Merge "cherry pick: Create rust codelab via a Rust lib used by a system app" into main am: 4bed088780

Original change: https://android-review.googlesource.com/c/platform/development/+/2711374

Change-Id: Ib2e83a9a8f61f413a5d016477f32e6ae2f60afed
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>

samples/AconfigDemo/Android.bp

@@ -26,7 +26,7 @@ android_app {
         obfuscate: false,
         shrink_resources: true,
     },
-
+    required: ["libexample_rust_jni"],
     plugins: ["dagger2-compiler"]
 }
 
@@ -87,3 +87,19 @@ cc_library {
     ],
     export_include_dirs: ["src/include"],
 }
+
+rust_aconfig_library {
+    name: "libaconfig_demo_flags_rust",
+    crate_name: "aconfig_demo_flags_rust",
+    aconfig_declarations: "aconfig_demo_flags",
+}
+
+rust_ffi_shared {
+    name: "libexample_rust_jni",
+    crate_name: "example_rust_jni",
+    srcs: ["src/lib.rs"],
+    rustlibs: [
+        "libjni",
+        "libaconfig_demo_flags_rust",
+    ]
+}

samples/AconfigDemo/res/layout/main.xml

@@ -28,5 +28,6 @@
         android:textSize="25sp"
         android:autoText="true"
         android:capitalize="sentences"
+        android:scrollbars="vertical"
         android:textStyle="bold|italic"/>
 </LinearLayout>

samples/AconfigDemo/src/com/example/android/aconfig/demo/AconfigDemoActivity.java

@@ -22,6 +22,7 @@ import android.util.Log;
 import android.view.View;
 import android.view.WindowManager;
 import android.widget.TextView;
+import android.text.method.ScrollingMovementMethod;
 
 import com.example.android.aconfig.demo.flags.Flags;
 
@@ -43,6 +44,8 @@ public class AconfigDemoActivity extends Activity {
 
         setContentView(R.layout.main);
         TextView simpleTextView = (TextView) findViewById(R.id.simpleTextView);
+        simpleTextView.setMovementMethod(new ScrollingMovementMethod());
+
         simpleTextView.setText("Show Java Flags: \n\n");
 
         StaticContent cp = new StaticContent();
@@ -60,11 +63,16 @@ public class AconfigDemoActivity extends Activity {
         if (Flags.awesomeFlag2()) {
             Log.v("AconfigDemoActivity", Flags.FLAG_AWESOME_FLAG_2 + " is on!");
         }
+
+        simpleTextView.append("\n\nShow Rust Flags: \n\n");
+        simpleTextView.append(printRustFlag());
     }
 
     public native String printCFlag();
+    public native String printRustFlag();
 
     static {
         System.loadLibrary("example_cpp_lib");
+        System.loadLibrary("example_rust_jni");
     }
 }

samples/AconfigDemo/src/lib.rs

@@ -0,0 +1,46 @@
+//! example rust crate to be used in AconfigDemoActivity app
+
+use jni::objects::JClass;
+use jni::sys::jstring;
+use jni::JNIEnv;
+
+/// get flag value via static interface
+pub fn get_flag_via_static_interface() -> String {
+    format!(
+        "flag value: {}",
+        if aconfig_demo_flags_rust::append_static_content() { "true" } else { "false" }
+    )
+}
+
+/// get flag value via injection
+pub fn get_flag_via_injection_interface(
+    provider: &aconfig_demo_flags_rust::FlagProvider,
+) -> String {
+    format!("flag value: {}", if provider.append_injected_content() { "true" } else { "false" })
+}
+
+/// printRustFlag function
+#[no_mangle]
+#[allow(unused)]
+pub extern "system" fn Java_com_example_android_aconfig_demo_AconfigDemoActivity_printRustFlag<
+    'local,
+>(
+    mut env: JNIEnv<'local>,
+    class: JClass<'local>,
+) -> jstring {
+    let mut result = String::new();
+
+    result.push_str("flag name : append_static_content\n");
+    result.push_str("use pattern : static method\n");
+    result.push_str(&get_flag_via_static_interface());
+
+    result.push_str("\n\n");
+
+    result.push_str("flag name : append_injected_content\n");
+    result.push_str("use pattern : injection\n");
+    result.push_str(&get_flag_via_injection_interface(&aconfig_demo_flags_rust::PROVIDER));
+
+    let output = env.new_string(result).expect("Couldn't create java string!");
+
+    output.into_raw()
+}