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authorjanekptacijarabaci <janekptacijarabaci@seznam.cz>2018-04-24 21:39:13 +0200
committerjanekptacijarabaci <janekptacijarabaci@seznam.cz>2018-04-24 21:39:13 +0200
commiteae8d21428acdb3fb842df091ded0eb276bcaaaa (patch)
tree8fcdb943e19ec1ca33bec3b39636311dcddd38f0 /dom/base/nsDocument.cpp
parentd0e748cadabba2b7cbf7407c4bca665315bf00fe (diff)
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moebius#138: Optimize operations on root of deeply-nested frame tree
https://github.com/MoonchildProductions/moebius/pull/138
Diffstat (limited to 'dom/base/nsDocument.cpp')
-rw-r--r--dom/base/nsDocument.cpp21
1 files changed, 19 insertions, 2 deletions
diff --git a/dom/base/nsDocument.cpp b/dom/base/nsDocument.cpp
index d5954a62c..fd3b52948 100644
--- a/dom/base/nsDocument.cpp
+++ b/dom/base/nsDocument.cpp
@@ -2054,10 +2054,17 @@ nsDocument::ResetToURI(nsIURI *aURI, nsILoadGroup *aLoadGroup,
mFirstChild = content->GetNextSibling();
}
mChildren.RemoveChildAt(i);
+ if (content == mCachedRootElement) {
+ // Immediately clear mCachedRootElement, now that it's been removed
+ // from mChildren, so that GetRootElement() will stop returning this
+ // now-stale value.
+ mCachedRootElement = nullptr;
+ }
nsNodeUtils::ContentRemoved(this, content, i, previousSibling);
content->UnbindFromTree();
}
- mCachedRootElement = nullptr;
+ MOZ_ASSERT(!mCachedRootElement,
+ "After removing all children, there should be no root elem");
}
mInUnlinkOrDeletion = oldVal;
@@ -3913,8 +3920,18 @@ nsDocument::RemoveChildAt(uint32_t aIndex, bool aNotify)
DestroyElementMaps();
}
- doRemoveChildAt(aIndex, aNotify, oldKid, mChildren);
+ // Preemptively clear mCachedRootElement, since we may be about to remove it
+ // from our child list, and we don't want to return this maybe-obsolete value
+ // from any GetRootElement() calls that happen inside of doRemoveChildAt().
+ // (NOTE: for this to be useful, doRemoveChildAt() must NOT trigger any
+ // GetRootElement() calls until after it's removed the child from mChildren.
+ // Any call before that point would restore this soon-to-be-obsolete cached
+ // answer, and our clearing here would be fruitless.)
mCachedRootElement = nullptr;
+ doRemoveChildAt(aIndex, aNotify, oldKid, mChildren);
+ MOZ_ASSERT(mCachedRootElement != oldKid,
+ "Stale pointer in mCachedRootElement, after we tried to clear it "
+ "(maybe somebody called GetRootElement() too early?)");
}
void