
        updateFocusCandidateInSameContainer(candidate, closest);
        return;
    }

    // Last, we are considering moving to a candidate located in a different enclosing
    // scrollable box than closest.
    bool isInInnerDocument = !isInRootDocument(focusedNode);

    bool sameContainerAsCandidate = isInInnerDocument ? focusedNode->document() == candidate.document() :
        focusedNode->isDescendantOf(candidate.enclosingScrollableBox);

    bool sameContainerAsClosest = isInInnerDocument ? focusedNode->document() == closest.document() :
        focusedNode->isDescendantOf(closest.enclosingScrollableBox);

    // sameContainerAsCandidate and sameContainerAsClosest are mutually exclusive.
    ASSERT(!(sameContainerAsCandidate && sameContainerAsClosest));

    if (sameContainerAsCandidate) {
        closest = candidate;
        return;
    }

    if (sameContainerAsClosest) {
        // Nothing to be done.
        return;
    }

    // NOTE: !sameContainerAsCandidate && !sameContainerAsClosest
    // If distance is shorter, and we are talking about scrollable container,
    // lets compare parent distance and alignment before anything.
    if (candidate.distance < closest.distance) {
        if (candidate.alignment >= closest.parentAlignment
         || candidate.parentAlignment == closest.parentAlignment) {
            closest = candidate;
            return;
        }

    } else if (candidate.parentDistance < closest.distance) {
        if (candidate.parentAlignment >= closest.alignment) {
            closest = candidate;
            return;
        }
    }
}

// FIXME: Make this method more modular, and simpler to understand and maintain.
static void updateFocusCandidateIfCloser(Node* focusedNode, const FocusCandidate& candidate, FocusCandidate& closest)
{
    bool sameDocument = candidate.document() == closest.document();
    if (sameDocument) {
        if (closest.alignment > candidate.alignment
         || (closest.parentAlignment && candidate.alignment > closest.parentAlignment))
            return;
    } else if (closest.alignment > candidate.alignment
            && (closest.parentAlignment && candidate.alignment > closest.parentAlignment))
        return;

    if (candidate.alignment != None
     || (closest.parentAlignment >= candidate.alignment
     && closest.document() == candidate.document())) {

        // If we are now in an higher precedent case, lets reset the current closest's
        // distance so we force it to be bigger than any result we will get from
        // spatialDistance().
        if (closest.alignment < candidate.alignment
         && closest.parentAlignment < candidate.alignment)
            closest.distance = maxDistance();
    }

    // Bail out if candidate's distance is larger than that of the closest candidate.
    if (candidate.distance >= closest.distance)
        return;

    if (closest.isNull()) {
        closest = candidate;
        return;
    }

    // If the focused node and the candadate are in the same document and current
    // closest candidate is not in an {i}frame that is preferable to get focused ...
    if (focusedNode->document() == candidate.document()
        && candidate.distance < closest.parentDistance)
        closest = candidate;
    else if (focusedNode->document() != candidate.document()) {
        // If the focusedNode is in an inner document and candidate is in a
        // different document, we only consider to change focus if there is not
        // another already good focusable candidate in the same document as focusedNode.
        if (!((isInRootDocument(candidate.node) && !isInRootDocument(focusedNode))
            && focusedNode->document() == closest.document()))
            closest = candidate;
    }
}