[Spice-devel] [spice-common PATCH v3] Add LZ4 data compression and used it in spicevmc channel

[Frediano Ziglio]

> 
> Compressed message type is CompressedData which contains compression
> type (1 byte) followed by the uncompressed data size (4 bytes) followed
> by the compressed data size (4 bytes) followed by the compressed data
> ---
>  common/client_marshallers.h |  1 +
>  common/messages.h           |  7 +++++++
>  spice.proto                 | 15 +++++++++++++++
>  3 files changed, 23 insertions(+)
> 
> diff --git a/common/client_marshallers.h b/common/client_marshallers.h
> index 728987e..2074323 100644
> --- a/common/client_marshallers.h
> +++ b/common/client_marshallers.h
> @@ -33,6 +33,7 @@ SPICE_BEGIN_DECLS
>  typedef struct {
>      void (*msg_SpiceMsgEmpty)(SpiceMarshaller *m, SpiceMsgEmpty *msg);
>      void (*msg_SpiceMsgData)(SpiceMarshaller *m, SpiceMsgData *msg);
> +    void (*msg_SpiceMsgCompressedData)(SpiceMarshaller *m,
> SpiceMsgCompressedData *msg);
>      void (*msgc_ack_sync)(SpiceMarshaller *m, SpiceMsgcAckSync *msg);
>      void (*msgc_pong)(SpiceMarshaller *m, SpiceMsgPing *msg);
>      void (*msgc_disconnecting)(SpiceMarshaller *m, SpiceMsgDisconnect *msg);
> diff --git a/common/messages.h b/common/messages.h
> index f537950..d001850 100644
> --- a/common/messages.h
> +++ b/common/messages.h
> @@ -55,6 +55,13 @@ typedef struct SpiceMsgData {
>      uint8_t data[0];
>  } SpiceMsgData;
>  
> +typedef struct SpiceMsgCompressedData {
> +    uint8_t type;
> +    uint32_t uncompressed_size;
> +    uint32_t compressed_size;
> +    uint8_t compressed_data[0];
> +} SpiceMsgCompressedData;
> +
>  typedef struct SpiceMsgEmpty {
>      uint8_t padding;
>  } SpiceMsgEmpty;
> diff --git a/spice.proto b/spice.proto
> index 4a0778d..ad210ca 100644
> --- a/spice.proto
> +++ b/spice.proto
> @@ -120,6 +120,19 @@ message Data {
>      uint8 data[] @end @ctype(uint8_t);
>  } @nocopy;
>  
> +enum8 data_compression_type {
> +    INVALID,
> +    NONE,
> +    LZ4,
> +};
> +
> +message CompressedData {
> +    data_compression_type type;
> +    uint32 uncompressed_size;
> +    uint32 compressed_size;
> +    uint8 compressed_data[] @end;
> +} @ctype(SpiceMsgCompressedData);
> +

Just a consideration. What's the size of compressed_data array?
Why not using @as_ptr attribute and remove the compressed_size field?
In this way you'll save 4 bytes for every packet.

>  struct ChannelWait {
>      uint8 channel_type;
>      uint8 channel_id;
> @@ -1373,8 +1386,10 @@ channel SmartcardChannel : BaseChannel {
>  channel SpicevmcChannel : BaseChannel {
>  server:
>      Data data = 101;
> +    CompressedData compressed_data = 102;
>  client:
>      Data data = 101;
> +    CompressedData compressed_data = 102;
>  };
>  
>  channel UsbredirChannel : SpicevmcChannel {

Frediano