Re: [PATCH] stream_to_pack: xread does not guarantee to read all requested bytes

Antoine Pelisse [off-list ref] writes:

I was actually wondering when it's better to use xread() over
read_in_full()?

When the caller wants to do more control over a read that may have
to loop.  For example, this loop in builtin/index-pack.c::fill()

	do {
		ssize_t ret = xread(input_fd, input_buffer + input_len,
				sizeof(input_buffer) - input_len);
		if (ret <= 0) {
			if (!ret)
				die(_("early EOF"));
			die_errno(_("read error on input"));
		}
		input_len += ret;
		if (from_stdin)
			display_throughput(progress, consumed_bytes + input_len);
	} while (input_len < min);

cannot be replaced blindly with read_in_full() because (1) the
caller wants to do the "display_throughput()" part in the loop, and
(2) the caller wants to fill at least "min" bytes but can happily
accept to read more up to the size of the input_buffer.