proxy_data.h 文件参考

Routing envelope used by the VLink proxy / monitoring path. 更多...

#include <cstdint>
#include <string_view>
#include "../base/bytes.h"

proxy_data.h 的引用(Include)关系图:

浏览源代码.

命名空间
	vlink
	vlink::zerocopy

函数
struct	vlink::zerocopy::VLINK_EXPORT_AND_ALIGNED (8) AudioFrame final

详细描述

Routing envelope used by the VLink proxy / monitoring path.

ProxyData bundles a serialised user payload with the metadata that the VLink proxy subsystem needs to forward the message across hosts: topic URL, serialisation type label, source hostname, plus control fields (control id, mode, microsecond timestamp, sequence number, coarse schema family). All variable-length regions share a single owned allocation so a freshly deserialised envelope can expose each region as a string_view or shallow Bytes without further allocation.

Region	Meaning
raw	Serialised user message bytes
url	Topic URL (e.g. "dds://my/topic")
ser	Serialisation type label (e.g. "proto.MyMsg")
hostname	Source machine identifier (optional)

Wire format

ProxyData is POD; memcpy serialises the struct. The sizeof value is locked by static_assert and forms a permanent contract: the vlink::zerocopy::* containers have NO forward or backward binary compatibility across releases. Pointer / ownership fields inside the wire snapshot must NEVER be interpreted by remote consumers.

static_assert(sizeof(ProxyData) == 80, "Sizeof must be 80 bytes.");

Memory layout

Offset  Size  Field
------  ----  ---------------------------------
     0     8  uint8_t* data_
     8     8  size_t   size_
    16     4  uint32_t control_id_
    20     4  uint32_t mode_
    24     8  int64_t  timestamp_
    32     8  int64_t  seq_
    40     4  uint32_t data_pos_
    44     4  uint32_t data_size_
    48     4  uint32_t url_pos_
    52     4  uint32_t url_size_
    56     4  uint32_t ser_pos_
    60     4  uint32_t ser_size_
    64     4  uint32_t hostname_pos_
    68     4  uint32_t hostname_size_
    72     4  uint32_t schema_
    76     1  bool     is_owner_
    77     1  uint8_t  reserved_buf_
    78     2  uint16_t reserved_buf2_
------  ----  ---------------------------------
 Total    80  bytes (alignas 8)
 
Wire envelope:
[ magic_begin (4) | version (4) | ProxyData struct (80) | raw | url | ser | hostname | magic_end (4) ]

Reserved bytes

The 3 bytes that follow is_owner_ are exposed as two explicit wire-locked fields: uint8_t reserved_buf_ (offset 77) and uint16_t reserved_buf2_ (offset 78), reachable through get_reserved() / get_reserved2(). They travel through the wire format and are carried by the copy / move helpers, but MUST NOT be repurposed by application code: future library revisions may bind them to real fields.

Example

vlink::zerocopy::ProxyData envelope;
envelope.set_control_id(42);
envelope.set_timestamp(vlink::time_us());
envelope.create(payload, "dds://lidar/top", "proto.PointCloud",
                static_cast<uint32_t>(SchemaType::kProtobuf), "host-a");
 
vlink::Bytes wire;
envelope >> wire;
 
vlink::zerocopy::ProxyData rx;
rx << wire;
auto url = rx.url();