/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ // 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) */
class nsCounterList; struct nsCounterUseNode; struct nsCounterChangeNode;
namespace mozilla {
class ContainStyleScope;
} // namespace mozilla
struct nsCounterNode : public nsGenConNode { enum Type {
RESET, // a "counter number" pair in 'counter-reset'
INCREMENT, // a "counter number" pair in 'counter-increment'
SET, // a "counter number" pair in 'counter-set'
USE // counter() or counters() in 'content'
};
Type mType;
// Counter value after this node
int32_t mValueAfter = 0;
// 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 = nullptr;
// 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 = nullptr;
// Whether or not this node's scope crosses `contain: style` boundaries. // This can happen for USE nodes that come before any other types of // nodes in a `contain: style` boundary's list. bool mCrossesContainStyleBoundaries = false;
// For RESET, INCREMENT and SET nodes, aPseudoFrame need not be a // pseudo-element, and aContentIndex represents the index within the // 'counter-reset', 'counter-increment' or 'counter-set' property // instead of within the 'content' property but offset to ensure // that (reset, increment, set, use) sort in that order. // It is zero for legacy bullet USE counter nodes. // (This slight weirdness allows sharing a lot of code with 'quotes'.)
nsCounterNode(int32_t aContentIndex, Type aType)
: nsGenConNode(aContentIndex), mType(aType) {}
// to avoid virtual function calls in the common case inlinevoid Calc(nsCounterList* aList, bool aNotify);
// Is this a RESET node for a content-based (i.e. without a start value) // reversed() counter? inlinebool IsContentBasedReset();
// Is this a RESET node for a reversed() counter? inlinebool IsReversed();
// Is this an INCREMENT node that needs to be initialized to -1 or 1 // depending on if our scope is reversed() or not? inlinebool IsUnitializedIncrementNode();
};
struct nsCounterUseNode : public nsCounterNode {
mozilla::StyleCounterStyle mCounterStyle;
nsString mSeparator;
// false for counter(), true for counters() bool mAllCounters = false;
// args go directly to member variables here and of nsGenConNode
nsCounterUseNode(const mozilla::StyleCounterStyle& aCounterStyle,
nsString aSeparator, uint32_t aContentIndex, bool aAllCounters)
: nsCounterNode(aContentIndex, USE),
mCounterStyle(aCounterStyle),
mSeparator(std::move(aSeparator)),
mAllCounters(aAllCounters) {
NS_ASSERTION(aContentIndex <= INT32_MAX, "out of range");
}
// assign the correct |mValueAfter| value to a node that has been inserted, // and update the value of the text node, notifying if `aNotify` is true. // Should be called immediately after calling |Insert|. void Calc(nsCounterList* aList, bool aNotify);
// The text that should be displayed for this counter. void GetText(nsString& aResult); void GetText(mozilla::WritingMode aWM, mozilla::CounterStyle* aStyle,
nsString& aResult);
};
struct nsCounterChangeNode : public nsCounterNode { // |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', 'counter-reset' or 'counter-set' property.
nsCounterChangeNode(nsIFrame* aPseudoFrame, nsCounterNode::Type aChangeType,
int32_t aChangeValue, int32_t aPropIndex, bool aIsReversed)
: nsCounterNode( // Fake a content index for resets, increments and sets // that comes before all the real content, with // the resets first, in order, and then the increments // and then the sets.
aPropIndex + (aChangeType == RESET ? (INT32_MIN)
: (aChangeType == INCREMENT
? ((INT32_MIN / 3) * 2)
: INT32_MIN / 3)),
aChangeType),
mChangeValue(aChangeValue),
mIsReversed(aIsReversed),
mSeenSetNode(false) {
NS_ASSERTION(aPropIndex >= 0, "out of range");
NS_ASSERTION(
aChangeType == INCREMENT || aChangeType == SET || 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);
// The numeric value of the INCREMENT, SET or RESET. // Note: numeric_limits<int32_t>::min() is used for content-based reversed() // RESET nodes, and temporarily on INCREMENT nodes to signal that it should be // initialized to -1 or 1 depending on if the scope is reversed() or not.
int32_t mChangeValue;
// True if the counter is reversed(). Only used on RESET nodes. bool mIsReversed : 1; // True if we've seen a SET node during the initialization of // an IsContentBasedReset() node; always false on other nodes. bool mSeenSetNode : 1;
};
class nsCounterList : public nsGenConList { public:
nsCounterList(nsAtom* aCounterName, mozilla::ContainStyleScope* aScope)
: mCounterName(aCounterName), mScope(aScope) {
MOZ_ASSERT(aScope);
}
// Return the first node for aFrame on this list, or nullptr.
nsCounterNode* GetFirstNodeFor(nsIFrame* aFrame) const { returnstatic_cast<nsCounterNode*>(nsGenConList::GetFirstNodeFor(aFrame));
}
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);
}
}
/** * The counter manager maintains an |nsCounterList| for each named * counter to keep track of all scopes with that name.
*/ class nsCounterManager { public: explicit nsCounterManager(mozilla::ContainStyleScope* scope)
: mScope(scope) {}
// Returns true if dirty bool AddCounterChanges(nsIFrame* aFrame);
// Gets the appropriate counter list, creating it if necessary. // Guaranteed to return non-null. (Uses an infallible hashtable API.)
nsCounterList* GetOrCreateCounterList(nsAtom* aCounterName);
// Gets the appropriate counter list, returning null if it doesn't exist.
nsCounterList* GetCounterList(nsAtom* aCounterName);
// Clean up data in any dirty counter lists. void RecalcAll();
// Set all counter lists dirty void SetAllDirty();
// 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 ACCESSIBILITY // Set |aOrdinal| to the first used counter value for the given frame and // return true. If no USE node for the given frame can be found, return false // and do not change the value of |aOrdinal|. bool GetFirstCounterValueForFrame(nsIFrame* aFrame,
mozilla::CounterValue& aOrdinal) const; #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;
}
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