# Build system

- Uses pipmake, a tiny build system which is pip-compatible, but forwards pip commands to a Makefile (e.g. `pip install` forwards to `make wheel`).
- The Makefile runs the script `makefile_helper.py,` which contains miscellaneous logic that's more convenient to write in python than in Makefile language. The output of this script is a file `makefile_helper.out`, containing variable declarations in Makefile language.
- Build the whole project with `make -j 32`. Compile time is high, so `make src_lib/FILE.o` may be useful when working on `src_lib/FILE.cu`.
- If you add a new source file, see comments near the top of `Makefile` for instructions on how to modify the makefile.

## Autogenerated kernels

 - Source files of the form `src_lib/autogenerated_kernels/*.cu` are autogenerated during the build process, with `python autogenerate_kernel.py src_lib/autogenerated_kernels/FILE.cu`.
 - The script `makefile_helper.py` decides which source files to autogenerate, and writes a list of filenames to `makefile_helper.out`.
 - Individual source files can be generated or compiled with `make src_lib/autogenerated_kernels/filename.{cu,o}`.
 - Each source file "registers" its precompiled kernel at library init time, and the registered kernels are found at runtime. (See examples in `PeakFindingKernel.hpp`.)

## gRPC

- Proto files live in `grpc/` (currently just [`grpc/frb_search.proto`](../grpc/frb_search.proto.md)).
- `make grpc` generates both C++ and Python files from `.proto` files.
- C++ generated files (`*.pb.{h,cc}`, `*.grpc.pb.{h,cc}`) are output to `grpc/`.
- Python generated files (`*_pb2.py`, `*_pb2_grpc.py`) are output to `pirate_frb/rpc/grpc/`.
- C++ generation uses `protoc` with `grpc_cpp_plugin`. Python generation uses `grpc_tools.protoc` followed by `protol` (protoletariat) to fix relative imports.
- Sentinel files (`*.protoc_cpp_sentinel`, `*.protoc_python_sentinel`) ensure each `protoc` invocation runs exactly once despite producing multiple output files.
- The shared library links against `-lgrpc++` and `-lprotobuf`.

## File Structure

```
include/pirate/*.hpp                - Public C++ headers
src_lib/*.cpp                       - Pure C++ implementations
src_lib/*.cu                        - CUDA implementations (kernels)
src_lib/autogenerated_kernels/*.cu  - Generated kernels (DO NOT EDIT)
pirate_frb/cuda_generator/*.py      - Python code that generates CUDA kernels
pirate_frb/*.py                     - High-level python interface
pirate_frb/rpc/                     - RPC client code (FrbClient.py)
pirate_frb/rpc/grpc/                - Generated Python protobuf/gRPC stubs
grpc/*.proto                        - Protocol buffer definitions
grpc/*.pb.{h,cc}                    - Generated C++ protobuf/gRPC code
bin/                                - Compiled executables
lib/libpirate.so                    - Shared library
```