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 "gfxUtils.h"
  14 #include "mozilla/gfx/2D.h"
  15 #include "nsDisplayList.h"
  16 #include "nsFrameManager.h"
  17 #include "nsLayoutUtils.h"
  18 #include "nsPresContext.h"
  19 #include "nsRenderingContext.h"
  20 #include "nsIFrameInlines.h"
  21
  22 using namespace mozilla;
  23 using namespace mozilla::gfx;
  24
  25 nsIFrame*
  26 NS_NewPlaceholderFrame(nsIPresShell* aPresShell, nsStyleContext* aContext,
  27                        nsFrameState aTypeBit)
  28 {
  29   return new (aPresShell) nsPlaceholderFrame(aContext, aTypeBit);
  30 }
  31
  32 NS_IMPL_FRAMEARENA_HELPERS(nsPlaceholderFrame)
  33
  34 #ifdef DEBUG
  35 NS_QUERYFRAME_HEAD(nsPlaceholderFrame)
  36   NS_QUERYFRAME_ENTRY(nsPlaceholderFrame)
  37 NS_QUERYFRAME_TAIL_INHERITING(nsFrame)
  38 #endif
  39
  40 /* virtual */ nsSize
  41 nsPlaceholderFrame::GetMinSize(nsBoxLayoutState& aBoxLayoutState)
  42 {
  43   nsSize size(0, 0);
  44   DISPLAY_MIN_SIZE(this, size);
  45   return size;
  46 }
  47
  48 /* virtual */ nsSize
  49 nsPlaceholderFrame::GetPrefSize(nsBoxLayoutState& aBoxLayoutState)
  50 {
  51   nsSize size(0, 0);
  52   DISPLAY_PREF_SIZE(this, size);
  53   return size;
  54 }
  55
  56 /* virtual */ nsSize
  57 nsPlaceholderFrame::GetMaxSize(nsBoxLayoutState& aBoxLayoutState)
  58 {
  59   nsSize size(NS_INTRINSICSIZE, NS_INTRINSICSIZE);
  60   DISPLAY_MAX_SIZE(this, size);
  61   return size;
  62 }
  63
  64 /* virtual */ void
  65 nsPlaceholderFrame::AddInlineMinISize(nsRenderingContext* aRenderingContext,
  66                                       nsIFrame::InlineMinISizeData* aData)
  67 {
  68   // Override AddInlineMinWith so that *nothing* happens.  In
  69   // particular, we don't want to zero out |aData->trailingWhitespace|,
  70   // since nsLineLayout skips placeholders when trimming trailing
  71   // whitespace, and we don't want to set aData->skipWhitespace to
  72   // false.
  73
  74   // ...but push floats onto the list
  75   if (mOutOfFlowFrame->IsFloating()) {
  76     nscoord floatWidth =
  77       nsLayoutUtils::IntrinsicForContainer(aRenderingContext,
  78                                            mOutOfFlowFrame,
  79                                            nsLayoutUtils::MIN_ISIZE);
  80     aData->floats.AppendElement(
  81       InlineIntrinsicISizeData::FloatInfo(mOutOfFlowFrame, floatWidth));
  82   }
  83 }
  84
  85 /* virtual */ void
  86 nsPlaceholderFrame::AddInlinePrefISize(nsRenderingContext* aRenderingContext,
  87                                        nsIFrame::InlinePrefISizeData* aData)
  88 {
  89   // Override AddInlinePrefWith so that *nothing* happens.  In
  90   // particular, we don't want to zero out |aData->trailingWhitespace|,
  91   // since nsLineLayout skips placeholders when trimming trailing
  92   // whitespace, and we don't want to set aData->skipWhitespace to
  93   // false.
  94
  95   // ...but push floats onto the list
  96   if (mOutOfFlowFrame->IsFloating()) {
  97     nscoord floatWidth =
  98       nsLayoutUtils::IntrinsicForContainer(aRenderingContext,
  99                                            mOutOfFlowFrame,
 100                                            nsLayoutUtils::PREF_ISIZE);
 101     aData->floats.AppendElement(
 102       InlineIntrinsicISizeData::FloatInfo(mOutOfFlowFrame, floatWidth));
 103   }
 104 }
 105
 106 void
 107 nsPlaceholderFrame::Reflow(nsPresContext*           aPresContext,
 108                            nsHTMLReflowMetrics&     aDesiredSize,
 109                            const nsHTMLReflowState& aReflowState,
 110                            nsReflowStatus&          aStatus)
 111 {
 112 #ifdef DEBUG
 113   // We should be getting reflowed before our out-of-flow.
 114   // If this is our first reflow, and our out-of-flow has already received its
 115   // first reflow (before us), complain.
 116   // XXXdholbert This "look for a previous continuation or IB-split sibling"
 117   // code could use nsLayoutUtils::GetPrevContinuationOrIBSplitSibling(), if
 118   // we ever add a function like that. (We currently have a "Next" version.)
 119   if ((GetStateBits() & NS_FRAME_FIRST_REFLOW) &&
 120       !(mOutOfFlowFrame->GetStateBits() & NS_FRAME_FIRST_REFLOW)) {
 121
 122     // Unfortunately, this can currently happen when the placeholder is in a
 123     // later continuation or later IB-split sibling than its out-of-flow (as
 124     // is the case in some of our existing unit tests). So for now, in that
 125     // case, we'll warn instead of asserting.
 126     bool isInContinuationOrIBSplit = false;
 127     nsIFrame* ancestor = this;
 128     while ((ancestor = ancestor->GetParent())) {
 129       if (ancestor->GetPrevContinuation() ||
 130           ancestor->Properties().Get(IBSplitPrevSibling())) {
 131         isInContinuationOrIBSplit = true;
 132         break;
 133       }
 134     }
 135
 136     if (isInContinuationOrIBSplit) {
 137       NS_WARNING("Out-of-flow frame got reflowed before its placeholder");
 138     } else {
 139       NS_ERROR("Out-of-flow frame got reflowed before its placeholder");
 140     }
 141   }
 142 #endif
 143
 144   DO_GLOBAL_REFLOW_COUNT("nsPlaceholderFrame");
 145   DISPLAY_REFLOW(aPresContext, this, aReflowState, aDesiredSize, aStatus);
 146   aDesiredSize.ClearSize();
 147
 148   aStatus = NS_FRAME_COMPLETE;
 149   NS_FRAME_SET_TRUNCATION(aStatus, aReflowState, aDesiredSize);
 150 }
 151
 152 void
 153 nsPlaceholderFrame::DestroyFrom(nsIFrame* aDestructRoot)
 154 {
 155   nsIFrame* oof = mOutOfFlowFrame;
 156   if (oof) {
 157     // Unregister out-of-flow frame
 158     nsFrameManager* fm = PresContext()->GetPresShell()->FrameManager();
 159     fm->UnregisterPlaceholderFrame(this);
 160     mOutOfFlowFrame = nullptr;
 161     // If aDestructRoot is not an ancestor of the out-of-flow frame,
 162     // then call RemoveFrame on it here.
 163     // Also destroy it here if it's a popup frame. (Bug 96291)
 164     if ((GetStateBits() & PLACEHOLDER_FOR_POPUP) ||
 165         !nsLayoutUtils::IsProperAncestorFrame(aDestructRoot, oof)) {
 166       ChildListID listId = nsLayoutUtils::GetChildListNameFor(oof);
 167       fm->RemoveFrame(listId, oof);
 168     }
 169     // else oof will be destroyed by its parent
 170   }
 171
 172   nsFrame::DestroyFrom(aDestructRoot);
 173 }
 174
 175 nsIAtom*
 176 nsPlaceholderFrame::GetType() const
 177 {
 178   return nsGkAtoms::placeholderFrame;
 179 }
 180
 181 /* virtual */ bool
 182 nsPlaceholderFrame::CanContinueTextRun() const
 183 {
 184   if (!mOutOfFlowFrame) {
 185     return false;
 186   }
 187   // first-letter frames can continue text runs, and placeholders for floated
 188   // first-letter frames can too
 189   return mOutOfFlowFrame->CanContinueTextRun();
 190 }
 191
 192 nsStyleContext*
 193 nsPlaceholderFrame::GetParentStyleContext(nsIFrame** aProviderFrame) const
 194 {
 195   NS_PRECONDITION(GetParent(), "How can we not have a parent here?");
 196
 197   nsIContent* parentContent = mContent ? mContent->GetFlattenedTreeParent() : nullptr;
 198   if (parentContent) {
 199     nsStyleContext* sc =
 200       PresContext()->FrameManager()->GetDisplayContentsStyleFor(parentContent);
 201     if (sc) {
 202       *aProviderFrame = nullptr;
 203       return sc;
 204     }
 205   }
 206
 207   // Lie about our pseudo so we can step out of all anon boxes and
 208   // pseudo-elements.  The other option would be to reimplement the
 209   // {ib} split gunk here.
 210   *aProviderFrame = CorrectStyleParentFrame(GetParent(), nsGkAtoms::placeholderFrame);
 211   return *aProviderFrame ? (*aProviderFrame)->StyleContext() : nullptr;
 212 }
 213
 214
 215 #ifdef DEBUG
 216 static void
 217 PaintDebugPlaceholder(nsIFrame* aFrame, nsRenderingContext* aCtx,
 218                       const nsRect& aDirtyRect, nsPoint aPt)
 219 {
 220   ColorPattern cyan(ToDeviceColor(Color(0.f, 1.f, 1.f, 1.f)));
 221   DrawTarget* drawTarget = aCtx->GetDrawTarget();
 222   int32_t appUnitsPerDevPixel = aFrame->PresContext()->AppUnitsPerDevPixel();
 223
 224   nscoord x = nsPresContext::CSSPixelsToAppUnits(-5);
 225   nsRect r(aPt.x + x, aPt.y,
 226            nsPresContext::CSSPixelsToAppUnits(13),
 227            nsPresContext::CSSPixelsToAppUnits(3));
 228   drawTarget->FillRect(NSRectToRect(r, appUnitsPerDevPixel), cyan);
 229
 230   nscoord y = nsPresContext::CSSPixelsToAppUnits(-10);
 231   r = nsRect(aPt.x, aPt.y + y,
 232              nsPresContext::CSSPixelsToAppUnits(3),
 233              nsPresContext::CSSPixelsToAppUnits(10));
 234   drawTarget->FillRect(NSRectToRect(r, appUnitsPerDevPixel), cyan);
 235 }
 236 #endif // DEBUG
 237
 238 #if defined(DEBUG) || (defined(MOZ_REFLOW_PERF_DSP) && defined(MOZ_REFLOW_PERF))
 239
 240 void
 241 nsPlaceholderFrame::BuildDisplayList(nsDisplayListBuilder*   aBuilder,
 242                                      const nsRect&           aDirtyRect,
 243                                      const nsDisplayListSet& aLists)
 244 {
 245   DO_GLOBAL_REFLOW_COUNT_DSP("nsPlaceholderFrame");
 246
 247 #ifdef DEBUG
 248   if (GetShowFrameBorders()) {
 249     aLists.Outlines()->AppendNewToTop(
 250       new (aBuilder) nsDisplayGeneric(aBuilder, this, PaintDebugPlaceholder,
 251                                       "DebugPlaceholder",
 252                                       nsDisplayItem::TYPE_DEBUG_PLACEHOLDER));
 253   }
 254 #endif
 255 }
 256 #endif // DEBUG || (MOZ_REFLOW_PERF_DSP && MOZ_REFLOW_PERF)
 257
 258 #ifdef DEBUG_FRAME_DUMP
 259 nsresult
 260 nsPlaceholderFrame::GetFrameName(nsAString& aResult) const
 261 {
 262   return MakeFrameName(NS_LITERAL_STRING("Placeholder"), aResult);
 263 }
 264
 265 void
 266 nsPlaceholderFrame::List(FILE* out, const char* aPrefix, uint32_t aFlags) const
 267 {
 268   nsCString str;
 269   ListGeneric(str, aPrefix, aFlags);
 270
 271   if (mOutOfFlowFrame) {
 272     str += " outOfFlowFrame=";
 273     nsFrame::ListTag(str, mOutOfFlowFrame);
 274   }
 275   fprintf_stderr(out, "%s\n", str.get());
 276 }
 277 #endif