[libvirt] [PATCH v3 06/31] Introduce virStreamRecvHole

[Michal Privoznik]

This function is basically a counterpart for virStreamSendHole().
If one side of a stream called virStreamSendHole() the other
should call virStreamRecvHole() to get the size of the hole.

Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
---
 include/libvirt/libvirt-stream.h |  4 ++++
 src/driver-stream.h              |  6 ++++++
 src/libvirt-stream.c             | 44 ++++++++++++++++++++++++++++++++++++++++
 src/libvirt_public.syms          |  1 +
 4 files changed, 55 insertions(+)

diff --git a/include/libvirt/libvirt-stream.h b/include/libvirt/libvirt-stream.h
index 14c9af142..feaa8ad64 100644
--- a/include/libvirt/libvirt-stream.h
+++ b/include/libvirt/libvirt-stream.h
@@ -54,6 +54,10 @@ int virStreamSendHole(virStreamPtr st,
                       long long length,
                       unsigned int flags);
 
+int virStreamRecvHole(virStreamPtr,
+                      long long *length,
+                      unsigned int flags);
+
 
 /**
  * virStreamSourceFunc:
diff --git a/src/driver-stream.h b/src/driver-stream.h
index 0a5201431..0fb56ebd2 100644
--- a/src/driver-stream.h
+++ b/src/driver-stream.h
@@ -46,6 +46,11 @@ typedef int
                         long long length,
                         unsigned int flags);
 
+typedef int
+(*virDrvStreamRecvHole)(virStreamPtr st,
+                        long long *length,
+                        unsigned int flags);
+
 typedef int
 (*virDrvStreamEventAddCallback)(virStreamPtr stream,
                                 int events,
@@ -74,6 +79,7 @@ struct _virStreamDriver {
     virDrvStreamRecv streamRecv;
     virDrvStreamRecvFlags streamRecvFlags;
     virDrvStreamSendHole streamSendHole;
+    virDrvStreamRecvHole streamRecvHole;
     virDrvStreamEventAddCallback streamEventAddCallback;
     virDrvStreamEventUpdateCallback streamEventUpdateCallback;
     virDrvStreamEventRemoveCallback streamEventRemoveCallback;
diff --git a/src/libvirt-stream.c b/src/libvirt-stream.c
index a09896dcd..dc0dc9ea3 100644
--- a/src/libvirt-stream.c
+++ b/src/libvirt-stream.c
@@ -405,6 +405,50 @@ virStreamSendHole(virStreamPtr stream,
 }
 
 
+/**
+ * virStreamRecvHole:
+ * @stream: pointer to the stream object
+ * @length: number of bytes to skip
+ * @flags: extra flags; not used yet, so callers should always pass 0
+ *
+ * This API is used to determine the @length in bytes of the
+ * empty space to be created in a @stream's target file when
+ * uploading or downloading sparsely populated files. This is the
+ * counterpart to virStreamSendHole().
+ *
+ * Returns 0 on success,
+ *        -1 on error or when there's currently no hole in the stream
+ */
+int
+virStreamRecvHole(virStreamPtr stream,
+                  long long *length,
+                  unsigned int flags)
+{
+    VIR_DEBUG("stream=%p, length=%p flags=%x",
+              stream, length, flags);
+
+    virResetLastError();
+
+    virCheckStreamReturn(stream, -1);
+    virCheckNonNullArgReturn(length, -1);
+
+    if (stream->driver &&
+        stream->driver->streamRecvHole) {
+        int ret;
+        ret = (stream->driver->streamRecvHole)(stream, length, flags);
+        if (ret < 0)
+            goto error;
+        return ret;
+    }
+
+    virReportUnsupportedError();
+
+ error:
+    virDispatchError(stream->conn);
+    return -1;
+}
+
+
 /**
  * virStreamSendAll:
  * @stream: pointer to the stream object
diff --git a/src/libvirt_public.syms b/src/libvirt_public.syms
index 3be7cc6a0..b73cc8af1 100644
--- a/src/libvirt_public.syms
+++ b/src/libvirt_public.syms
@@ -762,6 +762,7 @@ LIBVIRT_3.1.0 {
 LIBVIRT_3.4.0 {
     global:
         virStreamRecvFlags;
+        virStreamRecvHole;
         virStreamSendHole;
 } LIBVIRT_3.1.0;
 
-- 
2.13.0