From e610f2dc1ec06e1e8ce04e4055bc7bd1fa4cfaa3 Mon Sep 17 00:00:00 2001
From: stli <lst92991@gmail.com>
Date: Sat, 11 Apr 2026 10:27:05 +0800
Subject: [PATCH] Add protobuf COM wrapper

---
 KeyBorad/KeyBorad/COM/Com_PbCodec.cpp | 142 ++++++++++++++++++++++++++
 KeyBorad/KeyBorad/COM/Com_PbCodec.h   |  17 +++
 docs/host_com_rebuild.md              |  25 +++++
 3 files changed, 184 insertions(+)
 create mode 100644 KeyBorad/KeyBorad/COM/Com_PbCodec.cpp
 create mode 100644 KeyBorad/KeyBorad/COM/Com_PbCodec.h

diff --git a/KeyBorad/KeyBorad/COM/Com_PbCodec.cpp b/KeyBorad/KeyBorad/COM/Com_PbCodec.cpp
new file mode 100644
index 0000000..004b29d
--- /dev/null
+++ b/KeyBorad/KeyBorad/COM/Com_PbCodec.cpp
@@ -0,0 +1,142 @@
+#include "COM/Com_PbCodec.h"
+
+#include "COM/Com_CdcEncode.h"
+
+namespace
+{
+
+quint32 Com_Pb_Func_CalcFrameChecksum(const keyboard::cdc::CdcFrame& Frame)
+{
+    QByteArray ByteArray;
+    ByteArray.append(static_cast<char>(Frame.head1()));
+    ByteArray.append(static_cast<char>(Frame.head2()));
+    ByteArray.append(static_cast<char>(Frame.payload_length()));
+    ByteArray.append(static_cast<char>(Frame.type()));
+    ByteArray.append(QByteArray::fromStdString(Frame.payload()));
+
+    return Com_Cdc_Func_CalcChecksum(ByteArray);
+}
+
+keyboard::cdc::CdcFrame Com_Pb_Func_BuildFrame(
+    keyboard::cdc::CdcPacketType Type,
+    const keyboard::cdc::CdcPacketBody& Body)
+{
+    keyboard::cdc::CdcFrame Frame;
+    std::string PayloadBytes;
+
+    Body.SerializeToString(&PayloadBytes);
+
+    Frame.set_head1(0xAA);
+    Frame.set_head2(0x55);
+    Frame.set_payload_length(static_cast<quint32>(PayloadBytes.size()));
+    Frame.set_type(Type);
+    Frame.set_payload(PayloadBytes);
+    Frame.set_checksum(Com_Pb_Func_CalcFrameChecksum(Frame));
+    return Frame;
+}
+
+bool Com_Pb_Func_IsValidFrame(const keyboard::cdc::CdcFrame& Frame)
+{
+    return (Frame.head1() == 0xAA) &&
+        (Frame.head2() == 0x55) &&
+        (Frame.payload_length() == static_cast<quint32>(Frame.payload().size())) &&
+        (Frame.checksum() == Com_Pb_Func_CalcFrameChecksum(Frame));
+}
+
+} // namespace
+
+bool Com_Pb_Func_SerializeFrame(
+    const keyboard::cdc::CdcFrame& Frame,
+    QByteArray* p_ByteArray)
+{
+    if (p_ByteArray == nullptr)
+    {
+        return false;
+    }
+
+    std::string Bytes;
+    if (!Frame.SerializeToString(&Bytes))
+    {
+        p_ByteArray->clear();
+        return false;
+    }
+
+    *p_ByteArray = QByteArray(Bytes.data(), static_cast<int>(Bytes.size()));
+    return true;
+}
+
+bool Com_Pb_Func_ParseFrame(
+    const QByteArray& ByteArray,
+    keyboard::cdc::CdcFrame* p_Frame)
+{
+    if (p_Frame == nullptr)
+    {
+        return false;
+    }
+
+    keyboard::cdc::CdcFrame Frame;
+    if (!Frame.ParseFromArray(ByteArray.constData(), ByteArray.size()))
+    {
+        return false;
+    }
+
+    if (!Com_Pb_Func_IsValidFrame(Frame))
+    {
+        return false;
+    }
+
+    *p_Frame = Frame;
+    return true;
+}
+
+QByteArray Com_Pb_Func_BuildHelloReqFrame()
+{
+    keyboard::cdc::CdcPacketBody Body;
+    Body.mutable_hello_req()->set_protocol_version(1);
+
+    const keyboard::cdc::CdcFrame Frame =
+        Com_Pb_Func_BuildFrame(keyboard::cdc::CDC_PACKET_TYPE_HELLO_REQ, Body);
+
+    QByteArray ByteArray;
+    if (!Com_Pb_Func_SerializeFrame(Frame, &ByteArray))
+    {
+        return QByteArray();
+    }
+
+    return ByteArray;
+}
+
+bool Com_Pb_Func_ParseHelloRspFrame(
+    const QByteArray& ByteArray,
+    keyboard::cdc::HelloRsp* p_HelloRsp)
+{
+    if (p_HelloRsp == nullptr)
+    {
+        return false;
+    }
+
+    keyboard::cdc::CdcFrame Frame;
+    if (!Com_Pb_Func_ParseFrame(ByteArray, &Frame))
+    {
+        return false;
+    }
+
+    if (Frame.type() != keyboard::cdc::CDC_PACKET_TYPE_HELLO_RSP)
+    {
+        return false;
+    }
+
+    keyboard::cdc::CdcPacketBody Body;
+    if (!Body.ParseFromString(Frame.payload()))
+    {
+        return false;
+    }
+
+    if (!Body.has_hello_rsp())
+    {
+        return false;
+    }
+
+    *p_HelloRsp = Body.hello_rsp();
+    return true;
+}
diff --git a/KeyBorad/KeyBorad/COM/Com_PbCodec.h b/KeyBorad/KeyBorad/COM/Com_PbCodec.h
new file mode 100644
index 0000000..af25db1
--- /dev/null
+++ b/KeyBorad/KeyBorad/COM/Com_PbCodec.h
@@ -0,0 +1,17 @@
+#pragma once
+
+#include <QtCore/QByteArray>
+
+#include "../generated/cpp/keyboard.pb.h"
+
+bool Com_Pb_Func_SerializeFrame(
+    const keyboard::cdc::CdcFrame& Frame,
+    QByteArray* p_ByteArray);
+bool Com_Pb_Func_ParseFrame(
+    const QByteArray& ByteArray,
+    keyboard::cdc::CdcFrame* p_Frame);
+
+QByteArray Com_Pb_Func_BuildHelloReqFrame();
+bool Com_Pb_Func_ParseHelloRspFrame(
+    const QByteArray& ByteArray,
+    keyboard::cdc::HelloRsp* p_HelloRsp);
diff --git a/docs/host_com_rebuild.md b/docs/host_com_rebuild.md
index 6189d4e..4eff245 100644
--- a/docs/host_com_rebuild.md
+++ b/docs/host_com_rebuild.md
@@ -82,6 +82,31 @@ Implemented behavior:
   - `Ack`
   - `Error`
 
+### Node 3: protobuf thin wrapper
+
+Files added in this step:
+
+- `KeyBorad/KeyBorad/COM/Com_PbCodec.h`
+- `KeyBorad/KeyBorad/COM/Com_PbCodec.cpp`
+
+Design notes:
+
+- stop expanding hand-written typed payload logic
+- let protobuf generated code own message encode/decode
+- keep only a thin Qt-friendly wrapper
+
+Implemented behavior:
+
+- serialize a full `CdcFrame`
+- parse and validate a full `CdcFrame`
+- build `HelloReq` using generated protobuf types
+- parse `HelloRsp` using generated protobuf types
+
+Current limit:
+
+- not wired into the project yet
+- protobuf runtime include and link setup is still pending
+
 ## COM done criteria
 
 For the current project stage, COM is considered done when: