[clangd] NFC: Document URIDistance

[kbobyrev]

Summary

URIDistance constructor should mention that Sources must contain *absolute paths*, not URIs. This is not very clear when looking at the interface, especially given that distance(...) accepts URI, not an absolute path which can give the wrong impression.

[sammccall]

clang-tools-extra/clangd/FileDistance.h

66 ↗

(On Diff #164066)

memoizes is correct here
https://en.wikipedia.org/wiki/Memoization

89 ↗

(On Diff #164066)

The constructor doesn't do any computation, thus there's nothing to memoize.

I'd suggest dropping the second sentence here, that's the only noteworthy thing specific to this constructor.

[kbobyrev]

clang-tools-extra/clangd/FileDistance.h

89 ↗

(On Diff #164066)

Sorry, did you mean dropping the *first sentence* here? The second one seems to be the one you describe.

clangd/FileDistance.h

private:
   FileDistanceOptions Opts;
 };
 
 // Supports lookups like FileDistance, but the lookup keys are URIs.
 // We convert each of the sources to the scheme of the URI and do a FileDistance
 // comparison on the bodies.
 class URIDistance {
 public:
+  // \p Sources must contain absolute paths, not URIs.
   URIDistance(llvm::StringMap<SourceParams> Sources,
               const FileDistanceOptions &Opts = {})
       : Sources(Sources), Opts(Opts) {}
 
   // Computes the minimum distance from any source to the URI.
   // Only sources that can be mapped into the URI's scheme are considered.
   unsigned distance(llvm::StringRef URI);