gecko-dev/dom/base/ChildIterator.cpp

611 строки
18 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
* You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "ChildIterator.h"
#include "nsContentUtils.h"
#include "mozilla/dom/XBLChildrenElement.h"
#include "mozilla/dom/HTMLContentElement.h"
#include "mozilla/dom/HTMLShadowElement.h"
#include "mozilla/dom/ShadowRoot.h"
#include "nsIAnonymousContentCreator.h"
#include "nsIFrame.h"
#include "nsCSSAnonBoxes.h"
namespace mozilla {
namespace dom {
class MatchedNodes {
public:
explicit MatchedNodes(HTMLContentElement* aInsertionPoint)
: mIsContentElement(true), mContentElement(aInsertionPoint) {}
explicit MatchedNodes(XBLChildrenElement* aInsertionPoint)
: mIsContentElement(false), mChildrenElement(aInsertionPoint) {}
uint32_t Length() const
{
return mIsContentElement ? mContentElement->MatchedNodes().Length()
: mChildrenElement->InsertedChildrenLength();
}
nsIContent* operator[](int32_t aIndex) const
{
return mIsContentElement ? mContentElement->MatchedNodes()[aIndex]
: mChildrenElement->InsertedChild(aIndex);
}
bool IsEmpty() const
{
return mIsContentElement ? mContentElement->MatchedNodes().IsEmpty()
: !mChildrenElement->HasInsertedChildren();
}
protected:
bool mIsContentElement;
union {
HTMLContentElement* mContentElement;
XBLChildrenElement* mChildrenElement;
};
};
static inline MatchedNodes
GetMatchedNodesForPoint(nsIContent* aContent)
{
if (aContent->NodeInfo()->Equals(nsGkAtoms::children, kNameSpaceID_XBL)) {
// XBL case
return MatchedNodes(static_cast<XBLChildrenElement*>(aContent));
}
// Web components case
MOZ_ASSERT(aContent->IsHTMLElement(nsGkAtoms::content));
return MatchedNodes(HTMLContentElement::FromContent(aContent));
}
nsIContent*
ExplicitChildIterator::GetNextChild()
{
// If we're already in the inserted-children array, look there first
if (mIndexInInserted) {
MOZ_ASSERT(mChild);
MOZ_ASSERT(nsContentUtils::IsContentInsertionPoint(mChild));
MOZ_ASSERT(!mDefaultChild);
MatchedNodes assignedChildren = GetMatchedNodesForPoint(mChild);
if (mIndexInInserted < assignedChildren.Length()) {
return assignedChildren[mIndexInInserted++];
}
mIndexInInserted = 0;
mChild = mChild->GetNextSibling();
} else if (mShadowIterator) {
// If we're inside of a <shadow> element, look through the
// explicit children of the projected ShadowRoot via
// the mShadowIterator.
nsIContent* nextChild = mShadowIterator->GetNextChild();
if (nextChild) {
return nextChild;
}
mShadowIterator = nullptr;
mChild = mChild->GetNextSibling();
} else if (mDefaultChild) {
// If we're already in default content, check if there are more nodes there
MOZ_ASSERT(mChild);
MOZ_ASSERT(nsContentUtils::IsContentInsertionPoint(mChild));
mDefaultChild = mDefaultChild->GetNextSibling();
if (mDefaultChild) {
return mDefaultChild;
}
mChild = mChild->GetNextSibling();
} else if (mIsFirst) { // at the beginning of the child list
mChild = mParent->GetFirstChild();
mIsFirst = false;
} else if (mChild) { // in the middle of the child list
mChild = mChild->GetNextSibling();
}
// Iterate until we find a non-insertion point, or an insertion point with
// content.
while (mChild) {
// If the current child being iterated is a shadow insertion point then
// the iterator needs to go into the projected ShadowRoot.
if (ShadowRoot::IsShadowInsertionPoint(mChild)) {
// Look for the next child in the projected ShadowRoot for the <shadow>
// element.
HTMLShadowElement* shadowElem = HTMLShadowElement::FromContent(mChild);
ShadowRoot* projectedShadow = shadowElem->GetOlderShadowRoot();
if (projectedShadow) {
mShadowIterator = new ExplicitChildIterator(projectedShadow);
nsIContent* nextChild = mShadowIterator->GetNextChild();
if (nextChild) {
return nextChild;
}
mShadowIterator = nullptr;
}
mChild = mChild->GetNextSibling();
} else if (nsContentUtils::IsContentInsertionPoint(mChild)) {
// If the current child being iterated is a content insertion point
// then the iterator needs to return the nodes distributed into
// the content insertion point.
MatchedNodes assignedChildren = GetMatchedNodesForPoint(mChild);
if (!assignedChildren.IsEmpty()) {
// Iterate through elements projected on insertion point.
mIndexInInserted = 1;
return assignedChildren[0];
}
// Insertion points inside fallback/default content
// are considered inactive and do not get assigned nodes.
mDefaultChild = mChild->GetFirstChild();
if (mDefaultChild) {
return mDefaultChild;
}
// If we have an insertion point with no assigned nodes and
// no default content, move on to the next node.
mChild = mChild->GetNextSibling();
} else {
// mChild is not an insertion point, thus it is the next node to
// return from this iterator.
break;
}
}
return mChild;
}
void
FlattenedChildIterator::Init(bool aIgnoreXBL)
{
if (aIgnoreXBL) {
return;
}
nsXBLBinding* binding =
mParent->OwnerDoc()->BindingManager()->GetBindingWithContent(mParent);
if (binding) {
nsIContent* anon = binding->GetAnonymousContent();
if (anon) {
mParent = anon;
mXBLInvolved = true;
}
}
// We set mXBLInvolved to true if either:
// - The node we're iterating has a binding with content attached to it.
// - The node is generated XBL content and has an <xbl:children> child.
if (!mXBLInvolved && mParent->GetBindingParent()) {
for (nsIContent* child = mParent->GetFirstChild();
child;
child = child->GetNextSibling()) {
if (child->NodeInfo()->Equals(nsGkAtoms::children, kNameSpaceID_XBL)) {
MOZ_ASSERT(child->GetBindingParent());
mXBLInvolved = true;
break;
}
}
}
}
bool
ExplicitChildIterator::Seek(nsIContent* aChildToFind)
{
if (aChildToFind->GetParent() == mParent &&
!aChildToFind->IsRootOfAnonymousSubtree()) {
// Fast path: just point ourselves to aChildToFind, which is a
// normal DOM child of ours.
MOZ_ASSERT(!ShadowRoot::IsShadowInsertionPoint(aChildToFind));
MOZ_ASSERT(!nsContentUtils::IsContentInsertionPoint(aChildToFind));
mChild = aChildToFind;
mIndexInInserted = 0;
mShadowIterator = nullptr;
mDefaultChild = nullptr;
mIsFirst = false;
return true;
}
// Can we add more fast paths here based on whether the parent of aChildToFind
// is a shadow insertion point or content insertion point?
// Slow path: just walk all our kids.
return Seek(aChildToFind, nullptr);
}
nsIContent*
ExplicitChildIterator::Get() const
{
MOZ_ASSERT(!mIsFirst);
if (mIndexInInserted) {
MatchedNodes assignedChildren = GetMatchedNodesForPoint(mChild);
return assignedChildren[mIndexInInserted - 1];
} else if (mShadowIterator) {
return mShadowIterator->Get();
}
return mDefaultChild ? mDefaultChild : mChild;
}
nsIContent*
ExplicitChildIterator::GetPreviousChild()
{
// If we're already in the inserted-children array, look there first
if (mIndexInInserted) {
// NB: mIndexInInserted points one past the last returned child so we need
// to look *two* indices back in order to return the previous child.
MatchedNodes assignedChildren = GetMatchedNodesForPoint(mChild);
if (--mIndexInInserted) {
return assignedChildren[mIndexInInserted - 1];
}
mChild = mChild->GetPreviousSibling();
} else if (mShadowIterator) {
nsIContent* previousChild = mShadowIterator->GetPreviousChild();
if (previousChild) {
return previousChild;
}
mShadowIterator = nullptr;
mChild = mChild->GetPreviousSibling();
} else if (mDefaultChild) {
// If we're already in default content, check if there are more nodes there
mDefaultChild = mDefaultChild->GetPreviousSibling();
if (mDefaultChild) {
return mDefaultChild;
}
mChild = mChild->GetPreviousSibling();
} else if (mIsFirst) { // at the beginning of the child list
return nullptr;
} else if (mChild) { // in the middle of the child list
mChild = mChild->GetPreviousSibling();
} else { // at the end of the child list
mChild = mParent->GetLastChild();
}
// Iterate until we find a non-insertion point, or an insertion point with
// content.
while (mChild) {
if (ShadowRoot::IsShadowInsertionPoint(mChild)) {
// If the current child being iterated is a shadow insertion point then
// the iterator needs to go into the projected ShadowRoot.
HTMLShadowElement* shadowElem = HTMLShadowElement::FromContent(mChild);
ShadowRoot* projectedShadow = shadowElem->GetOlderShadowRoot();
if (projectedShadow) {
// Create a ExplicitChildIterator that begins iterating from the end.
mShadowIterator = new ExplicitChildIterator(projectedShadow, false);
nsIContent* previousChild = mShadowIterator->GetPreviousChild();
if (previousChild) {
return previousChild;
}
mShadowIterator = nullptr;
}
mChild = mChild->GetPreviousSibling();
} else if (nsContentUtils::IsContentInsertionPoint(mChild)) {
// If the current child being iterated is a content insertion point
// then the iterator needs to return the nodes distributed into
// the content insertion point.
MatchedNodes assignedChildren = GetMatchedNodesForPoint(mChild);
if (!assignedChildren.IsEmpty()) {
mIndexInInserted = assignedChildren.Length();
return assignedChildren[mIndexInInserted - 1];
}
mDefaultChild = mChild->GetLastChild();
if (mDefaultChild) {
return mDefaultChild;
}
mChild = mChild->GetPreviousSibling();
} else {
// mChild is not an insertion point, thus it is the next node to
// return from this iterator.
break;
}
}
if (!mChild) {
mIsFirst = true;
}
return mChild;
}
nsIContent*
AllChildrenIterator::Get() const
{
switch (mPhase) {
case eAtBeforeKid: {
nsIFrame* frame = mOriginalContent->GetPrimaryFrame();
MOZ_ASSERT(frame, "No frame at eAtBeforeKid phase");
nsIFrame* beforeFrame = nsLayoutUtils::GetBeforeFrame(frame);
MOZ_ASSERT(beforeFrame, "No content before frame at eAtBeforeKid phase");
return beforeFrame->GetContent();
}
case eAtExplicitKids:
return ExplicitChildIterator::Get();
case eAtAnonKids:
return mAnonKids[mAnonKidsIdx];
case eAtAfterKid: {
nsIFrame* frame = mOriginalContent->GetPrimaryFrame();
MOZ_ASSERT(frame, "No frame at eAtAfterKid phase");
nsIFrame* afterFrame = nsLayoutUtils::GetAfterFrame(frame);
MOZ_ASSERT(afterFrame, "No content before frame at eAtBeforeKid phase");
return afterFrame->GetContent();
}
default:
return nullptr;
}
}
bool
AllChildrenIterator::Seek(nsIContent* aChildToFind)
{
if (mPhase == eAtBegin || mPhase == eAtBeforeKid) {
mPhase = eAtExplicitKids;
nsIFrame* frame = mOriginalContent->GetPrimaryFrame();
if (frame) {
nsIFrame* beforeFrame = nsLayoutUtils::GetBeforeFrame(frame);
if (beforeFrame) {
if (beforeFrame->GetContent() == aChildToFind) {
mPhase = eAtBeforeKid;
return true;
}
}
}
}
if (mPhase == eAtExplicitKids) {
if (ExplicitChildIterator::Seek(aChildToFind)) {
return true;
}
mPhase = eAtAnonKids;
}
nsIContent* child = nullptr;
do {
child = GetNextChild();
} while (child && child != aChildToFind);
return child == aChildToFind;
}
void
AllChildrenIterator::AppendNativeAnonymousChildren()
{
AppendNativeAnonymousChildrenFromFrame(mOriginalContent->GetPrimaryFrame());
// The root scroll frame is not the primary frame of the root element.
// Detect and handle this case.
if (!(mFlags & nsIContent::eSkipDocumentLevelNativeAnonymousContent) &&
mOriginalContent == mOriginalContent->OwnerDoc()->GetRootElement()) {
nsContentUtils::AppendDocumentLevelNativeAnonymousContentTo(
mOriginalContent->OwnerDoc(), mAnonKids);
}
}
void
AllChildrenIterator::AppendNativeAnonymousChildrenFromFrame(nsIFrame* aFrame)
{
nsIAnonymousContentCreator* ac = do_QueryFrame(aFrame);
if (ac) {
ac->AppendAnonymousContentTo(mAnonKids, mFlags);
}
}
nsIContent*
AllChildrenIterator::GetNextChild()
{
if (mPhase == eAtBegin) {
mPhase = eAtExplicitKids;
nsIFrame* frame = mOriginalContent->GetPrimaryFrame();
if (frame) {
nsIFrame* beforeFrame = nsLayoutUtils::GetBeforeFrame(frame);
if (beforeFrame) {
mPhase = eAtBeforeKid;
return beforeFrame->GetContent();
}
}
}
if (mPhase == eAtBeforeKid) {
// Advance into our explicit kids.
mPhase = eAtExplicitKids;
}
if (mPhase == eAtExplicitKids) {
nsIContent* kid = ExplicitChildIterator::GetNextChild();
if (kid) {
return kid;
}
mPhase = eAtAnonKids;
}
if (mPhase == eAtAnonKids) {
if (mAnonKids.IsEmpty()) {
MOZ_ASSERT(mAnonKidsIdx == UINT32_MAX);
AppendNativeAnonymousChildren();
mAnonKidsIdx = 0;
}
else {
if (mAnonKidsIdx == UINT32_MAX) {
mAnonKidsIdx = 0;
}
else {
mAnonKidsIdx++;
}
}
if (mAnonKidsIdx < mAnonKids.Length()) {
return mAnonKids[mAnonKidsIdx];
}
nsIFrame* frame = mOriginalContent->GetPrimaryFrame();
if (frame) {
nsIFrame* afterFrame = nsLayoutUtils::GetAfterFrame(frame);
if (afterFrame) {
mPhase = eAtAfterKid;
return afterFrame->GetContent();
}
}
}
mPhase = eAtEnd;
return nullptr;
}
nsIContent*
AllChildrenIterator::GetPreviousChild()
{
if (mPhase == eAtEnd) {
MOZ_ASSERT(mAnonKidsIdx == mAnonKids.Length());
mPhase = eAtAnonKids;
nsIFrame* frame = mOriginalContent->GetPrimaryFrame();
if (frame) {
nsIFrame* afterFrame = nsLayoutUtils::GetAfterFrame(frame);
if (afterFrame) {
mPhase = eAtAfterKid;
return afterFrame->GetContent();
}
}
}
if (mPhase == eAtAfterKid) {
mPhase = eAtAnonKids;
}
if (mPhase == eAtAnonKids) {
if (mAnonKids.IsEmpty()) {
AppendNativeAnonymousChildren();
mAnonKidsIdx = mAnonKids.Length();
}
// If 0 then it turns into UINT32_MAX, which indicates the iterator is
// before the anonymous children.
--mAnonKidsIdx;
if (mAnonKidsIdx < mAnonKids.Length()) {
return mAnonKids[mAnonKidsIdx];
}
mPhase = eAtExplicitKids;
}
if (mPhase == eAtExplicitKids) {
nsIContent* kid = ExplicitChildIterator::GetPreviousChild();
if (kid) {
return kid;
}
nsIFrame* frame = mOriginalContent->GetPrimaryFrame();
if (frame) {
nsIFrame* beforeFrame = nsLayoutUtils::GetBeforeFrame(frame);
if (beforeFrame) {
mPhase = eAtBeforeKid;
return beforeFrame->GetContent();
}
}
}
mPhase = eAtBegin;
return nullptr;
}
static bool
IsNativeAnonymousImplementationOfPseudoElement(nsIContent* aContent)
{
// First, we need a frame. This leads to the tricky issue of what we can
// infer if the frame is null.
//
// Unlike regular nodes, native anonymous content (NAC) gets created during
// frame construction, which happens after the main style traversal. This
// means that we have to manually resolve style for those nodes shortly after
// they're created, either by (a) invoking ResolvePseudoElementStyle (for PE
// NAC), or (b) handing the subtree off to Servo for a mini-traversal (for
// non-PE NAC). We have assertions in nsCSSFrameConstructor that we don't do
// both.
//
// Once that happens, the NAC has a frame. So if we have no frame here,
// we're either not NAC, or in the process of doing (b). Either way, this
// isn't a PE.
nsIFrame* f = aContent->GetPrimaryFrame();
if (!f) {
return false;
}
// Get the pseudo type.
CSSPseudoElementType pseudoType = f->StyleContext()->GetPseudoType();
// In general nodes never get anonymous box style. However, there are a few
// special cases:
//
// * We somewhat-confusingly give text nodes a style context tagged with
// ":-moz-text", so we need to check for the anonymous box case here.
// * The primary frame for table elements is an anonymous box that inherits
// from the table's style.
if (pseudoType == CSSPseudoElementType::InheritingAnonBox) {
MOZ_ASSERT(f->StyleContext()->GetPseudo() == nsCSSAnonBoxes::mozText ||
f->StyleContext()->GetPseudo() == nsCSSAnonBoxes::tableWrapper);
return false;
}
MOZ_ASSERT(pseudoType != CSSPseudoElementType::NonInheritingAnonBox);
// Finally check the actual pseudo type.
bool isImpl = pseudoType != CSSPseudoElementType::NotPseudo;
MOZ_ASSERT_IF(isImpl, aContent->IsRootOfNativeAnonymousSubtree());
return isImpl;
}
/* static */ bool
StyleChildrenIterator::IsNeeded(const Element* aElement)
{
// If the node is in an anonymous subtree, we conservatively return true to
// handle insertion points.
if (aElement->IsInAnonymousSubtree()) {
return true;
}
// If the node has an XBL binding with anonymous content return true.
if (aElement->HasFlag(NODE_MAY_BE_IN_BINDING_MNGR)) {
nsBindingManager* manager = aElement->OwnerDoc()->BindingManager();
nsXBLBinding* binding = manager->GetBindingWithContent(aElement);
if (binding && binding->GetAnonymousContent()) {
return true;
}
}
// If the node has native anonymous content, return true.
nsIAnonymousContentCreator* ac = do_QueryFrame(aElement->GetPrimaryFrame());
if (ac) {
return true;
}
return false;
}
nsIContent*
StyleChildrenIterator::GetNextChild()
{
while (nsIContent* child = AllChildrenIterator::GetNextChild()) {
if (IsNativeAnonymousImplementationOfPseudoElement(child)) {
// Skip any native-anonymous children that are used to implement pseudo-
// elements. These match pseudo-element selectors instead of being
// considered a child of their host, and thus the style system needs to
// handle them separately.
} else {
return child;
}
}
return nullptr;
}
} // namespace dom
} // namespace mozilla