wasi: nonblocking pipes on Windows #1570
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Improve tetratelabs#1500 with a simple observation, i.e. we really need non-blocking I/O only for pipes and sockets. Now, for sockets we can use WinSock select, as for pipes, select_windows.go already imports PeekNamedPipe. We combine PeekNamedPipe with a blocking Read only for those cases when PeekNamedPipe returns n > 0, which means a Read of n bytes won't block. We special case n == 0 to return EAGAIN and ERROR_BROKEN_PIPE as a non-failure (EOF reached). We also introduce `isNonblock(f)` function, specialized on Windows to also check if the file is ModeNamedPipe; otherwise we would default to blocking anyway. Signed-off-by: Edoardo Vacchi <evacchi@users.noreply.github.com>
ncruces
approved these changes
Jul 9, 2023
codefromthecrypt
approved these changes
Jul 9, 2023
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Improve #1500 with a simple observation, i.e. we really need non-blocking I/O only for pipes and sockets.
Now, for sockets we can use WinSock select, as for pipes, select_windows.go already imports PeekNamedPipe.
We combine PeekNamedPipe with a blocking Read only for those cases when PeekNamedPipe returns n > 0, which means a Read of n bytes won't block.
We special case n == 0 to return EAGAIN and
ERROR_BROKEN_PIPE as a non-failure (EOF reached).
We also introduce
isNonblock(f)function, specialized on Windows to also check if the file is ModeNamedPipe; otherwise we would default to blocking anyway.