1 files changed, 95 insertions, 0 deletions
diff --git a/devices/src/virtio/video/response.rs b/devices/src/virtio/video/response.rs
new file mode 100644
index 0000000..e4b4385
--- /dev/null
+++ b/devices/src/virtio/video/response.rs
@@ -0,0 +1,95 @@
+// Copyright 2020 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+//! Data structures for commands of virtio video devices.
+
+use std::io;
+
+use data_model::{Le32, Le64};
+
+use crate::virtio::video::command::QueueType;
+use crate::virtio::video::control::*;
+use crate::virtio::video::format::*;
+use crate::virtio::video::params::Params;
+use crate::virtio::video::protocol::*;
+use crate::virtio::Writer;
+
+pub trait Response {
+    /// Writes an object to virtqueue.
+    fn write(&self, w: &mut Writer) -> Result<(), io::Error>;
+}
+
+/// A response to a `VideoCmd`. These correspond to `VIRTIO_VIDEO_RESP_*`.
+#[allow(dead_code)] // TODO(keiichiw): Remove this attribute
+#[derive(Debug)]
+pub enum CmdResponse {
+    NoData,
+    QueryCapability(Vec<FormatDesc>),
+    ResourceQueue {
+        timestamp: u64,
+        flags: u32,
+        size: u32,
+    },
+    GetParams {
+        queue_type: QueueType,
+        params: Params,
+    },
+    QueryControl(QueryCtrlResponse),
+    GetControl(CtrlVal),
+}
+
+impl Response for CmdResponse {
+    /// Writes a response to virtqueue.
+    fn write(&self, w: &mut Writer) -> Result<(), io::Error> {
+        use CmdResponse::*;
+
+        let type_ = Le32::from(match self {
+            NoData => VIRTIO_VIDEO_RESP_OK_NODATA,
+            QueryCapability(_) => VIRTIO_VIDEO_RESP_OK_QUERY_CAPABILITY,
+            ResourceQueue { .. } => VIRTIO_VIDEO_RESP_OK_RESOURCE_QUEUE,
+            GetParams { .. } => VIRTIO_VIDEO_RESP_OK_GET_PARAMS,
+            QueryControl(_) => VIRTIO_VIDEO_RESP_OK_QUERY_CONTROL,
+            GetControl(_) => VIRTIO_VIDEO_RESP_OK_GET_CONTROL,
+        });
+
+        let hdr = virtio_video_cmd_hdr {
+            type_,
+            ..Default::default()
+        };
+
+        match self {
+            NoData => w.write_obj(hdr),
+            QueryCapability(descs) => {
+                w.write_obj(virtio_video_query_capability_resp {
+                    hdr,
+                    num_descs: Le32::from(descs.len() as u32),
+                    ..Default::default()
+                })?;
+                descs.iter().map(|d| d.write(w)).collect()
+            }
+            ResourceQueue {
+                timestamp,
+                flags,
+                size,
+            } => w.write_obj(virtio_video_resource_queue_resp {
+                hdr,
+                timestamp: Le64::from(*timestamp),
+                flags: Le32::from(*flags),
+                size: Le32::from(*size),
+            }),
+            GetParams { queue_type, params } => {
+                let params = params.to_virtio_video_params(*queue_type);
+                w.write_obj(virtio_video_get_params_resp { hdr, params })
+            }
+            QueryControl(r) => {
+                w.write_obj(virtio_video_query_control_resp { hdr })?;
+                r.write(w)
+            }
+            GetControl(val) => {
+                w.write_obj(virtio_video_get_control_resp { hdr })?;
+                val.write(w)
+            }
+        }
+    }
+}