gecko-dev/layout/base/RestyleManager.h

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/**
* Code responsible for managing style changes: tracking what style
* changes need to happen, scheduling them, and doing them.
*/
#ifndef mozilla_RestyleManager_h
#define mozilla_RestyleManager_h
#include "mozilla/RestyleLogging.h"
#include "nsISupportsImpl.h"
#include "nsChangeHint.h"
#include "RestyleTracker.h"
#include "nsPresContext.h"
#include "nsRefreshDriver.h"
#include "nsRefPtrHashtable.h"
#include "nsCSSPseudoElements.h"
class nsIFrame;
class nsStyleChangeList;
struct TreeMatchContext;
namespace mozilla {
class EventStates;
namespace dom {
class Element;
} // namespace dom
class RestyleManager MOZ_FINAL {
public:
friend class ::nsRefreshDriver;
friend class RestyleTracker;
typedef mozilla::dom::Element Element;
explicit RestyleManager(nsPresContext* aPresContext);
private:
// Private destructor, to discourage deletion outside of Release():
~RestyleManager()
{
MOZ_ASSERT(!mReframingStyleContexts,
"temporary member should be nulled out before destruction");
}
public:
NS_INLINE_DECL_REFCOUNTING(mozilla::RestyleManager)
void Disconnect() {
mPresContext = nullptr;
}
nsPresContext* PresContext() const {
MOZ_ASSERT(mPresContext);
return mPresContext;
}
nsCSSFrameConstructor* FrameConstructor() const
{ return PresContext()->FrameConstructor(); }
// Should be called when a frame is going to be destroyed and
// WillDestroyFrameTree hasn't been called yet.
void NotifyDestroyingFrame(nsIFrame* aFrame);
// Forwarded nsIDocumentObserver method, to handle restyling (and
// passing the notification to the frame).
nsresult ContentStateChanged(nsIContent* aContent,
EventStates aStateMask);
// Forwarded nsIMutationObserver method, to handle restyling.
void AttributeWillChange(Element* aElement,
int32_t aNameSpaceID,
nsIAtom* aAttribute,
int32_t aModType);
// Forwarded nsIMutationObserver method, to handle restyling (and
// passing the notification to the frame).
void AttributeChanged(Element* aElement,
int32_t aNameSpaceID,
nsIAtom* aAttribute,
int32_t aModType);
// Get an integer that increments every time there is a style change
// as a result of a change to the :hover content state.
uint32_t GetHoverGeneration() const { return mHoverGeneration; }
// Get a counter that increments on every style change, that we use to
// track whether off-main-thread animations are up-to-date.
uint64_t GetAnimationGeneration() const { return mAnimationGeneration; }
// Whether rule matching should skip styles associated with animation
bool SkipAnimationRules() const {
MOZ_ASSERT(mSkipAnimationRules || !mPostAnimationRestyles,
"inconsistent state");
return mSkipAnimationRules;
}
// Whether rule matching should post animation restyles when it skips
// styles associated with animation. Only true when
// SkipAnimationRules() is also true.
bool PostAnimationRestyles() const {
MOZ_ASSERT(mSkipAnimationRules || !mPostAnimationRestyles,
"inconsistent state");
return mPostAnimationRestyles;
}
// Whether we're currently in the animation phase of restyle
// processing (to be eliminated in bug 960465)
bool IsProcessingAnimationStyleChange() const {
return mIsProcessingAnimationStyleChange;
}
/**
* Reparent the style contexts of this frame subtree. The parent frame of
* aFrame must be changed to the new parent before this function is called;
* the new parent style context will be automatically computed based on the
* new position in the frame tree.
*
* @param aFrame the root of the subtree to reparent. Must not be null.
*/
nsresult ReparentStyleContext(nsIFrame* aFrame);
private:
void ComputeAndProcessStyleChange(nsIFrame* aFrame,
nsChangeHint aMinChange,
RestyleTracker& aRestyleTracker,
nsRestyleHint aRestyleHint);
/**
* Re-resolve the style contexts for a frame tree, building
* aChangeList based on the resulting style changes, plus aMinChange
* applied to aFrame.
*/
void
ComputeStyleChangeFor(nsIFrame* aFrame,
nsStyleChangeList* aChangeList,
nsChangeHint aMinChange,
RestyleTracker& aRestyleTracker,
nsRestyleHint aRestyleHint);
public:
#ifdef DEBUG
/**
* DEBUG ONLY method to verify integrity of style tree versus frame tree
*/
void DebugVerifyStyleTree(nsIFrame* aFrame);
#endif
// Note: It's the caller's responsibility to make sure to wrap a
// ProcessRestyledFrames call in a view update batch and a script blocker.
// This function does not call ProcessAttachedQueue() on the binding manager.
// If the caller wants that to happen synchronously, it needs to handle that
// itself.
nsresult ProcessRestyledFrames(nsStyleChangeList& aRestyleArray);
/**
* In order to start CSS transitions on elements that are being
* reframed, we need to stash their style contexts somewhere during
* the reframing process.
*
* In all cases, the content node in the hash table is the real
* content node, not the anonymous content node we create for ::before
* or ::after. The content node passed to the Get and Put methods is,
* however, the content node to be associate with the frame's style
* context.
*/
typedef nsRefPtrHashtable<nsRefPtrHashKey<nsIContent>, nsStyleContext>
ReframingStyleContextTable;
class ReframingStyleContexts {
public:
void Put(nsIContent* aContent, nsStyleContext* aStyleContext) {
MOZ_ASSERT(aContent);
nsCSSPseudoElements::Type pseudoType = aStyleContext->GetPseudoType();
if (pseudoType == nsCSSPseudoElements::ePseudo_NotPseudoElement) {
mElementContexts.Put(aContent, aStyleContext);
} else if (pseudoType == nsCSSPseudoElements::ePseudo_before) {
MOZ_ASSERT(aContent->Tag() == nsGkAtoms::mozgeneratedcontentbefore);
mBeforePseudoContexts.Put(aContent->GetParent(), aStyleContext);
} else if (pseudoType == nsCSSPseudoElements::ePseudo_after) {
MOZ_ASSERT(aContent->Tag() == nsGkAtoms::mozgeneratedcontentafter);
mAfterPseudoContexts.Put(aContent->GetParent(), aStyleContext);
}
}
nsStyleContext* Get(nsIContent* aContent,
nsCSSPseudoElements::Type aPseudoType) {
MOZ_ASSERT(aContent);
if (aPseudoType == nsCSSPseudoElements::ePseudo_NotPseudoElement) {
return mElementContexts.GetWeak(aContent);
}
if (aPseudoType == nsCSSPseudoElements::ePseudo_before) {
MOZ_ASSERT(aContent->Tag() == nsGkAtoms::mozgeneratedcontentbefore);
return mBeforePseudoContexts.GetWeak(aContent->GetParent());
}
if (aPseudoType == nsCSSPseudoElements::ePseudo_after) {
MOZ_ASSERT(aContent->Tag() == nsGkAtoms::mozgeneratedcontentafter);
return mAfterPseudoContexts.GetWeak(aContent->GetParent());
}
MOZ_ASSERT(false, "unexpected aPseudoType");
return nullptr;
}
private:
ReframingStyleContextTable mElementContexts;
ReframingStyleContextTable mBeforePseudoContexts;
ReframingStyleContextTable mAfterPseudoContexts;
};
/**
* Return the current ReframingStyleContexts struct, or null if we're
* not currently in a restyling operation.
*/
ReframingStyleContexts* GetReframingStyleContexts() {
return mReframingStyleContexts;
}
/**
* Try starting a transition for an element or a ::before or ::after
* pseudo-element, given an old and new style context. This may
* change the new style context if a transition is started.
*
* For the pseudo-elements, aContent must be the anonymous content
* that we're creating for that pseudo-element, not the real element.
*/
static void
TryStartingTransition(nsPresContext* aPresContext, nsIContent* aContent,
nsStyleContext* aOldStyleContext,
nsRefPtr<nsStyleContext>* aNewStyleContext /* inout */);
private:
void RestyleForEmptyChange(Element* aContainer);
public:
// Restyling for a ContentInserted (notification after insertion) or
// for a CharacterDataChanged. |aContainer| must be non-null; when
// the container is null, no work is needed.
void RestyleForInsertOrChange(Element* aContainer, nsIContent* aChild);
// This would be the same as RestyleForInsertOrChange if we got the
// notification before the removal. However, we get it after, so we need the
// following sibling in addition to the old child. |aContainer| must be
// non-null; when the container is null, no work is needed. aFollowingSibling
// is the sibling that used to come after aOldChild before the removal.
void RestyleForRemove(Element* aContainer,
nsIContent* aOldChild,
nsIContent* aFollowingSibling);
// Same for a ContentAppended. |aContainer| must be non-null; when
// the container is null, no work is needed.
void RestyleForAppend(Element* aContainer, nsIContent* aFirstNewContent);
// Process any pending restyles. This should be called after
// CreateNeededFrames.
// Note: It's the caller's responsibility to make sure to wrap a
// ProcessPendingRestyles call in a view update batch and a script blocker.
// This function does not call ProcessAttachedQueue() on the binding manager.
// If the caller wants that to happen synchronously, it needs to handle that
// itself.
void ProcessPendingRestyles();
// Returns whether there are any pending restyles.
bool HasPendingRestyles() { return mPendingRestyles.Count() != 0; }
// ProcessPendingRestyles calls into one of our RestyleTracker
// objects. It then calls back to these functions at the beginning
// and end of its work.
void BeginProcessingRestyles();
void EndProcessingRestyles();
// Update styles for animations that are running on the compositor and
// whose updating is suppressed on the main thread (to save
// unnecessary work), while leaving all other aspects of style
// out-of-date.
//
// Performs an animation-only style flush to make styles from
// throttled transitions up-to-date prior to processing an unrelated
// style change, so that any transitions triggered by that style
// change produce correct results.
//
// In more detail: when we're able to run animations on the
// compositor, we sometimes "throttle" these animations by skipping
// updating style data on the main thread. However, whenever we
// process a normal (non-animation) style change, any changes in
// computed style on elements that have transition-* properties set
// may need to trigger new transitions; this process requires knowing
// both the old and new values of the property. To do this correctly,
// we need to have an up-to-date *old* value of the property on the
// primary frame. So the purpose of the mini-flush is to update the
// style for all throttled transitions and animations to the current
// animation state without making any other updates, so that when we
// process the queued style updates we'll have correct old data to
// compare against. When we do this, we don't bother touching frames
// other than primary frames.
void UpdateOnlyAnimationStyles();
bool ThrottledAnimationStyleIsUpToDate() const {
return mLastUpdateForThrottledAnimations ==
mPresContext->RefreshDriver()->MostRecentRefresh();
}
// Rebuilds all style data by throwing out the old rule tree and
// building a new one, and additionally applying aExtraHint (which
// must not contain nsChangeHint_ReconstructFrame) to the root frame.
void RebuildAllStyleData(nsChangeHint aExtraHint);
// Helper that does part of the work of RebuildAllStyleData, shared by
// RestyleElement for 'rem' handling.
void DoRebuildAllStyleData(RestyleTracker& aRestyleTracker,
nsChangeHint aExtraHint,
nsRestyleHint aRestyleHint);
// See PostRestyleEventCommon below.
void PostRestyleEvent(Element* aElement,
nsRestyleHint aRestyleHint,
nsChangeHint aMinChangeHint)
{
if (mPresContext) {
PostRestyleEventCommon(aElement, aRestyleHint, aMinChangeHint,
IsProcessingAnimationStyleChange());
}
}
// See PostRestyleEventCommon below.
void PostAnimationRestyleEvent(Element* aElement,
nsRestyleHint aRestyleHint,
nsChangeHint aMinChangeHint)
{
PostRestyleEventCommon(aElement, aRestyleHint, aMinChangeHint, true);
}
void PostRestyleEventForLazyConstruction()
{
PostRestyleEventInternal(true);
}
void FlushOverflowChangedTracker()
{
mOverflowChangedTracker.Flush();
}
#ifdef DEBUG
static nsCString RestyleHintToString(nsRestyleHint aHint);
static nsCString ChangeHintToString(nsChangeHint aHint);
#endif
private:
/**
* Notify the frame constructor that an element needs to have its
* style recomputed.
* @param aElement: The element to be restyled.
* @param aRestyleHint: Which nodes need to have selector matching run
* on them.
* @param aMinChangeHint: A minimum change hint for aContent and its
* descendants.
* @param aForAnimation: Whether the style should be computed with or
* without animation data. Animation code
* sometimes needs to pass true; other code
* should generally pass the the pres context's
* IsProcessingAnimationStyleChange() value
* (which is the default value).
*/
void PostRestyleEventCommon(Element* aElement,
nsRestyleHint aRestyleHint,
nsChangeHint aMinChangeHint,
bool aForAnimation);
void PostRestyleEventInternal(bool aForLazyConstruction);
public:
/**
* Asynchronously clear style data from the root frame downwards and ensure
* it will all be rebuilt. This is safe to call anytime; it will schedule
* a restyle and take effect next time style changes are flushed.
* This method is used to recompute the style data when some change happens
* outside of any style rules, like a color preference change or a change
* in a system font size, or to fix things up when an optimization in the
* style data has become invalid. We assume that the root frame will not
* need to be reframed.
*/
void PostRebuildAllStyleDataEvent(nsChangeHint aExtraHint);
#ifdef RESTYLE_LOGGING
/**
* Returns whether a restyle event currently being processed by this
* RestyleManager should be logged.
*/
bool ShouldLogRestyle() {
return ShouldLogRestyle(mPresContext);
}
/**
* Returns whether a restyle event currently being processed for the
* document with the specified nsPresContext should be logged.
*/
static bool ShouldLogRestyle(nsPresContext* aPresContext) {
return aPresContext->RestyleLoggingEnabled() &&
(!aPresContext->RestyleManager()->
IsProcessingAnimationStyleChange() ||
AnimationRestyleLoggingEnabled());
}
static bool RestyleLoggingInitiallyEnabled() {
static bool enabled = getenv("MOZ_DEBUG_RESTYLE") != 0;
return enabled;
}
static bool AnimationRestyleLoggingEnabled() {
static bool animations = getenv("MOZ_DEBUG_RESTYLE_ANIMATIONS") != 0;
return animations;
}
// Set MOZ_DEBUG_RESTYLE_STRUCTS to a comma-separated string of
// style struct names -- such as "Font,SVGReset" -- to log the style context
// tree and those cached struct pointers before each restyle. This
// function returns a bitfield of the structs named in the
// environment variable.
static uint32_t StructsToLog();
static nsCString StructNamesToString(uint32_t aSIDs);
int32_t& LoggingDepth() { return mLoggingDepth; }
#endif
private:
/* aMinHint is the minimal change that should be made to the element */
// XXXbz do we really need the aPrimaryFrame argument here?
void RestyleElement(Element* aElement,
nsIFrame* aPrimaryFrame,
nsChangeHint aMinHint,
RestyleTracker& aRestyleTracker,
nsRestyleHint aRestyleHint);
void StyleChangeReflow(nsIFrame* aFrame, nsChangeHint aHint);
// Recursively add all the given frame and all children to the tracker.
void AddSubtreeToOverflowTracker(nsIFrame* aFrame);
// Returns true if this function managed to successfully move a frame, and
// false if it could not process the position change, and a reflow should
// be performed instead.
bool RecomputePosition(nsIFrame* aFrame);
private:
nsPresContext* mPresContext; // weak, disconnected in Disconnect
bool mRebuildAllStyleData : 1;
// True if we're already waiting for a refresh notification
bool mObservingRefreshDriver : 1;
// True if we're in the middle of a nsRefreshDriver refresh
bool mInStyleRefresh : 1;
// Whether rule matching should skip styles associated with animation
bool mSkipAnimationRules : 1;
// Whether rule matching should post animation restyles when it skips
// styles associated with animation. Only true when
// mSkipAnimationRules is also true.
bool mPostAnimationRestyles : 1;
// Whether we're currently in the animation phase of restyle
// processing (to be eliminated in bug 960465)
bool mIsProcessingAnimationStyleChange : 1;
uint32_t mHoverGeneration;
nsChangeHint mRebuildAllExtraHint;
mozilla::TimeStamp mLastUpdateForThrottledAnimations;
OverflowChangedTracker mOverflowChangedTracker;
// The total number of animation flushes by this frame constructor.
// Used to keep the layer and animation manager in sync.
uint64_t mAnimationGeneration;
ReframingStyleContexts* mReframingStyleContexts;
RestyleTracker mPendingRestyles;
RestyleTracker mPendingAnimationRestyles;
#ifdef DEBUG
bool mIsProcessingRestyles;
#endif
#ifdef RESTYLE_LOGGING
int32_t mLoggingDepth;
#endif
};
/**
* An ElementRestyler is created for *each* element in a subtree that we
* recompute styles for.
*/
class ElementRestyler MOZ_FINAL {
public:
typedef mozilla::dom::Element Element;
// Construct for the root of the subtree that we're restyling.
ElementRestyler(nsPresContext* aPresContext,
nsIFrame* aFrame,
nsStyleChangeList* aChangeList,
nsChangeHint aHintsHandledByAncestors,
RestyleTracker& aRestyleTracker,
TreeMatchContext& aTreeMatchContext,
nsTArray<nsIContent*>& aVisibleKidsOfHiddenElement);
// Construct for an element whose parent is being restyled.
enum ConstructorFlags {
FOR_OUT_OF_FLOW_CHILD = 1<<0
};
ElementRestyler(const ElementRestyler& aParentRestyler,
nsIFrame* aFrame,
uint32_t aConstructorFlags);
// Construct for a frame whose parent is being restyled, but whose
// style context is the parent style context for its parent frame.
// (This is only used for table frames, whose style contexts are used
// as the parent style context for their outer table frame (table
// wrapper frame). We should probably try to get rid of this
// exception and have the inheritance go the other way.)
enum ParentContextFromChildFrame { PARENT_CONTEXT_FROM_CHILD_FRAME };
ElementRestyler(ParentContextFromChildFrame,
const ElementRestyler& aParentFrameRestyler,
nsIFrame* aFrame);
/**
* Restyle our frame's element and its subtree.
*
* Use eRestyle_Self for the aRestyleHint argument to mean
* "reresolve our style context but not kids", use eRestyle_Subtree
* to mean "reresolve our style context and kids", and use
* nsRestyleHint(0) to mean recompute a new style context for our
* current parent and existing rulenode, and the same for kids.
*/
void Restyle(nsRestyleHint aRestyleHint);
/**
* mHintsHandled changes over time; it starts off as the hints that
* have been handled by ancestors, and by the end of Restyle it
* represents the hints that have been handled for this frame. This
* method is intended to be called after Restyle, to find out what
* hints have been handled for this frame.
*/
nsChangeHint HintsHandledForFrame() { return mHintsHandled; }
#ifdef RESTYLE_LOGGING
bool ShouldLogRestyle() {
return RestyleManager::ShouldLogRestyle(mPresContext);
}
#endif
private:
// Enum for the result of RestyleSelf, which indicates whether the
// restyle procedure should continue to the children, and how.
//
// These values must be ordered so that later values imply that all
// the work of the earlier values is also done.
enum RestyleResult {
// do not restyle children
eRestyleResult_Stop = 1,
// continue restyling children
eRestyleResult_Continue,
// continue restyling children with eRestyle_ForceDescendants set
eRestyleResult_ContinueAndForceDescendants
};
/**
* First half of Restyle().
*/
RestyleResult RestyleSelf(nsIFrame* aSelf,
nsRestyleHint aRestyleHint,
uint32_t* aSwappedStructs);
/**
* Restyle the children of this frame (and, in turn, their children).
*
* Second half of Restyle().
*/
void RestyleChildren(nsRestyleHint aChildRestyleHint);
/**
* Helpers for RestyleSelf().
*/
void CaptureChange(nsStyleContext* aOldContext,
nsStyleContext* aNewContext,
nsChangeHint aChangeToAssume,
uint32_t* aEqualStructs);
RestyleResult ComputeRestyleResultFromFrame(nsIFrame* aSelf);
RestyleResult ComputeRestyleResultFromNewContext(nsIFrame* aSelf,
nsStyleContext* aNewContext);
/**
* Helpers for RestyleChildren().
*/
void RestyleUndisplayedChildren(nsRestyleHint aChildRestyleHint);
void MaybeReframeForBeforePseudo();
void MaybeReframeForAfterPseudo(nsIFrame* aFrame);
void RestyleContentChildren(nsIFrame* aParent,
nsRestyleHint aChildRestyleHint);
void InitializeAccessibilityNotifications();
void SendAccessibilityNotifications();
enum DesiredA11yNotifications {
eSkipNotifications,
eSendAllNotifications,
eNotifyIfShown
};
enum A11yNotificationType {
eDontNotify,
eNotifyShown,
eNotifyHidden
};
#ifdef RESTYLE_LOGGING
int32_t& LoggingDepth() { return mLoggingDepth; }
#endif
#ifdef DEBUG
static nsCString RestyleResultToString(RestyleResult aRestyleResult);
#endif
private:
nsPresContext* const mPresContext;
nsIFrame* const mFrame;
nsIContent* const mParentContent;
// |mContent| is the node that we used for rule matching of
// normal elements (not pseudo-elements) and for which we generate
// framechange hints if we need them.
nsIContent* const mContent;
nsStyleChangeList* const mChangeList;
// We have already generated change list entries for hints listed in
// mHintsHandled (initially it's those handled by ancestors, but by
// the end of Restyle it is those handled for this frame as well). We
// need to generate a new change list entry for the frame when its
// style comparision returns a hint other than one of these hints.
nsChangeHint mHintsHandled;
// See nsStyleContext::CalcStyleDifference
nsChangeHint mParentFrameHintsNotHandledForDescendants;
nsChangeHint mHintsNotHandledForDescendants;
RestyleTracker& mRestyleTracker;
TreeMatchContext& mTreeMatchContext;
nsIFrame* mResolvedChild; // child that provides our parent style context
#ifdef ACCESSIBILITY
const DesiredA11yNotifications mDesiredA11yNotifications;
DesiredA11yNotifications mKidsDesiredA11yNotifications;
A11yNotificationType mOurA11yNotification;
nsTArray<nsIContent*>& mVisibleKidsOfHiddenElement;
bool mWasFrameVisible;
#endif
#ifdef RESTYLE_LOGGING
int32_t mLoggingDepth;
#endif
};
} // namespace mozilla
#endif /* mozilla_RestyleManager_h */