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Mypal/layout/generic/nsFloatManager.cpp

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/* -*- 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->GetProperty(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();
if (region.IsEqualEdges(rect)) {
aFloat->DeleteProperty(FloatRegionProperty());
}
else {
nsMargin* storedMargin = aFloat->GetProperty(FloatRegionProperty());
if (!storedMargin) {
storedMargin = new nsMargin();
aFloat->SetProperty(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;
}
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