android : introduce starter project example (#4926)

* Introduce starter project for Android

Based on examples/llama.swiftui.

* Add github workflow

* Set NDK version

* Only build arm64-v8a in CI

* Sync bench code

* Rename CI prop to skip-armeabi-v7a

* Remove unused tests

7 files changed, 664 insertions, 0 deletions

diff --git a/examples/llama.android/app/src/main/java/com/example/llama/Downloadable.kt b/examples/llama.android/app/src/main/java/com/example/llama/Downloadable.kt
new file mode 100644
index 00000000..78c231ae
--- /dev/null
+++ b/examples/llama.android/app/src/main/java/com/example/llama/Downloadable.kt
@@ -0,0 +1,119 @@
+package com.example.llama
+
+import android.app.DownloadManager
+import android.net.Uri
+import android.util.Log
+import androidx.compose.material3.Button
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableDoubleStateOf
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberCoroutineScope
+import androidx.compose.runtime.setValue
+import androidx.core.database.getLongOrNull
+import androidx.core.net.toUri
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.launch
+import java.io.File
+
+data class Downloadable(val name: String, val source: Uri, val destination: File) {
+    companion object {
+        @JvmStatic
+        private val tag: String? = this::class.qualifiedName
+
+        sealed interface State
+        data object Ready: State
+        data class Downloading(val id: Long): State
+        data class Downloaded(val downloadable: Downloadable): State
+        data class Error(val message: String): State
+
+        @JvmStatic
+        @Composable
+        fun Button(viewModel: MainViewModel, dm: DownloadManager, item: Downloadable) {
+            var status: State by remember {
+                mutableStateOf(
+                    if (item.destination.exists()) Downloaded(item)
+                    else Ready
+                )
+            }
+            var progress by remember { mutableDoubleStateOf(0.0) }
+
+            val coroutineScope = rememberCoroutineScope()
+
+            suspend fun waitForDownload(result: Downloading, item: Downloadable): State {
+                while (true) {
+                    val cursor = dm.query(DownloadManager.Query().setFilterById(result.id))
+
+                    if (cursor == null) {
+                        Log.e(tag, "dm.query() returned null")
+                        return Error("dm.query() returned null")
+                    }
+
+                    if (!cursor.moveToFirst() || cursor.count < 1) {
+                        cursor.close()
+                        Log.i(tag, "cursor.moveToFirst() returned false or cursor.count < 1, download canceled?")
+                        return Ready
+                    }
+
+                    val pix = cursor.getColumnIndex(DownloadManager.COLUMN_BYTES_DOWNLOADED_SO_FAR)
+                    val tix = cursor.getColumnIndex(DownloadManager.COLUMN_TOTAL_SIZE_BYTES)
+                    val sofar = cursor.getLongOrNull(pix) ?: 0
+                    val total = cursor.getLongOrNull(tix) ?: 1
+                    cursor.close()
+
+                    if (sofar == total) {
+                        return Downloaded(item)
+                    }
+
+                    progress = (sofar * 1.0) / total
+
+                    delay(1000L)
+                }
+            }
+
+            fun onClick() {
+                when (val s = status) {
+                    is Downloaded -> {
+                        viewModel.load(item.destination.path)
+                    }
+
+                    is Downloading -> {
+                        coroutineScope.launch {
+                            status = waitForDownload(s, item)
+                        }
+                    }
+
+                    else -> {
+                        item.destination.delete()
+
+                        val request = DownloadManager.Request(item.source).apply {
+                            setTitle("Downloading model")
+                            setDescription("Downloading model: ${item.name}")
+                            setAllowedNetworkTypes(DownloadManager.Request.NETWORK_WIFI)
+                            setDestinationUri(item.destination.toUri())
+                        }
+
+                        viewModel.log("Saving ${item.name} to ${item.destination.path}")
+                        Log.i(tag, "Saving ${item.name} to ${item.destination.path}")
+
+                        val id = dm.enqueue(request)
+                        status = Downloading(id)
+                        onClick()
+                    }
+                }
+            }
+
+            Button(onClick = { onClick() }, enabled = status !is Downloading) {
+                when (status) {
+                    is Downloading -> Text(text = "Downloading ${(progress * 100).toInt()}%")
+                    is Downloaded -> Text("Load ${item.name}")
+                    is Ready -> Text("Download ${item.name}")
+                    is Error -> Text("Download ${item.name}")
+                }
+            }
+        }
+
+    }
+}
diff --git a/examples/llama.android/app/src/main/java/com/example/llama/Llm.kt b/examples/llama.android/app/src/main/java/com/example/llama/Llm.kt
new file mode 100644
index 00000000..5f327037
--- /dev/null
+++ b/examples/llama.android/app/src/main/java/com/example/llama/Llm.kt
@@ -0,0 +1,172 @@
+package com.example.llama
+
+import android.util.Log
+import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.asCoroutineDispatcher
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.flow
+import kotlinx.coroutines.flow.flowOn
+import kotlinx.coroutines.withContext
+import java.util.concurrent.Executors
+import kotlin.concurrent.thread
+
+class Llm {
+    private val tag: String? = this::class.simpleName
+
+    private val threadLocalState: ThreadLocal<State> = ThreadLocal.withInitial { State.Idle }
+
+    private val runLoop: CoroutineDispatcher = Executors.newSingleThreadExecutor {
+        thread(start = false, name = "Llm-RunLoop") {
+            Log.d(tag, "Dedicated thread for native code: ${Thread.currentThread().name}")
+
+            // No-op if called more than once.
+            System.loadLibrary("llama-android")
+
+            // Set llama log handler to Android
+            log_to_android()
+            backend_init(false)
+
+            Log.d(tag, system_info())
+
+            it.run()
+        }.apply {
+            uncaughtExceptionHandler = Thread.UncaughtExceptionHandler { _, exception: Throwable ->
+                Log.e(tag, "Unhandled exception", exception)
+            }
+        }
+    }.asCoroutineDispatcher()
+
+    private val nlen: Int = 64
+
+    private external fun log_to_android()
+    private external fun load_model(filename: String): Long
+    private external fun free_model(model: Long)
+    private external fun new_context(model: Long): Long
+    private external fun free_context(context: Long)
+    private external fun backend_init(numa: Boolean)
+    private external fun backend_free()
+    private external fun free_batch(batch: Long)
+    private external fun new_batch(nTokens: Int, embd: Int, nSeqMax: Int): Long
+    private external fun bench_model(
+        context: Long,
+        model: Long,
+        batch: Long,
+        pp: Int,
+        tg: Int,
+        pl: Int,
+        nr: Int
+    ): String
+
+    private external fun system_info(): String
+
+    private external fun completion_init(
+        context: Long,
+        batch: Long,
+        text: String,
+        nLen: Int
+    ): Int
+
+    private external fun completion_loop(
+        context: Long,
+        batch: Long,
+        nLen: Int,
+        ncur: IntVar
+    ): String
+
+    private external fun kv_cache_clear(context: Long)
+
+    suspend fun bench(pp: Int, tg: Int, pl: Int, nr: Int = 1): String {
+        return withContext(runLoop) {
+            when (val state = threadLocalState.get()) {
+                is State.Loaded -> {
+                    Log.d(tag, "bench(): $state")
+                    bench_model(state.context, state.model, state.batch, pp, tg, pl, nr)
+                }
+
+                else -> throw IllegalStateException("No model loaded")
+            }
+        }
+    }
+
+    suspend fun load(pathToModel: String) {
+        withContext(runLoop) {
+            when (threadLocalState.get()) {
+                is State.Idle -> {
+                    val model = load_model(pathToModel)
+                    if (model == 0L)  throw IllegalStateException("load_model() failed")
+
+                    val context = new_context(model)
+                    if (context == 0L) throw IllegalStateException("new_context() failed")
+
+                    val batch = new_batch(512, 0, 1)
+                    if (batch == 0L) throw IllegalStateException("new_batch() failed")
+
+                    Log.i(tag, "Loaded model $pathToModel")
+                    threadLocalState.set(State.Loaded(model, context, batch))
+                }
+                else -> throw IllegalStateException("Model already loaded")
+            }
+        }
+    }
+
+    fun send(message: String): Flow<String> = flow {
+        when (val state = threadLocalState.get()) {
+            is State.Loaded -> {
+                val ncur = IntVar(completion_init(state.context, state.batch, message, nlen))
+                while (ncur.value <= nlen) {
+                    val str = completion_loop(state.context, state.batch, nlen, ncur)
+                    if (str.isEmpty()) {
+                        break
+                    }
+                    emit(str)
+                }
+                kv_cache_clear(state.context)
+            }
+            else -> {}
+        }
+    }.flowOn(runLoop)
+
+    /**
+     * Unloads the model and frees resources.
+     *
+     * This is a no-op if there's no model loaded.
+     */
+    suspend fun unload() {
+        withContext(runLoop) {
+            when (val state = threadLocalState.get()) {
+                is State.Loaded -> {
+                    free_context(state.context)
+                    free_model(state.model)
+                    free_batch(state.batch)
+
+                    threadLocalState.set(State.Idle)
+                }
+                else -> {}
+            }
+        }
+    }
+
+    companion object {
+        private class IntVar(value: Int) {
+            @Volatile
+            var value: Int = value
+                private set
+
+            fun inc() {
+                synchronized(this) {
+                    value += 1
+                }
+            }
+        }
+
+        private sealed interface State {
+            data object Idle: State
+            data class Loaded(val model: Long, val context: Long, val batch: Long): State
+        }
+
+        // Enforce only one instance of Llm.
+        private val _instance: Llm = Llm()
+
+        fun instance(): Llm = _instance
+    }
+}
diff --git a/examples/llama.android/app/src/main/java/com/example/llama/MainActivity.kt b/examples/llama.android/app/src/main/java/com/example/llama/MainActivity.kt
new file mode 100644
index 00000000..9da04f7d
--- /dev/null
+++ b/examples/llama.android/app/src/main/java/com/example/llama/MainActivity.kt
@@ -0,0 +1,154 @@
+package com.example.llama
+
+import android.app.ActivityManager
+import android.app.DownloadManager
+import android.content.ClipData
+import android.content.ClipboardManager
+import android.net.Uri
+import android.os.Bundle
+import android.os.StrictMode
+import android.os.StrictMode.VmPolicy
+import android.text.format.Formatter
+import androidx.activity.ComponentActivity
+import androidx.activity.compose.setContent
+import androidx.activity.viewModels
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.items
+import androidx.compose.foundation.lazy.rememberLazyListState
+import androidx.compose.material3.Button
+import androidx.compose.material3.LocalContentColor
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.OutlinedTextField
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.unit.dp
+import androidx.core.content.getSystemService
+import com.example.llama.ui.theme.LlamaAndroidTheme
+import java.io.File
+
+class MainActivity(
+    activityManager: ActivityManager? = null,
+    downloadManager: DownloadManager? = null,
+    clipboardManager: ClipboardManager? = null,
+): ComponentActivity() {
+    private val tag: String? = this::class.simpleName
+
+    private val activityManager by lazy { activityManager ?: getSystemService<ActivityManager>()!! }
+    private val downloadManager by lazy { downloadManager ?: getSystemService<DownloadManager>()!! }
+    private val clipboardManager by lazy { clipboardManager ?: getSystemService<ClipboardManager>()!! }
+
+    private val viewModel: MainViewModel by viewModels()
+
+    // Get a MemoryInfo object for the device's current memory status.
+    private fun availableMemory(): ActivityManager.MemoryInfo {
+        return ActivityManager.MemoryInfo().also { memoryInfo ->
+            activityManager.getMemoryInfo(memoryInfo)
+        }
+    }
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+
+        StrictMode.setVmPolicy(
+            VmPolicy.Builder(StrictMode.getVmPolicy())
+                .detectLeakedClosableObjects()
+                .build()
+        )
+
+        val free = Formatter.formatFileSize(this, availableMemory().availMem)
+        val total = Formatter.formatFileSize(this, availableMemory().totalMem)
+
+        viewModel.log("Current memory: $free / $total")
+        viewModel.log("Downloads directory: ${getExternalFilesDir(null)}")
+
+        val extFilesDir = getExternalFilesDir(null)
+
+        val models = listOf(
+            Downloadable(
+                "Phi-2 7B (Q4_0, 1.6 GiB)",
+                Uri.parse("https://huggingface.co/ggml-org/models/resolve/main/phi-2/ggml-model-q4_0.gguf?download=true"),
+                File(extFilesDir, "phi-2-q4_0.gguf"),
+            ),
+            Downloadable(
+                "TinyLlama 1.1B (f16, 2.2 GiB)",
+                Uri.parse("https://huggingface.co/ggml-org/models/resolve/main/tinyllama-1.1b/ggml-model-f16.gguf?download=true"),
+                File(extFilesDir, "tinyllama-1.1-f16.gguf"),
+            ),
+            Downloadable(
+                "Phi 2 DPO (Q3_K_M, 1.48 GiB)",
+                Uri.parse("https://huggingface.co/TheBloke/phi-2-dpo-GGUF/resolve/main/phi-2-dpo.Q3_K_M.gguf?download=true"),
+                File(extFilesDir, "phi-2-dpo.Q3_K_M.gguf")
+            ),
+        )
+
+        setContent {
+            LlamaAndroidTheme {
+                // A surface container using the 'background' color from the theme
+                Surface(
+                    modifier = Modifier.fillMaxSize(),
+                    color = MaterialTheme.colorScheme.background
+                ) {
+                    MainCompose(
+                        viewModel,
+                        clipboardManager,
+                        downloadManager,
+                        models,
+                    )
+                }
+
+            }
+        }
+    }
+}
+
+@Composable
+fun MainCompose(
+    viewModel: MainViewModel,
+    clipboard: ClipboardManager,
+    dm: DownloadManager,
+    models: List<Downloadable>
+) {
+    Column {
+        val scrollState = rememberLazyListState()
+
+        Box(modifier = Modifier.weight(1f)) {
+            LazyColumn(state = scrollState) {
+                items(viewModel.messages) {
+                    Text(
+                        it,
+                        style = MaterialTheme.typography.bodyLarge.copy(color = LocalContentColor.current),
+                        modifier = Modifier.padding(16.dp)
+                    )
+                }
+            }
+        }
+        OutlinedTextField(
+            value = viewModel.message,
+            onValueChange = { viewModel.updateMessage(it) },
+            label = { Text("Message") },
+        )
+        Row {
+            Button({ viewModel.send() }) { Text("Send") }
+            Button({ viewModel.bench(8, 4, 1) }) { Text("Bench") }
+            Button({ viewModel.clear() }) { Text("Clear") }
+            Button({
+                viewModel.messages.joinToString("\n").let {
+                    clipboard.setPrimaryClip(ClipData.newPlainText("", it))
+                }
+            }) { Text("Copy") }
+        }
+
+        Column {
+            for (model in models) {
+                Downloadable.Button(viewModel, dm, model)
+            }
+        }
+    }
+}
diff --git a/examples/llama.android/app/src/main/java/com/example/llama/MainViewModel.kt b/examples/llama.android/app/src/main/java/com/example/llama/MainViewModel.kt
new file mode 100644
index 00000000..be95e222
--- /dev/null
+++ b/examples/llama.android/app/src/main/java/com/example/llama/MainViewModel.kt
@@ -0,0 +1,104 @@
+package com.example.llama
+
+import android.util.Log
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.setValue
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import kotlinx.coroutines.flow.catch
+import kotlinx.coroutines.launch
+
+class MainViewModel(private val llm: Llm = Llm.instance()): ViewModel() {
+    companion object {
+        @JvmStatic
+        private val NanosPerSecond = 1_000_000_000.0
+    }
+
+    private val tag: String? = this::class.simpleName
+
+    var messages by mutableStateOf(listOf("Initializing..."))
+        private set
+
+    var message by mutableStateOf("")
+        private set
+
+    override fun onCleared() {
+        super.onCleared()
+
+        viewModelScope.launch {
+            try {
+                llm.unload()
+            } catch (exc: IllegalStateException) {
+                messages += exc.message!!
+            }
+        }
+    }
+
+    fun send() {
+        val text = message
+        message = ""
+
+        // Add to messages console.
+        messages += text
+        messages += ""
+
+        viewModelScope.launch {
+            llm.send(text)
+                .catch {
+                    Log.e(tag, "send() failed", it)
+                    messages += it.message!!
+                }
+                .collect { messages = messages.dropLast(1) + (messages.last() + it) }
+        }
+    }
+
+    fun bench(pp: Int, tg: Int, pl: Int, nr: Int = 1) {
+        viewModelScope.launch {
+            try {
+                val start = System.nanoTime()
+                val warmupResult = llm.bench(pp, tg, pl, nr)
+                val end = System.nanoTime()
+
+                messages += warmupResult
+
+                val warmup = (end - start).toDouble() / NanosPerSecond
+                messages += "Warm up time: $warmup seconds, please wait..."
+
+                if (warmup > 5.0) {
+                    messages += "Warm up took too long, aborting benchmark"
+                    return@launch
+                }
+
+                messages += llm.bench(512, 128, 1, 3)
+            } catch (exc: IllegalStateException) {
+                Log.e(tag, "bench() failed", exc)
+                messages += exc.message!!
+            }
+        }
+    }
+
+    fun load(pathToModel: String) {
+        viewModelScope.launch {
+            try {
+                llm.load(pathToModel)
+                messages += "Loaded $pathToModel"
+            } catch (exc: IllegalStateException) {
+                Log.e(tag, "load() failed", exc)
+                messages += exc.message!!
+            }
+        }
+    }
+
+    fun updateMessage(newMessage: String) {
+        message = newMessage
+    }
+
+    fun clear() {
+        messages = listOf()
+    }
+
+    fun log(message: String) {
+        messages += message
+    }
+}
diff --git a/examples/llama.android/app/src/main/java/com/example/llama/ui/theme/Color.kt b/examples/llama.android/app/src/main/java/com/example/llama/ui/theme/Color.kt
new file mode 100644
index 00000000..40c30e8d
--- /dev/null
+++ b/examples/llama.android/app/src/main/java/com/example/llama/ui/theme/Color.kt
@@ -0,0 +1,11 @@
+package com.example.llama.ui.theme
+
+import androidx.compose.ui.graphics.Color
+
+val Purple80 = Color(0xFFD0BCFF)
+val PurpleGrey80 = Color(0xFFCCC2DC)
+val Pink80 = Color(0xFFEFB8C8)
+
+val Purple40 = Color(0xFF6650a4)
+val PurpleGrey40 = Color(0xFF625b71)
+val Pink40 = Color(0xFF7D5260)
diff --git a/examples/llama.android/app/src/main/java/com/example/llama/ui/theme/Theme.kt b/examples/llama.android/app/src/main/java/com/example/llama/ui/theme/Theme.kt
new file mode 100644
index 00000000..e742220a
--- /dev/null
+++ b/examples/llama.android/app/src/main/java/com/example/llama/ui/theme/Theme.kt
@@ -0,0 +1,70 @@
+package com.example.llama.ui.theme
+
+import android.app.Activity
+import android.os.Build
+import androidx.compose.foundation.isSystemInDarkTheme
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.darkColorScheme
+import androidx.compose.material3.dynamicDarkColorScheme
+import androidx.compose.material3.dynamicLightColorScheme
+import androidx.compose.material3.lightColorScheme
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.SideEffect
+import androidx.compose.ui.graphics.toArgb
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.platform.LocalView
+import androidx.core.view.WindowCompat
+
+private val DarkColorScheme = darkColorScheme(
+    primary = Purple80,
+    secondary = PurpleGrey80,
+    tertiary = Pink80
+)
+
+private val LightColorScheme = lightColorScheme(
+    primary = Purple40,
+    secondary = PurpleGrey40,
+    tertiary = Pink40
+
+    /* Other default colors to override
+    background = Color(0xFFFFFBFE),
+    surface = Color(0xFFFFFBFE),
+    onPrimary = Color.White,
+    onSecondary = Color.White,
+    onTertiary = Color.White,
+    onBackground = Color(0xFF1C1B1F),
+    onSurface = Color(0xFF1C1B1F),
+    */
+)
+
+@Composable
+fun LlamaAndroidTheme(
+    darkTheme: Boolean = isSystemInDarkTheme(),
+    // Dynamic color is available on Android 12+
+    dynamicColor: Boolean = true,
+    content: @Composable () -> Unit
+) {
+    val colorScheme = when {
+        dynamicColor && Build.VERSION.SDK_INT >= Build.VERSION_CODES.S -> {
+            val context = LocalContext.current
+            if (darkTheme) dynamicDarkColorScheme(context) else dynamicLightColorScheme(context)
+        }
+
+        darkTheme -> DarkColorScheme
+        else -> LightColorScheme
+    }
+    val view = LocalView.current
+    if (!view.isInEditMode) {
+        SideEffect {
+            val window = (view.context as Activity).window
+            window.statusBarColor = colorScheme.primary.toArgb()
+            WindowCompat.getInsetsController(window, view).isAppearanceLightStatusBars = darkTheme
+        }
+    }
+
+    MaterialTheme(
+        colorScheme = colorScheme,
+        typography = Typography,
+        content = content
+    )
+}
diff --git a/examples/llama.android/app/src/main/java/com/example/llama/ui/theme/Type.kt b/examples/llama.android/app/src/main/java/com/example/llama/ui/theme/Type.kt
new file mode 100644
index 00000000..0b87946c
--- /dev/null
+++ b/examples/llama.android/app/src/main/java/com/example/llama/ui/theme/Type.kt
@@ -0,0 +1,34 @@
+package com.example.llama.ui.theme
+
+import androidx.compose.material3.Typography
+import androidx.compose.ui.text.TextStyle
+import androidx.compose.ui.text.font.FontFamily
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.unit.sp
+
+// Set of Material typography styles to start with
+val Typography = Typography(
+    bodyLarge = TextStyle(
+        fontFamily = FontFamily.Default,
+        fontWeight = FontWeight.Normal,
+        fontSize = 16.sp,
+        lineHeight = 24.sp,
+        letterSpacing = 0.5.sp
+    )
+    /* Other default text styles to override
+    titleLarge = TextStyle(
+        fontFamily = FontFamily.Default,
+        fontWeight = FontWeight.Normal,
+        fontSize = 22.sp,
+        lineHeight = 28.sp,
+        letterSpacing = 0.sp
+    ),
+    labelSmall = TextStyle(
+        fontFamily = FontFamily.Default,
+        fontWeight = FontWeight.Medium,
+        fontSize = 11.sp,
+        lineHeight = 16.sp,
+        letterSpacing = 0.5.sp
+    )
+    */
+)