libbpf-cargo: Implement PartialEq for generated Rust "enums"

With the switch from emitting C enums as Rust enums to mapping them to
Rust struct instead, we dropped the PartialEq and Eq derives. Add them
back to make working with these generated types more convenient.

Signed-off-by: Daniel Müller <[email protected]>

Author: d-e-s-o

libbpf-cargo/src/gen/btf.rs

@@ -808,7 +808,7 @@ impl<'s> GenBtf<'s> {
 
         let mut first_field = None;
 
-        writeln!(def, r#"#[derive(Debug, Copy, Clone)]"#)?;
+        writeln!(def, r#"#[derive(Debug, Copy, Clone, Eq, PartialEq)]"#)?;
         writeln!(def, r#"#[repr(transparent)]"#)?;
         writeln!(def, r#"pub struct {enum_name}({signed}{repr_size});"#)?;
         writeln!(def, "#[allow(non_upper_case_globals)]")?;

libbpf-cargo/src/test.rs

@@ -377,7 +377,7 @@ fn test_make_workspace() {
         .exists());
 }
 
-fn build_rust_project_from_bpf_c(bpf_c: &str, rust: &str) {
+fn build_rust_project_from_bpf_c_impl(bpf_c: &str, rust: &str, run: bool) {
     let (_dir, proj_dir, cargo_toml) = setup_temp_project();
 
     // Add prog dir
@@ -434,7 +434,7 @@ fn build_rust_project_from_bpf_c(bpf_c: &str, rust: &str) {
         .expect("failed to write to main.rs");
 
     let status = Command::new("cargo")
-        .arg("build")
+        .arg(if run { "run" } else { "build" })
         .arg("--quiet")
         .arg("--manifest-path")
         .arg(cargo_toml.into_os_string())
@@ -444,6 +444,16 @@ fn build_rust_project_from_bpf_c(bpf_c: &str, rust: &str) {
     assert!(status.success());
 }
 
+fn build_rust_project_from_bpf_c(bpf_c: &str, rust: &str) {
+    let run = false;
+    build_rust_project_from_bpf_c_impl(bpf_c, rust, run)
+}
+
+fn run_rust_project_from_bpf_c(bpf_c: &str, rust: &str) {
+    let run = true;
+    build_rust_project_from_bpf_c_impl(bpf_c, rust, run)
+}
+
 #[test]
 fn test_skeleton_empty_source() {
     let bpf_c = String::new();
@@ -869,12 +879,15 @@ fn test_skeleton_enum_with_same_value_variants() {
         use bpf::*;
 
         fn main() {
-            let _zero1 = types::Foo::Zero;
-            let _zero2 = types::Foo::ZeroDup;
+            let zero1 = types::Foo::Zero;
+            let zero2 = types::Foo::ZeroDup;
+
+            assert_eq!(zero1, zero2);
+            assert_ne!(types::Foo::Zero, types::Foo::One);
         }
     "#
     .to_string();
-    let () = build_rust_project_from_bpf_c(&bpf_c, &rust);
+    let () = run_rust_project_from_bpf_c(&bpf_c, &rust);
 }
 
 #[test]
@@ -1865,7 +1878,7 @@ struct Bar bar;
 pub struct Bar {
     pub foo: Foo,
 }
-#[derive(Debug, Copy, Clone)]
+#[derive(Debug, Copy, Clone, Eq, PartialEq)]
 #[repr(transparent)]
 pub struct Foo(u32);
 #[allow(non_upper_case_globals)]
@@ -2603,7 +2616,7 @@ struct Foo foo;
 pub struct Foo {
     pub test: __anon_1,
 }
-#[derive(Debug, Copy, Clone)]
+#[derive(Debug, Copy, Clone, Eq, PartialEq)]
 #[repr(transparent)]
 pub struct __anon_1(u32);
 #[allow(non_upper_case_globals)]