1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/layout/base/RestyleManager.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,405 @@
1.4 +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
1.5 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.6 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.7 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.8 +
1.9 +/**
1.10 + * Code responsible for managing style changes: tracking what style
1.11 + * changes need to happen, scheduling them, and doing them.
1.12 + */
1.13 +
1.14 +#ifndef mozilla_RestyleManager_h
1.15 +#define mozilla_RestyleManager_h
1.16 +
1.17 +#include "nsISupportsImpl.h"
1.18 +#include "nsChangeHint.h"
1.19 +#include "RestyleTracker.h"
1.20 +#include "nsPresContext.h"
1.21 +
1.22 +class nsRefreshDriver;
1.23 +class nsIFrame;
1.24 +struct TreeMatchContext;
1.25 +
1.26 +namespace mozilla {
1.27 + class EventStates;
1.28 +
1.29 +namespace dom {
1.30 + class Element;
1.31 +} // namespace dom
1.32 +
1.33 +class RestyleManager MOZ_FINAL {
1.34 +public:
1.35 + friend class ::nsRefreshDriver;
1.36 + friend class RestyleTracker;
1.37 +
1.38 + typedef mozilla::dom::Element Element;
1.39 +
1.40 + RestyleManager(nsPresContext* aPresContext);
1.41 +
1.42 +private:
1.43 + // Private destructor, to discourage deletion outside of Release():
1.44 + ~RestyleManager()
1.45 + {
1.46 + }
1.47 +
1.48 +public:
1.49 + NS_INLINE_DECL_REFCOUNTING(mozilla::RestyleManager)
1.50 +
1.51 + void Disconnect() {
1.52 + mPresContext = nullptr;
1.53 + }
1.54 +
1.55 + nsPresContext* PresContext() const {
1.56 + MOZ_ASSERT(mPresContext);
1.57 + return mPresContext;
1.58 + }
1.59 +
1.60 + nsCSSFrameConstructor* FrameConstructor() const
1.61 + { return PresContext()->FrameConstructor(); }
1.62 +
1.63 + // Should be called when a frame is going to be destroyed and
1.64 + // WillDestroyFrameTree hasn't been called yet.
1.65 + void NotifyDestroyingFrame(nsIFrame* aFrame);
1.66 +
1.67 + // Forwarded nsIDocumentObserver method, to handle restyling (and
1.68 + // passing the notification to the frame).
1.69 + nsresult ContentStateChanged(nsIContent* aContent,
1.70 + EventStates aStateMask);
1.71 +
1.72 + // Forwarded nsIMutationObserver method, to handle restyling.
1.73 + void AttributeWillChange(Element* aElement,
1.74 + int32_t aNameSpaceID,
1.75 + nsIAtom* aAttribute,
1.76 + int32_t aModType);
1.77 + // Forwarded nsIMutationObserver method, to handle restyling (and
1.78 + // passing the notification to the frame).
1.79 + void AttributeChanged(Element* aElement,
1.80 + int32_t aNameSpaceID,
1.81 + nsIAtom* aAttribute,
1.82 + int32_t aModType);
1.83 +
1.84 + // Get an integer that increments every time there is a style change
1.85 + // as a result of a change to the :hover content state.
1.86 + uint32_t GetHoverGeneration() const { return mHoverGeneration; }
1.87 +
1.88 + // Get a counter that increments on every style change, that we use to
1.89 + // track whether off-main-thread animations are up-to-date.
1.90 + uint64_t GetAnimationGeneration() const { return mAnimationGeneration; }
1.91 +
1.92 + /**
1.93 + * Reparent the style contexts of this frame subtree. The parent frame of
1.94 + * aFrame must be changed to the new parent before this function is called;
1.95 + * the new parent style context will be automatically computed based on the
1.96 + * new position in the frame tree.
1.97 + *
1.98 + * @param aFrame the root of the subtree to reparent. Must not be null.
1.99 + */
1.100 + NS_HIDDEN_(nsresult) ReparentStyleContext(nsIFrame* aFrame);
1.101 +
1.102 + /**
1.103 + * Re-resolve the style contexts for a frame tree, building
1.104 + * aChangeList based on the resulting style changes, plus aMinChange
1.105 + * applied to aFrame.
1.106 + */
1.107 + NS_HIDDEN_(void)
1.108 + ComputeStyleChangeFor(nsIFrame* aFrame,
1.109 + nsStyleChangeList* aChangeList,
1.110 + nsChangeHint aMinChange,
1.111 + RestyleTracker& aRestyleTracker,
1.112 + bool aRestyleDescendants);
1.113 +
1.114 +#ifdef DEBUG
1.115 + /**
1.116 + * DEBUG ONLY method to verify integrity of style tree versus frame tree
1.117 + */
1.118 + NS_HIDDEN_(void) DebugVerifyStyleTree(nsIFrame* aFrame);
1.119 +#endif
1.120 +
1.121 + // Note: It's the caller's responsibility to make sure to wrap a
1.122 + // ProcessRestyledFrames call in a view update batch and a script blocker.
1.123 + // This function does not call ProcessAttachedQueue() on the binding manager.
1.124 + // If the caller wants that to happen synchronously, it needs to handle that
1.125 + // itself.
1.126 + nsresult ProcessRestyledFrames(nsStyleChangeList& aRestyleArray);
1.127 +
1.128 +private:
1.129 + void RestyleForEmptyChange(Element* aContainer);
1.130 +
1.131 +public:
1.132 + // Restyling for a ContentInserted (notification after insertion) or
1.133 + // for a CharacterDataChanged. |aContainer| must be non-null; when
1.134 + // the container is null, no work is needed.
1.135 + void RestyleForInsertOrChange(Element* aContainer, nsIContent* aChild);
1.136 +
1.137 + // This would be the same as RestyleForInsertOrChange if we got the
1.138 + // notification before the removal. However, we get it after, so we need the
1.139 + // following sibling in addition to the old child. |aContainer| must be
1.140 + // non-null; when the container is null, no work is needed. aFollowingSibling
1.141 + // is the sibling that used to come after aOldChild before the removal.
1.142 + void RestyleForRemove(Element* aContainer,
1.143 + nsIContent* aOldChild,
1.144 + nsIContent* aFollowingSibling);
1.145 +
1.146 + // Same for a ContentAppended. |aContainer| must be non-null; when
1.147 + // the container is null, no work is needed.
1.148 + void RestyleForAppend(Element* aContainer, nsIContent* aFirstNewContent);
1.149 +
1.150 + // Process any pending restyles. This should be called after
1.151 + // CreateNeededFrames.
1.152 + // Note: It's the caller's responsibility to make sure to wrap a
1.153 + // ProcessPendingRestyles call in a view update batch and a script blocker.
1.154 + // This function does not call ProcessAttachedQueue() on the binding manager.
1.155 + // If the caller wants that to happen synchronously, it needs to handle that
1.156 + // itself.
1.157 + void ProcessPendingRestyles();
1.158 +
1.159 + // ProcessPendingRestyles calls into one of our RestyleTracker
1.160 + // objects. It then calls back to these functions at the beginning
1.161 + // and end of its work.
1.162 + void BeginProcessingRestyles();
1.163 + void EndProcessingRestyles();
1.164 +
1.165 + // Rebuilds all style data by throwing out the old rule tree and
1.166 + // building a new one, and additionally applying aExtraHint (which
1.167 + // must not contain nsChangeHint_ReconstructFrame) to the root frame.
1.168 + void RebuildAllStyleData(nsChangeHint aExtraHint);
1.169 +
1.170 + // Helper that does part of the work of RebuildAllStyleData, shared by
1.171 + // RestyleElement for 'rem' handling.
1.172 + void DoRebuildAllStyleData(RestyleTracker& aRestyleTracker,
1.173 + nsChangeHint aExtraHint);
1.174 +
1.175 + // See PostRestyleEventCommon below.
1.176 + void PostRestyleEvent(Element* aElement,
1.177 + nsRestyleHint aRestyleHint,
1.178 + nsChangeHint aMinChangeHint)
1.179 + {
1.180 + if (mPresContext) {
1.181 + PostRestyleEventCommon(aElement, aRestyleHint, aMinChangeHint,
1.182 + mPresContext->IsProcessingAnimationStyleChange());
1.183 + }
1.184 + }
1.185 +
1.186 + // See PostRestyleEventCommon below.
1.187 + void PostAnimationRestyleEvent(Element* aElement,
1.188 + nsRestyleHint aRestyleHint,
1.189 + nsChangeHint aMinChangeHint)
1.190 + {
1.191 + PostRestyleEventCommon(aElement, aRestyleHint, aMinChangeHint, true);
1.192 + }
1.193 +
1.194 + void PostRestyleEventForLazyConstruction()
1.195 + {
1.196 + PostRestyleEventInternal(true);
1.197 + }
1.198 +
1.199 + void FlushOverflowChangedTracker()
1.200 + {
1.201 + mOverflowChangedTracker.Flush();
1.202 + }
1.203 +
1.204 +private:
1.205 + /**
1.206 + * Notify the frame constructor that an element needs to have its
1.207 + * style recomputed.
1.208 + * @param aElement: The element to be restyled.
1.209 + * @param aRestyleHint: Which nodes need to have selector matching run
1.210 + * on them.
1.211 + * @param aMinChangeHint: A minimum change hint for aContent and its
1.212 + * descendants.
1.213 + * @param aForAnimation: Whether the style should be computed with or
1.214 + * without animation data. Animation code
1.215 + * sometimes needs to pass true; other code
1.216 + * should generally pass the the pres context's
1.217 + * IsProcessingAnimationStyleChange() value
1.218 + * (which is the default value).
1.219 + */
1.220 + void PostRestyleEventCommon(Element* aElement,
1.221 + nsRestyleHint aRestyleHint,
1.222 + nsChangeHint aMinChangeHint,
1.223 + bool aForAnimation);
1.224 + void PostRestyleEventInternal(bool aForLazyConstruction);
1.225 +
1.226 +public:
1.227 + /**
1.228 + * Asynchronously clear style data from the root frame downwards and ensure
1.229 + * it will all be rebuilt. This is safe to call anytime; it will schedule
1.230 + * a restyle and take effect next time style changes are flushed.
1.231 + * This method is used to recompute the style data when some change happens
1.232 + * outside of any style rules, like a color preference change or a change
1.233 + * in a system font size, or to fix things up when an optimization in the
1.234 + * style data has become invalid. We assume that the root frame will not
1.235 + * need to be reframed.
1.236 + */
1.237 + void PostRebuildAllStyleDataEvent(nsChangeHint aExtraHint);
1.238 +
1.239 +private:
1.240 + /* aMinHint is the minimal change that should be made to the element */
1.241 + // XXXbz do we really need the aPrimaryFrame argument here?
1.242 + void RestyleElement(Element* aElement,
1.243 + nsIFrame* aPrimaryFrame,
1.244 + nsChangeHint aMinHint,
1.245 + RestyleTracker& aRestyleTracker,
1.246 + bool aRestyleDescendants);
1.247 +
1.248 + nsresult StyleChangeReflow(nsIFrame* aFrame, nsChangeHint aHint);
1.249 +
1.250 + // Returns true if this function managed to successfully move a frame, and
1.251 + // false if it could not process the position change, and a reflow should
1.252 + // be performed instead.
1.253 + bool RecomputePosition(nsIFrame* aFrame);
1.254 +
1.255 +private:
1.256 + nsPresContext* mPresContext; // weak, disconnected in Disconnect
1.257 +
1.258 + bool mRebuildAllStyleData : 1;
1.259 + // True if we're already waiting for a refresh notification
1.260 + bool mObservingRefreshDriver : 1;
1.261 + // True if we're in the middle of a nsRefreshDriver refresh
1.262 + bool mInStyleRefresh : 1;
1.263 + uint32_t mHoverGeneration;
1.264 + nsChangeHint mRebuildAllExtraHint;
1.265 +
1.266 + OverflowChangedTracker mOverflowChangedTracker;
1.267 +
1.268 + // The total number of animation flushes by this frame constructor.
1.269 + // Used to keep the layer and animation manager in sync.
1.270 + uint64_t mAnimationGeneration;
1.271 +
1.272 + RestyleTracker mPendingRestyles;
1.273 + RestyleTracker mPendingAnimationRestyles;
1.274 +};
1.275 +
1.276 +/**
1.277 + * An ElementRestyler is created for *each* element in a subtree that we
1.278 + * recompute styles for.
1.279 + */
1.280 +class ElementRestyler MOZ_FINAL {
1.281 +public:
1.282 + typedef mozilla::dom::Element Element;
1.283 +
1.284 + // Construct for the root of the subtree that we're restyling.
1.285 + ElementRestyler(nsPresContext* aPresContext,
1.286 + nsIFrame* aFrame,
1.287 + nsStyleChangeList* aChangeList,
1.288 + nsChangeHint aHintsHandledByAncestors,
1.289 + RestyleTracker& aRestyleTracker,
1.290 + TreeMatchContext& aTreeMatchContext,
1.291 + nsTArray<nsIContent*>& aVisibleKidsOfHiddenElement);
1.292 +
1.293 + // Construct for an element whose parent is being restyled.
1.294 + enum ConstructorFlags {
1.295 + FOR_OUT_OF_FLOW_CHILD = 1<<0
1.296 + };
1.297 + ElementRestyler(const ElementRestyler& aParentRestyler,
1.298 + nsIFrame* aFrame,
1.299 + uint32_t aConstructorFlags);
1.300 +
1.301 + // Construct for a frame whose parent is being restyled, but whose
1.302 + // style context is the parent style context for its parent frame.
1.303 + // (This is only used for table frames, whose style contexts are used
1.304 + // as the parent style context for their outer table frame (table
1.305 + // wrapper frame). We should probably try to get rid of this
1.306 + // exception and have the inheritance go the other way.)
1.307 + enum ParentContextFromChildFrame { PARENT_CONTEXT_FROM_CHILD_FRAME };
1.308 + ElementRestyler(ParentContextFromChildFrame,
1.309 + const ElementRestyler& aParentFrameRestyler,
1.310 + nsIFrame* aFrame);
1.311 +
1.312 + /**
1.313 + * Restyle our frame's element and its subtree.
1.314 + *
1.315 + * Use eRestyle_Self for the aRestyleHint argument to mean
1.316 + * "reresolve our style context but not kids", use eRestyle_Subtree
1.317 + * to mean "reresolve our style context and kids", and use
1.318 + * nsRestyleHint(0) to mean recompute a new style context for our
1.319 + * current parent and existing rulenode, and the same for kids.
1.320 + */
1.321 + void Restyle(nsRestyleHint aRestyleHint);
1.322 +
1.323 + /**
1.324 + * mHintsHandled changes over time; it starts off as the hints that
1.325 + * have been handled by ancestors, and by the end of Restyle it
1.326 + * represents the hints that have been handled for this frame. This
1.327 + * method is intended to be called after Restyle, to find out what
1.328 + * hints have been handled for this frame.
1.329 + */
1.330 + nsChangeHint HintsHandledForFrame() { return mHintsHandled; }
1.331 +
1.332 +private:
1.333 + /**
1.334 + * First half of Restyle().
1.335 + */
1.336 + void RestyleSelf(nsIFrame* aSelf, nsRestyleHint aRestyleHint);
1.337 +
1.338 + /**
1.339 + * Restyle the children of this frame (and, in turn, their children).
1.340 + *
1.341 + * Second half of Restyle().
1.342 + */
1.343 + void RestyleChildren(nsRestyleHint aChildRestyleHint);
1.344 +
1.345 + /**
1.346 + * Helper for RestyleSelf().
1.347 + */
1.348 + void CaptureChange(nsStyleContext* aOldContext,
1.349 + nsStyleContext* aNewContext,
1.350 + nsChangeHint aChangeToAssume);
1.351 +
1.352 + /**
1.353 + * Helpers for RestyleChildren().
1.354 + */
1.355 + void RestyleUndisplayedChildren(nsRestyleHint aChildRestyleHint);
1.356 + void RestyleBeforePseudo();
1.357 + void RestyleAfterPseudo(nsIFrame* aFrame);
1.358 + void RestyleContentChildren(nsIFrame* aParent,
1.359 + nsRestyleHint aChildRestyleHint);
1.360 + void InitializeAccessibilityNotifications();
1.361 + void SendAccessibilityNotifications();
1.362 +
1.363 + enum DesiredA11yNotifications {
1.364 + eSkipNotifications,
1.365 + eSendAllNotifications,
1.366 + eNotifyIfShown
1.367 + };
1.368 +
1.369 + enum A11yNotificationType {
1.370 + eDontNotify,
1.371 + eNotifyShown,
1.372 + eNotifyHidden
1.373 + };
1.374 +
1.375 +private:
1.376 + nsPresContext* const mPresContext;
1.377 + nsIFrame* const mFrame;
1.378 + nsIContent* const mParentContent;
1.379 + // |mContent| is the node that we used for rule matching of
1.380 + // normal elements (not pseudo-elements) and for which we generate
1.381 + // framechange hints if we need them.
1.382 + nsIContent* const mContent;
1.383 + nsStyleChangeList* const mChangeList;
1.384 + // We have already generated change list entries for hints listed in
1.385 + // mHintsHandled (initially it's those handled by ancestors, but by
1.386 + // the end of Restyle it is those handled for this frame as well). We
1.387 + // need to generate a new change list entry for the frame when its
1.388 + // style comparision returns a hint other than one of these hints.
1.389 + nsChangeHint mHintsHandled;
1.390 + // See nsStyleContext::CalcStyleDifference
1.391 + nsChangeHint mParentFrameHintsNotHandledForDescendants;
1.392 + nsChangeHint mHintsNotHandledForDescendants;
1.393 + RestyleTracker& mRestyleTracker;
1.394 + TreeMatchContext& mTreeMatchContext;
1.395 + nsIFrame* mResolvedChild; // child that provides our parent style context
1.396 +
1.397 +#ifdef ACCESSIBILITY
1.398 + const DesiredA11yNotifications mDesiredA11yNotifications;
1.399 + DesiredA11yNotifications mKidsDesiredA11yNotifications;
1.400 + A11yNotificationType mOurA11yNotification;
1.401 + nsTArray<nsIContent*>& mVisibleKidsOfHiddenElement;
1.402 + bool mWasFrameVisible;
1.403 +#endif
1.404 +};
1.405 +
1.406 +} // namespace mozilla
1.407 +
1.408 +#endif /* mozilla_RestyleManager_h */
