Re: [libvirt] [PATCH v2 13/38] Introduce VIR_STREAM_RECV_STOP_AT_HOLE flag

This flag is for virStreamRecvFlags API. Its purpose is to stop reading from the stream if a hole occurred as holes are to be threated separately.

Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com&gt; --- include/libvirt/libvirt-stream.h | 4 ++++ src/libvirt-stream.c | 30 +++++++++++++++++++++++++++++- 2 files changed, 33 insertions(+), 1 deletion(-) diff --git a/include/libvirt/libvirt-stream.h b/include/libvirt/libvirt-stream.h index 2ebda74..23fcc26 100644 --- a/include/libvirt/libvirt-stream.h +++ b/include/libvirt/libvirt-stream.h @@ -45,6 +45,10 @@ int virStreamRecv(virStreamPtr st, char *data, size_t nbytes); +typedef enum { + VIR_STREAM_RECV_STOP_AT_HOLE = (1 << 0), +} virStreamRecvFlagsValues; + int virStreamRecvFlags(virStreamPtr st, char *data, size_t nbytes, diff --git a/src/libvirt-stream.c b/src/libvirt-stream.c index 3ac9e0d..1162d33 100644 --- a/src/libvirt-stream.c +++ b/src/libvirt-stream.c @@ -290,7 +290,7 @@ virStreamRecv(virStreamPtr stream, * @stream: pointer to the stream object * @data: buffer to read into from stream * @nbytes: size of @data buffer - * @flags: extra flags; not used yet, so callers should always pass 0 + * @flags: bitwise-OR of virStreamRecvFlagsValues * * Reads a series of bytes from the stream. This method may * block the calling application for an arbitrary amount @@ -301,6 +301,29 @@ virStreamRecv(virStreamPtr stream, * nbytes, 0) is equivalent to calling virStreamRecv(stream, * data, nbytes) and vice versa. * + * If flag VIR_STREAM_RECV_STOP_AT_HOLE is set, this function + * will stop reading from stream if it has reached a hole. In + * that case, -3 is returned and virStreamHoleSize() should be

+ * called to get the hole size. An example using this flag might + * look like this: + * + * while (1) { + * char buf[4096]; + * + * int ret = virStreamRecvFlags(st, buf, len, VIR_STREAM_STOP_AT_HOLE); + * if (ret < 0) { + * if (ret == -3) { + * unsigned long long len; + * ret = virStreamHoleSize(st, &len);

+ * ...seek len bytes in target... + * } else { + * return -1; + * } + * } else { + * ...write buf to target... + * } + * }

+ * * Returns 0 when the end of the stream is reached, at * which time the caller should invoke virStreamFinish() * to get confirmation of stream completion. @@ -311,6 +334,9 @@ virStreamRecv(virStreamPtr stream, * * Returns -2 if there is no data pending to be read & the * stream is marked as non-blocking. + * + * Returns -3 if there is a hole in stream and caller requested + * to stop at a hole. */ int virStreamRecvFlags(virStreamPtr stream, @@ -332,6 +358,8 @@ virStreamRecvFlags(virStreamPtr stream, ret = (stream->driver->streamRecvFlags)(stream, data, nbytes, flags); if (ret == -2) return -2; + if (ret == -3) + return -3; if (ret < 0) goto error; return ret;