The Tor Browser: layout/generic/nsBlockReflowState.cpp@b8a032363ba2 (annotated)

layout/generic/nsBlockReflowState.cpp@b8a032363ba2 (annotated)

layout/generic/nsBlockReflowState.cpp

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 // vim:cindent:ts=2:et:sw=2:
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 /* state used in reflow of block frames */
 #include "nsBlockReflowState.h"
 #include "mozilla/DebugOnly.h"
 #include "nsBlockFrame.h"
 #include "nsLineLayout.h"
 #include "nsPresContext.h"
 #include "nsIFrameInlines.h"
 #include "mozilla/AutoRestore.h"
 #include <algorithm>
 #ifdef DEBUG
 #include "nsBlockDebugFlags.h"
 #endif
 using namespace mozilla;
 using namespace mozilla::layout;
 nsBlockReflowState::nsBlockReflowState(const nsHTMLReflowState& aReflowState,
                                        nsPresContext* aPresContext,
                                        nsBlockFrame* aFrame,
                                        bool aTopMarginRoot,
                                        bool aBottomMarginRoot,
                                        bool aBlockNeedsFloatManager,
                                        nscoord aConsumedHeight)
   : mBlock(aFrame),
     mPresContext(aPresContext),
     mReflowState(aReflowState),
     mPushedFloats(nullptr),
     mOverflowTracker(nullptr),
     mPrevBottomMargin(),
     mLineNumber(0),
     mFlags(0),
     mFloatBreakType(NS_STYLE_CLEAR_NONE),
     mConsumedHeight(aConsumedHeight)
 {
   SetFlag(BRS_ISFIRSTINFLOW, aFrame->GetPrevInFlow() == nullptr);
   SetFlag(BRS_ISOVERFLOWCONTAINER,
           IS_TRUE_OVERFLOW_CONTAINER(aFrame));
   const nsMargin& borderPadding = BorderPadding();
   mContainerWidth = aReflowState.ComputedWidth() +
                     aReflowState.ComputedPhysicalBorderPadding().LeftRight();
   if (aTopMarginRoot || 0 != aReflowState.ComputedPhysicalBorderPadding().top) {
     SetFlag(BRS_ISTOPMARGINROOT, true);
   }
   if (aBottomMarginRoot || 0 != aReflowState.ComputedPhysicalBorderPadding().bottom) {
     SetFlag(BRS_ISBOTTOMMARGINROOT, true);
   }
   if (GetFlag(BRS_ISTOPMARGINROOT)) {
     SetFlag(BRS_APPLYTOPMARGIN, true);
   }
   if (aBlockNeedsFloatManager) {
     SetFlag(BRS_FLOAT_MGR, true);
   }
   mFloatManager = aReflowState.mFloatManager;
   NS_ASSERTION(mFloatManager,
                "FloatManager should be set in nsBlockReflowState" );
   if (mFloatManager) {
     // Save the coordinate system origin for later.
     mFloatManager->GetTranslation(mFloatManagerX, mFloatManagerY);
     mFloatManager->PushState(&mFloatManagerStateBefore); // never popped
   }
   mReflowStatus = NS_FRAME_COMPLETE;
   mNextInFlow = static_cast<nsBlockFrame*>(mBlock->GetNextInFlow());
   NS_WARN_IF_FALSE(NS_UNCONSTRAINEDSIZE != aReflowState.ComputedWidth(),
                    "have unconstrained width; this should only result from "
                    "very large sizes, not attempts at intrinsic width "
                    "calculation");
   mContentArea.width = aReflowState.ComputedWidth();
   // Compute content area height. Unlike the width, if we have a
   // specified style height we ignore it since extra content is
   // managed by the "overflow" property. When we don't have a
   // specified style height then we may end up limiting our height if
   // the availableHeight is constrained (this situation occurs when we
   // are paginated).
   if (NS_UNCONSTRAINEDSIZE != aReflowState.AvailableHeight()) {
     // We are in a paginated situation. The bottom edge is just inside
     // the bottom border and padding. The content area height doesn't
     // include either border or padding edge.
     mBottomEdge = aReflowState.AvailableHeight() - borderPadding.bottom;
     mContentArea.height = std::max(0, mBottomEdge - borderPadding.top);
   }
   else {
     // When we are not in a paginated situation then we always use
     // an constrained height.
     SetFlag(BRS_UNCONSTRAINEDHEIGHT, true);
     mContentArea.height = mBottomEdge = NS_UNCONSTRAINEDSIZE;
   }
   mContentArea.x = borderPadding.left;
   mY = mContentArea.y = borderPadding.top;
   mPrevChild = nullptr;
   mCurrentLine = aFrame->end_lines();
   mMinLineHeight = aReflowState.CalcLineHeight();
 }
 nscoord
 nsBlockReflowState::GetConsumedHeight()
 {
   if (mConsumedHeight == NS_INTRINSICSIZE) {
     mConsumedHeight = mBlock->GetConsumedHeight();
   }
   return mConsumedHeight;
 }
 void
 nsBlockReflowState::ComputeReplacedBlockOffsetsForFloats(nsIFrame* aFrame,
                                                          const nsRect& aFloatAvailableSpace,
                                                          nscoord& aLeftResult,
                                                          nscoord& aRightResult)
 {
   // The frame is clueless about the float manager and therefore we
   // only give it free space. An example is a table frame - the
   // tables do not flow around floats.
   // However, we can let its margins intersect floats.
   NS_ASSERTION(aFloatAvailableSpace.x >= mContentArea.x, "bad avail space rect x");
   NS_ASSERTION(aFloatAvailableSpace.width == 0 ||
                aFloatAvailableSpace.XMost() <= mContentArea.XMost(),
                "bad avail space rect width");
   nscoord leftOffset, rightOffset;
   if (aFloatAvailableSpace.width == mContentArea.width) {
     // We don't need to compute margins when there are no floats around.
     leftOffset = 0;
     rightOffset = 0;
   } else {
     nsMargin frameMargin;
     nsCSSOffsetState os(aFrame, mReflowState.rendContext, mContentArea.width);
     frameMargin = os.ComputedPhysicalMargin();
     nscoord leftFloatXOffset = aFloatAvailableSpace.x - mContentArea.x;
     leftOffset = std::max(leftFloatXOffset, frameMargin.left) -
                  frameMargin.left;
     leftOffset = std::max(leftOffset, 0); // in case of negative margin
     nscoord rightFloatXOffset =
       mContentArea.XMost() - aFloatAvailableSpace.XMost();
     rightOffset = std::max(rightFloatXOffset, frameMargin.right) -
                   frameMargin.right;
     rightOffset = std::max(rightOffset, 0); // in case of negative margin
   }
   aLeftResult = leftOffset;
   aRightResult = rightOffset;
 }
 // Compute the amount of available space for reflowing a block frame
 // at the current Y coordinate. This method assumes that
 // GetAvailableSpace has already been called.
 void
 nsBlockReflowState::ComputeBlockAvailSpace(nsIFrame* aFrame,
                                            const nsStyleDisplay* aDisplay,
                                            const nsFlowAreaRect& aFloatAvailableSpace,
                                            bool aBlockAvoidsFloats,
                                            nsRect& aResult)
 {
 #ifdef REALLY_NOISY_REFLOW
   printf("CBAS frame=%p has floats %d\n",
          aFrame, aFloatAvailableSpace.mHasFloats);
 #endif
   aResult.y = mY;
   aResult.height = GetFlag(BRS_UNCONSTRAINEDHEIGHT)
     ? NS_UNCONSTRAINEDSIZE
     : mReflowState.AvailableHeight() - mY;
   // mY might be greater than mBottomEdge if the block's top margin pushes
   // it off the page/column. Negative available height can confuse other code
   // and is nonsense in principle.
   // XXX Do we really want this condition to be this restrictive (i.e.,
   // more restrictive than it used to be)?  The |else| here is allowed
   // by the CSS spec, but only out of desperation given implementations,
   // and the behavior it leads to is quite undesirable (it can cause
   // things to become extremely narrow when they'd fit quite well a
   // little bit lower).  Should the else be a quirk or something that
   // applies to a specific set of frame classes and no new ones?
   // If we did that, then for those frames where the condition below is
   // true but nsBlockFrame::BlockCanIntersectFloats is false,
   // nsBlockFrame::WidthToClearPastFloats would need to use the
   // shrink-wrap formula, max(MIN_WIDTH, min(avail width, PREF_WIDTH))
   // rather than just using MIN_WIDTH.
   NS_ASSERTION(nsBlockFrame::BlockCanIntersectFloats(aFrame) ==
                  !aBlockAvoidsFloats,
                "unexpected replaced width");
   if (!aBlockAvoidsFloats) {
     if (aFloatAvailableSpace.mHasFloats) {
       // Use the float-edge property to determine how the child block
       // will interact with the float.
       const nsStyleBorder* borderStyle = aFrame->StyleBorder();
       switch (borderStyle->mFloatEdge) {
         default:
         case NS_STYLE_FLOAT_EDGE_CONTENT:  // content and only content does runaround of floats
           // The child block will flow around the float. Therefore
           // give it all of the available space.
           aResult.x = mContentArea.x;
           aResult.width = mContentArea.width;
           break;
         case NS_STYLE_FLOAT_EDGE_MARGIN:
           {
             // The child block's margins should be placed adjacent to,
             // but not overlap the float.
             aResult.x = aFloatAvailableSpace.mRect.x;
             aResult.width = aFloatAvailableSpace.mRect.width;
           }
           break;
       }
     }
     else {
       // Since there are no floats present the float-edge property
       // doesn't matter therefore give the block element all of the
       // available space since it will flow around the float itself.
       aResult.x = mContentArea.x;
       aResult.width = mContentArea.width;
     }
   }
   else {
     nscoord leftOffset, rightOffset;
     ComputeReplacedBlockOffsetsForFloats(aFrame, aFloatAvailableSpace.mRect,
                                          leftOffset, rightOffset);
     aResult.x = mContentArea.x + leftOffset;
     aResult.width = mContentArea.width - leftOffset - rightOffset;
   }
 #ifdef REALLY_NOISY_REFLOW
   printf("  CBAS: result %d %d %d %d\n", aResult.x, aResult.y, aResult.width, aResult.height);
 #endif
 }
 nsFlowAreaRect
 nsBlockReflowState::GetFloatAvailableSpaceWithState(
                       nscoord aY,
                       nsFloatManager::SavedState *aState) const
 {
 #ifdef DEBUG
   // Verify that the caller setup the coordinate system properly
   nscoord wx, wy;
   mFloatManager->GetTranslation(wx, wy);
   NS_ASSERTION((wx == mFloatManagerX) && (wy == mFloatManagerY),
                "bad coord system");
 #endif
   nscoord height = (mContentArea.height == nscoord_MAX)
                      ? nscoord_MAX : std::max(mContentArea.YMost() - aY, 0);
   nsFlowAreaRect result =
     mFloatManager->GetFlowArea(aY, nsFloatManager::BAND_FROM_POINT,
                                height, mContentArea, aState);
   // Keep the width >= 0 for compatibility with nsSpaceManager.
   if (result.mRect.width < 0)
     result.mRect.width = 0;
 #ifdef DEBUG
   if (nsBlockFrame::gNoisyReflow) {
     nsFrame::IndentBy(stdout, nsBlockFrame::gNoiseIndent);
     printf("GetAvailableSpace: band=%d,%d,%d,%d hasfloats=%d\n",
            result.mRect.x, result.mRect.y, result.mRect.width,
            result.mRect.height, result.mHasFloats);
   }
 #endif
   return result;
 }
 nsFlowAreaRect
 nsBlockReflowState::GetFloatAvailableSpaceForHeight(
                       nscoord aY, nscoord aHeight,
                       nsFloatManager::SavedState *aState) const
 {
 #ifdef DEBUG
   // Verify that the caller setup the coordinate system properly
   nscoord wx, wy;
   mFloatManager->GetTranslation(wx, wy);
   NS_ASSERTION((wx == mFloatManagerX) && (wy == mFloatManagerY),
                "bad coord system");
 #endif
   nsFlowAreaRect result =
     mFloatManager->GetFlowArea(aY, nsFloatManager::WIDTH_WITHIN_HEIGHT,
                                aHeight, mContentArea, aState);
   // Keep the width >= 0 for compatibility with nsSpaceManager.
   if (result.mRect.width < 0)
     result.mRect.width = 0;
 #ifdef DEBUG
   if (nsBlockFrame::gNoisyReflow) {
     nsFrame::IndentBy(stdout, nsBlockFrame::gNoiseIndent);
     printf("GetAvailableSpaceForHeight: space=%d,%d,%d,%d hasfloats=%d\n",
            result.mRect.x, result.mRect.y, result.mRect.width,
            result.mRect.height, result.mHasFloats);
   }
 #endif
   return result;
 }
 /*
  * Reconstruct the vertical margin before the line |aLine| in order to
  * do an incremental reflow that begins with |aLine| without reflowing
  * the line before it.  |aLine| may point to the fencepost at the end of
  * the line list, and it is used this way since we (for now, anyway)
  * always need to recover margins at the end of a block.
  *
  * The reconstruction involves walking backward through the line list to
  * find any collapsed margins preceding the line that would have been in
  * the reflow state's |mPrevBottomMargin| when we reflowed that line in
  * a full reflow (under the rule in CSS2 that all adjacent vertical
  * margins of blocks collapse).
  */
 void
 nsBlockReflowState::ReconstructMarginAbove(nsLineList::iterator aLine)
 {
   mPrevBottomMargin.Zero();
   nsBlockFrame *block = mBlock;
   nsLineList::iterator firstLine = block->begin_lines();
   for (;;) {
     --aLine;
     if (aLine->IsBlock()) {
       mPrevBottomMargin = aLine->GetCarriedOutBottomMargin();
       break;
     }
     if (!aLine->IsEmpty()) {
       break;
     }
     if (aLine == firstLine) {
       // If the top margin was carried out (and thus already applied),
       // set it to zero.  Either way, we're done.
       if (!GetFlag(BRS_ISTOPMARGINROOT)) {
         mPrevBottomMargin.Zero();
       }
       break;
     }
   }
 }
 void
 nsBlockReflowState::SetupPushedFloatList()
 {
   NS_ABORT_IF_FALSE(!GetFlag(BRS_PROPTABLE_FLOATCLIST) == !mPushedFloats,
                     "flag mismatch");
   if (!GetFlag(BRS_PROPTABLE_FLOATCLIST)) {
     // If we're being re-Reflow'd without our next-in-flow having been
     // reflowed, some pushed floats from our previous reflow might
     // still be on our pushed floats list.  However, that's
     // actually fine, since they'll all end up being stolen and
     // reordered into the correct order again.
     // (nsBlockFrame::ReflowDirtyLines ensures that any lines with
     // pushed floats are reflowed.)
     mPushedFloats = mBlock->EnsurePushedFloats();
     SetFlag(BRS_PROPTABLE_FLOATCLIST, true);
   }
 }
 void
 nsBlockReflowState::AppendPushedFloat(nsIFrame* aFloatCont)
 {
   SetupPushedFloatList();
   aFloatCont->AddStateBits(NS_FRAME_IS_PUSHED_FLOAT);
   mPushedFloats->AppendFrame(mBlock, aFloatCont);
 }
 /**
  * Restore information about floats into the float manager for an
  * incremental reflow, and simultaneously push the floats by
  * |aDeltaY|, which is the amount |aLine| was pushed relative to its
  * parent.  The recovery of state is one of the things that makes
  * incremental reflow O(N^2) and this state should really be kept
  * around, attached to the frame tree.
  */
 void
 nsBlockReflowState::RecoverFloats(nsLineList::iterator aLine,
                                   nscoord aDeltaY)
 {
   if (aLine->HasFloats()) {
     // Place the floats into the space-manager again. Also slide
     // them, just like the regular frames on the line.
     nsFloatCache* fc = aLine->GetFirstFloat();
     while (fc) {
       nsIFrame* floatFrame = fc->mFloat;
       if (aDeltaY != 0) {
         floatFrame->MovePositionBy(nsPoint(0, aDeltaY));
         nsContainerFrame::PositionFrameView(floatFrame);
         nsContainerFrame::PositionChildViews(floatFrame);
       }
 #ifdef DEBUG
       if (nsBlockFrame::gNoisyReflow || nsBlockFrame::gNoisyFloatManager) {
         nscoord tx, ty;
         mFloatManager->GetTranslation(tx, ty);
         nsFrame::IndentBy(stdout, nsBlockFrame::gNoiseIndent);
         printf("RecoverFloats: txy=%d,%d (%d,%d) ",
                tx, ty, mFloatManagerX, mFloatManagerY);
         nsFrame::ListTag(stdout, floatFrame);
         nsRect region = nsFloatManager::GetRegionFor(floatFrame);
         printf(" aDeltaY=%d region={%d,%d,%d,%d}\n",
                aDeltaY, region.x, region.y, region.width, region.height);
       }
 #endif
       mFloatManager->AddFloat(floatFrame,
                               nsFloatManager::GetRegionFor(floatFrame));
       fc = fc->Next();
     }
   } else if (aLine->IsBlock()) {
     nsBlockFrame::RecoverFloatsFor(aLine->mFirstChild, *mFloatManager);
   }
 }
 /**
  * Everything done in this function is done O(N) times for each pass of
  * reflow so it is O(N*M) where M is the number of incremental reflow
  * passes.  That's bad.  Don't do stuff here.
  *
  * When this function is called, |aLine| has just been slid by |aDeltaY|
  * and the purpose of RecoverStateFrom is to ensure that the
  * nsBlockReflowState is in the same state that it would have been in
  * had the line just been reflowed.
  *
  * Most of the state recovery that we have to do involves floats.
  */
 void
 nsBlockReflowState::RecoverStateFrom(nsLineList::iterator aLine,
                                      nscoord aDeltaY)
 {
   // Make the line being recovered the current line
   mCurrentLine = aLine;
   // Place floats for this line into the float manager
   if (aLine->HasFloats() || aLine->IsBlock()) {
     RecoverFloats(aLine, aDeltaY);
 #ifdef DEBUG
     if (nsBlockFrame::gNoisyReflow || nsBlockFrame::gNoisyFloatManager) {
       mFloatManager->List(stdout);
     }
 #endif
   }
 }
 // This is called by the line layout's AddFloat method when a
 // place-holder frame is reflowed in a line. If the float is a
 // left-most child (it's x coordinate is at the line's left margin)
 // then the float is place immediately, otherwise the float
 // placement is deferred until the line has been reflowed.
 // XXXldb This behavior doesn't quite fit with CSS1 and CSS2 --
 // technically we're supposed let the current line flow around the
 // float as well unless it won't fit next to what we already have.
 // But nobody else implements it that way...
 bool
 nsBlockReflowState::AddFloat(nsLineLayout*       aLineLayout,
                              nsIFrame*           aFloat,
                              nscoord             aAvailableWidth)
 {
   NS_PRECONDITION(aLineLayout, "must have line layout");
   NS_PRECONDITION(mBlock->end_lines() != mCurrentLine, "null ptr");
   NS_PRECONDITION(aFloat->GetStateBits() & NS_FRAME_OUT_OF_FLOW,
                   "aFloat must be an out-of-flow frame");
   NS_ABORT_IF_FALSE(aFloat->GetParent(), "float must have parent");
   NS_ABORT_IF_FALSE(aFloat->GetParent()->IsFrameOfType(nsIFrame::eBlockFrame),
                     "float's parent must be block");
   NS_ABORT_IF_FALSE(aFloat->GetParent() == mBlock ||
                     (aFloat->GetStateBits() & NS_FRAME_IS_PUSHED_FLOAT),
                     "float should be in this block unless it was marked as "
                     "pushed float");
   if (aFloat->GetStateBits() & NS_FRAME_IS_PUSHED_FLOAT) {
     // If, in a previous reflow, the float was pushed entirely to
     // another column/page, we need to steal it back.  (We might just
     // push it again, though.)  Likewise, if that previous reflow
     // reflowed this block but not its next continuation, we might need
     // to steal it from our own float-continuations list.
     //
     // For more about pushed floats, see the comment above
     // nsBlockFrame::DrainPushedFloats.
     nsBlockFrame *floatParent =
       static_cast<nsBlockFrame*>(aFloat->GetParent());
     floatParent->StealFrame(aFloat);
     aFloat->RemoveStateBits(NS_FRAME_IS_PUSHED_FLOAT);
     // Appending is fine, since if a float was pushed to the next
     // page/column, all later floats were also pushed.
     mBlock->mFloats.AppendFrame(mBlock, aFloat);
   }
   // Because we are in the middle of reflowing a placeholder frame
   // within a line (and possibly nested in an inline frame or two
   // that's a child of our block) we need to restore the space
   // manager's translation to the space that the block resides in
   // before placing the float.
   nscoord ox, oy;
   mFloatManager->GetTranslation(ox, oy);
   nscoord dx = ox - mFloatManagerX;
   nscoord dy = oy - mFloatManagerY;
   mFloatManager->Translate(-dx, -dy);
   bool placed;
   // Now place the float immediately if possible. Otherwise stash it
   // away in mPendingFloats and place it later.
   // If one or more floats has already been pushed to the next line,
   // don't let this one go on the current line, since that would violate
   // float ordering.
   nsRect floatAvailableSpace = GetFloatAvailableSpace().mRect;
   if (mBelowCurrentLineFloats.IsEmpty() &&
       (aLineLayout->LineIsEmpty() ||
        mBlock->ComputeFloatWidth(*this, floatAvailableSpace, aFloat)
        <= aAvailableWidth)) {
     // And then place it
     placed = FlowAndPlaceFloat(aFloat);
     if (placed) {
       // Pass on updated available space to the current inline reflow engine
       nsFlowAreaRect floatAvailSpace = GetFloatAvailableSpace(mY);
       nsRect availSpace(nsPoint(floatAvailSpace.mRect.x, mY),
                         floatAvailSpace.mRect.Size());
       aLineLayout->UpdateBand(availSpace, aFloat);
       // Record this float in the current-line list
       mCurrentLineFloats.Append(mFloatCacheFreeList.Alloc(aFloat));
     } else {
       (*aLineLayout->GetLine())->SetHadFloatPushed();
     }
   }
   else {
     // Always claim to be placed; we don't know whether we fit yet, so we
     // deal with this in PlaceBelowCurrentLineFloats
     placed = true;
     // This float will be placed after the line is done (it is a
     // below-current-line float).
     mBelowCurrentLineFloats.Append(mFloatCacheFreeList.Alloc(aFloat));
   }
   // Restore coordinate system
   mFloatManager->Translate(dx, dy);
   return placed;
 }
 bool
 nsBlockReflowState::CanPlaceFloat(nscoord aFloatWidth,
                                   const nsFlowAreaRect& aFloatAvailableSpace)
 {
   // A float fits at a given vertical position if there are no floats at
   // its horizontal position (no matter what its width) or if its width
   // fits in the space remaining after prior floats have been placed.
   // FIXME: We should allow overflow by up to half a pixel here (bug 21193).
   return !aFloatAvailableSpace.mHasFloats ||
          aFloatAvailableSpace.mRect.width >= aFloatWidth;
 }
 static nscoord
 FloatMarginWidth(const nsHTMLReflowState& aCBReflowState,
                  nscoord aFloatAvailableWidth,
                  nsIFrame *aFloat,
                  const nsCSSOffsetState& aFloatOffsetState)
 {
   AutoMaybeDisableFontInflation an(aFloat);
   return aFloat->ComputeSize(
     aCBReflowState.rendContext,
     nsSize(aCBReflowState.ComputedWidth(),
            aCBReflowState.ComputedHeight()),
     aFloatAvailableWidth,
     nsSize(aFloatOffsetState.ComputedPhysicalMargin().LeftRight(),
            aFloatOffsetState.ComputedPhysicalMargin().TopBottom()),
     nsSize(aFloatOffsetState.ComputedPhysicalBorderPadding().LeftRight() -
              aFloatOffsetState.ComputedPhysicalPadding().LeftRight(),
            aFloatOffsetState.ComputedPhysicalBorderPadding().TopBottom() -
              aFloatOffsetState.ComputedPhysicalPadding().TopBottom()),
     nsSize(aFloatOffsetState.ComputedPhysicalPadding().LeftRight(),
            aFloatOffsetState.ComputedPhysicalPadding().TopBottom()),
     true).width +
   aFloatOffsetState.ComputedPhysicalMargin().LeftRight() +
   aFloatOffsetState.ComputedPhysicalBorderPadding().LeftRight();
 }
 bool
 nsBlockReflowState::FlowAndPlaceFloat(nsIFrame* aFloat)
 {
   // Save away the Y coordinate before placing the float. We will
   // restore mY at the end after placing the float. This is
   // necessary because any adjustments to mY during the float
   // placement are for the float only, not for any non-floating
   // content.
   AutoRestore<nscoord> restoreY(mY);
   // FIXME: Should give AutoRestore a getter for the value to avoid this.
   const nscoord saveY = mY;
   // Grab the float's display information
   const nsStyleDisplay* floatDisplay = aFloat->StyleDisplay();
   // The float's old region, so we can propagate damage.
   nsRect oldRegion = nsFloatManager::GetRegionFor(aFloat);
   // Enforce CSS2 9.5.1 rule [2], i.e., make sure that a float isn't
   // ``above'' another float that preceded it in the flow.
   mY = std::max(mFloatManager->GetLowestFloatTop(), mY);
   // See if the float should clear any preceding floats...
   // XXX We need to mark this float somehow so that it gets reflowed
   // when floats are inserted before it.
   if (NS_STYLE_CLEAR_NONE != floatDisplay->mBreakType) {
     // XXXldb Does this handle vertical margins correctly?
     mY = ClearFloats(mY, floatDisplay->mBreakType);
   }
     // Get the band of available space
   nsFlowAreaRect floatAvailableSpace = GetFloatAvailableSpace(mY);
   nsRect adjustedAvailableSpace = mBlock->AdjustFloatAvailableSpace(*this,
                                     floatAvailableSpace.mRect, aFloat);
   NS_ASSERTION(aFloat->GetParent() == mBlock,
                "Float frame has wrong parent");
   nsCSSOffsetState offsets(aFloat, mReflowState.rendContext,
                            mReflowState.ComputedWidth());
   nscoord floatMarginWidth = FloatMarginWidth(mReflowState,
                                               adjustedAvailableSpace.width,
                                               aFloat, offsets);
   nsMargin floatMargin; // computed margin
   nsMargin floatOffsets;
   nsReflowStatus reflowStatus;
   // If it's a floating first-letter, we need to reflow it before we
   // know how wide it is (since we don't compute which letters are part
   // of the first letter until reflow!).
   bool isLetter = aFloat->GetType() == nsGkAtoms::letterFrame;
   if (isLetter) {
     mBlock->ReflowFloat(*this, adjustedAvailableSpace, aFloat, floatMargin,
                         floatOffsets, false, reflowStatus);
     floatMarginWidth = aFloat->GetSize().width + floatMargin.LeftRight();
     NS_ASSERTION(NS_FRAME_IS_COMPLETE(reflowStatus),
                  "letter frames shouldn't break, and if they do now, "
                  "then they're breaking at the wrong point");
   }
   // Find a place to place the float. The CSS2 spec doesn't want
   // floats overlapping each other or sticking out of the containing
   // block if possible (CSS2 spec section 9.5.1, see the rule list).
   NS_ASSERTION((NS_STYLE_FLOAT_LEFT == floatDisplay->mFloats) ||
 	       (NS_STYLE_FLOAT_RIGHT == floatDisplay->mFloats),
 	       "invalid float type");
   // Can the float fit here?
   bool keepFloatOnSameLine = false;
   // Are we required to place at least part of the float because we're
   // at the top of the page (to avoid an infinite loop of pushing and
   // breaking).
   bool mustPlaceFloat =
     mReflowState.mFlags.mIsTopOfPage && IsAdjacentWithTop();
   for (;;) {
     if (mReflowState.AvailableHeight() != NS_UNCONSTRAINEDSIZE &&
         floatAvailableSpace.mRect.height <= 0 &&
         !mustPlaceFloat) {
       // No space, nowhere to put anything.
       PushFloatPastBreak(aFloat);
       return false;
     }
     if (CanPlaceFloat(floatMarginWidth, floatAvailableSpace)) {
       // We found an appropriate place.
       break;
     }
     // Nope. try to advance to the next band.
     if (NS_STYLE_DISPLAY_TABLE != floatDisplay->mDisplay ||
           eCompatibility_NavQuirks != mPresContext->CompatibilityMode() ) {
       mY += floatAvailableSpace.mRect.height;
       if (adjustedAvailableSpace.height != NS_UNCONSTRAINEDSIZE) {
         adjustedAvailableSpace.height -= floatAvailableSpace.mRect.height;
       }
       floatAvailableSpace = GetFloatAvailableSpace(mY);
     } else {
       // This quirk matches the one in nsBlockFrame::AdjustFloatAvailableSpace
       // IE handles float tables in a very special way
       // see if the previous float is also a table and has "align"
       nsFloatCache* fc = mCurrentLineFloats.Head();
       nsIFrame* prevFrame = nullptr;
       while (fc) {
         if (fc->mFloat == aFloat) {
           break;
         }
         prevFrame = fc->mFloat;
         fc = fc->Next();
       }
       if(prevFrame) {
         //get the frame type
         if (nsGkAtoms::tableOuterFrame == prevFrame->GetType()) {
           //see if it has "align="
           // IE makes a difference between align and he float property
           nsIContent* content = prevFrame->GetContent();
           if (content) {
             // we're interested only if previous frame is align=left
             // IE messes things up when "right" (overlapping frames)
             if (content->AttrValueIs(kNameSpaceID_None, nsGkAtoms::align,
                                      NS_LITERAL_STRING("left"), eIgnoreCase)) {
               keepFloatOnSameLine = true;
               // don't advance to next line (IE quirkie behaviour)
               // it breaks rule CSS2/9.5.1/1, but what the hell
               // since we cannot evangelize the world
               break;
             }
           }
         }
       }
       // the table does not fit anymore in this line so advance to next band
       mY += floatAvailableSpace.mRect.height;
       // To match nsBlockFrame::AdjustFloatAvailableSpace, we have to
       // get a new width for the new band.
       floatAvailableSpace = GetFloatAvailableSpace(mY);
       adjustedAvailableSpace = mBlock->AdjustFloatAvailableSpace(*this,
                                  floatAvailableSpace.mRect, aFloat);
       floatMarginWidth = FloatMarginWidth(mReflowState,
                                           adjustedAvailableSpace.width,
                                           aFloat, offsets);
     }
     mustPlaceFloat = false;
   }
   // If the float is continued, it will get the same absolute x value as its prev-in-flow
   // We don't worry about the geometry of the prev in flow, let the continuation
   // place and size itself as required.
   // Assign an x and y coordinate to the float.
   nscoord floatX, floatY;
   if (NS_STYLE_FLOAT_LEFT == floatDisplay->mFloats) {
     floatX = floatAvailableSpace.mRect.x;
   }
   else {
     if (!keepFloatOnSameLine) {
       floatX = floatAvailableSpace.mRect.XMost() - floatMarginWidth;
     }
     else {
       // this is the IE quirk (see few lines above)
       // the table is kept in the same line: don't let it overlap the
       // previous float
       floatX = floatAvailableSpace.mRect.x;
     }
   }
   // CSS2 spec, 9.5.1 rule [4]: "A floating box's outer top may not
   // be higher than the top of its containing block."  (Since the
   // containing block is the content edge of the block box, this
   // means the margin edge of the float can't be higher than the
   // content edge of the block that contains it.)
   floatY = std::max(mY, mContentArea.y);
   // Reflow the float after computing its vertical position so it knows
   // where to break.
   if (!isLetter) {
     bool pushedDown = mY != saveY;
     mBlock->ReflowFloat(*this, adjustedAvailableSpace, aFloat, floatMargin,
                         floatOffsets, pushedDown, reflowStatus);
   }
   if (aFloat->GetPrevInFlow())
     floatMargin.top = 0;
   if (NS_FRAME_IS_NOT_COMPLETE(reflowStatus))
     floatMargin.bottom = 0;
   // In the case that we're in columns and not splitting floats, we need
   // to check here that the float's height fit, and if it didn't, bail.
   // (This code is only for DISABLE_FLOAT_BREAKING_IN_COLUMNS .)
   //
   // Likewise, if none of the float fit, and it needs to be pushed in
   // its entirety to the next page (NS_FRAME_IS_TRUNCATED or
   // NS_INLINE_IS_BREAK_BEFORE), we need to do the same.
   if ((mContentArea.height != NS_UNCONSTRAINEDSIZE &&
        adjustedAvailableSpace.height == NS_UNCONSTRAINEDSIZE &&
        !mustPlaceFloat &&
        aFloat->GetSize().height + floatMargin.TopBottom() >
          mContentArea.YMost() - floatY) ||
       NS_FRAME_IS_TRUNCATED(reflowStatus) ||
       NS_INLINE_IS_BREAK_BEFORE(reflowStatus)) {
     PushFloatPastBreak(aFloat);
     return false;
   }
   // We can't use aFloat->ShouldAvoidBreakInside(mReflowState) here since
   // its mIsTopOfPage may be true even though the float isn't at the
   // top when floatY > 0.
   if (mContentArea.height != NS_UNCONSTRAINEDSIZE &&
       !mustPlaceFloat && (!mReflowState.mFlags.mIsTopOfPage || floatY > 0) &&
       NS_STYLE_PAGE_BREAK_AVOID == aFloat->StyleDisplay()->mBreakInside &&
       (!NS_FRAME_IS_FULLY_COMPLETE(reflowStatus) ||
        aFloat->GetSize().height + floatMargin.TopBottom() >
          mContentArea.YMost() - floatY) &&
       !aFloat->GetPrevInFlow()) {
     PushFloatPastBreak(aFloat);
     return false;
   }
   // Calculate the actual origin of the float frame's border rect
   // relative to the parent block; the margin must be added in
   // to get the border rect
   nsPoint origin(floatMargin.left + floatX,
                  floatMargin.top + floatY);
   // If float is relatively positioned, factor that in as well
   nsHTMLReflowState::ApplyRelativePositioning(aFloat, floatOffsets, &origin);
   // Position the float and make sure and views are properly
   // positioned. We need to explicitly position its child views as
   // well, since we're moving the float after flowing it.
   bool moved = aFloat->GetPosition() != origin;
   if (moved) {
     aFloat->SetPosition(origin);
     nsContainerFrame::PositionFrameView(aFloat);
     nsContainerFrame::PositionChildViews(aFloat);
   }
   // Update the float combined area state
   // XXX Floats should really just get invalidated here if necessary
   mFloatOverflowAreas.UnionWith(aFloat->GetOverflowAreas() + origin);
   // Place the float in the float manager
   // calculate region
   nsRect region = nsFloatManager::CalculateRegionFor(aFloat, floatMargin);
   // if the float split, then take up all of the vertical height
   if (NS_FRAME_IS_NOT_COMPLETE(reflowStatus) &&
       (NS_UNCONSTRAINEDSIZE != mContentArea.height)) {
     region.height = std::max(region.height, mContentArea.height - floatY);
   }
   DebugOnly<nsresult> rv =
     mFloatManager->AddFloat(aFloat, region);
   NS_ABORT_IF_FALSE(NS_SUCCEEDED(rv), "bad float placement");
   // store region
   nsFloatManager::StoreRegionFor(aFloat, region);
   // If the float's dimensions have changed, note the damage in the
   // float manager.
   if (!region.IsEqualEdges(oldRegion)) {
     // XXXwaterson conservative: we could probably get away with noting
     // less damage; e.g., if only height has changed, then only note the
     // area into which the float has grown or from which the float has
     // shrunk.
     nscoord top = std::min(region.y, oldRegion.y);
     nscoord bottom = std::max(region.YMost(), oldRegion.YMost());
     mFloatManager->IncludeInDamage(top, bottom);
   }
   if (!NS_FRAME_IS_FULLY_COMPLETE(reflowStatus)) {
     mBlock->SplitFloat(*this, aFloat, reflowStatus);
   }
 #ifdef NOISY_FLOATMANAGER
   nscoord tx, ty;
   mFloatManager->GetTranslation(tx, ty);
   nsFrame::ListTag(stdout, mBlock);
   printf(": FlowAndPlaceFloat: AddFloat: txy=%d,%d (%d,%d) {%d,%d,%d,%d}\n",
          tx, ty, mFloatManagerX, mFloatManagerY,
          region.x, region.y, region.width, region.height);
 #endif
 #ifdef DEBUG
   if (nsBlockFrame::gNoisyReflow) {
     nsRect r = aFloat->GetRect();
     nsFrame::IndentBy(stdout, nsBlockFrame::gNoiseIndent);
     printf("placed float: ");
     nsFrame::ListTag(stdout, aFloat);
     printf(" %d,%d,%d,%d\n", r.x, r.y, r.width, r.height);
   }
 #endif
   return true;
 }
 void
 nsBlockReflowState::PushFloatPastBreak(nsIFrame *aFloat)
 {
   // This ensures that we:
   //  * don't try to place later but smaller floats (which CSS says
   //    must have their tops below the top of this float)
   //  * don't waste much time trying to reflow this float again until
   //    after the break
   if (aFloat->StyleDisplay()->mFloats == NS_STYLE_FLOAT_LEFT) {
     mFloatManager->SetPushedLeftFloatPastBreak();
   } else {
     NS_ABORT_IF_FALSE(aFloat->StyleDisplay()->mFloats ==
                         NS_STYLE_FLOAT_RIGHT,
                       "unexpected float value");
     mFloatManager->SetPushedRightFloatPastBreak();
   }
   // Put the float on the pushed floats list, even though it
   // isn't actually a continuation.
   DebugOnly<nsresult> rv = mBlock->StealFrame(aFloat);
   NS_ASSERTION(NS_SUCCEEDED(rv), "StealFrame should succeed");
   AppendPushedFloat(aFloat);
   NS_FRAME_SET_OVERFLOW_INCOMPLETE(mReflowStatus);
 }
 /**
  * Place below-current-line floats.
  */
 void
 nsBlockReflowState::PlaceBelowCurrentLineFloats(nsFloatCacheFreeList& aList,
                                                 nsLineBox* aLine)
 {
   nsFloatCache* fc = aList.Head();
   while (fc) {
 #ifdef DEBUG
     if (nsBlockFrame::gNoisyReflow) {
       nsFrame::IndentBy(stdout, nsBlockFrame::gNoiseIndent);
       printf("placing bcl float: ");
       nsFrame::ListTag(stdout, fc->mFloat);
       printf("\n");
     }
 #endif
     // Place the float
     bool placed = FlowAndPlaceFloat(fc->mFloat);
     nsFloatCache *next = fc->Next();
     if (!placed) {
       aList.Remove(fc);
       delete fc;
       aLine->SetHadFloatPushed();
     }
     fc = next;
   }
 }
 nscoord
 nsBlockReflowState::ClearFloats(nscoord aY, uint8_t aBreakType,
                                 nsIFrame *aReplacedBlock,
                                 uint32_t aFlags)
 {
 #ifdef DEBUG
   if (nsBlockFrame::gNoisyReflow) {
     nsFrame::IndentBy(stdout, nsBlockFrame::gNoiseIndent);
     printf("clear floats: in: aY=%d\n", aY);
   }
 #endif
 #ifdef NOISY_FLOAT_CLEARING
   printf("nsBlockReflowState::ClearFloats: aY=%d breakType=%d\n",
          aY, aBreakType);
   mFloatManager->List(stdout);
 #endif
   if (!mFloatManager->HasAnyFloats()) {
     return aY;
   }
   nscoord newY = aY;
   if (aBreakType != NS_STYLE_CLEAR_NONE) {
     newY = mFloatManager->ClearFloats(newY, aBreakType, aFlags);
   }
   if (aReplacedBlock) {
     for (;;) {
       nsFlowAreaRect floatAvailableSpace = GetFloatAvailableSpace(newY);
       if (!floatAvailableSpace.mHasFloats) {
         // If there aren't any floats here, then we always fit.
         // We check this before calling WidthToClearPastFloats, which is
         // somewhat expensive.
         break;
       }
       nsBlockFrame::ReplacedElementWidthToClear replacedWidth =
         nsBlockFrame::WidthToClearPastFloats(*this, floatAvailableSpace.mRect,
                                              aReplacedBlock);
       if (std::max(floatAvailableSpace.mRect.x - mContentArea.x,
                  replacedWidth.marginLeft) +
             replacedWidth.borderBoxWidth +
             std::max(mContentArea.XMost() - floatAvailableSpace.mRect.XMost(),
                    replacedWidth.marginRight) <=
           mContentArea.width) {
         break;
       }
       // See the analogous code for inlines in nsBlockFrame::DoReflowInlineFrames
       if (floatAvailableSpace.mRect.height > 0) {
         // See if there's room in the next band.
         newY += floatAvailableSpace.mRect.height;
       } else {
         if (mReflowState.AvailableHeight() != NS_UNCONSTRAINEDSIZE) {
           // Stop trying to clear here; we'll just get pushed to the
           // next column or page and try again there.
           break;
         }
         NS_NOTREACHED("avail space rect with zero height!");
         newY += 1;
       }
     }
   }
 #ifdef DEBUG
   if (nsBlockFrame::gNoisyReflow) {
     nsFrame::IndentBy(stdout, nsBlockFrame::gNoiseIndent);
     printf("clear floats: out: y=%d\n", newY);
   }
 #endif
   return newY;
 }

The Tor Browser / annotate

layout/generic/nsBlockReflowState.cpp@b8a032363ba2 (annotated)

layout/generic/nsBlockReflowState.cpp