commit f73b9632839caf94e12a046d0aeaac7e64375296
author Mårten Kongstad <amhk@google.com> Wed May 24 15:43:47 2023 +0200
committer Mårten Kongstad <amhk@google.com> Thu May 25 16:18:59 2023 +0200
tree 3678f45965520eafde2e0bc7c072cd1112c156d3
parent 993111f91c7cb12392666e6694006710924ccfde

aconfig: first iteration of Rust codegen

Add a new `create-rust-lib` command to generate Rust code. The output is
a src/lib.rs file; the build system is assumed to set the generated
crate's name.

For READ_ONLY flags, the generated code returns a hard-coded true or false.

For READ_WRITE flags, the generated code reaches out to DeviceConfig via
the cc_library server_configurable_flags via the
libprofcollect_libflags_rust Rust bindings. The build system is assumed
to add this to the generated crate's dependencies.

Note: libprofcollect_libflags_rust seems generic enough that it should
be moved to an official Rust wrapper for server_configurable_flags. This
is tracked in b/284096062.

Summary of module the built system is assumed to wrap the auto-generated
code in:

  rust_library {
      name: "lib<namespace>_rs",
      crate_name: "<namespace>_rs",
      edition: "2021",
      clippy_lints: "none",
      no_stdlibs: true,
      lints: "none",
      srcs: ["src/lib.rs"],
      rustlibs: [
          "libprofcollect_libflags_rust",
      ],
  }

Also add a set of test input to be used in the unit tests for a more
coherent test strategy. A follow-up CL will migrate the code in
commands.rs, codegen_java.rs and codegen_cpp.rs.

Bug: 279483360
Bug: 283907905
Test: atest aconfig.test
Test: manual: create cache from files in testdata, create rust lib, add to module template above, verify the module builds
Change-Id: I02606aa3686eda921116e33f7e2df8fd1156a7aa

tools/aconfig/src/main.rs

diff --git a/tools/aconfig/src/main.rs b/tools/aconfig/src/main.rs
index d02307d..b60909b 100644
--- a/tools/aconfig/src/main.rs
+++ b/tools/aconfig/src/main.rs
@@ -28,6 +28,7 @@
 mod cache;
 mod codegen_cpp;
 mod codegen_java;
+mod codegen_rust;
 mod commands;
 mod protos;
 
@@ -55,6 +56,11 @@
                 .arg(Arg::new("out").long("out").required(true)),
         )
         .subcommand(
+            Command::new("create-rust-lib")
+                .arg(Arg::new("cache").long("cache").required(true))
+                .arg(Arg::new("out").long("out").required(true)),
+        )
+        .subcommand(
             Command::new("dump")
                 .arg(Arg::new("cache").long("cache").action(ArgAction::Append).required(true))
                 .arg(
@@ -129,6 +135,14 @@
             let generated_file = commands::create_cpp_lib(&cache)?;
             write_output_file_realtive_to_dir(&dir, &generated_file)?;
         }
+        Some(("create-rust-lib", sub_matches)) => {
+            let path = get_required_arg::<String>(sub_matches, "cache")?;
+            let file = fs::File::open(path)?;
+            let cache = Cache::read_from_reader(file)?;
+            let dir = PathBuf::from(get_required_arg::<String>(sub_matches, "out")?);
+            let generated_file = commands::create_rust_lib(&cache)?;
+            write_output_file_realtive_to_dir(&dir, &generated_file)?;
+        }
         Some(("dump", sub_matches)) => {
             let mut caches = Vec::new();
             for path in sub_matches.get_many::<String>("cache").unwrap_or_default() {