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

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

layout/generic/nsBlockReflowContext.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/. */
 /* class that a parent frame uses to reflow a block frame */
 #include "nsBlockReflowContext.h"
 #include "nsBlockReflowState.h"
 #include "nsFloatManager.h"
 #include "nsContainerFrame.h"
 #include "nsBlockFrame.h"
 #include "nsLineBox.h"
 #include "nsLayoutUtils.h"
 #ifdef DEBUG
 #undef  NOISY_MAX_ELEMENT_SIZE
 #undef   REALLY_NOISY_MAX_ELEMENT_SIZE
 #undef  NOISY_VERTICAL_MARGINS
 #else
 #undef  NOISY_MAX_ELEMENT_SIZE
 #undef   REALLY_NOISY_MAX_ELEMENT_SIZE
 #undef  NOISY_VERTICAL_MARGINS
 #endif
 nsBlockReflowContext::nsBlockReflowContext(nsPresContext* aPresContext,
                                            const nsHTMLReflowState& aParentRS)
   : mPresContext(aPresContext),
     mOuterReflowState(aParentRS),
     mMetrics(aParentRS.GetWritingMode())
 {
 }
 static nsIFrame* DescendIntoBlockLevelFrame(nsIFrame* aFrame)
 {
   nsIAtom* type = aFrame->GetType();
   if (type == nsGkAtoms::columnSetFrame)
     return DescendIntoBlockLevelFrame(aFrame->GetFirstPrincipalChild());
   return aFrame;
 }
 bool
 nsBlockReflowContext::ComputeCollapsedTopMargin(const nsHTMLReflowState& aRS,
   nsCollapsingMargin* aMargin, nsIFrame* aClearanceFrame,
   bool* aMayNeedRetry, bool* aBlockIsEmpty)
 {
   // Include frame's top margin
   aMargin->Include(aRS.ComputedPhysicalMargin().top);
   // The inclusion of the bottom margin when empty is done by the caller
   // since it doesn't need to be done by the top-level (non-recursive)
   // caller.
 #ifdef NOISY_VERTICAL_MARGINS
   nsFrame::ListTag(stdout, aRS.frame);
   printf(": %d => %d\n", aRS.ComputedPhysicalMargin().top, aMargin->get());
 #endif
   bool dirtiedLine = false;
   bool setBlockIsEmpty = false;
   // Calculate the frame's generational top-margin from its child
   // blocks. Note that if the frame has a non-zero top-border or
   // top-padding then this step is skipped because it will be a margin
   // root.  It is also skipped if the frame is a margin root for other
   // reasons.
   nsIFrame* frame = DescendIntoBlockLevelFrame(aRS.frame);
   nsPresContext* prescontext = frame->PresContext();
   nsBlockFrame* block = nullptr;
   if (0 == aRS.ComputedPhysicalBorderPadding().top) {
     block = nsLayoutUtils::GetAsBlock(frame);
     if (block) {
       bool topMarginRoot, unused;
       block->IsMarginRoot(&topMarginRoot, &unused);
       if (topMarginRoot) {
         block = nullptr;
       }
     }
   }
   // iterate not just through the lines of 'block' but also its
   // overflow lines and the normal and overflow lines of its next in
   // flows. Note that this will traverse some frames more than once:
   // for example, if A contains B and A->nextinflow contains
   // B->nextinflow, we'll traverse B->nextinflow twice. But this is
   // OK because our traversal is idempotent.
   for ( ;block; block = static_cast<nsBlockFrame*>(block->GetNextInFlow())) {
     for (int overflowLines = 0; overflowLines <= 1; ++overflowLines) {
       nsBlockFrame::line_iterator line;
       nsBlockFrame::line_iterator line_end;
       bool anyLines = true;
       if (overflowLines) {
         nsBlockFrame::FrameLines* frames = block->GetOverflowLines();
         nsLineList* lines = frames ? &frames->mLines : nullptr;
         if (!lines) {
           anyLines = false;
         } else {
           line = lines->begin();
           line_end = lines->end();
         }
       } else {
         line = block->begin_lines();
         line_end = block->end_lines();
       }
       for (; anyLines && line != line_end; ++line) {
         if (!aClearanceFrame && line->HasClearance()) {
           // If we don't have a clearance frame, then we're computing
           // the collapsed margin in the first pass, assuming that all
           // lines have no clearance. So clear their clearance flags.
           line->ClearHasClearance();
           line->MarkDirty();
           dirtiedLine = true;
         }
         bool isEmpty;
         if (line->IsInline()) {
           isEmpty = line->IsEmpty();
         } else {
           nsIFrame* kid = line->mFirstChild;
           if (kid == aClearanceFrame) {
             line->SetHasClearance();
             line->MarkDirty();
             dirtiedLine = true;
             goto done;
           }
           // Here is where we recur. Now that we have determined that a
           // generational collapse is required we need to compute the
           // child blocks margin and so in so that we can look into
           // it. For its margins to be computed we need to have a reflow
           // state for it.
           // We may have to construct an extra reflow state here if
           // we drilled down through a block wrapper. At the moment
           // we can only drill down one level so we only have to support
           // one extra reflow state.
           const nsHTMLReflowState* outerReflowState = &aRS;
           if (frame != aRS.frame) {
             NS_ASSERTION(frame->GetParent() == aRS.frame,
                          "Can only drill through one level of block wrapper");
             nsSize availSpace(aRS.ComputedWidth(), aRS.ComputedHeight());
             outerReflowState = new nsHTMLReflowState(prescontext,
                                                      aRS, frame, availSpace);
           }
           {
             nsSize availSpace(outerReflowState->ComputedWidth(),
                               outerReflowState->ComputedHeight());
             nsHTMLReflowState innerReflowState(prescontext,
                                                *outerReflowState, kid,
                                                availSpace);
             // Record that we're being optimistic by assuming the kid
             // has no clearance
             if (kid->StyleDisplay()->mBreakType != NS_STYLE_CLEAR_NONE) {
               *aMayNeedRetry = true;
             }
             if (ComputeCollapsedTopMargin(innerReflowState, aMargin, aClearanceFrame, aMayNeedRetry, &isEmpty)) {
               line->MarkDirty();
               dirtiedLine = true;
             }
             if (isEmpty)
               aMargin->Include(innerReflowState.ComputedPhysicalMargin().bottom);
           }
           if (outerReflowState != &aRS) {
             delete const_cast<nsHTMLReflowState*>(outerReflowState);
           }
         }
         if (!isEmpty) {
           if (!setBlockIsEmpty && aBlockIsEmpty) {
             setBlockIsEmpty = true;
             *aBlockIsEmpty = false;
           }
           goto done;
         }
       }
       if (!setBlockIsEmpty && aBlockIsEmpty) {
         // The first time we reach here is when this is the first block
         // and we have processed all its normal lines.
         setBlockIsEmpty = true;
         // All lines are empty, or we wouldn't be here!
         *aBlockIsEmpty = aRS.frame->IsSelfEmpty();
       }
     }
   }
   done:
   if (!setBlockIsEmpty && aBlockIsEmpty) {
     *aBlockIsEmpty = aRS.frame->IsEmpty();
   }
 #ifdef NOISY_VERTICAL_MARGINS
   nsFrame::ListTag(stdout, aRS.frame);
   printf(": => %d\n", aMargin->get());
 #endif
   return dirtiedLine;
 }
 nsresult
 nsBlockReflowContext::ReflowBlock(const nsRect&       aSpace,
                                   bool                aApplyTopMargin,
                                   nsCollapsingMargin& aPrevMargin,
                                   nscoord             aClearance,
                                   bool                aIsAdjacentWithTop,
                                   nsLineBox*          aLine,
                                   nsHTMLReflowState&  aFrameRS,
                                   nsReflowStatus&     aFrameReflowStatus,
                                   nsBlockReflowState& aState)
 {
   nsresult rv = NS_OK;
   mFrame = aFrameRS.frame;
   mSpace = aSpace;
   if (!aIsAdjacentWithTop) {
     aFrameRS.mFlags.mIsTopOfPage = false;  // make sure this is cleared
   }
   if (aApplyTopMargin) {
     mTopMargin = aPrevMargin;
 #ifdef NOISY_VERTICAL_MARGINS
     nsFrame::ListTag(stdout, mOuterReflowState.frame);
     printf(": reflowing ");
     nsFrame::ListTag(stdout, mFrame);
     printf(" margin => %d, clearance => %d\n", mTopMargin.get(), aClearance);
 #endif
     // Adjust the available height if its constrained so that the
     // child frame doesn't think it can reflow into its margin area.
     if (NS_UNCONSTRAINEDSIZE != aFrameRS.AvailableHeight()) {
       aFrameRS.AvailableHeight() -= mTopMargin.get() + aClearance;
     }
   }
   nscoord tx = 0, ty = 0;
   // The values of x and y do not matter for floats, so don't bother calculating
   // them. Floats are guaranteed to have their own float manager, so tx and ty
   // don't matter.  mX and mY don't matter becacuse they are only used in
   // PlaceBlock, which is not used for floats.
   if (aLine) {
     // Compute x/y coordinate where reflow will begin. Use the rules
     // from 10.3.3 to determine what to apply. At this point in the
     // reflow auto left/right margins will have a zero value.
     mX = tx = mSpace.x + aFrameRS.ComputedPhysicalMargin().left;
     mY = ty = mSpace.y + mTopMargin.get() + aClearance;
     if ((mFrame->GetStateBits() & NS_BLOCK_FLOAT_MGR) == 0)
       aFrameRS.mBlockDelta =
         mOuterReflowState.mBlockDelta + ty - aLine->BStart();
   }
   // Let frame know that we are reflowing it
   mFrame->WillReflow(mPresContext);
 #ifdef DEBUG
   mMetrics.Width() = nscoord(0xdeadbeef);
   mMetrics.Height() = nscoord(0xdeadbeef);
 #endif
   mOuterReflowState.mFloatManager->Translate(tx, ty);
   rv = mFrame->Reflow(mPresContext, mMetrics, aFrameRS, aFrameReflowStatus);
   mOuterReflowState.mFloatManager->Translate(-tx, -ty);
 #ifdef DEBUG
   if (!NS_INLINE_IS_BREAK_BEFORE(aFrameReflowStatus)) {
     if (CRAZY_SIZE(mMetrics.Width()) || CRAZY_SIZE(mMetrics.Height())) {
       printf("nsBlockReflowContext: ");
       nsFrame::ListTag(stdout, mFrame);
       printf(" metrics=%d,%d!\n", mMetrics.Width(), mMetrics.Height());
     }
     if ((mMetrics.Width() == nscoord(0xdeadbeef)) ||
         (mMetrics.Height() == nscoord(0xdeadbeef))) {
       printf("nsBlockReflowContext: ");
       nsFrame::ListTag(stdout, mFrame);
       printf(" didn't set w/h %d,%d!\n", mMetrics.Width(), mMetrics.Height());
     }
   }
 #endif
   if (!mFrame->HasOverflowAreas()) {
     mMetrics.SetOverflowAreasToDesiredBounds();
   }
   if (!NS_INLINE_IS_BREAK_BEFORE(aFrameReflowStatus) ||
       (mFrame->GetStateBits() & NS_FRAME_OUT_OF_FLOW)) {
     // If frame is complete and has a next-in-flow, we need to delete
     // them now. Do not do this when a break-before is signaled because
     // the frame is going to get reflowed again (and may end up wanting
     // a next-in-flow where it ends up), unless it is an out of flow frame.
     if (NS_FRAME_IS_FULLY_COMPLETE(aFrameReflowStatus)) {
       nsIFrame* kidNextInFlow = mFrame->GetNextInFlow();
       if (nullptr != kidNextInFlow) {
         // Remove all of the childs next-in-flows. Make sure that we ask
         // the right parent to do the removal (it's possible that the
         // parent is not this because we are executing pullup code).
         // Floats will eventually be removed via nsBlockFrame::RemoveFloat
         // which detaches the placeholder from the float.
         nsOverflowContinuationTracker::AutoFinish fini(aState.mOverflowTracker, mFrame);
         static_cast<nsContainerFrame*>(kidNextInFlow->GetParent())
           ->DeleteNextInFlowChild(kidNextInFlow, true);
       }
     }
   }
   return rv;
 }
 /**
  * Attempt to place the block frame within the available space.  If
  * it fits, apply horizontal positioning (CSS 10.3.3), collapse
  * margins (CSS2 8.3.1). Also apply relative positioning.
  */
 bool
 nsBlockReflowContext::PlaceBlock(const nsHTMLReflowState&  aReflowState,
                                  bool                      aForceFit,
                                  nsLineBox*                aLine,
                                  nsCollapsingMargin&       aBottomMarginResult,
                                  nsOverflowAreas&          aOverflowAreas,
                                  nsReflowStatus            aReflowStatus,
                                  nscoord                   aContainerWidth)
 {
   // Compute collapsed bottom margin value.
   if (NS_FRAME_IS_COMPLETE(aReflowStatus)) {
     aBottomMarginResult = mMetrics.mCarriedOutBottomMargin;
     aBottomMarginResult.Include(aReflowState.ComputedPhysicalMargin().bottom);
   } else {
     // The used bottom-margin is set to zero above a break.
     aBottomMarginResult.Zero();
   }
   nsPoint position(mX, mY);
   nscoord backupContainingBlockAdvance = 0;
   // Check whether the block's bottom margin collapses with its top
   // margin. See CSS 2.1 section 8.3.1; those rules seem to match
   // nsBlockFrame::IsEmpty(). Any such block must have zero height so
   // check that first. Note that a block can have clearance and still
   // have adjoining top/bottom margins, because the clearance goes
   // above the top margin.
   // Mark the frame as non-dirty; it has been reflowed (or we wouldn't
   // be here), and we don't want to assert in CachedIsEmpty()
   mFrame->RemoveStateBits(NS_FRAME_IS_DIRTY);
   bool empty = 0 == mMetrics.Height() && aLine->CachedIsEmpty();
   if (empty) {
     // Collapse the bottom margin with the top margin that was already
     // applied.
     aBottomMarginResult.Include(mTopMargin);
 #ifdef NOISY_VERTICAL_MARGINS
     printf("  ");
     nsFrame::ListTag(stdout, mOuterReflowState.frame);
     printf(": ");
     nsFrame::ListTag(stdout, mFrame);
     printf(" -- collapsing top & bottom margin together; y=%d spaceY=%d\n",
            position.y, mSpace.y);
 #endif
     // Section 8.3.1 of CSS 2.1 says that blocks with adjoining
     // top/bottom margins whose top margin collapses with their
     // parent's top margin should have their top border-edge at the
     // top border-edge of their parent. We actually don't have to do
     // anything special to make this happen. In that situation,
     // nsBlockFrame::ShouldApplyTopMargin will have returned false,
     // and mTopMargin and aClearance will have been zero in
     // ReflowBlock.
     // If we did apply our top margin, but now we're collapsing it
     // into the bottom margin, we need to back up the containing
     // block's y-advance by our top margin so that it doesn't get
     // counted twice. Note that here we're allowing the line's bounds
     // to become different from the block's position; we do this
     // because the containing block will place the next line at the
     // line's YMost, and it must place the next line at a different
     // point from where this empty block will be.
     backupContainingBlockAdvance = mTopMargin.get();
   }
   // See if the frame fit. If it's the first frame or empty then it
   // always fits. If the height is unconstrained then it always fits,
   // even if there's some sort of integer overflow that makes y +
   // mMetrics.Height() appear to go beyond the available height.
   if (!empty && !aForceFit && mSpace.height != NS_UNCONSTRAINEDSIZE) {
     nscoord yMost = position.y - backupContainingBlockAdvance + mMetrics.Height();
     if (yMost > mSpace.YMost()) {
       // didn't fit, we must acquit.
       mFrame->DidReflow(mPresContext, &aReflowState, nsDidReflowStatus::FINISHED);
       return false;
     }
   }
   aLine->SetBounds(aReflowState.GetWritingMode(),
                    nsRect(position.x,
                           position.y - backupContainingBlockAdvance,
                           mMetrics.Width(),
                           mMetrics.Height()),
                    aContainerWidth);
   aReflowState.ApplyRelativePositioning(&position);
   // Now place the frame and complete the reflow process
   nsContainerFrame::FinishReflowChild(mFrame, mPresContext, mMetrics,
                                       &aReflowState, position.x, position.y, 0);
   aOverflowAreas = mMetrics.mOverflowAreas + position;
   return true;
 }

The Tor Browser / annotate

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

layout/generic/nsBlockReflowContext.cpp