1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
3 /* This Source Code Form is subject to the terms of the Mozilla Public
4 * License, v. 2.0. If a copy of the MPL was not distributed with this
5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
6
7 /* constants for what needs to be recomputed in response to style changes */
8
9 #ifndef nsChangeHint_h___
10 #define nsChangeHint_h___
11
12 #include "mozilla/Types.h"
13 #include "nsDebug.h"
14 #include "nsTArray.h"
15
16 struct nsCSSSelector;
17
18 // Defines for various style related constants
19
20 enum nsChangeHint : uint32_t {
21 nsChangeHint_Empty = 0,
22
23 // change was visual only (e.g., COLOR=)
24 // Invalidates all descendant frames (including following
25 // placeholders to out-of-flow frames).
26 nsChangeHint_RepaintFrame = 1 << 0,
27
28 // For reflow, we want flags to give us arbitrary FrameNeedsReflow behavior.
29 // just do a FrameNeedsReflow.
30 nsChangeHint_NeedReflow = 1 << 1,
31
32 // Invalidate intrinsic widths on the frame's ancestors. Must not be set
33 // without setting nsChangeHint_NeedReflow.
34 nsChangeHint_ClearAncestorIntrinsics = 1 << 2,
35
36 // Invalidate intrinsic widths on the frame's descendants. Must not be set
37 // without also setting nsChangeHint_ClearAncestorIntrinsics,
38 // nsChangeHint_NeedDirtyReflow and nsChangeHint_NeedReflow.
39 nsChangeHint_ClearDescendantIntrinsics = 1 << 3,
40
41 // Force unconditional reflow of all descendants. Must not be set without
42 // setting nsChangeHint_NeedReflow, but can be set regardless of whether the
43 // Clear*Intrinsics flags are set.
44 nsChangeHint_NeedDirtyReflow = 1 << 4,
45
46 // change requires view to be updated, if there is one (e.g., clip:).
47 // Updates all descendants (including following placeholders to out-of-flows).
48 nsChangeHint_SyncFrameView = 1 << 5,
49
50 // The currently shown mouse cursor needs to be updated
51 nsChangeHint_UpdateCursor = 1 << 6,
52
53 /**
54 * Used when the computed value (a URI) of one or more of an element's
55 * filter/mask/clip/etc CSS properties changes, causing the element's frame
56 * to start/stop referencing (or reference different) SVG resource elements.
57 * (_Not_ used to handle changes to referenced resource elements.) Using this
58 * hint results in SVGObserverUtils::UpdateEffects being called on the
59 * element's frame.
60 */
61 nsChangeHint_UpdateEffects = 1 << 7,
62
63 /**
64 * Visual change only, but the change can be handled entirely by
65 * updating the layer(s) for the frame.
66 * Updates all descendants (including following placeholders to out-of-flows).
67 */
68 nsChangeHint_UpdateOpacityLayer = 1 << 8,
69 /**
70 * Updates all descendants. Any placeholder descendants' out-of-flows
71 * are also descendants of the transformed frame, so they're updated.
72 */
73 nsChangeHint_UpdateTransformLayer = 1 << 9,
74
75 /**
76 * Change requires frame change (e.g., display:).
77 * Reconstructs all frame descendants, including following placeholders
78 * to out-of-flows.
79 *
80 * Note that this subsumes all the other change hints. (see
81 * RestyleManager::ProcessRestyledFrames for details).
82 */
83 nsChangeHint_ReconstructFrame = 1 << 10,
84
85 /**
86 * The frame's overflow area has changed. Does not update any descendant
87 * frames.
88 */
89 nsChangeHint_UpdateOverflow = 1 << 11,
90
91 /**
92 * The overflow area of the frame and all of its descendants has changed. This
93 * can happen through a text-decoration change.
94 */
95 nsChangeHint_UpdateSubtreeOverflow = 1 << 12,
96
97 /**
98 * The frame's overflow area has changed, through a change in its transform.
99 * In other words, the frame's pre-transform overflow is unchanged, but
100 * its post-transform overflow has changed, and thus its effect on its
101 * parent's overflow has changed. If the pre-transform overflow has
102 * changed, see nsChangeHint_UpdateOverflow.
103 * Does not update any descendant frames.
104 */
105 nsChangeHint_UpdatePostTransformOverflow = 1 << 13,
106
107 /**
108 * This frame's effect on its parent's overflow area has changed.
109 * (But neither its pre-transform nor post-transform overflow have
110 * changed; if those are the case, see
111 * nsChangeHint_UpdatePostTransformOverflow.)
112 */
113 nsChangeHint_UpdateParentOverflow = 1 << 14,
114
115 /**
116 * The children-only transform of an SVG frame changed, requiring the
117 * overflow rects of the frame's immediate children to be updated.
118 */
119 nsChangeHint_ChildrenOnlyTransform = 1 << 15,
120
121 /**
122 * The frame's offsets have changed, while its dimensions might have
123 * changed as well. This hint is used for positioned frames if their
124 * offset changes. If we decide that the dimensions are likely to
125 * change, this will trigger a reflow.
126 *
127 * Note that this should probably be used in combination with
128 * nsChangeHint_UpdateOverflow in order to get the overflow areas of
129 * the ancestors updated as well.
130 */
131 nsChangeHint_RecomputePosition = 1 << 16,
132
133 /**
134 * Behaves like ReconstructFrame, but only if the frame has descendants
135 * that are absolutely or fixed position. Use this hint when a style change
136 * has changed whether the frame is a container for fixed-pos or abs-pos
137 * elements, but reframing is otherwise not needed.
138 *
139 * Note that nsStyleContext::CalcStyleDifference adjusts results
140 * returned by style struct CalcDifference methods to return this hint
141 * only if there was a change to whether the element's overall style
142 * indicates that it establishes a containing block.
143 */
144 nsChangeHint_UpdateContainingBlock = 1 << 17,
145
146 /**
147 * This change hint has *no* change handling behavior. However, it
148 * exists to be a non-inherited hint, because when the border-style
149 * changes, and it's inherited by a child, that might require a reflow
150 * due to the border-width change on the child.
151 */
152 nsChangeHint_BorderStyleNoneChange = 1 << 18,
153
154 /**
155 * SVG textPath needs to be recomputed because the path has changed.
156 * This means that the glyph positions of the text need to be recomputed.
157 */
158 nsChangeHint_UpdateTextPath = 1 << 19,
159
160 /**
161 * This will schedule an invalidating paint. This is useful if something
162 * has changed which will be invalidated by DLBI.
163 */
164 nsChangeHint_SchedulePaint = 1 << 20,
165
166 /**
167 * A hint reflecting that style data changed with no change handling
168 * behavior. We need to return this, rather than nsChangeHint(0),
169 * so that certain optimizations that manipulate the style context tree are
170 * correct.
171 *
172 * nsChangeHint_NeutralChange must be returned by CalcDifference on a given
173 * style struct if the data in the style structs are meaningfully different
174 * and if no other change hints are returned. If any other change hints are
175 * set, then nsChangeHint_NeutralChange need not also be included, but it is
176 * safe to do so. (An example of style structs having non-meaningfully
177 * different data would be cached information that would be re-calculated
178 * to the same values, such as nsStyleBorder::mSubImages.)
179 */
180 nsChangeHint_NeutralChange = 1 << 21,
181
182 /**
183 * This will cause rendering observers to be invalidated.
184 */
185 nsChangeHint_InvalidateRenderingObservers = 1 << 22,
186
187 /**
188 * Indicates that the reflow changes the size or position of the
189 * element, and thus the reflow must start from at least the frame's
190 * parent. Must be not be set without also setting nsChangeHint_NeedReflow
191 * and nsChangeHint_ClearAncestorIntrinsics.
192 */
193 nsChangeHint_ReflowChangesSizeOrPosition = 1 << 23,
194
195 /**
196 * Indicates that the style changes the computed BSize --- e.g. 'height'.
197 * Must not be set without also setting nsChangeHint_NeedReflow.
198 */
199 nsChangeHint_UpdateComputedBSize = 1 << 24,
200
201 /**
202 * Indicates that the 'opacity' property changed between 1 and non-1.
203 *
204 * Used as extra data for handling UpdateOpacityLayer hints.
205 *
206 * Note that we do not send this hint if the non-1 value was 0.99 or
207 * greater, since in that case we send a RepaintFrame hint instead.
208 */
209 nsChangeHint_UpdateUsesOpacity = 1 << 25,
210
211 /**
212 * Indicates that the 'background-position' property changed.
213 * Regular frames can invalidate these changes using DLBI, but
214 * for some frame types we need to repaint the whole frame because
215 * the frame does not build individual background image display items
216 * for each background layer.
217 */
218 nsChangeHint_UpdateBackgroundPosition = 1 << 26,
219
220 /**
221 * Indicates that a frame has changed to or from having the CSS
222 * transform property set.
223 */
224 nsChangeHint_AddOrRemoveTransform = 1 << 27,
225
226 /**
227 * Indicates that the overflow-x and/or overflow-y property changed.
228 *
229 * In most cases, this is equivalent to nsChangeHint_ReconstructFrame. But
230 * in some special cases where the change is really targeting the viewport's
231 * scrollframe, this is instead equivalent to nsChangeHint_AllReflowHints
232 * (because the viewport always has an associated scrollframe).
233 */
234 nsChangeHint_CSSOverflowChange = 1 << 28,
235
236 /**
237 * Indicates that nsIFrame::UpdateWidgetProperties needs to be called.
238 * This is used for -moz-window-* properties.
239 */
240 nsChangeHint_UpdateWidgetProperties = 1 << 29,
241
242 /**
243 * Indicates that there has been a colspan or rowspan attribute change
244 * on the cells of a table.
245 */
246 nsChangeHint_UpdateTableCellSpans = 1 << 30,
247
248 /**
249 * Indicates that the visiblity property changed.
250 * This change hint is used for skip restyling for animations on
251 * visibility:hidden elements in the case where the elements have no visible
252 * descendants.
253 */
254 nsChangeHint_VisibilityChange = 1u << 31,
255
256 // IMPORTANT NOTE: When adding a new hint, you will need to add it to
257 // one of:
258 //
259 // * nsChangeHint_Hints_NeverHandledForDescendants
260 // * nsChangeHint_Hints_AlwaysHandledForDescendants
261 // * nsChangeHint_Hints_SometimesHandledForDescendants
262 //
263 // and you also may need to handle it in NS_HintsNotHandledForDescendantsIn.
264 //
265 // Please also add it to RestyleManager::ChangeHintToString and
266 // modify nsChangeHint_AllHints below accordingly.
267
268 /**
269 * Dummy hint value for all hints. It exists for compile time check.
270 */
271 nsChangeHint_AllHints = uint32_t((1ull << 32) - 1),
272 };
273
274 // Redefine these operators to return nothing. This will catch any use
275 // of these operators on hints. We should not be using these operators
276 // on nsChangeHints
277 inline void operator<(nsChangeHint s1, nsChangeHint s2) {}
278 inline void operator>(nsChangeHint s1, nsChangeHint s2) {}
279 inline void operator!=(nsChangeHint s1, nsChangeHint s2) {}
280 inline void operator==(nsChangeHint s1, nsChangeHint s2) {}
281 inline void operator<=(nsChangeHint s1, nsChangeHint s2) {}
282 inline void operator>=(nsChangeHint s1, nsChangeHint s2) {}
283
284 // Operators on nsChangeHints
285
286 // Returns true iff the second hint contains all the hints of the first hint
NS_IsHintSubset(nsChangeHint aSubset,nsChangeHint aSuperSet)287 inline bool NS_IsHintSubset(nsChangeHint aSubset, nsChangeHint aSuperSet) {
288 return (aSubset & aSuperSet) == aSubset;
289 }
290
291 // The functions below need an integral type to cast to to avoid
292 // infinite recursion.
293 typedef decltype(nsChangeHint(0) + nsChangeHint(0)) nsChangeHint_size_t;
294
295 inline nsChangeHint constexpr operator|(nsChangeHint aLeft,
296 nsChangeHint aRight) {
297 return nsChangeHint(nsChangeHint_size_t(aLeft) | nsChangeHint_size_t(aRight));
298 }
299
300 inline nsChangeHint constexpr operator&(nsChangeHint aLeft,
301 nsChangeHint aRight) {
302 return nsChangeHint(nsChangeHint_size_t(aLeft) & nsChangeHint_size_t(aRight));
303 }
304
305 inline nsChangeHint& operator|=(nsChangeHint& aLeft, nsChangeHint aRight) {
306 return aLeft = aLeft | aRight;
307 }
308
309 inline nsChangeHint& operator&=(nsChangeHint& aLeft, nsChangeHint aRight) {
310 return aLeft = aLeft & aRight;
311 }
312
313 inline nsChangeHint constexpr operator~(nsChangeHint aArg) {
314 return nsChangeHint(~nsChangeHint_size_t(aArg));
315 }
316
317 inline nsChangeHint constexpr operator^(nsChangeHint aLeft,
318 nsChangeHint aRight) {
319 return nsChangeHint(nsChangeHint_size_t(aLeft) ^ nsChangeHint_size_t(aRight));
320 }
321
322 inline nsChangeHint operator^=(nsChangeHint& aLeft, nsChangeHint aRight) {
323 return aLeft = aLeft ^ aRight;
324 }
325
326 /**
327 * We have an optimization when processing change hints which prevents
328 * us from visiting the descendants of a node when a hint on that node
329 * is being processed. This optimization does not apply in some of the
330 * cases where applying a hint to an element does not necessarily result
331 * in the same hint being handled on the descendants.
332 */
333
334 // The change hints that are always handled for descendants.
335 #define nsChangeHint_Hints_AlwaysHandledForDescendants \
336 (nsChangeHint_ClearDescendantIntrinsics | nsChangeHint_NeedDirtyReflow | \
337 nsChangeHint_NeutralChange | nsChangeHint_ReconstructFrame | \
338 nsChangeHint_RepaintFrame | nsChangeHint_SchedulePaint | \
339 nsChangeHint_SyncFrameView | nsChangeHint_UpdateCursor | \
340 nsChangeHint_UpdateSubtreeOverflow | nsChangeHint_UpdateTextPath | \
341 nsChangeHint_VisibilityChange)
342
343 // The change hints that are never handled for descendants.
344 #define nsChangeHint_Hints_NeverHandledForDescendants \
345 (nsChangeHint_BorderStyleNoneChange | nsChangeHint_ChildrenOnlyTransform | \
346 nsChangeHint_CSSOverflowChange | \
347 nsChangeHint_InvalidateRenderingObservers | \
348 nsChangeHint_RecomputePosition | nsChangeHint_UpdateBackgroundPosition | \
349 nsChangeHint_UpdateComputedBSize | nsChangeHint_UpdateContainingBlock | \
350 nsChangeHint_UpdateEffects | nsChangeHint_UpdateOpacityLayer | \
351 nsChangeHint_UpdateOverflow | nsChangeHint_UpdateParentOverflow | \
352 nsChangeHint_UpdatePostTransformOverflow | \
353 nsChangeHint_UpdateTableCellSpans | nsChangeHint_UpdateTransformLayer | \
354 nsChangeHint_UpdateUsesOpacity | nsChangeHint_AddOrRemoveTransform | \
355 nsChangeHint_UpdateWidgetProperties)
356
357 // The change hints that are sometimes considered to be handled for descendants.
358 #define nsChangeHint_Hints_SometimesHandledForDescendants \
359 (nsChangeHint_ClearAncestorIntrinsics | nsChangeHint_NeedReflow | \
360 nsChangeHint_ReflowChangesSizeOrPosition)
361
362 static_assert(!(nsChangeHint_Hints_AlwaysHandledForDescendants &
363 nsChangeHint_Hints_NeverHandledForDescendants) &&
364 !(nsChangeHint_Hints_AlwaysHandledForDescendants &
365 nsChangeHint_Hints_SometimesHandledForDescendants) &&
366 !(nsChangeHint_Hints_NeverHandledForDescendants &
367 nsChangeHint_Hints_SometimesHandledForDescendants) &&
368 !(nsChangeHint_AllHints ^
369 nsChangeHint_Hints_AlwaysHandledForDescendants ^
370 nsChangeHint_Hints_NeverHandledForDescendants ^
371 nsChangeHint_Hints_SometimesHandledForDescendants),
372 "change hints must be present in exactly one of "
373 "nsChangeHint_Hints_{Always,Never,Sometimes}"
374 "HandledForDescendants");
375
376 // The most hints that NS_HintsNotHandledForDescendantsIn could possibly return:
377 #define nsChangeHint_Hints_NotHandledForDescendants \
378 (nsChangeHint_Hints_NeverHandledForDescendants | \
379 nsChangeHint_Hints_SometimesHandledForDescendants)
380
381 // Redefine the old NS_STYLE_HINT constants in terms of the new hint structure
382 #define NS_STYLE_HINT_VISUAL \
383 nsChangeHint(nsChangeHint_RepaintFrame | nsChangeHint_SyncFrameView | \
384 nsChangeHint_SchedulePaint)
385 #define nsChangeHint_AllReflowHints \
386 nsChangeHint( \
387 nsChangeHint_NeedReflow | nsChangeHint_ReflowChangesSizeOrPosition | \
388 nsChangeHint_ClearAncestorIntrinsics | \
389 nsChangeHint_ClearDescendantIntrinsics | nsChangeHint_NeedDirtyReflow)
390
391 // Below are the change hints that we send for ISize & BSize changes.
392 // Each is similar to nsChangeHint_AllReflowHints with a few changes.
393
394 // * For an ISize change, we send nsChangeHint_AllReflowHints, with two bits
395 // excluded: nsChangeHint_ClearDescendantIntrinsics (because an ancestor's
396 // inline-size change can't affect descendant intrinsic sizes), and
397 // nsChangeHint_NeedDirtyReflow (because ISize changes don't need to *force*
398 // all descendants to reflow).
399 #define nsChangeHint_ReflowHintsForISizeChange \
400 nsChangeHint(nsChangeHint_AllReflowHints & \
401 ~(nsChangeHint_ClearDescendantIntrinsics | \
402 nsChangeHint_NeedDirtyReflow))
403
404 // * For a BSize change, we send almost the same hints as for ISize changes,
405 // with one extra: nsChangeHint_UpdateComputedBSize. We need this hint because
406 // BSize changes CAN affect descendant intrinsic sizes, due to replaced
407 // elements with percentage BSizes in descendants which also have percentage
408 // BSizes. nsChangeHint_UpdateComputedBSize clears intrinsic sizes for frames
409 // that have such replaced elements. (We could instead send
410 // nsChangeHint_ClearDescendantIntrinsics, but that's broader than we need.)
411 //
412 // NOTE: You might think that BSize changes could exclude
413 // nsChangeHint_ClearAncestorIntrinsics (which is inline-axis specific), but we
414 // do need to send it, to clear cached results from CSS Flex measuring reflows.
415 #define nsChangeHint_ReflowHintsForBSizeChange \
416 nsChangeHint( \
417 (nsChangeHint_AllReflowHints | nsChangeHint_UpdateComputedBSize) & \
418 ~(nsChangeHint_ClearDescendantIntrinsics | \
419 nsChangeHint_NeedDirtyReflow))
420
421 // * For changes to the float area of an already-floated element, we need all
422 // reflow hints, but not the ones that apply to descendants.
423 // Our descendants aren't impacted when our float area only changes
424 // placement but not size/shape. (e.g. if we change which side we float to).
425 // But our ancestors/siblings are potentially impacted, so we need to send
426 // the non-descendant reflow hints.
427 #define nsChangeHint_ReflowHintsForFloatAreaChange \
428 nsChangeHint(nsChangeHint_AllReflowHints & \
429 ~(nsChangeHint_ClearDescendantIntrinsics | \
430 nsChangeHint_NeedDirtyReflow))
431
432 #define NS_STYLE_HINT_REFLOW \
433 nsChangeHint(NS_STYLE_HINT_VISUAL | nsChangeHint_AllReflowHints)
434
435 #define nsChangeHint_Hints_CanIgnoreIfNotVisible \
436 nsChangeHint(NS_STYLE_HINT_VISUAL | nsChangeHint_NeutralChange | \
437 nsChangeHint_UpdateOpacityLayer | \
438 nsChangeHint_AddOrRemoveTransform | \
439 nsChangeHint_UpdatePostTransformOverflow | \
440 nsChangeHint_UpdateTransformLayer | \
441 nsChangeHint_UpdateUsesOpacity | nsChangeHint_VisibilityChange)
442
443 // NB: Once we drop support for the old style system, this logic should be
444 // inlined in the Servo style system to eliminate the FFI call.
NS_HintsNotHandledForDescendantsIn(nsChangeHint aChangeHint)445 inline nsChangeHint NS_HintsNotHandledForDescendantsIn(
446 nsChangeHint aChangeHint) {
447 nsChangeHint result =
448 aChangeHint & nsChangeHint_Hints_NeverHandledForDescendants;
449
450 if (!NS_IsHintSubset(nsChangeHint_NeedDirtyReflow, aChangeHint)) {
451 if (NS_IsHintSubset(nsChangeHint_NeedReflow, aChangeHint)) {
452 // If NeedDirtyReflow is *not* set, then NeedReflow is a
453 // non-inherited hint.
454 result |= nsChangeHint_NeedReflow;
455 }
456
457 if (NS_IsHintSubset(nsChangeHint_ReflowChangesSizeOrPosition,
458 aChangeHint)) {
459 // If NeedDirtyReflow is *not* set, then ReflowChangesSizeOrPosition is a
460 // non-inherited hint.
461 result |= nsChangeHint_ReflowChangesSizeOrPosition;
462 }
463 }
464
465 if (!NS_IsHintSubset(nsChangeHint_ClearDescendantIntrinsics, aChangeHint) &&
466 NS_IsHintSubset(nsChangeHint_ClearAncestorIntrinsics, aChangeHint)) {
467 // If ClearDescendantIntrinsics is *not* set, then
468 // ClearAncestorIntrinsics is a non-inherited hint.
469 result |= nsChangeHint_ClearAncestorIntrinsics;
470 }
471
472 MOZ_ASSERT(
473 NS_IsHintSubset(result, nsChangeHint_Hints_NotHandledForDescendants),
474 "something is inconsistent");
475
476 return result;
477 }
478
NS_HintsHandledForDescendantsIn(nsChangeHint aChangeHint)479 inline nsChangeHint NS_HintsHandledForDescendantsIn(nsChangeHint aChangeHint) {
480 return aChangeHint & ~NS_HintsNotHandledForDescendantsIn(aChangeHint);
481 }
482
483 // Returns the change hints in aOurChange that are not subsumed by those
484 // in aHintsHandled (which are hints that have been handled by an ancestor).
NS_RemoveSubsumedHints(nsChangeHint aOurChange,nsChangeHint aHintsHandled)485 inline nsChangeHint NS_RemoveSubsumedHints(nsChangeHint aOurChange,
486 nsChangeHint aHintsHandled) {
487 nsChangeHint result =
488 aOurChange & ~NS_HintsHandledForDescendantsIn(aHintsHandled);
489
490 if (result &
491 (nsChangeHint_ClearAncestorIntrinsics |
492 nsChangeHint_ClearDescendantIntrinsics | nsChangeHint_NeedDirtyReflow |
493 nsChangeHint_ReflowChangesSizeOrPosition |
494 nsChangeHint_UpdateComputedBSize)) {
495 result |= nsChangeHint_NeedReflow;
496 }
497
498 if (result & (nsChangeHint_ClearDescendantIntrinsics)) {
499 MOZ_ASSERT(result & nsChangeHint_ClearAncestorIntrinsics);
500 result |= // nsChangeHint_ClearAncestorIntrinsics |
501 nsChangeHint_NeedDirtyReflow;
502 }
503
504 return result;
505 }
506
507 /**
508 * |nsRestyleHint| is a bitfield for the result of
509 * |HasStateDependentStyle| and |HasAttributeDependentStyle|. When no
510 * restyling is necessary, use |nsRestyleHint(0)|.
511 *
512 * Without eRestyle_Force or eRestyle_ForceDescendants, the restyling process
513 * can stop processing at a frame when it detects no style changes and it is
514 * known that the styles of the subtree beneath it will not change, leaving
515 * the old style context on the frame. eRestyle_Force can be used to skip this
516 * optimization on a frame, and to force its new style context to be used.
517 *
518 * Similarly, eRestyle_ForceDescendants will cause the frame and all of its
519 * descendants to be traversed and for the new style contexts that are created
520 * to be set on the frames.
521 *
522 * NOTE: When adding new restyle hints, please also add them to
523 * RestyleManager::RestyleHintToString.
524 */
525 enum nsRestyleHint : uint32_t {
526 // Rerun selector matching on the element. If a new style context
527 // results, update the style contexts of descendants. (Irrelevant if
528 // eRestyle_Subtree is also set, since that implies a superset of the
529 // work.)
530 eRestyle_Self = 1 << 0,
531
532 // Rerun selector matching on descendants of the element that match
533 // a given selector.
534 eRestyle_SomeDescendants = 1 << 1,
535
536 // Rerun selector matching on the element and all of its descendants.
537 // (Implies eRestyle_ForceDescendants, which ensures that we continue
538 // the restyling process for all descendants, but doesn't cause
539 // selector matching.)
540 eRestyle_Subtree = 1 << 2,
541
542 // Rerun selector matching on all later siblings of the element and
543 // all of their descendants.
544 eRestyle_LaterSiblings = 1 << 3,
545
546 // Replace the style data coming from CSS transitions without updating
547 // any other style data. If a new style context results, update style
548 // contexts on the descendants. (Irrelevant if eRestyle_Self or
549 // eRestyle_Subtree is also set, since those imply a superset of the
550 // work.)
551 eRestyle_CSSTransitions = 1 << 4,
552
553 // Replace the style data coming from CSS animations without updating
554 // any other style data. If a new style context results, update style
555 // contexts on the descendants. (Irrelevant if eRestyle_Self or
556 // eRestyle_Subtree is also set, since those imply a superset of the
557 // work.)
558 eRestyle_CSSAnimations = 1 << 5,
559
560 // Replace the style data coming from inline style without updating
561 // any other style data. If a new style context results, update style
562 // contexts on the descendants. (Irrelevant if eRestyle_Self or
563 // eRestyle_Subtree is also set, since those imply a superset of the
564 // work.) Supported only for element style contexts and not for
565 // pseudo-elements or anonymous boxes, on which it converts to
566 // eRestyle_Self.
567 // If the change is for the advance of a declarative animation, use
568 // the value below instead.
569 eRestyle_StyleAttribute = 1 << 6,
570
571 // Same as eRestyle_StyleAttribute, but for when the change results
572 // from the advance of a declarative animation.
573 eRestyle_StyleAttribute_Animations = 1 << 7,
574
575 // Continue the restyling process to the current frame's children even
576 // if this frame's restyling resulted in no style changes.
577 eRestyle_Force = 1 << 8,
578
579 // Continue the restyling process to all of the current frame's
580 // descendants, even if any frame's restyling resulted in no style
581 // changes. (Implies eRestyle_Force.) Note that this is weaker than
582 // eRestyle_Subtree, which makes us rerun selector matching on all
583 // descendants rather than just continuing the restyling process.
584 eRestyle_ForceDescendants = 1 << 9,
585
586 // Useful unions:
587 eRestyle_AllHintsWithAnimations = eRestyle_CSSTransitions |
588 eRestyle_CSSAnimations |
589 eRestyle_StyleAttribute_Animations,
590 };
591
592 // The functions below need an integral type to cast to to avoid
593 // infinite recursion.
594 typedef decltype(nsRestyleHint(0) + nsRestyleHint(0)) nsRestyleHint_size_t;
595
596 inline constexpr nsRestyleHint operator|(nsRestyleHint aLeft,
597 nsRestyleHint aRight) {
598 return nsRestyleHint(nsRestyleHint_size_t(aLeft) |
599 nsRestyleHint_size_t(aRight));
600 }
601
602 inline constexpr nsRestyleHint operator&(nsRestyleHint aLeft,
603 nsRestyleHint aRight) {
604 return nsRestyleHint(nsRestyleHint_size_t(aLeft) &
605 nsRestyleHint_size_t(aRight));
606 }
607
608 inline nsRestyleHint& operator|=(nsRestyleHint& aLeft, nsRestyleHint aRight) {
609 return aLeft = aLeft | aRight;
610 }
611
612 inline nsRestyleHint& operator&=(nsRestyleHint& aLeft, nsRestyleHint aRight) {
613 return aLeft = aLeft & aRight;
614 }
615
616 inline constexpr nsRestyleHint operator~(nsRestyleHint aArg) {
617 return nsRestyleHint(~nsRestyleHint_size_t(aArg));
618 }
619
620 inline constexpr nsRestyleHint operator^(nsRestyleHint aLeft,
621 nsRestyleHint aRight) {
622 return nsRestyleHint(nsRestyleHint_size_t(aLeft) ^
623 nsRestyleHint_size_t(aRight));
624 }
625
626 inline nsRestyleHint operator^=(nsRestyleHint& aLeft, nsRestyleHint aRight) {
627 return aLeft = aLeft ^ aRight;
628 }
629
630 namespace mozilla {
631
632 /**
633 * Additional data used in conjunction with an nsRestyleHint to control the
634 * restyle process.
635 */
636 struct RestyleHintData {
637 // When eRestyle_SomeDescendants is used, this array contains the selectors
638 // that identify which descendants will be restyled.
639 nsTArray<nsCSSSelector*> mSelectorsForDescendants;
640 };
641
642 } // namespace mozilla
643
644 #endif /* nsChangeHint_h___ */
645