On Sat, 31 Jul 2021 14:39:02 GMT, Markus KARG <github.com+1701815+mk...@openjdk.org> wrote:
>>> Just on naming, the existing channel implementations use "dst" for the >>> destination and "wbc" (not "oc") for writable byte channels. Just >>> mentioning it so that the new code can be kept consistent where possible. >> >> I have renamed `dest` to `dst` and `oc` to `wbc` in >> https://github.com/openjdk/jdk/pull/4263/commits/f91d5422c41e25410a81aad54a45b2d0e171305a. > >> Is this loop correct for the case that the channel gets truncated? In that >> case transferTo will return 0 as no bytes will be transferred and I'm >> concerned this code will go into an infinite loop. > > Good catch, indeed missed this particular situation! > > The modified code found in > https://github.com/openjdk/jdk/pull/4263/commits/4b501b205c6f1c48bbc82d7a154aed3fc41b1a20 > should be safe from infinite loops, as it checks the actual file length in > each iteration (even if this costs us one more `synchronized` per iteration). > > This will also improve the situation with concurrent *extension* of the file > as outlined in: > >>If src is extended at an inconvenient point in time, for example between the >>return from a call to src.transferTo() that makes bytesWritten < n false and >>the evaluation of that terminating condition, then it appears that not all >>the content of src will be transferred to dest. I am not however sure that >>this violates any contract but it could be a behavioral change from the >>existing implementation. > > As `size()` is called in each iteration, it will pick up the appendend bytes. > Still the situation exists that some bytes are *replaced* in the source file > -- but that is actually out-of-scope of this PR...! ;-) > Also can you can check that IllegalBlockingModeException is thrown for the > case ch is a SelectableChannel configured non-blocking and the destination is > a FileChannel? Done in https://github.com/openjdk/jdk/pull/4263/commits/8e2889fd6138d8aa8e308a1cd2aea3546a7c43a7, but honestly I'd kindly like to ask for a brief explanation why this has to be done. What actual bad effect would happen if I do not throw? ------------- PR: https://git.openjdk.java.net/jdk/pull/4263
