2 files changed, 326 insertions, 0 deletions

diff --git a/llama.cpp/examples/llama.android/app/src/main/java/com/example/llama/MainActivity.kt b/llama.cpp/examples/llama.android/app/src/main/java/com/example/llama/MainActivity.kt
new file mode 100644
index 0000000..872ec2b
--- /dev/null
+++ b/llama.cpp/examples/llama.android/app/src/main/java/com/example/llama/MainActivity.kt
@@ -0,0 +1,275 @@
+package com.example.llama
+
+import android.net.Uri
+import android.os.Bundle
+import android.util.Log
+import android.widget.EditText
+import android.widget.TextView
+import android.widget.Toast
+import androidx.activity.addCallback
+import androidx.activity.enableEdgeToEdge
+import androidx.activity.result.contract.ActivityResultContracts
+import androidx.appcompat.app.AppCompatActivity
+import androidx.lifecycle.lifecycleScope
+import androidx.recyclerview.widget.LinearLayoutManager
+import androidx.recyclerview.widget.RecyclerView
+import com.arm.aichat.AiChat
+import com.arm.aichat.InferenceEngine
+import com.arm.aichat.gguf.GgufMetadata
+import com.arm.aichat.gguf.GgufMetadataReader
+import com.google.android.material.floatingactionbutton.FloatingActionButton
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.flow.onCompletion
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
+import java.io.File
+import java.io.FileOutputStream
+import java.io.InputStream
+import java.util.UUID
+
+class MainActivity : AppCompatActivity() {
+
+    // Android views
+    private lateinit var ggufTv: TextView
+    private lateinit var messagesRv: RecyclerView
+    private lateinit var userInputEt: EditText
+    private lateinit var userActionFab: FloatingActionButton
+
+    // Arm AI Chat inference engine
+    private lateinit var engine: InferenceEngine
+    private var generationJob: Job? = null
+
+    // Conversation states
+    private var isModelReady = false
+    private val messages = mutableListOf<Message>()
+    private val lastAssistantMsg = StringBuilder()
+    private val messageAdapter = MessageAdapter(messages)
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        enableEdgeToEdge()
+        setContentView(R.layout.activity_main)
+        // View model boilerplate and state management is out of this basic sample's scope
+        onBackPressedDispatcher.addCallback { Log.w(TAG, "Ignore back press for simplicity") }
+
+        // Find views
+        ggufTv = findViewById(R.id.gguf)
+        messagesRv = findViewById(R.id.messages)
+        messagesRv.layoutManager = LinearLayoutManager(this).apply { stackFromEnd = true }
+        messagesRv.adapter = messageAdapter
+        userInputEt = findViewById(R.id.user_input)
+        userActionFab = findViewById(R.id.fab)
+
+        // Arm AI Chat initialization
+        lifecycleScope.launch(Dispatchers.Default) {
+            engine = AiChat.getInferenceEngine(applicationContext)
+        }
+
+        // Upon CTA button tapped
+        userActionFab.setOnClickListener {
+            if (isModelReady) {
+                // If model is ready, validate input and send to engine
+                handleUserInput()
+            } else {
+                // Otherwise, prompt user to select a GGUF metadata on the device
+                getContent.launch(arrayOf("*/*"))
+            }
+        }
+    }
+
+    private val getContent = registerForActivityResult(
+        ActivityResultContracts.OpenDocument()
+    ) { uri ->
+        Log.i(TAG, "Selected file uri:\n $uri")
+        uri?.let { handleSelectedModel(it) }
+    }
+
+    /**
+     * Handles the file Uri from [getContent] result
+     */
+    private fun handleSelectedModel(uri: Uri) {
+        // Update UI states
+        userActionFab.isEnabled = false
+        userInputEt.hint = "Parsing GGUF..."
+        ggufTv.text = "Parsing metadata from selected file \n$uri"
+
+        lifecycleScope.launch(Dispatchers.IO) {
+            // Parse GGUF metadata
+            Log.i(TAG, "Parsing GGUF metadata...")
+            contentResolver.openInputStream(uri)?.use {
+                GgufMetadataReader.create().readStructuredMetadata(it)
+            }?.let { metadata ->
+                // Update UI to show GGUF metadata to user
+                Log.i(TAG, "GGUF parsed: \n$metadata")
+                withContext(Dispatchers.Main) {
+                    ggufTv.text = metadata.toString()
+                }
+
+                // Ensure the model file is available
+                val modelName = metadata.filename() + FILE_EXTENSION_GGUF
+                contentResolver.openInputStream(uri)?.use { input ->
+                    ensureModelFile(modelName, input)
+                }?.let { modelFile ->
+                    loadModel(modelName, modelFile)
+
+                    withContext(Dispatchers.Main) {
+                        isModelReady = true
+                        userInputEt.hint = "Type and send a message!"
+                        userInputEt.isEnabled = true
+                        userActionFab.setImageResource(R.drawable.outline_send_24)
+                        userActionFab.isEnabled = true
+                    }
+                }
+            }
+        }
+    }
+
+    /**
+     * Prepare the model file within app's private storage
+     */
+    private suspend fun ensureModelFile(modelName: String, input: InputStream) =
+        withContext(Dispatchers.IO) {
+            File(ensureModelsDirectory(), modelName).also { file ->
+                // Copy the file into local storage if not yet done
+                if (!file.exists()) {
+                    Log.i(TAG, "Start copying file to $modelName")
+                    withContext(Dispatchers.Main) {
+                        userInputEt.hint = "Copying file..."
+                    }
+
+                    FileOutputStream(file).use { input.copyTo(it) }
+                    Log.i(TAG, "Finished copying file to $modelName")
+                } else {
+                    Log.i(TAG, "File already exists $modelName")
+                }
+            }
+        }
+
+    /**
+     * Load the model file from the app private storage
+     */
+    private suspend fun loadModel(modelName: String, modelFile: File) =
+        withContext(Dispatchers.IO) {
+            Log.i(TAG, "Loading model $modelName")
+            withContext(Dispatchers.Main) {
+                userInputEt.hint = "Loading model..."
+            }
+            engine.loadModel(modelFile.path)
+        }
+
+    /**
+     * Validate and send the user message into [InferenceEngine]
+     */
+    private fun handleUserInput() {
+        userInputEt.text.toString().also { userMsg ->
+            if (userMsg.isEmpty()) {
+                Toast.makeText(this, "Input message is empty!", Toast.LENGTH_SHORT).show()
+            } else {
+                userInputEt.text = null
+                userInputEt.isEnabled = false
+                userActionFab.isEnabled = false
+
+                // Update message states
+                messages.add(Message(UUID.randomUUID().toString(), userMsg, true))
+                lastAssistantMsg.clear()
+                messages.add(Message(UUID.randomUUID().toString(), lastAssistantMsg.toString(), false))
+
+                generationJob = lifecycleScope.launch(Dispatchers.Default) {
+                    engine.sendUserPrompt(userMsg)
+                        .onCompletion {
+                            withContext(Dispatchers.Main) {
+                                userInputEt.isEnabled = true
+                                userActionFab.isEnabled = true
+                            }
+                        }.collect { token ->
+                            withContext(Dispatchers.Main) {
+                                val messageCount = messages.size
+                                check(messageCount > 0 && !messages[messageCount - 1].isUser)
+
+                                messages.removeAt(messageCount - 1).copy(
+                                    content = lastAssistantMsg.append(token).toString()
+                                ).let { messages.add(it) }
+
+                                messageAdapter.notifyItemChanged(messages.size - 1)
+                            }
+                        }
+                }
+            }
+        }
+    }
+
+    /**
+     * Run a benchmark with the model file
+     */
+    @Deprecated("This benchmark doesn't accurately indicate GUI performance expected by app developers")
+    private suspend fun runBenchmark(modelName: String, modelFile: File) =
+        withContext(Dispatchers.Default) {
+            Log.i(TAG, "Starts benchmarking $modelName")
+            withContext(Dispatchers.Main) {
+                userInputEt.hint = "Running benchmark..."
+            }
+            engine.bench(
+                pp=BENCH_PROMPT_PROCESSING_TOKENS,
+                tg=BENCH_TOKEN_GENERATION_TOKENS,
+                pl=BENCH_SEQUENCE,
+                nr=BENCH_REPETITION
+            ).let { result ->
+                messages.add(Message(UUID.randomUUID().toString(), result, false))
+                withContext(Dispatchers.Main) {
+                    messageAdapter.notifyItemChanged(messages.size - 1)
+                }
+            }
+        }
+
+    /**
+     * Create the `models` directory if not exist.
+     */
+    private fun ensureModelsDirectory() =
+        File(filesDir, DIRECTORY_MODELS).also {
+            if (it.exists() && !it.isDirectory) { it.delete() }
+            if (!it.exists()) { it.mkdir() }
+        }
+
+    override fun onStop() {
+        generationJob?.cancel()
+        super.onStop()
+    }
+
+    override fun onDestroy() {
+        engine.destroy()
+        super.onDestroy()
+    }
+
+    companion object {
+        private val TAG = MainActivity::class.java.simpleName
+
+        private const val DIRECTORY_MODELS = "models"
+        private const val FILE_EXTENSION_GGUF = ".gguf"
+
+        private const val BENCH_PROMPT_PROCESSING_TOKENS = 512
+        private const val BENCH_TOKEN_GENERATION_TOKENS = 128
+        private const val BENCH_SEQUENCE = 1
+        private const val BENCH_REPETITION = 3
+    }
+}
+
+fun GgufMetadata.filename() = when {
+    basic.name != null -> {
+        basic.name?.let { name ->
+            basic.sizeLabel?.let { size ->
+                "$name-$size"
+            } ?: name
+        }
+    }
+    architecture?.architecture != null -> {
+        architecture?.architecture?.let { arch ->
+            basic.uuid?.let { uuid ->
+                "$arch-$uuid"
+            } ?: "$arch-${System.currentTimeMillis()}"
+        }
+    }
+    else -> {
+        "model-${System.currentTimeMillis().toHexString()}"
+    }
+}
diff --git a/llama.cpp/examples/llama.android/app/src/main/java/com/example/llama/MessageAdapter.kt b/llama.cpp/examples/llama.android/app/src/main/java/com/example/llama/MessageAdapter.kt
new file mode 100644
index 0000000..0439f96
--- /dev/null
+++ b/llama.cpp/examples/llama.android/app/src/main/java/com/example/llama/MessageAdapter.kt
@@ -0,0 +1,51 @@
+package com.example.llama
+
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import android.widget.TextView
+import androidx.recyclerview.widget.RecyclerView
+
+data class Message(
+    val id: String,
+    val content: String,
+    val isUser: Boolean
+)
+
+class MessageAdapter(
+    private val messages: List<Message>
+) : RecyclerView.Adapter<RecyclerView.ViewHolder>() {
+
+    companion object {
+        private const val VIEW_TYPE_USER = 1
+        private const val VIEW_TYPE_ASSISTANT = 2
+    }
+
+    override fun getItemViewType(position: Int): Int {
+        return if (messages[position].isUser) VIEW_TYPE_USER else VIEW_TYPE_ASSISTANT
+    }
+
+    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
+        val layoutInflater = LayoutInflater.from(parent.context)
+        return if (viewType == VIEW_TYPE_USER) {
+            val view = layoutInflater.inflate(R.layout.item_message_user, parent, false)
+            UserMessageViewHolder(view)
+        } else {
+            val view = layoutInflater.inflate(R.layout.item_message_assistant, parent, false)
+            AssistantMessageViewHolder(view)
+        }
+    }
+
+    override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
+        val message = messages[position]
+        if (holder is UserMessageViewHolder || holder is AssistantMessageViewHolder) {
+            val textView = holder.itemView.findViewById<TextView>(R.id.msg_content)
+            textView.text = message.content
+        }
+    }
+
+    override fun getItemCount(): Int = messages.size
+
+    class UserMessageViewHolder(view: View) : RecyclerView.ViewHolder(view)
+    class AssistantMessageViewHolder(view: View) : RecyclerView.ViewHolder(view)
+}