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pjs/layout/generic/nsSpaceManager.cpp

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is mozilla.org code.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 1998
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Pierre Phaneuf <pp@ludusdesign.com>
*
* Alternatively, the contents of this file may be used under the terms of
* either of the GNU General Public License Version 2 or later (the "GPL"),
* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
/*
* class that manages regions of 2-D space, originally designed
* generally but actually specific to space occupied by floats
*/
#include "nsSpaceManager.h"
#include "nsPoint.h"
#include "nsRect.h"
#include "nsSize.h"
#include <stdlib.h>
#include "nsVoidArray.h"
#include "nsIFrame.h"
#include "nsString.h"
#include "nsIPresShell.h"
#include "nsMemory.h"
#include "nsHTMLReflowState.h"
#include "nsHashSets.h"
#ifdef DEBUG
#include "nsIFrameDebug.h"
#endif
/////////////////////////////////////////////////////////////////////////////
// BandList
PRInt32 nsSpaceManager::sCachedSpaceManagerCount = 0;
void* nsSpaceManager::sCachedSpaceManagers[NS_SPACE_MANAGER_CACHE_SIZE];
#define NSCOORD_MIN (-2147483647 - 1) /* minimum signed value */
nsSpaceManager::BandList::BandList()
: nsSpaceManager::BandRect(NSCOORD_MIN, NSCOORD_MIN, NSCOORD_MIN, NSCOORD_MIN, (nsIFrame*)nsnull)
{
PR_INIT_CLIST(this);
mNumFrames = 0;
}
void
nsSpaceManager::BandList::Clear()
{
if (!IsEmpty()) {
BandRect* bandRect = Head();
while (bandRect != this) {
BandRect* nxt = bandRect->Next();
delete bandRect;
bandRect = nxt;
}
PR_INIT_CLIST(this);
}
}
/////////////////////////////////////////////////////////////////////////////
// PresShell Arena allocate callback (for nsIntervalSet use below)
PR_STATIC_CALLBACK(void*)
PSArenaAllocCB(size_t aSize, void* aClosure)
{
return NS_STATIC_CAST(nsIPresShell*, aClosure)->AllocateFrame(aSize);
}
// PresShell Arena free callback (for nsIntervalSet use below)
PR_STATIC_CALLBACK(void)
PSArenaFreeCB(size_t aSize, void* aPtr, void* aClosure)
{
NS_STATIC_CAST(nsIPresShell*, aClosure)->FreeFrame(aSize, aPtr);
}
/////////////////////////////////////////////////////////////////////////////
// nsSpaceManager
nsSpaceManager::nsSpaceManager(nsIPresShell* aPresShell, nsIFrame* aFrame)
: mFrame(aFrame),
mLowestTop(NSCOORD_MIN),
mFloatDamage(PSArenaAllocCB, PSArenaFreeCB, aPresShell),
mHaveCachedLeftYMost(PR_TRUE),
mHaveCachedRightYMost(PR_TRUE),
mMaximalLeftYMost(0),
mMaximalRightYMost(0)
{
MOZ_COUNT_CTOR(nsSpaceManager);
mX = mY = 0;
mFrameInfoMap = nsnull;
}
void
nsSpaceManager::ClearFrameInfo()
{
while (mFrameInfoMap) {
FrameInfo* next = mFrameInfoMap->mNext;
delete mFrameInfoMap;
mFrameInfoMap = next;
}
}
nsSpaceManager::~nsSpaceManager()
{
MOZ_COUNT_DTOR(nsSpaceManager);
mBandList.Clear();
ClearFrameInfo();
}
// static
void* nsSpaceManager::operator new(size_t aSize) CPP_THROW_NEW
{
if (sCachedSpaceManagerCount > 0) {
// We have cached unused instances of this class, return a cached
// instance in stead of always creating a new one.
return sCachedSpaceManagers[--sCachedSpaceManagerCount];
}
// The cache is empty, this means we haveto create a new instance using
// the global |operator new|.
return nsMemory::Alloc(aSize);
}
void
nsSpaceManager::operator delete(void* aPtr, size_t aSize)
{
if (!aPtr)
return;
// This space manager is no longer used, if there's still room in
// the cache we'll cache this space manager, unless the layout
// module was already shut down.
if (sCachedSpaceManagerCount < NS_SPACE_MANAGER_CACHE_SIZE &&
sCachedSpaceManagerCount >= 0) {
// There's still space in the cache for more instances, put this
// instance in the cache in stead of deleting it.
sCachedSpaceManagers[sCachedSpaceManagerCount++] = aPtr;
return;
}
// The cache is full, or the layout module has been shut down,
// delete this space manager.
nsMemory::Free(aPtr);
}
/* static */
void nsSpaceManager::Shutdown()
{
// The layout module is being shut down, clean up the cache and
// disable further caching.
PRInt32 i;
for (i = 0; i < sCachedSpaceManagerCount; i++) {
void* spaceManager = sCachedSpaceManagers[i];
if (spaceManager)
nsMemory::Free(spaceManager);
}
// Disable further caching.
sCachedSpaceManagerCount = -1;
}
PRBool
nsSpaceManager::XMost(nscoord& aXMost) const
{
nscoord xMost = 0;
for (FrameInfo* fi = mFrameInfoMap; fi; fi = fi->mNext) {
xMost = PR_MAX(xMost, fi->mRect.XMost());
}
aXMost = xMost;
return !mBandList.IsEmpty();
}
PRBool
nsSpaceManager::YMost(nscoord& aYMost) const
{
PRBool result;
if (mBandList.IsEmpty()) {
aYMost = 0;
result = PR_FALSE;
} else {
BandRect* lastRect = mBandList.Tail();
aYMost = lastRect->mBottom;
result = PR_TRUE;
}
return result;
}
/**
* Internal function that returns the list of available and unavailable space
* within the band
*
* @param aBand the first rect in the band
* @param aY the y-offset in world coordinates
* @param aMaxSize the size to use to constrain the band data
* @param aAvailableBand
*/
nsresult
nsSpaceManager::GetBandAvailableSpace(const BandRect* aBand,
nscoord aY,
const nsSize& aMaxSize,
nsBandData& aBandData) const
{
nscoord topOfBand = aBand->mTop;
nscoord localY = aY - mY;
nscoord height = PR_MIN(aBand->mBottom - aY, aMaxSize.height);
nsBandTrapezoid* trapezoid = aBandData.mTrapezoids;
nscoord rightEdge = mX + aMaxSize.width;
// Initialize the band data
aBandData.mCount = 0;
// Skip any rectangles that are to the left of the local coordinate space
while (aBand->mTop == topOfBand) {
if (aBand->mRight > mX) {
break;
}
// Get the next rect in the band
aBand = aBand->Next();
}
// This is used to track the current x-location within the band. This is in
// world coordinates
nscoord left = mX;
// Process the remaining rectangles that are within the clip width
while ((aBand->mTop == topOfBand) && (aBand->mLeft < rightEdge)) {
// Compare the left edge of the occupied space with the current left
// coordinate
if (aBand->mLeft > left) {
// The rect is to the right of our current left coordinate, so we've
// found some available space
if (aBandData.mCount >= aBandData.mSize) {
// Not enough space in the array of trapezoids
aBandData.mCount += 2 * aBand->Length() + 2; // estimate the number needed
return NS_ERROR_FAILURE;
}
trapezoid->mState = nsBandTrapezoid::Available;
trapezoid->mFrame = nsnull;
// Assign the trapezoid a rectangular shape. The trapezoid must be in the
// local coordinate space, so convert the current left coordinate
*trapezoid = nsRect(left - mX, localY, aBand->mLeft - left, height);
// Move to the next output rect
trapezoid++;
aBandData.mCount++;
}
// The rect represents unavailable space, so add another trapezoid
if (aBandData.mCount >= aBandData.mSize) {
// Not enough space in the array of trapezoids
aBandData.mCount += 2 * aBand->Length() + 1; // estimate the number needed
return NS_ERROR_FAILURE;
}
if (1 == aBand->mNumFrames) {
trapezoid->mState = nsBandTrapezoid::Occupied;
trapezoid->mFrame = aBand->mFrame;
} else {
NS_ASSERTION(aBand->mNumFrames > 1, "unexpected frame count");
trapezoid->mState = nsBandTrapezoid::OccupiedMultiple;
trapezoid->mFrames = aBand->mFrames;
}
nscoord x = aBand->mLeft;
// The first band can straddle the clip rect
if (x < mX) {
// Clip the left edge
x = mX;
}
// Assign the trapezoid a rectangular shape. The trapezoid must be in the
// local coordinate space, so convert the rects's left coordinate
*trapezoid = nsRect(x - mX, localY, aBand->mRight - x, height);
// Move to the next output rect
trapezoid++;
aBandData.mCount++;
// Adjust our current x-location within the band
left = aBand->mRight;
// Move to the next rect within the band
aBand = aBand->Next();
}
// No more rects left in the band. If we haven't yet reached the right edge,
// then all the remaining space is available
if (left < rightEdge) {
if (aBandData.mCount >= aBandData.mSize) {
// Not enough space in the array of trapezoids
aBandData.mCount++;
return NS_ERROR_FAILURE;
}
trapezoid->mState = nsBandTrapezoid::Available;
trapezoid->mFrame = nsnull;
// Assign the trapezoid a rectangular shape. The trapezoid must be in the
// local coordinate space, so convert the current left coordinate
*trapezoid = nsRect(left - mX, localY, rightEdge - left, height);
aBandData.mCount++;
}
return NS_OK;
}
nsresult
nsSpaceManager::GetBandData(nscoord aYOffset,
const nsSize& aMaxSize,
nsBandData& aBandData) const
{
NS_PRECONDITION(aBandData.mSize >= 1, "bad band data");
nsresult result = NS_OK;
// Convert the y-offset to world coordinates
nscoord y = mY + aYOffset;
// If there are no unavailable rects or the offset is below the bottommost
// band, then all the space is available
nscoord yMost;
nscoord maxHeight = aMaxSize.height == NS_UNCONSTRAINEDSIZE ? NS_UNCONSTRAINEDSIZE
: PR_MAX(0, aMaxSize.height - aYOffset);
if (!YMost(yMost) || (y >= yMost)) {
// All the requested space is available
aBandData.mCount = 1;
aBandData.mTrapezoids[0] = nsRect(0, aYOffset, aMaxSize.width, maxHeight);
aBandData.mTrapezoids[0].mState = nsBandTrapezoid::Available;
aBandData.mTrapezoids[0].mFrame = nsnull;
} else {
// Find the first band that contains the y-offset or is below the y-offset
NS_ASSERTION(!mBandList.IsEmpty(), "no bands");
BandRect* band = mBandList.Head();
aBandData.mCount = 0;
while (nsnull != band) {
if (band->mTop > y) {
// The band is below the y-offset. The area between the y-offset and
// the top of the band is available
aBandData.mCount = 1;
aBandData.mTrapezoids[0] =
nsRect(0, aYOffset, aMaxSize.width, PR_MIN(band->mTop - y, maxHeight));
aBandData.mTrapezoids[0].mState = nsBandTrapezoid::Available;
aBandData.mTrapezoids[0].mFrame = nsnull;
break;
} else if (y < band->mBottom) {
// The band contains the y-offset. Return a list of available and
// unavailable rects within the band
return GetBandAvailableSpace(band, y, nsSize(aMaxSize.width, maxHeight), aBandData);
} else {
// Skip to the next band
band = GetNextBand(band);
}
}
}
NS_POSTCONDITION(aBandData.mCount > 0, "unexpected band data count");
return result;
}
/**
* Skips to the start of the next band.
*
* @param aBandRect A rect within the band
* @returns The start of the next band, or nsnull of this is the last band.
*/
nsSpaceManager::BandRect*
nsSpaceManager::GetNextBand(const BandRect* aBandRect) const
{
nscoord topOfBand = aBandRect->mTop;
aBandRect = aBandRect->Next();
while (aBandRect != &mBandList) {
// Check whether this rect is part of the same band
if (aBandRect->mTop != topOfBand) {
// We found the start of the next band
return (BandRect*)aBandRect;
}
aBandRect = aBandRect->Next();
}
// No bands left
return nsnull;
}
/**
* Divides the current band into two vertically
*
* @param aBandRect the first rect in the band
* @param aBottom where to split the band. This becomes the bottom of the top
* part
*/
void
nsSpaceManager::DivideBand(BandRect* aBandRect, nscoord aBottom)
{
NS_PRECONDITION(aBottom < aBandRect->mBottom, "bad height");
nscoord topOfBand = aBandRect->mTop;
BandRect* nextBand = GetNextBand(aBandRect);
if (nsnull == nextBand) {
nextBand = (BandRect*)&mBandList;
}
while (topOfBand == aBandRect->mTop) {
// Split the band rect into two vertically
BandRect* bottomBandRect = aBandRect->SplitVertically(aBottom);
// Insert the new bottom part
nextBand->InsertBefore(bottomBandRect);
// Move to the next rect in the band
aBandRect = aBandRect->Next();
}
}
PRBool
nsSpaceManager::CanJoinBands(BandRect* aBand, BandRect* aPrevBand)
{
PRBool result;
nscoord topOfBand = aBand->mTop;
nscoord topOfPrevBand = aPrevBand->mTop;
// The bands can be joined if:
// - they're adjacent
// - they have the same number of rects
// - each rect has the same left and right edge as its corresponding rect, and
// the rects are occupied by the same frames
if (aPrevBand->mBottom == aBand->mTop) {
// Compare each of the rects in the two bands
while (PR_TRUE) {
if ((aBand->mLeft != aPrevBand->mLeft) || (aBand->mRight != aPrevBand->mRight)) {
// The rects have different edges
result = PR_FALSE;
break;
}
if (!aBand->HasSameFrameList(aPrevBand)) {
// The rects are occupied by different frames
result = PR_FALSE;
break;
}
// Move to the next rects within the bands
aBand = aBand->Next();
aPrevBand = aPrevBand->Next();
// Have we reached the end of either band?
PRBool endOfBand = aBand->mTop != topOfBand;
PRBool endOfPrevBand = aPrevBand->mTop != topOfPrevBand;
if (endOfBand || endOfPrevBand) {
result = endOfBand & endOfPrevBand;
break; // all done
}
}
} else {
// The bands aren't adjacent
result = PR_FALSE;
}
return result;
}
/**
* Tries to join the two adjacent bands. Returns PR_TRUE if successful and
* PR_FALSE otherwise
*
* If the two bands are joined, the previous band is the band that's deleted
*/
PRBool
nsSpaceManager::JoinBands(BandRect* aBand, BandRect* aPrevBand)
{
if (CanJoinBands(aBand, aPrevBand)) {
BandRect* startOfNextBand = aBand;
while (aPrevBand != startOfNextBand) {
// Adjust the top of the band we're keeping, and then move to the next
// rect within the band
aBand->mTop = aPrevBand->mTop;
aBand = aBand->Next();
// Delete the rect from the previous band
BandRect* next = aPrevBand->Next();
aPrevBand->Remove();
delete aPrevBand;
aPrevBand = next;
}
return PR_TRUE;
}
return PR_FALSE;
}
/**
* Adds a new rect to a band.
*
* @param aBand the first rect in the band
* @param aBandRect the band rect to add to the band
*/
void
nsSpaceManager::AddRectToBand(BandRect* aBand, BandRect* aBandRect)
{
NS_PRECONDITION((aBand->mTop == aBandRect->mTop) &&
(aBand->mBottom == aBandRect->mBottom), "bad band");
NS_PRECONDITION(1 == aBandRect->mNumFrames, "shared band rect");
nscoord topOfBand = aBand->mTop;
// Figure out where in the band horizontally to insert the rect
do {
// Compare the left edge of the new rect with the left edge of the existing
// rect
if (aBandRect->mLeft < aBand->mLeft) {
// The new rect's left edge is to the left of the existing rect's left edge.
// Could be any of these cases (N is new rect, E is existing rect):
//
// Case 1: left-of Case 2: overlaps Case 3: N.contains(E)
// --------------- ---------------- ---------------------
// +-----+ +-----+ +-----+ +---------+
// | N | | E | | N | | N |
// +-----+ +-----+ +-----+ +---------+
// +-----+ +---+
// | E | | E |
// +-----+ +---+
//
// Do the two rectangles overlap?
if (aBandRect->mRight <= aBand->mLeft) {
// No, the new rect is completely to the left of the existing rect
// (case #1). Insert a new rect
aBand->InsertBefore(aBandRect);
return;
}
// Yes, they overlap. Compare the right edges.
if (aBandRect->mRight > aBand->mRight) {
// The new rect's right edge is to the right of the existing rect's
// right edge (case #3). Split the new rect
BandRect* r1 = aBandRect->SplitHorizontally(aBand->mLeft);
// Insert the part of the new rect that's to the left of the existing
// rect as a new band rect
aBand->InsertBefore(aBandRect);
// Continue below with the part that overlaps the existing rect
aBandRect = r1;
} else {
if (aBand->mRight > aBandRect->mRight) {
// The existing rect extends past the new rect (case #2). Split the
// existing rect
BandRect* r1 = aBand->SplitHorizontally(aBandRect->mRight);
// Insert the new right half of the existing rect
aBand->InsertAfter(r1);
}
// Insert the part of the new rect that's to the left of the existing
// rect
aBandRect->mRight = aBand->mLeft;
aBand->InsertBefore(aBandRect);
// Mark the existing rect as shared
aBand->AddFrame(aBandRect->mFrame);
return;
}
}
if (aBandRect->mLeft > aBand->mLeft) {
// The new rect's left edge is to the right of the existing rect's left
// edge. Could be any one of these cases:
//
// Case 4: right-of Case 5: overlaps Case 6: E.Contains(N)
// --------------- ---------------- ---------------------
// +-----+ +-----+ +-----+ +------------+
// | E | | N | | E | | E |
// +-----+ +-----+ +-----+ +------------+
// +-----+ +-----+
// | N | | N |
// +-----+ +-----+
//
if (aBandRect->mLeft >= aBand->mRight) {
// The new rect is to the right of the existing rect (case #4), so move
// to the next rect in the band
aBand = aBand->Next();
continue;
}
// The rects overlap, so divide the existing rect into two rects: the
// part to the left of the new rect, and the part that overlaps
BandRect* r1 = aBand->SplitHorizontally(aBandRect->mLeft);
// Insert the new right half of the existing rect, and make it the current
// rect
aBand->InsertAfter(r1);
aBand = r1;
}
// At this point the left edge of the new rect is the same as the left edge
// of the existing rect
NS_ASSERTION(aBandRect->mLeft == aBand->mLeft, "unexpected rect");
// Compare which rect is wider, the new rect or the existing rect
if (aBand->mRight > aBandRect->mRight) {
// The existing rect is wider (case #6). Divide the existing rect into
// two rects: the part that overlaps, and the part to the right of the
// new rect
BandRect* r1 = aBand->SplitHorizontally(aBandRect->mRight);
// Insert the new right half of the existing rect
aBand->InsertAfter(r1);
// Mark the overlap as being shared
aBand->AddFrame(aBandRect->mFrame);
return;
} else {
// Indicate the frames share the existing rect
aBand->AddFrame(aBandRect->mFrame);
if (aBand->mRight == aBandRect->mRight) {
// The new and existing rect have the same right edge. We're all done,
// and the new band rect is no longer needed
delete aBandRect;
return;
} else {
// The new rect is wider than the existing rect (cases #5). Set the
// new rect to be the overhang, and move to the next rect within the band
aBandRect->mLeft = aBand->mRight;
aBand = aBand->Next();
continue;
}
}
} while (aBand->mTop == topOfBand);
// Insert a new rect
aBand->InsertBefore(aBandRect);
}
// When comparing a rect to a band there are seven cases to consider.
// 'R' is the rect and 'B' is the band.
//
// Case 1 Case 2 Case 3 Case 4
// ------ ------ ------ ------
// +-----+ +-----+ +-----+ +-----+
// | R | | R | +-----+ +-----+ | | | |
// +-----+ +-----+ | | | R | | B | | B |
// +-----+ | B | +-----+ | | +-----+ | |
// | | | | +-----+ | R | +-----+
// | B | +-----+ +-----+
// | |
// +-----+
//
//
//
// Case 5 Case 6 Case 7
// ------ ------ ------
// +-----+ +-----+ +-----+ +-----+
// | | | R | | B | | | +-----+
// | B | +-----+ +-----+ | R | | B |
// | | | | +-----+
// +-----+ +-----+
// +-----+
// | R |
// +-----+
//
void
nsSpaceManager::InsertBandRect(BandRect* aBandRect)
{
// If there are no existing bands or this rect is below the bottommost
// band, then add a new band
nscoord yMost;
if (!YMost(yMost) || (aBandRect->mTop >= yMost)) {
mBandList.Append(aBandRect);
return;
}
// Examine each band looking for a band that intersects this rect
NS_ASSERTION(!mBandList.IsEmpty(), "no bands");
BandRect* band = mBandList.Head();
while (nsnull != band) {
// Compare the top edge of this rect with the top edge of the band
if (aBandRect->mTop < band->mTop) {
// The top edge of the rect is above the top edge of the band.
// Is there any overlap?
if (aBandRect->mBottom <= band->mTop) {
// Case #1. This rect is completely above the band, so insert a
// new band before the current band
band->InsertBefore(aBandRect);
break; // we're all done
}
// Case #2 and case #7. Divide this rect, creating a new rect for
// the part that's above the band
BandRect* bandRect1 = new BandRect(aBandRect->mLeft, aBandRect->mTop,
aBandRect->mRight, band->mTop,
aBandRect->mFrame);
// Insert bandRect1 as a new band
band->InsertBefore(bandRect1);
// Modify this rect to exclude the part above the band
aBandRect->mTop = band->mTop;
} else if (aBandRect->mTop > band->mTop) {
// The top edge of the rect is below the top edge of the band. Is there
// any overlap?
if (aBandRect->mTop >= band->mBottom) {
// Case #5. This rect is below the current band. Skip to the next band
band = GetNextBand(band);
continue;
}
// Case #3 and case #4. Divide the current band into two bands with the
// top band being the part that's above the rect
DivideBand(band, aBandRect->mTop);
// Skip to the bottom band that we just created
band = GetNextBand(band);
}
// At this point the rect and the band should have the same y-offset
NS_ASSERTION(aBandRect->mTop == band->mTop, "unexpected band");
// Is the band higher than the rect?
if (band->mBottom > aBandRect->mBottom) {
// Divide the band into two bands with the top band the same height
// as the rect
DivideBand(band, aBandRect->mBottom);
}
if (aBandRect->mBottom == band->mBottom) {
// Add the rect to the band
AddRectToBand(band, aBandRect);
break;
} else {
// Case #4 and case #7. The rect contains the band vertically. Divide
// the rect, creating a new rect for the part that overlaps the band
BandRect* bandRect1 = new BandRect(aBandRect->mLeft, aBandRect->mTop,
aBandRect->mRight, band->mBottom,
aBandRect->mFrame);
// Add bandRect1 to the band
AddRectToBand(band, bandRect1);
// Modify aBandRect to be the part below the band
aBandRect->mTop = band->mBottom;
// Continue with the next band
band = GetNextBand(band);
if (nsnull == band) {
// Append a new bottommost band
mBandList.Append(aBandRect);
break;
}
}
}
}
nsresult
nsSpaceManager::AddRectRegion(nsIFrame* aFrame, const nsRect& aUnavailableSpace)
{
NS_PRECONDITION(nsnull != aFrame, "null frame");
#ifdef DEBUG
// See if there is already a region associated with aFrame
NS_ASSERTION(!GetFrameInfoFor(aFrame),
"aFrame is already associated with a region");
#endif
// Convert the frame to world coordinates
nsRect rect(aUnavailableSpace.x + mX, aUnavailableSpace.y + mY,
aUnavailableSpace.width, aUnavailableSpace.height);
if (rect.y > mLowestTop)
mLowestTop = rect.y;
// Create a frame info structure
FrameInfo* frameInfo = CreateFrameInfo(aFrame, rect);
if (nsnull == frameInfo) {
return NS_ERROR_OUT_OF_MEMORY;
}
if (aUnavailableSpace.height <= 0)
return NS_OK;
// Allocate a band rect
BandRect* bandRect = new BandRect(rect.x, rect.y, rect.XMost(), rect.YMost(), aFrame);
if (nsnull == bandRect) {
return NS_ERROR_OUT_OF_MEMORY;
}
// Insert the band rect
InsertBandRect(bandRect);
return NS_OK;
}
nsresult
nsSpaceManager::RemoveTrailingRegions(nsIFrame* aFrameList) {
nsVoidHashSet frameSet;
frameSet.Init(1);
for (nsIFrame* f = aFrameList; f; f = f->GetNextSibling()) {
frameSet.Put(f);
}
// Pop frame regions off as long as they're in the set of frames to
// remove
while (mFrameInfoMap && frameSet.Contains(mFrameInfoMap->mFrame)) {
RemoveRegion(mFrameInfoMap->mFrame);
}
#ifdef DEBUG
for (FrameInfo* frameInfo = mFrameInfoMap; frameInfo;
frameInfo = frameInfo->mNext) {
NS_ASSERTION(!frameSet.Contains(frameInfo->mFrame),
"Frame region deletion was requested but we couldn't delete it");
}
#endif
return NS_OK;
}
nsresult
nsSpaceManager::RemoveRegion(nsIFrame* aFrame)
{
// Get the frame info associated with aFrame
FrameInfo* frameInfo = GetFrameInfoFor(aFrame);
if (nsnull == frameInfo) {
NS_WARNING("no region associated with aFrame");
return NS_ERROR_INVALID_ARG;
}
if (frameInfo->mRect.height > 0) {
NS_ASSERTION(!mBandList.IsEmpty(), "no bands");
BandRect* band = mBandList.Head();
BandRect* prevBand = nsnull;
PRBool prevFoundMatchingRect = PR_FALSE;
// Iterate each band looking for rects tagged with aFrame
while (nsnull != band) {
BandRect* rect = band;
BandRect* prevRect = nsnull;
nscoord topOfBand = band->mTop;
PRBool foundMatchingRect = PR_FALSE;
PRBool prevIsSharedRect = PR_FALSE;
// Iterate each rect in the band
do {
PRBool isSharedRect = PR_FALSE;
if (rect->IsOccupiedBy(aFrame)) {
// Remember that we found a matching rect in this band
foundMatchingRect = PR_TRUE;
if (rect->mNumFrames > 1) {
// The band rect is occupied by more than one frame
rect->RemoveFrame(aFrame);
// Remember that this rect was being shared by more than one frame
// including aFrame
isSharedRect = PR_TRUE;
} else {
// The rect isn't shared so just delete it
BandRect* next = rect->Next();
rect->Remove();
if (rect == band) {
// The rect we're deleting is the start of the band
if (topOfBand == next->mTop) {
band = next;
} else {
band = nsnull;
}
}
delete rect;
rect = next;
// We don't need to try and coalesce adjacent rects in this case
prevRect = nsnull;
prevIsSharedRect = PR_FALSE;
continue;
}
}
// If we found a shared rect occupied by aFrame, then we need to try
// and coalesce adjacent rects
if (prevIsSharedRect || (isSharedRect && (nsnull != prevRect))) {
NS_ASSERTION(nsnull != prevRect, "no previous rect");
if ((prevRect->mRight == rect->mLeft) && (prevRect->HasSameFrameList(rect))) {
// Modify the current rect's left edge, and delete the previous rect
rect->mLeft = prevRect->mLeft;
prevRect->Remove();
if (prevRect == band) {
// the rect we're deleting is the start of the band
band = rect;
}
delete prevRect;
}
}
// Get the next rect in the band
prevRect = rect;
prevIsSharedRect = isSharedRect;
rect = rect->Next();
} while (rect->mTop == topOfBand);
if (nsnull != band) {
// If we found a rect occupied by aFrame in this band or the previous band
// then try to join the two bands
if ((nsnull != prevBand) && (foundMatchingRect || prevFoundMatchingRect)) {
// Try and join this band with the previous band
JoinBands(band, prevBand);
}
}
// Move to the next band
prevFoundMatchingRect = foundMatchingRect;
prevBand = band;
band = (rect == &mBandList) ? nsnull : rect;
}
}
DestroyFrameInfo(frameInfo);
return NS_OK;
}
void
nsSpaceManager::ClearRegions()
{
ClearFrameInfo();
mBandList.Clear();
mLowestTop = NSCOORD_MIN;
mHaveCachedLeftYMost = mHaveCachedRightYMost = PR_TRUE;
mMaximalLeftYMost = mMaximalRightYMost = 0;
}
void
nsSpaceManager::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->mX = mX;
aState->mY = mY;
aState->mLowestTop = mLowestTop;
aState->mHaveCachedLeftYMost = mHaveCachedLeftYMost;
aState->mHaveCachedRightYMost = mHaveCachedRightYMost;
aState->mMaximalLeftYMost = mMaximalLeftYMost;
aState->mMaximalRightYMost = mMaximalRightYMost;
if (mFrameInfoMap) {
aState->mLastFrame = mFrameInfoMap->mFrame;
} else {
aState->mLastFrame = nsnull;
}
}
void
nsSpaceManager::PopState(SavedState* aState)
{
NS_PRECONDITION(aState, "No state to restore?");
// This is a quick and dirty pop implementation, to
// match the current implementation of PushState(). The
// idea here is to remove any frames that have been added
// to the mFrameInfoMap since the last call to PushState().
// Say we don't have cached left- and right-YMost, so that we don't
// try to check for it in RemoveRegion. We'll restore these from
// the state anyway.
mHaveCachedLeftYMost = mHaveCachedRightYMost = PR_FALSE;
// mFrameInfoMap is LIFO so keep removing what it points
// to until we hit mLastFrame.
while (mFrameInfoMap && mFrameInfoMap->mFrame != aState->mLastFrame) {
RemoveRegion(mFrameInfoMap->mFrame);
}
// If we trip this assertion it means that someone added
// PushState()/PopState() calls around code that actually
// removed mLastFrame from mFrameInfoMap, which means our
// state is now out of sync with what we thought it should be.
NS_ASSERTION(((aState->mLastFrame && mFrameInfoMap) ||
(!aState->mLastFrame && !mFrameInfoMap)),
"Unexpected outcome!");
mX = aState->mX;
mY = aState->mY;
mLowestTop = aState->mLowestTop;
mHaveCachedLeftYMost = aState->mHaveCachedLeftYMost;
mHaveCachedRightYMost = aState->mHaveCachedRightYMost;
mMaximalLeftYMost = aState->mMaximalLeftYMost;
mMaximalRightYMost = aState->mMaximalRightYMost;
}
nscoord
nsSpaceManager::GetLowestRegionTop()
{
if (mLowestTop == NSCOORD_MIN)
return mLowestTop;
return mLowestTop - mY;
}
#ifdef DEBUG
void
DebugListSpaceManager(nsSpaceManager *aSpaceManager)
{
aSpaceManager->List(stdout);
}
nsresult
nsSpaceManager::List(FILE* out)
{
nsAutoString tmp;
fprintf(out, "SpaceManager@%p", this);
if (mFrame) {
nsIFrameDebug* frameDebug;
if (NS_SUCCEEDED(mFrame->QueryInterface(NS_GET_IID(nsIFrameDebug), (void**)&frameDebug))) {
frameDebug->GetFrameName(tmp);
fprintf(out, " frame=");
fputs(NS_LossyConvertUTF16toASCII(tmp).get(), out);
fprintf(out, "@%p", mFrame);
}
}
fprintf(out, " xy=%d,%d <\n", mX, mY);
if (mBandList.IsEmpty()) {
fprintf(out, " no bands\n");
}
else {
BandRect* band = mBandList.Head();
do {
fprintf(out, " left=%d top=%d right=%d bottom=%d numFrames=%d",
band->mLeft, band->mTop, band->mRight, band->mBottom,
band->mNumFrames);
if (1 == band->mNumFrames) {
nsIFrameDebug* frameDebug;
if (NS_SUCCEEDED(band->mFrame->QueryInterface(NS_GET_IID(nsIFrameDebug), (void**)&frameDebug))) {
frameDebug->GetFrameName(tmp);
fprintf(out, " frame=");
fputs(NS_LossyConvertUTF16toASCII(tmp).get(), out);
fprintf(out, "@%p", band->mFrame);
}
}
else if (1 < band->mNumFrames) {
fprintf(out, "\n ");
nsVoidArray* a = band->mFrames;
PRInt32 i, n = a->Count();
for (i = 0; i < n; i++) {
nsIFrame* frame = (nsIFrame*) a->ElementAt(i);
if (frame) {
nsIFrameDebug* frameDebug;
if (NS_SUCCEEDED(frame->QueryInterface(NS_GET_IID(nsIFrameDebug), (void**)&frameDebug))) {
frameDebug->GetFrameName(tmp);
fputs(NS_LossyConvertUTF16toASCII(tmp).get(), out);
fprintf(out, "@%p ", frame);
}
}
}
}
fprintf(out, "\n");
band = band->Next();
} while (band != mBandList.Head());
}
fprintf(out, ">\n");
return NS_OK;
}
#endif
nsSpaceManager::FrameInfo*
nsSpaceManager::GetFrameInfoFor(nsIFrame* aFrame)
{
FrameInfo* result = nsnull;
for (result = mFrameInfoMap; result; result = result->mNext) {
if (result->mFrame == aFrame) {
break;
}
}
return result;
}
nsSpaceManager::FrameInfo*
nsSpaceManager::CreateFrameInfo(nsIFrame* aFrame, const nsRect& aRect)
{
FrameInfo* frameInfo = new FrameInfo(aFrame, aRect);
if (frameInfo) {
// Link it into the list
frameInfo->mNext = mFrameInfoMap;
mFrameInfoMap = frameInfo;
// Optimize for the common case case when the frame being added is
// likely to be near the bottom.
nscoord ymost = aRect.YMost();
PRUint8 floatType = aFrame->GetStyleDisplay()->mFloats;
if (mHaveCachedLeftYMost && ymost > mMaximalLeftYMost &&
floatType == NS_STYLE_FLOAT_LEFT) {
mMaximalLeftYMost = ymost;
}
else if (mHaveCachedRightYMost && ymost > mMaximalRightYMost &&
floatType == NS_STYLE_FLOAT_RIGHT) {
mMaximalRightYMost = ymost;
}
}
return frameInfo;
}
void
nsSpaceManager::DestroyFrameInfo(FrameInfo* aFrameInfo)
{
// See if it's at the head of the list
if (mFrameInfoMap == aFrameInfo) {
mFrameInfoMap = aFrameInfo->mNext;
} else {
FrameInfo* prev;
// Find the previous node in the list
for (prev = mFrameInfoMap; prev && (prev->mNext != aFrameInfo); prev = prev->mNext) {
;
}
// Disconnect it from the list
NS_ASSERTION(prev, "element not in list");
if (prev) {
prev->mNext = aFrameInfo->mNext;
}
}
// Optimize for the case when the frame being removed is likely to be near
// the bottom, but do nothing if we have neither cached value -- that case is
// likely to be hit from PopState().
if (mHaveCachedLeftYMost || mHaveCachedRightYMost) {
PRUint8 floatType = aFrameInfo->mFrame->GetStyleDisplay()->mFloats;
if (floatType == NS_STYLE_FLOAT_LEFT) {
mHaveCachedLeftYMost = PR_FALSE;
}
else {
NS_ASSERTION(floatType == NS_STYLE_FLOAT_RIGHT, "Unexpected float type");
mHaveCachedRightYMost = PR_FALSE;
}
}
delete aFrameInfo;
}
nscoord
nsSpaceManager::ClearFloats(nscoord aY, PRUint8 aBreakType)
{
nscoord bottom = aY + mY;
if ((!mHaveCachedLeftYMost && aBreakType != NS_STYLE_CLEAR_RIGHT) ||
(!mHaveCachedRightYMost && aBreakType != NS_STYLE_CLEAR_LEFT)) {
// Recover our maximal YMost values. Might need both if this is a
// NS_STYLE_CLEAR_LEFT_AND_RIGHT
nscoord maximalLeftYMost = mHaveCachedLeftYMost ? mMaximalLeftYMost : 0;
nscoord maximalRightYMost = mHaveCachedRightYMost ? mMaximalRightYMost : 0;
// Optimize for most floats not being near the bottom
for (FrameInfo *frame = mFrameInfoMap; frame; frame = frame->mNext) {
nscoord ymost = frame->mRect.YMost();
if (ymost > maximalLeftYMost) {
if (frame->mFrame->GetStyleDisplay()->mFloats == NS_STYLE_FLOAT_LEFT) {
NS_ASSERTION(!mHaveCachedLeftYMost, "Shouldn't happen");
maximalLeftYMost = ymost;
// No need to compare to the right ymost
continue;
}
}
if (ymost > maximalRightYMost) {
if (frame->mFrame->GetStyleDisplay()->mFloats == NS_STYLE_FLOAT_RIGHT) {
NS_ASSERTION(!mHaveCachedRightYMost, "Shouldn't happen");
maximalRightYMost = ymost;
}
}
}
mMaximalLeftYMost = maximalLeftYMost;
mMaximalRightYMost = maximalRightYMost;
mHaveCachedRightYMost = mHaveCachedLeftYMost = PR_TRUE;
}
switch (aBreakType) {
case NS_STYLE_CLEAR_LEFT_AND_RIGHT:
NS_ASSERTION(mHaveCachedLeftYMost && mHaveCachedRightYMost,
"Need cached values!");
bottom = PR_MAX(bottom, mMaximalLeftYMost);
bottom = PR_MAX(bottom, mMaximalRightYMost);
break;
case NS_STYLE_CLEAR_LEFT:
NS_ASSERTION(mHaveCachedLeftYMost, "Need cached value!");
bottom = PR_MAX(bottom, mMaximalLeftYMost);
break;
case NS_STYLE_CLEAR_RIGHT:
NS_ASSERTION(mHaveCachedRightYMost, "Need cached value!");
bottom = PR_MAX(bottom, mMaximalRightYMost);
break;
default:
// Do nothing
break;
}
bottom -= mY;
return bottom;
}
/////////////////////////////////////////////////////////////////////////////
// FrameInfo
nsSpaceManager::FrameInfo::FrameInfo(nsIFrame* aFrame, const nsRect& aRect)
: mFrame(aFrame), mRect(aRect), mNext(0)
{
MOZ_COUNT_CTOR(nsSpaceManager::FrameInfo);
}
#ifdef NS_BUILD_REFCNT_LOGGING
nsSpaceManager::FrameInfo::~FrameInfo()
{
MOZ_COUNT_DTOR(nsSpaceManager::FrameInfo);
}
#endif
/////////////////////////////////////////////////////////////////////////////
// BandRect
nsSpaceManager::BandRect::BandRect(nscoord aLeft,
nscoord aTop,
nscoord aRight,
nscoord aBottom,
nsIFrame* aFrame)
{
MOZ_COUNT_CTOR(BandRect);
mLeft = aLeft;
mTop = aTop;
mRight = aRight;
mBottom = aBottom;
mFrame = aFrame;
mNumFrames = 1;
}
nsSpaceManager::BandRect::BandRect(nscoord aLeft,
nscoord aTop,
nscoord aRight,
nscoord aBottom,
nsVoidArray* aFrames)
{
MOZ_COUNT_CTOR(BandRect);
mLeft = aLeft;
mTop = aTop;
mRight = aRight;
mBottom = aBottom;
mFrames = new nsVoidArray;
mFrames->operator=(*aFrames);
mNumFrames = mFrames->Count();
}
nsSpaceManager::BandRect::~BandRect()
{
MOZ_COUNT_DTOR(BandRect);
if (mNumFrames > 1) {
delete mFrames;
}
}
nsSpaceManager::BandRect*
nsSpaceManager::BandRect::SplitVertically(nscoord aBottom)
{
NS_PRECONDITION((aBottom > mTop) && (aBottom < mBottom), "bad argument");
// Create a new band rect for the bottom part
BandRect* bottomBandRect;
if (mNumFrames > 1) {
bottomBandRect = new BandRect(mLeft, aBottom, mRight, mBottom, mFrames);
} else {
bottomBandRect = new BandRect(mLeft, aBottom, mRight, mBottom, mFrame);
}
// This band rect becomes the top part, so adjust the bottom edge
mBottom = aBottom;
return bottomBandRect;
}
nsSpaceManager::BandRect*
nsSpaceManager::BandRect::SplitHorizontally(nscoord aRight)
{
NS_PRECONDITION((aRight > mLeft) && (aRight < mRight), "bad argument");
// Create a new band rect for the right part
BandRect* rightBandRect;
if (mNumFrames > 1) {
rightBandRect = new BandRect(aRight, mTop, mRight, mBottom, mFrames);
} else {
rightBandRect = new BandRect(aRight, mTop, mRight, mBottom, mFrame);
}
// This band rect becomes the left part, so adjust the right edge
mRight = aRight;
return rightBandRect;
}
PRBool
nsSpaceManager::BandRect::IsOccupiedBy(const nsIFrame* aFrame) const
{
PRBool result;
if (1 == mNumFrames) {
result = (mFrame == aFrame);
} else {
PRInt32 count = mFrames->Count();
result = PR_FALSE;
for (PRInt32 i = 0; i < count; i++) {
nsIFrame* f = (nsIFrame*)mFrames->ElementAt(i);
if (f == aFrame) {
result = PR_TRUE;
break;
}
}
}
return result;
}
void
nsSpaceManager::BandRect::AddFrame(const nsIFrame* aFrame)
{
if (1 == mNumFrames) {
nsIFrame* f = mFrame;
mFrames = new nsVoidArray;
mFrames->AppendElement(f);
}
mNumFrames++;
mFrames->AppendElement((void*)aFrame);
NS_POSTCONDITION(mFrames->Count() == mNumFrames, "bad frame count");
}
void
nsSpaceManager::BandRect::RemoveFrame(const nsIFrame* aFrame)
{
NS_PRECONDITION(mNumFrames > 1, "only one frame");
mFrames->RemoveElement((void*)aFrame);
mNumFrames--;
if (1 == mNumFrames) {
nsIFrame* f = (nsIFrame*)mFrames->ElementAt(0);
delete mFrames;
mFrame = f;
}
}
PRBool
nsSpaceManager::BandRect::HasSameFrameList(const BandRect* aBandRect) const
{
PRBool result;
// Check whether they're occupied by the same number of frames
if (mNumFrames != aBandRect->mNumFrames) {
result = PR_FALSE;
} else if (1 == mNumFrames) {
result = (mFrame == aBandRect->mFrame);
} else {
result = PR_TRUE;
// For each frame occupying this band rect check whether it also occupies
// aBandRect
PRInt32 count = mFrames->Count();
for (PRInt32 i = 0; i < count; i++) {
nsIFrame* f = (nsIFrame*)mFrames->ElementAt(i);
if (-1 == aBandRect->mFrames->IndexOf(f)) {
result = PR_FALSE;
break;
}
}
}
return result;
}
/**
* Internal helper function that counts the number of rects in this band
* including the current band rect
*/
PRInt32
nsSpaceManager::BandRect::Length() const
{
PRInt32 len = 1;
BandRect* bandRect = Next();
// Because there's a header cell we know we'll either find the next band
// (which has a different y-offset) or the header cell which has an invalid
// y-offset
while (bandRect->mTop == mTop) {
len++;
bandRect = bandRect->Next();
}
return len;
}
//----------------------------------------------------------------------
nsAutoSpaceManager::~nsAutoSpaceManager()
{
// Restore the old space manager in the reflow state if necessary.
if (mNew) {
#ifdef NOISY_SPACEMANAGER
printf("restoring old space manager %p\n", mOld);
#endif
mReflowState.mSpaceManager = mOld;
#ifdef NOISY_SPACEMANAGER
if (mOld) {
NS_STATIC_CAST(nsFrame *, mReflowState.frame)->ListTag(stdout);
printf(": space-manager %p after reflow\n", mOld);
mOld->List(stdout);
}
#endif
#ifdef DEBUG
if (mOwns)
#endif
delete mNew;
}
}
nsresult
nsAutoSpaceManager::CreateSpaceManagerFor(nsPresContext *aPresContext, nsIFrame *aFrame)
{
// Create a new space manager and install it in the reflow
// state. `Remember' the old space manager so we can restore it
// later.
mNew = new nsSpaceManager(aPresContext->PresShell(), aFrame);
if (! mNew)
return NS_ERROR_OUT_OF_MEMORY;
#ifdef NOISY_SPACEMANAGER
printf("constructed new space manager %p (replacing %p)\n",
mNew, mReflowState.mSpaceManager);
#endif
// Set the space manager in the existing reflow state
mOld = mReflowState.mSpaceManager;
mReflowState.mSpaceManager = mNew;
return NS_OK;
}
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