Merge "Migrate profcollectd's libflags bindings from bindgen to cxx."

5 files changed, 36 insertions, 38 deletions

diff --git a/profcollectd/libprofcollectd/bindings/libflags/Android.bp b/profcollectd/libprofcollectd/bindings/libflags/Android.bp
index 102a6c05..fb846678 100644
--- a/profcollectd/libprofcollectd/bindings/libflags/Android.bp
+++ b/profcollectd/libprofcollectd/bindings/libflags/Android.bp
@@ -26,20 +26,23 @@ package {
 cc_library_static {
     name: "libprofcollect_libflags",
     srcs: ["get_flags.cpp"],
+    generated_headers: ["cxx-bridge-header"],
+    generated_sources: ["libprofcollect_libflags_bridge_code"],
 }
 
-rust_bindgen {
-    name: "libprofcollect_libflags_bindgen",
-    wrapper_src: "get_flags.hpp",
-    crate_name: "profcollect_libflags_bindgen",
-    source_stem: "bindings",
+genrule {
+    name: "libprofcollect_libflags_bridge_code",
+    tools: ["cxxbridge"],
+    cmd: "$(location cxxbridge) $(in) >> $(out)",
+    srcs: ["lib.rs"],
+    out: ["libprofcollect_libflags_cxx_generated.cc"],
 }
 
 rust_library {
     name: "libprofcollect_libflags_rust",
     crate_name: "profcollect_libflags_rust",
     srcs: ["lib.rs"],
-    rlibs: ["libprofcollect_libflags_bindgen"],
+    rustlibs: ["libcxx"],
     static_libs: ["libprofcollect_libflags"],
     shared_libs: [
         "libc++",
diff --git a/profcollectd/libprofcollectd/bindings/libflags/get_flags.cpp b/profcollectd/libprofcollectd/bindings/libflags/get_flags.cpp
index e5ce65a1..d8bab841 100644
--- a/profcollectd/libprofcollectd/bindings/libflags/get_flags.cpp
+++ b/profcollectd/libprofcollectd/bindings/libflags/get_flags.cpp
@@ -17,12 +17,9 @@
 #include "../../../../../server_configurable_flags/libflags/include/server_configurable_flags/get_flags.h"
 #include "get_flags.hpp"
 
-const char* GetServerConfigurableFlag(const char* experiment_category_name,
-                                      const char* experiment_flag_name,
-                                      const char* default_value) {
-    auto v = server_configurable_flags::GetServerConfigurableFlag(
-        std::string(experiment_category_name),
-        std::string(experiment_flag_name),
-        std::string(default_value));
-    return strdup(v.c_str());
+rust::String GetServerConfigurableFlag(rust::Str experiment_category_name,
+                                       rust::Str experiment_flag_name, rust::Str default_value) {
+  return server_configurable_flags::GetServerConfigurableFlag(std::string(experiment_category_name),
+                                                              std::string(experiment_flag_name),
+                                                              std::string(default_value));
 }
diff --git a/profcollectd/libprofcollectd/bindings/libflags/get_flags.hpp b/profcollectd/libprofcollectd/bindings/libflags/get_flags.hpp
index ab3be989..a42c52e8 100644
--- a/profcollectd/libprofcollectd/bindings/libflags/get_flags.hpp
+++ b/profcollectd/libprofcollectd/bindings/libflags/get_flags.hpp
@@ -14,5 +14,8 @@
  * limitations under the License.
  */
 
-// C declaration for bindgen.
-const char* GetServerConfigurableFlag(const char*, const char*, const char*);
+#pragma once
+
+#include "rust/cxx.h"
+
+rust::String GetServerConfigurableFlag(rust::Str, rust::Str, rust::Str);
diff --git a/profcollectd/libprofcollectd/bindings/libflags/lib.rs b/profcollectd/libprofcollectd/bindings/libflags/lib.rs
index c8875cb1..c6435bbd 100644
--- a/profcollectd/libprofcollectd/bindings/libflags/lib.rs
+++ b/profcollectd/libprofcollectd/bindings/libflags/lib.rs
@@ -17,27 +17,22 @@
 //! This module implements safe wrappers for GetServerConfigurableFlag method
 //! from libflags.
 
-use std::ffi::{CStr, CString};
+pub use ffi::GetServerConfigurableFlag;
 
-/// Use the category name and flag name registered in SettingsToPropertiesMapper.java
-/// to query the experiment flag value. This method will return default_value if
-/// querying fails.
-/// Note that for flags from Settings.Global, experiment_category_name should
-/// always be global_settings.
-pub fn get_server_configurable_flag<'a>(
-    experiment_category_name: &str,
-    experiment_flag_name: &str,
-    default_value: &'a str,
-) -> &'a str {
-    let experiment_category_name = CString::new(experiment_category_name).unwrap();
-    let experiment_flag_name = CString::new(experiment_flag_name).unwrap();
-    let default_value = CString::new(default_value).unwrap();
-    unsafe {
-        let cstr = profcollect_libflags_bindgen::GetServerConfigurableFlag(
-            experiment_category_name.as_ptr(),
-            experiment_flag_name.as_ptr(),
-            default_value.as_ptr(),
-        );
-        CStr::from_ptr(cstr).to_str().unwrap()
+#[cxx::bridge]
+mod ffi {
+    unsafe extern "C++" {
+        include!("get_flags.hpp");
+
+        /// Use the category name and flag name registered in SettingsToPropertiesMapper.java
+        /// to query the experiment flag value. This method will return default_value if
+        /// querying fails.
+        /// Note that for flags from Settings.Global, experiment_category_name should
+        /// always be global_settings.
+        fn GetServerConfigurableFlag(
+            experiment_category_name: &str,
+            experiment_flag_name: &str,
+            default_value: &str,
+        ) -> String;
     }
 }
diff --git a/profcollectd/libprofcollectd/config.rs b/profcollectd/libprofcollectd/config.rs
index e7dac241..bc41e99e 100644
--- a/profcollectd/libprofcollectd/config.rs
+++ b/profcollectd/libprofcollectd/config.rs
@@ -107,7 +107,7 @@ where
     T::Err: Error + Send + Sync + 'static,
 {
     let default_value = default_value.to_string();
-    let config = profcollect_libflags_rust::get_server_configurable_flag(
+    let config = profcollect_libflags_rust::GetServerConfigurableFlag(
         &PROFCOLLECT_CONFIG_NAMESPACE,
         &key,
         &default_value,