/* -*- 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 {

    mozilla::CounterStylePtr mCounterStyle;

    nsString mSeparator;

    // false for counter(), true for counters()

    bool mAllCounters;

    // args go directly to member variables here and of nsGenConNode

    nsCounterUseNode(nsStyleContentData::CounterFunction* aCounterFunction,

                     uint32_t aContentIndex, bool aAllCounters)

        : nsCounterNode(aContentIndex, USE)

        , mCounterStyle(aCounterFunction->mCounterStyle)

        , mSeparator(aCounterFunction->mSeparator)

        , mAllCounters(aAllCounters)

    {

        NS_ASSERTION(aContentIndex <= INT32_MAX, "out of range");

    }

    virtual bool InitTextFrame(nsGenConList* aList,

            nsIFrame* aPseudoFrame, nsIFrame* aTextFrame) override;

    // 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:

    // 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 nsAString& 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 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_ */