I was wondering why this never made it to the list - seems I just sent
it to Michal... So here's what I sent...
John
On 05/16/2017 05:34 PM, John Ferlan wrote:
>
>
> On 05/16/2017 10:03 AM, Michal Privoznik wrote:
>> This is just a wrapper over new functions that have been just
>> introduced: virStreamRecvFlags(), virStreamRecvHole(). It's very
>> similar to virStreamRecvAll() except it handles sparse streams
>> well.
>>
>> Signed-off-by: Michal Privoznik <mprivozn@xxxxxxxxxx>
>> ---
>> include/libvirt/libvirt-stream.h | 33 ++++++++++-
>> src/libvirt-stream.c | 123 +++++++++++++++++++++++++++++++++++++++
>> src/libvirt_public.syms | 1 +
>> 3 files changed, 154 insertions(+), 3 deletions(-)
>>
>
> [...]
>
>> diff --git a/src/libvirt-stream.c b/src/libvirt-stream.c
>> index bedb6159a..6bf4c4f29 100644
>> --- a/src/libvirt-stream.c
>> +++ b/src/libvirt-stream.c
>> @@ -668,6 +668,129 @@ virStreamRecvAll(virStreamPtr stream,
>> }
>>
>>
>> +/**
>> + * virStreamSparseRecvAll:
>> + * @stream: pointer to the stream object
>> + * @handler: sink callback for writing data to application
>> + * @holeHandler: stream hole callback for skipping holes
>> + * @opaque: application defined data
>> + *
>> + * Receive the entire data stream, sending the data to the
>> + * requested data sink @handler and calling the skip @holeHandler
>> + * to generate holes for sparse stream targets. This is simply a
>> + * convenient alternative to virStreamRecvFlags, for apps that do
>> + * blocking-I/O.
>> + *
>> + * An example using this with a hypothetical file download
>> + * API looks like:
>> + *
>> + * int mysink(virStreamPtr st, const char *buf, int nbytes, void *opaque) {
>> + * int *fd = opaque;
>> + *
>> + * return write(*fd, buf, nbytes);
>> + * }
>> + *
>> + * int myskip(virStreamPtr st, long long offset, void *opaque) {
>> + * int *fd = opaque;
>> + *
>
> I think this is where perhaps the example of lseek in "off_t" chunks of
> "long long offset" would be applicable... Perhaps why I ended up in the
> off_t rathole before.
>
>> + * return lseek(*fd, offset, SEEK_CUR) == (off_t) -1 ? -1 : 0;
>> + * }
>> + *
>> + * virStreamPtr st = virStreamNew(conn, 0);
>> + * int fd = open("demo.iso", O_WRONLY);
>> + *
>> + * virConnectDownloadSparseFile(conn, st);
>
> ^^ This API doesn't exist... Of course neither did
> virConnectDownloadFile from whence you copied the example. Maybe both
> should be 'adjusted'.
>
>
> Reviewed-by: John Ferlan <jferlan@xxxxxxxxxx>
>
> John
>
>> + * if (virStreamSparseRecvAll(st, mysink, myskip, &fd) < 0) {
>> + * ...report an error ...
>> + * goto done;
>> + * }
>> + * if (virStreamFinish(st) < 0)
>> + * ...report an error...
>> + * virStreamFree(st);
>> + * close(fd);
>> + *
>> + * Note that @opaque data is shared between both @handler and
>> + * @holeHandler callbacks.
>> + *
>> + * Returns 0 if all the data was successfully received. The caller
>> + * should invoke virStreamFinish(st) to flush the stream upon
>> + * success and then virStreamFree(st).
>> + *
>> + * Returns -1 upon any error, with virStreamAbort() already
>> + * having been called, so the caller need only call virStreamFree().
>> + */
>
>
> [...]
>
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