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Guillaume Gomez
fc7ca70013
rustdoc: use a trie for name-based search Potentially https://github.com/rust-lang/rust/issues/131156 — need to try reproducing the problem with `windows` Preview and profiler results ---------------------------- Here's some quick profiling in Firefox done on the rust compiler docs: - Before: https://share.firefox.dev/3UPm3M8 - After: https://share.firefox.dev/40LXvYb Here's the results for the node.js profiler: - https://notriddle.com/rustdoc-html-demo-15/trie-perf/index.html Here's a copy that you can use to try it out. Compare it with [the nightly]. Try typing `typecheckercontext` one character at a time, slowly. - https://notriddle.com/rustdoc-html-demo-15/compiler-doc-trie/index.html [the nightly]: https://doc.rust-lang.org/nightly/nightly-rustc/ The fuzzy match algo is based on [Fast String Correction with Levenshtein-Automata] and the corresponding implementation code in [moman] and [Lucene]; the bit-packing representation comes from Lucene, but the actual matcher is more based on `fsc.py`. As suggested in the paper, a trie is used to represent the FSA dictionary. The same trie is used for prefix matching. Substring matching is done with a side table of three-character[^1] windows that point into the trie. [Fast String Correction with Levenshtein-Automata]: https://github.com/tpn/pdfs/blob/master/Fast%20String%20Correction%20with%20Levenshtein-Automata%20(2002)%20(10.1.1.16.652).pdf [Lucene]: https://fossies.org/linux/lucene/lucene/core/src/java/org/apache/lucene/util/automaton/Lev1TParametricDescription.java [moman]: https://gitlab.com/notriddle/moman-rustdoc User-visible changes -------------------- I don't expect anybody to notice anything, but it does cause two changes: - Substring matches, in the middle of a name, only apply if there's three or more characters in the search query. - Levenshtein distance limit now maxes out at two. In the old version, the limit was w/3, so you could get looser matches for queries with 9 or more characters[^1] in them. - It uses more RAM. - It's faster (assuming you don't swap thrash). [^1]: technically utf-16 code units