RFR: 8271308: (fc) FileChannel.transferTo() transfers no more than Integer.MAX_VALUE bytes in one call

[Brian Burkhalter]

On Thu, 29 Jul 2021 23:08:58 GMT, Brian Burkhalter <bpb at openjdk.org> wrote:

> Please consider this request to enhance `java.nio.channels.FileChannel.transferTo()` to be able to transfer more than `Integer.MAX_VALUE` bytes in one call.

The approach taken avoids adding loops inside the various private `transferToX()` methods. Without this change the new test fails. No existing tests fail because of the change.

The native method `maxTransferSize0()` might be better replaced by a constant

    private static final long MAX_TRANSFER_SIZE = (long)Integer.MAX_VALUE - 1;

This would guarantee that Windows’ `TransmitFile()` would not reject a transfer as being too large (`count == Integer.MAX_VALUE`) thereby forcing a slower path and would little affect the other platforms.

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PR: https://git.openjdk.java.net/jdk/pull/4940