diff options
Diffstat (limited to 'layout/base/nsGenConList.cpp')
| -rw-r--r-- | layout/base/nsGenConList.cpp | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/layout/base/nsGenConList.cpp b/layout/base/nsGenConList.cpp new file mode 100644 index 000000000..bdb47e183 --- /dev/null +++ b/layout/base/nsGenConList.cpp @@ -0,0 +1,192 @@ +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +// vim:cindent:ts=2:et:sw=2: +/* 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/. */ + +/* base class for nsCounterList and nsQuoteList */ + +#include "nsGenConList.h" +#include "nsLayoutUtils.h" +#include "nsIContent.h" + +void +nsGenConList::Clear() +{ + // Delete entire list. + mNodes.Clear(); + while (nsGenConNode* node = mList.popFirst()) { + delete node; + } + mSize = 0; +} + +bool +nsGenConList::DestroyNodesFor(nsIFrame* aFrame) +{ + // This algorithm relies on the invariant that nodes of a frame are + // put contiguously in the linked list. This is guaranteed because + // each frame is mapped to only one (nsIContent, pseudoType) pair, + // and the nodes in the linked list are put in the tree order based + // on that pair and offset inside frame. + nsGenConNode* node = mNodes.GetAndRemove(aFrame).valueOr(nullptr); + if (!node) { + return false; + } + MOZ_ASSERT(node->mPseudoFrame == aFrame); + + while (node && node->mPseudoFrame == aFrame) { + nsGenConNode* nextNode = Next(node); + Destroy(node); + node = nextNode; + } + + return true; +} + +/** + * Compute the type of the pseudo and the content for the pseudo that + * we'll use for comparison purposes. + * @param aContent the content to use is stored here; it's the element + * that generated the ::before or ::after content, or (if not for generated + * content), the frame's own element + * @return -1 for ::before, +1 for ::after, and 0 otherwise. + */ +inline int32_t PseudoCompareType(nsIFrame* aFrame, nsIContent** aContent) +{ + nsIAtom *pseudo = aFrame->StyleContext()->GetPseudo(); + if (pseudo == nsCSSPseudoElements::before) { + *aContent = aFrame->GetContent()->GetParent(); + return -1; + } + if (pseudo == nsCSSPseudoElements::after) { + *aContent = aFrame->GetContent()->GetParent(); + return 1; + } + *aContent = aFrame->GetContent(); + return 0; +} + +/* static */ bool +nsGenConList::NodeAfter(const nsGenConNode* aNode1, const nsGenConNode* aNode2) +{ + nsIFrame *frame1 = aNode1->mPseudoFrame; + nsIFrame *frame2 = aNode2->mPseudoFrame; + if (frame1 == frame2) { + NS_ASSERTION(aNode2->mContentIndex != aNode1->mContentIndex, "identical"); + return aNode1->mContentIndex > aNode2->mContentIndex; + } + nsIContent *content1; + nsIContent *content2; + int32_t pseudoType1 = PseudoCompareType(frame1, &content1); + int32_t pseudoType2 = PseudoCompareType(frame2, &content2); + if (pseudoType1 == 0 || pseudoType2 == 0) { + if (content1 == content2) { + NS_ASSERTION(pseudoType1 != pseudoType2, "identical"); + return pseudoType2 == 0; + } + // We want to treat an element as coming before its :before (preorder + // traversal), so treating both as :before now works. + if (pseudoType1 == 0) pseudoType1 = -1; + if (pseudoType2 == 0) pseudoType2 = -1; + } else { + if (content1 == content2) { + NS_ASSERTION(pseudoType1 != pseudoType2, "identical"); + return pseudoType1 == 1; + } + } + // XXX Switch to the frame version of DoCompareTreePosition? + int32_t cmp = nsLayoutUtils::DoCompareTreePosition(content1, content2, + pseudoType1, -pseudoType2); + MOZ_ASSERT(cmp != 0, "same content, different frames"); + return cmp > 0; +} + +void +nsGenConList::Insert(nsGenConNode* aNode) +{ + // Check for append. + if (mList.isEmpty() || NodeAfter(aNode, mList.getLast())) { + mList.insertBack(aNode); + } else { + // Binary search. + + // the range of indices at which |aNode| could end up. + // (We already know it can't be at index mSize.) + uint32_t first = 0, last = mSize - 1; + + // A cursor to avoid walking more than the length of the list. + nsGenConNode* curNode = mList.getLast(); + uint32_t curIndex = mSize - 1; + + while (first != last) { + uint32_t test = (first + last) / 2; + if (last == curIndex) { + for ( ; curIndex != test; --curIndex) + curNode = Prev(curNode); + } else { + for ( ; curIndex != test; ++curIndex) + curNode = Next(curNode); + } + + if (NodeAfter(aNode, curNode)) { + first = test + 1; + // if we exit the loop, we need curNode to be right + ++curIndex; + curNode = Next(curNode); + } else { + last = test; + } + } + curNode->setPrevious(aNode); + } + ++mSize; + + // Set the mapping only if it is the first node of the frame. + // The DEBUG blocks below are for ensuring the invariant required by + // nsGenConList::DestroyNodesFor. See comment there. + if (IsFirst(aNode) || + Prev(aNode)->mPseudoFrame != aNode->mPseudoFrame) { +#ifdef DEBUG + if (nsGenConNode* oldFrameFirstNode = mNodes.Get(aNode->mPseudoFrame)) { + MOZ_ASSERT(Next(aNode) == oldFrameFirstNode, + "oldFrameFirstNode should now be immediately after " + "the newly-inserted one."); + } else { + // If the node is not the only node in the list. + if (!IsFirst(aNode) || !IsLast(aNode)) { + nsGenConNode* nextNode = Next(aNode); + MOZ_ASSERT(!nextNode || nextNode->mPseudoFrame != aNode->mPseudoFrame, + "There shouldn't exist any node for this frame."); + // If the node is neither the first nor the last node + if (!IsFirst(aNode) && !IsLast(aNode)) { + MOZ_ASSERT(Prev(aNode)->mPseudoFrame != nextNode->mPseudoFrame, + "New node should not break contiguity of nodes of " + "the same frame."); + } + } + } +#endif + mNodes.Put(aNode->mPseudoFrame, aNode); + } else { +#ifdef DEBUG + nsGenConNode* frameFirstNode = mNodes.Get(aNode->mPseudoFrame); + MOZ_ASSERT(frameFirstNode, "There should exist node map for the frame."); + for (nsGenConNode* curNode = Prev(aNode); + curNode != frameFirstNode; curNode = Prev(curNode)) { + MOZ_ASSERT(curNode->mPseudoFrame == aNode->mPseudoFrame, + "Every node between frameFirstNode and the new node inserted " + "should refer to the same frame."); + MOZ_ASSERT(!IsFirst(curNode), + "The newly-inserted node should be in a contiguous run after " + "frameFirstNode, thus frameFirstNode should be reached before " + "the first node of mList."); + } +#endif + } + + NS_ASSERTION(IsFirst(aNode) || NodeAfter(aNode, Prev(aNode)), + "sorting error"); + NS_ASSERTION(IsLast(aNode) || NodeAfter(Next(aNode), aNode), + "sorting error"); +} |