1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/layout/base/nsCounterManager.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,266 @@
1.4 +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
1.5 +// vim:cindent:ai:sw=4:ts=4:et:
1.6 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.7 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.8 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.9 +
1.10 +/* implementation of CSS counters (for numbering things) */
1.11 +
1.12 +#ifndef nsCounterManager_h_
1.13 +#define nsCounterManager_h_
1.14 +
1.15 +#include "mozilla/Attributes.h"
1.16 +#include "nsGenConList.h"
1.17 +#include "nsAutoPtr.h"
1.18 +#include "nsClassHashtable.h"
1.19 +#include "mozilla/Likely.h"
1.20 +
1.21 +class nsCounterList;
1.22 +struct nsCounterUseNode;
1.23 +struct nsCounterChangeNode;
1.24 +
1.25 +struct nsCounterNode : public nsGenConNode {
1.26 + enum Type {
1.27 + RESET, // a "counter number" pair in 'counter-reset'
1.28 + INCREMENT, // a "counter number" pair in 'counter-increment'
1.29 + USE // counter() or counters() in 'content'
1.30 + };
1.31 +
1.32 + Type mType;
1.33 +
1.34 + // Counter value after this node
1.35 + int32_t mValueAfter;
1.36 +
1.37 + // mScopeStart points to the node (usually a RESET, but not in the
1.38 + // case of an implied 'counter-reset') that created the scope for
1.39 + // this element (for a RESET, its outer scope, i.e., the one it is
1.40 + // inside rather than the one it creates).
1.41 +
1.42 + // May be null for all types, but only when mScopePrev is also null.
1.43 + // Being null for a non-RESET means that it is an implied
1.44 + // 'counter-reset'. Being null for a RESET means it has no outer
1.45 + // scope.
1.46 + nsCounterNode *mScopeStart;
1.47 +
1.48 + // mScopePrev points to the previous node that is in the same scope,
1.49 + // or for a RESET, the previous node in the scope outside of the
1.50 + // reset.
1.51 +
1.52 + // May be null for all types, but only when mScopeStart is also
1.53 + // null. Following the mScopePrev links will eventually lead to
1.54 + // mScopeStart. Being null for a non-RESET means that it is an
1.55 + // implied 'counter-reset'. Being null for a RESET means it has no
1.56 + // outer scope.
1.57 + nsCounterNode *mScopePrev;
1.58 +
1.59 + inline nsCounterUseNode* UseNode();
1.60 + inline nsCounterChangeNode* ChangeNode();
1.61 +
1.62 + // For RESET and INCREMENT nodes, aPseudoFrame need not be a
1.63 + // pseudo-element, and aContentIndex represents the index within the
1.64 + // 'counter-reset' or 'counter-increment' property instead of within
1.65 + // the 'content' property but offset to ensure that (reset,
1.66 + // increment, use) sort in that order. (This slight weirdness
1.67 + // allows sharing a lot of code with 'quotes'.)
1.68 + nsCounterNode(int32_t aContentIndex, Type aType)
1.69 + : nsGenConNode(aContentIndex)
1.70 + , mType(aType)
1.71 + , mValueAfter(0)
1.72 + , mScopeStart(nullptr)
1.73 + , mScopePrev(nullptr)
1.74 + {
1.75 + }
1.76 +
1.77 + // to avoid virtual function calls in the common case
1.78 + inline void Calc(nsCounterList* aList);
1.79 +};
1.80 +
1.81 +struct nsCounterUseNode : public nsCounterNode {
1.82 + // The same structure passed through the style system: an array
1.83 + // containing the values in the counter() or counters() in the order
1.84 + // given in the CSS spec.
1.85 + nsRefPtr<nsCSSValue::Array> mCounterStyle;
1.86 +
1.87 + // false for counter(), true for counters()
1.88 + bool mAllCounters;
1.89 +
1.90 + // args go directly to member variables here and of nsGenConNode
1.91 + nsCounterUseNode(nsCSSValue::Array* aCounterStyle,
1.92 + uint32_t aContentIndex, bool aAllCounters)
1.93 + : nsCounterNode(aContentIndex, USE)
1.94 + , mCounterStyle(aCounterStyle)
1.95 + , mAllCounters(aAllCounters)
1.96 + {
1.97 + NS_ASSERTION(aContentIndex <= INT32_MAX, "out of range");
1.98 + }
1.99 +
1.100 + virtual bool InitTextFrame(nsGenConList* aList,
1.101 + nsIFrame* aPseudoFrame, nsIFrame* aTextFrame) MOZ_OVERRIDE;
1.102 +
1.103 + // assign the correct |mValueAfter| value to a node that has been inserted
1.104 + // Should be called immediately after calling |Insert|.
1.105 + void Calc(nsCounterList* aList);
1.106 +
1.107 + // The text that should be displayed for this counter.
1.108 + void GetText(nsString& aResult);
1.109 +};
1.110 +
1.111 +struct nsCounterChangeNode : public nsCounterNode {
1.112 + int32_t mChangeValue; // the numeric value of the increment or reset
1.113 +
1.114 + // |aPseudoFrame| is not necessarily a pseudo-element's frame, but
1.115 + // since it is for every other subclass of nsGenConNode, we follow
1.116 + // the naming convention here.
1.117 + // |aPropIndex| is the index of the value within the list in the
1.118 + // 'counter-increment' or 'counter-reset' property.
1.119 + nsCounterChangeNode(nsIFrame* aPseudoFrame,
1.120 + nsCounterNode::Type aChangeType,
1.121 + int32_t aChangeValue,
1.122 + int32_t aPropIndex)
1.123 + : nsCounterNode(// Fake a content index for resets and increments
1.124 + // that comes before all the real content, with
1.125 + // the resets first, in order, and then the increments.
1.126 + aPropIndex + (aChangeType == RESET
1.127 + ? (INT32_MIN)
1.128 + : (INT32_MIN / 2)),
1.129 + aChangeType)
1.130 + , mChangeValue(aChangeValue)
1.131 + {
1.132 + NS_ASSERTION(aPropIndex >= 0, "out of range");
1.133 + NS_ASSERTION(aChangeType == INCREMENT || aChangeType == RESET,
1.134 + "bad type");
1.135 + mPseudoFrame = aPseudoFrame;
1.136 + CheckFrameAssertions();
1.137 + }
1.138 +
1.139 + // assign the correct |mValueAfter| value to a node that has been inserted
1.140 + // Should be called immediately after calling |Insert|.
1.141 + void Calc(nsCounterList* aList);
1.142 +};
1.143 +
1.144 +inline nsCounterUseNode* nsCounterNode::UseNode()
1.145 +{
1.146 + NS_ASSERTION(mType == USE, "wrong type");
1.147 + return static_cast<nsCounterUseNode*>(this);
1.148 +}
1.149 +
1.150 +inline nsCounterChangeNode* nsCounterNode::ChangeNode()
1.151 +{
1.152 + NS_ASSERTION(mType == INCREMENT || mType == RESET, "wrong type");
1.153 + return static_cast<nsCounterChangeNode*>(this);
1.154 +}
1.155 +
1.156 +inline void nsCounterNode::Calc(nsCounterList* aList)
1.157 +{
1.158 + if (mType == USE)
1.159 + UseNode()->Calc(aList);
1.160 + else
1.161 + ChangeNode()->Calc(aList);
1.162 +}
1.163 +
1.164 +class nsCounterList : public nsGenConList {
1.165 +public:
1.166 + nsCounterList() : nsGenConList(),
1.167 + mDirty(false)
1.168 + {}
1.169 +
1.170 + void Insert(nsCounterNode* aNode) {
1.171 + nsGenConList::Insert(aNode);
1.172 + // Don't SetScope if we're dirty -- we'll reset all the scopes anyway,
1.173 + // and we can't usefully compute scopes right now.
1.174 + if (MOZ_LIKELY(!IsDirty())) {
1.175 + SetScope(aNode);
1.176 + }
1.177 + }
1.178 +
1.179 + nsCounterNode* First() {
1.180 + return static_cast<nsCounterNode*>(mFirstNode);
1.181 + }
1.182 +
1.183 + static nsCounterNode* Next(nsCounterNode* aNode) {
1.184 + return static_cast<nsCounterNode*>(nsGenConList::Next(aNode));
1.185 + }
1.186 + static nsCounterNode* Prev(nsCounterNode* aNode) {
1.187 + return static_cast<nsCounterNode*>(nsGenConList::Prev(aNode));
1.188 + }
1.189 +
1.190 + static int32_t ValueBefore(nsCounterNode* aNode) {
1.191 + return aNode->mScopePrev ? aNode->mScopePrev->mValueAfter : 0;
1.192 + }
1.193 +
1.194 + // Correctly set |aNode->mScopeStart| and |aNode->mScopePrev|
1.195 + void SetScope(nsCounterNode *aNode);
1.196 +
1.197 + // Recalculate |mScopeStart|, |mScopePrev|, and |mValueAfter| for
1.198 + // all nodes and update text in text content nodes.
1.199 + void RecalcAll();
1.200 +
1.201 + bool IsDirty() { return mDirty; }
1.202 + void SetDirty() { mDirty = true; }
1.203 +
1.204 +private:
1.205 + bool mDirty;
1.206 +};
1.207 +
1.208 +/**
1.209 + * The counter manager maintains an |nsCounterList| for each named
1.210 + * counter to keep track of all scopes with that name.
1.211 + */
1.212 +class nsCounterManager {
1.213 +public:
1.214 + nsCounterManager();
1.215 + // Returns true if dirty
1.216 + bool AddCounterResetsAndIncrements(nsIFrame *aFrame);
1.217 +
1.218 + // Gets the appropriate counter list, creating it if necessary.
1.219 + // Returns null only on out-of-memory.
1.220 + nsCounterList* CounterListFor(const nsSubstring& aCounterName);
1.221 +
1.222 + // Clean up data in any dirty counter lists.
1.223 + void RecalcAll();
1.224 +
1.225 + // Destroy nodes for the frame in any lists, and return whether any
1.226 + // nodes were destroyed.
1.227 + bool DestroyNodesFor(nsIFrame *aFrame);
1.228 +
1.229 + // Clear all data.
1.230 + void Clear() { mNames.Clear(); }
1.231 +
1.232 +#ifdef DEBUG
1.233 + void Dump();
1.234 +#endif
1.235 +
1.236 + static int32_t IncrementCounter(int32_t aOldValue, int32_t aIncrement)
1.237 + {
1.238 + // Addition of unsigned values is defined to be arithmetic
1.239 + // modulo 2^bits (C++ 2011, 3.9.1 [basic.fundamental], clause 4);
1.240 + // addition of signed values is undefined (and clang does
1.241 + // something very strange if we use it here). Likewise integral
1.242 + // conversion from signed to unsigned is also defined as modulo
1.243 + // 2^bits (C++ 2011, 4.7 [conv.integral], clause 2); conversion
1.244 + // from unsigned to signed is however undefined (ibid., clause 3),
1.245 + // but to do what we want we must nonetheless depend on that
1.246 + // small piece of undefined behavior.
1.247 + int32_t newValue = int32_t(uint32_t(aOldValue) + uint32_t(aIncrement));
1.248 + // The CSS Working Group resolved that a counter-increment that
1.249 + // exceeds internal limits should not increment at all.
1.250 + // http://lists.w3.org/Archives/Public/www-style/2013Feb/0392.html
1.251 + // (This means, for example, that if aIncrement is 5, the
1.252 + // counter will get stuck at the largest multiple of 5 less than
1.253 + // the maximum 32-bit integer.)
1.254 + if ((aIncrement > 0) != (newValue > aOldValue)) {
1.255 + newValue = aOldValue;
1.256 + }
1.257 + return newValue;
1.258 + }
1.259 +
1.260 +private:
1.261 + // for |AddCounterResetsAndIncrements| only
1.262 + bool AddResetOrIncrement(nsIFrame *aFrame, int32_t aIndex,
1.263 + const nsStyleCounterData *aCounterData,
1.264 + nsCounterNode::Type aType);
1.265 +
1.266 + nsClassHashtable<nsStringHashKey, nsCounterList> mNames;
1.267 +};
1.268 +
1.269 +#endif /* nsCounterManager_h_ */
