Avoid a second tree lookup in Workspace.getResourceInfo - #2883
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getResourceInfo walked the element tree twice for every read access: once through ElementTree.includes and again through ElementTree.getElementData. The single-slot lookupCache that is meant to make the second walk free compares keys by identity and is shared by all threads, so under concurrent access (builders, indexers) it gets replaced between the two calls and the second walk runs for real. Add the internal ElementTree.getElementDataOrNull, which does one lookup and returns null when the element is absent, and use it for the non-mutable path. This removes one full tree walk plus one monitor acquisition from the hottest resource access path. Behavior is unchanged: a missing element and an element with null data both already resulted in null.
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Workspace.getResourceInfois one of the hottest paths in the resources plug-in, and it walked the element tree twice for every read: once throughElementTree.includesand once more throughElementTree.getElementData. The single-slotlookupCachethat is supposed to make the second walk free compares keys by identity and is shared by all threads, so with builders and indexers hitting the sameElementTreeit gets replaced between the two calls and the second walk runs for real.This adds the internal
ElementTree.getElementDataOrNull, which performs one lookup and returnsnullwhen the element is absent, and uses it for the non-mutable case. That removes a full tree walk plus one monitor acquisition per call. Behavior is unchanged: an absent element and an element withnulldata both already producednull.org.eclipse.core.internal.watsonis internal, so there is no API impact.