layout/generic/nsPageContentFrame.cpp

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  37 #include "nsPageContentFrame.h"
  38 #include "nsPageFrame.h"
  39 #include "nsPlaceholderFrame.h"
  40 #include "nsCSSFrameConstructor.h"
  41 #include "nsHTMLContainerFrame.h"
  42 #include "nsHTMLParts.h"
  43 #include "nsIContent.h"
  44 #include "nsPresContext.h"
  45 #include "nsIRenderingContext.h"
  46 #include "nsGkAtoms.h"
  47 #include "nsIPresShell.h"
  48 #include "nsIDeviceContext.h"
  49 #include "nsReadableUtils.h"
  50 #include "nsSimplePageSequence.h"
  51 #include "nsDisplayList.h"
  52
  53 nsIFrame*
  54 NS_NewPageContentFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
  55 {
  56   return new (aPresShell) nsPageContentFrame(aContext);
  57 }
  58
  59 /* virtual */ nsSize
  60 nsPageContentFrame::ComputeSize(nsIRenderingContext *aRenderingContext,
  61                                 nsSize aCBSize, nscoord aAvailableWidth,
  62                                 nsSize aMargin, nsSize aBorder, nsSize aPadding,
  63                                 PRBool aShrinkWrap)
  64 {
  65   NS_ASSERTION(mPD, "Pages are supposed to have page data");
  66   nscoord height = (!mPD || mPD->mReflowSize.height == NS_UNCONSTRAINEDSIZE)
  67                    ? NS_UNCONSTRAINEDSIZE
  68                    : (mPD->mReflowSize.height - mPD->mReflowMargin.TopBottom());
  69   return nsSize(aAvailableWidth, height);
  70 }
  71
  72 /**
  73  * Returns true if aFrame is a placeholder for one of our fixed frames.
  74  */
  75 inline PRBool
  76 nsPageContentFrame::IsFixedPlaceholder(nsIFrame* aFrame)
  77 {
  78   if (!aFrame || nsGkAtoms::placeholderFrame != aFrame->GetType())
  79     return PR_FALSE;
  80
  81   return static_cast<nsPlaceholderFrame*>(aFrame)->GetOutOfFlowFrame()
  82            ->GetParent() == this;
  83 }
  84
  85 /**
  86  * Steals replicated fixed placeholder frames from aDocRoot so they don't
  87  * get in the way of reflow.
  88  */
  89 inline nsFrameList
  90 nsPageContentFrame::StealFixedPlaceholders(nsIFrame* aDocRoot)
  91 {
  92   nsPresContext* presContext = PresContext();
  93   nsFrameList list;
  94   if (GetPrevInFlow()) {
  95     for (nsIFrame* f = aDocRoot->GetFirstChild(nsnull);
  96         IsFixedPlaceholder(f); f = aDocRoot->GetFirstChild(nsnull)) {
  97       nsresult rv = static_cast<nsContainerFrame*>(aDocRoot)
  98                       ->StealFrame(presContext, f);
  99       NS_ENSURE_SUCCESS(rv, list);
 100       list.AppendFrame(nsnull, f);
 101     }
 102   }
 103   return list;
 104 }
 105
 106 /**
 107  * Restores stolen replicated fixed placeholder frames to aDocRoot.
 108  */
 109 static inline nsresult
 110 ReplaceFixedPlaceholders(nsIFrame*    aDocRoot,
 111                          nsFrameList& aPlaceholderList)
 112 {
 113   nsresult rv = NS_OK;
 114   if (aPlaceholderList.NotEmpty()) {
 115     rv = static_cast<nsContainerFrame*>(aDocRoot)
 116            ->AddFrames(aPlaceholderList.FirstChild(), nsnull);
 117   }
 118   return rv;
 119 }
 120
 121 NS_IMETHODIMP
 122 nsPageContentFrame::Reflow(nsPresContext*           aPresContext,
 123                            nsHTMLReflowMetrics&     aDesiredSize,
 124                            const nsHTMLReflowState& aReflowState,
 125                            nsReflowStatus&          aStatus)
 126 {
 127   DO_GLOBAL_REFLOW_COUNT("nsPageContentFrame");
 128   DISPLAY_REFLOW(aPresContext, this, aReflowState, aDesiredSize, aStatus);
 129   aStatus = NS_FRAME_COMPLETE;  // initialize out parameter
 130   nsresult rv = NS_OK;
 131
 132   // A PageContentFrame must always have one child: the doc root element's frame.
 133   // We only need to get overflow frames if we don't already have that child;
 134   // Also we need to avoid repeating the call to ReplicateFixedFrames.
 135   nsPageContentFrame* prevPageContentFrame = static_cast<nsPageContentFrame*>
 136                                                (GetPrevInFlow());
 137   if (mFrames.IsEmpty() && prevPageContentFrame) {
 138     // Pull the doc root frame's continuation and copy fixed frames.
 139     nsIFrame* overflow = prevPageContentFrame->GetOverflowFrames(aPresContext, PR_TRUE);
 140     NS_ASSERTION(overflow && !overflow->GetNextSibling(),
 141                  "must have doc root as pageContentFrame's only child");
 142     nsHTMLContainerFrame::ReparentFrameView(aPresContext, overflow, prevPageContentFrame, this);
 143     // Prepend overflow to the page content frame. There may already be
 144     // children placeholders which don't get reflowed but must not be
 145     // lost until the page content frame is destroyed.
 146     mFrames.InsertFrames(this, nsnull, overflow);
 147     nsresult rv = aPresContext->PresShell()->FrameConstructor()
 148                     ->ReplicateFixedFrames(this);
 149     NS_ENSURE_SUCCESS(rv, rv);
 150   }
 151
 152   // Resize our frame allowing it only to be as big as we are
 153   // XXX Pay attention to the page's border and padding...
 154   if (mFrames.NotEmpty()) {
 155     nsIFrame* frame = mFrames.FirstChild();
 156     nsSize  maxSize(aReflowState.availableWidth, aReflowState.availableHeight);
 157     nsHTMLReflowState kidReflowState(aPresContext, aReflowState, frame, maxSize);
 158
 159     mPD->mPageContentSize  = aReflowState.availableWidth;
 160
 161     // Get replicated fixed frames' placeholders out of the way
 162     nsFrameList stolenPlaceholders = StealFixedPlaceholders(frame);
 163
 164     // Reflow the page content area
 165     rv = ReflowChild(frame, aPresContext, aDesiredSize, kidReflowState, 0, 0, 0, aStatus);
 166     NS_ENSURE_SUCCESS(rv, rv);
 167
 168     // Put removed fixed placeholders back
 169     rv = ReplaceFixedPlaceholders(frame, stolenPlaceholders);
 170     NS_ENSURE_SUCCESS(rv, rv);
 171
 172     if (!NS_FRAME_IS_FULLY_COMPLETE(aStatus)) {
 173       nsIFrame* nextFrame = frame->GetNextInFlow();
 174       NS_ASSERTION(nextFrame || aStatus & NS_FRAME_REFLOW_NEXTINFLOW,
 175         "If it's incomplete and has no nif yet, it must flag a nif reflow.");
 176       if (!nextFrame) {
 177         nsresult rv = nsHTMLContainerFrame::CreateNextInFlow(aPresContext,
 178                                               this, frame, nextFrame);
 179         NS_ENSURE_SUCCESS(rv, rv);
 180         frame->SetNextSibling(nextFrame->GetNextSibling());
 181         nextFrame->SetNextSibling(nsnull);
 182         SetOverflowFrames(aPresContext, nextFrame);
 183         // Root overflow containers will be normal children of
 184         // the pageContentFrame, but that's ok because there
 185         // aren't any other frames we need to isolate them from
 186         // during reflow.
 187       }
 188       if (NS_FRAME_OVERFLOW_IS_INCOMPLETE(aStatus)) {
 189         nextFrame->AddStateBits(NS_FRAME_IS_OVERFLOW_CONTAINER);
 190       }
 191     }
 192
 193     // The document element's background should cover the entire canvas, so
 194     // take into account the combined area and any space taken up by
 195     // absolutely positioned elements
 196     nsMargin padding(0,0,0,0);
 197
 198     // XXXbz this screws up percentage padding (sets padding to zero
 199     // in the percentage padding case)
 200     kidReflowState.mStylePadding->GetPadding(padding);
 201
 202     // First check the combined area
 203     if (NS_FRAME_OUTSIDE_CHILDREN & frame->GetStateBits()) {
 204       // The background covers the content area and padding area, so check
 205       // for children sticking outside the child frame's padding edge
 206       if (aDesiredSize.mOverflowArea.XMost() > aDesiredSize.width) {
 207         mPD->mPageContentXMost =
 208           aDesiredSize.mOverflowArea.XMost() +
 209           kidReflowState.mStyleBorder->GetActualBorderWidth(NS_SIDE_RIGHT) +
 210           padding.right;
 211       }
 212     }
 213
 214     // Place and size the child
 215     FinishReflowChild(frame, aPresContext, &kidReflowState, aDesiredSize, 0, 0, 0);
 216
 217     NS_ASSERTION(aPresContext->IsDynamic() || !NS_FRAME_IS_FULLY_COMPLETE(aStatus) ||
 218                   !frame->GetNextInFlow(), "bad child flow list");
 219   }
 220   // Reflow our fixed frames
 221   nsReflowStatus fixedStatus = NS_FRAME_COMPLETE;
 222   mFixedContainer.Reflow(this, aPresContext, aReflowState, fixedStatus,
 223                          aReflowState.availableWidth,
 224                          aReflowState.availableHeight,
 225                          PR_FALSE, PR_TRUE, PR_TRUE); // XXX could be optimized
 226   NS_ASSERTION(NS_FRAME_IS_COMPLETE(fixedStatus), "fixed frames can be truncated, but not incomplete");
 227
 228   // Return our desired size
 229   aDesiredSize.width = aReflowState.availableWidth;
 230   if (aReflowState.availableHeight != NS_UNCONSTRAINEDSIZE) {
 231     aDesiredSize.height = aReflowState.availableHeight;
 232   }
 233
 234   NS_FRAME_SET_TRUNCATION(aStatus, aReflowState, aDesiredSize);
 235   return NS_OK;
 236 }
 237
 238 nsIAtom*
 239 nsPageContentFrame::GetType() const
 240 {
 241   return nsGkAtoms::pageContentFrame;
 242 }
 243
 244 #ifdef DEBUG
 245 NS_IMETHODIMP
 246 nsPageContentFrame::GetFrameName(nsAString& aResult) const
 247 {
 248   return MakeFrameName(NS_LITERAL_STRING("PageContent"), aResult);
 249 }
 250 #endif
 251
 252 /* virtual */ PRBool
 253 nsPageContentFrame::IsContainingBlock() const
 254 {
 255   return PR_TRUE;
 256 }