layout/generic/nsSplittableFrame.cpp

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* ***** BEGIN LICENSE BLOCK *****
   3  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
   4  *
   5  * The contents of this file are subject to the Mozilla Public License Version
   6  * 1.1 (the "License"); you may not use this file except in compliance with
   7  * the License. You may obtain a copy of the License at
   8  * http://www.mozilla.org/MPL/
   9  *
  10  * Software distributed under the License is distributed on an "AS IS" basis,
  11  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  12  * for the specific language governing rights and limitations under the
  13  * License.
  14  *
  15  * The Original Code is mozilla.org code.
  16  *
  17  * The Initial Developer of the Original Code is
  18  * Netscape Communications Corporation.
  19  * Portions created by the Initial Developer are Copyright (C) 1998
  20  * the Initial Developer. All Rights Reserved.
  21  *
  22  * Contributor(s):
  23  *
  24  * Alternatively, the contents of this file may be used under the terms of
  25  * either of the GNU General Public License Version 2 or later (the "GPL"),
  26  * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
  27  * in which case the provisions of the GPL or the LGPL are applicable instead
  28  * of those above. If you wish to allow use of your version of this file only
  29  * under the terms of either the GPL or the LGPL, and not to allow others to
  30  * use your version of this file under the terms of the MPL, indicate your
  31  * decision by deleting the provisions above and replace them with the notice
  32  * and other provisions required by the GPL or the LGPL. If you do not delete
  33  * the provisions above, a recipient may use your version of this file under
  34  * the terms of any one of the MPL, the GPL or the LGPL.
  35  *
  36  * ***** END LICENSE BLOCK ***** */
  37
  38 /*
  39  * base class for rendering objects that can be split across lines,
  40  * columns, or pages
  41  */
  42
  43 #include "nsSplittableFrame.h"
  44 #include "nsIContent.h"
  45 #include "nsPresContext.h"
  46 #include "nsStyleContext.h"
  47
  48 NS_IMETHODIMP
  49 nsSplittableFrame::Init(nsIContent*      aContent,
  50                         nsIFrame*        aParent,
  51                         nsIFrame*        aPrevInFlow)
  52 {
  53   nsresult rv = nsFrame::Init(aContent, aParent, aPrevInFlow);
  54
  55   if (aPrevInFlow) {
  56     // Hook the frame into the flow
  57     SetPrevInFlow(aPrevInFlow);
  58     aPrevInFlow->SetNextInFlow(this);
  59   }
  60
  61   return rv;
  62 }
  63
  64 void
  65 nsSplittableFrame::Destroy()
  66 {
  67   // Disconnect from the flow list
  68   if (mPrevContinuation || mNextContinuation) {
  69     RemoveFromFlow(this);
  70   }
  71
  72   // Let the base class destroy the frame
  73   nsFrame::Destroy();
  74 }
  75
  76 nsSplittableType
  77 nsSplittableFrame::GetSplittableType() const
  78 {
  79   return NS_FRAME_SPLITTABLE;
  80 }
  81
  82 nsIFrame* nsSplittableFrame::GetPrevContinuation() const
  83 {
  84   return mPrevContinuation;
  85 }
  86
  87 NS_METHOD nsSplittableFrame::SetPrevContinuation(nsIFrame* aFrame)
  88 {
  89   NS_ASSERTION (!aFrame || GetType() == aFrame->GetType(), "setting a prev continuation with incorrect type!");
  90   NS_ASSERTION (!IsInPrevContinuationChain(aFrame, this), "creating a loop in continuation chain!");
  91   mPrevContinuation = aFrame;
  92   RemoveStateBits(NS_FRAME_IS_FLUID_CONTINUATION);
  93   return NS_OK;
  94 }
  95
  96 nsIFrame* nsSplittableFrame::GetNextContinuation() const
  97 {
  98   return mNextContinuation;
  99 }
 100
 101 NS_METHOD nsSplittableFrame::SetNextContinuation(nsIFrame* aFrame)
 102 {
 103   NS_ASSERTION (!aFrame || GetType() == aFrame->GetType(),  "setting a next continuation with incorrect type!");
 104   NS_ASSERTION (!IsInNextContinuationChain(aFrame, this), "creating a loop in continuation chain!");
 105   mNextContinuation = aFrame;
 106   if (aFrame)
 107     aFrame->RemoveStateBits(NS_FRAME_IS_FLUID_CONTINUATION);
 108   return NS_OK;
 109 }
 110
 111 nsIFrame* nsSplittableFrame::GetFirstContinuation() const
 112 {
 113   nsSplittableFrame* firstContinuation = const_cast<nsSplittableFrame*>(this);
 114   while (firstContinuation->mPrevContinuation)  {
 115     firstContinuation = static_cast<nsSplittableFrame*>(firstContinuation->mPrevContinuation);
 116   }
 117   NS_POSTCONDITION(firstContinuation, "illegal state in continuation chain.");
 118   return firstContinuation;
 119 }
 120
 121 nsIFrame* nsSplittableFrame::GetLastContinuation() const
 122 {
 123   nsSplittableFrame* lastContinuation = const_cast<nsSplittableFrame*>(this);
 124   while (lastContinuation->mNextContinuation)  {
 125     lastContinuation = static_cast<nsSplittableFrame*>(lastContinuation->mNextContinuation);
 126   }
 127   NS_POSTCONDITION(lastContinuation, "illegal state in continuation chain.");
 128   return lastContinuation;
 129 }
 130
 131 #ifdef DEBUG
 132 PRBool nsSplittableFrame::IsInPrevContinuationChain(nsIFrame* aFrame1, nsIFrame* aFrame2)
 133 {
 134   while (aFrame1) {
 135     if (aFrame1 == aFrame2)
 136       return PR_TRUE;
 137     aFrame1 = aFrame1->GetPrevContinuation();
 138   }
 139   return PR_FALSE;
 140 }
 141
 142 PRBool nsSplittableFrame::IsInNextContinuationChain(nsIFrame* aFrame1, nsIFrame* aFrame2)
 143 {
 144   while (aFrame1) {
 145     if (aFrame1 == aFrame2)
 146       return PR_TRUE;
 147     aFrame1 = aFrame1->GetNextContinuation();
 148   }
 149   return PR_FALSE;
 150 }
 151 #endif
 152
 153 nsIFrame* nsSplittableFrame::GetPrevInFlow() const
 154 {
 155   return (GetStateBits() & NS_FRAME_IS_FLUID_CONTINUATION) ? mPrevContinuation : nsnull;
 156 }
 157
 158 NS_METHOD nsSplittableFrame::SetPrevInFlow(nsIFrame* aFrame)
 159 {
 160   NS_ASSERTION (!aFrame || GetType() == aFrame->GetType(), "setting a prev in flow with incorrect type!");
 161   NS_ASSERTION (!IsInPrevContinuationChain(aFrame, this), "creating a loop in continuation chain!");
 162   mPrevContinuation = aFrame;
 163   AddStateBits(NS_FRAME_IS_FLUID_CONTINUATION);
 164   return NS_OK;
 165 }
 166
 167 nsIFrame* nsSplittableFrame::GetNextInFlow() const
 168 {
 169   return mNextContinuation && (mNextContinuation->GetStateBits() & NS_FRAME_IS_FLUID_CONTINUATION) ?
 170     mNextContinuation : nsnull;
 171 }
 172
 173 NS_METHOD nsSplittableFrame::SetNextInFlow(nsIFrame* aFrame)
 174 {
 175   NS_ASSERTION (!aFrame || GetType() == aFrame->GetType(),  "setting a next in flow with incorrect type!");
 176   NS_ASSERTION (!IsInNextContinuationChain(aFrame, this), "creating a loop in continuation chain!");
 177   mNextContinuation = aFrame;
 178   if (aFrame)
 179     aFrame->AddStateBits(NS_FRAME_IS_FLUID_CONTINUATION);
 180   return NS_OK;
 181 }
 182
 183 nsIFrame* nsSplittableFrame::GetFirstInFlow() const
 184 {
 185   nsSplittableFrame* firstInFlow = const_cast<nsSplittableFrame*>(this);
 186   while (nsIFrame *prev = firstInFlow->GetPrevInFlow())  {
 187     firstInFlow = static_cast<nsSplittableFrame*>(prev);
 188   }
 189   NS_POSTCONDITION(firstInFlow, "illegal state in flow chain.");
 190   return firstInFlow;
 191 }
 192
 193 nsIFrame* nsSplittableFrame::GetLastInFlow() const
 194 {
 195   nsSplittableFrame* lastInFlow = const_cast<nsSplittableFrame*>(this);
 196   while (nsIFrame* next = lastInFlow->GetNextInFlow())  {
 197     lastInFlow = static_cast<nsSplittableFrame*>(next);
 198   }
 199   NS_POSTCONDITION(lastInFlow, "illegal state in flow chain.");
 200   return lastInFlow;
 201 }
 202
 203 // Remove this frame from the flow. Connects prev in flow and next in flow
 204 void
 205 nsSplittableFrame::RemoveFromFlow(nsIFrame* aFrame)
 206 {
 207   nsIFrame* prevContinuation = aFrame->GetPrevContinuation();
 208   nsIFrame* nextContinuation = aFrame->GetNextContinuation();
 209
 210   // The new continuation is fluid only if the continuation on both sides
 211   // of the removed frame was fluid
 212   if (aFrame->GetPrevInFlow() && aFrame->GetNextInFlow()) {
 213     if (prevContinuation) {
 214       prevContinuation->SetNextInFlow(nextContinuation);
 215     }
 216     if (nextContinuation) {
 217       nextContinuation->SetPrevInFlow(prevContinuation);
 218     }
 219   } else {
 220     if (prevContinuation) {
 221       prevContinuation->SetNextContinuation(nextContinuation);
 222     }
 223     if (nextContinuation) {
 224       nextContinuation->SetPrevContinuation(prevContinuation);
 225     }
 226   }
 227
 228   aFrame->SetPrevInFlow(nsnull);
 229   aFrame->SetNextInFlow(nsnull);
 230 }
 231
 232 // Detach from previous frame in flow
 233 void
 234 nsSplittableFrame::BreakFromPrevFlow(nsIFrame* aFrame)
 235 {
 236   nsIFrame* prevInFlow = aFrame->GetPrevInFlow();
 237   // If this frame has a non-fluid continuation, transfer it to its prevInFlow
 238   nsIFrame* nextNonFluid = nsnull;
 239   nsIFrame* nextContinuation = aFrame->GetNextContinuation();
 240   if (nextContinuation && !(nextContinuation->GetStateBits() & NS_FRAME_IS_FLUID_CONTINUATION)) {
 241     nextNonFluid = nextContinuation;
 242     aFrame->SetNextContinuation(nsnull);
 243   }
 244   if (prevInFlow) {
 245     if (nextNonFluid) {
 246       prevInFlow->SetNextContinuation(nextNonFluid);
 247       nextNonFluid->SetPrevContinuation(prevInFlow);
 248     } else {
 249       prevInFlow->SetNextInFlow(nsnull);
 250     }
 251     aFrame->SetPrevInFlow(nsnull);
 252   }
 253 }
 254
 255 #ifdef DEBUG
 256 void
 257 nsSplittableFrame::DumpBaseRegressionData(nsPresContext* aPresContext, FILE* out, PRInt32 aIndent, PRBool aIncludeStyleData)
 258 {
 259   nsFrame::DumpBaseRegressionData(aPresContext, out, aIndent, aIncludeStyleData);
 260   if (nsnull != mNextContinuation) {
 261     IndentBy(out, aIndent);
 262     fprintf(out, "<next-continuation va=\"%ld\"/>\n", PRUptrdiff(mNextContinuation));
 263   }
 264   if (nsnull != mPrevContinuation) {
 265     IndentBy(out, aIndent);
 266     fprintf(out, "<prev-continuation va=\"%ld\"/>\n", PRUptrdiff(mPrevContinuation));
 267   }
 268
 269 }
 270 #endif