Hi, I'm bumping into an issue with Okio's `BufferedSource.select()` and `TypedOptions`. It seems lik...

# squarelibraries

[Adam S]

Hi, I'm bumping into an issue with Okio's BufferedSource.select() and TypedOptions. It seems like the options selects the shortest match,. E.g. when a source starts with fffe0000 it will always select the fffe option, but I want it to select fffe0000.

I can implement something manually, but I wanted to check first: is this the intended behaviour?

demo.kt.cpp

[jw]

Probably? Usually we have a terminating discriminator that disambiguates prefixes of other items, such as in JSON we would select lunch" and lunchbox" allowing the closing quote to force the prefix to otherwise no longer be a prefix.

[jw]

You can file an issue about it. I'm not sure whether it's something we can change or not. It might require new API surface.

[jessewilson]

Sort your options by the order you’d prefer the match to be in

[jessewilson]

Like so:

private val UnicodeBomOptions: TypedOptions<CharEncoding> =
  TypedOptions.of(CharEncoding.entries.sortedBy { it.bom }.reversed()) {
    when (it) {
      CharEncoding.UTF_8 -> it.bom
      CharEncoding.UTF_16BE -> it.bom
      CharEncoding.UTF_16LE -> it.bom
      CharEncoding.UTF_32BE -> it.bom
      CharEncoding.UTF_32LE -> it.bom
    }
  }

[jessewilson]

...reverse sorting will be prefer-longest; forward sorting will be prefer-shortest

[jw]

but also... UTF-32LE is ffff0000, no?

https://github.com/square/okhttp/blob/master/okhttp/src/main/kotlin/okhttp3/internal/-UtilCommon.kt#L51-L64

[jw]

wow seems like no https://en.wikipedia.org/wiki/Byte_order_mark#Byte-order_marks_by_encoding

[jw]

fffffffuuuuuuu https://github.com/square/okhttp/pull/2823/files#diff-f759439796e5b47ee6700f4e80868205dc5ca03974b9d9b5ec6c9c4ec0f23480R53

[jw]

good thing no one uses that massively wasteful encoding

[jessewilson]

whoa

[jessewilson]

that’s embarrassing

[jw]

be is wrong too

[jw]

wtf was i smoking

[jessewilson]

BE is right? FE FF

[jw]

the utf-32 one is wrong

[jessewilson]

oh, yep

[jessewilson]

0xFFFFuuuu

[jw]

need laugh/cry/sob emoji here

[Adam S]

Sort your options by the order you’d prefer the match to be in

Ahhhh right, sort the enum entries! That works, thanks!

[Adam S]

It looks like there might be a few other places with the wrong BOM?

https://github.com/search?q=org%3Asquare+ffff0000+language%3AKotlin&type=code

[Adam S]

quick PRs (made in the web-gui - I might have missed something)

• https://github.com/square/wire/pull/2935
• https://github.com/square/okhttp/pull/8403

[jw]

The order needs to change per the above discussion