gecko/dom/base/ChildIterator.cpp

375 lines
12 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"
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(static_cast<HTMLContentElement*>(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 = static_cast<HTMLShadowElement*>(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;
}
}
}
}
void
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;
}
// 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.
Seek(aChildToFind, nullptr);
}
nsIContent*
ExplicitChildIterator::Get()
{
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 = static_cast<HTMLShadowElement*>(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::GetNextChild()
{
if (mPhase == eNeedBeforeKid) {
mPhase = eNeedExplicitKids;
nsIFrame* frame = mOriginalContent->GetPrimaryFrame();
if (frame) {
nsIFrame* beforeFrame = nsLayoutUtils::GetBeforeFrame(frame);
if (beforeFrame) {
return beforeFrame->GetContent();
}
}
}
if (mPhase == eNeedExplicitKids) {
nsIContent* kid = ExplicitChildIterator::GetNextChild();
if (kid) {
return kid;
}
mPhase = eNeedAnonKids;
}
if (mPhase == eNeedAnonKids) {
if (mAnonKids.IsEmpty()) {
nsIAnonymousContentCreator* ac =
do_QueryFrame(mOriginalContent->GetPrimaryFrame());
if (ac) {
ac->AppendAnonymousContentTo(mAnonKids, mFlags);
}
}
if (!mAnonKids.IsEmpty()) {
nsIContent* nextKid = mAnonKids[0];
mAnonKids.RemoveElementAt(0);
if (mAnonKids.IsEmpty()) {
mPhase = eNeedAfterKid;
}
return nextKid;
}
mPhase = eNeedAfterKid;
}
if (mPhase == eNeedAfterKid) {
mPhase = eDone;
nsIFrame* frame = mOriginalContent->GetPrimaryFrame();
if (frame) {
nsIFrame* afterFrame = nsLayoutUtils::GetAfterFrame(frame);
if (afterFrame) {
return afterFrame->GetContent();
}
}
}
return nullptr;
}
} // namespace dom
} // namespace mozilla