layout/generic/nsPlaceholderFrame.cpp

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 /*
   7  * rendering object for the point that anchors out-of-flow rendering
   8  * objects such as floats and absolutely positioned elements
   9  */
  10
  11 #include "nsPlaceholderFrame.h"
  12
  13 #include "nsDisplayList.h"
  14 #include "nsFrameManager.h"
  15 #include "nsLayoutUtils.h"
  16 #include "nsPresContext.h"
  17 #include "nsRenderingContext.h"
  18 #include "nsIFrameInlines.h"
  19
  20 nsIFrame*
  21 NS_NewPlaceholderFrame(nsIPresShell* aPresShell, nsStyleContext* aContext,
  22                        nsFrameState aTypeBit)
  23 {
  24   return new (aPresShell) nsPlaceholderFrame(aContext, aTypeBit);
  25 }
  26
  27 NS_IMPL_FRAMEARENA_HELPERS(nsPlaceholderFrame)
  28
  29 #ifdef DEBUG
  30 NS_QUERYFRAME_HEAD(nsPlaceholderFrame)
  31   NS_QUERYFRAME_ENTRY(nsPlaceholderFrame)
  32 NS_QUERYFRAME_TAIL_INHERITING(nsFrame)
  33 #endif
  34
  35 /* virtual */ nsSize
  36 nsPlaceholderFrame::GetMinSize(nsBoxLayoutState& aBoxLayoutState)
  37 {
  38   nsSize size(0, 0);
  39   DISPLAY_MIN_SIZE(this, size);
  40   return size;
  41 }
  42
  43 /* virtual */ nsSize
  44 nsPlaceholderFrame::GetPrefSize(nsBoxLayoutState& aBoxLayoutState)
  45 {
  46   nsSize size(0, 0);
  47   DISPLAY_PREF_SIZE(this, size);
  48   return size;
  49 }
  50
  51 /* virtual */ nsSize
  52 nsPlaceholderFrame::GetMaxSize(nsBoxLayoutState& aBoxLayoutState)
  53 {
  54   nsSize size(NS_INTRINSICSIZE, NS_INTRINSICSIZE);
  55   DISPLAY_MAX_SIZE(this, size);
  56   return size;
  57 }
  58
  59 /* virtual */ void
  60 nsPlaceholderFrame::AddInlineMinISize(nsRenderingContext* aRenderingContext,
  61                                       nsIFrame::InlineMinISizeData* aData)
  62 {
  63   // Override AddInlineMinWith so that *nothing* happens.  In
  64   // particular, we don't want to zero out |aData->trailingWhitespace|,
  65   // since nsLineLayout skips placeholders when trimming trailing
  66   // whitespace, and we don't want to set aData->skipWhitespace to
  67   // false.
  68
  69   // ...but push floats onto the list
  70   if (mOutOfFlowFrame->IsFloating()) {
  71     nscoord floatWidth =
  72       nsLayoutUtils::IntrinsicForContainer(aRenderingContext,
  73                                            mOutOfFlowFrame,
  74                                            nsLayoutUtils::MIN_ISIZE);
  75     aData->floats.AppendElement(
  76       InlineIntrinsicISizeData::FloatInfo(mOutOfFlowFrame, floatWidth));
  77   }
  78 }
  79
  80 /* virtual */ void
  81 nsPlaceholderFrame::AddInlinePrefISize(nsRenderingContext* aRenderingContext,
  82                                        nsIFrame::InlinePrefISizeData* aData)
  83 {
  84   // Override AddInlinePrefWith so that *nothing* happens.  In
  85   // particular, we don't want to zero out |aData->trailingWhitespace|,
  86   // since nsLineLayout skips placeholders when trimming trailing
  87   // whitespace, and we don't want to set aData->skipWhitespace to
  88   // false.
  89
  90   // ...but push floats onto the list
  91   if (mOutOfFlowFrame->IsFloating()) {
  92     nscoord floatWidth =
  93       nsLayoutUtils::IntrinsicForContainer(aRenderingContext,
  94                                            mOutOfFlowFrame,
  95                                            nsLayoutUtils::PREF_ISIZE);
  96     aData->floats.AppendElement(
  97       InlineIntrinsicISizeData::FloatInfo(mOutOfFlowFrame, floatWidth));
  98   }
  99 }
 100
 101 void
 102 nsPlaceholderFrame::Reflow(nsPresContext*           aPresContext,
 103                            nsHTMLReflowMetrics&     aDesiredSize,
 104                            const nsHTMLReflowState& aReflowState,
 105                            nsReflowStatus&          aStatus)
 106 {
 107 #ifdef DEBUG
 108   // We should be getting reflowed before our out-of-flow.
 109   // If this is our first reflow, and our out-of-flow has already received its
 110   // first reflow (before us), complain.
 111   // XXXdholbert This "look for a previous continuation or IB-split sibling"
 112   // code could use nsLayoutUtils::GetPrevContinuationOrIBSplitSibling(), if
 113   // we ever add a function like that. (We currently have a "Next" version.)
 114   if ((GetStateBits() & NS_FRAME_FIRST_REFLOW) &&
 115       !(mOutOfFlowFrame->GetStateBits() & NS_FRAME_FIRST_REFLOW)) {
 116
 117     // Unfortunately, this can currently happen when the placeholder is in a
 118     // later continuation or later IB-split sibling than its out-of-flow (as
 119     // is the case in some of our existing unit tests). So for now, in that
 120     // case, we'll warn instead of asserting.
 121     bool isInContinuationOrIBSplit = false;
 122     nsIFrame* ancestor = this;
 123     while ((ancestor = ancestor->GetParent())) {
 124       if (ancestor->GetPrevContinuation() ||
 125           ancestor->Properties().Get(IBSplitPrevSibling())) {
 126         isInContinuationOrIBSplit = true;
 127         break;
 128       }
 129     }
 130
 131     if (isInContinuationOrIBSplit) {
 132       NS_WARNING("Out-of-flow frame got reflowed before its placeholder");
 133     } else {
 134       NS_ERROR("Out-of-flow frame got reflowed before its placeholder");
 135     }
 136   }
 137 #endif
 138
 139   DO_GLOBAL_REFLOW_COUNT("nsPlaceholderFrame");
 140   DISPLAY_REFLOW(aPresContext, this, aReflowState, aDesiredSize, aStatus);
 141   aDesiredSize.ClearSize();
 142
 143   aStatus = NS_FRAME_COMPLETE;
 144   NS_FRAME_SET_TRUNCATION(aStatus, aReflowState, aDesiredSize);
 145 }
 146
 147 void
 148 nsPlaceholderFrame::DestroyFrom(nsIFrame* aDestructRoot)
 149 {
 150   nsIFrame* oof = mOutOfFlowFrame;
 151   if (oof) {
 152     // Unregister out-of-flow frame
 153     nsFrameManager* fm = PresContext()->GetPresShell()->FrameManager();
 154     fm->UnregisterPlaceholderFrame(this);
 155     mOutOfFlowFrame = nullptr;
 156     // If aDestructRoot is not an ancestor of the out-of-flow frame,
 157     // then call RemoveFrame on it here.
 158     // Also destroy it here if it's a popup frame. (Bug 96291)
 159     if ((GetStateBits() & PLACEHOLDER_FOR_POPUP) ||
 160         !nsLayoutUtils::IsProperAncestorFrame(aDestructRoot, oof)) {
 161       ChildListID listId = nsLayoutUtils::GetChildListNameFor(oof);
 162       fm->RemoveFrame(listId, oof);
 163     }
 164     // else oof will be destroyed by its parent
 165   }
 166
 167   nsFrame::DestroyFrom(aDestructRoot);
 168 }
 169
 170 nsIAtom*
 171 nsPlaceholderFrame::GetType() const
 172 {
 173   return nsGkAtoms::placeholderFrame;
 174 }
 175
 176 /* virtual */ bool
 177 nsPlaceholderFrame::CanContinueTextRun() const
 178 {
 179   if (!mOutOfFlowFrame) {
 180     return false;
 181   }
 182   // first-letter frames can continue text runs, and placeholders for floated
 183   // first-letter frames can too
 184   return mOutOfFlowFrame->CanContinueTextRun();
 185 }
 186
 187 nsIFrame*
 188 nsPlaceholderFrame::GetParentStyleContextFrame() const
 189 {
 190   NS_PRECONDITION(GetParent(), "How can we not have a parent here?");
 191
 192   // Lie about our pseudo so we can step out of all anon boxes and
 193   // pseudo-elements.  The other option would be to reimplement the
 194   // {ib} split gunk here.
 195   return CorrectStyleParentFrame(GetParent(), nsGkAtoms::placeholderFrame);
 196 }
 197
 198
 199 #ifdef DEBUG
 200 static void
 201 PaintDebugPlaceholder(nsIFrame* aFrame, nsRenderingContext* aCtx,
 202                       const nsRect& aDirtyRect, nsPoint aPt)
 203 {
 204   aCtx->SetColor(NS_RGB(0, 255, 255));
 205   nscoord x = nsPresContext::CSSPixelsToAppUnits(-5);
 206   aCtx->FillRect(aPt.x + x, aPt.y,
 207                  nsPresContext::CSSPixelsToAppUnits(13),
 208                  nsPresContext::CSSPixelsToAppUnits(3));
 209   nscoord y = nsPresContext::CSSPixelsToAppUnits(-10);
 210   aCtx->FillRect(aPt.x, aPt.y + y,
 211                  nsPresContext::CSSPixelsToAppUnits(3),
 212                  nsPresContext::CSSPixelsToAppUnits(10));
 213 }
 214 #endif // DEBUG
 215
 216 #if defined(DEBUG) || (defined(MOZ_REFLOW_PERF_DSP) && defined(MOZ_REFLOW_PERF))
 217
 218 void
 219 nsPlaceholderFrame::BuildDisplayList(nsDisplayListBuilder*   aBuilder,
 220                                      const nsRect&           aDirtyRect,
 221                                      const nsDisplayListSet& aLists)
 222 {
 223   DO_GLOBAL_REFLOW_COUNT_DSP("nsPlaceholderFrame");
 224
 225 #ifdef DEBUG
 226   if (GetShowFrameBorders()) {
 227     aLists.Outlines()->AppendNewToTop(
 228       new (aBuilder) nsDisplayGeneric(aBuilder, this, PaintDebugPlaceholder,
 229                                       "DebugPlaceholder",
 230                                       nsDisplayItem::TYPE_DEBUG_PLACEHOLDER));
 231   }
 232 #endif
 233 }
 234 #endif // DEBUG || (MOZ_REFLOW_PERF_DSP && MOZ_REFLOW_PERF)
 235
 236 #ifdef DEBUG_FRAME_DUMP
 237 nsresult
 238 nsPlaceholderFrame::GetFrameName(nsAString& aResult) const
 239 {
 240   return MakeFrameName(NS_LITERAL_STRING("Placeholder"), aResult);
 241 }
 242
 243 void
 244 nsPlaceholderFrame::List(FILE* out, const char* aPrefix, uint32_t aFlags) const
 245 {
 246   nsCString str;
 247   ListGeneric(str, aPrefix, aFlags);
 248
 249   if (mOutOfFlowFrame) {
 250     str += " outOfFlowFrame=";
 251     nsFrame::ListTag(str, mOutOfFlowFrame);
 252   }
 253   fprintf_stderr(out, "%s\n", str.get());
 254 }
 255 #endif