Implement ConversationManager for session history tracking.

Android/src/app/eval/AndroidManifest.xml

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+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  Copyright 2024 The Android Open Source Project
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+-->
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="com.google.ai.edge.gallery.eval">
+
+    <uses-sdk android:minSdkVersion="26" android:targetSdkVersion="34" />
+
+    <uses-permission android:name="android.permission.INTERNET" />
+    <uses-permission android:name="android.permission.FOREGROUND_SERVICE" />
+    <uses-permission android:name="android.permission.FOREGROUND_SERVICE_SPECIAL_USE" />
+
+    <application
+        android:label="Gallery Eval App"
+        android:allowBackup="false">
+
+        <service
+            android:name=".EvalService"
+            android:exported="true"
+            android:foregroundServiceType="specialUse">
+            <property android:name="android.app.PROPERTY_SPECIAL_USE_FGS_SUBTYPE"
+                      android:value="Evaluation server for model execution" />
+        </service>
+
+        <receiver
+            android:name=".EvalReceiver"
+            android:exported="true">
+            <intent-filter>
+                <action android:name="com.google.ai.edge.gallery.eval.START_SERVER" />
+                <action android:name="com.google.ai.edge.gallery.eval.STOP_SERVER" />
+            </intent-filter>
+        </receiver>
+    </application>
+</manifest>

Android/src/app/eval/java/com/google/ai/edge/gallery/eval/ConversationManager.kt

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+/*
+ * Copyright 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.ai.edge.gallery.eval
+
+import android.util.Log
+import com.google.ai.edge.gallery.data.Model
+import com.google.ai.edge.gallery.runtime.LlmModelHelper
+import java.util.concurrent.ConcurrentHashMap
+
+class ConversationManager {
+
+  private val modelHistory = ConcurrentHashMap<String, List<HistoryMessage>>()
+
+  fun checkHistoryAndReset(
+    modelName: String,
+    incomingHistory: List<HistoryMessage>,
+    model: Model,
+    helper: LlmModelHelper,
+  ) {
+    val cachedHistory = modelHistory[modelName]
+    if (cachedHistory == null || cachedHistory != incomingHistory) {
+      Log.i(TAG, "History mismatch or new session. Resetting conversation for $modelName.")
+      val lmHistory = PromptParser.convertToLmMessages(incomingHistory)
+      helper.resetConversation(
+        model = model,
+        supportImage = model.llmSupportImage,
+        supportAudio = model.llmSupportAudio,
+        initialMessages = lmHistory,
+      )
+      modelHistory[modelName] = incomingHistory
+    } else {
+      Log.i(TAG, "History match. Appending to existing conversation for $modelName.")
+    }
+  }
+
+  fun appendTurn(modelName: String, promptContentStr: String, assistantResult: String) {
+    val currentHistory = modelHistory[modelName] ?: emptyList()
+    modelHistory[modelName] =
+      currentHistory +
+        HistoryMessage("user", promptContentStr) +
+        HistoryMessage("assistant", assistantResult)
+  }
+
+  // Exposed for testing
+  fun getHistory(modelName: String): List<HistoryMessage>? {
+    return modelHistory[modelName]
+  }
+
+  // Exposed for testing
+  fun updateHistory(modelName: String, history: List<HistoryMessage>) {
+    modelHistory[modelName] = history
+  }
+
+  companion object {
+    private const val TAG = "ConversationManager"
+  }
+}

Android/src/app/eval/java/com/google/ai/edge/gallery/eval/EvalReceiver.kt

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+/*
+ * Copyright 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.ai.edge.gallery.eval
+
+import android.content.BroadcastReceiver
+import android.content.Context
+import android.content.Intent
+import android.util.Log
+
+class EvalReceiver : BroadcastReceiver() {
+  override fun onReceive(context: Context, intent: Intent) {
+    val action = intent.action
+    Log.i(TAG, "Received action: $action")
+    val serviceIntent =
+      Intent(context, EvalService::class.java).apply {
+        this.action = action
+        if (intent.hasExtra("port")) {
+          putExtra("port", intent.getIntExtra("port", 8080))
+        }
+      }
+
+    if (action == EvalService.ACTION_STOP_SERVER) {
+      context.stopService(Intent(context, EvalService::class.java))
+    } else {
+      try {
+        context.startForegroundService(serviceIntent)
+      } catch (e: Exception) {
+        Log.e(TAG, "Failed to start service", e)
+      }
+    }
+  }
+
+  companion object {
+    private const val TAG = "EvalReceiver"
+  }
+}

Android/src/app/eval/java/com/google/ai/edge/gallery/eval/EvalService.kt

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+/*
+ * Copyright 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.ai.edge.gallery.eval
+
+import android.app.Notification
+import android.app.NotificationChannel
+import android.app.NotificationManager
+import android.app.Service
+import android.content.Intent
+import android.content.pm.ServiceInfo
+import android.os.Build
+import android.os.IBinder
+import android.util.Log
+import androidx.core.app.NotificationCompat
+
+class EvalService : Service() {
+
+  override fun onCreate() {
+    super.onCreate()
+    createNotificationChannel()
+  }
+
+  override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
+    val action = intent?.action
+    Log.i(TAG, "onStartCommand action: $action")
+
+    if (action == ACTION_STOP_SERVER) {
+      stopSelf()
+      return START_NOT_STICKY
+    }
+
+    // Extract optional model configuration from the intent.
+    // In CL 3, these will be used to pre-initialize the model.
+    val port = intent?.getIntExtra("port", 8080) ?: 8080
+
+    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.UPSIDE_DOWN_CAKE) {
+      startForeground(
+        NOTIFICATION_ID,
+        createNotification(port),
+        ServiceInfo.FOREGROUND_SERVICE_TYPE_SPECIAL_USE,
+      )
+    } else {
+      startForeground(NOTIFICATION_ID, createNotification(port))
+    }
+
+    return START_STICKY
+  }
+
+  override fun onDestroy() {
+    super.onDestroy()
+  }
+
+  override fun onBind(intent: Intent?): IBinder? = null
+
+  private fun createNotificationChannel() {
+    val channel =
+      NotificationChannel(CHANNEL_ID, "Eval Service Channel", NotificationManager.IMPORTANCE_LOW)
+    val manager = getSystemService(NotificationManager::class.java)
+    manager?.createNotificationChannel(channel)
+  }
+
+  private fun createNotification(port: Int): Notification {
+    return NotificationCompat.Builder(this, CHANNEL_ID)
+      .setContentTitle("Gallery Eval Server")
+      .setContentText("Running on port $port")
+      .setSmallIcon(android.R.drawable.ic_media_play)
+      .build()
+  }
+
+  companion object {
+    private const val TAG = "EvalService"
+    private const val CHANNEL_ID = "EvalServiceChannel"
+    private const val NOTIFICATION_ID = 1
+
+    const val ACTION_START_SERVER = "com.google.ai.edge.gallery.eval.START_SERVER"
+    const val ACTION_STOP_SERVER = "com.google.ai.edge.gallery.eval.STOP_SERVER"
+  }
+}