[htoolkit-users] HSQL patch: collectRowsAsync

[Frederik E. <fre...@a5...>]

(needed a better subject)

On Tue, Feb 22, 2005 at 03:38:55AM -0800, Frederik Eaton wrote:
> Please apply:
> 
> --- HSQL/src/HSQL.hsc   2005-02-22 03:37:23.000000000 -0800
> +++ HSQL-modified/src/HSQL.hsc  2005-02-22 03:36:44.000000000 -0800
> @@ -606,3 +606,22 @@
>                                         return (x:xs)
>                                 else return []
>  
> +-- | The 'collectRowsASync' function is just like collectRows, but it
> +-- uses unsafeInterleaveIO to in the same manner as hGetContents to
> +-- cause rows to be read asynchronously from the database in an
> +-- "on-demand" fashion as list elements are accessed in the result.
> +collectRowsAsync :: (Statement -> IO a) -> Statement -> IO [a]
> +collectRowsAsync act stmt = loop
> +      where
> +        closeAndThrow e = do closeStatement stmt; throw e
> +        loop = unsafeInterleaveIO $ (do
> +         success <- catch (fetch stmt) closeAndThrow
> +         if success
> +            then do
> +              x <- catch (act stmt) closeAndThrow
> +              xs <- loop
> +              return (x:xs)
> +            else do
> +              closeStatement stmt
> +              return [])
> +
> 
> Thanks,
> 
>   Frederik
> 
> -- 
> Frederik Eaton                         http://ofb.net/~frederik/
> 

-- 
Frederik Eaton                         http://ofb.net/~frederik/