Add Rust build support

.gitignore

@@ -47,3 +47,13 @@ crowdin.properties
 # Nix stuff
 .direnv/
 result
+
+# VSCode
+.vscode/
+
+# Rust
+debug/
+target/
+Cargo.lock
+**/*.rs.bk
+*.pdb

app/build.gradle.kts

@@ -101,12 +101,6 @@ android {
         kotlinCompilerExtensionVersion = libs.versions.androidx.compose.compiler.get()
     }
 
-    //externalNativeBuild {
-    //    cmake {
-    //        path("src/main/cpp/CMakeLists.txt")
-    //    }
-    //}
-
     buildTypes {
         named("debug") {
             applicationIdSuffix = ".debug"
@@ -152,11 +146,6 @@ android {
             initWith(getByName("release"))
             signingConfig = signingConfigs.getByName("debug")
             matchingFallbacks += listOf("release")
-
-            ndk {
-                // For running FlorisBoard on the emulator
-                abiFilters += listOf("x86", "x86_64")
-            }
         }
     }
 
@@ -214,8 +203,8 @@ dependencies {
     implementation(libs.patrickgold.jetpref.datastore.ui)
     implementation(libs.patrickgold.jetpref.material.ui)
 
-
     implementation(project(":lib:kotlin"))
+    implementation(project(":lib:native"))
 
     testImplementation(libs.equalsverifier)
     testImplementation(libs.kotest.assertions.core)

app/src/main/kotlin/dev/patrickgold/florisboard/FlorisApplication.kt

@@ -34,20 +34,17 @@ import dev.patrickgold.florisboard.ime.media.emoji.FlorisEmojiCompat
 import dev.patrickgold.florisboard.ime.nlp.NlpManager
 import dev.patrickgold.florisboard.ime.text.gestures.GlideTypingManager
 import dev.patrickgold.florisboard.ime.theme.ThemeManager
-import dev.patrickgold.florisboard.lib.NativeStr
 import dev.patrickgold.florisboard.lib.cache.CacheManager
 import dev.patrickgold.florisboard.lib.crashutility.CrashUtility
 import dev.patrickgold.florisboard.lib.devtools.Flog
 import dev.patrickgold.florisboard.lib.devtools.LogTopic
 import dev.patrickgold.florisboard.lib.devtools.flogError
-import dev.patrickgold.florisboard.lib.devtools.flogInfo
 import dev.patrickgold.florisboard.lib.ext.ExtensionManager
 import dev.patrickgold.florisboard.lib.io.AssetManager
 import dev.patrickgold.florisboard.lib.io.deleteContentsRecursively
-import dev.patrickgold.florisboard.lib.io.subFile
-import dev.patrickgold.florisboard.lib.toNativeStr
 import dev.patrickgold.jetpref.datastore.JetPref
 import org.florisboard.lib.kotlin.tryOrNull
+import org.florisboard.libnative.dummyAdd
 import java.lang.ref.WeakReference
 
 /**
@@ -59,13 +56,9 @@ private var FlorisApplicationReference = WeakReference<FlorisApplication?>(null)
 @Suppress("unused")
 class FlorisApplication : Application() {
     companion object {
-        private const val ICU_DATA_ASSET_PATH = "icu4c/icudt73l.dat"
-
-        private external fun nativeInitICUData(path: NativeStr): Int
-
         init {
             try {
-                System.loadLibrary("florisboard-native")
+                System.loadLibrary("fl_native")
             } catch (_: Exception) {
             }
         }
@@ -99,6 +92,7 @@ class FlorisApplication : Application() {
             )
             CrashUtility.install(this)
             FlorisEmojiCompat.init(this)
+            flogError { "dummy result: ${dummyAdd(3,4)}" }
 
             if (!UserManagerCompat.isUserUnlocked(this)) {
                 cacheDir?.deleteContentsRecursively()
@@ -115,7 +109,6 @@ class FlorisApplication : Application() {
     }
 
     fun init() {
-        initICU(this)
         cacheDir?.deleteContentsRecursively()
         prefs.initializeBlocking(this)
         extensionManager.value.init()
@@ -123,28 +116,6 @@ class FlorisApplication : Application() {
         DictionaryManager.init(this)
     }
 
-    fun initICU(context: Context): Boolean {
-        try {
-            val androidAssetManager = context.assets ?: return false
-            val icuTmpDataFile = context.cacheDir.subFile("icudt.dat")
-            icuTmpDataFile.outputStream().use { os ->
-                androidAssetManager.open(ICU_DATA_ASSET_PATH).use { it.copyTo(os) }
-            }
-            val status = nativeInitICUData(icuTmpDataFile.absolutePath.toNativeStr())
-            icuTmpDataFile.delete()
-            return if (status != 0) {
-                flogError { "Native ICU data initializing failed with error code $status!" }
-                false
-            } else {
-                flogInfo { "Successfully loaded ICU data!" }
-                true
-            }
-        } catch (e: Exception) {
-            flogError { e.toString() }
-            return false
-        }
-    }
-
     private inner class BootComplete : BroadcastReceiver() {
         override fun onReceive(context: Context?, intent: Intent?) {
             if (intent == null) return

lib/native/build.gradle.kts

@@ -0,0 +1,71 @@
+plugins {
+    alias(libs.plugins.agp.library)
+    alias(libs.plugins.kotlin.android)
+}
+
+val projectMinSdk: String by project
+val projectCompileSdk: String by project
+val projectNdkVersion: String by project
+
+android {
+    namespace = "org.florisboard.libnative"
+    compileSdk = projectCompileSdk.toInt()
+    ndkVersion = projectNdkVersion
+
+    defaultConfig {
+        minSdk = projectMinSdk.toInt()
+
+        externalNativeBuild {
+            cmake {
+                targets("fl_native")
+                arguments(
+                    "-DCMAKE_ANDROID_API=" + minSdk.toString(),
+                )
+            }
+        }
+
+        ndk {
+            //abiFilters += listOf("armeabi-v7a", "arm64-v8a")
+        }
+    }
+
+    buildTypes {
+        release {
+            isMinifyEnabled = false
+            proguardFiles(
+                getDefaultProguardFile("proguard-android-optimize.txt"),
+            )
+        }
+    }
+    compileOptions {
+        sourceCompatibility = JavaVersion.VERSION_1_8
+        targetCompatibility = JavaVersion.VERSION_1_8
+    }
+    kotlinOptions {
+        jvmTarget = "1.8"
+    }
+
+    sourceSets {
+        maybeCreate("main").apply {
+            java {
+                srcDirs("src/main/kotlin")
+            }
+        }
+    }
+
+    externalNativeBuild {
+        cmake {
+            path("src/main/rust/CMakeLists.txt")
+        }
+    }
+}
+
+tasks.named("clean") {
+    doLast {
+        delete("src/main/rust/target", "src/main/rust/Cargo.lock")
+    }
+}
+
+dependencies {
+    // none
+}

lib/native/src/main/AndroidManifest.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+
+</manifest>

lib/native/src/main/kotlin/org/florisboard/libnative/test.kt

@@ -0,0 +1,3 @@
+package org.florisboard.libnative
+
+external fun dummyAdd(a: Int, b: Int): Int

lib/native/src/main/rust/CMakeLists.txt

@@ -0,0 +1,53 @@
+cmake_minimum_required(VERSION 3.22)
+
+project(florisboard)
+
+if(WIN32)
+    set(USER_HOME_DIRECTORY "$ENV{USERPROFILE}")
+else()
+    set(USER_HOME_DIRECTORY "$ENV{HOME}")
+endif()
+set(RUST_TOOLCHAIN "${USER_HOME_DIRECTORY}/.cargo/bin")
+
+### FlorisBoard ###
+
+add_library(fl_native SHARED src/lib.c)
+
+if(CMAKE_ANDROID_ARCH_ABI STREQUAL "armeabi-v7a")
+    set(ANDROID_TARGET "armv7a-linux-androideabi")
+    set(RUST_TARGET "armv7-linux-androideabi")
+elseif(CMAKE_ANDROID_ARCH_ABI STREQUAL "arm64-v8a")
+    set(ANDROID_TARGET "aarch64-linux-android")
+    set(RUST_TARGET "aarch64-linux-android")
+elseif(CMAKE_ANDROID_ARCH_ABI STREQUAL "x86")
+    set(ANDROID_TARGET "i686-linux-android")
+    set(RUST_TARGET "i686-linux-android")
+elseif(CMAKE_ANDROID_ARCH_ABI STREQUAL "x86_64")
+    set(ANDROID_TARGET "x86_64-linux-android")
+    set(RUST_TARGET "x86_64-linux-android")
+else()
+    message(FATAL_ERROR "Unsupported ABI: ${CMAKE_ANDROID_ARCH_ABI}")
+endif()
+get_filename_component(LLVM_TOOLCHAIN ${CMAKE_C_COMPILER} DIRECTORY)
+
+set(FL_NATIVE_RUST_PATH "${CMAKE_CURRENT_SOURCE_DIR}/target/${RUST_TARGET}/release/libfl_native_rust.a")
+
+add_custom_target(
+    setup_rust_target ALL
+    COMMAND ${RUST_TOOLCHAIN}/rustup target add ${RUST_TARGET}
+)
+add_custom_target(
+    fl_native_rust_build ALL
+    COMMAND ${RUST_TOOLCHAIN}/cargo rustc --release --target ${RUST_TARGET} --
+        -C linker="${LLVM_TOOLCHAIN}/${ANDROID_TARGET}${CMAKE_ANDROID_API}-clang"
+    DEPENDS setup_rust_target
+    BYPRODUCTS ${FL_NATIVE_RUST_PATH}
+    WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
+)
+
+add_dependencies(fl_native fl_native_rust_build)
+
+# TODO: check if there's a better way than allowing multiple symbol definitions
+target_link_libraries(fl_native
+    android log -Wl,--whole-archive -Wl,--allow-multiple-definition ${FL_NATIVE_RUST_PATH}
+)

lib/native/src/main/rust/Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+name = "fl_native_rust"
+version = "0.1.0"
+edition = "2021"
+
+[lib]
+name = "fl_native_rust"
+crate-type = ["staticlib"]
+
+[dependencies]
+dummy = { path = "../../../../../libnative/dummy" }
+jni = "0.21.1"

lib/native/src/main/rust/src/lib.c

@@ -0,0 +1 @@
+// DO NOT DELETE ELSE CMAKE FAILS

lib/native/src/main/rust/src/lib.rs

@@ -0,0 +1,15 @@
+use dummy;
+
+use jni::objects::JClass;
+use jni::sys::jint;
+use jni::JNIEnv;
+
+#[no_mangle]
+pub extern "system" fn Java_org_florisboard_libnative_TestKt_dummyAdd(
+    _env: JNIEnv,
+    _class: JClass,
+    a: jint,
+    b: jint,
+) -> jint {
+    dummy::addnumbers(a, b)
+}

libnative/dummy/Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "dummy"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]

libnative/dummy/src/lib.rs

@@ -0,0 +1,3 @@
+pub fn addnumbers(left: i32, right: i32) -> i32 {
+    left + right
+}

settings.gradle.kts

@@ -36,3 +36,4 @@ dependencyResolutionManagement {
 include(":app")
 include(":benchmark")
 include(":lib:kotlin")
+include(":lib:native")