[llvm-branch-commits] [lldb] [lldbremote][NFC] Factor out code handling breakpoint packets (PR #192915)

[David Spickett via llvm-branch-commits]

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@@ -307,6 +307,34 @@ class GDBRemoteCommunicationServerLLGS
 private:
   llvm::Expected<std::unique_ptr<llvm::MemoryBuffer>> BuildTargetXml();
 
+  /// Helper struct for the Execute{Set,Remove}Breakpoint methods.
+  struct BreakpointResult {
+    enum class Kind { OK, Error, IllFormed };
+
+    Kind kind;
+    uint8_t error_code = 0; // Only meaningful when kind == Error.
+    std::string message;    // Only meaningful when kind == IllFormed.
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DavidSpickett wrote:

This feels like a discriminated union but without the union, and C++ has discriminated union with std::variant. Only problem is the OK state which doesn't have a type as such, which I think is what https://en.cppreference.com/cpp/utility/variant/monostate is for? (first time I've come across that myself)

Does std::variant fit here or is it awkward to handle? You could use a variant as a member of this class and then you still have the `Create...` which are more intuitive than knowing what type to set. Then the variant handles the enum/union part for you.

Your `switch (result.kind) {` above would become std::visit.

https://github.com/llvm/llvm-project/pull/192915