The Tor Browser: layout/base/nsChangeHint.h@b8a032363ba2 (annotated)

layout/base/nsChangeHint.h@b8a032363ba2 (annotated)

layout/base/nsChangeHint.h

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /* -*- 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/. */
 /* constants for what needs to be recomputed in response to style changes */
 #ifndef nsChangeHint_h___
 #define nsChangeHint_h___
 #include "nsDebug.h"
 // Defines for various style related constants
 enum nsChangeHint {
   // change was visual only (e.g., COLOR=)
   // Invalidates all descendant frames (including following
   // placeholders to out-of-flow frames).
   nsChangeHint_RepaintFrame = 0x01,
   // For reflow, we want flags to give us arbitrary FrameNeedsReflow behavior.
   // just do a FrameNeedsReflow.
   nsChangeHint_NeedReflow = 0x02,
   // Invalidate intrinsic widths on the frame's ancestors.  Must not be set
   // without setting nsChangeHint_NeedReflow.
   nsChangeHint_ClearAncestorIntrinsics = 0x04,
   // Invalidate intrinsic widths on the frame's descendants.  Must not be set
   // without also setting nsChangeHint_ClearAncestorIntrinsics.
   nsChangeHint_ClearDescendantIntrinsics = 0x08,
   // Force unconditional reflow of all descendants.  Must not be set without
   // setting nsChangeHint_NeedReflow, but is independent of both the
   // Clear*Intrinsics flags.
   nsChangeHint_NeedDirtyReflow = 0x10,
   // change requires view to be updated, if there is one (e.g., clip:).
   // Updates all descendants (including following placeholders to out-of-flows).
   nsChangeHint_SyncFrameView = 0x20,
   // The currently shown mouse cursor needs to be updated
   nsChangeHint_UpdateCursor = 0x40,
   /**
    * Used when the computed value (a URI) of one or more of an element's
    * filter/mask/clip/etc CSS properties changes, causing the element's frame
    * to start/stop referencing (or reference different) SVG resource elements.
    * (_Not_ used to handle changes to referenced resource elements.) Using this
    * hint results in nsSVGEffects::UpdateEffects being called on the element's
    * frame.
    */
   nsChangeHint_UpdateEffects = 0x80,
   /**
    * Visual change only, but the change can be handled entirely by
    * updating the layer(s) for the frame.
    * Updates all descendants (including following placeholders to out-of-flows).
    */
   nsChangeHint_UpdateOpacityLayer = 0x100,
   /**
    * Updates all descendants. Any placeholder descendants' out-of-flows
    * are also descendants of the transformed frame, so they're updated.
    */
   nsChangeHint_UpdateTransformLayer = 0x200,
   /**
    * Change requires frame change (e.g., display:).
    * This subsumes all the above. Reconstructs all frame descendants,
    * including following placeholders to out-of-flows.
    */
   nsChangeHint_ReconstructFrame = 0x400,
   /**
    * The frame's overflow area has changed, either through a change in its
    * transform or a change in its position. Does not update any descendant
    * frames.
    */
   nsChangeHint_UpdateOverflow = 0x800,
   /**
    * The frame's overflow area has changed, through a change in its transform.
    * Does not update any descendant frames.
    */
   nsChangeHint_UpdatePostTransformOverflow = 0x1000,
   /**
    * The children-only transform of an SVG frame changed, requiring the
    * overflow rects of the frame's immediate children to be updated.
    */
   nsChangeHint_ChildrenOnlyTransform = 0x2000,
   /**
    * The frame's offsets have changed, while its dimensions might have
    * changed as well.  This hint is used for positioned frames if their
    * offset changes.  If we decide that the dimensions are likely to
    * change, this will trigger a reflow.
    *
    * Note that this should probably be used in combination with
    * nsChangeHint_UpdateOverflow in order to get the overflow areas of
    * the ancestors updated as well.
    */
   nsChangeHint_RecomputePosition = 0x4000,
   /**
    * Behaves like ReconstructFrame, but only if the frame has descendants
    * that are absolutely or fixed position. Use this hint when a style change
    * has changed whether the frame is a container for fixed-pos or abs-pos
    * elements, but reframing is otherwise not needed.
    */
   nsChangeHint_AddOrRemoveTransform = 0x8000,
   /**
    * This change hint has *no* change handling behavior.  However, it
    * exists to be a non-inherited hint, because when the border-style
    * changes, and it's inherited by a child, that might require a reflow
    * due to the border-width change on the child.
    */
   nsChangeHint_BorderStyleNoneChange = 0x10000,
   /**
    * SVG textPath needs to be recomputed because the path has changed.
    * This means that the glyph positions of the text need to be recomputed.
    */
   nsChangeHint_UpdateTextPath = 0x20000
   // IMPORTANT NOTE: When adding new hints, consider whether you need to
   // add them to NS_HintsNotHandledForDescendantsIn() below.
 };
 // Redefine these operators to return nothing. This will catch any use
 // of these operators on hints. We should not be using these operators
 // on nsChangeHints
 inline void operator<(nsChangeHint s1, nsChangeHint s2) {}
 inline void operator>(nsChangeHint s1, nsChangeHint s2) {}
 inline void operator!=(nsChangeHint s1, nsChangeHint s2) {}
 inline void operator==(nsChangeHint s1, nsChangeHint s2) {}
 inline void operator<=(nsChangeHint s1, nsChangeHint s2) {}
 inline void operator>=(nsChangeHint s1, nsChangeHint s2) {}
 // Operators on nsChangeHints
 // Merge two hints, taking the union
 inline nsChangeHint NS_CombineHint(nsChangeHint aH1, nsChangeHint aH2) {
   return (nsChangeHint)(aH1 | aH2);
 }
 // Merge two hints, taking the union
 inline nsChangeHint NS_SubtractHint(nsChangeHint aH1, nsChangeHint aH2) {
   return (nsChangeHint)(aH1 & ~aH2);
 }
 // Merge the "src" hint into the "dst" hint
 // Returns true iff the destination changed
 inline bool NS_UpdateHint(nsChangeHint& aDest, nsChangeHint aSrc) {
   nsChangeHint r = (nsChangeHint)(aDest | aSrc);
   bool changed = (int)r != (int)aDest;
   aDest = r;
   return changed;
 }
 // Returns true iff the second hint contains all the hints of the first hint
 inline bool NS_IsHintSubset(nsChangeHint aSubset, nsChangeHint aSuperSet) {
   return (aSubset & aSuperSet) == aSubset;
 }
 /**
  * We have an optimization when processing change hints which prevents
  * us from visiting the descendants of a node when a hint on that node
  * is being processed.  This optimization does not apply in some of the
  * cases where applying a hint to an element does not necessarily result
  * in the same hint being handled on the descendants.
  */
 // The most hints that NS_HintsNotHandledForDescendantsIn could possibly return:
 #define nsChangeHint_Hints_NotHandledForDescendants nsChangeHint( \
           nsChangeHint_UpdateTransformLayer | \
           nsChangeHint_UpdateEffects | \
           nsChangeHint_UpdateOpacityLayer | \
           nsChangeHint_UpdateOverflow | \
           nsChangeHint_UpdatePostTransformOverflow | \
           nsChangeHint_ChildrenOnlyTransform | \
           nsChangeHint_RecomputePosition | \
           nsChangeHint_AddOrRemoveTransform | \
           nsChangeHint_BorderStyleNoneChange | \
           nsChangeHint_NeedReflow | \
           nsChangeHint_ClearAncestorIntrinsics)
 inline nsChangeHint NS_HintsNotHandledForDescendantsIn(nsChangeHint aChangeHint) {
   nsChangeHint result = nsChangeHint(aChangeHint & (
     nsChangeHint_UpdateTransformLayer |
     nsChangeHint_UpdateEffects |
     nsChangeHint_UpdateOpacityLayer |
     nsChangeHint_UpdateOverflow |
     nsChangeHint_UpdatePostTransformOverflow |
     nsChangeHint_ChildrenOnlyTransform |
     nsChangeHint_RecomputePosition |
     nsChangeHint_AddOrRemoveTransform |
     nsChangeHint_BorderStyleNoneChange));
   if (!NS_IsHintSubset(nsChangeHint_NeedDirtyReflow, aChangeHint) &&
       NS_IsHintSubset(nsChangeHint_NeedReflow, aChangeHint)) {
     // If NeedDirtyReflow is *not* set, then NeedReflow is a
     // non-inherited hint.
     NS_UpdateHint(result, nsChangeHint_NeedReflow);
   }
   if (!NS_IsHintSubset(nsChangeHint_ClearDescendantIntrinsics, aChangeHint) &&
       NS_IsHintSubset(nsChangeHint_ClearAncestorIntrinsics, aChangeHint)) {
     // If ClearDescendantIntrinsics is *not* set, then
     // ClearAncestorIntrinsics is a non-inherited hint.
     NS_UpdateHint(result, nsChangeHint_ClearAncestorIntrinsics);
   }
   NS_ABORT_IF_FALSE(NS_IsHintSubset(result,
                                     nsChangeHint_Hints_NotHandledForDescendants),
                     "something is inconsistent");
   return result;
 }
 // Redefine the old NS_STYLE_HINT constants in terms of the new hint structure
 #define NS_STYLE_HINT_NONE \
   nsChangeHint(0)
 #define NS_STYLE_HINT_VISUAL \
   nsChangeHint(nsChangeHint_RepaintFrame | nsChangeHint_SyncFrameView)
 #define nsChangeHint_AllReflowHints                     \
   nsChangeHint(nsChangeHint_NeedReflow |                \
                nsChangeHint_ClearAncestorIntrinsics |   \
                nsChangeHint_ClearDescendantIntrinsics | \
                nsChangeHint_NeedDirtyReflow)
 #define NS_STYLE_HINT_REFLOW \
   nsChangeHint(NS_STYLE_HINT_VISUAL | nsChangeHint_AllReflowHints)
 #define NS_STYLE_HINT_FRAMECHANGE \
   nsChangeHint(NS_STYLE_HINT_REFLOW | nsChangeHint_ReconstructFrame)
 /**
  * |nsRestyleHint| is a bitfield for the result of
  * |HasStateDependentStyle| and |HasAttributeDependentStyle|.  When no
  * restyling is necessary, use |nsRestyleHint(0)|.
  */
 enum nsRestyleHint {
   eRestyle_Self = 0x1,
   eRestyle_Subtree = 0x2, /* self and descendants */
   eRestyle_LaterSiblings = 0x4 /* implies "and descendants" */
 };
 #endif /* nsChangeHint_h___ */

The Tor Browser / annotate

layout/base/nsChangeHint.h@b8a032363ba2 (annotated)

layout/base/nsChangeHint.h