rust/protobuf: use prost-build to generate Rust protobuf files

We make a small cli tool, used in CMakeLists, similar to nanopb.

The generated file lands in the source folder and is committed. I
prefer this over generating into the build folder. The advantages are:

- Less reliance on the tool to work when you check out and old commit
- The rust crates do not depend on CMake in this way, which should
make it easier to use standard Rust tooling (though more work is
- needed there).

Author: benma

messages/CMakeLists.txt

@@ -51,6 +51,15 @@ add_custom_command(
     --proto_path=${CMAKE_CURRENT_SOURCE_DIR}
     '--nanopb_out=-I${CMAKE_CURRENT_SOURCE_DIR}:${CMAKE_CURRENT_BINARY_DIR}'
     ${PROTO_FILES_ABSOLUTE}
+  # We build the Rust protobuf files here and put them straight into the crate.
+  # This way, the crate can be compiled and tested without relying on cmake environment vars.
+  # Using prost-build the normal way was part of build.rs does not work due to a cargo bug:
+  # https://github.com/danburkert/prost/issues/344#issuecomment-650721245
+  COMMAND
+  ${CMAKE_COMMAND} -E env
+    OUT_DIR=${CMAKE_SOURCE_DIR}/src/rust/bitbox02-rust/src/hww/api/
+    MESSAGES_DIR=${CMAKE_CURRENT_SOURCE_DIR}
+    cargo run --manifest-path=${CMAKE_SOURCE_DIR}/tools/prost-build/Cargo.toml
 )
 
 add_custom_target(

src/CMakeLists.txt

@@ -484,7 +484,7 @@ foreach(type ${RUST_LIBS})
       # see src/rust/bitbox02-rust-c/src/lib.rs.
       # https://github.com/rust-lang/rust/issues/66740
       RUSTC_BOOTSTRAP=1
-      ${CARGO} build -v --features target-${type} --target-dir ${RUST_BINARY_DIR} ${RUST_CARGO_FLAG} ${RUST_TARGET_ARCH_ARG}
+      ${CARGO} build --features target-${type} --target-dir ${RUST_BINARY_DIR} ${RUST_CARGO_FLAG} ${RUST_TARGET_ARCH_ARG}
     COMMAND
       # Rust packages stdlib functions which we must remove/weaken on the arm target
       # Currently the removed symbols only clash in device-tests for some reason. Without this command, compiling device tests would result in errors like: