> I uncovered a problem that has been in the CSS engine for a long time, even > before #1076 was applied. However, #1076 made this problem more obvious > because of a side fix that was done there: > > - The `BitSet` `equals` implementation was updated to NOT take the length of > the allocated array (to store the bits in) into account for equality. As this > array is just allocated on demand depending on what bits were set and reset, > it should not be taken into account for equality > > The above bug hid problems when nodes were **supposed to** share a CSS cache > entry, but didn't because their `BitSet`s were considered different (even > though semantically, they were the same). > > With the fix in #1076, a lot more cases were sharing CSS cache entries (as > they should) but this now exposed a bug in how `CssStyleHelper` handled the > absence of a cached property. Basically, absence could mean two things before > this change: > > - The property was not computed at all: it either didn't exist at the time > (due to `CssMetaData` changing!) or because the property was not settable > (because it was bound) > - The property was computed but no styles applied to it, so no need to cache > anything... > > The CSS engine always assumed the latter, which means that if for whatever > reason the cache entry was created by a Node that had outdated `CssMetaData` > (a Control that is yet to be skinned, or one where a CSS property was > unsettable), the engine would assume that such a missing property was > unstyled and can safely be reset. As entries are shared, this doesn't hold > true for all nodes that share the same entry (if another node that shares the > same entry has different `CssMetaData` or did not have the same property > bound, then it may have been styled, and should not be reset!). > > ## Tests that confirm the problem > > I added 4 new test cases, for four paths that could potentially result in the > wrong things being in the cache: > > - A cache entry being created for a Node that has bound properties (and is > later shared with a different node) > - A cache entry being created for a Node that isn't skinned yet (and so it's > CssMetaData may change); the CSS engine simply can never assume that > CssMetaData is stable (skins can also be changed at any time) > - Ensuring that an exception during `applyStyle` still results in a `SKIP` > entry in the cache > - Ensuring that we still put a value in the cache, even if the Node can't use > it itself directly as its value is bound (this test overlaps a bit with the > first, perhaps one can be remo...
John Hendrikx has updated the pull request incrementally with one additional commit since the last revision: Update javadoc ------------- Changes: - all: https://git.openjdk.org/jfx/pull/2218/files - new: https://git.openjdk.org/jfx/pull/2218/files/5dcd54c1..905bda30 Webrevs: - full: https://webrevs.openjdk.org/?repo=jfx&pr=2218&range=03 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=2218&range=02-03 Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod Patch: https://git.openjdk.org/jfx/pull/2218.diff Fetch: git fetch https://git.openjdk.org/jfx.git pull/2218/head:pull/2218 PR: https://git.openjdk.org/jfx/pull/2218
