gecko-dev/layout/style/nsHTMLStyleSheet.cpp

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 *
 * ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is mozilla.org code.
 *
 * The Initial Developer of the Original Code is
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 1998
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK *****
 *
 * This Original Code has been modified by IBM Corporation. Modifications made by IBM 
 * described herein are Copyright (c) International Business Machines Corporation, 2000.
 * Modifications to Mozilla code or documentation identified per MPL Section 3.3
 *
 * Date             Modified by     Description of modification
 * 04/20/2000       IBM Corp.      OS/2 VisualAge build.
 */

#include "nsHTMLStyleSheet.h"
#include "nsINameSpaceManager.h"
#include "nsIAtom.h"
#include "nsIURL.h"
#include "nsISupportsArray.h"
#include "nsMappedAttributes.h"
#include "nsILink.h"
#include "nsIFrame.h"
#include "nsStyleContext.h"
#include "nsHTMLAtoms.h"
#include "nsPresContext.h"
#include "nsIEventStateManager.h"
#include "nsIDocument.h"
#include "nsIPresShell.h"
#include "nsStyleConsts.h"
#include "nsIDOMHTMLDocument.h"
#include "nsIDOMHTMLElement.h"
#include "nsCSSAnonBoxes.h"
#include "nsRuleWalker.h"
#include "nsRuleData.h"

nsHTMLStyleSheet::HTMLColorRule::HTMLColorRule(nsHTMLStyleSheet* aSheet)
  : mSheet(aSheet)
{
}

nsHTMLStyleSheet::HTMLColorRule::~HTMLColorRule()
{
}

NS_IMPL_ISUPPORTS1(nsHTMLStyleSheet::HTMLColorRule, nsIStyleRule)

NS_IMETHODIMP
nsHTMLStyleSheet::HTMLColorRule::GetStyleSheet(nsIStyleSheet*& aSheet) const
{
  NS_IF_ADDREF(mSheet);
  aSheet = mSheet;
  return NS_OK;
}

NS_IMETHODIMP
nsHTMLStyleSheet::HTMLColorRule::MapRuleInfoInto(nsRuleData* aRuleData)
{
  if (aRuleData->mSID == eStyleStruct_Color) {
    if (aRuleData->mColorData->mColor.GetUnit() == eCSSUnit_Null)
      aRuleData->mColorData->mColor = nsCSSValue(mColor);
  }
  return NS_OK;
}

#ifdef DEBUG
NS_IMETHODIMP
nsHTMLStyleSheet::HTMLColorRule::List(FILE* out, PRInt32 aIndent) const
{
  return NS_OK;
}
#endif

nsHTMLStyleSheet::GenericTableRule::GenericTableRule(nsHTMLStyleSheet* aSheet)
{
  mSheet = aSheet;
}

nsHTMLStyleSheet::GenericTableRule::~GenericTableRule()
{
}

NS_IMPL_ISUPPORTS1(nsHTMLStyleSheet::GenericTableRule, nsIStyleRule)

NS_IMETHODIMP
nsHTMLStyleSheet::GenericTableRule::GetStyleSheet(nsIStyleSheet*& aSheet) const
{
  aSheet = mSheet;
  return NS_OK;
}

NS_IMETHODIMP
nsHTMLStyleSheet::GenericTableRule::MapRuleInfoInto(nsRuleData* aRuleData)
{
  // Nothing to do.
  return NS_OK;
}

#ifdef DEBUG
NS_IMETHODIMP
nsHTMLStyleSheet::GenericTableRule::List(FILE* out, PRInt32 aIndent) const
{
  return NS_OK;
}
#endif

nsHTMLStyleSheet::TableTHRule::TableTHRule(nsHTMLStyleSheet* aSheet)
: GenericTableRule(aSheet)
{
}

nsHTMLStyleSheet::TableTHRule::~TableTHRule()
{
}

static void PostResolveCallback(nsStyleStruct* aStyleStruct, nsRuleData* aRuleData)
{
  nsStyleText* text = (nsStyleText*)aStyleStruct;
  if (text->mTextAlign == NS_STYLE_TEXT_ALIGN_DEFAULT) {
    nsStyleContext* parentContext = aRuleData->mStyleContext->GetParent();

    if (parentContext) {
      const nsStyleText* parentStyleText = parentContext->GetStyleText();
      PRUint8 parentAlign = parentStyleText->mTextAlign;
      text->mTextAlign = (NS_STYLE_TEXT_ALIGN_DEFAULT == parentAlign)
                              ? NS_STYLE_TEXT_ALIGN_CENTER : parentAlign;
    }
  }
}

NS_IMETHODIMP
nsHTMLStyleSheet::TableTHRule::MapRuleInfoInto(nsRuleData* aRuleData)
{
  if (aRuleData && aRuleData->mSID == eStyleStruct_Text) {
    aRuleData->mCanStoreInRuleTree = PR_FALSE;
    aRuleData->mPostResolveCallback = &PostResolveCallback;
  }
  return NS_OK;
}

static void 
ProcessTableRulesAttribute(nsStyleStruct* aStyleStruct, 
                           nsRuleData*    aRuleData,
                           PRUint8        aSide,
                           PRBool         aGroup,
                           PRUint8        aRulesArg1,
                           PRUint8        aRulesArg2,
                           PRUint8        aRulesArg3)
{
  if (!aStyleStruct || !aRuleData || !aRuleData->mPresContext) return;

  nsStyleContext* tableContext = aRuleData->mStyleContext->GetParent();
  if (!tableContext)
    return;
  if (!aGroup) {
    tableContext = tableContext->GetParent();
    if (!tableContext)
      return;
  } 
  
  const nsStyleTable* tableData = tableContext->GetStyleTable();
  if (aRulesArg1 == tableData->mRules ||
      aRulesArg2 == tableData->mRules ||
      aRulesArg3 == tableData->mRules) {
    const nsStyleBorder* tableBorderData = tableContext->GetStyleBorder();
    PRUint8 tableBorderStyle = tableBorderData->GetBorderStyle(aSide);

    nsStyleBorder* borderData = (nsStyleBorder*)aStyleStruct;
    if (!borderData)
      return;
    PRUint8 borderStyle = borderData->GetBorderStyle(aSide);
    // XXX It appears that the style system erronously applies the custom style rule after css style, 
    // consequently it does not properly fit into the casade. For now, assume that a border style of none
    // implies that the style has not been set.
    // XXXldb No, there's nothing wrong with the style system.  The problem
    // is that the author of all these table rules made them work as
    // post-resolve callbacks, which is an override mechanism that was meant
    // to be used for other things.  They should instead map their rule data
    // normally (see nsIStyleRule.h).
    if (NS_STYLE_BORDER_STYLE_NONE == borderStyle) {
      // use the table's border style if it is dashed or dotted, otherwise use solid
      PRUint8 bStyle = ((NS_STYLE_BORDER_STYLE_NONE != tableBorderStyle) &&
                        (NS_STYLE_BORDER_STYLE_HIDDEN != tableBorderStyle)) 
                        ? tableBorderStyle : NS_STYLE_BORDER_STYLE_SOLID;
      if ((NS_STYLE_BORDER_STYLE_DASHED != bStyle) && 
          (NS_STYLE_BORDER_STYLE_DOTTED != bStyle) && 
          (NS_STYLE_BORDER_STYLE_SOLID  != bStyle)) {
        bStyle = NS_STYLE_BORDER_STYLE_SOLID;
      }
      bStyle |= NS_STYLE_BORDER_STYLE_RULES_MASK;
      borderData->SetBorderStyle(aSide, bStyle);

      nscolor borderColor;
      PRBool transparent, foreground;
      borderData->GetBorderColor(aSide, borderColor, transparent, foreground);
      if (transparent || foreground) {
        // use the table's border color if it is set, otherwise use black
        nscolor tableBorderColor;
        tableBorderData->GetBorderColor(aSide, tableBorderColor, transparent, foreground);
        borderColor = (transparent || foreground) ? NS_RGB(0,0,0) : tableBorderColor;
        borderData->SetBorderColor(aSide, borderColor);
      }
      // set the border width to be 1 pixel
      nscoord onePixel =
        NSToCoordRound(aRuleData->mPresContext->ScaledPixelsToTwips());
      nsStyleCoord coord(onePixel);
      switch(aSide) {
      case NS_SIDE_TOP:
        borderData->mBorder.SetTop(coord);
        break;
      case NS_SIDE_RIGHT:
        borderData->mBorder.SetRight(coord);
        break;
      case NS_SIDE_BOTTOM:
        borderData->mBorder.SetBottom(coord);
        break;
      default: // NS_SIDE_LEFT
        borderData->mBorder.SetLeft(coord);
        break;
      }
    }
  }
}

nsHTMLStyleSheet::TableTbodyRule::TableTbodyRule(nsHTMLStyleSheet* aSheet)
: GenericTableRule(aSheet)
{
}

nsHTMLStyleSheet::TableTbodyRule::~TableTbodyRule()
{
}

static void TbodyPostResolveCallback(nsStyleStruct* aStyleStruct, nsRuleData* aRuleData)
{
  ::ProcessTableRulesAttribute(aStyleStruct, aRuleData, NS_SIDE_TOP, PR_TRUE, NS_STYLE_TABLE_RULES_ALL,
                               NS_STYLE_TABLE_RULES_GROUPS, NS_STYLE_TABLE_RULES_ROWS);
  ::ProcessTableRulesAttribute(aStyleStruct, aRuleData, NS_SIDE_BOTTOM, PR_TRUE, NS_STYLE_TABLE_RULES_ALL,
                               NS_STYLE_TABLE_RULES_GROUPS, NS_STYLE_TABLE_RULES_ROWS);
}

NS_IMETHODIMP
nsHTMLStyleSheet::TableTbodyRule::MapRuleInfoInto(nsRuleData* aRuleData)
{
  if (aRuleData && aRuleData->mSID == eStyleStruct_Border) {
    aRuleData->mCanStoreInRuleTree = PR_FALSE;
    aRuleData->mPostResolveCallback = &TbodyPostResolveCallback;
  }
  return NS_OK;
}
// -----------------------------------------------------------

nsHTMLStyleSheet::TableRowRule::TableRowRule(nsHTMLStyleSheet* aSheet)
: GenericTableRule(aSheet)
{
}

nsHTMLStyleSheet::TableRowRule::~TableRowRule()
{
}

static void RowPostResolveCallback(nsStyleStruct* aStyleStruct, nsRuleData* aRuleData)
{
  ::ProcessTableRulesAttribute(aStyleStruct, aRuleData, NS_SIDE_TOP, PR_FALSE, NS_STYLE_TABLE_RULES_ALL,
                               NS_STYLE_TABLE_RULES_ROWS, NS_STYLE_TABLE_RULES_ROWS);
  ::ProcessTableRulesAttribute(aStyleStruct, aRuleData, NS_SIDE_BOTTOM, PR_FALSE, NS_STYLE_TABLE_RULES_ALL,
                               NS_STYLE_TABLE_RULES_ROWS, NS_STYLE_TABLE_RULES_ROWS);
}

NS_IMETHODIMP
nsHTMLStyleSheet::TableRowRule::MapRuleInfoInto(nsRuleData* aRuleData)
{
  if (aRuleData && aRuleData->mSID == eStyleStruct_Border) {
    aRuleData->mCanStoreInRuleTree = PR_FALSE;
    aRuleData->mPostResolveCallback = &RowPostResolveCallback;
  }
  return NS_OK;
}

nsHTMLStyleSheet::TableColgroupRule::TableColgroupRule(nsHTMLStyleSheet* aSheet)
: GenericTableRule(aSheet)
{
}

nsHTMLStyleSheet::TableColgroupRule::~TableColgroupRule()
{
}

static void ColgroupPostResolveCallback(nsStyleStruct* aStyleStruct, nsRuleData* aRuleData)
{
  ::ProcessTableRulesAttribute(aStyleStruct, aRuleData, NS_SIDE_LEFT, PR_TRUE, NS_STYLE_TABLE_RULES_ALL,
                               NS_STYLE_TABLE_RULES_GROUPS, NS_STYLE_TABLE_RULES_COLS);
  ::ProcessTableRulesAttribute(aStyleStruct, aRuleData, NS_SIDE_RIGHT, PR_TRUE, NS_STYLE_TABLE_RULES_ALL,
                               NS_STYLE_TABLE_RULES_GROUPS, NS_STYLE_TABLE_RULES_COLS);
}

NS_IMETHODIMP
nsHTMLStyleSheet::TableColgroupRule::MapRuleInfoInto(nsRuleData* aRuleData)
{
  if (aRuleData && aRuleData->mSID == eStyleStruct_Border) {
    aRuleData->mCanStoreInRuleTree = PR_FALSE;
    aRuleData->mPostResolveCallback = &ColgroupPostResolveCallback;
  }
  return NS_OK;
}

nsHTMLStyleSheet::TableColRule::TableColRule(nsHTMLStyleSheet* aSheet)
: GenericTableRule(aSheet)
{
}

nsHTMLStyleSheet::TableColRule::~TableColRule()
{
}

static void ColPostResolveCallback(nsStyleStruct* aStyleStruct, nsRuleData* aRuleData)
{
  ::ProcessTableRulesAttribute(aStyleStruct, aRuleData, NS_SIDE_LEFT, PR_FALSE, NS_STYLE_TABLE_RULES_ALL,
                               NS_STYLE_TABLE_RULES_COLS, NS_STYLE_TABLE_RULES_COLS);
  ::ProcessTableRulesAttribute(aStyleStruct, aRuleData, NS_SIDE_RIGHT, PR_FALSE, NS_STYLE_TABLE_RULES_ALL,
                               NS_STYLE_TABLE_RULES_COLS, NS_STYLE_TABLE_RULES_COLS);
}

NS_IMETHODIMP
nsHTMLStyleSheet::TableColRule::MapRuleInfoInto(nsRuleData* aRuleData)
{
  if (aRuleData && aRuleData->mSID == eStyleStruct_Border) {
    aRuleData->mCanStoreInRuleTree = PR_FALSE;
    aRuleData->mPostResolveCallback = &ColPostResolveCallback;
  }
  return NS_OK;
}
// -----------------------------------------------------------

struct MappedAttrTableEntry : public PLDHashEntryHdr {
  nsMappedAttributes *mAttributes;
};

PR_STATIC_CALLBACK(PLDHashNumber)
MappedAttrTable_HashKey(PLDHashTable *table, const void *key)
{
  nsMappedAttributes *attributes =
    NS_STATIC_CAST(nsMappedAttributes*, NS_CONST_CAST(void*, key));

  return attributes->HashValue();
}

PR_STATIC_CALLBACK(void)
MappedAttrTable_ClearEntry(PLDHashTable *table, PLDHashEntryHdr *hdr)
{
  MappedAttrTableEntry *entry = NS_STATIC_CAST(MappedAttrTableEntry*, hdr);

  entry->mAttributes->DropStyleSheetReference();
  memset(entry, 0, sizeof(MappedAttrTableEntry));
}

PR_STATIC_CALLBACK(PRBool)
MappedAttrTable_MatchEntry(PLDHashTable *table, const PLDHashEntryHdr *hdr,
                           const void *key)
{
  nsMappedAttributes *attributes =
    NS_STATIC_CAST(nsMappedAttributes*, NS_CONST_CAST(void*, key));
  const MappedAttrTableEntry *entry =
    NS_STATIC_CAST(const MappedAttrTableEntry*, hdr);

  return attributes->Equals(entry->mAttributes);
}

static PLDHashTableOps MappedAttrTable_Ops = {
  PL_DHashAllocTable,
  PL_DHashFreeTable,
  PL_DHashGetKeyStub,
  MappedAttrTable_HashKey,
  MappedAttrTable_MatchEntry,
  PL_DHashMoveEntryStub,
  MappedAttrTable_ClearEntry,
  PL_DHashFinalizeStub,
  NULL
};

// -----------------------------------------------------------

nsHTMLStyleSheet::nsHTMLStyleSheet(void)
  : mURL(nsnull),
    mDocument(nsnull),
    mLinkRule(nsnull),
    mVisitedRule(nsnull),
    mActiveRule(nsnull),
    mDocumentColorRule(nsnull)
{
  mMappedAttrTable.ops = nsnull;
}

nsresult
nsHTMLStyleSheet::Init()
{
  mTableTbodyRule = new TableTbodyRule(this);
  if (!mTableTbodyRule)
    return NS_ERROR_OUT_OF_MEMORY;
  NS_ADDREF(mTableTbodyRule);

  mTableRowRule = new TableRowRule(this);
  if (!mTableRowRule)
    return NS_ERROR_OUT_OF_MEMORY;
  NS_ADDREF(mTableRowRule);

  mTableColgroupRule = new TableColgroupRule(this);
  if (!mTableColgroupRule)
    return NS_ERROR_OUT_OF_MEMORY;
  NS_ADDREF(mTableColgroupRule);

  mTableColRule = new TableColRule(this);
  if (!mTableColRule)
    return NS_ERROR_OUT_OF_MEMORY;
  NS_ADDREF(mTableColRule);

  mTableTHRule = new TableTHRule(this);
  if (!mTableTHRule)
    return NS_ERROR_OUT_OF_MEMORY;
  NS_ADDREF(mTableTHRule);

  return NS_OK;
}

nsHTMLStyleSheet::~nsHTMLStyleSheet()
{
  NS_IF_RELEASE(mURL);
  if (nsnull != mLinkRule) {
    mLinkRule->mSheet = nsnull;
    NS_RELEASE(mLinkRule);
  }
  if (nsnull != mVisitedRule) {
    mVisitedRule->mSheet = nsnull;
    NS_RELEASE(mVisitedRule);
  }
  if (nsnull != mActiveRule) {
    mActiveRule->mSheet = nsnull;
    NS_RELEASE(mActiveRule);
  }
  if (nsnull != mDocumentColorRule) {
    mDocumentColorRule->mSheet = nsnull;
    NS_RELEASE(mDocumentColorRule);
  }
  if (nsnull != mTableTbodyRule) {
    mTableTbodyRule->mSheet = nsnull;
    NS_RELEASE(mTableTbodyRule);
  }
  if (nsnull != mTableRowRule) {
    mTableRowRule->mSheet = nsnull;
    NS_RELEASE(mTableRowRule);
  }
  if (nsnull != mTableColgroupRule) {
    mTableColgroupRule->mSheet = nsnull;
    NS_RELEASE(mTableColgroupRule);
  }
  if (nsnull != mTableColRule) {
    mTableColRule->mSheet = nsnull;
    NS_RELEASE(mTableColRule);
  }
  if (nsnull != mTableTHRule) {
    mTableTHRule->mSheet = nsnull;
    NS_RELEASE(mTableTHRule);
  }
  if (mMappedAttrTable.ops)
    PL_DHashTableFinish(&mMappedAttrTable);
}

NS_IMPL_ISUPPORTS2(nsHTMLStyleSheet, nsIStyleSheet, nsIStyleRuleProcessor)

static nsresult GetBodyColor(nsPresContext* aPresContext, nscolor* aColor)
{
  nsIPresShell *shell = aPresContext->PresShell();
  nsCOMPtr<nsIDOMHTMLDocument> domdoc = do_QueryInterface(shell->GetDocument());
  if (!domdoc)
    return NS_ERROR_FAILURE;
  nsCOMPtr<nsIDOMHTMLElement> body;
  domdoc->GetBody(getter_AddRefs(body));
  nsCOMPtr<nsIContent> bodyContent = do_QueryInterface(body);
  nsIFrame *bodyFrame;
  shell->GetPrimaryFrameFor(bodyContent, &bodyFrame);
  if (!bodyFrame)
    return NS_ERROR_FAILURE;
  *aColor = bodyFrame->GetStyleColor()->mColor;
  return NS_OK;
}

NS_IMETHODIMP
nsHTMLStyleSheet::RulesMatching(ElementRuleProcessorData* aData)
{
  nsIStyledContent *styledContent = aData->mStyledContent;

  if (styledContent) {
    nsRuleWalker *ruleWalker = aData->mRuleWalker;
    if (aData->mIsHTMLContent) {
      nsIAtom* tag = aData->mContentTag;

      // if we have anchor colors, check if this is an anchor with an href
      if (tag == nsHTMLAtoms::a) {
        if (mLinkRule || mVisitedRule || mActiveRule) {
          if (aData->mIsHTMLLink) {
            switch (aData->mLinkState) {
              case eLinkState_Unvisited:
                if (mLinkRule)
                  ruleWalker->Forward(mLinkRule);
                break;
              case eLinkState_Visited:
                if (mVisitedRule)
                  ruleWalker->Forward(mVisitedRule);
                break;
              default:
                break;
            }

            // No need to add to the active rule if it's not a link
            if (mActiveRule && (aData->mEventState & NS_EVENT_STATE_ACTIVE))
              ruleWalker->Forward(mActiveRule);
          }
        } // end link/visited/active rules
      } // end A tag
      // add the rule to handle text-align for a <th>
      else if (tag == nsHTMLAtoms::th) {
        ruleWalker->Forward(mTableTHRule);
      }
      else if (tag == nsHTMLAtoms::tr) {
        ruleWalker->Forward(mTableRowRule);
      }
      else if ((tag == nsHTMLAtoms::thead) || (tag == nsHTMLAtoms::tbody) || (tag == nsHTMLAtoms::tfoot)) {
        ruleWalker->Forward(mTableTbodyRule);
      }
      else if (tag == nsHTMLAtoms::col) {
        ruleWalker->Forward(mTableColRule);
      }
      else if (tag == nsHTMLAtoms::colgroup) {
        ruleWalker->Forward(mTableColgroupRule);
      }
      else if (tag == nsHTMLAtoms::table) {
        if (aData->mCompatMode == eCompatibility_NavQuirks) {
          nscolor bodyColor;
          nsresult rv =
            GetBodyColor(ruleWalker->GetCurrentNode()->GetPresContext(),
                         &bodyColor);
          if (NS_SUCCEEDED(rv) &&
              (!mDocumentColorRule || bodyColor != mDocumentColorRule->mColor)) {
            if (mDocumentColorRule) {
              mDocumentColorRule->mSheet = nsnull;
              NS_RELEASE(mDocumentColorRule);
            }
            mDocumentColorRule = new HTMLColorRule(this);
            if (mDocumentColorRule) {
              NS_ADDREF(mDocumentColorRule);
              mDocumentColorRule->mColor = bodyColor;
            }
          }
          if (mDocumentColorRule)
            ruleWalker->Forward(mDocumentColorRule);
        }
      }
    } // end html element

    // just get the style rules from the content
    styledContent->WalkContentStyleRules(ruleWalker);
  }

  return NS_OK;
}

// Test if style is dependent on content state
NS_IMETHODIMP
nsHTMLStyleSheet::HasStateDependentStyle(StateRuleProcessorData* aData,
                                         nsReStyleHint* aResult)
{
  if (mActiveRule &&
      (aData->mStateMask & NS_EVENT_STATE_ACTIVE) &&
      aData->mStyledContent &&
      aData->mIsHTMLContent &&
      aData->mIsHTMLLink &&
      aData->mContentTag == nsHTMLAtoms::a)
    *aResult = eReStyle_Self;
  else
    *aResult = nsReStyleHint(0);

  return NS_OK;
}

NS_IMETHODIMP
nsHTMLStyleSheet::HasAttributeDependentStyle(AttributeRuleProcessorData* aData,
                                             nsReStyleHint* aResult)
{
  // Result is true for |href| changes on HTML links if we have link rules.
  nsIStyledContent *styledContent = aData->mStyledContent;
  if (aData->mAttribute == nsHTMLAtoms::href &&
      (mLinkRule || mVisitedRule || mActiveRule) &&
      styledContent &&
      styledContent->IsContentOfType(nsIContent::eHTML) &&
      aData->mContentTag == nsHTMLAtoms::a) {
    *aResult = eReStyle_Self;
    return NS_OK;
  }

  // Don't worry about the mDocumentColorRule since it only applies
  // to descendants of body, when we're already reresolving.

  // Handle the content style rules.
  if (styledContent && styledContent->IsAttributeMapped(aData->mAttribute)) {
    *aResult = eReStyle_Self;
    return NS_OK;
  }

  *aResult = nsReStyleHint(0);
  return NS_OK;
}


NS_IMETHODIMP
nsHTMLStyleSheet::RulesMatching(PseudoRuleProcessorData* aData)
{
  nsIAtom* pseudoTag = aData->mPseudoTag;
  if (pseudoTag == nsCSSAnonBoxes::tableCol) {
    nsRuleWalker *ruleWalker = aData->mRuleWalker;
    if (ruleWalker) {
      ruleWalker->Forward(mTableColRule);
    }
  }
  return NS_OK;
}


  // nsIStyleSheet api
NS_IMETHODIMP
nsHTMLStyleSheet::GetURL(nsIURI*& aURL) const
{
  aURL = mURL;
  NS_IF_ADDREF(aURL);
  return NS_OK;
}

NS_IMETHODIMP
nsHTMLStyleSheet::GetTitle(nsString& aTitle) const
{
  aTitle.Truncate();
  return NS_OK;
}

NS_IMETHODIMP
nsHTMLStyleSheet::GetType(nsString& aType) const
{
  aType.AssignLiteral("text/html");
  return NS_OK;
}

NS_IMETHODIMP
nsHTMLStyleSheet::GetMediumCount(PRInt32& aCount) const
{
  aCount = 0;
  return NS_OK;
}

NS_IMETHODIMP
nsHTMLStyleSheet::GetMediumAt(PRInt32 aIndex, nsIAtom*& aMedium) const
{
  aMedium = nsnull;
  return NS_ERROR_INVALID_ARG;
}

NS_IMETHODIMP_(PRBool)
nsHTMLStyleSheet::UseForMedium(nsIAtom* aMedium) const
{
  return PR_TRUE; // works for all media
}

NS_IMETHODIMP_(PRBool)
nsHTMLStyleSheet::HasRules() const
{
  return PR_TRUE; // We have rules at all reasonable times
}

NS_IMETHODIMP
nsHTMLStyleSheet::GetApplicable(PRBool& aApplicable) const
{
  aApplicable = PR_TRUE;
  return NS_OK;
}

NS_IMETHODIMP
nsHTMLStyleSheet::SetEnabled(PRBool aEnabled)
{ // these can't be disabled
  return NS_OK;
}

NS_IMETHODIMP
nsHTMLStyleSheet::GetComplete(PRBool& aComplete) const
{
  aComplete = PR_TRUE;
  return NS_OK;
}

NS_IMETHODIMP
nsHTMLStyleSheet::SetComplete()
{
  return NS_OK;
}

NS_IMETHODIMP
nsHTMLStyleSheet::GetParentSheet(nsIStyleSheet*& aParent) const
{
  aParent = nsnull;
  return NS_OK;
}

NS_IMETHODIMP
nsHTMLStyleSheet::GetOwningDocument(nsIDocument*& aDocument) const
{
  aDocument = mDocument;
  NS_IF_ADDREF(aDocument);
  return NS_OK;
}

NS_IMETHODIMP
nsHTMLStyleSheet::SetOwningDocument(nsIDocument* aDocument)
{
  mDocument = aDocument; // not refcounted
  return NS_OK;
}

nsresult
nsHTMLStyleSheet::Init(nsIURI* aURL, nsIDocument* aDocument)
{
  NS_PRECONDITION(aURL && aDocument, "null ptr");
  if (! aURL || ! aDocument)
    return NS_ERROR_NULL_POINTER;

  if (mURL || mDocument)
    return NS_ERROR_ALREADY_INITIALIZED;

  mDocument = aDocument; // not refcounted!
  mURL = aURL;
  NS_ADDREF(mURL);
  return NS_OK;
}

nsresult
nsHTMLStyleSheet::Reset(nsIURI* aURL)
{
  NS_IF_RELEASE(mURL);
  mURL = aURL;
  NS_ADDREF(mURL);

  if (mLinkRule) {
    mLinkRule->mSheet = nsnull;
    NS_RELEASE(mLinkRule);
  }
  if (mVisitedRule) {
    mVisitedRule->mSheet = nsnull;
    NS_RELEASE(mVisitedRule);
  }
  if (mActiveRule) {
    mActiveRule->mSheet = nsnull;
    NS_RELEASE(mActiveRule);
  }
  if (mDocumentColorRule) {
    mDocumentColorRule->mSheet = nsnull;
    NS_RELEASE(mDocumentColorRule);
  }

  if (mMappedAttrTable.ops) {
    PL_DHashTableFinish(&mMappedAttrTable);
    mMappedAttrTable.ops = nsnull;
  }

  return NS_OK;
}

nsresult
nsHTMLStyleSheet::GetLinkColor(nscolor& aColor)
{
  if (!mLinkRule) {
    return NS_HTML_STYLE_PROPERTY_NOT_THERE;
  }
  else {
    aColor = mLinkRule->mColor;
    return NS_OK;
  }
}

nsresult
nsHTMLStyleSheet::GetActiveLinkColor(nscolor& aColor)
{
  if (!mActiveRule) {
    return NS_HTML_STYLE_PROPERTY_NOT_THERE;
  }
  else {
    aColor = mActiveRule->mColor;
    return NS_OK;
  }
}

nsresult
nsHTMLStyleSheet::GetVisitedLinkColor(nscolor& aColor)
{
  if (!mVisitedRule) {
    return NS_HTML_STYLE_PROPERTY_NOT_THERE;
  }
  else {
    aColor = mVisitedRule->mColor;
    return NS_OK;
  }
}

nsresult
nsHTMLStyleSheet::SetLinkColor(nscolor aColor)
{
  if (mLinkRule) {
    if (mLinkRule->mColor == aColor)
      return NS_OK;
    mLinkRule->mSheet = nsnull;
    NS_RELEASE(mLinkRule);
  }

  mLinkRule = new HTMLColorRule(this);
  if (!mLinkRule)
    return NS_ERROR_OUT_OF_MEMORY;
  NS_ADDREF(mLinkRule);

  mLinkRule->mColor = aColor;
  return NS_OK;
}


nsresult
nsHTMLStyleSheet::SetActiveLinkColor(nscolor aColor)
{
  if (mActiveRule) {
    if (mActiveRule->mColor == aColor)
      return NS_OK;
    mActiveRule->mSheet = nsnull;
    NS_RELEASE(mActiveRule);
  }

  mActiveRule = new HTMLColorRule(this);
  if (!mActiveRule)
    return NS_ERROR_OUT_OF_MEMORY;
  NS_ADDREF(mActiveRule);

  mActiveRule->mColor = aColor;
  return NS_OK;
}

nsresult
nsHTMLStyleSheet::SetVisitedLinkColor(nscolor aColor)
{
  if (mVisitedRule) {
    if (mVisitedRule->mColor == aColor)
      return NS_OK;
    mVisitedRule->mSheet = nsnull;
    NS_RELEASE(mVisitedRule);
  }

  mVisitedRule = new HTMLColorRule(this);
  if (!mVisitedRule)
    return NS_ERROR_OUT_OF_MEMORY;
  NS_ADDREF(mVisitedRule);

  mVisitedRule->mColor = aColor;
  return NS_OK;
}

already_AddRefed<nsMappedAttributes>
nsHTMLStyleSheet::UniqueMappedAttributes(nsMappedAttributes* aMapped)
{
  if (!mMappedAttrTable.ops) {
    PRBool res = PL_DHashTableInit(&mMappedAttrTable, &MappedAttrTable_Ops,
                                   nsnull, sizeof(MappedAttrTableEntry), 16);
    if (!res) {
      mMappedAttrTable.ops = nsnull;
      return nsnull;
    }
  }
  MappedAttrTableEntry *entry = NS_STATIC_CAST(MappedAttrTableEntry*,
    PL_DHashTableOperate(&mMappedAttrTable, aMapped, PL_DHASH_ADD));
  if (!entry)
    return nsnull;
  if (!entry->mAttributes) {
    // We added a new entry to the hashtable, so we have a new unique set.
    entry->mAttributes = aMapped;
  }
  NS_ADDREF(entry->mAttributes); // for caller
  return entry->mAttributes;
}

void
nsHTMLStyleSheet::DropMappedAttributes(nsMappedAttributes* aMapped)
{
  NS_ENSURE_TRUE(aMapped, /**/);

  NS_ASSERTION(mMappedAttrTable.ops, "table uninitialized");
#ifdef DEBUG
  PRUint32 entryCount = mMappedAttrTable.entryCount - 1;
#endif

  PL_DHashTableOperate(&mMappedAttrTable, aMapped, PL_DHASH_REMOVE);

  NS_ASSERTION(entryCount == mMappedAttrTable.entryCount, "not removed");
}

#ifdef DEBUG
void nsHTMLStyleSheet::List(FILE* out, PRInt32 aIndent) const
{
  // Indent
  for (PRInt32 index = aIndent; --index >= 0; ) fputs("  ", out);

  fputs("HTML Style Sheet: ", out);
  nsCAutoString urlSpec;
  mURL->GetSpec(urlSpec);
  if (!urlSpec.IsEmpty()) {
    fputs(urlSpec.get(), out);
  }
  fputs("\n", out);
}
#endif

// XXX For convenience and backwards compatibility
nsresult
NS_NewHTMLStyleSheet(nsHTMLStyleSheet** aInstancePtrResult, nsIURI* aURL, 
                     nsIDocument* aDocument)
{
  nsresult rv;
  nsHTMLStyleSheet* sheet;
  if (NS_FAILED(rv = NS_NewHTMLStyleSheet(&sheet)))
    return rv;

  if (NS_FAILED(rv = sheet->Init(aURL, aDocument))) {
    NS_RELEASE(sheet);
    return rv;
  }

  *aInstancePtrResult = sheet;
  return NS_OK;
}


nsresult
NS_NewHTMLStyleSheet(nsHTMLStyleSheet** aInstancePtrResult)
{
  NS_ASSERTION(aInstancePtrResult, "null out param");

  nsHTMLStyleSheet *it = new nsHTMLStyleSheet();
  if (!it) {
    *aInstancePtrResult = nsnull;
    return NS_ERROR_OUT_OF_MEMORY;
  }

  NS_ADDREF(it);
  nsresult rv = it->Init();
  if (NS_FAILED(rv))
    NS_RELEASE(it);

  *aInstancePtrResult = it; // NS_ADDREF above, or set to null by NS_RELEASE
  return rv;
}