[clang] [clang][MBD] set up module build daemon infrastructure (PR #67562)

[Connor Sughrue via cfe-commits]

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@@ -0,0 +1,134 @@
+//===------------------------- SocketMsgSupport.h -------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLING_MODULEBUILDDAEMON_SOCKETMSGSUPPORT_H
+#define LLVM_CLANG_TOOLING_MODULEBUILDDAEMON_SOCKETMSGSUPPORT_H
+
+#include "clang/Tooling/ModuleBuildDaemon/Client.h"
+#include "clang/Tooling/ModuleBuildDaemon/SocketSupport.h"
+
+using namespace clang;
+using namespace llvm;
+
+namespace cc1modbuildd {
+
+enum class ActionType { HANDSHAKE };
+enum class StatusType { REQUEST, SUCCESS, FAILURE };
+
+struct BaseMsg {
+  ActionType MsgAction;
+  StatusType MsgStatus;
+
+  BaseMsg() = default;
+  BaseMsg(ActionType Action, StatusType Status)
+      : MsgAction(Action), MsgStatus(Status) {}
+};
+
+struct HandshakeMsg : public BaseMsg {
+  HandshakeMsg() = default;
+  HandshakeMsg(ActionType Action, StatusType Status)
+      : BaseMsg(Action, Status) {}
+};
+
+template <typename T> std::string getBufferFromSocketMsg(T Msg) {
+  static_assert(std::is_base_of<cc1modbuildd::BaseMsg, T>::value,
+                "T must inherit from cc1modbuildd::BaseMsg");
+
+  std::string Buffer;
+  llvm::raw_string_ostream OS(Buffer);
+  llvm::yaml::Output YamlOut(OS);
+
+  YamlOut << Msg;
+  return Buffer;
+}
+
+template <typename T> Expected<T> getSocketMsgFromBuffer(StringRef Buffer) {
+  static_assert(std::is_base_of<cc1modbuildd::BaseMsg, T>::value,
+                "T must inherit from cc1modbuildd::BaseMsg");
+
+  T ClientRequest;
+  llvm::yaml::Input YamlIn(Buffer);
+  YamlIn >> ClientRequest;
+
+  if (YamlIn.error()) {
+    std::string Msg = "Syntax or semantic error during YAML parsing";
----------------
cpsughrue wrote:

`YamlIn.error()` dumps an error message describing the syntax or semantic error if there is one. I added a comment explaining that

https://github.com/llvm/llvm-project/pull/67562