summaryrefslogtreecommitdiffstats
path: root/layout/generic/nsFloatManager.cpp
blob: 2c0ff1f38fcbff91e90c4dbe9edbc77b09690b2e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
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;
}