/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */ // vim:cindent:ai:sw=4:ts=4:et: /* 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/. */ /* implementation of CSS counters (for numbering things) */ #ifndef nsCounterManager_h_ #define nsCounterManager_h_ #include "mozilla/Attributes.h" #include "nsGenConList.h" #include "nsClassHashtable.h" #include "mozilla/Likely.h" #include "CounterStyleManager.h" class nsCounterList; struct nsCounterUseNode; struct nsCounterChangeNode; struct nsCounterNode : public nsGenConNode { enum Type { RESET, // a "counter number" pair in 'counter-reset' INCREMENT, // a "counter number" pair in 'counter-increment' USE // counter() or counters() in 'content' }; Type mType; // Counter value after this node int32_t mValueAfter; // mScopeStart points to the node (usually a RESET, but not in the // case of an implied 'counter-reset') that created the scope for // this element (for a RESET, its outer scope, i.e., the one it is // inside rather than the one it creates). // May be null for all types, but only when mScopePrev is also null. // Being null for a non-RESET means that it is an implied // 'counter-reset'. Being null for a RESET means it has no outer // scope. nsCounterNode *mScopeStart; // mScopePrev points to the previous node that is in the same scope, // or for a RESET, the previous node in the scope outside of the // reset. // May be null for all types, but only when mScopeStart is also // null. Following the mScopePrev links will eventually lead to // mScopeStart. Being null for a non-RESET means that it is an // implied 'counter-reset'. Being null for a RESET means it has no // outer scope. nsCounterNode *mScopePrev; inline nsCounterUseNode* UseNode(); inline nsCounterChangeNode* ChangeNode(); // For RESET and INCREMENT nodes, aPseudoFrame need not be a // pseudo-element, and aContentIndex represents the index within the // 'counter-reset' or 'counter-increment' property instead of within // the 'content' property but offset to ensure that (reset, // increment, use) sort in that order. (This slight weirdness // allows sharing a lot of code with 'quotes'.) nsCounterNode(int32_t aContentIndex, Type aType) : nsGenConNode(aContentIndex) , mType(aType) , mValueAfter(0) , mScopeStart(nullptr) , mScopePrev(nullptr) { } // to avoid virtual function calls in the common case inline void Calc(nsCounterList* aList); }; struct nsCounterUseNode : public nsCounterNode { // The same structure passed through the style system: an array // containing the values in the counter() or counters() in the order // given in the CSS spec. RefPtr<nsCSSValue::Array> mCounterFunction; nsPresContext* mPresContext; RefPtr<mozilla::CounterStyle> mCounterStyle; // false for counter(), true for counters() bool mAllCounters; // args go directly to member variables here and of nsGenConNode nsCounterUseNode(nsPresContext* aPresContext, nsCSSValue::Array* aCounterFunction, uint32_t aContentIndex, bool aAllCounters) : nsCounterNode(aContentIndex, USE) , mCounterFunction(aCounterFunction) , mPresContext(aPresContext) , mCounterStyle(nullptr) , mAllCounters(aAllCounters) { NS_ASSERTION(aContentIndex <= INT32_MAX, "out of range"); } virtual bool InitTextFrame(nsGenConList* aList, nsIFrame* aPseudoFrame, nsIFrame* aTextFrame) override; mozilla::CounterStyle* GetCounterStyle(); void SetCounterStyleDirty() { mCounterStyle = nullptr; } // assign the correct |mValueAfter| value to a node that has been inserted // Should be called immediately after calling |Insert|. void Calc(nsCounterList* aList); // The text that should be displayed for this counter. void GetText(nsString& aResult); }; struct nsCounterChangeNode : public nsCounterNode { int32_t mChangeValue; // the numeric value of the increment or reset // |aPseudoFrame| is not necessarily a pseudo-element's frame, but // since it is for every other subclass of nsGenConNode, we follow // the naming convention here. // |aPropIndex| is the index of the value within the list in the // 'counter-increment' or 'counter-reset' property. nsCounterChangeNode(nsIFrame* aPseudoFrame, nsCounterNode::Type aChangeType, int32_t aChangeValue, int32_t aPropIndex) : nsCounterNode(// Fake a content index for resets and increments // that comes before all the real content, with // the resets first, in order, and then the increments. aPropIndex + (aChangeType == RESET ? (INT32_MIN) : (INT32_MIN / 2)), aChangeType) , mChangeValue(aChangeValue) { NS_ASSERTION(aPropIndex >= 0, "out of range"); NS_ASSERTION(aChangeType == INCREMENT || aChangeType == RESET, "bad type"); mPseudoFrame = aPseudoFrame; CheckFrameAssertions(); } // assign the correct |mValueAfter| value to a node that has been inserted // Should be called immediately after calling |Insert|. void Calc(nsCounterList* aList); }; inline nsCounterUseNode* nsCounterNode::UseNode() { NS_ASSERTION(mType == USE, "wrong type"); return static_cast<nsCounterUseNode*>(this); } inline nsCounterChangeNode* nsCounterNode::ChangeNode() { NS_ASSERTION(mType == INCREMENT || mType == RESET, "wrong type"); return static_cast<nsCounterChangeNode*>(this); } inline void nsCounterNode::Calc(nsCounterList* aList) { if (mType == USE) UseNode()->Calc(aList); else ChangeNode()->Calc(aList); } class nsCounterList : public nsGenConList { public: nsCounterList() : nsGenConList(), mDirty(false) {} void Insert(nsCounterNode* aNode) { nsGenConList::Insert(aNode); // Don't SetScope if we're dirty -- we'll reset all the scopes anyway, // and we can't usefully compute scopes right now. if (MOZ_LIKELY(!IsDirty())) { SetScope(aNode); } } nsCounterNode* First() { return static_cast<nsCounterNode*>(mList.getFirst()); } static nsCounterNode* Next(nsCounterNode* aNode) { return static_cast<nsCounterNode*>(nsGenConList::Next(aNode)); } static nsCounterNode* Prev(nsCounterNode* aNode) { return static_cast<nsCounterNode*>(nsGenConList::Prev(aNode)); } static int32_t ValueBefore(nsCounterNode* aNode) { return aNode->mScopePrev ? aNode->mScopePrev->mValueAfter : 0; } // Correctly set |aNode->mScopeStart| and |aNode->mScopePrev| void SetScope(nsCounterNode *aNode); // Recalculate |mScopeStart|, |mScopePrev|, and |mValueAfter| for // all nodes and update text in text content nodes. void RecalcAll(); bool IsDirty() { return mDirty; } void SetDirty() { mDirty = true; } private: bool mDirty; }; /** * The counter manager maintains an |nsCounterList| for each named * counter to keep track of all scopes with that name. */ class nsCounterManager { public: nsCounterManager(); // Returns true if dirty bool AddCounterResetsAndIncrements(nsIFrame *aFrame); // Gets the appropriate counter list, creating it if necessary. // Guaranteed to return non-null. (Uses an infallible hashtable API.) nsCounterList* CounterListFor(const nsSubstring& aCounterName); // Clean up data in any dirty counter lists. void RecalcAll(); // Set all counter styles dirty void SetAllCounterStylesDirty(); // Destroy nodes for the frame in any lists, and return whether any // nodes were destroyed. bool DestroyNodesFor(nsIFrame *aFrame); // Clear all data. void Clear() { mNames.Clear(); } #ifdef DEBUG void Dump(); #endif static int32_t IncrementCounter(int32_t aOldValue, int32_t aIncrement) { // Addition of unsigned values is defined to be arithmetic // modulo 2^bits (C++ 2011, 3.9.1 [basic.fundamental], clause 4); // addition of signed values is undefined (and clang does // something very strange if we use it here). Likewise integral // conversion from signed to unsigned is also defined as modulo // 2^bits (C++ 2011, 4.7 [conv.integral], clause 2); conversion // from unsigned to signed is however undefined (ibid., clause 3), // but to do what we want we must nonetheless depend on that // small piece of undefined behavior. int32_t newValue = int32_t(uint32_t(aOldValue) + uint32_t(aIncrement)); // The CSS Working Group resolved that a counter-increment that // exceeds internal limits should not increment at all. // http://lists.w3.org/Archives/Public/www-style/2013Feb/0392.html // (This means, for example, that if aIncrement is 5, the // counter will get stuck at the largest multiple of 5 less than // the maximum 32-bit integer.) if ((aIncrement > 0) != (newValue > aOldValue)) { newValue = aOldValue; } return newValue; } private: // for |AddCounterResetsAndIncrements| only bool AddResetOrIncrement(nsIFrame* aFrame, int32_t aIndex, const nsStyleCounterData& aCounterData, nsCounterNode::Type aType); nsClassHashtable<nsStringHashKey, nsCounterList> mNames; }; #endif /* nsCounterManager_h_ */