This is the shared IPC code between the debug router and the client debugger. It's not useful for random programs. Client debugging code should use the client debug library.
This is a super simple custom IPC format because it is intended to be used between two computers (unlike FIDL) and called at a very low level when debugging the system (when higher-level primitives should be avoided).
This library is shared between the client, which uses STL, and the userspace target code which uses FBL.
The FBL can be used in host code, but mandating a container style for a larger codebase from such a small stub seemed undesirable. The client uses many other STL containers and fbl::string's immutability provides challenges for code doing a lot of string manipulation that is not performance critical.
Since this shared library is so small, typedefs are provided that map to either STL or FBL containers, depending on the compilation environment. The code here must be written to the lowest common denominator of these two libraries.
Structs are defined with sized types and serialized little-endian such that they can be memcpy'd on little-endian machines.
Vectors are serialized as a 32-bit count followed by the number of records serialized in the normal manner.
Strings are serialized as a 32-bit size followed by the string data.