diff options
Diffstat (limited to 'layout/generic/nsFloatManager.cpp')
| -rw-r--r-- | layout/generic/nsFloatManager.cpp | 603 |
1 files changed, 603 insertions, 0 deletions
diff --git a/layout/generic/nsFloatManager.cpp b/layout/generic/nsFloatManager.cpp new file mode 100644 index 000000000..2c0ff1f38 --- /dev/null +++ b/layout/generic/nsFloatManager.cpp @@ -0,0 +1,603 @@ +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 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 manages rules for positioning floats */ + +#include "nsFloatManager.h" + +#include <algorithm> + +#include "mozilla/ReflowInput.h" +#include "nsBlockFrame.h" +#include "nsError.h" +#include "nsIPresShell.h" +#include "nsMemory.h" + +using namespace mozilla; + +int32_t nsFloatManager::sCachedFloatManagerCount = 0; +void* nsFloatManager::sCachedFloatManagers[NS_FLOAT_MANAGER_CACHE_SIZE]; + +///////////////////////////////////////////////////////////////////////////// + +// PresShell Arena allocate callback (for nsIntervalSet use below) +static void* +PSArenaAllocCB(size_t aSize, void* aClosure) +{ + return static_cast<nsIPresShell*>(aClosure)->AllocateMisc(aSize); +} + +// PresShell Arena free callback (for nsIntervalSet use below) +static void +PSArenaFreeCB(size_t aSize, void* aPtr, void* aClosure) +{ + static_cast<nsIPresShell*>(aClosure)->FreeMisc(aSize, aPtr); +} + +///////////////////////////////////////////////////////////////////////////// +// nsFloatManager + +nsFloatManager::nsFloatManager(nsIPresShell* aPresShell, + mozilla::WritingMode aWM) + : +#ifdef DEBUG + mWritingMode(aWM), +#endif + mLineLeft(0), mBlockStart(0), + mFloatDamage(PSArenaAllocCB, PSArenaFreeCB, aPresShell), + mPushedLeftFloatPastBreak(false), + mPushedRightFloatPastBreak(false), + mSplitLeftFloatAcrossBreak(false), + mSplitRightFloatAcrossBreak(false) +{ + MOZ_COUNT_CTOR(nsFloatManager); +} + +nsFloatManager::~nsFloatManager() +{ + MOZ_COUNT_DTOR(nsFloatManager); +} + +// static +void* nsFloatManager::operator new(size_t aSize) CPP_THROW_NEW +{ + if (sCachedFloatManagerCount > 0) { + // We have cached unused instances of this class, return a cached + // instance in stead of always creating a new one. + return sCachedFloatManagers[--sCachedFloatManagerCount]; + } + + // The cache is empty, this means we have to create a new instance using + // the global |operator new|. + return moz_xmalloc(aSize); +} + +void +nsFloatManager::operator delete(void* aPtr, size_t aSize) +{ + if (!aPtr) + return; + // This float manager is no longer used, if there's still room in + // the cache we'll cache this float manager, unless the layout + // module was already shut down. + + if (sCachedFloatManagerCount < NS_FLOAT_MANAGER_CACHE_SIZE && + sCachedFloatManagerCount >= 0) { + // There's still space in the cache for more instances, put this + // instance in the cache in stead of deleting it. + + sCachedFloatManagers[sCachedFloatManagerCount++] = aPtr; + return; + } + + // The cache is full, or the layout module has been shut down, + // delete this float manager. + free(aPtr); +} + + +/* static */ +void nsFloatManager::Shutdown() +{ + // The layout module is being shut down, clean up the cache and + // disable further caching. + + int32_t i; + + for (i = 0; i < sCachedFloatManagerCount; i++) { + void* floatManager = sCachedFloatManagers[i]; + if (floatManager) + free(floatManager); + } + + // Disable further caching. + sCachedFloatManagerCount = -1; +} + +#define CHECK_BLOCK_DIR(aWM) \ + NS_ASSERTION((aWM).GetBlockDir() == mWritingMode.GetBlockDir(), \ + "incompatible writing modes") + +nsFlowAreaRect +nsFloatManager::GetFlowArea(WritingMode aWM, nscoord aBOffset, + BandInfoType aInfoType, nscoord aBSize, + LogicalRect aContentArea, SavedState* aState, + const nsSize& aContainerSize) const +{ + CHECK_BLOCK_DIR(aWM); + NS_ASSERTION(aBSize >= 0, "unexpected max block size"); + NS_ASSERTION(aContentArea.ISize(aWM) >= 0, + "unexpected content area inline size"); + + nscoord blockStart = aBOffset + mBlockStart; + if (blockStart < nscoord_MIN) { + NS_WARNING("bad value"); + blockStart = nscoord_MIN; + } + + // Determine the last float that we should consider. + uint32_t floatCount; + if (aState) { + // Use the provided state. + floatCount = aState->mFloatInfoCount; + MOZ_ASSERT(floatCount <= mFloats.Length(), "bad state"); + } else { + // Use our current state. + floatCount = mFloats.Length(); + } + + // If there are no floats at all, or we're below the last one, return + // quickly. + if (floatCount == 0 || + (mFloats[floatCount-1].mLeftBEnd <= blockStart && + mFloats[floatCount-1].mRightBEnd <= blockStart)) { + return nsFlowAreaRect(aWM, aContentArea.IStart(aWM), aBOffset, + aContentArea.ISize(aWM), aBSize, false); + } + + nscoord blockEnd; + if (aBSize == nscoord_MAX) { + // This warning (and the two below) are possible to hit on pages + // with really large objects. + NS_WARNING_ASSERTION(aInfoType == BAND_FROM_POINT, "bad height"); + blockEnd = nscoord_MAX; + } else { + blockEnd = blockStart + aBSize; + if (blockEnd < blockStart || blockEnd > nscoord_MAX) { + NS_WARNING("bad value"); + blockEnd = nscoord_MAX; + } + } + nscoord lineLeft = mLineLeft + aContentArea.LineLeft(aWM, aContainerSize); + nscoord lineRight = mLineLeft + aContentArea.LineRight(aWM, aContainerSize); + if (lineRight < lineLeft) { + NS_WARNING("bad value"); + lineRight = lineLeft; + } + + // Walk backwards through the floats until we either hit the front of + // the list or we're above |blockStart|. + bool haveFloats = false; + for (uint32_t i = floatCount; i > 0; --i) { + const FloatInfo &fi = mFloats[i-1]; + if (fi.mLeftBEnd <= blockStart && fi.mRightBEnd <= blockStart) { + // There aren't any more floats that could intersect this band. + break; + } + if (fi.IsEmpty()) { + // For compatibility, ignore floats with empty rects, even though it + // disagrees with the spec. (We might want to fix this in the + // future, though.) + continue; + } + + nscoord floatBStart = fi.BStart(); + nscoord floatBEnd = fi.BEnd(); + if (blockStart < floatBStart && aInfoType == BAND_FROM_POINT) { + // This float is below our band. Shrink our band's height if needed. + if (floatBStart < blockEnd) { + blockEnd = floatBStart; + } + } + // If blockStart == blockEnd (which happens only with WIDTH_WITHIN_HEIGHT), + // we include floats that begin at our 0-height vertical area. We + // need to to this to satisfy the invariant that a + // WIDTH_WITHIN_HEIGHT call is at least as narrow on both sides as a + // BAND_WITHIN_POINT call beginning at its blockStart. + else if (blockStart < floatBEnd && + (floatBStart < blockEnd || + (floatBStart == blockEnd && blockStart == blockEnd))) { + // This float is in our band. + + // Shrink our band's height if needed. + if (floatBEnd < blockEnd && aInfoType == BAND_FROM_POINT) { + blockEnd = floatBEnd; + } + + // Shrink our band's width if needed. + StyleFloat floatStyle = fi.mFrame->StyleDisplay()->PhysicalFloats(aWM); + if (floatStyle == StyleFloat::Left) { + // A left float + nscoord lineRightEdge = fi.LineRight(); + if (lineRightEdge > lineLeft) { + lineLeft = lineRightEdge; + // Only set haveFloats to true if the float is inside our + // containing block. This matches the spec for what some + // callers want and disagrees for other callers, so we should + // probably provide better information at some point. + haveFloats = true; + } + } else { + // A right float + nscoord lineLeftEdge = fi.LineLeft(); + if (lineLeftEdge < lineRight) { + lineRight = lineLeftEdge; + // See above. + haveFloats = true; + } + } + } + } + + nscoord blockSize = (blockEnd == nscoord_MAX) ? + nscoord_MAX : (blockEnd - blockStart); + // convert back from LineLeft/Right to IStart + nscoord inlineStart = aWM.IsBidiLTR() + ? lineLeft - mLineLeft + : mLineLeft - lineRight + + LogicalSize(aWM, aContainerSize).ISize(aWM); + + return nsFlowAreaRect(aWM, inlineStart, blockStart - mBlockStart, + lineRight - lineLeft, blockSize, haveFloats); +} + +nsresult +nsFloatManager::AddFloat(nsIFrame* aFloatFrame, const LogicalRect& aMarginRect, + WritingMode aWM, const nsSize& aContainerSize) +{ + CHECK_BLOCK_DIR(aWM); + NS_ASSERTION(aMarginRect.ISize(aWM) >= 0, "negative inline size!"); + NS_ASSERTION(aMarginRect.BSize(aWM) >= 0, "negative block size!"); + + FloatInfo info(aFloatFrame, + aMarginRect.LineLeft(aWM, aContainerSize) + mLineLeft, + aMarginRect.BStart(aWM) + mBlockStart, + aMarginRect.ISize(aWM), + aMarginRect.BSize(aWM)); + + // Set mLeftBEnd and mRightBEnd. + if (HasAnyFloats()) { + FloatInfo &tail = mFloats[mFloats.Length() - 1]; + info.mLeftBEnd = tail.mLeftBEnd; + info.mRightBEnd = tail.mRightBEnd; + } else { + info.mLeftBEnd = nscoord_MIN; + info.mRightBEnd = nscoord_MIN; + } + StyleFloat floatStyle = aFloatFrame->StyleDisplay()->PhysicalFloats(aWM); + MOZ_ASSERT(floatStyle == StyleFloat::Left || floatStyle == StyleFloat::Right, + "Unexpected float style!"); + nscoord& sideBEnd = + floatStyle == StyleFloat::Left ? info.mLeftBEnd : info.mRightBEnd; + nscoord thisBEnd = info.BEnd(); + if (thisBEnd > sideBEnd) + sideBEnd = thisBEnd; + + if (!mFloats.AppendElement(info)) + return NS_ERROR_OUT_OF_MEMORY; + + return NS_OK; +} + +// static +LogicalRect +nsFloatManager::CalculateRegionFor(WritingMode aWM, + nsIFrame* aFloat, + const LogicalMargin& aMargin, + const nsSize& aContainerSize) +{ + // We consider relatively positioned frames at their original position. + LogicalRect region(aWM, nsRect(aFloat->GetNormalPosition(), + aFloat->GetSize()), + aContainerSize); + + // Float region includes its margin + region.Inflate(aWM, aMargin); + + // Don't store rectangles with negative margin-box width or height in + // the float manager; it can't deal with them. + if (region.ISize(aWM) < 0) { + // Preserve the right margin-edge for left floats and the left + // margin-edge for right floats + const nsStyleDisplay* display = aFloat->StyleDisplay(); + StyleFloat floatStyle = display->PhysicalFloats(aWM); + if ((StyleFloat::Left == floatStyle) == aWM.IsBidiLTR()) { + region.IStart(aWM) = region.IEnd(aWM); + } + region.ISize(aWM) = 0; + } + if (region.BSize(aWM) < 0) { + region.BSize(aWM) = 0; + } + return region; +} + +NS_DECLARE_FRAME_PROPERTY_DELETABLE(FloatRegionProperty, nsMargin) + +LogicalRect +nsFloatManager::GetRegionFor(WritingMode aWM, nsIFrame* aFloat, + const nsSize& aContainerSize) +{ + LogicalRect region = aFloat->GetLogicalRect(aWM, aContainerSize); + void* storedRegion = aFloat->Properties().Get(FloatRegionProperty()); + if (storedRegion) { + nsMargin margin = *static_cast<nsMargin*>(storedRegion); + region.Inflate(aWM, LogicalMargin(aWM, margin)); + } + return region; +} + +void +nsFloatManager::StoreRegionFor(WritingMode aWM, nsIFrame* aFloat, + const LogicalRect& aRegion, + const nsSize& aContainerSize) +{ + nsRect region = aRegion.GetPhysicalRect(aWM, aContainerSize); + nsRect rect = aFloat->GetRect(); + FrameProperties props = aFloat->Properties(); + if (region.IsEqualEdges(rect)) { + props.Delete(FloatRegionProperty()); + } + else { + nsMargin* storedMargin = props.Get(FloatRegionProperty()); + if (!storedMargin) { + storedMargin = new nsMargin(); + props.Set(FloatRegionProperty(), storedMargin); + } + *storedMargin = region - rect; + } +} + +nsresult +nsFloatManager::RemoveTrailingRegions(nsIFrame* aFrameList) +{ + if (!aFrameList) { + return NS_OK; + } + // This could be a good bit simpler if we could guarantee that the + // floats given were at the end of our list, so we could just search + // for the head of aFrameList. (But we can't; + // layout/reftests/bugs/421710-1.html crashes.) + nsTHashtable<nsPtrHashKey<nsIFrame> > frameSet(1); + + for (nsIFrame* f = aFrameList; f; f = f->GetNextSibling()) { + frameSet.PutEntry(f); + } + + uint32_t newLength = mFloats.Length(); + while (newLength > 0) { + if (!frameSet.Contains(mFloats[newLength - 1].mFrame)) { + break; + } + --newLength; + } + mFloats.TruncateLength(newLength); + +#ifdef DEBUG + for (uint32_t i = 0; i < mFloats.Length(); ++i) { + NS_ASSERTION(!frameSet.Contains(mFloats[i].mFrame), + "Frame region deletion was requested but we couldn't delete it"); + } +#endif + + return NS_OK; +} + +void +nsFloatManager::PushState(SavedState* aState) +{ + NS_PRECONDITION(aState, "Need a place to save state"); + + // This is a cheap push implementation, which + // only saves the (x,y) and last frame in the mFrameInfoMap + // which is enough info to get us back to where we should be + // when pop is called. + // + // This push/pop mechanism is used to undo any + // floats that were added during the unconstrained reflow + // in nsBlockReflowContext::DoReflowBlock(). (See bug 96736) + // + // It should also be noted that the state for mFloatDamage is + // intentionally not saved or restored in PushState() and PopState(), + // since that could lead to bugs where damage is missed/dropped when + // we move from position A to B (during the intermediate incremental + // reflow mentioned above) and then from B to C during the subsequent + // reflow. In the typical case A and C will be the same, but not always. + // Allowing mFloatDamage to accumulate the damage incurred during both + // reflows ensures that nothing gets missed. + aState->mLineLeft = mLineLeft; + aState->mBlockStart = mBlockStart; + aState->mPushedLeftFloatPastBreak = mPushedLeftFloatPastBreak; + aState->mPushedRightFloatPastBreak = mPushedRightFloatPastBreak; + aState->mSplitLeftFloatAcrossBreak = mSplitLeftFloatAcrossBreak; + aState->mSplitRightFloatAcrossBreak = mSplitRightFloatAcrossBreak; + aState->mFloatInfoCount = mFloats.Length(); +} + +void +nsFloatManager::PopState(SavedState* aState) +{ + NS_PRECONDITION(aState, "No state to restore?"); + + mLineLeft = aState->mLineLeft; + mBlockStart = aState->mBlockStart; + mPushedLeftFloatPastBreak = aState->mPushedLeftFloatPastBreak; + mPushedRightFloatPastBreak = aState->mPushedRightFloatPastBreak; + mSplitLeftFloatAcrossBreak = aState->mSplitLeftFloatAcrossBreak; + mSplitRightFloatAcrossBreak = aState->mSplitRightFloatAcrossBreak; + + NS_ASSERTION(aState->mFloatInfoCount <= mFloats.Length(), + "somebody misused PushState/PopState"); + mFloats.TruncateLength(aState->mFloatInfoCount); +} + +nscoord +nsFloatManager::GetLowestFloatTop() const +{ + if (mPushedLeftFloatPastBreak || mPushedRightFloatPastBreak) { + return nscoord_MAX; + } + if (!HasAnyFloats()) { + return nscoord_MIN; + } + return mFloats[mFloats.Length() -1].BStart() - mBlockStart; +} + +#ifdef DEBUG_FRAME_DUMP +void +DebugListFloatManager(const nsFloatManager *aFloatManager) +{ + aFloatManager->List(stdout); +} + +nsresult +nsFloatManager::List(FILE* out) const +{ + if (!HasAnyFloats()) + return NS_OK; + + for (uint32_t i = 0; i < mFloats.Length(); ++i) { + const FloatInfo &fi = mFloats[i]; + fprintf_stderr(out, "Float %u: frame=%p rect={%d,%d,%d,%d} BEnd={l:%d, r:%d}\n", + i, static_cast<void*>(fi.mFrame), + fi.LineLeft(), fi.BStart(), fi.ISize(), fi.BSize(), + fi.mLeftBEnd, fi.mRightBEnd); + } + return NS_OK; +} +#endif + +nscoord +nsFloatManager::ClearFloats(nscoord aBCoord, StyleClear aBreakType, + uint32_t aFlags) const +{ + if (!(aFlags & DONT_CLEAR_PUSHED_FLOATS) && ClearContinues(aBreakType)) { + return nscoord_MAX; + } + if (!HasAnyFloats()) { + return aBCoord; + } + + nscoord blockEnd = aBCoord + mBlockStart; + + const FloatInfo &tail = mFloats[mFloats.Length() - 1]; + switch (aBreakType) { + case StyleClear::Both: + blockEnd = std::max(blockEnd, tail.mLeftBEnd); + blockEnd = std::max(blockEnd, tail.mRightBEnd); + break; + case StyleClear::Left: + blockEnd = std::max(blockEnd, tail.mLeftBEnd); + break; + case StyleClear::Right: + blockEnd = std::max(blockEnd, tail.mRightBEnd); + break; + default: + // Do nothing + break; + } + + blockEnd -= mBlockStart; + + return blockEnd; +} + +bool +nsFloatManager::ClearContinues(StyleClear aBreakType) const +{ + return ((mPushedLeftFloatPastBreak || mSplitLeftFloatAcrossBreak) && + (aBreakType == StyleClear::Both || + aBreakType == StyleClear::Left)) || + ((mPushedRightFloatPastBreak || mSplitRightFloatAcrossBreak) && + (aBreakType == StyleClear::Both || + aBreakType == StyleClear::Right)); +} + +///////////////////////////////////////////////////////////////////////////// +// FloatInfo + +nsFloatManager::FloatInfo::FloatInfo(nsIFrame* aFrame, + nscoord aLineLeft, nscoord aBStart, + nscoord aISize, nscoord aBSize) + : mFrame(aFrame) + , mRect(aLineLeft, aBStart, aISize, aBSize) +{ + MOZ_COUNT_CTOR(nsFloatManager::FloatInfo); +} + +#ifdef NS_BUILD_REFCNT_LOGGING +nsFloatManager::FloatInfo::FloatInfo(const FloatInfo& aOther) + : mFrame(aOther.mFrame), + mLeftBEnd(aOther.mLeftBEnd), + mRightBEnd(aOther.mRightBEnd), + mRect(aOther.mRect) +{ + MOZ_COUNT_CTOR(nsFloatManager::FloatInfo); +} + +nsFloatManager::FloatInfo::~FloatInfo() +{ + MOZ_COUNT_DTOR(nsFloatManager::FloatInfo); +} +#endif + +//---------------------------------------------------------------------- + +nsAutoFloatManager::~nsAutoFloatManager() +{ + // Restore the old float manager in the reflow input if necessary. + if (mNew) { +#ifdef DEBUG + if (nsBlockFrame::gNoisyFloatManager) { + printf("restoring old float manager %p\n", mOld); + } +#endif + + mReflowInput.mFloatManager = mOld; + +#ifdef DEBUG + if (nsBlockFrame::gNoisyFloatManager) { + if (mOld) { + mReflowInput.mFrame->ListTag(stdout); + printf(": float manager %p after reflow\n", mOld); + mOld->List(stdout); + } + } +#endif + + delete mNew; + } +} + +void +nsAutoFloatManager::CreateFloatManager(nsPresContext *aPresContext) +{ + // Create a new float manager and install it in the reflow + // input. `Remember' the old float manager so we can restore it + // later. + mNew = new nsFloatManager(aPresContext->PresShell(), + mReflowInput.GetWritingMode()); + +#ifdef DEBUG + if (nsBlockFrame::gNoisyFloatManager) { + printf("constructed new float manager %p (replacing %p)\n", + mNew, mReflowInput.mFloatManager); + } +#endif + + // Set the float manager in the existing reflow input. + mOld = mReflowInput.mFloatManager; + mReflowInput.mFloatManager = mNew; +} |