Integrate utf8 hPutStr to standard hPutStr #589

BebeSparkelSparkel · 2024-04-28T17:03:20Z

Data.Text.IO.Utf8.hPutStr was implemented in #503 and has much better performance than Data.Text.IO.hPutStr when the encoding is "UTF-8" and the neline is LF, so I added it.

Question: Is there a faster way to check for the encoding without checking for string equality?

Lysxia

Inspecting the textEncodingName of TextEncoding like you did seems like the right way.

src/Data/Text/IO.hs

… hPutStr

Lysxia · 2024-06-03T15:30:37Z

I merged with master (adapting to changes from #600 which moved the logic of hPutStr to Data.Text.Internal.IO.hPutStream) (this PR is squashable, just not rebaseable) and added a comment about why the pointer-equality is fine (I initially thought it had to be guarded as enc `unsafePtrEquality` utf8 || enc == utf8 but convinced myself otherwise).

Bodigrim · 2024-06-03T19:39:35Z

@Lysxia shall we drop GHC 8.2 CI job?

Bodigrim · 2024-06-03T22:19:33Z

src/Data/Text/Internal/IO.hs

+-- | Write a string to a handle, followed by a newline.
+hPutStrLn :: Handle -> Text -> IO ()
+hPutStrLn h t = hPutStreamOrUtf8 h (streamLn t) (Just putUtf8)
+  where putUtf8 = hPutBuilder h (encodeUtf8Builder t <> charUtf8 '\n')


Why not B.hPutStrLn h (encodeUtf8 t)?

It would have to be B.hPutStrLn h (encodeUtf8 (t <> '\n')). I couldn't find another way to append the '\n' at the end in constant time. Open to suggestions.

I'd expect B.hPutStrLn to append '\n' on its own, am I missing something?

Oh I didn't see your Ln. There is no B.hPutStrLn... right?

hPutStrLn :: Handle -> ByteString -> IO () hPutStrLn h ps = hPut h ps >> hPut h (L.singleton 0x0a)

https://github.com/haskell/bytestring/blob/46a3aeb179c26d2385f95ba518eaa5464c94ceaa/Data/ByteString/Lazy/Char8.hs#L932

I do not like the B.hPutStrLn implementation since it breaks the atomic printing that was just implemented for strict hPustStrLn in #600

I'd say that non-100%-atomicity of B.hPutStrLn is for bytestring to resolve, not for us. But does hPutBuilder guarantee atomic printing?

B.hPutBuilder does if it can fit in the buffer.

I reopened haskell/bytestring#200 and added a comment.

Bodigrim · 2024-06-22T23:08:43Z

Thanks a ton!

Lysxia reviewed Apr 30, 2024

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