[PATCH] D51481: [clangd] Implement proximity path boosting for Dex

[Eric Liu via Phabricator via cfe-commits]

ioeric added inline comments.


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Comment at: clang-tools-extra/clangd/index/dex/DexIndex.h:45
+  void build(std::shared_ptr<std::vector<const Symbol *>> Symbols,
+             llvm::ArrayRef<std::string> URISchemes);
 
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sammccall wrote:
> ioeric wrote:
> > URI schemes are property of `Symbols`. We shouldn't need to pass specify the schemes again. Dex can collect all possible URI schemes when building the index.
> > 
> > I think we could generate proximity paths for index symbols without knowing about schemes (when building the index). For example, we could `canonicalize` the URI (as in `FileDistance.cpp`), for example, by converting `test:///x/y/z` to `/test:/x/y/z`.  For a query, we would first convert query proximity paths to URIs (of all possible schemes), perform the same canonicalization on URIs, and then use the canonicalized paths to compute proximity.
> We had an offline discussion about URIs which might be interesting.
> 
> Fetching posting lists for all URI schemes at query time seems wasteful, @ilya-biryukov pointed out that in practice each file is going to exist in some preferred URI space, and we should only compare that one.
> The only obstacle to doing that is that the preference order for URI schemes is not global, each place we need it it's accepted as configuration.
> 
> Maybe we should change that: as part of registering the URI schemes, we define a preferred order. And instead of the current operation `makeURI(File, scheme)` we should just offer APIs like `makePreferredURI(File)` and `makeFileURI(File)`.
That sounds like a good idea. 

We just need to be careful that indexes do not use non-preferred schemes (e.g. standalone indexer doesn't have the preferred scheme registered). This shouldn't be a problem in practice though.


https://reviews.llvm.org/D51481