gecko-dev/layout/base/ServoRestyleManager.h
Emilio Cobos Álvarez f14389a065 Bug 1422654: stylo: Avoid restyling XBL-bound element if the binding doesn't have stylesheets. r=heycam
MozReview-Commit-ID: An2McUbpCLk

--HG--
extra : rebase_source : 1c869057d032773fbfd426d6f392cc936c81029c
2017-12-04 02:47:54 +01:00

363 lines
14 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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/. */
#ifndef mozilla_ServoRestyleManager_h
#define mozilla_ServoRestyleManager_h
#include "mozilla/EventStates.h"
#include "mozilla/RestyleManager.h"
#include "mozilla/Maybe.h"
#include "mozilla/ServoElementSnapshot.h"
#include "mozilla/ServoElementSnapshotTable.h"
#include "nsChangeHint.h"
#include "nsPresContext.h"
namespace mozilla {
namespace dom {
class Element;
} // namespace dom
} // namespace mozilla
class nsAttrValue;
class nsAtom;
class nsIContent;
class nsIFrame;
class nsStyleChangeList;
namespace mozilla {
/**
* A stack class used to pass some common restyle state in a slightly more
* comfortable way than a bunch of individual arguments, and that also checks
* that the change hint used for optimization is correctly used in debug mode.
*/
class ServoRestyleState
{
public:
ServoRestyleState(ServoStyleSet& aStyleSet, nsStyleChangeList& aChangeList,
nsTArray<nsIFrame*>& aPendingWrapperRestyles)
: mStyleSet(aStyleSet)
, mChangeList(aChangeList)
, mPendingWrapperRestyles(aPendingWrapperRestyles)
, mPendingWrapperRestyleOffset(aPendingWrapperRestyles.Length())
, mChangesHandled(nsChangeHint(0))
#ifdef DEBUG
// If !mOwner, then we wouldn't have processed our wrapper restyles, because
// we only process those when handling an element with a frame. But that's
// OK, because if we started our traversal at an element with no frame
// (e.g. it's display:contents), that means the wrapper frames in our list
// actually inherit from one of its ancestors, not from it, and hence not
// restyling them is OK.
, mAssertWrapperRestyleLength(false)
#endif // DEBUG
{}
// We shouldn't assume that changes handled from our parent are handled for
// our children too if we're out of flow since they aren't necessarily
// parented in DOM order, and thus a change handled by a DOM ancestor doesn't
// necessarily mean that it's handled for an ancestor frame.
enum class Type
{
InFlow,
OutOfFlow,
};
ServoRestyleState(const nsIFrame& aOwner,
ServoRestyleState& aParentState,
nsChangeHint aHintForThisFrame,
Type aType,
bool aAssertWrapperRestyleLength = true)
: mStyleSet(aParentState.mStyleSet)
, mChangeList(aParentState.mChangeList)
, mPendingWrapperRestyles(aParentState.mPendingWrapperRestyles)
, mPendingWrapperRestyleOffset(aParentState.mPendingWrapperRestyles.Length())
, mChangesHandled(
aType == Type::InFlow
? aParentState.mChangesHandled | aHintForThisFrame
: aHintForThisFrame)
#ifdef DEBUG
, mOwner(&aOwner)
, mAssertWrapperRestyleLength(aAssertWrapperRestyleLength)
#endif
{
if (aType == Type::InFlow) {
AssertOwner(aParentState);
}
}
~ServoRestyleState() {
MOZ_ASSERT(!mAssertWrapperRestyleLength ||
mPendingWrapperRestyles.Length() == mPendingWrapperRestyleOffset,
"Someone forgot to call ProcessWrapperRestyles!");
}
nsStyleChangeList& ChangeList() { return mChangeList; }
ServoStyleSet& StyleSet() { return mStyleSet; }
#ifdef DEBUG
void AssertOwner(const ServoRestyleState& aParentState) const;
nsChangeHint ChangesHandledFor(const nsIFrame&) const;
#else
void AssertOwner(const ServoRestyleState&) const {}
nsChangeHint ChangesHandledFor(const nsIFrame&) const
{
return mChangesHandled;
}
#endif
// Add a pending wrapper restyle. We don't have to do anything if the thing
// being added is already last in the list, but otherwise we do want to add
// it, in order for ProcessWrapperRestyles to work correctly.
void AddPendingWrapperRestyle(nsIFrame* aWrapperFrame);
// Process wrapper restyles for this restyle state. This should be done
// before it comes off the stack.
void ProcessWrapperRestyles(nsIFrame* aParentFrame);
// Get the table-aware parent for the given child. This will walk through
// outer table and cellcontent frames.
static nsIFrame* TableAwareParentFor(const nsIFrame* aChild);
private:
// Process a wrapper restyle at the given index, and restyles for any
// wrappers nested in it. Returns the number of entries from
// mPendingWrapperRestyles that we processed. The return value is always at
// least 1.
size_t ProcessMaybeNestedWrapperRestyle(nsIFrame* aParent, size_t aIndex);
ServoStyleSet& mStyleSet;
nsStyleChangeList& mChangeList;
// A list of pending wrapper restyles. Anonymous box wrapper frames that need
// restyling are added to this list when their non-anonymous kids are
// restyled. This avoids us having to do linear searches along the frame tree
// for these anonymous boxes. The problem then becomes that we can have
// multiple kids all with the same anonymous parent, and we don't want to
// restyle it more than once. We use mPendingWrapperRestyles to track which
// anonymous wrapper boxes we've requested be restyled and which of them have
// already been restyled. We use a single array propagated through
// ServoRestyleStates by reference, because in a situation like this:
//
// <div style="display: table"><span></span></div>
//
// We have multiple wrappers to restyle (cell, row, table-row-group) and we
// want to add them in to the list all at once but restyle them using
// different ServoRestyleStates with different owners. When this situation
// occurs, the relevant frames will be placed in the array with ancestors
// before descendants.
nsTArray<nsIFrame*>& mPendingWrapperRestyles;
// Since we're given a possibly-nonempty mPendingWrapperRestyles to start
// with, we need to keep track of where the part of it we're responsible for
// starts.
size_t mPendingWrapperRestyleOffset;
const nsChangeHint mChangesHandled;
// We track the "owner" frame of this restyle state, that is, the frame that
// generated the last change that is stored in mChangesHandled, in order to
// verify that we only use mChangesHandled for actual descendants of that
// frame (given DOM order isn't always frame order, and that there are a few
// special cases for stuff like wrapper frames, ::backdrop, and so on).
#ifdef DEBUG
const nsIFrame* mOwner { nullptr };
#endif
// Whether we should assert in our destructor that we've processed all of the
// relevant wrapper restyles.
#ifdef DEBUG
const bool mAssertWrapperRestyleLength;
#endif // DEBUG
};
enum class ServoPostTraversalFlags : uint32_t;
/**
* Restyle manager for a Servo-backed style system.
*/
class ServoRestyleManager : public RestyleManager
{
friend class ServoStyleSet;
public:
typedef ServoElementSnapshotTable SnapshotTable;
typedef RestyleManager base_type;
explicit ServoRestyleManager(nsPresContext* aPresContext);
void PostRestyleEvent(dom::Element* aElement,
nsRestyleHint aRestyleHint,
nsChangeHint aMinChangeHint);
void PostRestyleEventForCSSRuleChanges();
void RebuildAllStyleData(nsChangeHint aExtraHint,
nsRestyleHint aRestyleHint);
void PostRebuildAllStyleDataEvent(nsChangeHint aExtraHint,
nsRestyleHint aRestyleHint);
void ProcessPendingRestyles();
void ProcessAllPendingAttributeAndStateInvalidations();
bool HasPendingRestyleAncestor(dom::Element* aElement) const;
/**
* Performs a Servo animation-only traversal to compute style for all nodes
* with the animation-only dirty bit in the document.
*
* This processes just the traversal for animation-only restyles and skips the
* normal traversal for other restyles unrelated to animations.
* This is used to bring throttled animations up-to-date such as when we need
* to get correct position for transform animations that are throttled because
* they are running on the compositor.
*
* This will traverse all of the document's style roots (that is, its document
* element, and the roots of the document-level native anonymous content).
*/
void UpdateOnlyAnimationStyles();
void ContentStateChanged(nsIContent* aContent, EventStates aStateMask);
void AttributeWillChange(dom::Element* aElement,
int32_t aNameSpaceID,
nsAtom* aAttribute,
int32_t aModType,
const nsAttrValue* aNewValue);
void ClassAttributeWillBeChangedBySMIL(dom::Element* aElement);
void AttributeChanged(dom::Element* aElement, int32_t aNameSpaceID,
nsAtom* aAttribute, int32_t aModType,
const nsAttrValue* aOldValue);
// This is only used to reparent things when moving them in/out of the
// ::first-line. Once we get rid of the Gecko style system, we should rename
// this method accordingly (e.g. to ReparentStyleContextForFirstLine).
nsresult ReparentStyleContext(nsIFrame* aFrame);
private:
/**
* Reparent the descendants of aFrame. This is used by ReparentStyleContext
* and shouldn't be called by anyone else. aProviderChild, if non-null, is a
* child that was the style parent for aFrame and hence shouldn't be
* reparented.
*/
void ReparentFrameDescendants(nsIFrame* aFrame, nsIFrame* aProviderChild,
ServoStyleSet& aStyleSet);
public:
/**
* Whether to clear all the style data (including the element itself), or just
* the descendants' data.
*/
enum class IncludeRoot {
Yes,
No,
};
/**
* Clears the ServoElementData and HasDirtyDescendants from all elements
* in the subtree rooted at aElement.
*/
static void ClearServoDataFromSubtree(Element*, IncludeRoot = IncludeRoot::Yes);
/**
* Clears HasDirtyDescendants and RestyleData from all elements in the
* subtree rooted at aElement.
*/
static void ClearRestyleStateFromSubtree(Element* aElement);
/**
* Posts restyle hints for animations.
* This is only called for the second traversal for CSS animations during
* updating CSS animations in a SequentialTask.
* This function does neither register a refresh observer nor flag that a
* style flush is needed since this function is supposed to be called during
* restyling process and this restyle event will be processed in the second
* traversal of the same restyling process.
*/
void PostRestyleEventForAnimations(dom::Element* aElement,
CSSPseudoElementType aPseudoType,
nsRestyleHint aRestyleHint);
protected:
~ServoRestyleManager() override
{
MOZ_ASSERT(!mReentrantChanges);
}
private:
/**
* Performs post-Servo-traversal processing on this element and its
* descendants.
*
* Returns whether any style did actually change. There may be cases where we
* didn't need to change any style after all, for example, when a content
* attribute changes that happens not to have any effect on the style of that
* element or any descendant or sibling.
*/
bool ProcessPostTraversal(Element* aElement,
ServoStyleContext* aParentContext,
ServoRestyleState& aRestyleState,
ServoPostTraversalFlags aFlags);
struct TextPostTraversalState;
bool ProcessPostTraversalForText(nsIContent* aTextNode,
TextPostTraversalState& aState,
ServoRestyleState& aRestyleState,
ServoPostTraversalFlags aFlags);
inline ServoStyleSet* StyleSet() const
{
MOZ_ASSERT(PresContext()->StyleSet()->IsServo(),
"ServoRestyleManager should only be used with a Servo-flavored "
"style backend");
return PresContext()->StyleSet()->AsServo();
}
const SnapshotTable& Snapshots() const { return mSnapshots; }
void ClearSnapshots();
ServoElementSnapshot& SnapshotFor(mozilla::dom::Element* aElement);
void TakeSnapshotForAttributeChange(mozilla::dom::Element* aElement,
int32_t aNameSpaceID,
nsAtom* aAttribute);
void DoProcessPendingRestyles(ServoTraversalFlags aFlags);
// Function to do the actual (recursive) work of ReparentStyleContext, once we
// have asserted the invariants that only hold on the initial call.
void DoReparentStyleContext(nsIFrame* aFrame,
ServoStyleSet& aStyleSet);
// We use a separate data structure from nsStyleChangeList because we need a
// frame to create nsStyleChangeList entries, and the primary frame may not be
// attached yet.
struct ReentrantChange {
nsCOMPtr<nsIContent> mContent;
nsChangeHint mHint;
};
typedef AutoTArray<ReentrantChange, 10> ReentrantChangeList;
// Only non-null while processing change hints. See the comment in
// ProcessPendingRestyles.
ReentrantChangeList* mReentrantChanges;
// We use this flag to track if the current restyle contains any non-animation
// update, which triggers a normal restyle, and so there might be any new
// transition created later. Therefore, if this flag is true, we need to
// increase mAnimationGeneration before creating new transitions, so their
// creation sequence will be correct.
bool mHaveNonAnimationRestyles = false;
// Set to true when posting restyle events triggered by CSS rule changes.
// This flag is cleared once ProcessPendingRestyles has completed.
// When we process a traversal all descendants elements of the document
// triggered by CSS rule changes, we will need to update all elements with
// CSS animations. We propagate TraversalRestyleBehavior::ForCSSRuleChanges
// to traversal function if this flag is set.
bool mRestyleForCSSRuleChanges = false;
// A hashtable with the elements that have changed state or attributes, in
// order to calculate restyle hints during the traversal.
SnapshotTable mSnapshots;
};
} // namespace mozilla
#endif // mozilla_ServoRestyleManager_h