startop: Add a validator to check the correctness of event sequence.

Change-Id: Ic764cfe4f3f98e14e756897d6dcdc8c167d8a728

2 files changed, 257 insertions, 0 deletions

diff --git a/startop/iorap/src/com/google/android/startop/iorap/EventSequenceValidator.java b/startop/iorap/src/com/google/android/startop/iorap/EventSequenceValidator.java
new file mode 100644
index 000000000000..b75510b576f6
--- /dev/null
+++ b/startop/iorap/src/com/google/android/startop/iorap/EventSequenceValidator.java
@@ -0,0 +1,255 @@
+/*
+ * Copyright (C) 2019 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.android.startop.iorap;
+
+import android.annotation.NonNull;
+import android.annotation.Nullable;
+import android.content.Intent;
+import android.util.Log;
+
+import com.android.server.wm.ActivityMetricsLaunchObserver;
+
+/**
+ * A validator to check the correctness of event sequence during app startup.
+ *
+ * <p> A valid state transition of event sequence is shown as the following:
+ *
+ * <pre>
+ *
+ *                                +--------------------+
+ *                                |                    |
+ *                                |        INIT        |
+ *                                |                    |
+ *                                +--------------------+
+ *                                          |
+ *                                          |
+ *                                          ↓
+ *                                +--------------------+
+ *                                |                    |
+ *            +-------------------|   INTENT_STARTED   | ←--------------------------------+
+ *            |                   |                    |                                  |
+ *            |                   +--------------------+                                  |
+ *            |                             |                                             |
+ *            |                             |                                             |
+ *            ↓                             ↓                                             |
+ * +--------------------+         +--------------------+                                  |
+ * |                    |         |                    |                                  |
+ * |   INTENT_FAILED    |         | ACTIVITY_LAUNCHED  |------------------+               |
+ * |                    |         |                    |                  |               |
+ * +--------------------+         +--------------------+                  |               |
+ *            |                              |                            |               |
+ *            |                              ↓                            ↓               |
+ *            |                   +--------------------+       +--------------------+     |
+ *            |                   |                    |       |                    |     |
+ *            +------------------ |  ACTIVITY_FINISHED |       | ACTIVITY_CANCELLED |     |
+ *            |                   |                    |       |                    |     |
+ *            |                   +--------------------+       +--------------------+     |
+ *            |                              |                            |               |
+ *            |                              |                            |               |
+ *            |                              ↓                            |               |
+ *            |                   +--------------------+                  |               |
+ *            |                   |                    |                  |               |
+ *            |                   | REPORT_FULLY_DRAWN |                  |               |
+ *            |                   |                    |                  |               |
+ *            |                   +--------------------+                  |               |
+ *            |                              |                            |               |
+ *            |                              |                            |               |
+ *            |                              ↓                            |               |
+ *            |                   +--------------------+                  |               |
+ *            |                   |                    |                  |               |
+ *            +-----------------→ |        END         |←-----------------+               |
+ *                                |                    |                                  |
+ *                                +--------------------+                                  |
+ *                                           |                                            |
+ *                                           |                                            |
+ *                                           |                                            |
+ *                                           +---------------------------------------------
+ *
+ * <p> END is not a real state in implementation. All states that points to END directly
+ * could transition to INTENT_STARTED.
+ *
+ * <p> If any bad transition happened, the state becomse UNKNOWN. The UNKNOWN state
+ * could be * accumulated, because during the UNKNOWN state more IntentStarted may
+ * be triggered. To recover from UNKNOWN to INIT, all the accumualted IntentStarted
+ * should termniate.
+ *
+ * <p> During UNKNOWN state, each IntentStarted increases the accumulation, and any of
+ * IntentFailed, ActivityLaunchCancelled and ActivityFinished decreases the accumulation.
+ * ReportFullyDrawn doesn't impact the accumulation.
+ */
+public class EventSequenceValidator implements ActivityMetricsLaunchObserver {
+  static final String TAG = "EventSequenceValidator";
+
+  private State state = State.INIT;
+  private long accIntentStartedEvents = 0;
+
+  @Override
+  public void onIntentStarted(@NonNull Intent intent, long timestampNs) {
+    if (state == State.UNKNOWN) {
+      Log.e(TAG, "IntentStarted during UNKNOWN." + intent);
+      incAccIntentStartedEvents();
+      return;
+    }
+
+    if (state != State.INIT &&
+        state != State.INTENT_FAILED &&
+        state != State.ACTIVITY_CANCELLED &&
+        state != State.ACTIVITY_FINISHED &&
+        state != State.REPORT_FULLY_DRAWN) {
+      Log.e(TAG,
+          String.format("Cannot transition from %s to %s", state, State.INTENT_STARTED));
+      incAccIntentStartedEvents();
+      incAccIntentStartedEvents();
+      return;
+    }
+
+    Log.i(TAG, String.format("Tansition from %s to %s", state, State.INTENT_STARTED));
+    state = State.INTENT_STARTED;
+  }
+
+  @Override
+  public void onIntentFailed() {
+    if (state == State.UNKNOWN) {
+      Log.e(TAG, "IntentFailed during UNKNOWN.");
+      decAccIntentStartedEvents();
+      return;
+    }
+    if (state != State.INTENT_STARTED) {
+      Log.e(TAG,
+          String.format("Cannot transition from %s to %s", state, State.INTENT_FAILED));
+      incAccIntentStartedEvents();
+      return;
+    }
+
+    Log.i(TAG, String.format("Tansition from %s to %s", state, State.INTENT_FAILED));
+    state = State.INTENT_FAILED;
+  }
+
+  @Override
+  public void onActivityLaunched(@NonNull @ActivityRecordProto byte[] activity,
+      @Temperature int temperature) {
+    if (state == State.UNKNOWN) {
+      Log.e(TAG, "onActivityLaunched during UNKNOWN.");
+      return;
+    }
+    if (state != State.INTENT_STARTED) {
+      Log.e(TAG,
+          String.format("Cannot transition from %s to %s", state, State.ACTIVITY_LAUNCHED));
+      incAccIntentStartedEvents();
+      return;
+    }
+
+    Log.i(TAG, String.format("Transition from %s to %s", state, State.ACTIVITY_LAUNCHED));
+    state = State.ACTIVITY_LAUNCHED;
+  }
+
+  @Override
+  public void onActivityLaunchCancelled(@Nullable @ActivityRecordProto byte[] activity) {
+    if (state == State.UNKNOWN) {
+      Log.e(TAG, "onActivityLaunchCancelled during UNKNOWN.");
+      decAccIntentStartedEvents();
+      return;
+    }
+    if (state != State.ACTIVITY_LAUNCHED) {
+      Log.e(TAG,
+          String.format("Cannot transition from %s to %s", state, State.ACTIVITY_CANCELLED));
+      incAccIntentStartedEvents();
+      return;
+    }
+
+    Log.i(TAG, String.format("Transition from %s to %s", state, State.ACTIVITY_CANCELLED));
+    state = State.ACTIVITY_CANCELLED;
+  }
+
+  @Override
+  public void onActivityLaunchFinished(@NonNull @ActivityRecordProto byte[] activity,
+      long timestampNs) {
+    if (state == State.UNKNOWN) {
+      Log.e(TAG, "onActivityLaunchFinished during UNKNOWN.");
+      decAccIntentStartedEvents();
+      return;
+    }
+
+    if (state != State.ACTIVITY_LAUNCHED) {
+      Log.e(TAG,
+          String.format("Cannot transition from %s to %s", state, State.ACTIVITY_FINISHED));
+      incAccIntentStartedEvents();
+      return;
+    }
+
+    Log.i(TAG, String.format("Transition from %s to %s", state, State.ACTIVITY_FINISHED));
+    state = State.ACTIVITY_FINISHED;
+  }
+
+  @Override
+  public void onReportFullyDrawn(@NonNull @ActivityRecordProto byte[] activity,
+      long timestampNs) {
+    if (state == State.UNKNOWN) {
+      Log.e(TAG, "onReportFullyDrawn during UNKNOWN.");
+      return;
+    }
+    if (state == State.INIT) {
+      return;
+    }
+
+    if (state != State.ACTIVITY_FINISHED) {
+      Log.e(TAG,
+          String.format("Cannot transition from %s to %s", state, State.REPORT_FULLY_DRAWN));
+      return;
+    }
+
+    Log.i(TAG, String.format("Transition from %s to %s", state, State.REPORT_FULLY_DRAWN));
+    state = State.REPORT_FULLY_DRAWN;
+  }
+
+  enum State {
+    INIT,
+    INTENT_STARTED,
+    INTENT_FAILED,
+    ACTIVITY_LAUNCHED,
+    ACTIVITY_CANCELLED,
+    ACTIVITY_FINISHED,
+    REPORT_FULLY_DRAWN,
+    UNKNOWN,
+  }
+
+  private void incAccIntentStartedEvents() {
+    if (accIntentStartedEvents < 0) {
+      throw new AssertionError(
+          String.format("The number of unknows cannot be negative"));
+    }
+    if (accIntentStartedEvents == 0) {
+      state = State.UNKNOWN;
+    }
+    ++accIntentStartedEvents;
+    Log.i(TAG,
+        String.format("inc AccIntentStartedEvents to %d", accIntentStartedEvents));
+  }
+
+  private void decAccIntentStartedEvents() {
+    if (accIntentStartedEvents <= 0) {
+      throw new AssertionError(
+          String.format("The number of unknows cannot be negative"));
+    }
+    if(accIntentStartedEvents == 1) {
+      state = State.INIT;
+    }
+    --accIntentStartedEvents;
+    Log.i(TAG,
+        String.format("dec AccIntentStartedEvents to %d", accIntentStartedEvents));
+  }
+}
diff --git a/startop/iorap/src/com/google/android/startop/iorap/IorapForwardingService.java b/startop/iorap/src/com/google/android/startop/iorap/IorapForwardingService.java
index f753548516ef..badff7bc2f8c 100644
--- a/startop/iorap/src/com/google/android/startop/iorap/IorapForwardingService.java
+++ b/startop/iorap/src/com/google/android/startop/iorap/IorapForwardingService.java
@@ -283,6 +283,7 @@ public class IorapForwardingService extends SystemService {
     }
 
     private final AppLaunchObserver mAppLaunchObserver = new AppLaunchObserver();
+    private final EventSequenceValidator mEventSequenceValidator = new EventSequenceValidator();
     private boolean mRegisteredListeners = false;
 
     private void registerInProcessListenersLocked() {
@@ -303,6 +304,7 @@ public class IorapForwardingService extends SystemService {
         ActivityMetricsLaunchObserverRegistry launchObserverRegistry =
                 provideLaunchObserverRegistry();
         launchObserverRegistry.registerLaunchObserver(mAppLaunchObserver);
+        launchObserverRegistry.registerLaunchObserver(mEventSequenceValidator);
 
         mRegisteredListeners = true;
     }