feat: add mobile app build scaffolding

.github/workflows/mobile-apps.yml

@@ -0,0 +1,43 @@
+name: Mobile Apps
+
+on:
+  pull_request:
+    paths:
+      - ".github/workflows/mobile-apps.yml"
+      - "barretenberg/mobile-app/**"
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  android:
+    name: Android APK
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: "17"
+      - uses: gradle/actions/setup-gradle@v4
+        with:
+          gradle-version: "8.10.2"
+      - run: ./barretenberg/mobile-app/scripts/build-android.sh
+      - uses: actions/upload-artifact@v4
+        with:
+          name: bb-mobile-bench-android-debug-apk
+          path: barretenberg/mobile-app/android/app/build/outputs/apk/debug/app-debug.apk
+          if-no-files-found: error
+
+  ios:
+    name: iOS Device App
+    runs-on: macos-15
+    steps:
+      - uses: actions/checkout@v4
+      - run: ./barretenberg/mobile-app/scripts/build-ios.sh
+      - uses: actions/upload-artifact@v4
+        with:
+          name: bb-mobile-bench-ios-unsigned-ipa
+          path: barretenberg/mobile-app/ios/build/BBMobileBench.ipa
+          if-no-files-found: error

Makefile

@@ -47,7 +47,7 @@ endef
 # PHONY TARGETS - List every target that has a file/dir of the same name.
 #==============================================================================
 
-.PHONY: noir barretenberg noir-projects l1-contracts release-image boxes playground docs aztec-up spartan
+.PHONY: noir barretenberg noir-projects l1-contracts release-image boxes playground docs aztec-up spartan bb-mobile-app-android bb-mobile-app-ios bb-mobile-apps
 
 #==============================================================================
 # BOOTSTRAP TARGETS
@@ -210,6 +210,14 @@ bb-cpp-release-dir: bb-cpp-native bb-cpp-cross
 
 bb-cpp-full: bb-cpp bb-cpp-gcc bb-cpp-fuzzing bb-cpp-asan bb-cpp-smt bb-cpp-cross-arm64-macos bb-cpp-cross-arm64-ios bb-cpp-cross-arm64-android
 
+bb-mobile-app-android:
+	$(call run_command,$@,$(ROOT)/barretenberg/mobile-app,bash scripts/build-android.sh)
+
+bb-mobile-app-ios:
+	$(call run_command,$@,$(ROOT)/barretenberg/mobile-app,bash scripts/build-ios.sh)
+
+bb-mobile-apps: bb-mobile-app-android bb-mobile-app-ios
+
 # BB TypeScript - TypeScript bindings
 bb-ts: bb-cpp-wasm bb-cpp-wasm-threads bb-cpp-native
 	$(call build,$@,barretenberg/ts)

barretenberg/mobile-app/.gitignore

@@ -0,0 +1,5 @@
+android/.gradle/
+android/build/
+android/app/build/
+ios/build/
+ios/DerivedData/

barretenberg/mobile-app/README.md

@@ -0,0 +1,42 @@
+# Barretenberg Mobile App
+
+This directory contains the first native mobile app shells for running
+barretenberg on real phones. The apps share a small C++ bridge under
+`shared/` so Android and iOS exercise the same native entry point before the
+benchmark path is wired into `libbb-external.a`.
+
+The current CI contract is intentionally small:
+
+- Android builds a debug APK with Gradle and the Android NDK.
+- iOS builds an unsigned device app/IPA with Xcode and code signing disabled.
+
+The barretenberg static libraries already have root Makefile targets:
+
+```bash
+make bb-cpp-cross-arm64-ios
+make bb-cpp-cross-arm64-ios-sim
+make bb-cpp-cross-arm64-android
+make bb-cpp-cross-x86_64-android
+```
+
+The app shells are separate so CI can prove the mobile projects themselves are
+healthy without forcing every pull request to rebuild the heavy proving
+archives.
+
+## Local Builds
+
+Android:
+
+```bash
+barretenberg/mobile-app/scripts/build-android.sh
+```
+
+iOS, on macOS with Xcode:
+
+```bash
+barretenberg/mobile-app/scripts/build-ios.sh
+```
+
+The default iOS output is `barretenberg/mobile-app/ios/build/BBMobileBench.ipa`.
+It is unsigned and intended to prove the app target builds in CI. Real
+BrowserStack App Automate device runs still need a properly signed `.ipa`.

barretenberg/mobile-app/android/app/build.gradle.kts

@@ -0,0 +1,33 @@
+plugins {
+    id("com.android.application")
+}
+
+android {
+    namespace = "com.aztec.barretenberg.mobilebench"
+    compileSdk = 35
+
+    defaultConfig {
+        applicationId = namespace
+        minSdk = 26
+        targetSdk = 35
+        versionCode = 1
+        versionName = "0.1"
+
+        externalNativeBuild {
+            cmake {
+                cppFlags += "-std=c++20"
+            }
+        }
+
+        ndk {
+            abiFilters += listOf("arm64-v8a", "x86_64")
+        }
+    }
+
+    externalNativeBuild {
+        cmake {
+            path = file("src/main/cpp/CMakeLists.txt")
+            version = "3.22.1"
+        }
+    }
+}

barretenberg/mobile-app/android/app/src/main/AndroidManifest.xml

@@ -0,0 +1,17 @@
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+    <application
+        android:allowBackup="false"
+        android:extractNativeLibs="true"
+        android:label="BB Mobile Bench"
+        android:supportsRtl="true"
+        android:theme="@style/AppTheme">
+        <activity
+            android:name=".MainActivity"
+            android:exported="true">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+    </application>
+</manifest>

barretenberg/mobile-app/android/app/src/main/cpp/CMakeLists.txt

@@ -0,0 +1,18 @@
+cmake_minimum_required(VERSION 3.22.1)
+
+project(bbmobilebench LANGUAGES CXX)
+
+add_library(
+    bbmobilebench
+    SHARED
+    mobile_bench_jni.cpp
+    ../../../../../shared/src/bb_mobile.cpp
+)
+
+target_include_directories(
+    bbmobilebench
+    PRIVATE
+    ../../../../../shared/include
+)
+
+target_compile_features(bbmobilebench PRIVATE cxx_std_20)

barretenberg/mobile-app/android/app/src/main/cpp/mobile_bench_jni.cpp

@@ -0,0 +1,15 @@
+#include "bb_mobile.h"
+
+#include <jni.h>
+
+extern "C" JNIEXPORT jstring JNICALL
+Java_com_aztec_barretenberg_mobilebench_MainActivity_nativeStatus(JNIEnv* env, jclass)
+{
+    return env->NewStringUTF(bb_mobile_status());
+}
+
+extern "C" JNIEXPORT jint JNICALL
+Java_com_aztec_barretenberg_mobilebench_MainActivity_nativeAbiVersion(JNIEnv*, jclass)
+{
+    return bb_mobile_abi_version();
+}

barretenberg/mobile-app/android/app/src/main/java/com/aztec/barretenberg/mobilebench/MainActivity.java

@@ -0,0 +1,38 @@
+package com.aztec.barretenberg.mobilebench;
+
+import android.app.Activity;
+import android.os.Bundle;
+import android.view.Gravity;
+import android.widget.LinearLayout;
+import android.widget.TextView;
+
+public final class MainActivity extends Activity {
+    static {
+        System.loadLibrary("bbmobilebench");
+    }
+
+    private static native String nativeStatus();
+    private static native int nativeAbiVersion();
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+
+        LinearLayout root = new LinearLayout(this);
+        root.setGravity(Gravity.CENTER);
+        root.setOrientation(LinearLayout.VERTICAL);
+        root.setPadding(48, 48, 48, 48);
+
+        TextView title = new TextView(this);
+        title.setText("Barretenberg Mobile Bench");
+        title.setTextSize(24);
+
+        TextView status = new TextView(this);
+        status.setText(nativeStatus() + " (ABI " + nativeAbiVersion() + ")");
+        status.setTextSize(16);
+
+        root.addView(title);
+        root.addView(status);
+        setContentView(root);
+    }
+}

barretenberg/mobile-app/android/app/src/main/res/values/styles.xml

@@ -0,0 +1,7 @@
+<resources>
+    <style name="AppTheme" parent="android:style/Theme.Material.Light.NoActionBar">
+        <item name="android:fontFamily">sans</item>
+        <item name="android:windowLightStatusBar">true</item>
+        <item name="android:colorAccent">#2F6FED</item>
+    </style>
+</resources>

barretenberg/mobile-app/android/build.gradle.kts

@@ -0,0 +1,3 @@
+plugins {
+    id("com.android.application") version "8.8.2" apply false
+}

barretenberg/mobile-app/android/gradle.properties

@@ -0,0 +1,2 @@
+android.useAndroidX=false
+org.gradle.jvmargs=-Xmx2g -Dfile.encoding=UTF-8

barretenberg/mobile-app/android/settings.gradle.kts

@@ -0,0 +1,18 @@
+pluginManagement {
+    repositories {
+        google()
+        mavenCentral()
+        gradlePluginPortal()
+    }
+}
+
+dependencyResolutionManagement {
+    repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
+    repositories {
+        google()
+        mavenCentral()
+    }
+}
+
+rootProject.name = "BarretenbergMobileBench"
+include(":app")