[ruby-core:56196] Re: [Ruby 1.9 - Bug #5138][Open] Add nonblocking IO that does not use exceptions for EOF and EWOULDBLOCK

On Tue, Aug 02, 2011 at 07:35:15AM +0900, Yehuda Katz wrote:
> 
> Issue #5138 has been reported by Yehuda Katz.
> 
> ----------------------------------------
> Bug #5138: Add nonblocking IO that does not use exceptions for EOF and EWOULDBLOCK
> http://redmine.ruby-lang.org/issues/5138
> 
> Author: Yehuda Katz
> Status: Open
> Priority: Normal
> Assignee: Yukihiro Matsumoto
> Category: core
> Target version: 1.9.4
> ruby -v: ruby 1.9.4dev (2011-07-31 trunk 32788) [x86_64-darwin11.0.0]
> 
> 
> The current Ruby I/O classes have non-blocking methods (read_nonblock and write_nonblock). These methods will never block, and if they would block, they raise an exception instead (IO::WaitReadable or IO::WaitWritable). In addition, if the IO is at EOF, they raise an EOFError.
> 
> These exceptions are raised repeatedly in virtually every use of the non-blocking methods. This patch adds a pair of methods (try_read_nonblock and try_write_nonblock) that have the same semantics as the existing methods, but they return Symbols instead of raising exceptions for these routine cases:
> 
> * :read_would_block
> * :write_would_block
> * :eof
> 
> The patch contains updates for IO, StringIO, and OpenSSL. The updates are fully documented and tested.

In the last developer meeting, matz suggested that the existing
nonblocking IO functions take an extra option to specify whether or not
exceptions should be raised.

https://bugs.ruby-lang.org/projects/ruby/wiki/DevelopersMeeting20130712#Non-blocking-reads-without-exceptions-Feature-5138

Something like this:

    chunk = @io.read_nonblock(BUFSIZE, exception: false)

I am happy with a solution like this.

-- 
Aaron Patterson
http://tenderlovemaking.com/