Build Rust library

app/build.gradle.kts

@@ -1,8 +1,11 @@
+import com.nishtahir.CargoBuildTask
+
 plugins {
  id("com.android.application")
  kotlin("android")
  kotlin("kapt")
  id("dagger.hilt.android.plugin")
+ id("org.mozilla.rust-android-gradle.rust-android")
 }
 
 android {
@@ -70,13 +73,19 @@ android {
  }
 }
 
+cargo {
+ module = "src/main/rust"
+ libname = "crossword"
+ targets = listOf("arm", "arm64", "x86_64")
+}
+
 dependencies {
 
- implementation("org.jetbrains.kotlin:kotlin-stdlib:${libs.versions.kotlin.get()}")
+ implementation(libs.kotlin.stdlib)
  implementation("org.jetbrains.kotlinx:kotlinx-coroutines-android:1.6.4")
 
- implementation("com.google.dagger:hilt-android:${libs.versions.hilt.get()}")
- kapt("com.google.dagger:hilt-compiler:${libs.versions.hilt.get()}")
+ implementation(libs.hilt.android)
+ kapt(libs.hilt.compiler)
 
  implementation("androidx.core:core-ktx:1.12.0")
  implementation("androidx.appcompat:appcompat:1.6.1")
@@ -102,3 +111,7 @@ dependencies {
 kapt {
  correctErrorTypes = true
 }
+
+tasks.preBuild.configure {
+ dependsOn.add(tasks.withType(CargoBuildTask::class.java))
+}

app/src/main/java/xyz/lukasz/xword/CrosswordHelperApplication.kt

@@ -15,6 +15,7 @@ class CrosswordHelperApplication : Application() {
  companion object {
  init {
  System.loadLibrary("native-lib")
+ System.loadLibrary("crossword")
  }
  }
 }

app/src/main/java/xyz/lukasz/xword/search/MissingLettersIndex.kt

@@ -1,6 +1,7 @@
 package xyz.lukasz.xword.search
 
 import android.content.res.AssetManager
+import timber.log.Timber
 import xyz.lukasz.xword.interop.NativeSharedPointer
 import java.util.*
 
@@ -15,6 +16,7 @@ class MissingLettersIndex(locale: Locale) : WordIndex(locale) {
  */
  override fun loadFromAsset(assetManager: AssetManager) {
  unload()
+ Timber.w(helloWorld())
  val assetPath = resolveAssetPath()
  val threadCount = Runtime.getRuntime().availableProcessors()
  nativeIndex = loadNative(assetManager, assetPath, threadCount)
@@ -30,4 +32,6 @@ class MissingLettersIndex(locale: Locale) : WordIndex(locale) {
  */
  private external fun loadNative(assetManager: AssetManager, filename: String, threads: Int)
  : NativeSharedPointer
+
+ private external fun helloWorld(): String
 }

app/src/main/rust/.gitignore

@@ -0,0 +1 @@
+target/

app/src/main/rust/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "crossword"
+version = "0.1.0"
+edition = "2021"
+
+[lib]
+crate-type = ["cdylib"]
+
+[target.'cfg(target_os="android")'.dependencies]
+jni = { version = "0.21.1" }

app/src/main/rust/src/lib.rs

@@ -0,0 +1,20 @@
+//#[cfg(target_os="android")]
+#[allow(non_snake_case)]
+pub mod android {
+
+ use jni::JNIEnv;
+ use jni::objects::{JClass, JString};
+ use jni::sys::{jstring};
+
+ use std::ffi::{CString};
+
+ #[no_mangle]
+ pub unsafe extern fn Java_xyz_lukasz_xword_search_MissingLettersIndex_helloWorld(env: JNIEnv, _: JClass) -> jstring {
+ // Our Java companion code might pass-in "world" as a string, hence the name.
+ //let world = rust_greeting(env.get_string(java_pattern).expect("invalid pattern string").as_ptr());
+ // Retake pointer so that we can use it below and allow memory to be freed when it goes out of scope.
+ let world_ptr = CString::new("XDDDDDD").expect("cannot create cstring");
+ let output = env.new_string(world_ptr.to_str().unwrap()).expect("Couldn't create java string!");
+ output.into_raw()
+ }
+}

build.gradle.kts

@@ -1,14 +1,7 @@
 buildscript {
-
- repositories {
- google()
- mavenCentral()
- }
-
  dependencies {
  classpath("com.android.tools.build:gradle:8.1.2")
  classpath("org.jetbrains.kotlin:kotlin-gradle-plugin:${libs.versions.kotlin.get()}")
- classpath("com.google.dagger:hilt-android-gradle-plugin:${libs.versions.hilt.get()}")
  }
 }
 
@@ -19,6 +12,12 @@ allprojects {
  }
 }
 
+plugins {
+ id("org.mozilla.rust-android-gradle.rust-android").version("0.9.3")
+ id("com.google.dagger.hilt.android").version(libs.versions.hilt.get()).apply(false)
+}
+
+
 tasks.register<Delete>("clean") {
  delete(rootProject.buildDir)
 }